Virulence Factors Of Cryptoccus Neoformans

Virulence Factors Of Cryptoccus Neoformans
Cryptococcus neoformans (Cn) is a basidiomycete fungus that causes cryptococcosis worldwide in immunodeficiency and healthy individuals. In this
pathogen, the elaboration of virulence factors including melanin and the capsule depends on intact intracellular trafficking, an essential cellular process
also required for nutrient uptake, ion homeostasis, and receptor recycling. Our previous studies have found that Cn evolves a cryptococcal intersectin
(Cin1)–regulated endocytic pathway essential for growth and virulence. We have also obtained evidence linking Cin1 to extracellularRNA through
RNA–Seq and to CNS survival through co–infection of a mouse model of cryptococcosis. However, how Cin1 governs the transport network affecting
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Specifically, we will find if Cin1 orchestrates the only endocytic pathway and how it affects host–parasite interaction through regulating exRNA
transport and mouse CNS survival. We propose three specific aims: Aim 1 is to determine if Cin1 mediates the sole endocytic pathway in Cn through
identification and characterization of pathway components. Aim 2 is to examine the role of Cin1 in exRNA export through continued annotation and
analysis of RNA–Seq data. Aim 3 is to further explore the CNS survival advantage of Cin1–S by generating the Cin1–L strain using one–step
CRISPR–Cas9 mutagenesis method we recently developed and testing it through co–infection.
Our central hypothesis is that intracellular trafficking is important in pathogen growth and interaction with a host resulting pathogenesis (our long–term
goal). We propose those specific aims to test the hypothesis that Cn evolves a distinct Cin1 endocytic pathway necessary for pathogenesis (short term
goal). Through studying a fundamental cellular process and its adaptation to pathogenesis of Cn, our investigation could lead to the discovery of novel
antifungal targets. 2. Specific Aims
Cryptococcus neoformans (Cn) virulence depends on active transport of vesicles that contain melanin and capsule precursors, proteinases, and other
macromolecules. We found that Cin1 is critical in mediating intracellular trafficking affecting growth and virulence and that Cin1–S isoform exhibits a
marked survival advantage in the
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C Difficile
Clostridium difficile is a gram–positive spore–forming bacteria; first isolated and published in 1935 by Hall and O'Toole. This was accomplished from
the stool of a healthy infant. However, it was not until 1978 that C. difficile was identified as being associated with many cases of antibiotic–resistant
diarrhea.1 C. difficile has since become one of the leading causes of nosocomial infections in the United States. A study conducted in 2015 has
estimated that C. difficile infection has an incident of 453,000 (95% confidence interval) in the United States.2 This has placed a tremendous burden
on the US healthcare system. According to data from 2008, C. difficile infections have accumulated an excess cost of $4.8 billion to the US healthcare
system.3... Show more content on Helpwriting.net ...
difficile has had on the US population, many biochemical and physiological studies on C. difficile have been conducted. In order to grow C. difficile, a
defined culture medium containing the minimum essential nutrients is required. These nutrients include several essential vitamins and amino acids.
The essential vitamins include biotin, pantothenate and pyridoxine. The essential amino acids include cysteine, isoleucine, leucine, proline, tryptophan
and valine. In addition, arginine, glycine, histidine, methionine and threonine have been shown to enhance the growth of C. difficile.4 As a pathogen,
C. difficile utilizes two main toxins. The virulence factors, toxin A (TcdA) and toxin B (TcdB), are from the large clostridial toxins family and target
the Rho and Ras family GTPase within the host cells.5 Diversity in the genome of C. difficile have been identified and shown to produce strains with
increased virulence.6 It should be noted, however, that strains without virulence factors, non–toxigenic C. difficile (NTCD), do exist and have been
shown to colonize in humans. NCTD is a topic of interest in their potential to reduce the risk of infection by virulent strains of C.

Using Quorum Sensing Mechanism And The Inhibition Of Qs
Abstract:
Several antibiotic resistant bacterial strains exist due to the inappropriate usage of antibiotics themselves as a result of this an alternative treatment is
required. Quorum sensing (QS) is a process of cell–cell communication, which controls the expression of virulence factors by pathogenic bacteria.
There is evidence to suggest that the inhibition of QS in bacteria would reduce or inhibit virulence factors being produced and could also prevent
biofilm formation. This review focuses on quorum sensing mechanism and the inhibition of QS in gram–negative bacteria. QS inhibition has been
explored as a novel anti–pathogenic therapy to control bacterial infections with promising results in several previous studies.
Introduction
Excessive and indiscriminate usage of antibiotics has led to the emergence of multiple drug resistant (MDR) bacterial strains. The need for alternative
approaches to combat these MDR strains stem from the fact that 16 million people die annually due to infectious diseases caused by them (Bjarnsholt.
et al., 2005 and Rasmussen. et al., 2005). It has been repeatedly observed that bacteria within these specialised structures are around 1000 times more
resistant to antibiotics than their free–living counterparts (Martinez and Baquero, 2002). Bacterial behaviour within biofilms is regulated by a process
named quorum sensing (QS), where bacteria release chemical signals and express virulence genes in a cell density dependent manner (Ganin et al.

Non Pathogens
Pathogen research
After the introduction of the pathogen, it was clear that various non–pathogens could cause harm to people. The concept of the pathogen was initially
was referred to microbe causing the disease. Scientists have involved themselves in research to critical understand the properties of fungi, bacteria,
parasites and viruses that were able to make people become ill. During the research, there were seminal discoveries that were able to be got
(Casadevall and Pirofski). These included various roles of fungal and bacterial toxins available in diseases. Microbe, however, causes diseases only
with the host. In 1950, the microbes that caused infections were common opening channel of skin and blood relating to the treatments suppressing ...
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Researchers studying microorganisms' community use genomics recognize myriad factors and interactions help shape the composition of the
microorganism. However, in different people, the microbe varies in development at various times with relation to the disease. Infectious research on
the diseases is dominated continuously by reducing the approaches (Casadevall and Pirofski). The microbiologists view the microbes of any disease as
the major factors that vary with the disease. They, therefore, treat the body of the host as just a

Essay Yersinia pestis
Yersinia pestis– Bacteria Virulence and Symptoms
Yersinia pestis appeared fairly early in history and is still prevailing today. Humans have come in contact with this bacterium in massive outbreaks
throughout history, including the most famous Black Death of the 14th century. From the lack of knowledge of thebacteria and its ability to infect
populations rapidly, the human race has suffered immensely. The bacterium is specialized with specific plasmids, Yersinia outer proteins as well as
other toxins that it uses to disrupt the body's immune response. Through this, Yersinia pestis avoids harm and effectively infects the circulatory system
of its host causing three forms of the plague: Bubonic, Pneumonic and Septicemic. Each form of ... Show more content on Helpwriting.net ...
This rapidly deadly disease, characterized by these certain factors, enable the bacterium to eventually lead the host into a painful death. 2
The bacteria, Yersinia pestis, is encoded with two specific plasmids that aid in the transfer and survival of the bacteria, especially in the wild. Both
of these plasmids must be present on the bacteria for full virulence of the organism. The largest of the extrachromosomal elements, with typical
strains of ~100 kb, is the Murine toxin plasmid (pFra), a capsule protein. pFra is characterized by two specific factors: FI capsular protein antigen and
YMT. The second plasmid, Pesticin plasmid named pPla after the plasminogen activator, happens to be the smallest of the plasmids. The bacteriocin
(pesticin;Pst) and the bilanolysin and coagulase activities are found to be connected with one another and aids the former organism of Yersinia in the
invasion of "the host from peripheral sites" (Carniel 41). After the bacteria is injected through a bite of the rat flea, Yersinia pestis affects theimmune
system similar to the bacterial agent, Bacillis anthracis. By having a Type III secretion system, the bacteria are able to find "a means ? to target
virulence factors directly at host cells". The common Yersinia encoded plasmid molecule, pYV (or pLcr), found on the bacteria specifically aids in the
injection of cytotoxic proteins into the macrophages, preventing the

Dr. Indrani Bose's Seminar, вЂњUsing RNA Interference to...
On Friday, January 31, 2014 Dr. Indrani Bose gave a seminar about her area of research, and discussed her research objectives. The title of the seminar
was "Using RNA Interference to Understand the Virulence and Biology of the Yeast Cryptococcus neoformans". At the beginning, she first compared
and contrasted the budding yeasts of Saccharomyces cerevisiae and Cryptococcus neoformans. According to Dr. Bose in the mini–review, AYeast
under Cover: the Capsule of Cryptococcus Neoformans, "C. neoformans is a fungus that is ubiquitous in the environment, where it is found in soil, in
association with certain trees, and in bird guano (16)" (1). She also stated because of its ubiquity, that most people had probably been exposed to it
from a young ... Show more content on Helpwriting.net ...
Bose stated that her long term goal is to discover better drugs to eradicate this disease from developing in humans. She intends to do this by identifying
the genes that are involved in the disease process, and assessing their function. From that point she will attempt to discover or design drugs to inhibit
these genes from functioning. There are several factors that affect the virulence of Cryptococcus neoformans; from its polysaccharide capsule, to its
ability to grow at high temperatures, and its formation of melanin. The last two factors are absolutely necessary to the pathogenicity of the fungi (1).
The Dr. Bose discussed RNA Interference. She said that RNA Interference is used as a tool for "forward genetics", and that it selectively destroys
specific mRNAs, which in turn creates "knock down" phenotypes. Forward genetics is the random inactivation of 1–2 genes at a time, allowing for
selectivity of the phenotype. At this point, she began to describe the results from running RNA interference on the Cryptococcus neoformans genome.
She discovered that there was too much expression of ADE–2, so she developed a stable marker, URA–5. The URA–5 selected for robust RNA
Interference. She discovered that the cells that did well with URA–5 would survive treatment with 5–fluororotic acid, and the cells that did poorly with
URA–5 would not survive the treatment. She also determined that silencing was RDP1 dependent. RDP1 is a wild type gene.
Then she developed a library

Calf Diarrhoea
Calf diarrhoea is one of the most economic and pervasive concern in veterinary industry all over the world (Nguyen et al., 2011). It isn't a single disease
entity but is a complex syndrome with complex etiopathogenesis causing important economic losses directly through mortality and indirectly through
treatment costs and reduced growth rates in affected calves (Radostits et al.,
2007). In addition to economic losses, diarrhoea in livestock is important because of public health implications as numerous infectious agents causing
diarrhoea in animals are zoonotic and have been associated with food– borne diseases
(Trevejo et al., 2005). During the course of diarrhea, hematological and biochemical parameters are disturbed and these changes are ... Show more
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AAPs have been proposed as valuable indicators for the manifestation and severity of pathological conditions in humans and animals (Otto et al.,
2000).To date, diarrhoegenic
E.coli have been divided into 6 pathotypes based on virulence properities; Enterohaemorrhagic
(EHEC) or Shigatoxin–producing (STEC),
Enteropathogenic (EPEC), Enterotoxigenic
(ETEC), Enteroinvasive (EIEC), Enteroaggregative
(EAEE) and diffusely adherent E. coli (DAEE).
EHEC strains are a subset of shiga toxin producing E. coli (STEC). Infection with non–
O157 STEC strains have been associated with diarrhoea and dysentery in young calves (Sandhu and Gyles, 2002) and severe outbreaks of
gastrointestinal illness in humans ranging from diarrhea and Hemorrhagic Colitis (HC) to the lifethreatening
Hemolytic Uremic Syndrome (HUS)
(Lynn et al., 2005). Sporadic cases and large outbreaks in humans are associated with contact with STEC positive animals or environment (Caprioli et
al., 2005). The pathogenicity of human and bovine STEC strains is mediated by number of virulence factors including shiga toxins (encoded by Stx1
and

Bioprospection Analysis Essay
In silico bioprospection analysis is the process and application for the development of a novel natural product that can be achieved from utilizing
digital information scattered all across web network in a systematic and scientifically validated manner. The present chapter provides the outcome of
the analysis of web based classical data search, matrix linked data mining followed by fuzzy logic based optimization and validation using molecular
docking analysis. Such analysis identified potent nutraceuticals with a physiological functional indicator of combined effects of progression of
multi–drug resistant (MDR) Salmonella typhimurium (S. typhimurium) infections in pre–existing inflammatory disorder (RA). These indicators are
useful for... Show more content on Helpwriting.net ...
1) Fuzzy set membership analysis for decision matrix & optimization: The following mathematical relationship as mentioned below (Eqs. 2) was used
to ascertain relative relevance within an identified set of herbals. ОјS=((S–Min S))/((Max S–Min S))(Eqs. 2) Molecular Docking: To validate the
bioprospection model, docking simulations of predominant phytoconstituents against most relevant bioactivity parameter was carried out using
Maestro 9.4, Schrodinger, USA Estimation of Physiological Function Indicator (HО”I) Nutraceuticals were evaluated for their Physiological function
indicators (HО”I) utilizing the following formula: HО”I=E value (test)Г·Evalue (control) The average was also calculated by using HО”I value taken
together for estimating the most efficient herbal compound. 4.2 Results 4.2.1 Classical Bioprospection Classical Bioprospection exhibited 100 herbals
combining individual analysis of RA and S. typhimurium. The common plants based on clinical manifestation showed37 nutraceuticals common to
both categories. This primary database is part of reviewing of literature thus, enlisted as probable nutraceuticals targeting pre–existing inflammatory
disorder suffering from opportunistic infections (Table 2.4). The list of a plants rationale based selection of rheumatic and virulence factors
targetingpathophysiologiyRA aggravated by the impact of MDR S. typhimuriumasshown in Table 4.1 and

Taking a Look at Lipoproteins
Lipoproteins are multicomponent assemblies of lipids and proteins that form distinct molecules with an approximate stoichiometric value between the
lipid and protein components within the complex. Lipoproteins exist with many types each with a specific molecular mass, size, density, physiological
role, and chemical composition.(devlin,57) The lipids and their derivatives may be covalently or non–covalently bound to the proteins. Lipoproteins
show biodiversity in their forms, many enzymes, antigens, toxins, structural proteins, transporters, emulsification agents in lipid uptake, and adhesins
are lipoproteins with an important network that supports the transportation of fats in blood stream and inside and outside of cell, as building blocks using
cholesterol to offer a great help in maintaining the water content of the cell by building membranes, and keeping the internal structure organized.
Examples include High density lipoproteins and low density lipoproteins which help in fats relocation, and their associated diseases like
Atherosclerosis. Another group of diseases is associated with bacterial lipoproteins physiological virulence of many medically relevant pathogens. (http:
//www.news–medical.net/health/What–are–Lipoproteins) ( Lipoproteins of Bacterial Pathogen, A. Kovacs–Simon, R. W. Titball and S. L. Michell)
Bacterial Lipoproteins :
Bacterial lipoproteins are a group of membranous proteins with broad functionality which exhibit lipid–protein based roles in the

Mucormycosis And Pathogenesis Essay
Mucormycosis is an emergent and lethal infection caused by Mucoralean species. Using Mucor circinelloides as a model of mucormycosis to identify
new genetic determinants of virulence is the aim of this work. First strategy parts from identification of genes differentially expressed during
pathogenesis, choosing zebra fish as an infection model (Fig. 1).
Figure 1. Transcriptomic analysis during infection with M. circinelloides virulent and avirulent strains revealed several genes either induced (green) or
repressed (red) during zebrafish infection, in both avirulent and virulent strains.
The most induced gene during infection encodes a multicopper ferroxidase, which shares high homology with Fet3 protein sequence from other fungi.
This gene, named fet3a, could be involved in the reductive iron uptake mechanism during infection as a virulence determinant. ... Show more content on
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(A) Expression of fet3 genes in M. circinelloides in low iron conditions. Iron–depleted media were obtained by adding Fetal Bovine Serum or
1,10–Phenanthroline to control media. (B) Densitometric analysis of hybridization signals showed in (A).
Bioinformatic analysis revealed the presence of two fet3a homologs, fet3b and fet3c, in M. circinelloides genome. Northern blot hybridization validated
fet3a RNA–seq results, and showed an upregulation of the three fet3 genes triggered by low iron availability (Fig. 3). These results imply that fet3
genes are functionally redundant, suggesting that fet3b and fet3c are complementing fet3a deletion during infection on the host Galleria

Group B Streptococcus Agalactiae
Group B Streptococcus agalactiae is an important Gram–positive bacterial pathogen that cause a wide variety of clinical infections, ranging from
septicemia to meningitis. The reported lethality of severe S. agalactiae infections is ranging from 4 to 6% in the United States. Of note, it has been
suggested that the incidence of neonatal disease is considerably greater than reported, because the requirement for positive cultures from blood or
cerebrospinal fluid may underestimates the true burden of disease. Therefore, in this review I focused on virulence factors of S. agalactiae in order to
elucidate aspects of the infection.
S. agalactiae is frequently colonizes rectovaginal tract. S. agalactiae is found in 15–40% of adult women, and there is a 1% chance to be transmitted
vertically from mother to infants before or during birth. This type of infection is divided into early–onset and late–onset infections. Early–onset
infection, is one of the most common infection among neonates with a mortality rates of 4 to 6% in the United States. This type of infection is
characterized with shock and breathing difficulties and occurs at birth or within the first 6 days of life. This infant probably had become infected by
ascending spread of the organism from the maternal genital tract to the amniotic fluid, in which the bacteria colonize and multiply within the respiratory
tract of the fetus and causes pneumonia. Also, this bacteria may enter the respiratory tract and spread to the

Essay on Streptococcus Pneumoniae
In accordance with the World Health Organization, pneumonia still remains one of the main killers of children under the age of five, taking more than
1.1 million lives of boys and girls annually (WHO Pneumonia factsheet, 2013). Pneumonia is more prevalent in South Asia and sub–Saharan Africa. It
is well known that pneumonia is a disease of respiratory system that affects the alveoli, which are the constituent part of the lungs. Normally alveoli fill
with air during the breath of a healthy person, while the one with pneumonia has alveoli, which are filled with fluid and pus; hence the breathing
process is painful and limits the oxygen consumption by organism. Pneumonia can be caused by several infectious agents, such as bacteria, fungi and ...
S. pneumoniae is capnophilic, preferring atmospheres of 5–10% carbon dioxide. Streptococcus pneumoniae can be distinguished from other
streptococci, owing to the fact that it is catalase negative; can be inhibited by ethyl hydrocupreine; it is soluble in bile (due to activation of autolytic
property, which consequently lead to cell lysis); it is О±–haemolytic (it can be easily identified on agar plates, due to greenish discoloration of blood
agar due to the production of pneumolysin) (Balakrishnan, 2006).
S. pneumoniae has some distinct virulence factors, which are proteins/enzymes that are expressed on the surface of gram–positive organisms. They are
also the main contributors to the pathogenic character of the bacterium and its survival against the host defense mechanisms. According to Poll et al.
(2009) virulence factors should be used in array, in order to be successful in coordinating ways for the tissue invasion. Some of the most important
virulence properties are the adherence factors, genes responsible for invasion, some heavy–metal transporters, evasion the immune system of the host,
production of pneumolysin and bacteriocin, quorum sensing and formation of bioп¬Ѓlms. Some centuries ago, S. pneumoniae's polysaccharide capsule
was considered to be the primary virulence factor, due to the fact that the capsule is crucial for colonization, invasion and dissemination from the
respiratory tract. This capsule is negatively charged and hence inhibits the

Honey Bee Virulence Report
Discussion With this information, it can help build the foundations needed to find anti–virulence factors against P. larvae to reduce the need for
antibiotics. The current treatments options available for AFB are becoming progressively obsolete due to antibiotic resistance. Honey bee colonies are
constantly exposed to these antibiotics until approximately two weeks before the honey is collected (Caron and Connor, 2013). As mentioned
previously, this is the only effective way of killing the vegetative cells, but not the spores. The spores still persist within the colony and once the
bacterium becomes resistant to treatment, it results in disastrous outcomes (Caron and Connor, 2013). Therefore, treatments that could neutralize these
virulence factors should be sought after. Also, with the use of antibiotics, there are possibilities of toxic residues being found in the honey. This could
take a devastating toll on the individuals who consume this hive product. Therefore, the need for natural treatments are becoming popular because of
regulations related... Show more content on Helpwriting.net ...
It provides the necessary knowledge of whether or not honey bee larvae can survive and develop in a laboratory setting. Once possible treatment options
begin to emerge, the uninfected larvae could be exposed to these alternatives. These larvae can be observed for any anomalies throughout the
developmental period to determine the effects of these potential treatments. Unfortunately, during the experimental process none of the larvae made it
to the adult stage in the control plate. This was partly due to the development of mold during the larval stage. With the elevated humidity levels and the
presence of condensation within the incubator, it provided optimal conditions for mold growth. The mold caused undesirable larval death for almost
half of the larvae; therefore, it may have skewed the

Cross Sectional Study Of STEC Shedding In Cow Herds
Venegas–Vargas et al. (2016) conducted a cross–sectional study of STEC shedding in dairy and beef cattle herds in Michigan. STEC was found to be
more prevalent in beef cattle (21%) versus dairy cattle (13%). Factors significantly associated with STEC shedding in dairy cattle included when
maximum average temperatures exceeded 28.9C 1–5 days prior to sampling; animals in their first lactation; and animals less than 30 days in lactation.
The authors suggested that possible control strategies could be considered for animals in their first lactation and/or within the first 30 days of
lactation. Daily cleaning of cattle feeders reduced risk of STEC shedding compared with feeders cleaned less frequently. There is a poor understanding
of the... Show more content on Helpwriting.net ...
coli classes was highly skewed toward NLNS (non–LEE non–STEC E. coli; negative for all 4 tested E. coli virulence factors), in 85–95% of milk
samples. The authors did not find a correlation between seasonal effects and presence of virulence factors. Lambertini (Lambertini, Karns et al. 2015)
noted the challenges associated with direct cultural identification of pathogenic E. coli due to the wide diversity of E. coli subtypes in manure and
feces. Aside from O157:H7, isolating STEC strains is confounded by lack of metabolic differences that can be utilized for their discrimination. The
isolation of O157:H7 from manure and fecal samples requires labor intensive extraction with immunomagnetic beads and use of expensive
chromogenic agars. By using qPCR to detect four virulence factor genes associated with enteropathogenic E. coli, the authors were able to conduct
direct semi–quantitative comparison of the relative abundance of virulence factors within the E. coli community associated with the analyzed sample.
The authors cautioned that this cannot predict with certainty the presence of a specific pathogenic serotype but implies its possible presence. Virulence
factor patterns consistent with E. coli O157:H7 were not detected in any milk samples, and only 0–2% of milk filter samples, confirming that even
when STEC and EHEC are present in cow feces, appropriate sanitary practices effectively lower the risk of milk contamination. This study indicated
that well water

Major Characteristics Of Pseudomonas Aeruginosa
I. Description of P. aeruginosa
Pseudomonas aeruginosa is characterized by aerobic, gram negative, motile, non–spore forming bacilli (rods).1 A trait that differentiates P. aeruginosa
from other gram–negative bacteria is the fact that it produces indophenol oxidase, which is an enzyme that renders them positive in an oxidase test.1
The type of flagella this organism is known to possess is called a polar flagella, meaning a single flagellum at one pole of the rod.1 This means the
motility of the organism is quite limited and can travel only in one direction. In spite of this, the single flagellum, as well as the presence of pili, are
major contributions to the motility of Pseudomonas aeruginosa.1 The Pseudomonas genus, the genus from which P. aeruginosa originates from, is
known to be an environmental bacteria; hence why this organism is very common in soil, water, and even fresh fruits and vegetables.1 A common
characteristic of environmental bacteria, P. aeruginosa being of no exception, is the ways in which they grow. P. aeruginosa grows and thrives in
biofilms which are groups of adhering bacteria in aqueous environments. These biofilms eventually begin to produce a slimy substance resembling glue
which allows them to spread and stick to other materials/locations. Not only does P. aeruginosa require minimal nutritional requirements, but the entire
Pseudomonas genus type does as well.1 Due to P. aeruginosa (usually) only needing acetate as carbon and ammonia as nitrogen,

Infections of the American Chestnut Tree Essay
Cryphonectria parasitica, a filamentous, ascomycete fungus, is the causal agent of the chestnut blight5,14 which was introduced to North America
from Japan circa 190412,14.The chestnut blight infects all members of the Castanea family14, and some members of the genus Quercus though C.
parasitica infections are superficial14. A C. parasitica infection typically begins at a branch node or wound in the tree's bark 14. Once a spore has
entered the tree, hyphal growth begins14. When the fungi's hyphae reach the cambium, the xylem and phloem are blocked, cutting off the transport of
water and nutrients and a sunken canker is formed14. Eventually, the lack of water and nutrients kills the tree above the point of infection14. As a
fungus, C. ... Show more content on Helpwriting.net ...
One excellent use for blight–resistant American chestnuts is reclaiming surface mines. Though other species of trees can survive in the harsh
conditions typical of surface mines, they have little to no value as lumber and provide little for wildlife4. Chestnuts would also provide a fast growing
lumber source, one that is lightweight, strong, and moderately rot–resistant. Additionally, the large nut crops produced by the Americanchestnut would
increase the ecosystems carrying capacity for wildlife, and moderate population fluctuations that follow mast (nut crop) fluctuations. For these and
other reasons which space here does not permit, restoring the American chestnut is worthwhile endeavor.
Although C. dentata is not resistant to an infection by the blight fungus, it is not entirely defenseless. One attempt at warding off C. parasitica is the
growth of callus encircling the fungi's mycelium to prevent its spread (cite). This may or may not work, in either case the fungi will spread to another
site on the tree via sporulation. A second barrier to blight infection is the chestnut's relatively high levels of tannic acid(s) in the cambium (cite).
However, as will be discussed later, tannic acids may benefit the blight. The most promising method for increasing C. denata's blight resistance is The
American Chestnut Foundation's breeding program. To give the chestnut the advantage in its battle with its evolutionary foe, it is necessary to study
the factors that make C.

The E Coli Is A Gram Negative, Rod Shaped Bacterium
The E–coli is a gram–negative, rod–shaped bacterium. It can grow under aerobic (extra–intestinal) or anaerobic conditions (intestine) and is the
predominant facultive organism in human's GI tract. It belongs to the bacterial family of Enterobacteriaceae. It is an important member of the
intestinal human's micro–flora. It usually adheres to the mucus overlying the large intestine. Nowadays, pathogenic E–coli are classified based on their
unique virulence factors. Pathogenic strains of the bacterium cause three different diseases: (8)
Urinary tract infections
Neonatal meningitis
Intestinal diseases
Each of the diseases depends on different expression of virulence factors such as adhesins, invasins, chemotaxis, toxins and the ability of the E–coli to
defend its host. (8)
Uropathogenic E–coli colonize from perineal region and ascend to the bladder. The virulence factor expressed is P fimbria. The strains also express
other virulence factors such as siderophores that play a role in obtainment of iron for the bacteria. They also express haemolysins. A–haemolysin lyse
the lymphocytes and ОІ–haemolysin inhibits the phagocytosis of neutrophils. Another virulence factor is the resistance to the complement–dependent
bactericidal effect. The presence of K antigens promotes bacterial virulence by decreasing the ability of antibodies or complement to bind to the
bacterial cell surface and cause the loss of phagocyte's ability to recognize and destroy them. (8)
Neonatal meningitis

Aeruginosa Case Studies
aeruginosa is a Gram–negative bacterium capable of surviving in a wide range of environments. It is an opportunistic pathogen and it is commonly
associated with nosocomial infections and infections of severely burned individuals, and are a leading cause of death in severe respiratory infections1.
In particular, P. aeruginosa is the leading cause of chronic pulmonary infections and mortality in cystic fibrosis (CF) patients2. Infections with P.
aeruginosa are difficult to eradicate, due to their high levels of antibiotic resistance and growth in biofilms3.
Bacterial communication occurs through a well– developed system termed the quorum sensing (QS) system. QS system is the regulation of gene
expression in response to fluctuations in cell–population density. Quorum sensing bacteria produce and release chemical signal molecules called
autoinducers that increase in concentration as a function of cell density. Cell–cell communication via autoinducers occurs both within and between ...
aeruginosa12. Analysis of patients sputa revealed the presence of both lasI and lasR transcripts13. Other studies upon different animal models of P.
aeruginosa infections including the thermally injured mouse model and the mouse models of acute and chronic lung infections revealed the
importance of QS in the virulence of P. aeruginosa 14,15,16,17. These studies compared the virulence of P. aeruginosa mutants that carried deletions
within QS genes with that of their parent strain. They showed that the mortality rate among thermally injured mice infected with QS mutants was
significantly lower than that in mice infected with the parent strain. In addition, the mutants were significantly defective in their ability to spread either
locally within the thermally injured skin or systemically within the bodies of the thermally injured/infected

Group A Streptococcus (GAS) Essay
Streptococcus pyogenes, also known as Group A streptococcus (GAS), is a ОІ–hemolytic, Gram–positive bacterium that most commonly causes
respiratory disease, including pharyngitis or tonsillitis, as well as skin infections such as impetigo and cellulitis. The organism is transmitted via
respiratory droplets or by contact with fomites, and commonly infects young children. In addition to the common clinical presentations associated with
S. pyogenes, some individuals develop the postinfectious sequelae of rheumatic fever and glomerulonephritis. Due to the severity of these medical
consequences, prophylactic antibiotic use is often recommended for any patients with otherwise mild S. pyogenes infections (21).
In addition to its traditional ... Show more content on Helpwriting.net ...
Antibiotic use, particularly with clindamycin and linezolid, may be useful in treating GAS–associated necrotizing fasciitis, as they target both
M–proteins and exotoxins (5). Some cases have been treated with hyperbaric oxygen therapy, with recent data suggesting prompt surgical therapy
instead is vital for preventing amputations (18). Even after treatment, however, necrotizing fasciitis mortality has been estimated to range from
24%–60% (10).
In S. pyogenes–associated necrotizing fasciitis, the bacteria first invade host fascia before spreading and causing more invasive damage. Initial GAS
invasion can occur through three primary pathways: 1) preceding superficial infection; 2) direct inoculation; or 3) hematogenous seeding from a
previous injury site. After colonization, GAS spread through the typically sterile fascial planes that separate muscle groups, which are only loosely held
together by connective tissue. The streptococci then release several proteases and other virulence factors that cause localized tissue damage.
Simultaneously, this dissemination prompts the arrival of acute inflammatory host cells; the response of polymorphouclear leukocytes (PMNs), in
particular, can also contribute to the tissue damage characteristic of necrotizing fasciitis. Once the

Global Climate Change Is The Future Of The Entire Generation
Global climate change transcends the future of the entire generation. Yunjing Wang mentions that the world is expecting warming that could be
dangerous throughout the century (Wang et al., 2015). Not only effecting species of animals but also determining the presence of human existence.
New diseases prevail on a daily basis specifically vector borne. These vector borne illnesses adapt to climate change due to temperature fluctuations,
constant precipitation, and population adjustments. Although diseases such as Malaria and Zika are being researched on a daily basis, preventative
measures for diseases caused by climate change are being acted upon by many organizations. If a steady climate can arise in the near future, virulence
of many climate–related diseases will eventually decline. The dynamics of climate influence virulence due to unstable temperatures. The effects on the
quality of life creates vulnerability to those that surround these 'virulent' environments. It is referenced that extreme outbreaks occur after major
disturbances to the population (McMichael, 2015). These climatic events tend to trigger microbes, pathogens, and hosts to start infecting the nearest
populous whether it be animal or human. As McMichael mentions, microbes have the capacity that is stronger willed than any biotechnological
application and can reproduce a stable metabolism and maintain a relationship in the most severe disturbance (2015). McMichael, also states that
human–driven climate

Essay Salmonella and Enteritis or Systemic Diseases
Salmonella
Introduction
Salmonella is known as a gram–negative, rod shaped bacillus. It is a facultative anaerobe in the family Enterobacteriaceae (Todar). There are more
than 1,000 known types of Salmonella, with ranging levels of toxicity (Jones), accounting for 60% of all bacterial diseases (Curtello). Salmonellosis
has affected over 1.4 million people per year in the United States, including more than 500 fatal cases (Jones). This organism has a wide host range
with abilities to attack both animals and humans (Tartakow). Salmonella's main habitat is in the intestinal tracts of warm blooded animals (Jones). It
best grows at a temperature between 5 and 47 degrees Celsius (Pui). Non–host adapted Salmonella may reside in food or water ... Show more content on
Helpwriting.net ...
Since it has such a long incubation period, this suggests that Salmonella typhimurium is able to avoid detection by the host immune system early in the
course of infection (Helene). The non–host adapted Salmonella cause very diverse typhoid–like symptoms and is most common cause for foodborne
infections (Todar). Gastroenteritis is characterized by a sudden onset of fever, abdominal pain, vomiting, diarrhea, and dehydration. Diarrhea is a result
of secretions of fluids by the small and large intestines. These symptoms are caused by acute inflammatory responses given off by the bacteria within
the intestine (Giannella). In extreme cases S. typhimurium could affect respiratory, central nervous or cardiovascular systems causing things like
pneumonia and meningitis. The severity of symptoms depends on the type, amount ingested, a person's age, and susceptibility to illnesses. Elderly
people and young children are the most vulnerable to symptoms of Salmonellosis. Symptoms can begin to appear anywhere between six and
forty–eight hours and can last three days or even three weeks.
Septicemia is another form of the manifestation of Salmonella in the body. This is known as the intermediate stage of the infection and does not cause
intestinal symptoms. Also, the bacteria are unable to be eradicated from the fecal matter secreted by an infected host. The harshness of the specific
infection is dependent on the endurance of the patient

The Role Of Spna As A Cell Wall
Figure 1: Kaplan–Meier survival curves of wax worms infected with labelled dose (CFUs) of GAS SpnA variants over 3 days **** P<0.05 (One–way
ANOVA) A methyl green assay allows quantification of DNAse activity by measuring the change in absorbance as the methyl green
–DNA complex is
degraded (Sinicropi et al. 1994). The SpnA knockout had significantly lower DNAse function than wildtype GAS whilst the non–functional
complements showed similar activity to the knockouts and the functional complements showed an intermediate function in between that of the
knockout and that of the wildtype (Fig. 5) All strains showed higher activity than buffer alone (Fig. 5). Discussion Previous experiments have
characterised the role of SpnA as a cell wall anchored DNAse important for immune evasion through the destruction of neutrophil extracellular traps
(NETs) (Buchanan et al. 2006). While small scale in vivo experiments in mice have been conducted (Hasegawa et al. 2010), a Galleria mellonella
infection model allows for a larger scale screening of mutants to further refine the role of SpnA in GAS virulence. This is due to the lower cost, easy
maintenance, small size and suitability of the wax worm (Ramarao et al. 2012). In the above experiments, the role of SpnA in GAS virulence was
clearly demonstrated by the significant difference in killing and the health index of the caterpillars between wild type and О”SpnA. They also revealed
that complementation with cell wall bound SpnA on a plasmid

Write An Essay On Ebola Virus
Name:TaLissa Battieste_
Causative Agent: Ebola Hemorrhagic Fever
Disease: Ebola Virus
Classification of the causative agent:
The Ebola virus is a member if the family filoviridae and the order mononegavirales and is the causative agent of the Ebola Hemorrhagic Fever. These
are enveloped viruses that have mini–genomes consisting of a single RNA molecule of negative or anti–MRNA sense. There are five different Ebola
virus genomes (BDBV, EBOV, RESTV, SUDV and TAFV) that differ in sequence and the number and location of gene overlaps.
History:
Most cases of the Ebola virus are located on the African continent. It was first identified in a province of Sudan and in a nearby region of Zaiire in
1976 after significant epidemics in Yambuku and Nzara, both in Africa.... Show more content on Helpwriting.net ...
Different strains of Ebola may have slight changes in their structure, indicating that virulence is mutagenic. The virus contains a nucleocapsid which
gives it some virulence as well.
Mode of transmission:
Ebola is transmitted in humans through the direct contact of blood or bodily fluids of a person infected with the virus. Examples of these fluids include
diarrhea, sweat, vomit, semen, urine, and breast milk. The virus can enter through breaks in the skin or mucous membranes including the nose, mouth
and eyes. Ebola is not an airborne disease that is transmitted through sneezing and coughing however large droplets from a person who is sick could be
infectious.
Incubation Period of the Disease:
The time interval from infection with the virus to the onset of symptoms, better known as the incubation period is 2–21 days. The average period is
8–10 days. Humans are not infections until they develop symptoms. Ebola is an acute viral infection with a rapid onset, brief period of symptoms and
resolution within days.

Signs and

Gastrointestinal Tract Research Paper
Abstract After entering the gastrointestinal tract on the way to their physiological site of infection, enteric bacteria encounter a remarkable diversity in
environmental conditions. There are gross differences in the physico–chemical parameters in different sections of the Gastrointestinal tract (GI) tract
e.g. between the stomach, small intestine and large intestine. Furthermore, even within a certain anatomical site, there are subtle differences in the
microenvironment e.g. between the lumen, mucous layer and epithelial surface. Enteric pathogens must not only survive passage through the rapidly
changing environments encountered at different niches of the GI tract but must also appropriately coordinate expression of virulence determinants...
Several studies have revealed pathogen specific responses to bile that alter the expression of virulence factors. When V. cholerae was grown in
the presence of bile, expression of the essential virulence genes ctxAB and tcpA was drastically repressed [30]. Since bile is a heterogeneous
mixture, crude bile was fractionated, and the components that mediate virulence gene repression were identified. It was shown that unsaturated
fatty acids (UFAs) present in bile, arachidonic, linoleic, and oleic acids were responsible for repression of ctxAB and tcpA genes [31]. However,
expression of toxT encoding the direct transcriptional activator of ctxAB and tcpA was not affected and ToxT protein levels were similar between
V. cholerae grown in the presence or absence of bile or UFAs [31]. Subsequently, the crystal structure of ToxT revealed that unsaturated fatty acids
can bind to ToxT and keeps ToxT in a 'closed' conformation that is not capable of binding DNA [32]. Hence ToxT cannot activate expression of
ctxAB and tcpA in the presence of bile or UFAs and the genes continue to be repressed by H–NS [33]. Bile also causes drastic repression of virulence
genes in salmonellae. Salmonellae grown in the presence of bile demonstrated a marked

The Common Urinary Tract Infection
Bacterial urinary tract infections represent the most common type of nosocomial infections. Often, the ability of bacteria to both establish and maintain
these infections are directly related to biofilm formation on indwelling devices or within the urinary tract itself (30). Enterococci (especially E. faecalis)
are one of the main causative agents of urinary tract infection and Catheter–associated urinary tract infections (CAUTIs) besides gram–negative
pathogens (31, 32). In these infections Biofilm provides a favorable milieu for microbial survival within the host as the organisms are shielded from the
host immune response, as well as antibiotics and antimicrobial agents (33, 34). Several studies conducted to introduce main virulence genes of
enterococci that are associated with biofilm formation in these bacteria (11, 13,–17), but virulence mechanism and related genes for biofilm formation
are not well understood (35). In this study we investigated biofilm formation of clinical enterococci isolates isolated from Urinary tract infections.
These strains were characterized for presence of adhesions and secretory virulence factors. Isolates had diverse presence of virulence from lack to
highest amount of virulence genes. Several previous studies investigated relation of virulence genes and biofilm formation, especially presence of esp
and gel. Enterococci esp has been implicated as a contributing factor in colonization and persistence of infection within the urinary tract

Disease Essay Examples
Thought Paper: Pathogens Are Rare & Virulence Varies Greatly Less than 1% of bacteria can invade our bodies and making us ill [5]. Such bacteria
are pathogenic and have the potential to be disease causing. This means that the remaining 99% are rather ubiquitous in nature and serve beneficial
purposes or have no effect on humans. Pathogens vary in complexity and those that remain are a direct result of successfully adapting to their
environments and evolving over time to overcome selective evolutionary pressures. A more specific example of how disease causing pathogens can
vary in virulence involves the mention of antibiotics and their ability throughout history to temporary lessening the virulence of bacterial strains. The
relationship... Show more content on Helpwriting.net ...
Therefore, virulence varies among isolated cultures, although the origins of these evolutionary adaptations on a molecular level are all interconnected
and can be studied though tracing genetic elements of between bacterial populations and those found in animals and humans [3]. Studies in the past
tried to directly tie the two phenomena together and confirmed that increased usage of antibiotics were directly correlated with increased resistance to
those specific antibiotics. A finding was additionally mentioned that diversifying the antibiotics used to eliminate bacterial populations and reduction
in overall use of antibiotics would minimize the levels of resistance in certain bacterial species most commonly found in hospitals [8]. Additionally,
Studies found that certain bacterial species with increased exposure to antibiotics are highly prevalent in waste water of hospitals. High levels of
resistance displayed in these populations pose as a major risk to environmental health if released beyond clinical waste water systems. Untreated
wastewater is therefore an immediate cause of concern [8]. Thus, with this data from past and current studies, pathogens are not in themselves rare, but
virulence does vary due to increased exposure to antibiotics and gained resistance that has spread and will continue to do so unless habits are changed
with a

The Prevalence Of E. Coli
4– Results
4.1The prevalence of E. coli isolates according to a source of water The results showed that there was a high frequency of E. coli isolates in tap water
40/46 (86.9%) and low frequency of isolates in Tank 1/46 (2.2%) as showed in figure 4–1. Figure 4–1: The prevalence of E. coli isolates according to a
source of water.
4.2 The prevalence of E. coli isolates according to the place
The results showed that there was a high frequency of isolates from houses 36/46 (78.3%) followed by dormitory (15.2%) and (2.2%) from pharmacy,
company and cafeteria in figure 4–2.
Figure 4–2: The prevalence of E. coli isolates according to the place.
4.3. The prevalence of E. coli isolates according to the ward and the province ... Show more content on Helpwriting.net ...
coli virulence factor isolate according to ward and province. The diarrheagenic E. coli virulence factors are distributed according to the ward and
province as shown in table 4–3, there is a high frequency of IPaH gene 9 (19.6%) in ward as same as in province 9 (19.6%).
Table 4–3: The presence of virulence factors of E. coli isolates according to the ward.
SourceAggRStxIPaHeaetotal ++++
Khartoum6
(13.0%)3
(6.5%)9
(19.6%)0
(0.00%)
18
(39.1%)
Omdurman5
(10.9%)0
(0.00%)7
(15.2%)0

(0.00%)
12
(26.0%)
Bahri3
(6.5%)2
(4.3%)3
(6.5%)0
(0.00%)
8
(17.3%)
Total14
(30.4%)5
(10.9%)19
(41.3%)0
(0.00%)
38
(82.6%)
Key: + positive
4.6 Antimicrobial susceptibility of diarrheagenic E. coli isolated from drinking water samples Table 4–4 showed antimicrobial susceptibility patterns of
diarrheagenic E. coli isolated from drinking water. 67.4% of them were sensitive to Chloramphenicol, (63%) to Ceftriaxone, (52.2%) to Ciprofloxacin
and (41.3%) to Gentamicin with high resistance rate to Tetracycline 97.8%. Table 4–4: The activity of antibiotics on E. coli isolated from drinking water.
AntibioticsSensitiveResistanceIntermediateTotal
Chloramphenicol31
(67.4%)8
(17.4%)7
(15.2%)46
(100%)
Ceftriaxone29
(63.0%)4
(8.7%)13
(28.3%)46
(100%)
Ciprofloxacin24
(52.2%)11
(23.9%)11

(23.9%)46

Bacterial Quorum Sensing ( Qs )
Introduction: Bacterial Quorum Sensing (QS) Although traditionally thought to be a multicellular characteristic, unicellular bacteria populations
behave cooperatively by means of small, diffusible chemical signals. The inter and intraspecies bacterial pheromone communication creates behavior
synchronization within a species. The timing of a host infestation, genetic modification for niche adaptation based on a new energy source, or the
production of a secondary defense metabolite are all examples of cooperative behavior that depend on intercellular bacterial communication (Everts,
2006). The bacterial cell–to–cell communication process is referred to as quorum sensing (QS). Pheromones that act as cell–to–cell communicators are
also called autoinducers (AIs), as they function to stimulate their own synthesis (Williams, Winzer, Chan, & Camara, 2007). AIs are produced and are
continually released by bacteria at relatively low levels. The production, detection, and response of bacterial populations are determined by the
concentration of the AIs. As binary fission occurs and the bacterial population density increases, there is an increase in the relative concentration of AIs
in the nearby environment. As receptors bind to the AI, a quorum sensing circuit is initiated, and bacteria collectively alter gene expression for
processes that benefit from collaborative action, such as: bioluminescence, sporulation, competence, biofilm adherence and formation, antibiotic

Is Rhodococcus Equi Virulence Plasmids?
Rhodococcus equi Virulence Plasmids
Mobile genetic elements have the ability to encode bacterial pathogenicity, metabolic functions, and resistance factors. Genes that encode other toxins
known as phage encoded, and plasmid encoded Gram negative, and Gram positive organisms have the ability to spread among a population. Gene
transfer by plasmid and phage encoded microorganisms may play a role in the creation of new pathogenic variants. Other virulence factors can be
found on the chromosome, and can function as virulence blocks. Specific areas on these genes are known as pathogenicity islands.These islands show
us that genetic elements that effect bacterial virulence and the genetic flexibility of certain bacterium. They may be involved in the process of
microbial evolution. ... Show more content on Helpwriting.net ...
Research on this bacteria had already been conducted, and this was related to the previous experiments.R. equi is a species of a pathogenic bacteria
that is source of pulmonary infections in humans and animals. Its niche specialization is plasmid decided. A plasmid is a genetic element that is
expendable and replicate separately from chromosomes. Plasmids usually carry a variety of nonessential genes, that are usually very helpful. In the
case of R. equi, its plasmid encoded functions promote animal host colonization and carry a pathogenicity island called vap PAI. A Pathogenicity
island (PAI) can be more specifically defined as large chromosomal region that carries many virulence genes; usually present in pathogenic strains and
contains mobility

Differences Between Viruses And Widespread Spread
There is a trade–off between rate of transmission and duration of infection. If a pathogen can gain increased reproduction by using host resources, or
doing anything that helps itself and hurts the host, that tactic can be selected for. A pathogen gains from leaving the host mobile, which generally
entails leaving the host alive. A virus spreads only if an infected individual passes the virus on to more than one new host.
However, if a virus is too aggressive and kills its host fast its fitness is not as successful. When the virus makes its host sicker, it reduces its ability to
spread due to death or isolation from other people. The virus would then have a low evolutionary fitness unless it sufficiently increases its chance of
being transmitted by killing its host.
When a virus infects a new host species they may be susceptible to highly virulent strains. In order to be successful in ... Show more content on
Helpwriting.net ...
Droplet occurs when bacteria or viruses travel on relatively large respiratory droplets that people sneeze, cough, drip, or exhale, such as the common
cold. Airborne transmission is similar. Viruses travel on dust particles that become aerosolized when people sneeze, cough, laugh, or exhale, and hang
in the air. They can travel on air currents over large distances. Anthrax, Chickenpox, Influenza, Measles, Smallpox, and Tuberculosis are examples of
this .
Vector–borne disease organisms are important factors that promote the evolutionary increases of virulence. Disease organisms transmitted through
vectors like mosquitoes, tend to be much more damaging than diseases that are simply transmitted by people coughing or sneezing (droplet
transmission). In vector– borne diseases immobilizing the host does not prevent transmission, but it might even enhance it. Experimental studies
indicate that mosquitoes are better able to bite a laboratory animal when it is sick with a vector–borne disease such as malaria than when it is healthy

Study of Genes Found in Streptococcus Agalctiae
Streptococcus agalactiae is a known pathogen and is widely known as an important cause of invasive disease in neonates. In this report the
pathogenicity of this organism was investigates by looking at the distribution of genes found in Streptococcus agalctiae which appear to play an
important role in the virulence of this pathogen. The distribution of these virulence genes was investigated in Streptococcus agalactiae samples
recovered from neonates who had experienced an invasive disease and samples recovered from the vaginas of women who naturally have this
organism as a commensal.
The bacterial capsule which includes serotype specific antibodies has a critical role to play in the virulence of this organism (Smith et al, 2006). The
other virulence factors include;
The BCA gene which encodes for the alpha C protein, which is a virulence factor on the surface of Streptococcus agalactiae. (Foxman et al, 2007).
The RIB gene which expresses a surface protein called RIB which is found in Streptococcus agalactiae strains isolated from infections caused by the
pathogen (Cabezon et al, 1996). . This protein confers protective immunity, which classifies this protein as a virulence gene. It is expressed by most
strains causing life threatening infection, including almost all strains of serotype III (Cabezon et al, 1996). The Rib protein is found to share several
properties with the alpha proteins. Both alpha and rib proteins are resistant to trypsin and vary greatly in size

Escherichia Coli : An Important Food Borne Zoonotic Pathogen
Escherichia coli, is the most prevalent pathogen which is commonly known for its affiliation with human and animal infections and diseases such as
diarrhoea, in addition to several clinical symptoms including haemorrhagic colitis, haemolytic uremic syndrome (HUS), and thrombocytopenic purpura
(Liu et al., 2012; Vanaja et al., 2010; Tomat et al., 2013). HUS in humans, is caused by a predominant type of enterohaemorrhagic E. coli (EHEC) in
the United States. It is also the chief cause of acute renal failure in children. There has also been documentation of strings of outbreaks since its
identification as a pathogen in 1982, happening basically in Canada, Japan, United Kingdom and United States, implicating domestic animals such as
sheep,... Show more content on Helpwriting.net ...
This has been a more pragmatic approach to the control of these pathogens because of the development of antibiotic resistance. This therapy has been
used profitably since the early 1920s and encouraging results have been generated by the use of phage–mediated biocontrol of pathogenic E. coli in
animals such as pigs and cows. A study was done on calves and piglets who had diarrhoea due to experimentally administered pathogenic E. coli.
Results showed they were cured within 8 hours after phage administration. More studies also revealed that phage could act very successfully as a
prophylactic. Recent results of phage therapy against other bacterial pathogens have also shown great potential. For example, it has been shown that
intraperitoneal injections of bacteria (Staphylococcus aureus) finally cause death in mice while the application of intraperitoneal injection of phage
after that of the bacteria very much reduces the fatality of the bacteria (O'Flynn et al., 2004; Biswas et al., 2002; Clark and March, 2006).
Regardless of the pathogenic E. coli, some species are non–pathogenic strains which are normal and ecological essential inhabitants of the human and
animal gastrointestinal tracts. Non–pathogenic and pathogenic E. coli differ with respect to the presence of genetic information that may

Evolution Of The Immune System And Parasite Virulence
The Evolution of the Immune System and Parasite Virulence as a Response to Immunopathology
Ryan Thompson
Introduction
Virulence can be defined as the damage that is cast upon a host by a parasite (Alizon et al., 2009; Sorci 2013). As virulence increases, a parasite
becomes more deadly, as it causes more harm to its host (Shudo and Iwasa 2003). The Trade–Off theory, the idea that a more virulent parasite tends to
be transmitted early on in infection, is often believed to be the main driving force behind the evolution of virulence in parasites (Alizon et al., 2009,
Cooper et al., 2002). The problem with the Trade–Off theory is that it does not accommodate for the impact of the immune system on virulency as a
result of immunopathology ... Show more content on Helpwriting.net ...
Type 1 cytokines mainly target smaller parasites, like viruses, while Type 2 cytokines target larger parasites, typically worms (Graham, et al.,
2005). Some of the first studies of Type 1 cytopathic immune responses were with Tumor Necrosis Factor (Tracey and Cerami, 1994). Tumor
Necrosis Factor (TNF), a cytokine produced in response to invasion by a parasite, was found to cause tissue damage to the host during its response
to a viral invasion, causing a reaction very similar to septic shock (Tracey and Cerami, 1994). For larger infections, Type 2 cytokines are the most
common immune response (Graham et al., 2005). While attempting to repair tissue damage caused by worms, these cytokines can often overcorrect
the problem, causing fibrosis (Graham et al., 2005). In addition to these cytokine responses, the immune system also implements reactive T cells to
help fight off parasites (Aandahl et al., 2004). These T cells can be immunopathic, but they also possess the ability to regulate both cytokine responses
and other T cell responses (Aandahl et al., 2004). These regulatory T cells may have evolved as part of the immune system's response to
immunopathology. Over time evolution favored T cells that regulate the cytokine response, which helps avoid septic shock, increasing the fitness of the
host's immune system.
Evolution of the Immune System in Response to Immunopathology Immunopathology has led many scientists to believe that the

E. Coli : Factors For Source Of Water And Place
4.4 detection of diarrheagenic E. coli virulence factors isolate according to source of water and place. The diarrheagenic E. coli virulence factors
distribution according to the source of water and place is showed in table 4–1 and 4–2, the high frequency of virulence factors is IPaH 15 (32.6%) in
tap water, a high frequency of IPaH 19 (30.4%) in houses.
Table 4–1: The presence of virulence factors from E. coli isolates according to source of water.
Source AggRStxIPaHeaeTotal ++++
Tap water 11
(23.9%)5
(10.8%)15
(23.6%)0
(0.0%)31
(67.3%)
Cooler 3
(6.5%)0
(0.0%)4
(8.7%)0
(0.0%)7
(15.2%)
Tank 0
(0.0%)0
(0.0%)0
(0.0%)0
(0.0%)0
(0.0%)
Total 14
(30.4%)5
(10.09%)19

(41.3%)46
(100.0%)38
(82.6%)
Key: + positive ... Show more content on Helpwriting.net ...
Table 4–4: The activity of antibiotics on E. coli isolated from drinking water.
AntibioticsSensitiveResistanceIntermediateTotal
Chloramphenicol31
(67.4%)8
(17.4%)7
(15.2%)46
(100%)
Ceftriaxone29
(63.0%)4
(8.7%)13
(28.3%)46
(100%)
Ciprofloxacin24
(52.2%)11
(23.9%)11
(23.9%)46
(100%)
Gentamicin19
(41.3%)11
(23.9%)16
(34.8%)46
(100%)
Tetracycline1
(2.2%)45
(97.8%)0
(0.0%)46
(100%)
4.7 The correlation between the antimicrobial susceptibility and presence of virulence factors. There was significant correlation (p–value> 0.05(;
between the presence of the Stx gene and sensitivity to Ciprofloxacin, between the presences of IPaH gene and sensitivity to Ceftriaxone and between
the presences of Stx gene and the sensitive to Tetracycline (p–value> 0.05( as shown in table 4–5.

Table 4–5: The correlation between the antimicrobial susceptibility and the presence of virulence factors of E. coli.
Spearman 's rhoAggRStxIPaHeae
Ciprofloxacin0.1050.317*–0.1400.105 0.4860.0320.3520.486
Chloramphenicol0.0320.238–0.253. 0.8320.1110.090.
Ceftriaxone0.1150.2620.377**. 0.4470.0780.010.
Gentamicin0.2170.219–0.171. 0.1480.1430.257.
Tetracycline0.2250.427**–0.125. 0.1320.0030.408. *Correlation is significant at P. value в‰¤ 0.05 **Correlation is significant at P. value в‰¤ 0.01
4–7

Enterococci
Enterococci are gram positive cocci that can occur singly, in pairs or as short chains. They are facultative anaerobes, possessing the ability to grow in
the presence or absence of oxygen. Enterococci can withstand harsh environmental conditions. There are currently 23 enterococci species and they are
divided into five groups based on their interaction with mannitol, sorbose and arginine 5 .E. faecalis can survive extreme challenges. Its pathogenicity
ranges from life–threatening diseases in compromised individuals such as bacteremia, septicemia, endocarditis, and urinary tract infections to less
severe conditions, such as infection of obturated root canals with chronic apical periodontitis.The persistence of E.faecalis might be due to the

Necrosis Research Paper
The Flesh Fating Disease Necrosis is abnormal death of cells that are likely caused by disease or infection. Necrotizing fasciitis "the flesh eating
disease" is caused by several bacteria (mixed flora, aerobic and anaerobic), the most common and deadly is Streptococcus pyogenes (S. pyogenes) or
group A streptococcus. Characteristics are Gram positive, nonmotile, nonsporeforming, beta hemolytic catalase negative, cocci that are spherical
bacterium that appears in chain–like formations. S. pyogenes are considered a facultative anaerobic bacterium; it can grow in the presence or absence
of oxygen. Growth is stimulated by incubating in an environment with increased carbon dioxide. Type I caused by anaerobic bacteria with or without
the presence ... Show more content on Helpwriting.net ...
It begins with a harmless cut in the skin and spreads rapidly into nearby tissue. When streptococci on the skin are introduced to the cut, strains of
group A release enzymes and toxins that greatly increase invasiveness and virulence. Invasive bacteria are pathogens that can invade parts of the body
where bacteria are not normally present, such as the bloodstream, and soft tissues like muscle or fat. Virulence is the degree of pathogenicity
determined by its ability to establish itself in a host and survive the host defense. Virulence factors of group A streptococci include (1) M protein and
lipoteichoic acid for attachment; (2) a hyaluronic acid capsule that inhibits phagocytosis; (3) other extracellular products, such as pyrogenic
(erythrogenic) toxin, which causes the rash of scarlet fever; and (4) streptokinase, streptodornase (DNase B), and streptolysins. Some strains are
nephritogenic. Immune–mediated sequelae do not reflect dissemination of bacteria. Nongroup A strains have no defined virulence factors. Antibody to
M protein gives type–specific immunity to group A streptococci. Antibody to erythrogenic toxin prevents the rash of scarlet fever. Immune mechanisms
are important in the pathogenesis of acute rheumatic fever. S. pyogenes produce several virulence factors that lend to its pathogenicity, or
disease–causing capabilities. It contains a capsule that helps allow the bacteria to disguise it from getting engulfed by white blood cells
(phagocytosis). It also contains proteins on its cell wall that allows it to adhere to epithelial cells, which allows it to produce disease. S. pyogenes also
produces several enzymes that give the bacteria the ability to destroy tissue and spread. The enzymes digest the connective tissue in the skin. Lastly, it
produces a wide variety of toxins that can produce

S. Aureus Epidemic: A Case Study
Staphylococci are spherical gram–positive cocci arranged primarily in form of irregular clusters. They are present mostly in the upper respiratory tract
and on the other epithelial surfaces of warm–blooded animals. The genus Staphylococci are mainly contains 20 species amongst S. aureus is
considered as a common pyogenic agent in humans and several animal species, and constitutes a primary cause of mastitis in dairy cattle (Virgin et al.,,
2009).
S. aureus is one of the most important amongst Staphylococci species. The species is found primarily on human skin, mucous membranes and can also
be found in other areas of human contact including soil, water, and food products. The species is capable of causing a wide variety of diseases,
including septicaemia, sepsis, wound sepsis, septic arthritis, osteomyelitis, food poisoning, ... Show more content on Helpwriting.net ...
It lives on the skins of humans and animals and can easily be transferred to food products (Mousa.,, et al 2014) Staphylococcal food poisoning
represents a considerable social burden in terms of hospital expenses, loss of patient's working days and productivity, together with the problems and
the cost of disposing the contaminated food.
The severity of the infection was varied according to many elements in particular the pathogenicity and virulence of the causative strain. The virulence
of S. aureus is generally a multifactorial and due to the combined action of several virulence determinants, which augment tissue colonization, tissue
damage, and hence disease (Bien et al.,, 2011), these proteins facilitate the bacterial attachment and colonization within the cellular and extracellular
material of the host. Moreover, cellular proteins, protease, and toxins, which inhibit phagocytosis and thus interfere with the ability of the host to
actively, hinder infection by a specific immune response. Hemolysin and other enzymes aid the bacterial population in the invasion of the host tissues
(Lowy, 2000). S. aureus can bind a variety of proteins

Rocky Mountain Spotted Fever Disease
Question and Evidence
What is the specific microbiology for the Rocky Mountain spotted fever disease? The foreground information presented in the single study research
article, "Targeted Knockout of the Rickettsia rickettsii OmpA Surface Antigen Does Not Diminish Virulence in a Mammalian Model System" will
facilitate answering that question.
Findings/Answers to Question Those diagnosed with Rocky Mountain spotted fever, the most severe type of spotted fever, have the rickettsia rickettsii
bacterium to thank. This gram–negative obligate intracellular pathogen has varying levels of virulence, from avirulent to highly virulent, and thus the
severity of the disease differs among individuals. Highly virulent strains include the Sheila Smith strain and an avirulent strain is the Iowa strain.
Despite their virulence, various strains of the rickettsia rickettsii pathogen have the potential to be transmitted to humans by arthropod vectors, like
ticks. The article also notes that ... Show more content on Helpwriting.net ...
rOmpA and rOmpA proteins are found across various strains of rickettsia rickettsiibacteria and play a role in pathogenesis through adhesion and
invasion. It is noted that due to a premature stop codon, rOmpA is not produced in the avirulent strains of the rickettsia rickettsii bacteria and thus, it is
thought that OmpA may play a role in virulence. This hypothesis was tested by inserting an isogenic ompA mutant– to create a premature stop codon
– into a guinea pig infected with the highly virulent Shelia Smith strain. It was evident that this did not affect the duration or severity of illness versus
the control guinea pig. From these findings it was concluded, and as the title of the article states, "the rickettsia rickettsii OmpA surface antigen does
not diminish virulence in a mammalian model

Statement Of Purpose In Molecular Biology
For all my life, due to rapid increase in the number of cancer patients and my fear of it, I was thinking about a new way to find a drug that can treat
it without major side effects. That's why I planned to study pharmacy to be aware of cancer biology and latest approaches for it's treatment. Then I
decided to continue my studies and to get my masters in the field of Molecular Biology so I can perform researches and try to find a new treatment for
this disease. since my financial abilities is not well established, I was searching how to win a scholarship and what are the requirements to get, and I
found that scholarships are very competitive. So, I worked to be qualified to be accepted into one of the reputable university scholars so I can ... Show
more content on Helpwriting.net ...
I'm doing research to inhibit bacterial virulence factor production to decrease its resistance resulted from mess use of antibiotics, making it easy for the
immune system to overcome bacterial infection by using Drug re purposing techniques. The results are promising and I'm preparing to publish it soon.
Additionally, I was working in my field of interest –Molecular Biology– trying to explore a new method for treating cancer. I found a mechanism using
gene therapy techniques by applying chemical modifications on the nucleotide which hopefully can be used in treatment, which was on my professors'
point of view is theoretically acceptable. I also presented it in Mansora university at one of the annual scientific conferences and I got the 8th position.
But, unfortunately we have not the ability to work on it practically because gene therapy techniques are expensive and we have not such facilities and
techniques. That's why I intended to continue my studies abroad in a country with better research abilities . This opportunity will definitely help me in
my career pathway to have deeper studies in

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