Stele is defined as a central vascular cylinder, with or without pith and delimited the cortex by endodermis.
Van Tieghem and Douliot (1886) recognized only three types of steles.
1-Protostele
2-Siphonostele
3-Solenostele
Stelar Theory:
Major highlights of stellar theory are:
Stele is a real entity and present universally in all higher plants.
Cortex and stele are two fundamental parts of a shoot system
Stele and cortex are separated by endodermis.
The slides has been edited. visit for new one on https://www.slideshare.net/alihaider408/stelar-system-stele-its-types-and-evolutionedited-182037813
Sorry for inconvenience.
Stele is defined as a central vascular cylinder, with or without pith and delimited the cortex by endodermis.
Van Tieghem and Douliot (1886) recognized only three types of steles.
1-Protostele
2-Siphonostele
3-Solenostele
Stelar Theory:
Major highlights of stellar theory are:
Stele is a real entity and present universally in all higher plants.
Cortex and stele are two fundamental parts of a shoot system
Stele and cortex are separated by endodermis
The slides has been edited. visit for new one on https://www.slideshare.net/alihaider408/stelar-system-stele-its-types-and-evolutionedited-182037813
Sorry for inconvenience.
Stele is defined as a central vascular cylinder, with or without pith and delimited the cortex by endodermis.
Van Tieghem and Douliot (1886) recognized only three types of steles.
1-Protostele
2-Siphonostele
3-Solenostele
Stelar Theory:
Major highlights of stellar theory are:
Stele is a real entity and present universally in all higher plants.
Cortex and stele are two fundamental parts of a shoot system
Stele and cortex are separated by endodermis
This is a detailed presentation on Morphology, anatomy and reproduction of Marchantia spp. with high quality pics and eye capturing transitions and animations
Gnetum: A Powerpoint Presentation on Gymnospemsshivduraigaran
The Gymnosperms are a group of seed-producing plants (spermatophytes) that includes conifers (Pinophyta), cycads, Ginkgo, and gnetophytes. The term "gymnosperm" comes from the Greek composite word γυμνόσπερμος (γυμνός gymnos, "naked" and σπέρμα sperma, "seed"), meaning "naked seeds". The name is based on the unenclosed condition of their seeds (called ovules in their unfertilized state). The non-encased condition of their seeds stands in contrast to the seeds and ovules of flowering plants (angiosperms), which are enclosed within an ovary. Gymnosperm seeds develop either on the surface of scales or leaves, which are often modified to form cones, or solitary as in Yew, Torreya, Ginkgo.
The gymnosperms and angiosperms together compose the spermatophytes or seed plants. The gymnosperms are divided into six phyla. Organisms that belong to the Cycadophyta, Ginkgophyta, Gnetophyta, and Pinophyta (also known as Coniferophyta) phyla are still in existence while those in the Pteridospermales and Cordaitales phyla are now extinct.
By far the largest group of living gymnosperms are the conifers (pines, cypresses, and relatives), followed by cycads, gnetophytes (Gnetum, Ephedra and Welwitschia), and Ginkgo biloba (a single living species). Roots in some genera have fungal association with roots in the form of micorrhiza(Pinus), while in some others(Cycas) small specialised roots called coralloid roots are associated with nitrogen fixing cyanobacteria.
Gnetum is a genus of gymnosperms, the sole genus in the family Gnetaceae and order Gnetales. They are tropical evergreen trees, shrubs and lianas. Unlike other gymnosperms, they possess vessel elements in the xylem. Some species have been proposed to have been the first plants to be insect-pollinated as their fossils occur in association with extinct pollinating scorpion flies. Molecular phylogenies based on nuclear and plastid sequences from most of the species indicate hybridization among some of the Southeast Asian species. Fossil-calibrated molecular-clocks suggest that the Gnetum lineages now found in Africa, South America and Southeast Asia are the result of ancient long-distance dispersal across seawater
The "Telome theory" of Walter Zimmermann (1930, 1952) is the most accepted theory that is based on fossil record and synthesizes the major steps in the evolution of vascular plants.
It describes how the primitive type of vascular plants developed from Rhynia like plants.
This ppt has been made by Xanthophyceae also known as yellow green algae. It occupies second position in algae classification by F.E Fritsch. It is classified into four orders. It contain xanthophyll in large amount that gives it yellow colour, hence it is commonly know as yellow green algae.
This is a detailed presentation on Morphology, anatomy and reproduction of Marchantia spp. with high quality pics and eye capturing transitions and animations
Gnetum: A Powerpoint Presentation on Gymnospemsshivduraigaran
The Gymnosperms are a group of seed-producing plants (spermatophytes) that includes conifers (Pinophyta), cycads, Ginkgo, and gnetophytes. The term "gymnosperm" comes from the Greek composite word γυμνόσπερμος (γυμνός gymnos, "naked" and σπέρμα sperma, "seed"), meaning "naked seeds". The name is based on the unenclosed condition of their seeds (called ovules in their unfertilized state). The non-encased condition of their seeds stands in contrast to the seeds and ovules of flowering plants (angiosperms), which are enclosed within an ovary. Gymnosperm seeds develop either on the surface of scales or leaves, which are often modified to form cones, or solitary as in Yew, Torreya, Ginkgo.
The gymnosperms and angiosperms together compose the spermatophytes or seed plants. The gymnosperms are divided into six phyla. Organisms that belong to the Cycadophyta, Ginkgophyta, Gnetophyta, and Pinophyta (also known as Coniferophyta) phyla are still in existence while those in the Pteridospermales and Cordaitales phyla are now extinct.
By far the largest group of living gymnosperms are the conifers (pines, cypresses, and relatives), followed by cycads, gnetophytes (Gnetum, Ephedra and Welwitschia), and Ginkgo biloba (a single living species). Roots in some genera have fungal association with roots in the form of micorrhiza(Pinus), while in some others(Cycas) small specialised roots called coralloid roots are associated with nitrogen fixing cyanobacteria.
Gnetum is a genus of gymnosperms, the sole genus in the family Gnetaceae and order Gnetales. They are tropical evergreen trees, shrubs and lianas. Unlike other gymnosperms, they possess vessel elements in the xylem. Some species have been proposed to have been the first plants to be insect-pollinated as their fossils occur in association with extinct pollinating scorpion flies. Molecular phylogenies based on nuclear and plastid sequences from most of the species indicate hybridization among some of the Southeast Asian species. Fossil-calibrated molecular-clocks suggest that the Gnetum lineages now found in Africa, South America and Southeast Asia are the result of ancient long-distance dispersal across seawater
The "Telome theory" of Walter Zimmermann (1930, 1952) is the most accepted theory that is based on fossil record and synthesizes the major steps in the evolution of vascular plants.
It describes how the primitive type of vascular plants developed from Rhynia like plants.
This ppt has been made by Xanthophyceae also known as yellow green algae. It occupies second position in algae classification by F.E Fritsch. It is classified into four orders. It contain xanthophyll in large amount that gives it yellow colour, hence it is commonly know as yellow green algae.
Match the stele-type with its description.ProtosteleSiphonostele.pdfdhavalbl38
Match the stele-type with its description.
Protostele
Siphonostele
Eustele
Dispersed stele
The xylem forms an uninterrupted cylinder within a cylinder of phloem; found in the stems of
very simple seedless vascular plants.
A cylinder of phloem surrounds a cylinder of xylem which surrounds another cylinder of
phloem, with a pith of parenchyma cells at the center; found in the stems of ferns and fern allies.
The stele is broken into vascular bundles that are arranged in a ring with the phloem on the
outside and the xylem on the inside; commonly found in gymnosperms and dicots.
The stele is broken into vascular bundles that are scattered in cross section so that the orientation
of xylem and phloem is inconsistent from vascular bundle to vascular bundle; found in
monocots. - A. B. C. D.
Protostele - A. B. C. D.
Siphonostele - A. B. C. D.
Eustele - A. B. C. D.
Dispersed steleA.
The xylem forms an uninterrupted cylinder within a cylinder of phloem; found in the stems of
very simple seedless vascular plants.B.
A cylinder of phloem surrounds a cylinder of xylem which surrounds another cylinder of
phloem, with a pith of parenchyma cells at the center; found in the stems of ferns and fern
allies.C.
The stele is broken into vascular bundles that are arranged in a ring with the phloem on the
outside and the xylem on the inside; commonly found in gymnosperms and dicots.D.
The stele is broken into vascular bundles that are scattered in cross section so that the orientation
of xylem and phloem is inconsistent from vascular bundle to vascular bundle; found in
monocots.
Solution
A). The xylem forms an uninterrupted cylinder within a cylinder of phloem; found in the stems
of very simple seedless vascular plants. ---> Protostele
B). A cylinder of phloem surrounds a cylinder of xylem which surrounds another cylinder of
phloem, with a pith of parenchyma cells at the center; found in the stems of ferns and fern allies.
---> Siphonostele
C). The stele is broken into vascular bundles that are arranged in a ring with the phloem on the
outside and the xylem on the inside; commonly found in gymnosperms and dicots. ----> Eustele
D). The stele is broken into vascular bundles that are scattered in cross section so that the
orientation of xylem and phloem is inconsistent from vascular bundle to vascular bundle; found
in monocots ----> Dispersed stele.
Equisetum popularly known a the ‘horse-tail’ or ‘scouring rush’.
It is now represented by nearly 30 species which are seen world wide except in Australia and New Zealand.
Some species prefer damp and shady places while others grow in marshes, ponds or stream banks
Some are found in xerophytic habitats
The name Echinodermata is derived from two Greek words Echinos meaning spiny and Derma meaning skin, referring the spiny-skinned nature of animals.
Phylum Echinodermata is divisible into two groups on the basis of their habitat-
1. Eleutherozoans: They are characterised by the absence of stem and are free and mobile.
Example – echinoids.
2. Pelmatozoans: They have a stem that is attached to the ocean floor.
Typical Example – crinoids.
The echinoids are marine animals and belong to the Class Echinoidea. The name Echinoidea is derived from two Greek words Echinos meaning spines and Oidea meaning test, signifying the test covered with spines.
They include sea urchins, heart urchins and sand dollars.
The soft parts of the animal are enclosed inside a rigid calcareous skeleton, which is composed of many closely fitting plates of calcite. The skeleton of echinoids is also known as test
(Fig.). The tests may be spherical, globular, discoidal or heart-shaped and covered with spines. Most of the echinoids show pentameral (five-fold) radial symmetry whereas a few others show bilateral symmetry. The tests of echinoids range in size from 3 to 10 cm in diameter or length.
Echinoids can be divided into two main groups: regular and irregular.
Regular or Endocyclic Echinoids: They have five-fold (pentameral) radial symmetry and spherical to circular body.
Irregular or Exocyclic Echinoids: They have bilateral symmetry and a heart-shaped body.
The plant body in algae is always a thallus. It is not differentiated in root, stem and leaves. Algae range in size from minute unicellular plants (less than 1 µ in diameter in some planktons) to very large highly differentiated multicellular forms e.g., some sea-weeds.
Their forms may be colonial (loose or integrated by inter-connections of protoplasmic strands), filamentous (branched or un-branched), septate (branched or un-branched), non-septate or branched, multinucleate siphonaceous tube where the nuclear divisions occur without usual septa formation.
This is the report I made I uploaded it because i thought
it could be of help to those people who are looking for a simpler Fun Power Point...
it's coverages are
The cell history
the cell theory
Prokaryotic vs Eukaryotic
it doesnt have the cell structure
because my classmate
didnt gave me his report
and this is like introduction of the cell
:)
Similar to Stelar System, Stele, its types and evolution(edited) (20)
Coronaviruses & COVID 19 - Its Morphology, Role, Mechanism of Action, and Tre...Haider Ali Malik
Coronaviruses (CoV) are a large family of viruses transmitting between animals and people that cause illness ranging from the common cold to more severe diseases such as Middle East respiratory syndrome (MERS-CoV) and severe acute respiratory syndrome (SARS-CoV).
COVID-19 is a respiratory illness caused by a newly identified coronavirus, SARS-CoV-2
The current COVID-19 outbreak originated in Wuhan, China, in late 2019. World Health Organization (WHO) has been to characterized the outbreak as a pandemic on 11 March 2020. (WHO Bulletin 2020)
Heavy metals and its effects on plants and environmentHaider Ali Malik
Heavy metals are natural constituents of the earth’s crust , but indiscriminate human activities have drastically altered their geochemical cycles and biochemicals balance.
Any toxic metals may be called heavy metals.
Since heavy metals have a propensity to accumulate in selective body organs.
The average safety levels in food or water are often misleading high.
Heavy is any metal or metalloid of environmental concern.
Heavy metals are metallic element that have relatively high density usually greater than 5 g/cm3, or their density is greater than the density of water.
Modern Medical Application methodologies: Brachytherapy, Neutron Capture Ther...Haider Ali Malik
Brachytherapy (also referred to as Curie therapy) is defined as a short-distance treatment of malignant disease with radiation emanating from small sealed (encapsulated)
Neutron capture therapy (NCT) is a nonsurgical therapeutic modality for treating locally invasive malignant tumors such as primary brain tumors, and recurrent head and neck cancer.
Proton therapy, or proton radiotherapy, is a type of particle therapy that uses a beam of protons to irradiate diseased tissue, most often to treat cancer.
The USEPA defines biodegradation as a process by which microbial organisms transform or alter (through metabolic or enzymatic action) the structure of chemicals introduced into the environment.
According to the definition by the International Union of Pure and Applied Chemistry, the term biodegradation is “Breakdown of a substance catalyzed by enzymes in vitro or in vivo.
The term is often used in relation to ecology, waste management, biomedicine, and the natural environment (bioremediation) and is now commonly associated with environmentally friendly products that are capable of decomposing back into natural elements.
Biodegradable matter is generally organic material such as plant and animal matter and other substances originating from living organisms, or artificial materials that are similar enough to plant and animal matter to be put to use by microorganisms.
Phytoextraction, also called phytoaccumulation, phytoabsorption, or phytosequestration, refers to the use of plants to absorb, translocate, and store toxic contaminants from soil, sediments, and/or sludge in the root and shoot tissues .
Lead is an extremely difficult soil contaminant to remediate because it is a “soft” Lewis acid that forms strong bonds to both organic and inorganic ligands in soil. For the most part, Pb-contaminated soils are remediated through civil engineering techniques that require the excavation and landfilling of the contaminated soil. Soils that present a leaching hazard in the landfill are either placed in a specially constructed hazardous waste landfill, or treated with stabilizing agents, such as cement, prior to disposal in an industrial landfill.
Plants have adaptations to help them survive (live and grow) in different areas. Adaptations are special features that allow a plant or animal to live in a particular place or habitat. These adaptations might make it very difficult for the plant to survive in a different place.
This explains why certain plants are found in one area, but not in another. For example, you wouldn't see a cactus living in the Arctic. Nor would you see lots of really tall trees living in grasslands.
This presentation focuses on anatomical adaptations of three major types of plants: Hydrophytes, mesophytes and xerophytes.
Abiotic stress factors or stressors are naturally occurring, often intangible factors
The four major abiotic stresses: drought , salinity, temperature and heavy metals, cause drastic yield reduction in most crops.
Few of the types of abiotic stresses are:
1)Water-logging & drought
2)Excessive soil salinity
3)High or low temperatures
4)Ozone
5)Low oxygen
6)Phytotoxic compounds
8)Inadequate mineral in the soil
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This presentation focuses on the adaptations in plants against abiotic stress and the ways that how they tolerate it with different mechanisms.
- Haider Ali Malik
Osmoregulation is the passive regulation of the osmotic pressure of an organism's body fluids, detected by osmoreceptors, to maintain the homeostasis of the organism's water content; that is, it maintains the fluid balance and the concentration of electrolytes (salts in solution) to keep the fluids from becoming too diluted or concentrated.
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Protein targeting or protein sorting is the mechanism by which a cell transports to the appropriate positions in the cell or outside of it. Both in prokaryotes and eukaryotes, newly synthesized proteins must be delivered to a specific sub-cellular location or exported from the cell for correct activity. This phenomenon is called protein targeting. Protein targeting is necessary for proteins that are destined to work outside the cytoplasm.This delivery process is carried out based on information contained in the protein itself. Correct sorting is crucial for the cell; errors can lead to diseases. In 1970, Günter Blobel conducted experiments on the translocation of proteins across membranes. He was awarded the 1999 Nobel Prize for his findings. He discovered that many proteins have a signal sequence, that is, a short amino acid sequence at one end that functions like a postal code for the target organelle.
Mushrooms are nature's hidden treasures of nutrition. Many people like them for their satisfying meaty taste and their versatility. But are they really good for you? The answer is yes! In fact, you will be surprised to learn about the nutritional benefits of mushrooms. For thousands of years, mushrooms have been used in eastern medicine for their various health benefits.
The Shoot apex is also known as the terminal bud of plants that grows from 0.1-1.0 mm and consists of the apical meristem, developing leaves and the immediate surrounding leaf primordial. The shoot apex is present in both dicot and monocot plants.
Visit https://www.slideshare.net/alihaider408/stress-and-osmoregulation-in-plantsedited for new edited version of the slide.
Osmoregulation is the passive regulation of the osmotic pressure of an organism's body fluids, detected by osmoreceptors, to maintain the homeostasis of the organism's water content; that is, it maintains the fluid balance and the concentration of electrolytes (salts in solution) to keep the fluids from becoming too diluted or concentrated.
The immediate and most common response by the different organs of a plant to water stress is decrease in turgor. This may be partially or fully adjusted by accumulation of solutes.
The internet is the place where people around the world share information.
Addiction is the continued repetition of behavior despite adverse consequences leading to such behaviors.
A mobile phone is an electronic device used to make mobile telephone calls across a wide geographic area
In addition to being a telephone , modern mobile phones also support many additional services such as SMS, e-mail, internet access, gaming, Bluetooth, infrared, camera, MMS messaging, MP3 player, radio and GPS
Mobile phones were first developed in 1946
Multimedia is a computer-based interactive communications process that incorporates text, graphics, sound, animation, and video
The term is used in contrast to media which only use traditional forms of printed or hand-produced material.
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Computer cannot understanding our language because it understands only machine language and it can be possible using some devices are called input devices
Input device captures information and translates it into a form that can be processed and used by other parts of your computer
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Richard's entangled aventures in wonderlandRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
Cancer cell metabolism: special Reference to Lactate PathwayAADYARAJPANDEY1
Normal Cell Metabolism:
Cellular respiration describes the series of steps that cells use to break down sugar and other chemicals to get the energy we need to function.
Energy is stored in the bonds of glucose and when glucose is broken down, much of that energy is released.
Cell utilize energy in the form of ATP.
The first step of respiration is called glycolysis. In a series of steps, glycolysis breaks glucose into two smaller molecules - a chemical called pyruvate. A small amount of ATP is formed during this process.
Most healthy cells continue the breakdown in a second process, called the Kreb's cycle. The Kreb's cycle allows cells to “burn” the pyruvates made in glycolysis to get more ATP.
The last step in the breakdown of glucose is called oxidative phosphorylation (Ox-Phos).
It takes place in specialized cell structures called mitochondria. This process produces a large amount of ATP. Importantly, cells need oxygen to complete oxidative phosphorylation.
If a cell completes only glycolysis, only 2 molecules of ATP are made per glucose. However, if the cell completes the entire respiration process (glycolysis - Kreb's - oxidative phosphorylation), about 36 molecules of ATP are created, giving it much more energy to use.
IN CANCER CELL:
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
introduction to WARBERG PHENOMENA:
WARBURG EFFECT Usually, cancer cells are highly glycolytic (glucose addiction) and take up more glucose than do normal cells from outside.
Otto Heinrich Warburg (; 8 October 1883 – 1 August 1970) In 1931 was awarded the Nobel Prize in Physiology for his "discovery of the nature and mode of action of the respiratory enzyme.
WARNBURG EFFECT : cancer cells under aerobic (well-oxygenated) conditions to metabolize glucose to lactate (aerobic glycolysis) is known as the Warburg effect. Warburg made the observation that tumor slices consume glucose and secrete lactate at a higher rate than normal tissues.
Nutraceutical market, scope and growth: Herbal drug technologyLokesh Patil
As consumer awareness of health and wellness rises, the nutraceutical market—which includes goods like functional meals, drinks, and dietary supplements that provide health advantages beyond basic nutrition—is growing significantly. As healthcare expenses rise, the population ages, and people want natural and preventative health solutions more and more, this industry is increasing quickly. Further driving market expansion are product formulation innovations and the use of cutting-edge technology for customized nutrition. With its worldwide reach, the nutraceutical industry is expected to keep growing and provide significant chances for research and investment in a number of categories, including vitamins, minerals, probiotics, and herbal supplements.
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
Slide 1: Title Slide
Extrachromosomal Inheritance
Slide 2: Introduction to Extrachromosomal Inheritance
Definition: Extrachromosomal inheritance refers to the transmission of genetic material that is not found within the nucleus.
Key Components: Involves genes located in mitochondria, chloroplasts, and plasmids.
Slide 3: Mitochondrial Inheritance
Mitochondria: Organelles responsible for energy production.
Mitochondrial DNA (mtDNA): Circular DNA molecule found in mitochondria.
Inheritance Pattern: Maternally inherited, meaning it is passed from mothers to all their offspring.
Diseases: Examples include Leber’s hereditary optic neuropathy (LHON) and mitochondrial myopathy.
Slide 4: Chloroplast Inheritance
Chloroplasts: Organelles responsible for photosynthesis in plants.
Chloroplast DNA (cpDNA): Circular DNA molecule found in chloroplasts.
Inheritance Pattern: Often maternally inherited in most plants, but can vary in some species.
Examples: Variegation in plants, where leaf color patterns are determined by chloroplast DNA.
Slide 5: Plasmid Inheritance
Plasmids: Small, circular DNA molecules found in bacteria and some eukaryotes.
Features: Can carry antibiotic resistance genes and can be transferred between cells through processes like conjugation.
Significance: Important in biotechnology for gene cloning and genetic engineering.
Slide 6: Mechanisms of Extrachromosomal Inheritance
Non-Mendelian Patterns: Do not follow Mendel’s laws of inheritance.
Cytoplasmic Segregation: During cell division, organelles like mitochondria and chloroplasts are randomly distributed to daughter cells.
Heteroplasmy: Presence of more than one type of organellar genome within a cell, leading to variation in expression.
Slide 7: Examples of Extrachromosomal Inheritance
Four O’clock Plant (Mirabilis jalapa): Shows variegated leaves due to different cpDNA in leaf cells.
Petite Mutants in Yeast: Result from mutations in mitochondrial DNA affecting respiration.
Slide 8: Importance of Extrachromosomal Inheritance
Evolution: Provides insight into the evolution of eukaryotic cells.
Medicine: Understanding mitochondrial inheritance helps in diagnosing and treating mitochondrial diseases.
Agriculture: Chloroplast inheritance can be used in plant breeding and genetic modification.
Slide 9: Recent Research and Advances
Gene Editing: Techniques like CRISPR-Cas9 are being used to edit mitochondrial and chloroplast DNA.
Therapies: Development of mitochondrial replacement therapy (MRT) for preventing mitochondrial diseases.
Slide 10: Conclusion
Summary: Extrachromosomal inheritance involves the transmission of genetic material outside the nucleus and plays a crucial role in genetics, medicine, and biotechnology.
Future Directions: Continued research and technological advancements hold promise for new treatments and applications.
Slide 11: Questions and Discussion
Invite Audience: Open the floor for any questions or further discussion on the topic.
Introduction:
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is an important biological process for modulating eukaryotic gene expression.
It is highly conserved process of posttranscriptional gene silencing by which double stranded RNA (dsRNA) causes sequence-specific degradation of mRNA sequences.
dsRNA-induced gene silencing (RNAi) is reported in a wide range of eukaryotes ranging from worms, insects, mammals and plants.
This process mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes.
What are small ncRNAs?
micro RNA (miRNA)
short interfering RNA (siRNA)
Properties of small non-coding RNA:
Involved in silencing mRNA transcripts.
Called “small” because they are usually only about 21-24 nucleotides long.
Synthesized by first cutting up longer precursor sequences (like the 61nt one that Lee discovered).
Silence an mRNA by base pairing with some sequence on the mRNA.
Discovery of siRNA?
The first small RNA:
In 1993 Rosalind Lee (Victor Ambros lab) was studying a non- coding gene in C. elegans, lin-4, that was involved in silencing of another gene, lin-14, at the appropriate time in the
development of the worm C. elegans.
Two small transcripts of lin-4 (22nt and 61nt) were found to be complementary to a sequence in the 3' UTR of lin-14.
Because lin-4 encoded no protein, she deduced that it must be these transcripts that are causing the silencing by RNA-RNA interactions.
Types of RNAi ( non coding RNA)
MiRNA
Length (23-25 nt)
Trans acting
Binds with target MRNA in mismatch
Translation inhibition
Si RNA
Length 21 nt.
Cis acting
Bind with target Mrna in perfect complementary sequence
Piwi-RNA
Length ; 25 to 36 nt.
Expressed in Germ Cells
Regulates trnasposomes activity
MECHANISM OF RNAI:
First the double-stranded RNA teams up with a protein complex named Dicer, which cuts the long RNA into short pieces.
Then another protein complex called RISC (RNA-induced silencing complex) discards one of the two RNA strands.
The RISC-docked, single-stranded RNA then pairs with the homologous mRNA and destroys it.
THE RISC COMPLEX:
RISC is large(>500kD) RNA multi- protein Binding complex which triggers MRNA degradation in response to MRNA
Unwinding of double stranded Si RNA by ATP independent Helicase
Active component of RISC is Ago proteins( ENDONUCLEASE) which cleave target MRNA.
DICER: endonuclease (RNase Family III)
Argonaute: Central Component of the RNA-Induced Silencing Complex (RISC)
One strand of the dsRNA produced by Dicer is retained in the RISC complex in association with Argonaute
ARGONAUTE PROTEIN :
1.PAZ(PIWI/Argonaute/ Zwille)- Recognition of target MRNA
2.PIWI (p-element induced wimpy Testis)- breaks Phosphodiester bond of mRNA.)RNAse H activity.
MiRNA:
The Double-stranded RNAs are naturally produced in eukaryotic cells during development, and they have a key role in regulating gene expression .
Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...University of Maribor
Slides from:
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Track: Artificial Intelligence
https://www.etran.rs/2024/en/home-english/
Deep Behavioral Phenotyping in Systems Neuroscience for Functional Atlasing a...Ana Luísa Pinho
Functional Magnetic Resonance Imaging (fMRI) provides means to characterize brain activations in response to behavior. However, cognitive neuroscience has been limited to group-level effects referring to the performance of specific tasks. To obtain the functional profile of elementary cognitive mechanisms, the combination of brain responses to many tasks is required. Yet, to date, both structural atlases and parcellation-based activations do not fully account for cognitive function and still present several limitations. Further, they do not adapt overall to individual characteristics. In this talk, I will give an account of deep-behavioral phenotyping strategies, namely data-driven methods in large task-fMRI datasets, to optimize functional brain-data collection and improve inference of effects-of-interest related to mental processes. Key to this approach is the employment of fast multi-functional paradigms rich on features that can be well parametrized and, consequently, facilitate the creation of psycho-physiological constructs to be modelled with imaging data. Particular emphasis will be given to music stimuli when studying high-order cognitive mechanisms, due to their ecological nature and quality to enable complex behavior compounded by discrete entities. I will also discuss how deep-behavioral phenotyping and individualized models applied to neuroimaging data can better account for the subject-specific organization of domain-general cognitive systems in the human brain. Finally, the accumulation of functional brain signatures brings the possibility to clarify relationships among tasks and create a univocal link between brain systems and mental functions through: (1) the development of ontologies proposing an organization of cognitive processes; and (2) brain-network taxonomies describing functional specialization. To this end, tools to improve commensurability in cognitive science are necessary, such as public repositories, ontology-based platforms and automated meta-analysis tools. I will thus discuss some brain-atlasing resources currently under development, and their applicability in cognitive as well as clinical neuroscience.
2. Definition of Stelar System:
– According to the older botanists, the vascular bundle is
the fundamental unit in the vascular system of
pteridophytes and higher plants. Van Tieghem and
Douliot (1886) interpreted the plant body of vascular
plant in the different way.
– According to them, the fundamental parts of a shoot are
the cortex and a central cylinder, is known as stele. Thus
the stele is defined as a central vascular cylinder, with or
without pith and delimited the cortex by endodermis.
2
3. – The term stele has been derived from a Greek word
meaning pillar.
– Van Tieghem and Douliot (1886) recognized only three
types of steles.
1) Protostele
2) Siphonostele
3) Solenostele
– Some authors recognize only two kinds of
stele(protostele and siphonostele) and consider
solenostele as a sub-categorie of siphonostele.
3
4. Stelar Theory
It was proposed by Van Tieghem and Douliot
in1886.
Major highlights of stellar theory are:
Stele is a real entity and present universally in all
higher plants.
Cortex and stele are two fundamental parts of a
shoot system
Stele and cortex are separated by endodermis.
4
6. Types of Steles:6
1. Protostele:
Jeffrey (1898), for the first time pointed out the stelar
theory from the point of view of the phylogeny.
According to him, the primitive type of stele is
protostele.
In protostele, the vascular tissue is a solid mass and the
central core of the xylem is completely surrounded by
the strand of phloem.
This is the most primitive and simplest type of stellar
organization.
Pith is absent.
8. Forms of Protostele
There are several forms of protostele:
(a) Haplostele:
– This is the most primitive type of protostele.
– Named by Brebner in 1902
– Here the central solid smooth core of xylem remains surrounded by
phloem (e.g., in Selaginella spp., Rhynia).
(b) Actinostele:
– This is the modification of the haplostele and somewhat more
advanced in having the central xylem core with radiating ribs.
– A protostele in which xylem appears as stellate or star shaped with
many radiating arms in transverse section and phloem is present in
small patches in between the radiating arms of the xylem is known
as actinostele (e.g., in Psilotum spp. , lycopodium).
8
10. (c) Plectostele:
– This is the most advanced type of protostele.
– Here the central core of xylem is divided into number of plates
arranged parallel to each other. The phloem alternates the xylem.
– Zimmermann (1930) called such stele as plectostele e.g., Lycopodium
(d) Mixed-pith stele:
– Here the xylem elements (i.e., tracheids) are mixed with the
parenchymatous cells of the pith.
– This type is found in primitive fossils and living ferns.
– They are treated to be the transitional types in between true
protosteles on the one hand and siphonosteles on the other (e.g., in
Gleichenia spp. and Osmunda spp.).
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13. 2. Siphonostele:
– This is the modification of protostele.
– A stele with central pith surrounded by vascular tissue is
called siphonostele or a medullated protostele is called
siphonostele.
– Such stele contains a tubular vascular region and a
parenchymatous central region.
– Jeffrey (1898) interpreted that the vascular portion of
siphonostele possesses a parenchymatous area known as
a gap immediately above the branch traces only or
immediately above leaf and branch traces.
13
14. – On the basis of these branch and leaf gaps Jeffrey (1910),
distinguished two types of siphonosteles.
– In one type, however, the leaf gaps are not found and they
are known as cladosiphonic siphonosteles.
– In the other type both leaf and branch gaps are present and
they are known as phyllosiphonic siphonosteles.
14
16. Types of Siphonostele
– A siphonostele may be of the following types:
16
Ectophloic Amphiphloic
17. (a) Ectophloic siphonostele:
– In this type of siphonostele, the pith is surrounded by concentric
xylem cylinder and next to xylem the concentric phloem cylinder.
– Phloem is present only external to the xylem (Fig. 3A) e.g.,
Osmunda, Schizaea.
(b) Amphiphloic siphonostele:
– In this type of siphonostele the pith is surrounded by the vascular
tissue. The concentric inner phloem cylinder surrounds the central
pith.
– Next to the inner phloem is the concentric xylem cylinder which is
immediately surrounded by outer phloem cylinder (e.g., in
Marsilea).
17
20. Evolution of Siphonostele from
Protostele:
There are two main theories regarding the evolution of siphonostele from
protostele:
(a) Intraxylary or Intrastelar origin:
According to this theory the siphonostele is evolved by the conversion of the
central mass of the xylem into parenchymatous pith.
This theory is also known as expansion theory and it is supported by Boodle
(1901), Bower (1911), Gwynne-Vaughan (1903, 1914). Petry (1914), Thompson
and Gewirtz and Fahn (1960) etc.
(b) Extrastelar Origin:
This theory is supported by Jaffery (1897, 1899, 1902, 1917). According to him
the pith is originated as a result of invasion of the parenchymatous cells of the
cortex into the stele.
It takes place through the leaf gaps and branch gaps. This theory is also known
as invasion theory.
20
21. (c) Solenostele:
– The siphonostele which is perforated by
scattered leaf traces is known as solenostele
(Gwynne-Vaughan, 1907; Schoulte, 1938).
– In simple words, siphonostele with leaf gap is
called solenostele
– It is actually a sub categorie of siphonostele.
21
26. Types of Solenostele26
(i) Ectophlopic solenostele:
•Phloem is present only on outer
side
•e.g. Nicotiana & Salix .
(ii) Amphiphloic solenostele:
•Phloem is present on both the
sides of the xylem
•e.g Adiantum, Marsilea
28. Dictyostele:
– A solenostele with more overlapping leaf gaps so as to show more
than interruption in one transverse section is known as dissected
siphonostele or dissected solenostele or dictyostele.
– It is broken into network of separate vascular bundles.
– Brebner (1902) called the siphonosteles with overlapping gaps as
dictyosteles.
– The vascular parts of dictyostele between the neighbouring leaf
gaps are known as meristeles which are of protostelic type. The
dictyostele with many meristeles looks like a cylindrical meshwork.
– These vascular bundles are concentric (central xylem surrounded
by phloem, pericycle and endodermis), called meristeles (e.g.
Dryopteris).
28
30. Eustele:
– It is characteristic of Gymnosperms and dicots stem.
– In this type of stele collateral or bicollateral vascular bundles are
present in a ring (Brebner, 1902)
Atactostele:
– It is characteristic of monocots. In this type of stele vascular bundle
lies scattered in the (Brebner, 1902). It is the highly evolved stelar
organisation. ground tissue
– This is a special case of Eustele in which the stele is more disected
with leaf gaps, so that , in transverse section, the vascular bundles
are scattered though the fundamental tissue (e.g. Monocot stems,
Corn & Grasses).
30