Tocheri y colaboradores sostienen que las pruebas moleculares y fósiles tienen importantes consecuencias para la interpretación de la historia evolutiva de la mano dentro de la tribu Hominini. En primer lugar, la parsimonia apoya la hipótesis de que la mano del último ancestro común de los humanos y chimpancés es más probable que es pareciera a la de un gran simio actual en general (Pan, Gorilla, y Pongo), que a la de un simio africano en particular. En segundo lugar, proporciona un contexto para la interpretación de los cambios derivados de la mano que se han desarrollado en diferentes homínidos. Sin embargo, la mayoría de las características primitivas que es probable que estuvieran presentes en el último ancestro común de Pan y Homo se mantienen en las manos de Australopithecus, Paranthropus/primeros humanos, y Homo floresiensis.
Análisis de las proporciones internas de la mano (la longitud de los huesos largos del pulgar y el cuarto dedo) en relación con el tamaño corporal de una muestra de primates actuales y extintos. La muestra la conforma un total de 274 primates entre los que se incluyen macacos, mandriles, gibones, orangutanes, gorilas, chimpancés y Homo sapiens; además de algunas especies extintas de homininos (Ardipithecus ramidus, Australopithecus sediba y Homo neanderthalensis).
The authors report the discovery of Lomekwi 3, a 3.3-million-year-old archaeological site where in situ stone artefacts occur in spatiotemporal association with Pliocene hominin fossils in a wooded palaeoenvironment.
El principal objetivo de este trabajo ha consistido en establecer una cronología y datación precisas de los yacimientos Musterienses de Eurasia, ya que éstos contienen las mejores pruebas de la sustitución de un grupo humano (los Neandertales) por otro (AMHs)
Human evolution is the lengthy process of change by which people originated from apelike ancestors. Scientific evidence shows that the physical and behavioral traits shared by all people originated from apelike ancestors and evolved over a period of approximately six million years.
Análisis de las proporciones internas de la mano (la longitud de los huesos largos del pulgar y el cuarto dedo) en relación con el tamaño corporal de una muestra de primates actuales y extintos. La muestra la conforma un total de 274 primates entre los que se incluyen macacos, mandriles, gibones, orangutanes, gorilas, chimpancés y Homo sapiens; además de algunas especies extintas de homininos (Ardipithecus ramidus, Australopithecus sediba y Homo neanderthalensis).
The authors report the discovery of Lomekwi 3, a 3.3-million-year-old archaeological site where in situ stone artefacts occur in spatiotemporal association with Pliocene hominin fossils in a wooded palaeoenvironment.
El principal objetivo de este trabajo ha consistido en establecer una cronología y datación precisas de los yacimientos Musterienses de Eurasia, ya que éstos contienen las mejores pruebas de la sustitución de un grupo humano (los Neandertales) por otro (AMHs)
Human evolution is the lengthy process of change by which people originated from apelike ancestors. Scientific evidence shows that the physical and behavioral traits shared by all people originated from apelike ancestors and evolved over a period of approximately six million years.
La difusión histórica del camote, la patata dulce.
La Kumara, el camote peruano llegó a Nueva Zelanda en tiempos precolombinos. Enlace: https://www.pnas.org/content/110/6/2205
Humans are an incredibly different species, mostly separated from the rest of the world’s inhabitants. Apart from language and intelligence, humans have unique social traditions. One example is the burial of the dead. While there are reports of several animals performing ‘funerals’ for their deceased, no other species perform ritualistic burials the way humans do.
Sex determination in booted eagles (Hieraaetus pennatus) using molecular procedures and discriminant function analysis. Journal of Raptor Research, 35 (1): 20-23.
Jack corbo presentation on the population genetics of chelydra serpentina (no...Jack Corbo
Prior research the North American turtle species, Chelydra serpentina (North American Snapping Turtle), has produced an unanticipated observation. There is low variability in the normally hypervariable displacement loop (d-loop) of the control region (CR) mitochondrial (mt)DNA. Paleoclimatic data was used to qualitatively investigate the causes for the lack of genetic variation observed in C. serpentina. For comparison, similar investigations were made on the ranges of two understudied related species, Chelydra rossignonii (Mexican Snapping Turtle) and Chelydra acutirostris (South American Snapping Turtle). A series of Pleistocene bottlenecks caused by a southward climatic shift in the 18˚C mean July temperature (apparently needed for egg incubation) and lethal marine transgressions over the Florida Peninsula related to interglacial transitions offer an explanation for the low genetic diversity of CR mtDNA found among C. serpentina populations. In contrast, the two Central and South American species both have Pleistocene glacial-interglacial refugia embedded within significant portions of their ranges. These climatically stable regions isolated the two species and promoted genetic divergence.
Video of presentation by Jack Corbo on my facebook page (www.facebook.com/jack.corbo.9)
Biodistances among Mexica, Maya, Toltec, and Totonac Groups of Central and Coastal Mexico
Las Distancias Biológicas entre los Mexicas, Mayas, Toltecas y Totonacas de México Central y Zona Costera
Cathy Willermet, Heather J.H. Edgar, Corey Ragsdale and B. Scott Aubry
Home Read Sign inEXPLORATIONSCONTENTS Search in boSusanaFurman449
Home Read Sign in
EXPLORATIONS
CONTENTS
Search in book …
Private: Main Body
9. Early Hominins
Kerryn Warren, Ph.D., University of Cape Town
Lindsay Hunter, Ph.D., University of Witwatersrand
Navashni Naidoo, M.Sc., University of Cape Town
Silindokuhle Mavuso, M.Sc., University of Witwatersrand
Kimberleigh Tommy, M.Sc., University of Witwatersrand
Rosa Moll, M.Sc., University of Witwatersrand
Nomawethu Hlazo, M.Sc., University of Cape Town
Learning Objectives
De�ne what is meant by “hominin”.
Understand what is meant by “derived” and “primitive” traits and why this is relevant for understanding early
hominin evolution.
Understand changing paleoclimates and paleoenvironments during early human evolution, and contextualize
them as potential factors in�uencing adaptations during this time.
Describe the anatomical changes associated with bipedalism in early hominins and the implications for
changes in locomotion.
Describe the anatomical changes associated with dentition in early hominins and their implication for diet in
the Plio-Pleistocene.
Describe early hominin genera and species, including their currently understood dates and geographic ex-
panses and what we know about them. Previous: Primate Evolution
Next: Early Members of the Genus Homo
https://pressbooks-dev.oer.hawaii.edu/
https://pressbooks-dev.oer.hawaii.edu/explorationsbioanth
https://pressbooks-dev.oer.hawaii.edu/explorationsbioanth/front-matter/__unknown__/
https://pressbooks-dev.oer.hawaii.edu/explorationsbioanth/wp-login.php?redirect_to=https%3A%2F%2Fpressbooks-dev.oer.hawaii.edu%2Fexplorationsbioanth%2Fchapter%2Fchapter-9-early-hominins-2%2F
https://pressbooks-dev.oer.hawaii.edu/explorationsbioanth/
https://pressbooks-dev.oer.hawaii.edu/explorationsbioanth/chapter/__unknown__-10/
https://pressbooks-dev.oer.hawaii.edu/explorationsbioanth/chapter/__unknown__-15/
Describe the earliest stone tool techno-complex and what it implies about the transition from early ho-
minins to our genus.
DEFINING HOMININS
It is through our study of our hominin ancestors and relatives that we are exposed to a world of “might have beens”: of
other paths not taken by our species, other ways of being human. But in order to better understand these different evolu-
tionary trajectories, we must �rst de�ne the terms we are using. If an imaginary line were drawn between ourselves and
our closest relatives, the great apes, bipedalism (or habitually walking upright on two feet) is where that line would be.
Hominin, then, means everyone on “our” side of the line: humans and all of our extinct bipedal ancestors and relatives
since our divergence from the last common ancestor (LCA) with chimpanzees.
Historic interpretations of our evolution, prior to our �nding of early hominin fossils, varied. Debates in the mid-1800s re-
garding hominin origins focused on two key issues:
���Where did we evolve?
���Which traits evolved �rst?
Charles Darwin hypothesized that we evolved ...
La difusión histórica del camote, la patata dulce.
La Kumara, el camote peruano llegó a Nueva Zelanda en tiempos precolombinos. Enlace: https://www.pnas.org/content/110/6/2205
Humans are an incredibly different species, mostly separated from the rest of the world’s inhabitants. Apart from language and intelligence, humans have unique social traditions. One example is the burial of the dead. While there are reports of several animals performing ‘funerals’ for their deceased, no other species perform ritualistic burials the way humans do.
Sex determination in booted eagles (Hieraaetus pennatus) using molecular procedures and discriminant function analysis. Journal of Raptor Research, 35 (1): 20-23.
Jack corbo presentation on the population genetics of chelydra serpentina (no...Jack Corbo
Prior research the North American turtle species, Chelydra serpentina (North American Snapping Turtle), has produced an unanticipated observation. There is low variability in the normally hypervariable displacement loop (d-loop) of the control region (CR) mitochondrial (mt)DNA. Paleoclimatic data was used to qualitatively investigate the causes for the lack of genetic variation observed in C. serpentina. For comparison, similar investigations were made on the ranges of two understudied related species, Chelydra rossignonii (Mexican Snapping Turtle) and Chelydra acutirostris (South American Snapping Turtle). A series of Pleistocene bottlenecks caused by a southward climatic shift in the 18˚C mean July temperature (apparently needed for egg incubation) and lethal marine transgressions over the Florida Peninsula related to interglacial transitions offer an explanation for the low genetic diversity of CR mtDNA found among C. serpentina populations. In contrast, the two Central and South American species both have Pleistocene glacial-interglacial refugia embedded within significant portions of their ranges. These climatically stable regions isolated the two species and promoted genetic divergence.
Video of presentation by Jack Corbo on my facebook page (www.facebook.com/jack.corbo.9)
Biodistances among Mexica, Maya, Toltec, and Totonac Groups of Central and Coastal Mexico
Las Distancias Biológicas entre los Mexicas, Mayas, Toltecas y Totonacas de México Central y Zona Costera
Cathy Willermet, Heather J.H. Edgar, Corey Ragsdale and B. Scott Aubry
Home Read Sign inEXPLORATIONSCONTENTS Search in boSusanaFurman449
Home Read Sign in
EXPLORATIONS
CONTENTS
Search in book …
Private: Main Body
9. Early Hominins
Kerryn Warren, Ph.D., University of Cape Town
Lindsay Hunter, Ph.D., University of Witwatersrand
Navashni Naidoo, M.Sc., University of Cape Town
Silindokuhle Mavuso, M.Sc., University of Witwatersrand
Kimberleigh Tommy, M.Sc., University of Witwatersrand
Rosa Moll, M.Sc., University of Witwatersrand
Nomawethu Hlazo, M.Sc., University of Cape Town
Learning Objectives
De�ne what is meant by “hominin”.
Understand what is meant by “derived” and “primitive” traits and why this is relevant for understanding early
hominin evolution.
Understand changing paleoclimates and paleoenvironments during early human evolution, and contextualize
them as potential factors in�uencing adaptations during this time.
Describe the anatomical changes associated with bipedalism in early hominins and the implications for
changes in locomotion.
Describe the anatomical changes associated with dentition in early hominins and their implication for diet in
the Plio-Pleistocene.
Describe early hominin genera and species, including their currently understood dates and geographic ex-
panses and what we know about them. Previous: Primate Evolution
Next: Early Members of the Genus Homo
https://pressbooks-dev.oer.hawaii.edu/
https://pressbooks-dev.oer.hawaii.edu/explorationsbioanth
https://pressbooks-dev.oer.hawaii.edu/explorationsbioanth/front-matter/__unknown__/
https://pressbooks-dev.oer.hawaii.edu/explorationsbioanth/wp-login.php?redirect_to=https%3A%2F%2Fpressbooks-dev.oer.hawaii.edu%2Fexplorationsbioanth%2Fchapter%2Fchapter-9-early-hominins-2%2F
https://pressbooks-dev.oer.hawaii.edu/explorationsbioanth/
https://pressbooks-dev.oer.hawaii.edu/explorationsbioanth/chapter/__unknown__-10/
https://pressbooks-dev.oer.hawaii.edu/explorationsbioanth/chapter/__unknown__-15/
Describe the earliest stone tool techno-complex and what it implies about the transition from early ho-
minins to our genus.
DEFINING HOMININS
It is through our study of our hominin ancestors and relatives that we are exposed to a world of “might have beens”: of
other paths not taken by our species, other ways of being human. But in order to better understand these different evolu-
tionary trajectories, we must �rst de�ne the terms we are using. If an imaginary line were drawn between ourselves and
our closest relatives, the great apes, bipedalism (or habitually walking upright on two feet) is where that line would be.
Hominin, then, means everyone on “our” side of the line: humans and all of our extinct bipedal ancestors and relatives
since our divergence from the last common ancestor (LCA) with chimpanzees.
Historic interpretations of our evolution, prior to our �nding of early hominin fossils, varied. Debates in the mid-1800s re-
garding hominin origins focused on two key issues:
���Where did we evolve?
���Which traits evolved �rst?
Charles Darwin hypothesized that we evolved ...
MUSEUM OF NATURAL HISTORY PUBLICATION FOR EDUCATORSV.docxroushhsiu
MUSEUM OF NATURAL HISTORY PUBLICATION FOR EDUCATORS
VOLUME 31 NO. 1 SPRING 2010
WHAT DOES IT MEAN TO BE HUMAN?
A BEHAVIORAL PERSPECTIVE
by Alison S. Brooks
˜ ˜ ˜
“…it would be impossible to fix on any point when the term “man”
ought to be used……” (Darwin 1871: 230)
A
new permanent exhibit at the Smithsonian’s Na
tional Museum of Natural History asks the ques
tion “What does it mean to be human?” Before
there were any fossils to inform us about the roads taken
and not taken on our evolutionary journey, 18th and 19th
century scholars wrestled with the anatomical similarities
between humans and apes, especially, as Darwin noted,
the African apes. Many of the human distinctions these
early scholars cited were behavioral, including language,
tool-making and technology-dependence, culture, use of
fire, a sense of shame, burial of the dead, and a sense of
the sacred. Even today, our anatomy alone may not suf-
fice to define our genus Homo. Indeed in 1964 one of the
oldest members of our genus, Homo habilis, was defined
as Homo to a large extent on the basis of the tools found
in association with its bones; the evolutionary or generic
status of the bones themselves remains controversial. As
in the museum’s new exhibit, new approaches to under-
standing our past and defining our species emphasize the
role of changing human behavior and its relationship to
and possible role in changing our anatomy.
This paper offers a brief summary of key discover-
ies in the fossil record followed by a discussion of be-
havioral characteristics defining modern humans and their
emergence through time. This is followed by a descrip-
tion of the evidence documenting the development of
archaic, Neanderthal, and modern humans, tracing the
evolution of key behaviors from 600 kya to 40 kya (thou-
sands of years ago). Finally, the evidence for the role of
Africa in the gradual evolution of distinctly modern hu-
man behaviors is argued as the paper concludes.
The Fossil Record of Human Evolution
Charles Darwin in his 1871 book, The Descent of Man,
located the likely origination of humans in Africa due to
the geographic distribution and comparable anatomy of
the chimpanzee and gorilla. Other early scholars, how-
ever, thought that our two most distinctive anatomical
features, our large brains and our two-legged gait, had
evolved together and that these changes had happened in
Europe. In Darwin’s time, only a few fossils of Nean-
SPECIAL ISSUE ON HUMAN ORIGINSSPECIAL ISSUE ON HUMAN ORIGINSSPECIAL ISSUE ON HUMAN ORIGINSSPECIAL ISSUE ON HUMAN ORIGINSSPECIAL ISSUE ON HUMAN ORIGINS
What Does it Mean to be Human?What Does it Mean to be Human?What Does it Mean to be Human?What Does it Mean to be Human?What Does it Mean to be Human?
ANTHRONOTES®
Page 2
AnthroNotes Volume 31 No.1 Spring 2010
derthals, our closest extinct relatives, had been recovered
from European sites. The 1891 finding in Java of Pithecan-
thropus erectus (now Homo erectus), an ...
Human evolution is the evolutionary process leading up to the appearance of modern humans. It is the process by which human beings developed on Earth from now-extinct primates. It involves the lengthy process of change by which people originated from apelike ancestors. The study of human evolution involves many scientific disciplines, including physical anthropology, primatology, archaeology, ethology, evolutionary psychology, embryology and genetics. Scientific evidence shows that the physical and behavioural traits shared by all people originated from apelike ancestors and evolved over a period of approximately six million years.
TABLE OF CONTENT
1.0 Introduction
2.0 Evolutionary Theory
3.0 Process of Evolution
4.0 History of Human Evolution
5.0 Paleoanthropology
6.0 Evidence of Evolution
6.1 Evidence from comparative physiology
6.2 Evidence from comparative anatomy
6.3 Evidence from comparative embryology
6.4 Evidence from comparative morphology
6.5 Evidence from vestigial organs
6.6 Genetics
6.7 Evidence from Molecular Biology
6.8 Evidence from the Fossil Record
7.0 Divergence of the Human Clade from other Great Apes
8.0 Anatomical changes
8.1 Anatomy of bipedalism
8.2 Encephalization
8.3 Sexual dimorphism
8.4 Other changes
9.0 Genus Homo
10.0 Homo Sapiens Taxonomy
Diapositivas de la charla que ofrecí sobre ciencia, arqueología y pensamiento crítico, en el marco de la segunda edición de las charlas Hablando de Ciencia en Málaga 2015
Recopilación de todos los resúmenes y comentarios que se han realizado en el blog Tertulias Literarias de Ciencia acerca del libro Mala Ciencia de Ben Goldacre
Se han hecho públicos los resultados de un prometedor trabajo encabezado por investigadores del Hospital Infantil de Boston y la Facultad de Medicina de Harvard, que ha conseguido recuperar, utilizando terapia génica, parte de la audición de ratones sordos. El artículo, que ha merecido la portada de la prestigiosa revista Science Translational Medicine, promete abrir un abanico terapéutico para el tratamiento de la sordera genética en los seres humanos.
Descripción del mecanismo de acción de la colchina en el tratamiento de la fiebre mediterránea familiar, y de los nuevos medicamentos que se están empleando para tratar esta dolencia.
Interleukin-1 targeting drugs in familial mediterranean fever: a case series ...José Luis Moreno Garvayo
Revisión de los artículos publicados que describen el uso de medicamentos cuyo objetivo es la interleucina-1 en el tratamiento de la fiebre mediterránea familiar. Se describen siete casos en todos los cuales el uso de estos medicamentos fue beneficioso.
Evidence based recommendations for the practical management of familial medit...José Luis Moreno Garvayo
Revisión de la literatura acerca de cuestiones prácticas en relación con la fiebre mediterránea familiar. Sobre la base del análisis de los artículos publicados se exponen las recomendaciones de los expertos tras la celebración de una reunión en Israel donde se expusieron todos los puntos de vista.
Este artículo muestra los resultados de un experimento con un test (llamado cognitive reflection test ―CRT por sus siglas en inglés y cuya traducción puede ser “prueba de reflexión cognitiva”) diseñado por Shane Frederick, profesor de mercadotecnia en la Universidad de Yale. Se realizaron una serie de encuestas a estudiantes de varias universidades norteamericanas (entre ellas el MIT, la Universidad de Princeton, Carnegie Mellon y Harvard) con el objetivo de averiguar qué tipo de razonamiento sigue una persona al enfrentarse a un problema en su vida cotidiana.
Guión de la charla que di en Málaga el pasado día 24 de octubre de 2014. En la cultura popular aún persiste la idea que el hombre desciende del chimpancé, esto es, que somos el hermano evolucionado de este simio. Con esta charla trato de corregir ese error mediante un breve repaso de los restos fósiles de nuestros antepasados y de cómo la teoría de la evolución explica cómo hemos llegado aquí.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
Spectroscopy is a branch of science dealing the study of interaction of electromagnetic radiation with matter.
Ultraviolet-visible spectroscopy refers to absorption spectroscopy or reflect spectroscopy in the UV-VIS spectral region.
Ultraviolet-visible spectroscopy is an analytical method that can measure the amount of light received by the analyte.
What is greenhouse gasses and how many gasses are there to affect the Earth.moosaasad1975
What are greenhouse gasses how they affect the earth and its environment what is the future of the environment and earth how the weather and the climate effects.
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.
(May 29th, 2024) Advancements in Intravital Microscopy- Insights for Preclini...Scintica Instrumentation
Intravital microscopy (IVM) is a powerful tool utilized to study cellular behavior over time and space in vivo. Much of our understanding of cell biology has been accomplished using various in vitro and ex vivo methods; however, these studies do not necessarily reflect the natural dynamics of biological processes. Unlike traditional cell culture or fixed tissue imaging, IVM allows for the ultra-fast high-resolution imaging of cellular processes over time and space and were studied in its natural environment. Real-time visualization of biological processes in the context of an intact organism helps maintain physiological relevance and provide insights into the progression of disease, response to treatments or developmental processes.
In this webinar we give an overview of advanced applications of the IVM system in preclinical research. IVIM technology is a provider of all-in-one intravital microscopy systems and solutions optimized for in vivo imaging of live animal models at sub-micron resolution. The system’s unique features and user-friendly software enables researchers to probe fast dynamic biological processes such as immune cell tracking, cell-cell interaction as well as vascularization and tumor metastasis with exceptional detail. This webinar will also give an overview of IVM being utilized in drug development, offering a view into the intricate interaction between drugs/nanoparticles and tissues in vivo and allows for the evaluation of therapeutic intervention in a variety of tissues and organs. This interdisciplinary collaboration continues to drive the advancements of novel therapeutic strategies.
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
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.
A brief information about the SCOP protein database used in bioinformatics.
The Structural Classification of Proteins (SCOP) database is a comprehensive and authoritative resource for the structural and evolutionary relationships of proteins. It provides a detailed and curated classification of protein structures, grouping them into families, superfamilies, and folds based on their structural and sequence similarities.
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.
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 .