The process of development involves mechanisms at the molecular, cellular and tissue levels to arrive at the complex anatomical and physiological structure of an organism. The study of development can shed light into the processes of many diseases and disorders that afflict people worldwide.
Reblogged from jewsee-medicalstudent  125 notes
jewsee-medicalstudent:

The death of a cell.
This picture is an amazing 3D illustration of apoptosis. The word “apoptosis” originates from Ancient Greek ἀπό, “away from” and πτῶσις, “falling” and it is a regulated process of cell death. 
There are two ways of cell death: necrosis and apoptosis. Necrosis is a form of traumatic cell death that results from acute cellular injury, and it usually causes inflammation, because of cell’s content released outside in the extracellular fluid. Apoptosis, on the other hand, could confer advantages during an organism’s lifecycle and it produces cell fragments called apoptotic bodies that phagocytic cells are able to engulf and quickly remove, before the cell’s content spills out onto surrounding cells, causing damage.
A cell initiates intracellular apoptotic signaling in response to a stress, which may bring about cell suicide. The binding of nuclear receptors by glucocorticoids, heat, radiation, nutrient deprivation, viral infection, hypoxia and increased intracellular calcium concentration, for example, by damage to the membrane, can all trigger the release of intracellular apoptotic signals by a damaged cell. 
Research in and around apoptosis has increased substantially since the early 1990s. In addition to its importance as a biological phenomenon, defective apoptotic processes have been implicated in an extensive variety of diseases. Excessive apoptosis causes atrophy, whereas an insufficient amount results in uncontrolled cell proliferation, such as cancer.
(Source).

jewsee-medicalstudent:

The death of a cell.

This picture is an amazing 3D illustration of apoptosis. The word “apoptosis” originates from Ancient Greek ἀπό, “away from” and πτῶσις, “falling” and it is a regulated process of cell death.

There are two ways of cell death: necrosis and apoptosis. Necrosis is a form of traumatic cell death that results from acute cellular injury, and it usually causes inflammation, because of cell’s content released outside in the extracellular fluid. Apoptosis, on the other hand, could confer advantages during an organism’s lifecycle and it produces cell fragments called apoptotic bodies that phagocytic cells are able to engulf and quickly remove, before the cell’s content spills out onto surrounding cells, causing damage.

A cell initiates intracellular apoptotic signaling in response to a stress, which may bring about cell suicide. The binding of nuclear receptors by glucocorticoids, heat, radiation, nutrient deprivation, viral infection, hypoxia and increased intracellular calcium concentration, for example, by damage to the membrane, can all trigger the release of intracellular apoptotic signals by a damaged cell. 

Research in and around apoptosis has increased substantially since the early 1990s. In addition to its importance as a biological phenomenon, defective apoptotic processes have been implicated in an extensive variety of diseases. Excessive apoptosis causes atrophy, whereas an insufficient amount results in uncontrolled cell proliferation, such as cancer.

(Source).

Females have penises in sex-reversed cave insects

Female insects with “penises” have been discovered in Brazil - the first example of an animal with sex-reversed genitalia, scientists say.

Neotrogla females insert the erectile organs into males’ vagina-like openings.

The elaborate structure, dubbed a “gynosome”, is used to suck out sperm and nutritious seminal fluids.

Copulation lasts an impressive 40-70 hours, the researchers report in Current Biology.

"Although sex-role reversal has been identified in several different animals, Neotrogla is the only example in which the intromittent organ is also reversed,” said lead author Kazunori Yoshizawa from Hokkaido University in Japan.

The gender-bending insects were found in a cave in eastern Brazil and represent four distinct species in the Neotrogla genus.  

Once inside a male, the membranous part of the female gynosome inflates. It has numerous spines which anchor the two insects together.

When the researchers attempted to pull a male and female apart, the male’s abdomen was ripped from the thorax without breaking the genital coupling.

The unusual role reversal may have been driven by the resource-poor cave environment in which the bugs live, the researchers speculate.

Copulation provides a female with food as well as sperm - so it is advantageous for her to mate at a higher rate, they note.

The curious insects offer new opportunities to test ideas about sexual selection, conflict between the sexes, and the evolution of novelty.

"It will be important to unveil why, among many sex-role-reversed animals, only Neotrogla evolved the elaborated female penis,” said Yoshitaka Kamimura from Keio University in Japan.

Their first task, they say, is to establish a healthy population of the insects in the lab.

Image 1: The erectile organ is inserted into males to suck out sperm and food

Image 2: The female is always on top during copulation - which lasts up to 70 hours

Image 3: A close-up of the insects in copulation

Source: BBC Science & Environment

MRSA Spreads in Households
Drug-resistant bacteria have found refuge in residences in parts of New York City


Genome sequencing has revealed how a strain of methicillin-resistant Staphylococcus aureus (MRSA) spread through parts of New York City. Although MRSA is often associated with public spaces such as hospital and gyms, researchers say that private homes helped to fuel its travels in the New York neighborhoods of Manhattan and the Bronx.
The study, published in the Proceedings of the National Academy of Sciences, suggests a framework for other investigations into how pathogens colonize and infect communities.
Researchers examined the prevalence of the USA300 strain in northern Manhattan and the Bronx, where it has caused an epidemic of skin and soft-tissue infections in recent years. In 2009, it was responsible for around 75% of community-acquired MRSA infections in northern Manhattan.
Anne-Catrin Uhlemann, a microbiologist at Columbia University Medical Center in New York, and her colleagues sequenced the genomes of 400 samples of MRSA collected from 161 people between 2009 and 2011, and compared them with samples from healthy people (many healthy people carry S. aureus bacteria, which could be MRSA). They also gathered data on study participants’ medical histories, antibiotic use and home locations to identify a network of USA300 transmission.
“This is an elegant and productive use of whole-genome sequencing in an epidemiological investigation,” says microbiologist Alexander Tomasz of the Rockefeller University in New York.
Evolving infectionUhlemann and her team estimated the similarity between MRSA samples by checking how many different single-nucleotide polymorphisms (SNPs) — single-letter changes in their genomes — they had, and working out how fast these changes accumulated. The researchers calculated that the USA300 strains diverged from their most recent common ancestor around 1993. Although 85% of the samples were closely related to two known reference USA300 genomes, others were more diverse.
The team found that some of the samples originated in California and Texas, suggesting that USA300 was introduced into New York multiple times, rather than having one local ancestor.
Samples from people in a single household tended to be more similar to each other than to samples from other households, which implies that individuals within a home frequently exchange S. aureus. But people were also getting infected outside the home: “There were some households where we found multiple kinds of USA300, which is quite surprising,” says Uhlemann. “It suggests some kind of outside reservoir, such as a link to a hospital or a gym.”It seems that the USA300 strain spread in public spaces first, but it is now prevalent in households as well as hospitals. Further studies are needed to evaluate how hospitals might be involved in spreading the bacteria back into the community, say the study authors.
Uhlemann and her colleagues also found that nearly two-thirds of their bacterial samples were either fully or partially resistant to fluoroquinolone antibiotics, which are often prescribed for routine bacterial infections. The drug gets excreted onto skin surfaces, which the authors suggest may have contributed to the resistance in USA300: the bacteria get exposed to low levels of the antibiotic and can evolve ways to survive it. “We have to limit our antibiotic use because the consequences may really be a lot of collateral damage,” says Uhlemann.
Image: MRSA bacteria (pink) of various types were found in New York households. Credit: NIAID
This article is reproduced with permission from the magazine Nature. Thearticle was first published on April 21, 2014.

MRSA Spreads in Households

Drug-resistant bacteria have found refuge in residences in parts of New York City

Genome sequencing has revealed how a strain of methicillin-resistant Staphylococcus aureus (MRSA) spread through parts of New York City. Although MRSA is often associated with public spaces such as hospital and gyms, researchers say that private homes helped to fuel its travels in the New York neighborhoods of Manhattan and the Bronx.

The study, published in the Proceedings of the National Academy of Sciences, suggests a framework for other investigations into how pathogens colonize and infect communities.

Researchers examined the prevalence of the USA300 strain in northern Manhattan and the Bronx, where it has caused an epidemic of skin and soft-tissue infections in recent years. In 2009, it was responsible for around 75% of community-acquired MRSA infections in northern Manhattan.

Anne-Catrin Uhlemann, a microbiologist at Columbia University Medical Center in New York, and her colleagues sequenced the genomes of 400 samples of MRSA collected from 161 people between 2009 and 2011, and compared them with samples from healthy people (many healthy people carry S. aureus bacteria, which could be MRSA). They also gathered data on study participants’ medical histories, antibiotic use and home locations to identify a network of USA300 transmission.

“This is an elegant and productive use of whole-genome sequencing in an epidemiological investigation,” says microbiologist Alexander Tomasz of the Rockefeller University in New York.

Evolving infection
Uhlemann and her team estimated the similarity between MRSA samples by checking how many different single-nucleotide polymorphisms (SNPs) — single-letter changes in their genomes — they had, and working out how fast these changes accumulated. The researchers calculated that the USA300 strains diverged from their most recent common ancestor around 1993. Although 85% of the samples were closely related to two known reference USA300 genomes, others were more diverse.

The team found that some of the samples originated in California and Texas, suggesting that USA300 was introduced into New York multiple times, rather than having one local ancestor.

Samples from people in a single household tended to be more similar to each other than to samples from other households, which implies that individuals within a home frequently exchange S. aureus. But people were also getting infected outside the home: “There were some households where we found multiple kinds of USA300, which is quite surprising,” says Uhlemann. “It suggests some kind of outside reservoir, such as a link to a hospital or a gym.”It seems that the USA300 strain spread in public spaces first, but it is now prevalent in households as well as hospitals. Further studies are needed to evaluate how hospitals might be involved in spreading the bacteria back into the community, say the study authors.

Uhlemann and her colleagues also found that nearly two-thirds of their bacterial samples were either fully or partially resistant to fluoroquinolone antibiotics, which are often prescribed for routine bacterial infections. The drug gets excreted onto skin surfaces, which the authors suggest may have contributed to the resistance in USA300: the bacteria get exposed to low levels of the antibiotic and can evolve ways to survive it. “We have to limit our antibiotic use because the consequences may really be a lot of collateral damage,” says Uhlemann.

Image: MRSA bacteria (pink) of various types were found in New York households. Credit: NIAID

This article is reproduced with permission from the magazine Nature. The
article was first published on April 21, 2014.

Reblogged from earthstory  162 notes
earthstory:



Fossil bees!This pair of images shows, on top, a modern-day leafcutter bee from the species Megachile rotundata and a very cool fossil find from the LaBrea Tar Pits.The bees come from a pair of full nests exhumed from a part of the tar pits; the same location has produced bones from animals 23,000 to 40,000 years old, and carbon-14 dating of the material in the nests gives the same age, so these bees are about that old. Many interesting specimens are preserved in the nests and have been found by scientists exhuming material from the tar pits, including the leafy walls of the nests themselves, adults, and pupae like this one.The bees are from species that are widespread in the United States, but the presence of these bees at this site actually helps constrain how their distributions have changed during the big climate shifts that happened since the nests were made. The bees today have expanded ranges at higher elevations than is suggested by these fossil finds, indicating that as the climate of the area warmed, the bees moved uphill to follow similar temperature levels.-JBBLozImage credit:Image credit: PLOS One (Open access journal):http://www.plosone.org/article/info%3Adoi/10.1371/journal.pone.0094724

earthstory:

Fossil bees!

This pair of images shows, on top, a modern-day leafcutter bee from the species Megachile rotundata and a very cool fossil find from the LaBrea Tar Pits.

The bees come from a pair of full nests exhumed from a part of the tar pits; the same location has produced bones from animals 23,000 to 40,000 years old, and carbon-14 dating of the material in the nests gives the same age, so these bees are about that old. Many interesting specimens are preserved in the nests and have been found by scientists exhuming material from the tar pits, including the leafy walls of the nests themselves, adults, and pupae like this one.

The bees are from species that are widespread in the United States, but the presence of these bees at this site actually helps constrain how their distributions have changed during the big climate shifts that happened since the nests were made. The bees today have expanded ranges at higher elevations than is suggested by these fossil finds, indicating that as the climate of the area warmed, the bees moved uphill to follow similar temperature levels.

-JBB

Loz

Image credit:

Image credit: PLOS One (Open access journal):
http://www.plosone.org/article/info%3Adoi/10.1371/journal.pone.0094724

txchnologist:

Viral Membrane Protects Medical Nanorobots From Immune System

Scientists say they have developed a cloaking device to spirit medical nanorobots of the future past immune systems into diseased cells. Their innovation comes from stealing a powerful weapon viruses wield to infect their hosts.

Some viruses wrap themselves in a protective membrane to avoid detection by their host’s immune system and enter cells they are trying to infect. A team at Harvard’s Wyss Institute for Biologically Inspired Engineering have been able to construct their own version of a viral membrane.

Read More

FRUIT FLY STUDY FINDS LONG-TERM IMPACT OF SLEEP DEPRIVATION 

Most of us know more about sleeping babies than snoozin’ fruitflies, but most young animals need buckets of sleep. Today, a study published in Science offers a comprehensive picture of why newborns sleep so much, and what difference it makes — at least to a fruit fly.

The goal “was to show that sleep early in development is required for normal structural growth of the brain,” says first author Matthew Kayser, a physician in the department of psychiatry at the University of Pennsylvania.

The basic plan was to reduce sleep among fruit flies that had just emerged from the pupal stage, and then look at their brains and behavior eight or nine days later. 

Research in the fruit fly showed:

Youngsters slept almost 17 hours a day, versus about 12 for oldsters. Sleep was also “deeper”: only about 25 percent of the young awoke after 10 seconds of light, versus 65 percent of oldsters.

Those drowsy, young flies also had 30 percent less dopamine than the older flies.

Normal low-dopamine condition in the young flies was due to decreased dopamine production among specific neurons that connect to a sleep-promoting structure.

A structure in the brain’s olfactory (smell) system was stunted in the sleep-deprived oldsters. (the structure in question detects pheromones — chemicals that flies use to communicate about mating and other necessities.)

Sehgal and Kayser already knew that young flies that got less sleep caused a significant reduction in courting and mating behavior. And the same result appeared in their dopamine-rich, sleep-deprived flies.

Image 1:Green indicates activity of dopamine neurons in the sleep-promoting dorsal fan-shaped body (outlined). Because dopamine inhibits the fan-shaped body, older flies (with high dopamine) sleep less than younger flies. Credit: Matthew Kayser

SOURCE

DEADLY EMOTICONS

Living connective tissue cells called fibroblasts taken from an embryonic mouse glow under the microscope to indicate that the CALM-AF-10 gene is active within them. Duke pediatric cancer researcher Daniel Wechsler’s team has identified the gene as part of a signaling sequence that can make cells immortal and lead to aggressive forms of leukemia. The discovery, which was featured on the cover of the journal Blood in June, points to a possible new therapeutic attack on leukemia.
 
Source: 1,110 WORDS

DEADLY EMOTICONS

Living connective tissue cells called fibroblasts taken from an embryonic mouse glow under the microscope to indicate that the CALM-AF-10 gene is active within them. Duke pediatric cancer researcher Daniel Wechsler’s team has identified the gene as part of a signaling sequence that can make cells immortal and lead to aggressive forms of leukemia. The discovery, which was featured on the cover of the journal Blood in June, points to a possible new therapeutic attack on leukemia.

 

Source: 1,110 WORDS

Reblogged from neurosciencestuff  130 notes
neurosciencestuff:

Common links between neurodegenerative diseases identified
Diseases of the central nervous system are a big burden to society. According to estimates, they cost €800 billion per year in Europe. And for most of them, there is no definitive cure. This is true, for example, for Parkinson disease. Although good treatments exist to manage its symptoms, they become more and more ineffective as the disease progresses. Now, the EU-funded REPLACES project, completed in 2013, which associated scientists with clinicians, has shed light on the abnormal working of a particular brain circuitry related to Parkinson’s disease. The results of the project suggest that these same circuits are implicated in different forms of pathologies. And this gives important insights into the possible common links between neurodegenerative diseases such as Parkinson and intellective disabilities or autism.
Existing treatments for Parkinson are very effective at the beginning. When the disease progresses, however, drugs, such as levodopa and so-called dopamine agonists, produce side effects that are sometimes even worse than the initial symptoms of the condition. In particular, they cause a complication called dyskinesia, characterised by abnormal involuntary movements. Therapies are therefore sought that allow better management of symptoms.
The project focused on the study of a highly plastic brain circuitry, which connects regions of the cerebral cortex with the basal ganglia. It is involved in very important functions such as learning and memory. “This system, based onglutamate as a mean of signalling between neurons, has also been discovered to be damaged in Parkinson disease,” says Monica Di Luca, professor of neuropharmacology at the University of Milan, Italy, and the project coordinator. She adds: “Parkinson’s more well-known and characteristic trait is the selective loss of cells producers of neurotransmitter dopamine.”
Researchers involved into the project studied the function and plasticity of this circuit in different animal models of Parkinson disease, from mice to non-human primates. They found that exactly the same alterations were present and conserved. This makes it an interesting and alternative target for trying to re-establish the correct functioning and reverse the symptoms of the disease.
One expert agrees with the need to target alternative target systems. “What researchers are trying to do is to intervene to modulate other systems that do not involve dopamine and obtain a better symptoms management,” explains Erwan Bezard, a researcher at the Neurodenerative Diseases Institute at the University of Bordeaux, in France. He also works on alternative targets in Parkinson disease. In monkeys, compounds that target glutamate receptors, used in combination with traditional drugs, have previously shown to improve some deficits in voluntary motor control.
But the research has also shed some light into apparently unrelated diseases. It is becoming more and more obvious that the same alterations in the working of the communication systems among neurons are shared among different diseases. “This is why we speak about ‘synaptopathies’: there are common players among Parkinson disease, autism and other forms of intellectual disabilities and even schizophrenia. Several of the mutated genes are the same, and affect the signalling systems through common molecules,” says Claudia Bagni, who works on synaptic plasticity in the context of intellectual disabilities at the University of Leuven, in Belgium and University of Rome Tor Vergata, in Italy. “For example, the glutamatergic system is also affected in the X-fragile syndrome, the most common form of inherited intellectual disability.”
Progress is in sight thanks to a much better understanding of the working of the abnormal synapses in Parkinson disease, and experiments performed in monkeys showing encouraging results. Indeed, “the team studied human primates, the model system closest to humans, and therefore their findings are relevant to human health.” says Bagni. Project researchers hope the door is now opened for the first clinical trials in humans. “We have identified a potential new target for treatment, and tested a couple of molecules in animals,” says Di Luca, the “next step would be to find a partnership with pharmaceutical industries interested in pursuing this research.”

neurosciencestuff:

Common links between neurodegenerative diseases identified

Diseases of the central nervous system are a big burden to society. According to estimates, they cost €800 billion per year in Europe. And for most of them, there is no definitive cure. This is true, for example, for Parkinson disease. Although good treatments exist to manage its symptoms, they become more and more ineffective as the disease progresses. Now, the EU-funded REPLACES project, completed in 2013, which associated scientists with clinicians, has shed light on the abnormal working of a particular brain circuitry related to Parkinson’s disease. The results of the project suggest that these same circuits are implicated in different forms of pathologies. And this gives important insights into the possible common links between neurodegenerative diseases such as Parkinson and intellective disabilities or autism.

Existing treatments for Parkinson are very effective at the beginning. When the disease progresses, however, drugs, such as levodopa and so-called dopamine agonists, produce side effects that are sometimes even worse than the initial symptoms of the condition. In particular, they cause a complication called dyskinesia, characterised by abnormal involuntary movements. Therapies are therefore sought that allow better management of symptoms.

The project focused on the study of a highly plastic brain circuitry, which connects regions of the cerebral cortex with the basal ganglia. It is involved in very important functions such as learning and memory. “This system, based onglutamate as a mean of signalling between neurons, has also been discovered to be damaged in Parkinson disease,” says Monica Di Luca, professor of neuropharmacology at the University of Milan, Italy, and the project coordinator. She adds: “Parkinson’s more well-known and characteristic trait is the selective loss of cells producers of neurotransmitter dopamine.”

Researchers involved into the project studied the function and plasticity of this circuit in different animal models of Parkinson disease, from mice to non-human primates. They found that exactly the same alterations were present and conserved. This makes it an interesting and alternative target for trying to re-establish the correct functioning and reverse the symptoms of the disease.

One expert agrees with the need to target alternative target systems. “What researchers are trying to do is to intervene to modulate other systems that do not involve dopamine and obtain a better symptoms management,” explains Erwan Bezard, a researcher at the Neurodenerative Diseases Institute at the University of Bordeaux, in France. He also works on alternative targets in Parkinson disease. In monkeys, compounds that target glutamate receptors, used in combination with traditional drugs, have previously shown to improve some deficits in voluntary motor control.

But the research has also shed some light into apparently unrelated diseases. It is becoming more and more obvious that the same alterations in the working of the communication systems among neurons are shared among different diseases. “This is why we speak about ‘synaptopathies’: there are common players among Parkinson disease, autism and other forms of intellectual disabilities and even schizophrenia. Several of the mutated genes are the same, and affect the signalling systems through common molecules,” says Claudia Bagni, who works on synaptic plasticity in the context of intellectual disabilities at the University of Leuven, in Belgium and University of Rome Tor Vergata, in Italy. “For example, the glutamatergic system is also affected in the X-fragile syndrome, the most common form of inherited intellectual disability.”

Progress is in sight thanks to a much better understanding of the working of the abnormal synapses in Parkinson disease, and experiments performed in monkeys showing encouraging results. Indeed, “the team studied human primates, the model system closest to humans, and therefore their findings are relevant to human health.” says Bagni. Project researchers hope the door is now opened for the first clinical trials in humans. “We have identified a potential new target for treatment, and tested a couple of molecules in animals,” says Di Luca, the “next step would be to find a partnership with pharmaceutical industries interested in pursuing this research.”

Reblogged from biovisual  594 notes

biovisual:

Baby Squid Photography by Jeannot Kuenzel - Malta
All rights reserved by Jeannot Kuenzel
sharing enabled / downloading enabled
Posted on Flickr March 29 and 31, 2014

top image
EGGS of Loligo vulgaris: the European squid, a large squid belonging to the family Loliginidae.

bottom image

Two stages of the development of a [European squid] are visible in the picture. These eggs are about 3mm in diameter; when the little squid inside has used up all the nutrients (all the yolk that is attached to it), it plops its suckers to the inside of the diaphragm and releases enzymes that will aid opening the shell, pushing through the opening - and a tiny new ALIEN of the DEEP is born :]

Notice the CHROMATOPHORES already embedded in its skin and the tiny little SIPHON… BTW, the SQUID on the left is actually laying on its back…