Posts tagged animals
Articles and news from the latest research reports.
Did bacteria spark evolution of multicellular life?
Bacteria have a bad rap as agents of disease, but scientists are increasingly discovering their many benefits, such as maintaining a healthy gut.
A new study now suggests that bacteria may also have helped kick off one of the key events in evolution: the leap from one-celled organisms to many-celled organisms, a development that eventually led to all animals, including humans.
Published this month in the inaugural edition of the new online journal eLife, the study by University of California, Berkeley, and Harvard Medical School scientists involves choanoflagellates (aka “choanos”), the closest living relatives of animals. These microscopic, one-celled organisms sport a long tail or flagellum, tentacles for grabbing food and are members of the ocean’s plankton community. As our closest living relative, choanos offer critical insights into the biology of their last common ancestor with animals, a unicellular or colonial organism that lived and died over 650 million years ago.
“Choanoflagellates evolved not long before the origin of animals and may help reveal how animals first evolved,” said senior author Nicole King, UC Berkeley associate professor of molecular and cell biology.
New studies reveal connections between animals’ microbial communities and behavior
New research is revealing surprising connections between animal microbiomes—the communities of microbes that live inside animals’ bodies—and animal behavior, according to a paper by University of Georgia ecologist Vanessa O. Ezenwa and her colleagues. The article, just published in the Perspectives section of the journal Science, reviews recent developments in this emerging research area and offers questions for future investigation.
The paper grew out of a National Science Foundation-sponsored workshop on new ways to approach the study of animal behavior. Ezenwa, an associate professor in the UGA Odum School of Ecology and College of Veterinary Medicine department of infectious diseases, and her coauthors were interested in the relationship between animal behavior and beneficial microbes.
Most research on the interactions between microbes and their animal hosts has focused on pathogens, Ezenwa said. Less is known about beneficial microbes or animal microbiomes, but several recent studies have begun to explore these connections.
"We know that animal behavior plays a critical role in establishing microbiomes," she said. "Once they’re established, the microbiomes then influence animal behavior in lots of ways that have far-reaching consequences. That’s what we were trying to highlight in this article."
(Image credit: sankax)
Memory: Do animals ever forget?
From pigeons that can recognise faces to a chimp that stores rocks to throw at visitors, all animals have memories. But how similar are they to ours?
(Image: Matt Jacob/Tendance Floue)
EVERY morning, you take a walk in the park, bringing some bread to feed the pigeons. As the days wear on, you begin to see the birds as individuals; you even start to name them. But what do the pigeons remember of you? Do they think kindly of you as they drop off to sleep at night, or is your face a blank, indistinguishable from the others strolling through the park?
These questions may seem whimsical, but knowing what other creatures recall is crucial if we are to understand their inner lives. It turns out that the range of mnemonic feats in the wild is nearly as varied as life itself.
If you take memory to mean any ability to store and respond to past events, even the simplest organisms meet the grade. Blobs of slime mould, for instance, which can slowly crawl across a surface, seem to note the timing of changes to their climate, slowing their movement in anticipation of an expected dry spell - even when it never actually arrives.
With the emergence of the first neurons about half a billion years ago, memories became more intricate as information could be stored in the patterns of electrical connections within the nervous system. This type of learning may have been behind the Cambrian explosion - the sudden appearance and rapid evolution of more complex species about 530 million years ago - because it enabled animals to exploit new niches, say Eva Jablonka at Tel Aviv University and Simona Ginsburg at the Open University of Israel.
Over the following few hundred million years, increasingly advanced skills could emerge with different forces driving the evolution of each creature’s mind. The result is a surprising range of mnemonic feats throughout the animal kingdom. Migratory cardinal fish, for instance, can remember where they laid their eggs during the breeding season and, after over-wintering in deep water, return to within half a metre of the same spot. Animals as diverse as lizards, bees and octopuses can learn the way out of a maze, and pigeons have an excellent visual recognition, learning to recognise more than a thousand different images. They can even recognise individual humans and aren’t fooled by a change of clothes.
Such skills, although impressive, don’t match our experiences of episodic memory, in which we immerse ourselves in specific events. A pigeon might learn to associate your face with food, but it probably can’t remember your last meeting in the way you might be able to recall details of your last trip to the park.
Japanese Study Shows Cute Pics Of Puppies May Improve Concentration
Has your boss ever caught you looking at pictures of adorable kittens on the internet when you’re supposed to be working? If so, Japanese researchers may have provided you with the perfect excuse for putting off work and gawking at those cute little critters.
A new study by psychologists at Hiroshima University indicates that viewing pictures of kittens or puppies actually improved the ability of test subjects to concentrate and focus.
Previous research by American psychologists showed that seeing cute animal pictures could improve fine motor skills when playing a game like the classic Milton Bradley board game Operation. This new study, published in the latest edition of PLOS ONE, expands on those findings by demonstrating that the improved focus applies to mental tasks as well as physical ones.
Night Monkey
A new species of night monkey is one of eight new mammals found during an expedition to northern Peru’s Tabaconas Namballe National Sanctuary (map), scientists announced recently.
A team of Mexican and Peruvian biologists found this “new heaven of unknown biodiversity” during a 2009-2011 expedition, according to a press statement.
Rarely seen and little-studied, night monkeys are listed as vulnerable by the International Union for Conservation of Nature (IUCN) and endangered by the Peruvian government, making the new discovery especially notable.
The as yet unnamed new species was found close to the border of Ecuador, said expedition co-leader Gerardo Ceballos, of the National Autonomous University of Mexico. Compared with two other species of night monkey in the region, the new one has a more uniform color and smaller skull.
(Source: National Geographic)
Tomoko Sakai and colleagues from Kyoto University in Japan subjected a pregnant chimp to a 3D ultrasound to gather images of the fetus between 14 and 34 weeks of development. The volume of its growing brain was then compared to that of an unborn human.
The team found that brain size increases in both chimps and humans until about 22 weeks, but after then only the growth of human brains continues to accelerate. This suggests that as the brain of modern humans rapidly evolved, differences between the two species emerged before birth as well as afterwards.
The researchers now plan to examine how different parts of the brain develop in the womb, particularly the forebrain, which is responsible for decision-making, self-awareness and creativity.
(Source: newscientist.com)
Naked mole-rats evolved to thrive in an acidic environment that other mammals, including humans, would find intolerable. Researchers at the University of Illinois at Chicago report new findings as to how these rodents adapted, which may offer clues to relieving pain in other animals and humans.
Duchess the elephant has UK’s first cataract op
Zookeepers are carefully monitoring an elephant who was the first in the UK to undergo an eye operation, to discover how much of her sight has returned.
Duchess was said to be recovering well after yesterday’s operation to remove a cataract from her left eye.
Paignton Zoo’s 42-year-old African elephant had her right eye removed in 2011 because of glaucoma, and has lately become practically blind.
Neil Bemment, curator of mammals and director of operations at the zoo, said staff had high hopes for the operation’s success. “It couldn’t have gone better,” he said. “She went down very smoothly under the anaesthetic and the operation went as well as we could hope.”
Mr Bemment said Duchess was still “disorientated” from the procedure and was being kept out of view with plenty of reassurance from staff.
"Her sight had deteriorated to the point where she could only tell the difference between light and shade," Mr Bemment said. "We’re hoping that his will restore her sight for most distances. She won’t be able to read about herself in the newspaper, but we’re hopeful that she will be more familiar in her surroundings."
(Source: thisisdevon.co.uk)
Light on the Brain
By Sabrina Richards | September 20, 2012
Researchers find that photoreceptors expressed in zebrafish hypothalamus contribute to light-dependent behavior.
Juvenile zebrafish.
Zebrafish larvae without eyes or pineal glands can still respond to light using photopigments located deep within their brains. Published in Current Biology, the findings are the first to link opsins, photoreceptors located in the hypothalamus and other brain areas, to increased swimming in response to darkness, a behavior researchers hypothesize may help the fish move toward better-lit environments.
“[It’s a] strong demonstration that opsin-dependent photoreceptors in deep brain areas affect behaviors,” said Samer Hattar, who studies light reception in mammals at Johns Hopkins University but did not participate in the research.
Photoreceptors in eyes enable vision, and photoreceptors in the pineal gland, a small endocrine gland located in the center of the vertebrate brain, regulate circadian rhythms. But photoreceptors are also found in other brain areas of both invertebrates and vertebrate lineages. The function of these extraocular photoreceptors has been best studied in birds, where they regulate seasonal reproduction, explained Harold Burgess, a behavioral neurogeneticist at the Eunice Kennedy Shriver National Institute for Child Health and Human Development.
Many opsins have been reported in the brains of tiny and transparent larval zebrafish, raising the possibility that light could be stimulating the photoreceptors even deep in the brain. To test for behaviors that may be regulated by deep brain photoreceptors, Burgess and his colleagues in Wolfgang Driever’s lab at the University of Freiburg removed the eyes of zebrafish larvae, and compared their behavior to larvae that retained their eyes. Although most light-dependent behavior required eyes, the eyeless larvae did respond when the lights were turned off, increasing their activity for a several minutes, though to a somewhat lesser extent than control larvae. But the fact that they responded at all suggests that non-retinal photoreceptors contributed to the behavior.
To confirm the role of the deep brain photoreceptors, the researchers also tested eyeless larvae that had been genetically modified to block expression of photoreceptors in the pineal gland. This fish still showed this jump in activity for several minutes after entering darkness.
Two different types of opsins—melanopsin and multiple tissue opsin—are expressed in the same type of neuron in zebrafish hypothalamus. Burgess and his colleagues looked at zebrafish missing the transcription factor Orthopedia, which is unique to these neurons, and found that the darkness-induced activity boost is nearly absent in these fish. To further narrow the search for the responsible photoreceptors, the researchers overexpressed melanopsin in hypothalamus neurons that co-express Orthopedia and melanopsin, and found that it increased the sensitivity of eyeless zebrafish to reductions in light. The results point to both melanopsin and Orthopedia as key players in modulating this behavior and pinpoint the location to neurons that coexpress these factors in the zebrafish hypothalamus.
Interestingly, the hypothalamus is one of the oldest parts of the vertebrate brain, said Detlev Arendt, a developmental biologist at the European Molecular Biology Laboratory in Heidelberg. “It’s very possible that this is one of the oldest functions”—one that evolved in “non-visual organisms” that had no eyes but still needed to sense light.
Although not as directed and efficient as eye-dependent behaviors that help fish swim toward light, Burgess speculates that deep brain opsins can still benefit zebrafish larvae. “You could imagine situation where it can’t see light, if a leaf falls on it and it doesn’t know where to swim. I think this behavior puts it in a hyperactive state where it swims wildly for several minutes until it reaches enough light for eyes to take over,” he explained, noting that such behavior is common in invertebrates.
It remains to be seen whether these deep brain opsins regulate other behaviors, perhaps in similar fashion to seasonal hormonal regulation in birds, but Hattar believes it is likely. “It’s beyond reasonable doubt there are many functions for these deep brain photoreceptors.”
(Source: the-scientist.com)
'Maternal gene' identified in mice
Researchers from The Rockefeller University in New York found that mice engineered to suppress the gene spent less time licking, nursing and retrieving their pups compared with a control group.
The findings, published in the Proceedings of the National Academy of Sciences, suggest the single gene could be responsible for motivating mothers to protect, feed and raise their young, the scientists said.
Previous studies have found that a brain region called the medial preoptic area controls aggression, sexual receptivity and maternal care in mice. In the new study, scientists artificially lowered the levels of the chemical in the medial preoptic area of female mice, to examine how they functioned without it.
They found that the mice spent less time caring for their pups but that their levels of aggression remained unchanged. Dr Ana Ribiero, who led the study, said: “The main finding of this paper is manipulation of a specific gene in a specific group of neurons (nerve cells) can drastically alter the expression of a complete, biologically crucial behaviour.” The effects were “remarkably specific” to maternal care because even related behaviours, such as aggression, remained unchanged, she added.