It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Thursday, July 20, 2023
POPULAR AQUARIUM FISH
Animal behavior: Neon tetra fish form queues to avoid bottlenecks
Schools of neon tetra fish (Paracheirodon innesi) use queuing to evacuate through narrow spaces without clogging or colliding, according to a study published in Scientific Reports.
Aurélie Dupont and colleagues observed neon tetra evacuate in groups of 30 through a narrow opening in a tank, which ranged in diameter from 1.5 to 4 centimetres, in response to the movements of a fishing net. Neon tetra measure approximately 0.5 centimetres wide and 3 centimetres long.
The authors observed that fish evacuated at faster rates through larger openings than smaller openings, but that fish evacuating through all sizes of opening tended to do so at a constant rate — with the exception of the last few fish in each group, who tended to exit more slowly. Although fish gathered around openings of all sizes prior to passing through them, the authors did not observe physical contact between evacuating fish. Together, the findings indicate that neon tetra may wait or queue before evacuating through narrow openings in order to maintain a preferred social distance and avoid clogging. This is similar to evacuation behaviours observed in previous studies of ants but is in contrast to those observed in herds of sheep and human crowds, where clogging often occurs.
The authors suggest that the behaviours of fish in their study may reflect the behaviours of schools of wild neon tetra passing between rocks in rivers. They propose that their findings could be used to inform the development of swarm robots, as well as traffic management methods for autonomous cars and human crowds.
ITHACA, N.Y. -- Plant geneticists have identified a mutation in a gene that causes the “weeping” architecture – branches growing downwards – in apple trees, a finding that could improve orchard fruit production.
For more than a century, growers have tied down apple branches when trees are young, in order to improve crop productivity. More research is needed to understand the mechanism for why branch bending improves yields, but studies have shown that the practice helps apple trees allocate more resources such as carbon and other nutrients toward reproductive growth (flowering and fruiting) than toward vegetative growth (branches and leaves).
In rare cases, trees are known to naturally grow downwards.
The new study, published early release on July 3 in the journal Plant Physiology, identified a variation, or allele, of MdLAZY1A – a gene that largely controls weeping growth in apple.
“The findings presented in this paper could be used to make existing apple cultivars grow somewhat downwards and/or with more spreading branches, so they can be more productive, and it can save on labor costs of tying branches down,” said senior author Kenong Xu, associate professor in the School of Integrative Plant Science Horticulture Section at Cornell AgriTech in the College of Agriculture and Life Sciences.
The mutation is rare, occurring in less than 1% of trees.
Now that the mutation – a single nucleotide substitution to the MdLAZY1A gene – has been identified, plant geneticists might use CRISPR/Cas-9 gene editing technology to develop cultivars with weeping-like growth, Xu said.
“We confirmed it through multiple transgenic studies,” Xu said. “We put that allele in a standard royal gala apple cultivar and the tree grew downward.”
To identify the gene, the researchers used a “forward genetics” approach, where they looked at the observable traits in more than 1,000 offspring of weeping cultivars, and separated those that exhibited weeping vs. normal growth. They then used advanced genetic sequencing techniques to compare the two populations to locate the genetic determinant.
Laura Dougherty, Ph.D. ’19, a former postdoctoral researcher at Cornell and currently a research geneticist at the U.S. Department of Agriculture Agricultural Research Service, is the paper’s first author. Co-authors include Susan Brown, professor in the School of Integrative Plant Science (SIPS) Horticulture Section at Cornell AgriTech, and Miguel Piñeros, adjunct associate professor in SIPS’ Plant Biology Section.
The study was funded by the National Science Foundation Plant Genome Research Program.
The power of flowers: New Zealand researchers discover that dahlia flowers have antidiabetic properties by targeting the brain as a key regulator of blood sugar
IMAGE: THE EXTRACT INHIBITS THE IKKΒ/NF-ΚB PATHWAY AND HAS MARKED ANTI-INFLAMMATORY PROPERTIES.view more
CREDIT: DOMINIK PRETZ, PHILIP M HEYWARD, JEREMY KREBS, JOEL GRUCHOT, CHARLES BARTER, PAT SILCOCK, NERIDA DOWNES, MOHAMMED ZUBAIR RIZWAN, ALISA BOUCSEIN, JULIA BENDER, ELAINE J BURGESS, GEKE ALINE BOER, PRAMUK KEERTHISINGHE, NIGEL B PERRY, ALEXANDER TUPS
In a clinical trial, University of Otago, Dunedin, New Zealand researchers have discovered a dahlia extract that improves blood sugar regulation without reported side effects in humans. This is a ground-breaking discovery as it for the first time suggests that dysfunctional glucoregulation by the brain can be targeted therapeutically using potent plant molecules to treat type 2 diabetes.
Almost 170 years ago, Claude Bernard, the founder of modern medicine, discovered that the brain plays an important role in the regulation of blood sugar. However, due to the discovery of insulin in 1922, his ground-breaking discovery got almost forgotten until recently. It has been subsequently established that the brain contains a region called the hypothalamus that plays an essential role in the regulation of blood sugar. This region can be damaged through inflammatory processes that are brought about by excess consumption of a Western Style diet enriched in long-chain saturated fatty acids, for example, contained in lard, and this is regarded as a hallmark in the pathogenesis of metabolic diseases like type 2 diabetes. In 2015, Associate Professor Tups and colleagues discovered that butein, a specific plant molecule, could block these inflammatory processes that damage the hypothalamus, and butein potently improved blood sugar regulation in mice.
In the current study, published inLife Metabolism, the New Zealand researchers reported that flowers of the non-toxic dahlia plant are a cultivable source of butein. Intriguingly, in a mouse model of diet-induced metabolic disease, an extract from this plant improved blood sugar regulation. Furthermore, the researchers demonstrate that the effect of butein was enhanced by the presence of two additional plant molecules that were obtained from the flower in a specific extraction process. When the researchers used molecular tools that stopped insulin from working in the brain, the ability of the dahlia extract to improve blood sugar regulation was lost, suggesting that the extract improves the brain’s function required for blood sugar regulation. This was substantiated by the observation that the extract enhanced the function of insulin in the brain and the discovery that the extract acts as a neuro-anti-inflammatory (Figure 1).
Confirming this, a randomized controlled crossover clinical trial on participants with prediabetes or type 2 diabetes revealed that the dahlia extract improved blood sugar regulation without reported side effects in humans.
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Reference: Dominik Pretz et al. (2023) A dahlia flower extract has anti-diabetic properties by improving insulin function in the brain. Life Metabolism. https://doi.org/10.1093/lifemeta/load026.
About Higher Education Press
Founded in May 1954, Higher Education Press Limited Company (HEP), affiliated with the Ministry of Education, is one of the earliest institutions committed to educational publishing after the establishment of P. R. China in 1949. After striving for six decades, HEP has developed into a major comprehensive publisher, with products in various forms and at different levels. Both for import and export, HEP has been striving to fill in the gap of domestic and foreign markets and meet the demand of global customers by collaborating with more than 200 partners throughout the world and selling products and services in 32 languages globally. Now, HEP ranks among China’s top publishers in terms of copyright export volume and the world’s top 50 largest publishing enterprises in terms of comprehensive strength.
About Life Metabolism
Life Metabolism is a fully open access, peer-reviewed journal that publishes one volume per year online, providing a platform for the publication of works of high significance and broad interest in all areas of metabolism. Life Metabolism welcomes several different article types, including original article, review article, research highlight, letter, editorial, perspective, and so on. Once a paper is accepted, Life Metabolism can publish a precopyedited, preproofed version of the paper online within 48 hours of receiving a signed licence, and this will be replaced by a copyedited, proofed version of the paper as soon as it is ready. The Editors-in-Chief are professors Peng Li at Tsinghua University and John R Speakman at University of Aberdeen, UK. In the first three years, there will be no publication costs for publishing in Life Metabolism, and Open Access fees will be waived.
Since 2020, the Heterogeneous Catalysis & Sustainable Chemistry group at the UvA’s Van ‘t Hoff Institute for Molecular Sciences has been working on using alkali metal borohydride salts as future hydrogen carriers. These solid salts can be stored safely in air under ambient conditions and release hydrogen gas only when reacting with water. However, controlling the hydrogen release, and thus preventing runaway reactions, is challenging. One solution is to stabilise the solution with a base, and control the hydrogen release by using a catalyst. The UvA team, led by Prof. Gadi Rothenberg, is developing such catalysts in collaboration with the Austrian Competence Centre for Tribology (AC2T) and the company Electriq Global.
Hydrogen destroys catalyst particles
Finding potential catalysts is easy, but getting them to work long enough to be commercially viable is not. The combination of high reaction pH and a continuous release of hydrogen bubbles destroys traditional catalysts within a few days. For instance, the team succeeded in designing highly active and selective cobalt-containing catalyst particles. The high activity, however, results in high volumes of hydrogen that rapidly destroy the particles.
The breakthrough came during a so-called Friday Afternoon experiment when MSc student Jeffrey Jonk and PhD student Fran Pope decided to try and encapsulate cobalt particles in chitosan spheres. Chitosan is a natural polymer that can be produced from chitin, the main component of insect exoskeletons and crustacean shells. It is a biodegradable, biocompatible material that is widely available on multi-ton scale, produced mostly from shrimp and crab shell waste.
The recurring amine groups on the chitosan backbone make it highly soluble in aqueous acidic solutions but sparingly soluble in basic ones. Chitosan spheres can therefore be relatively easy produced by dropping the liquid chitosan into a basic solution. A crucial property of the chitosan spheres is their flexibility which enables them to expand during the generation of hydrogen. They can thus “breathe out” the hydrogen bubbles without breaking. And since they are made at high pH, the basicity of the borohydride solution poses no problem.
Real-life potential for chitosan-based catalysts
The team tested the new catalysts in batch and continuous modes, monitoring the reactions by measuring the flow of hydrogen generated. A few mm-sized spheres loaded with 7% cobalt were sufficient to generate 40 mL hydrogen per minute in a continuous reactor for two days, showing the real-life potential of this new catalyst.
According to Rothenberg the work highlights the importance of catalyst stability as a research focus. “Many papers focus on activity and selectivity, because journals have become focused on publishing spectacular results”, he says. “Yet if you look at the chemical industry, none of these “spectacular” catalysts are used in practice. The reason is that running a successful reaction for a few hours, or even a few days, means nothing for large-scale processes. A real catalyst must work for months and years to be economically viable. We’re not there yet.”
Hydrogen may be energy carrier of the future, but it comes with its own set of challenges. When stored as a compressed gas or in liquid form, molecular hydrogen, H2, is highly energy intensive. This is an advantage in some applications, but a safety concern in others. For medium-scale storage and release on mobile installations, such as cranes, ships and generators, other modes of storing hydrogen are preferable. There are many forms of hydrogen carriers. High hydrogen storage capacity examples include ammonia, methanol, formic acid and others. Yet each has its pros and cons. Methanol has a high capacity (12.5 wt%) but dehydrogenation requires high temperatures and may also emit CO2. Ammonia may contaminate the H2 streams generated, and is a toxic gas itself under ambient conditions. As an alternative, alkali borohydrides can provide a safe source ofhydrogen, binding it chemically as a solid salt. A reaction with water releases the hydrogen, and the resulting metaborate salt by-product can be reprocessed and repurposed for hydrogen storage.
Original open-access paper:
From shrimp balls to hydrogen bubbles: Borohydride hydrolysis catalysed by flexible cobalt chitosan spheres. F. Pope, J. Jonk, M. Fowler, P.C.M. Laan, N.J. Geels, L. Drangai, V. Gitis and G. Rothenberg, Green Chem., 2023, 25, 5727-5734.DOI: 10.1039/d3gc00821e
VIDEO: APPROXIMATELY 99.9% OF FISH AND SHARK SPECIES ARE “COLD-BLOODED”, MEANING THEIR BODY TISSUES GENERALLY MATCH THE TEMPERATURE OF THE WATER THEY SWIM IN – BUT RESEARCHERS HAVE JUST DISCOVERED THE MIGHTY BASKING SHARK IS A ONE-IN-A-THOUSAND EXCEPTION.view more
CREDIT: TRINITY COLLEGE DUBLIN
Approximately 99.9% of fish and shark species are “cold-blooded”, meaning their body tissues generally match the temperature of the water they swim in – but researchers have just discovered the mighty basking shark is a one-in-a-thousand exception. Instead, these sharks keep the core regions of their bodies warmer than the water like the most athletic swimmers in the sea such as great white sharks, mako sharks and tuna.
The latter examples are so-called “regional endotherms” and are all fast swimming, apex predators at the top of the food chain. Scientists have long reasoned that their ability to keep warm helped with this athletic predatory lifestyle, and that evolution had shaped their physiology to match their requirements.
However, an international team of researchers led by those from Trinity College Dublin, has now shown that gentle, plankton-feeding basking sharks are also regional endotherms despite having very different lifestyles to white sharks and tunas.
This surprising discovery has implications for conservation, as well as raising a plethora of ecological and evolutionary questions.
Haley Dolton, PhD Candidate in Trinity’s School of Natural Sciences, was lead author of the study that has just been published in international journal, Endangered Species Research. She said:
“The basking shark is a shining example of how little we know about shark species in general. That we still have lots to uncover about the second biggest fish in the world – such a huge, charismatic animal that most people would recognise it – just highlights the challenge facing researchers to gather what they can about species to aid in effective conservation strategies.
Basking sharks gained legal protection in Irish waters just last year, with the species having undergone significant population declines throughout the NE Atlantic in the last century. But they still face many challenges in the future.
Haley Doltonadded: “Regional endotherms are thought to use more energy, and possibly respond differently to ocean warming than other fish species. So lots more work will need to be done to work out how these new findings regarding an endangered species might change previous assumptions about their metabolism or potential distribution shifts during our climate crisis, which is something marine biologists are focusing on as our planet and its seas continue to warm.
“Hopefully this kind of research will continue the momentum needed to effectively protect these incredible animals in Irish waters and further afield.”
To make the discovery, the research team (including scientists from University of Pretoria, Marine Biological Association, Queen’s University Belfast, Zoological Society of London, University of Southampton, and Manx Basking Shark Watch) first undertook dissections of dead basking sharks that washed up in Ireland and the UK.
They found that the sharks have cruise-swimming muscles located deep inside their bodies as seen in white sharks and tunas; in most fish this “red” muscle is instead found toward the outside of the animals.
They also discovered basking sharks have strong muscular hearts that probably help generate high blood pressures and flows. Most fish species have relatively “spongy” hearts, whereas basking shark hearts are more typical of the regional endotherm species.
Next, the team designed a new low-impact tagging method to record body temperature of free-swimming basking sharks off the coast of Co Cork, Ireland. Researchers were able get close enough to 8 m basking sharks to safely deploy the tags, which recorded muscle temperature just under the skin for up to 12 hours before they automatically detached from the animals and were collected by the researchers.
These tags revealed that basking shark muscles are consistently elevated above water temperatures, and to almost exactly the same extent as their regionally-endothermic predatory cousins.
Nicholas Payne, Assistant Professor in Trinity’s School of Natural Sciences, was senior author of the study. He said:
“These results cast an interesting new light on our perception of form versus function in fishes because until now we thought regional endothermy was only found in apex predatory species living at high positions in the marine food web.
“Now we have found a species that grazes on tiny plankton but also shares those rather uncommon regional endotherm features, so we might have to adjust our assumptions about the advantages of such physiological innovations for these animals.
“It’s a bit like suddenly finding that cows have wings.”
IMAGE: AN ADULT MALE WITH DEEP TOOTH RAKE MARKSview more
CREDIT: DAVID ELLIFRIT / CENTER FOR WHALE RESEARC
Post-menopause female killer whales protect their sons – but not their daughters – from fights with other whales, new research shows.
Scientists studied “tooth rake marks” – the scarring left when one whale scrapes their teeth across the skin of another – and found males had fewer marks if their mother was present and had stopped breeding.
Only six species – humans and five species of toothed whales – are known to experience menopause, and scientists have long been puzzled about why this occurs.
The new study – by the universities of Exeter and York, and the Center for Whale Research – adds to growing evidence that post-menopause females boost the life chances of their offspring, especially males.
“These males had 35% fewer tooth marks than other males.
“For males whose mother was still breeding, we found no evidence that her presence reduced tooth rake injuries.
“We can’t say for sure why this changes after menopause, but one possibility is that ceasing breeding frees up time and energy for mothers to protect their sons.
“Tooth rake marks are indicators of physical social interactions in killer whales and are typically obtained through fighting or rough play.”
The study is part of long-term research on “southern resident” killer whales, which live off the Pacific coast of North America.
The body of evidence suggests that – instead of competing with their daughters to breed – female killer whales have evolved to pass on their genes by helping their children and grandchildren.
Commenting on why females focus efforts on their sons, Grimes said: “Males can breed with multiple females, so they have more potential to pass on their mother’s genes.
“Also, males breed with females outside their social group – so the burden of raising the calf falls on another pod.”
Southern resident killer whales feed on salmon and have no natural predators apart from humans, so tooth marks on their skin can only be inflicted by other killer whales.
This may happen within social groups, or when two pods meet.
Commenting on how mothers protect their sons, Professor Darren Croft, also from the University of Exeter, said: “We can’t say for sure.
“It’s possible that the older females use their experience to help their sons navigate social encounters with other whales.
“They will have previous experience of individuals in other pods and knowledge of their behaviour, and could therefore lead their sons away from potentially dangerous interactions.
“The mothers might also intervene when a fight looks likely.”
Professor Croft added: “The similarities with humans are intriguing.
“Just as in humans, it seems that older female whales play a vital role in their societies – using their knowledge and experience to provide benefits including finding food and resolving conflict.”
Professor Dan Franks, from the Department of Biology at the University of York, said: "Our findings offer captivating insights into the role of post-menopausal killer whale mothers.
“They perform protective behaviour, reducing the incidence of socially inflicted injuries on their sons.
“It's fascinating to see this post-menopausal mother-son relationship deepening our understanding of both the intricate social structures in killer whale societies and the evolution of menopause in species beyond humans."
The study was supported by the Natural Environment Research Council.
The paper, published in the journal Current Biology, is entitled: “Postreproductive female killer whales reduce socially inflicted injuries in their male offspring.”
An adult male with travelling with its post-reproductive mother
IMAGE: AN ADULT MALE ORCA WITH TOOTH RAKE MARKSview more
CREDIT: COPYRIGHT DAVID ELLIFRIT, CENTER FOR WHALE RESEARCH
Female killer whales live up to ninety years in the wild, and most live an average of twenty-two years after menopause. Scientists have long wondered why humans and some whale species spend a significant portion of their life not reproducing. Previous studies show that, even after having their last calf, killer whale mothers take care of their families by sharing the fish they catch. Now, in a study published on July 20 in the journal Current Biology, researchers note that these mothers can also provide social support to their sons by protecting them from being injured by other orcas.
“The motivation of this project was really to try and understand how these post-reproductive females are helping their offspring,” says first author Charli Grimes, an animal-behavior scientist at the University of Exeter. “Our results highlight a new pathway by which menopause is adaptive in killer whales.”
The research team studied southern resident orcas, a group of orcas that live off the Pacific Northwest coast. These killer whales live in matriarchal social units that consist of a mother, her offspring, and the offspring of her daughters. Although male orcas will outbreed with whales from other pods, both males and females stay in their unit of birth, with their mother, for life.
Using data from the Center for Whale Research’s annual photographic census of the orca population, the researchers looked for evidence of scarring on each catalogued whale’s skin. Killer whales have no natural predators other than humans, so a tooth mark that is able to puncture an orca’s skin was most likely inflicted by another orca.
The study found that, if a given male’s mother was still alive and no longer reproducing, that male would have fewer tooth marks than his motherless peers or his peers with a mother who was still reproducing.
“It was striking to see how directed the social support was,” says senior author Darren Croft (@DarrenPCroft), an animal-behavior scientist at the University of Exeter. “If you have a post-reproductive mother who’s not your mother within the social group, there’s no benefit. It’s not that these females are performing a general policing role. These post-reproductive mothers are targeting the support they are giving to their sons.”
The researchers still can’t say for certain what kinds of social conflicts are leading to tooth marks or how older females are protecting their sons against them. They do note that post-menopause females have the lowest incidence of tooth marks in the entire social unit, suggesting that they do not physically intervene in a conflict. If older orca females play a similar role to that of older women in human societies, they might be acting as mediators, preventing conflict from occurring in the first place. To explore this further, the researchers plan on completing an additional study by using drone footage to observe whale behavior from above.
“It’s possible that with age comes advanced social knowledge. Over time, they might have a better understanding of other social groups,” says Grimes. “Given these close mother-son associations, it could also be that she is present in a situation of conflict so she can signal to her sons to avoid the risky behavior they might be participating in.”
“We’ve got hypotheses, but we need to test them by seeing what’s happening under water when these different groups interact,” says Croft. “We’ve learned so much from this population, but we’ve still got so much to learn from them.”
This work was supported by the Natural Environment Research Council. The authors declare no conflicts of interest.
Current Biology (@CurrentBiology), published by Cell Press, is a bimonthly journal that features papers across all areas of biology. Current Biology strives to foster communication across fields of biology, both by publishing important findings of general interest and through highly accessible front matter for non-specialists. Visit:http://www.cell.com/current-biology. To receive Cell Press media alerts, contactpress@cell.com.
A post menopause female orca traveling with her adult son
