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)
Wednesday, June 22, 2022
Ovum‑in‑ovo egg suggests titanosaur's reproductive biology was more like birds than reptiles
Field photograph and microscopic images of the eggshell from egg number C showing oospecies Fusioolithus baghensis characterized by fan-shaped shell units with arching growth lines and basal end cap units. (a) The ovum-in-ovo egg with the boxed area showing the region from where the specimen was extracted. (b) Radial Scanning Electron Microscope (SEM) photomicrograph of the eggshell showing partially preserved fan-shaped shell unit. (c) Photomicrograph of the radial thin section of the eggshell under polarized light microscopy showing partially preserved shell units (see black arrow) and characteristic swollen basal cap units (see red arrow). (d) Photomicrograph of the radial thin section of the eggshell under polarized light microscopy exhibiting fused shell units and growth lines (see black arrow) and swollen basal cap (see red arrow). Credit: Scientific Reports (2022). DOI: 10.1038/s41598-022-13257-3
A trio of researchers, two with the University of Delhi and a third with the Dhar District, Higher Secondary School, has found the first-ever example of an ovum-in-ovo dinosaur egg. In their paper published in Scientific Reports, Harsha Dhiman, Guntupalli Prasad and Vishal Verma describe the dinosaur egg they found and why they believe it suggests at least one type of dinosaur reproduction was more like modern birds than reptiles.
The fossilized egg was found in the Dhar district, Madhya Pradesh, in a central western part of India and was in good enough condition to allow the researchers to see that it was ovum-in-ovo, or egg-in-egg. In birds, such eggs are created when one egg is pushed back into the body of the bird and into the reproductive system, where it becomes embedded in another egg still in the process of forming. Such egg formations are not seen in reptiles; thus, the find suggests that the reproductive system of the dinosaur that laid the egg, a titanosaur, was more similar to modern birds than to reptiles. Dating of the nesting site where the egg was found showed it be from approximately 66 to 100 million years ago.
The egg was found at a location called Nest p7 at the dig site where several other dinosaur fossils, including eggs, have been found—all titanosaurs. Fossils of such dinosaurs, which were a type of sauropod, are widespread, found on all modern continents. Prior evidence has also shown that the titanosaurs were thriving right up until the extinction event that wiped them out, along with all the other non-bird dinosaurs.
The researchers noted that the fossilized egg had two complete shells, one inside the other, separated by a small gap—a clear sign that it was ovum-in-ovo. The researchers were able to capture cross-sectional images of the egg and found it to be remarkably similar to ovum-in-ovo found in modern birds. They suggest that the dinosaur was part of a group that had evolved to lay eggs sequentially and that ovum-in-ovo is not exclusive to birds.Non-avian dinosaur found to have laid blue eggs
More information:Harsha Dhiman et al, First ovum-in-ovo pathological titanosaurid egg throws light on the reproductive biology of sauropod dinosaurs,Scientific Reports(2022).DOI: 10.1038/s41598-022-13257-3
The illustrated forminifer species Uvigerina peregrina was recovered from a sample from Peruvian oxygen minimum zone in 2017. Credit: Jan Michels
In the context of climate change, the phenomenon of oxygen-depleted areas in the ocean has become a focus of scientific attention in recent years. These areas, known as oxygen minimum zones (OMZ), are located in the Indian Ocean or off the Peruvian coast in the Pacific, for example. Depending on water depth, little or no oxygen is found there.
In a new study, a transdisciplinary research team with the participation of Kiel University and GEOMAR Helmholtz Centre for Ocean Research Kiel was able to gather previously unknown details about the origin and adaptation of certain unicellular organisms to these special environmental conditions and their influence on the marine nutrient cycle: Because their metabolism does not rely on oxygen, numerous species of foraminifera are found in the OMZ. These are unicellular, shell-forming microorganisms that already feature a cell nucleus and thus belong to the so-called eukaryotes.
Their special lifestyle is based on so-called anaerobic respiration or nitrate respiration, in which nitrate available in the water is converted into molecular nitrogen in the absence of oxygen. Nitrogen, as a basic nutrient of all living organisms, is no longer biologically available as a result of this process and is thus lost to the marine habitat. The research team led by Professor Tal Dagan of the Institute of General Microbiology at Kiel University has now been able to prove via genome analyses that the ability of nitrate respiration, still preserved in most foraminifera today, might have originated in a common predecessor around 100 million years ago.
Their analyses also showed that the foraminifera probably rely on bacterial support for a specific step in the process of nitrate respiration, also known as denitrification, and are therefore associated with certain symbiotic bacterial species. The Kiel researchers, who are active in the Kiel Evolution Center (KEC) and the Collaborative Research Center (CRC) 1182 Origin and Function of Metaorganisms, published their results together with international colleagues recently in the journal Proceedings of the National Academy of Sciences.
Dr Christian Woehle (left) and Dr Joachim Schönfeld handling a multicorer during a sampling expedition in Kristineberg, Sweden 2015. Credit: Jan Michels
Nitrate respiration originated millions of years ago
The research team examined sediment samples from the Peruvian OMZ and was able to identify around ten different species of foraminifera living in the seafloor. From previous research almost all of these species are known to be capable of nitrate respiration. The scientists therefore looked for genes that are likely involved in nitrate metabolism.
"Indeed, numerous of these genes were found in our samples from Peru. Since these species have been shown to perform nitrate respiration, we were thus able to provide a causal link between the presence of the genes and their function," says first author Dr. Christian Wöhle, a former member of Dagan's Genomic Microbiology group at Kiel University.
In a next step, the researchers traced back how long ago the evolutionary acquisition of nitrate respiration could have occurred. To do this, they created so-called phylogenetic trees, which visualize the relationships between different species to identify a possible common ancestor. "In this way, we were able to narrow down a time period for three specific groups of foraminifera. All earlier species lacked the genetic equipment for nitrate respiration," Wöhle explains. "Thus, we could reconstruct that they probably go back to a common predecessor that must have developed this trait in the Cretaceous period about 100 million years ago," Wöhle continues.
Some specimens of the studied species Uvigerina striata sieved out of the sediment using sieves of various sizes. Credit: Prof. Tal Dagan
Microbes provide missing metabolic step
In a metagenome analysis of the Peruvian sample material, the researchers also examined the genetic material of all species found to establish possible symbiotic relationships between various foraminifera and bacteria. First, comparisons with foraminifera species from distant locations showed that they are often associated with a similar and stable composition of bacterial species, regardless of geography.
"In our study, we further noticed an association between a particular genus of foraminifera and so-called Desulfobacteria. These bacteria have previously been observed to be colonizers of other groups of foraminifera," said Dr. Alexandra-Sophie Roy, a former member in the Genomic Microbiology group.
Another indication of a symbiotic relationship between these bacteria and the denitrifying foraminifera was found in the form of the so-called NapA gene. In Desulfobacteria, it is responsible for an enzyme that can initiate the start of the multistep process of nitrate respiration.
"Earlier studies showed that precisely this first step cannot be performed by foraminifera themselves. Therefore, it seems plausible that the bacteria take over this part of nitrate respiration, for example by converting nitrate into nitrite that is useful for their hosts, and therefore form a stable symbiosis with the foraminifera," Roy explains.
New insights into global nutrient cycles
"Our work on the origins and evolution of the genetic basis of ancient nitrate metabolism provides us with important new insights to better understand today's global biogeochemical cycles," says Professor Tal Dagan, KEC board member and project leader in the CRC 1182. In particular, she said, the possible involvement of bacteria in nitrate respiration in the oxygen-depleted ocean is an important but so far understudied component that needs further research in the future.
"The accelerating pace of global environmental change requires deepened knowledge of the turnover and distribution of elemental substances in the ocean. Our new results contribute to a better understanding of the impact of climate change on oxygen-dependent nutrient cycles in the ocean and their effects on marine organisms," adds Dr. Joachim Schönfeld from GEOMAR, who was also involved in the study.How nutrients are removed in oxygen-depleted regions of the ocean
More information: Christian Woehle et al, Denitrification in foraminifera has an ancient origin and is complemented by associated bacteria, Proceedings of the National Academy of Sciences (2022). DOI: 10.1073/pnas.2200198119
Mineralogical data across the extinction event. Mineralogical data from (A) Ubara and (B) Akkamori. Quartz (qtz); pyrite (pyr); berthierine (bth); Fe-illite; and frw_s. Credit: Nature Communications (2022). DOI: 10.1038/s41467-022-31128-3
The end-Permian mass extinction is the most severe mass extinction event ever recorded, during which ~80% of marine species went extinct
While the beginning of this extinction event was driven by an extreme and rapid warming event, recovery of both global climate and ecosystems was extremely sluggish. Temperatures remained lethally hot and ecosystems remained depleted for over 5 million years.
Based on our current understanding of how the carbon cycle and climate operates, temperatures ought to have recovered much more quickly.
This delayed recovery stands out from all other known mass extinction events, and has baffled scientists for many years without any real explanation.
A recently released paper published by Nature Communications, "Marine siliceous ecosystem decline led to sustained anomalous Early Triassic warmth," by University of Waikato researchers Terry Isson and Sofia Rauzi from the Earth-Life Interactions (ELI) research group, suggests that the decline of silica secreting marine organisms across this event both exacerbated climate change and was responsible for the 5 million year delay in global temperature recovery.
This provides for the first time, an comprehensive explanation for why it took so long for temperatures to recover to what they were before the mass extinction event.
Clay minerals form in the oceans and in the process release CO2. Clays minerals are fundamentally made up of silica and so cannot form without it. Silica secreting organisms compete for this silica, meaning that a healthy siliceous ecosystem that uses large amounts of silica will act to lower the amount of CO2 released from clay mineral formation.
It is well established that there was widespread loss of silica secreting organisms in the oceans during the end-Permian mass extinction event, and that these organisms did not recover for 5 million years. This research demonstrates, using a carbon cycle model and also mineralogical analysis, that this would have led to increased CO2 release into the atmosphere during this time, keeping temperatures on Earth high for a prolonged period of time.
This research provides the first ever direct evidence that silica secreting organisms play a very prominent role in regulating climate on Earth that has previously never been recognized.Rethinking planetary climate controls
More information: Terry T. Isson et al, Marine siliceous ecosystem decline led to sustained anomalous Early Triassic warmth, Nature Communications (2022). DOI: 10.1038/s41467-022-31128-3
Hackmanite turns purple under UV irradiation, and the color fades back to white in a few minutes under regular white light. This sample is from Greenland. Credit: Mika Lastusaari
While investigating hackmanite, researchers found that it can change color upon exposure to UV radiation repeatedly without wearing out. The results show that the inexpensive hackmanite, which is easy to synthesize, also has high durability and multiple applications.
A research group at the University of Turku, Finland, has been investigating and developing the properties of the hackmanite for almost a decade. Applications such as personal UV monitoring and X-ray imaging have been developed based on hackmanite's ability to change color.
Hackmanite changes its color from white to purple under UV irradiation and eventually reverts back to white if no UV is present. The structural features enabling such repeated changes have so far been unclear. Now, upon investigating three natural minerals—hackmanite, tugtupite and scapolite—the researchers have found the answer.
These color-changing minerals are inorganic natural materials, but there are also organic compounds, hydrocarbons, that can change color reversibly due to exposure to radiation. These hydrocarbons, however, can only change color a few times before their molecular structure breaks down. This is because the color change involves a drastic change in the structure, and undergoing this change repeatedly eventually breaks the molecule.
"In this research, we found out for the first time that there is actually a structural change involved in the color change process, as well. When the color changes, sodium atoms in the structure move relatively far away from their usual places and then return back. This can be called 'structural breathing,' and it does not destroy the structure even if it is repeated a large number of times," reports Professor Mika Lastusaari from the Department of Chemistry at the University of Turku, Finland.
White scapolite turns blue under UV irradiation. The coloration and reversion back to white after the removal of the UV source take only a few seconds, because atoms in the structure move short distances. Scapolite is a rather common mineral. This sample is from Afghanistan. Credit: Sami Vuori
Researchers proved that hackmanite's ability to alternate between white and purple forms is highly repeatable
According to Professor Lastusaari, the durability is due to the strong three-dimensional cage-like overall structure of these minerals, which is similar to that found in zeolites. In detergents, for example, the cage-like structure enables zeolite to remove magnesium and calcium from water by binding them tightly inside the pores of the cage.
These color-changing minerals, all processes associated with the color change occur inside the pores of the zeolitic cage where the sodium and chlorine atoms reside. That is, the cage-like structure allows atomic movement inside the cage while keeping the cage itself intact. This is why minerals can change color and revert back to their original color practically indefinitely," Doctoral Researcher Sami Vuori explains.
Previously, it has been known that scapolite changes color much faster than hackmanite, whereas tugtupite's changes are much slower.
"Based on the results of this work, we found out that the speed of the color change correlates with the distance that the sodium atoms move. These observations are important for future material development, because now we know what is required from the host structure to allow the control and tailoring of the color change properties," says Doctoral Researcher Hannah Byron.
"There were no characterization methods available for the research on color changing minerals, which is why we have developed new methods by ourselves. However, it is difficult to interpret the results unambiguously based on experimental data alone. In fact, we could not have reached the present conclusions without strong support from theoretical calculations, since only the combination of experimental and computational data shows the whole picture. We owe a great many thanks to our collaborator Professor Tangui Le Bahers and his group, who have developed and advanced suitable computational methods to such detail and accuracy that would not have been possible just a few years ago," says Lastusaari.
Tugtupite is a rare mineral, which turns pink when exposed to UV radiation. The return back to white takes several hours, because it requires large atomic movements. This sample is from Greenland. Credit: Sami Vuori
Hackmanite has amazing potential for applications
The Intelligent Materials Research Group at the Department of Chemistry of the University of Turku, led by Lastusaari, has long conducted pioneering research on materials with light and color-related properties, especially on hackmanite. They are currently exploring numerous applications for hackmanite, such as possibly replacing LEDs and other light bulbs with the natural mineral and using it in X-ray imaging.
One of the most interesting avenues that the researchers are currently exploring is a hackmanite-based dosimeter and passive detectors for the International Space Station, intended to be used to measure the radiation dose uptake of materials during space flights.
"The strength of hackmanite's color depends on how much UV radiation it is exposed to, which means that the material can be used, for example, to determine the UV index of Sun's radiation. The hackmanite that will be tested on the space station will be used in a similar fashion, but this property can also be used in everyday applications. We have for example already developed a mobile phone application for measuring UV radiation that can be used by anyone," explains Sami Vuori.
The paper was published in June in the PNAS journal.
More information:Pauline Colinet et al, The structural origin of the efficient photochromism in natural minerals,Proceedings of the National Academy of Sciences(2022).DOI: 10.1073/pnas.2202487119
A fishy capture reveals a prized species moving south
by Southern Cross University
Credit: Dr. Benjamin Mos
A fishing expedition on the NSW Mid North Coast has hooked an unexpected catch for a Southern Cross University marine researcher.
When brothers Benjamin and Daniel Mos went fishing over summer, the pair did not anticipate their catch to be anything other than a photo opportunity or dinner. Instead the fish they captured and released, commonly called the barred javelin, spurred them to write a scientific paper now published in Journal of Fish Biology.
According to Dr. Benjamin Mos, a marine biologist based at Southern Cross University's National Marine Science Center, it was rare to find the barred javelin in New South Wales waters.
"While this species is likely well-known to fishers in Queensland, it is not something we typically find here. We had to look through a few fish books and websites to identify our specimens," Dr. Mos said.
"Our captures in late 2021 and early 2022 are the southern-most records for the barred javelin reported to date. And there may be more around the area.
"At the end of May 2022, we saw posts on social media about a barred javelin caught from Deep Creek, which is just north of the Nambucca River where we found our specimens."
The species has been previously sighted in the Richmond River and Clarence River systems on the NSW North Coast, which are around 200 kilometers north of the Nambucca River where the latest specimens were discovered.
It is not known if the arrival of the barred javelin this far south into NSW is due to changing ocean conditions.
"It is possible the sightings this far south are a one-off event. However, our sightings fit with a broader pattern occurring in the waters off south-eastern Australia which points towards a role of climate change," said Dr. Mos.
"In our region dozens of tropical species are moving southwards where oceans and estuaries are also warming faster than the global average."
According to Atlas of Living Australia records, the barred javelin has not been collected in NSW in more than 50 years.
The barred javelin's southernmost stronghold is Queensland's Moreton Bay, off Brisbane, where the species supports economically important recreational and commercial fisheries.
The species is a popular sport fish and reportedly good eating. The barred javelin grows to around 80cm in length and is found in estuaries and offshore to around 75 meters deep.
Dr. Mos said the newcomer was not of particular environmental concern at present. The barred javelin's relative rarity in NSW and generalist diet means it is unlikely to outcompete local species.
In the Mediterranean, tropical fishes moving into sub-tropical or temperate areas pose threats to biodiversity, public health, and fisheries. Two examples include herbivorous rabbitfishes chomping away at kelp forests, and poisonous silver-cheeked toadfish fouling fishers' nets and stealing their catch.
In contrast, the barred javelin may be welcomed by NSW recreational and commercial fishers.
"It is important that we understand where this species is showing up, and in what numbers," Dr. Mos said.
"If greater numbers make their way to NSW over coming decades the barred javelin may become a more common catch. It might then be necessary to look at whether specific size or catch limits are needed to ensure more fishers have the opportunity to catch this fish."
Because the barred javelin has been rarely captured in northern NSW, there are at present no specific catch or size limits for this species in NSW. A maximum daily bag limit of 20 applies to all fish in NSW that do not have specific bag and size limits. A 40 cm minimum length and bag limit of 10 applies in Queensland waters.
More information:Benjamin Mos et al, Range expansion of a widespread Indo‐Pacific haemulid, the barred javelin Pomadasys kaakan (Cuvier, 1830), in a climate change hotspot,Journal of Fish Biology(2022).DOI: 10.1111/jfb.15125
Modern phoenix: The bird brought back from extinction in Japan
by Sara Hussein
Wild tokis have been brought back from local extinction on Japan's Sado island.
Every day for the past 14 years, 72-year-old Masaoki Tsuchiya has set out before sunrise to search for a bird rescued from extinction in Japan.
Starting his car under star-dotted skies unpolluted by light, he works alone in the pre-dawn chill, marking sightings or absences in a planner, interrupted only by the crackle of a walkie-talkie.
The bird he is looking for is called "toki" in Japanese, and its presence on his home of Sado island is testament to a remarkable conservation program.
In just under two decades, Japan's population of wild toki has gone from zero to nearly 500, all on Sado, where the bird's delicate pink plumage and distinctive curved beak now draw tourists.
It's a rare conservation success story when one in eight bird species globally are threatened with extinction, and involved international diplomacy and an agricultural revolution on a small island off Japan's west coast.
A cautionary tale
Tsuchiya, stocky and spry with an impish grin, doesn't eat breakfast until he has made all his stops, and after years of practice he can spot chicks hidden in nests through the monocular attached to his rolled-down car window.
He points to virtually imperceptible marks on a road or a wall that help him remember where to park and start surveying.
Timeline showing how efforts to save the Japanese crested ibis has unfolded.
"The number I see at this spot depends on the season," he explains.
Some days dozens of the birds appear in one area, something unimaginable in 2003, when a toki called Kin or "gold" died in a cage on Sado at the record-breaking age of 36.
Her death meant not a single wild-born toki was left in Japan, despite the bird being so synonymous with the country that it is also known as the Japanese crested ibis.
"I knew the day was coming. She was very old and frail," Tsuchiya said. "But it was still a real pity."
Efforts to get Kin to mate with Sado's last wild-born male toki Midori—meaning "green"—had long since failed, and she lived out her last years as a curiosity and a cautionary environmental tale.
Her death made national headlines and appeared to mark the end of a long and seemingly futile battle to protect the toki in Japan, where its feathers even inspire the word for peach pink: "toki-iro".
But now so many roam the skies and rice paddies of Sado that local officials have gone from discouraging eager birdwatchers to training guides to help visitors spot the local icon, and the government is even studying reintroducing the bird elsewhere.
Also known as the Asian crested ibis, Japan's last toki died in 2003.
Wiped out
Wild toki once lived across Japan, as well as in Russia, Taiwan and South Korea.
They were considered a pest that damaged rice plants, but during Japan's Edo era, from 1603 to 1867, hunting restrictions meant only high-ranking officials could actively pursue birds like toki.
That changed in the Meiji era and as guns became more available. Toki meat was believed to have health benefits, and its feathers were favored for everything from dusters to decorative flourishes on hats.
"Over just 40 years, the toki basically disappeared," said Tsuchiya on an observation deck where visitors now try to spot the bird.
By the early 1930s, only a few dozen toki remained in Japan, mostly on Sado and the nearby Noto peninsula, and the species won protected status.
A fresh threat then emerged during Japan's post-war drive for growth: rising use of chemical fertilizers and pesticides.
A small population of toki were found in China and a successful breeding programme allowed the birds to be reintroduced to Sado.
Toki feed primarily in rice paddies that mimic marshy wetland habitats and they are undiscriminating diners, eating everything from insects to small crabs and frogs.
The chemicals affected the birds and their food, and by 1981 just five wild toki remained in Japan, all on Sado, where officials took them into protective captivity.
But by bizarre coincidence, the same year a population of seven wild toki was discovered in a remote area of China's Shaanxi province, reviving hopes for the bird's survival.
Sado's captive birds failed to mate, but China's program had more success, and when then-Chinese president Jiang Zemin made a historic first state visit in 1998 he offered Japan the gift of a pair of toki.
You You and Yang Yang arrived the following year on first-class seats, producing their first chick months later in an event that led national television broadcasts.
Other birds arrived from China, and with time Sado had a large enough population to consider reintroducing the toki to the wild.
But first they had to tackle the use of chemical fertilizers and pesticides on Sado.
Officials initially struggled to persuade Sado farmers to switch to environmentally friendly fertilisers.
"Back then people didn't think about the environment when farming. Their priorities were selling products at a high price and harvesting as much as possible," said Shinichiro Saito, a 60-year-old rice farmer.
Farmers were asked to cut chemical fertilizers and pesticides by half from the level allowed by local rules, but there was pushback.
Fewer chemicals meant smaller harvests, lost income, and more weeding.
And some farmers couldn't see the point of other proposals like underground channels connecting rice fields to rivers to increase the flow of aquatic life.
'Toki-friendly'
Local officials used a carrot-and-stick approach, refusing to buy rice from farmers who rejected the new chemical limits and creating a new premium brand of "toki-friendly" rice for those who did.
But Saito, who was an early adopter, said the real difference came when the first birds were released in 2008.
The creation of a premium "toki-friendly" rice brand encouraged farmers to back conservation efforts.
"It was the toki that changed their minds," he said, with a lop-sided grin.
Even farmers reluctant to adapt were "delighted" to see a bird with almost mythical status on Sado wandering through their fields.
"This is a true story. The toki was almost like an environmental ambassador, it helped create a good environment for itself."
Tsuchiya's daily rounds began with the 2008 release.
He has since witnessed triumphs including the first wild-born chick, and the first chick born to wild-born birds—moments he describes with the proud anxiety of a parent sending a child off to school for the first time.
He still runs his own business, though the toki feather tucked into his car's folding mirror makes clear where his heart lies.
And the breeding program has continued, supplemented by birds from China that help broaden the gene pool.
Sado local Masaoki Tsuchiya documents toki nests each morning.
Around 20 birds are released twice a year after graduating from a three-month training program that prepares them for life outside a cage.
"They learn how to fly, how to find food and to get used to being around humans," explained Tomoki Tsuchiya, who works with Sado's local government to make the island toki-friendly.
City officials even farm around the birds to acquaint them with the sound.
'Like family'
When the first toki were released on Sado, there were so many gaps in knowledge about the species that volunteers analyzed their droppings to find out what the birds were eating.
There were missteps: officials prepared a remote mountain location for the release, believing the birds would prefer seclusion, but the toki instead flew down to fields that were frequented by farmers.
Tomoki Tsuchiya's interest in toki was fostered by his father, Masaoki.
Factfile on the Japanese crested ibis that went effectively extinct in the wild in Japan, but has been reintroduced over the course of two decades.
But it is a fascination shared by many on Sado, where the bird is rendered in cute mascot form on everything from T-shirts to milk cartons.
"How can I express it? The toki is so important for people on Sado," the 42-year-old said.
"It's like family."
Even after training, a toki's future is precarious: only about half survive predators like snakes and weasels, and the survival rate for newborn chicks is similar.
But enough have thrived that Japan may expand the Sado program, and there have been successes elsewhere.
In just under two decades, Sado's population of wild toki has gone from zero to nearly 500.
China's wild population now numbers over 4,450, and a South Korean project released 40 toki for the first time in 2019.
For Saito, who speaks as toki squawk nearby, the bird's resurrection is part of a bigger achievement on Sado—a new approach to farming and the environment.
"When this project started, what I dreamed of the most was seeing toki flying overhead while I farmed," he said.
"An environment that is good for toki is an environment that is also safe for humans, and that's something people on Sado can be proud of."
Spider silk properties analyzed for use as bio-based fibers in the medical field
by Shinshu University
Appearance of the native spider silk samples on stainless steel plate: (a) reeled fibers, (b) reeled fibers after removal of lipid layers, (c) films, and (d) non-woven fabrics. Credit: Langmuir
Silk has been cultivated for centuries by domesticated silkworms, but it has been difficult to commercially produce spider silk in bulk due to their cannibalistic tendencies. However, spider silk fibers are attracting attention for their fineness, mechanical properties, and lustrous appearance. Spider silk produced through recombinant protein expression systems and chemical synthesis has been shown to have superior properties for medical use to prevent the formation of blood clots and have excellent knot strength to endure repetitive loading and unloading. In this study, published in Langmuir, the cell adhesion behavior of native spider silk was investigated.
The development of cell culture substrates is indispensable for the progress of regenerative medicine. In conventional research, many cell culture substrates made of petroleum-derived polymers have been developed, but the development of protein-derived cell culture substrates has not made much progress. Among the protein-based materials, silkworm silk has been used since ancient times. In recent years, attention has been focused on spider-derived silk, which has better mechanical properties than silkworm silk. However, little is known about the cell behavior on spider silk. Therefore, for this study, researchers lead by Dr. Kenjiro Yazawa of Shinshu University aimed to investigate the cell adhesion behavior on spider silk.
In previous studies, experiments were conducted with recombinant spider silk-like proteins instead of natural spider silk. Therefore, the size of the protein was about 1/10 of that of natural spider silk. The research group that includes Dr. Jun Negishi, an expert in biomaterials believed that it is important to collect spider silk directly from live spiders and observe cell adhesion of natural spider silk.
TOC graphic. Credit: Langmuir
The researchers prepared three types of spider silk; reeled fibers, film, and nanofiber (non-woven fabric). It was challenging to wind live spider thread so that it would be oriented in the same direction. However, they were able to achieve this and found that there was a difference in the shape of cell adhesion among the three shapes of spider silk.
This study clarified the adhesion behavior of fibroblasts on spider silk, but it is still necessary to investigate whether there is a difference in cell activity depending on the surface topography. For example, if you know that the cell activity is high on a thread or non-woven fabric or that it is low on film, it will be a new finding. This aspect of native spider silk is currently under investigation.
More information: Kenjiro Yazawa et al, Cell Adhesion Behaviors on Spider Silk Fibers, Films, and Nanofibers, Langmuir (2022). DOI: 10.1021/acs.langmuir.2c00818
