Hexbyte Glen Cove Discovered: How ladybugs stick to surfaces without losing legs at takeoff thumbnail

Hexbyte Glen Cove Discovered: How ladybugs stick to surfaces without losing legs at takeoff

Hexbyte Glen Cove

Figure 1. Ladybird beetle on a glass surface. Its white tarsal setae can be seen in contact with the surface. Credit: National Institute for Materials Science

NIMS, the University of Tokyo and the University of Kiel have jointly ascertained the tarsal adhesion mechanisms employed by ladybird beetles, which had been debated for decades.

Strong adhesives are commonly used to firmly bond materials together. Their use hinders recycling—one of our efforts to build a sustainable society—by making it more difficult to disassemble and sort waste products. Efforts are therefore underway to develop new, environmentally friendly adhesive technologies that have high bonding strength but are also easier to detach. Some scientists in biomimetics have been studying the ability of reptiles and insects to easily walk on ceilings and walls by quickly and repeatedly attaching and detaching their tarsi to and from these surfaces. This research team has been researching and developing new adhesive technologies using the efficient tarsal functions of ladybird beetles as a model. This beetle is capable of walking on glassy, smooth surfaces without slipping despite the fact that the portion of its tarsi which comes into contact with the surface is covered with rigid setae. This portion of the tarsi also secretes fluid. Based on these observations, two potential tarsal adhesion mechanisms had been proposed: a mechanism involving intermolecular forces of attraction between tarsal setae and the walking surface and another mechanism involving the of the secreted tarsal fluid. The debate over which was correct remained unresolved for 40 years.

This research team recently succeeded in measuring the thickness of the tarsal fluid layer formed between the setal tips of a ladybird beetle and the glass surface on which the beetle was placed, under the presumption that this thickness indicates the strength of the intermolecular of attraction between the tarsi and the surface. To make this measurement, the team first formed an AuPd particle layer 10 to 20 nm in thickness on the glass surface. The beetle was then placed on the coated surface and allowed to secrete tarsal fluid. The tarsal fluid was then instantaneously frozen while the beetle’s legs were still resting on the coated surface. The legs were then detached from the surface and the height of the AuPd particle layer filled with the frozen tarsal fluid was measured under a Cryo-SEM microscope. As a result, the thickness of the tarsal layer (i.e., the distance between the setal tips of the beetle and the glass ) was found to be sufficiently narrow for intermolecular forces of attraction to act effectively. The team then measured traction forces of ladybird beetles walking on the surfaces of various substrates using a combination of biomimetic and materials science techniques in order to determine the relative contributions of intermolecular forces and other adhesion forces. Intermolecular forces are known to be correlated with work of adhesion (WA), the amount of energy required to separate two connected surfaces of different materials. The correlation between WA and traction forces was therefore examined by fitting experimental data into a mathematical formula describing the relationship between these two parameters. As a result, the tarsal adhesion force of the beetle was found to be correlated with WA, indicating that intermolecular forces (i.e., van der Waals forces) are the primary force involved in the tarsal adhesion of ladybird beetles.

In future studies, the team plans to apply these results to the development of artificial structures capable of attaching and detaching themselves to and from various substrates. These structures may be used in the feet of disaster relief robots capable of traveling on various surfaces in a manner similar to ladybird beetles. They also may be integrated into devices designed to replace parts within high-precision equipment.

This research was published in the April 8, 2021 issue of Scientific Reports.



More information:
Naoe Hosoda et al, Evidence for intermolecular forces involved in ladybird beetle tarsal setae adhesion, Scientific Reports (2021). DOI: 10.1038/s41598-021-87383-9

Citation:
Discovered: How ladybugs stick to surfaces without losing legs at takeoff (2021, June 23)
retrieved 23 June 2021

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Hexbyte Glen Cove Newly discovered Miocene biome sheds light on rainforest evolution thumbnail

Hexbyte Glen Cove Newly discovered Miocene biome sheds light on rainforest evolution

Hexbyte Glen Cove

Selected plant taxa from the Zhangpu biota. Credit: NIGPAS

An international research group led by Prof. Wang Bo and Prof. Shi Gongle from the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences (NIGPAS) has collected approximately 25,000 fossil-containing amber samples and about 5,000 fossil plants in Zhangpu County, Fujian Province, southeast China from 2010 to 2019.

Their findings were published in Science Advances on April 30.

The Zhangpu biota, including amber biota and co-occurring megafossils, is the richest tropical seasonal biota discovered so far. It reveals that extraordinary species diversity existed within a 14.7 million-year-old tropical rainforest and sheds light on the evolution of the rainforest.

Diverse winged fruits of Dipterocarpaceae and legumes, as well as leaves of 78 different broadleaf trees show that tropical seasonal rainforests extended further north than today, offering an insight into what changes might take place in a future warmer world if ecosystems are able to adapt.

The Zhangpu amber biota contains a diverse, exquisitely preserved fossil arthropod fauna and abundant botanical and other inclusions such as fungi, snails, and even feathers. Botanical inclusions include bryophytes (liverworts and mosses) and flowering plants.

Arthropod inclusions cover an impressive array of more than 250 families including various spiders, mites, millipedes, and at least 200 families of insects in 20 orders. The extremely high variety of arthropods renders the Zhangpu amber biota one of the world’s four richest, along with the widely known Cretaceous Burmese amber biota (> 568 families), Eocene Baltic amber biota (> 550 families), and Miocene Dominican amber biota (205 families).

Representative inclusions in Zhangpu amber. Credit: NIGPAS

The insect fauna in Zhangpu amber include many ants, bees, lacewings, stick insects, termites, and grasshoppers that are today restricted to tropical Southeast Asia and/or New Guinea.

“The most unexpected finding is that the high diversity of ants and springtails all belong to living genera. In addition, the vast majority of previously identified insects in Zhangpu amber, such as bark lice, grasshoppers, beetles, and bees, also belong to living genera,” said Prof. Wang.

These results suggest that Asian rainforest insect communities have remained stable since the middle Miocene (at least 15 million years ago). It also highlights that tropical rainforests act as museums of biological diversity at the generic level. The relative ecological stability of such “megathermal” environments facilitates the continued accumulation of species diversity and makes them even more precious than previously realized.

The Zhangpu amber biota is unique because the samples are not commercially extracted and consequently the species census is minimally skewed by human selective bias. Moreover, its precise age is well-constrained by radioisotopic dating and the associated plant compression/impression fossils allow quantitative reconstruction of the ancient climate.

Ecological reconstruction of the Zhangpu biota. Credit: NIGPAS

Compared to the modern climate of Zhangpu, the most notable difference is that the middle Miocene climate had a warmer winter, leading to a relatively stable temperature throughout the year.

In scenarios of global warming, winter warming is commonly more pronounced than summer warming, and has larger and more widespread effects on terrestrial and marine ecosystems. It reduces “winterkills” and is beneficial for reproduction and growth of tropical animals and plants.

“Winter warming is likely to have been a major driver of the northern expansion of the megathermal biota in South China during the Mid-Miocene Climatic Optimum,” said Prof. Shi.



More information:
“The mid-Miocene Zhangpu biota reveals an outstandingly rich rainforest biome in East Asia” Science Advances (2021). DOI: 10.1126/sciadv.abg0625

Citation:
Newly discovered Miocene biome sheds light on rainforest evolution (2021, April 30)
retrieved 3 May 2021
from https://phys.org/news/2021-04-newly-miocene-biome-rainforest-evolution.html

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part may be reproduced without the written permission. The content is provided for information purposes only.

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Hexbyte Glen Cove Key steps discovered in production of critical immune cell thumbnail

Hexbyte Glen Cove Key steps discovered in production of critical immune cell

Hexbyte Glen Cove

dendritic cells stained by PS100 was found in corneal epithelium. Credit: Zhiguo.he

WEHI researchers have uncovered a process cells use to fight off infection and cancer that could pave the way for precision cancer immunotherapy treatment.

Through gaining a better understanding of how this process works, researchers hope to be able to determine a way of tailoring immunotherapy to better fight .

Led by Dr. Dawn Lin and Dr. Shalin Naik and published in Nature Cell Biology, the research provides new insight into the way cells adapt to fight .

This research lays the foundation for future studies into the body’s response to environmental stressors, such as injury, infection or cancer, at a single cell level.

Flt3L hormone plays vital role in fighting off infection

Dendritic cells are that activate ‘killer’ T cells, which are vital for clearing viral infections, such as COVID-19, but also for triggering a response to cancers such as melanoma and bowel cancer.

The Flt3L hormone can increase dendritic cell numbers, helping the immune system to fight off cancer and infection.

Dr. Naik and his team studied developing immune cells at a single cell level to gain a deeper understanding of how the body uses these cells to trigger immune responses.

“There is one type of dendritic cell that the body uses to fight some infections and cancer. The Flt3L hormone increases numbers of this particular dendritic cell. We know quite well how the dendritic cell fights the cancer, but we don’t know how the Flt3L hormone increases the numbers of those dendritic cells,” he said

Single-cell barcoding provides vital clues to how dendritic cells function

Researchers used a single-cell ‘barcoding’ technique to uncover what happened when dendritic cells multiplied.

“By using cellular barcoding—where we insert short synthetic DNA sequences, we call barcodes inside cells—we were able to determine which cells produced dendritic cells in pre-clinical models,” Dr. Naik said.

“As a result of this research, we now better understand the actions of the Flt3L hormone that is currently used in cancer immunotherapy trials, and how it naturally helps the body fight cancer and infection. This is a first step to design better precision immunotherapy treatments for cancer.”

Using single cell technology to improve immunotherapy treatment

This research answers a 50-year-long question as to what causes a stem cell to react in response to immense stress, such as infection or inflammation.

“We have known that the Flt3L hormone increases the number of for decades but now there is a focus on applying this knowledge to cancer immunotherapy and potentially to infection immunotherapy as well,” Dr. Naik said.

“The next stage in our research is to create ‘dendritic cell factories’ using our new knowledge, to produce millions to billions of these infection fighting and then use those in immunotherapy treatments.”

“These findings are a vital first step to improving treatments for patients, to help them better fight cancer and infection.”



More information:
Dawn S. Lin et al. Single-cell analyses reveal the clonal and molecular aetiology of Flt3L-induced emergency dendritic cell development, Nature Cell Biology (2021). DOI: 10.1038/s41556-021-00636-7

Citation:
Key steps discovered in production of critical immune cell (2021, March 2)
retrieved 3 March 2021
from https://phys.org/news/2021-03-key-production-critical-immune-cell.html

This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no
pa

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