When London-based student Lewis Hornby noticed that his dementia-afflicted grandmother was having trouble staying hydrated, he came up with Jelly Drops, bite-sized pods of edible water made with gelling agents and electrolytes.
As sponges and ctenophores are such disparate animals13, the nature of the first diverging animal lineage has implications for the evolution of fundamental animal characteristics. Adult sponges are generally sessile filter-feeding organisms with body plans organized into reticulated water-filtration channels, structures built out of silica or calcium carbonate, and specialized cell types and tissues used for feeding, reproduction and self-defence, but they lack neuronal and muscle cells15. By contrast, ctenophores are gelatinous marine predators that move using eight longitudinal ‘comb rows’ of ciliary bundles16,17; they are superficially similar but unrelated to cnidarian medusae13,18 and possess multiple nerve nets19. Thus, whereas the sponge-sister scenario suggests a single origin of neurons on the ctenophore–parahoxozoan stem, the ctenophore-sister scenario implies either that either ancestral metazoan neurons were lost in the sponge lineage, or that there was convergent evolution of neurons in the ctenophore and parahoxozoan lineages3,6. Similar considerations apply to other metazoan cell types18, gene regulatory networks, animal development13,18 and other uniquely metazoan features.
Despite its importance for understanding animal evolution, the relative branching order of sponges, ctenophores and other animals has proven to be difficult to resolve2. The fossil record is largely silent on this issue as verified Precambrian sponge fossils are extremely rare20 and putative fossils of the soft-bodied ctenophores are difficult to interpret21. Morphological characters of living groups (for example, choanocytes of sponges) are not sufficient to resolve the question because true homology is difficult to assign, and such characters are easily lost or can arise convergently13,22. The ctenophore-sister hypothesis is supported by a pair of gene duplications shared by sponges, bilaterians, placozoans and cnidarians but not ctenophores23. Although sophisticated methods for sequence-based phylogenomics have been developed and applied to increasingly large molecular datasets, there is still considerable debate about the relative position of sponges and ctenophores as results are sensitive to how sequence evolution is modelled11, which taxa or sites are included24,25, and the effects of long-branch artifacts and nucleotide compositional variation26. New approaches are needed.
We reasoned that patterns of synteny, classically defined as chromosomal gene linkage without regard to gene order27, could provide a powerful tool for resolving the ctenophore-sister versus sponge-sister debate. Chromosomal patterns of gene linkage evolve slowly in many lineages12,28,29,30, probably because it is improbable for interchromosomal translocations to be fixed in populations with large effective population sizes28,31,32. Notably, some changes in synteny are effectively irreversible. For example, when two distinct ancestral synteny groups are combined onto a single chromosome by translocation, and subsequent intrachromosomal rearrangements mix these two groups of genes, it is very unlikely that the ancestral separated pattern will be restored by further rearrangement and fission, in the same sense that spontaneous reduction in entropy is improbable12. Such rare and irreversible changes are particularly useful for resolving challenging phylogenetic questions as they give rise to shared derived features that unambiguously unite all descendant lineages33,34,35. Deeply conserved syntenies observed between animals and their closest unicellular relatives12 suggest that outgroup comparisons could be used to infer ancestral metazoan states and polarize changes within animals to address the sponge-sister versus ctenophore-sister debate. Yet, chromosome-scale genome sequences of the unicellular or colonial eukaryotic outgroups closest to animals (choanoflagellates, filastereans and ichthyosporeans) have not been reported.
Quantum effects improve the performance of magnetic induction tomography—an imaging technique that has promising medical applications.
😗 year 2017.
Certain treatments for patients suffering from chronic diseases, such as inflammatory bowel diseases, require multiple intravenous or subcutaneous injections of specific drugs. Because of the pain and anxiety associated with needles, some patients stop adhering to these treatments.
MIT spinout Portal Instruments has now landed a commercialization deal for a smart, needle-free injection device that could reduce the pain and anxiety associated with needle injections, shorten administration time, and improve patient adherence.
Continue reading “Startup’s needle-free drug injector gets commercialization deal” »
Researchers develop cutting-edge therapy that targets Candida albicans while preserving vaginal microbiota | Drug Discovery And Development.
EPFL researchers have created novel protein binders that can seamlessly attach to important targets, including the spike protein of SARS-CoV-2.
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the official name of the virus strain that causes coronavirus disease (COVID-19). Previous to this name being adopted, it was commonly referred to as the 2019 novel coronavirus (2019-nCoV), the Wuhan coronavirus, or the Wuhan virus.
Vital funding supports’s exciting and lifechanging work on Total Artificial Heart for the first in human early feasibility studies.
Last week, US-Israeli startup SIRTLab announced the appointment of leading geroscience researcher Nir Barzilai as its Chief Medical Adviser. The company is focused on the development of therapeutics that boost levels of a key protein called sirtuin 6 (SIRT6), which is heavily implicated in longevity.
Sirtuins are a group of proteins found in all living organisms, including humans, that play a vital role in regulating various cellular processes. There are seven different types of sirtuins, numbered from SIRT1 to SIRT7, each with its own unique functions. In recent years, SIRT6 has gained particular attention for its potential role in promoting healthy aging, and SIRTLab has put the protein at the center of its work.
Longevity. Technology: The SIRT6 protein has been shown to regulate several critical cellular pathways, including glucose metabolism, DNA repair and inflammation – all of which play key roles in aging and longevity. One of the world’s leading authorities on SIRT6 is SIRTLab co-founder and Bar-Ilan University professor Haim Cohen, whose research is behind the company’s work to develop therapeutics with longevity-boosting potential. To learn more about SIRTLab’s longevity-first approach, we spoke to its co-founder and CEO Boaz Misholi.
A new study adds to an emerging, radically new picture of how bacterial cells continually repair faulty sections of their DNA.
Published online May 16 in the journal Cell, the report describes the molecular mechanism behind a DNA repair pathway that counters the mistaken inclusion of a certain type of molecular building block, ribonucleotides, into genetic codes. Such mistakes are frequent in code-copying process in bacteria and other organisms. Given that ribonucleotide misincorporation can result in detrimental DNA code changes (mutations) and DNA breaks, all organisms have evolved to have a DNA repair pathway called ribonucleotide excision repair (RER) that quickly fixes such errors.
Last year a team led by Evgeny Nudler, Ph.D., the Julie Wilson Anderson Professor in the Department of Biochemistry and Molecular Pharmacology at NYU Langone Health, published two analyses of DNA repair in living E. coli cells. They found that most of the repair of certain types of DNA damage (bulky lesions), such as those caused by UV irradiation, can occur because damaged code sections have first been identified by a protein machine called RNA polymerase. RNA polymerase motors down the DNA chain, reading the code of DNA “letters” as it transcribes instructions into RNA molecules, which then direct protein building.
