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Does a prospective father’s gut microbiota matter?

Germline cells play a key role in the transmission of phenotypes and physiological adaptations to subsequent generations (1). Over a century ago, August Weismann proposed that changes in somatic cells cannot be passed on to germ cells or offspring, a theory known as the Weismann barrier (2). Nevertheless, recent studies have proven that the Weismann barrier is permeable, and information can pass from soma to germline and modulate offspring phenotypes. In the past decade, there has been tremendous interest and progress in understanding how an altered microbiome (dysbiosis) affects different somatic cells that compose body tissues, such as brain, liver, heart, kidney, and lungs (3). Nevertheless, whether gut microbiome dysbiosis can exert an influence on the mammalian germline cells (i.e., gut to germline), and ultimately nonexposed offspring, remains unclear.

To tackle this research question, my colleagues and I established an inducible model of gut microbiota dysbiosis in isogenic male mice, using ad lib nonabsorbable antibiotics (nABX) that cannot cross the epithelial barrier of the gut (4). As expected, 6 weeks of low-dose nABX treatment led to a physiologically significant dysbiosis, which is reversible and gradually normalized to a physiologically healthy gut microbiota after 8 weeks of nABX withdrawal (6 weeks + 8 recovery). The induced dysbiosis after 6 weeks of nABX had no appreciable effects on male body weight, growth, or fertility. No nABx residues were detected in the serum or testes of treated males, which confirmed that any distal tissue responses are gut dysbiosis–induced rather than systemic drug effects.

We then examined physiological changes in the male reproductive system in response to 6 weeks of dysbiosis. Dysbiotic males had smaller testes, lower sperm count, and more abnormally shaped sperm. Histological analysis uncovered a wide range of anatomical abnormalities in testes of dysbiotic males, including increased number of abnormal seminiferous tubules, reduced epithelial thickness, and absence of mitotic compartments, which were not observed in control testes. Testicular metabolomic profiles revealed that testes clustered according to gut microbiota status and exhibited dysregulated sphingolipids, glycerophospholipids, and endocannabinoids, all known to play pivotal roles in germ cell function. Moreover, in dysbiotic male testes, spermatogenesis-regulating genes were misexpressed—most notably leptin, a reproductive hormone, was strongly down-regulated.

Hans Bethe — Biographical

Hans Albrecht Bethe was born in Strasbourg, Alsace-Lorraine, on July 2 1906. He attended the Gymnasium in Frankfurt from 1915 to 1924. He then studied at the University of Frankfurt for two years, and at Munich for two and one half years, taking his Ph. D. in theoretical physics with Professor Arnold Sommerfeld in July 1928.

He then was an Instructor in physics at Frankfurt and at Stuttgart for one semester each. From fall 1929 to fall 1933 his headquarters were the University of Munich where he became Privatdozent in May 1930. During this time he had a travel fellowship of the International Education Board to go to Cambridge, England, in the fall of 1930, and to Rome in the spring terms of 1931 and 1932. In the winter semester of 1932–1933,he held a position as Acting Assistant Professor at the University of Tubingen which he lost due to the advent of the Nazi regime in Germany.

Bethe emigrated to England in October 1933 where he held a temporary position as Lecturer at the University of Manchester for the year 1933–1934, and a fellowship at the University of Bristol in the fall of 1934. In February 1935 he was appointed Assistant Professor at Cornell University, Ithaca, N. Y. U.S.A., then promoted to Professor in the summer of 1937. He has stayed there ever since, except for sabbatical leaves and for an absence during World War II. His war work took him first to the Radiation Laboratory at the Massachusetts Institute of Technology, working on microwave radar, and then to the Los Alamos Scientific Laboratory which was engaged in assembling the first atomic bomb. He returned to Los Alamos for half a year in 1952. Two of his sabbatical leaves were spent at Columbia University, one at the University of Cambridge, and one at CERN and Copenhagen.

Babies’ poor vision may help organize visual brain pathways

Incoming information from the retina is channeled into two pathways in the brain’s visual system: one that’s responsible for processing color and fine spatial detail, and another that’s involved in spatial localization and detecting high temporal frequencies. A new study from MIT provides an account for how these two pathways may be shaped by developmental factors.

Newborns typically have poor visual acuity and poor vision because their retinal cone cells are not well-developed at birth. This means that early in life, they are seeing blurry, color-reduced imagery. The MIT team proposes that such blurry, color-limited vision may result in some specializing in low spatial frequencies and low color tuning, corresponding to the so-called magnocellular system. Later, with improved vision, cells may tune to finer details and richer color, consistent with the other pathway, known as the parvocellular system.

To test their hypothesis, the researchers trained computational models of vision on a trajectory of input similar to what human babies receive early in life—low-quality images early on, followed by full-color, sharper images later. They found that these models developed processing units with receptive fields exhibiting some similarity to the division of magnocellular and parvocellular pathways in the human visual system. Vision models trained on only high-quality images did not develop such distinct characteristics.

Rare kidney cancer resists immune therapies due to lack of active T-cells

Cancer-fighting T-cells, the immune system’s primary enforcers, are scarce in the rare kidney cancer called chromophobe renal cell carcinoma (ChRCC) and those that are present are indifferent to the tumor threat and traditional immune therapies, revealing the need for new targets and treatments.

Those are among the results described in a July 2 published report in the Journal of Clinical Oncology that set out to understand the biology of certain tumors, including ChRCC, and their immune responses.

The study found that ChRCC, which accounts for about 5% of all kidney cancers, has fewer T-cells and key molecules required for an than other kidney cancers and poorer response and when treated with immune-based therapies. Other examined kidney tumors included in the study were low-grade oncocytic (LOT) and the usually benign renal oncocytoma (RO).

Physicists create tunable system for enhanced quantum sensing

Researchers at the Niels Bohr Institute, University of Copenhagen, have developed a tunable system that paves the way for more accurate sensing in a variety of technologies, including biomedical diagnostics. The result is published in Nature.

The potential range of technologies is large, stretching from the largest to smallest scales, from detecting gravitational waves in space to sensing the tiny fluctuations in our own bodies.

Optical sensing technologies are already part of everyday life. In recent years, advances in have pushed the sensitivity of these devices closer to the so-called standard quantum limit—a practical boundary that arises from the inevitable noise arising from measuring on the smallest scales.

AI and biophysics unite to forecast high-risk viral variants before outbreaks

When the first reports of a new COVID-19 variant emerge, scientists worldwide scramble to answer a critical question: Will this new strain be more contagious or more severe than its predecessors? By the time answers arrive, it’s frequently too late to inform immediate public policy decisions or adjust vaccine strategies, costing public health officials valuable time, effort, and resources.

In a pair of recent publications in Proceedings of the National Academy of Sciences, a research team in the Department of Chemistry and Chemical Biology combined biophysics with artificial intelligence to identify high-risk viral variants in record time—offering a transformative approach for handling pandemics. Their goal: to get ahead of a virus by forecasting its evolutionary leaps before it threatens public health.

“As a society, we are often very unprepared for the emergence of new viruses and pandemics, so our lab has been working on ways to be more proactive,” said senior author Eugene Shakhnovich, Roy G. Gordon Professor of Chemistry. “We used fundamental principles of physics and chemistry to develop a multiscale model to predict the course of evolution of a particular variant and to predict which variants will become dominant in populations.”

Growing evidence for evolving dark energy could inspire a new model of the universe

The birth, growth and future of our universe are eternally fascinating.

In the last decades, telescopes have been able to observe the skies with unprecedented precision and sensitivity.

Our research team on the South Pole Telescope is studying how the universe evolved and has changed over time. We have just released two years’ worth of mapping of the infant universe over 1/25th of the sky.

Unlocking the mystery behind Barrett’s esophagus

A team led by researchers at Baylor College of Medicine and Washington University School of Medicine has shed light on the process that drives Barrett’s esophagus formation. This condition affects the lining of the esophagus—the tube that carries food from the mouth to the stomach—and increases the risk of developing esophageal adenocarcinoma, a serious and often deadly cancer.

The study, published in the Journal of Clinical Investigation, reveals that two important genes involved in guiding and maintaining the identity of the esophagus and intestine, SOX2 and CDX2, are altered in Barrett’s esophagus. The findings not only deepen our understanding of how the disease develops but also open the door to new ways of identifying people at risk and potentially preventing the condition from progressing to cancer.

“Esophageal adenocarcinoma is one of the fastest growing solid cancers. It is difficult to treat, and there are no effective screening techniques available,” said first and co-corresponding author Dr. Ramon Jin, assistant professor in the John T. Milliken Department of Medicine at Washington University.

Extraterrestrial Habitats: Bioplastics for Life Beyond Earth

If humans are ever going to live beyond Earth, they’ll need to construct habitats. But transporting enough industrial material to create livable spaces would be incredibly challenging and expensive. Researchers at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) think there’s a better way, through biology.

An international team of researchers led by Robin Wordsworth, the Gordon McKay Professor of Environmental Science and Engineering and Professor of Earth and Planetary Sciences, have demonstrated that they can grow green algae inside shelters made out of bioplastics in Mars-like conditions. The experiments are a first step toward designing sustainable habitats in space that won’t require bringing materials from Earth.

In lab experiments that recreated the thin atmosphere of Mars, Wordsworth’s team grew a common type of green algae called Dunaliella tertiolecta. The algae thrived inside a 3D-printed growth chamber made from a bioplastic called polylactic acid, which was able to block UV radiation while transmitting enough light to allow the algae to photosynthesize.

The algae was kept under a Mars-like 600 Pascals of atmospheric pressure – over 100 times lower than Earth’s — and in a carbon dioxide-rich environment, as opposed to mostly nitrogen and oxygen like on Earth. Liquid water cannot exist at such low pressures, but the bioplastic chamber created a pressure gradient that stabilized water within it. The experiments point to bioplastics as potentially key to creating renewable systems for maintaining life in a lifeless environment.

The concept the researchers demonstrated is closer to how organisms grow naturally on Earth, and it contrasts with an industrial approach using materials that are costly to manufacture and recycle.