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16 января, 20:36

In This Issue [This Week in PNAS]

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Perineuronal nets and recall of distant fear memories PNN (green) around a parvalbumin-expressing inhibitory neuron (red) in rat V2L. Perineuronal nets (PNN) are gauzy, carbohydrate-rich structures that envelop subsets of neurons in the central nervous system, forming a long-lived extracellular matrix that stabilizes synaptic connections between neurons. PNNs are thought...

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16 января, 20:36

Action of steroids and plant triterpenoids on CatSper Ca2+ channels in human sperm [Biological Sciences]

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The sperm-specific Ca2+ channel CatSper (cation channel of sperm) controls the intracellular Ca2+ concentration and, thereby, the swimming behavior of sperm. Human CatSper is activated by progesterone (1, 2), an oviductal hormone, which stimulates Ca2+ influx and motility responses. By patch-clamp recording from human sperm, Mannowetz et al. (3) studied...

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16 января, 20:36

Reply to Brenker et al.: The plant triterpenoid pristimerin inhibits calcium influx into human spermatozoa via CatSper [Biological Sciences]

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In the letter by Brenker et al. (1), the authors assessed actions of various steroids toward the human calcium channel of sperm (CatSper). The experiments, carried out with calcium imaging, are minimally supplemented by electrophysiology. The authors show that all tested steroids activate CatSper with different efficiencies. However, the plant...

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16 января, 20:36

Considering hypertonicity in the interpretation and analysis of cell type-specific gene expression pattern in the collecting duct [Biological Sciences]

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The different parts of the renal nephron have different functions that are related to reabsorption or secretion processes. This is mediated by genes that show a distinct expression pattern along the renal nephron segments (1). The majority of the segments contain only one epithelial cell type. However, the collecting duct...

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16 января, 20:36

Reply to Edemir: Physiological regulation and single-cell RNA sequencing [Biological Sciences]

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Tacitly, Edemir (1) points to an important issue in the interpretation of data from single-cell RNA-sequencing experiments. Any given cell can exist in a variety of regulatory states that are affected both by extracellular signals and the prior history of the cell. Consequently, data from single-cell RNA sequencing, such as...

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16 января, 20:36

Profile of David M. Sabatini [Profile]

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As a young doctoral candidate at the Johns Hopkins University School of Medicine, David M. Sabatini was allowed to choose his own research project for his thesis. He chose to investigate the molecular mechanism of rapamycin, a compound with antifungal, antitumor, and immunosuppressant properties. The decision was pivotal, because Sabatini...

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16 января, 20:36

Profile of Joachim Frank, Richard Henderson, and Jacques Dubochet, 2017 Nobel Laureates in Chemistry [Profile]

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In 2017, the Nobel Prize in Chemistry was awarded to three key pioneers in the birth and development of cryoelectron microscopy (cryo-EM): Jacques Dubochet, Joachim Frank, and Richard Henderson. As a starting graduate student in England, moving from physics to biology and the study of macromolecular structure, I had the...

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16 января, 20:36

Microbial proteins for organic material degradation in the deep ocean [Ecology]

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Organic material is synthesized in the sunlit surface layer of the oceans and that is where most of it is decomposed back to carbon dioxide and other inorganic constituents. However, a small fraction escapes immediate degradation and makes its way into deeper waters, some as far as the bottom thousands...

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16 января, 20:36

Endless skulls most beautiful [Evolution]

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The amazing disparity of living birds is self-apparent, yet immensely challenging to fully quantify. After all, birds are represented by nearly 11,000 living species, comprising a mind-boggling spectrum of shapes, sizes, and colors (1). This incredible variability manifests in an incalculable number of ways (from habitat type to diet to...

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16 января, 20:36

Searching for the neural causes of criminal behavior [Neuroscience]

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All behavior is proximally caused by the brain, but the neural causes of most complex behaviors are still not understood. Much of our ignorance stems from the fact that complex behavior depends on distributed neural control. Unlike a reflex, where the arc from sensation to action can be traced through...

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16 января, 20:36

Dynamics and mechanisms of intracellular calcium waves elicited by tandem bubble-induced jetting flow [Engineering]

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One of the earliest events in cellular mechanotransduction is often an increase in intracellular calcium concentration associated with intracellular calcium waves (ICWs) in various physiologic or pathophysiologic processes. Although cavitation-induced calcium responses are believed to be important for modulating downstream bioeffects such as cell injury and mechanotransduction in ultrasound therapy,...

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16 января, 20:36

Creation of disease-inspired biomaterial environments to mimic pathological events in early calcific aortic valve disease [Engineering]

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An insufficient understanding of calcific aortic valve disease (CAVD) pathogenesis remains a major obstacle in developing treatment strategies for this disease. The aim of the present study was to create engineered environments that mimic the earliest known features of CAVD and apply this in vitro platform to decipher relationships relevant...