The Effect of Bovine Serum Albumin and Cytohelicase on Surface-Spread Synaptonemal Complexes of Rye (Secale Cereale)

Synaptonemal complexes of rye meiocytes were spread on plastic coated slides for electron microscopic observation. Two proteins generally used in synaptonemal complex spreading techniques, bovine serum albumin and cytobelicase, were applied separately or in combination in an isotonic protoplast medium at concentrations of 0.1-5%. At high concentrations these proteins proved to enhance notably the ultimate number of cells with synaptonemal complexes in the preparations. Also under this condition, centromere structures became stainable with silver nitrate in both the synaptonemal complexes of pollen mother cells and in interphase nuclei of other cell types. Since the true action of cytohelicase under appropriate spreading conditions was uncertain, the putative enzymatic digestion of cell walls was determined in a series of experiments using the fluorochrome calcofluor white as a stain of callose walls. Obvious breakdown of the cell walls was not observed before 8 min of treatment under standard conditions. This made it plausible that the prime effect of cytohelicase is that of a nonspecific protein interacting with the chromatin and improving the adhesion of synaptonemal complexes to the hydrophobic plastic film. The differential staining of the centromere structures in the presence of bovine serum albumin and cytohelicase probably reflects a reduced spreading of these structures due to preferential binding between these proteins and centromeric proteins.     

Fluorescence for biological logic gates

Biological logic gates are smart probes able to respond to biological conditions in behaviors similar to computer logic gates, and they pose a promising challenge for modern medicine. Researchers are creating many kinds of smart nanostructures that can respond to various biological parameters such as pH, ion presence, and enzyme activity. Each of these conditions alone might be interesting in a biological sense, but their interactions are what define specific disease conditions. Researchers over the past few decades have developed a plethora of stimuli‐responsive nanodevices, from activatable fluorescent probes to DNA origami nanomachines, many explicitly defining logic operations. Whereas many smart configurations have been explored, in this review we focus on logic operations actuated through fluorescent signals. We discuss the applicability of fluorescence as a means of logic gate implementation, and consider the use of both fluorescence intensity as well as fluorescence lifetime.     

Autotrophic CO2 fixation in Acetobacterium woodii

Earlier labeling experiments have shown that autotrophically grown Acetobacterium woodii assimilates cell carbon via direct acetyl CoA formation from 2 CO₂, rather than via the Calvin cycle. Cell extracts contained the enzymes required for biosynthesis starting from acetyl CoA and CO₂. Notably, pyruvate synthase, pyruvate phosphate dikinase, and phosphoenolpyruvate carboxytransphosphorylase were present in sufficiently high activities. Ribulose-1,5-bisphosphate carboxylase activity could not be detected. The observed enzyme pattern was consistent with the postulated biosynthetic pathway as deduced from ¹⁴C-labeling experiments.     

Proteolysis of human C-reactive protein by neutrophil-derived lysosomal enzymes generates peptides which modulate neutrophil function: Implication to the anti-inflammatory mechanism

Summary Proteolysis of human C-reactive protein (CRP) by lysosomal enzymes derived from human neutrophils is shown to yield short peptides capable of modulating the production of superoxide ions by stimulated human neutrophils. Thus, fractionation of trichloroacetic acid-soluble digestion mixtures by HPLC yielded the following peptides: Ser-Tyr (1), Gly-Tyr (2), Phe-Glu-Val-Pro-Glu-Val-Thr (3), Trp-Asp-Phe-Val (4), Asn-Met-Trp-Asp-Phe-Val (5) and Gln-Leu-Trp-Pro (6). These peptides, corresponding to CRP sequences 18–19, 48–49 and/or 72–73, 84–90, 162–165, 160–165 and 203–206, respectively, have been synthesized and peptides 2, 3 and in particular peptide 6 were found to significantly inhibit neutrophilic function. The results suggest that CRP-derived peptides may be capable of regulating superoxide ion production by neutrophils in vivo during the acute phase response as part of a complex protective mechanism.     

Bacterial viability assessment by flow cytometry analysis in soil

Soil microhabitats and their heterogeneity are often considered to be among the most important factors affecting soil biotic communities. The microbial community has become one of the most important links in soil nutrient cycles and trophic components due to its role in biological processes, spatial and temporal dynamics, and physiological adaptation. Sandy-soil desert systems are characterized by fast water infiltration during the rainy season, high salinity, and low moisture availability in the upper soil layers. Plants have developed different ecophysiological adaptations in order to cope with this harsh environment. The Tamarix aphylla is known to be one of the most commonly adapted plants, exhibiting a mechanism for secretion of excess salts as aggregates through its leaves. These leaves aggregate beneath the plant, creating ‘islands of salinity’. Soil biotic components are, therefore, exposed to extreme abiotic stress conditions in this niche. The goal of this study was to examine the effect of T. aphylla on the live/dead bacterial population ratio on a spatial and temporal scale. The results emphasize the effect of abiotic factors, which changed on temporal as well as spatial scales, and also on the size of the active soil bacterial community, which fluctuated between 1.44% and 25.4% in summer and winter, respectively. The results of this study elucidate the importance of moisture availability and the ‘island-of-salinity’ effect on the active microbial community in a sandy desert system.     

Single-Cell Sequencing of Brain Cell Transcriptomes and Epigenomes

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NDNF interneurons in layer 1 gain-modulate whole cortical columns according to an animal’s behavioral state

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Pathological factors underlying hyperthermia

Hyperthermia is the result of an imbalance between total heat (metabolic heat and environmental heat) accumulated in the body and heat loss from the body, and is defined as a condition when core temperature rises above its normal range. This article will present an overview of syndromes associated with hyperthermia, through discussion of the etiology and pathophysiologic mechanisms that underlie those disorders. Emphasis will also be placed on the therapeutic measures to be taken in order to avert the complications of these disorders.