Virus present in the reproductive tract of asymptomatic drones of honey bee (Apis mellifera l.), and possible infection of queen during mating

Virus particles and viral inclusions were detected by transmission electron microscopy examination of sections of the seminal vesicles and mucus gland of asymptomatic young drones from colonies of Apis mellifera lightly infested by Varroa mite. In the mucus gland the infection was found in the muscular sheath and epithelium, while in the seminal vesicle in cells of the outer serosa. Isolated viral particles were also observed in the hemolymph occupying the intercellular spaces of the muscular sheath fibers. In the muscle the virus appeared as polygonal crystalloid inclusions, while in the epithelium mainly inside cytoplasmic vesicles. The infected cells apparently are not damaged. The virus particles are present in the hemolymph and forming more mature structures, as crystalloids, in the muscle. This suggests that the virus is liberated in the body fluid and infects the tissues penetrating the cells through endocytosis. The presence of virus in mucus gland epithelial vesicles raise the possibility of its transference to the gland secretion and therefore, to the semen.     

基于可编程控制器的调胶控制系统设计

本文介绍了调胶控制系统的组成和工作原理,着重叙述了三菱PLC与LEODO人机界面结合的控制方式,使系统的性能得到较大的提高,系统投入运行后取得了良好的经济效益。     

Shedding Light on the Trehalose‐Enabled Mucopermeation of Nanoparticles with Label‐Free Raman Spectroscopy

Nanoparticle‐based drug delivery systems have attracted significant interest owing to their promise as tunable platforms that offer improved intracellular release of cargo therapeutics. However, significant challenges remain in maintaining the physiological stability of the mucosal matrix due to the nanoparticle‐induced reduction in the matrix diffusivity and promotion of mucin aggregation. Such aggregation also adversely impacts the permeability of the nanoparticles, and thus, diminishes the efficacy of nanoparticle‐based formulations. Here, an entirely complementary approach is proposed to the existing nanoparticle functionalization methods to address these challenges by using trehalose, a naturally occurring disaccharide that offers exceptional protein stabilization. Plasmon‐enhanced Raman spectroscopy and far‐red fluorescence emission of the plasmonic silver nanoparticulate clusters are harnessed to create a unique dual‐functional, aggregating, and imaging agent that obviates the need of an additional reporter to investigate mucus–nanoparticle interactions. These spectroscopy‐based density mapping tools uncover the mechanism of mucus–nanoparticle interactions and establish the protective role of trehalose microenvironment in minimizing the nanoparticle aggregation. Thus, in contrast to the prevailing belief, these results demonstrate that nonfunctionalized nanoparticles may rapidly penetrate through mucus barriers, and by leveraging the bioprotectant attributes of trehalose, an in vivo milieu for efficient mucosal drug delivery can be generated.     

Comparative Permeability of Some Acyclovir Derivatives Through Native Mucus and Crude Mucin Dispersions

The permeability of some guanine derivatives (acyclovir [ACV], deoxyacyclovir [DCV], and their N-acetyl congeners) through native porcine mucus and crude porcine mucin dispersions (30% and 50% w/v) was investigated in two-compartment dialysis cells. High correlation between apparent permeability coefficients P_app of tested substances determined in these two models was observed, although the examined compounds permeated faster through the native mucus. It was also established that P_app values decrease with increasing hydrophilicity and molecular mass of the tested substances. Furthermore, the influence of some substances that affect mucus structure (cysteine, N-acetylcysteine [NCY], sodium taurocholate [ST], and sodium chloride) on the permeation rate of the examined compounds through mucus and mucin dispersions was examined. It was shown that the P_app values of guanine derivatives were generally lower after the addition of these substances to the native mucus and mucin dispersions, although the lowering effect was more pronounced in the case of native mucus.     

Ultrastructure of Tracheal Surface Liquid: Low-Temperature Scanning Electron Microscopy

A layer of liquid lines the airways in the lung. Previous microscopic studies have suggested that it is in two phases, with a mucous gel lying above a periciliary sol. However, shrinkage artifacts due to chemical fixation, dehydration, and drying have prevented reliable estimates of the depth of these layers. To avoid such problems, we have studied the surface liquid of bovine trachea by low-temperature scanning electron microscopy (LTSEM). A polished copper probe cooled to liquid nitrogen temperature was applied to the mucosal surface of sheets of excised tracheal epithelium to effect rapid freezing of surface liquid. Tissue sheets were then mounted in an LTSEM (AMRay 1000A with Biochamber) which maintains samples at -180°C with a Joule-Thompson refrigerator built into the stage. Tissues were fractured at right angles to the epithelial surface, coated with gold, and viewed, all at 10^?5 to 10^?6 torr without transfer through air. The sample was stable under the electron beam at accelerating voltages up to 20 kV. Epithelial features (nuclei, cilia, microvilli, mucous granules) were well preserved. The mucosal surface of the cells was covered with material on the order of 8 μm in depth. The mucous gel and periciliary sol could be seen as distinct layers and could be distinguished by the size and pattern of ice crystal voids generated by radiant-etching of the fractured surface of the sample.     

合浦珠母贝黏液细菌F35的鉴定及其抗菌物质分析

利用Zobell 2216E培养基从合浦珠母贝黏液中分离得到菌株F35,菌株对6种常见的食源性致病菌均有抑制作用。通过对菌株F35细菌形态观察、生理生化特性并结合16S rRNA基因序列分析,鉴定该菌为甲基营养型芽孢杆菌(Bacillus methylotrophicus)。其发酵液排除酸类物质和过氧化氢的干扰后,分别经过4种蛋白酶处理,蛋白酶酶解发酵液对指示菌的抑制作用均有不同程度的下降,表明菌株F35抗菌成分为蛋白或多肽类物质,具有开发为新型天然食品防腐剂的潜力。     

Tannic acid inhibition of amino acid and sugar absorption by mouse and vole intestine: Tests following acute and subchronic exposure

The acute effects of tannin (tannic acid; TA) on nutrient absorption were studied by measuring sugar and amino acid uptake across the brash border (luminal membrane) of intact intestine in the presence and absence of TA. Incubation of tissue for 4–9 min in TA solution (1 mg/ml) caused a reduction in passive influx ofl-glucose in voles and mice and a reduction in carrier-mediated influx ofd-glucose and total influx ofl-proline in mice, but not voles. In subchronic experiments, mice and voles were fed for 7–14 days a diet with 4% TA, but there was no significant effect on intestinal brush border uptake ofl-glucose,d-glucose, orl-proline (or three other amino acids tested in voles). In a synthesis of our study with others in the literature, three inferences are made from the patterns of effects across solutes, time scales of exposure, and species. First, the transport inhibitory effects following acute exposure are probably mediated by two processes: increased resistance to passive flux across an effective unstirred layer juxtaposed to the brush border membrane, perhaps due to tannin-mucin binding, and reduced Na⁺-coupled nutrient uptake across the intestinal brush border. Second, there is a species sensitivity difference in TA's effect on the second process. Third, the negative effects observed at the acute time scale in vitro do not necessarily occur in animals eating TA subchronically because little TA reaches the luminal membrane, or if it does its effects are quickly reversed when the tissue is removed and washed with solution free of TA.