Isolation and characterization of a novel glycogen synthase kinase-3 gene, <Emphasis Type="Italic">GmGSK</Emphasis>, in <Emphasis Type="Italic">Glycine max</Emphasis> L. that enhances abiotic stress tolerance in <Emphasis Type="Italic">Saccharomyces cerevisiae</Emphasis>

A novel glycogen synthase kinase-3 gene, GmGSK, was isolated from Glycine max. It is 1,596 bp in length with one ORF of 410 amino acids. Southern blot analysis revealed that it has at least two copies in the G. max genome. GmGSK, when transiently expressed in Nicotiana tabacum leaves, was localized in both cell membrane and cytoplasm. Northern blot analysis indicated that GmGSK is expressed in all tissues, with highest expression in the root. GmGSK can be induced by various abiotic stresses. When transformed with GmGSK, Saccharomyces cerevisiae exhibited enhanced resistance to salt and drought stress.     

A model on liquid penetration into soft material with application to needle-free jet injection

A mathematical model has been presented for a high speed liquid jet penetration into soft solid by a needle-free injection system. The model consists of a cylindrical column formed by the initial jet penetration and an expansion sphere due to continuous deposition of the liquid. By solving the equations of energy conservation and volume conservation, the penetration depth and the radius of the expansion sphere can be predicted. As an example, the calculation results were presented for a typical needle-free injection system into which a silicon rubber was injected into. The calculation results were compared with the experimental results.     

Structures of the Michaelis complex (1.2 Å) and the covalent acyl intermediate (2.0 Å) of cefamandole bound in the active sites of the Mycobacterium tuberculosis β-lactamase K73A and E166A mutants

The genome of Mycobacterium tuberculosis (TB) contains a gene that encodes a highly active β-lactamase, BlaC, that imparts TB with resistance to β-lactam chemotherapy. The structure of covalent BlaC-β-lactam complexes suggests that active site residues K73 and E166 are essential for acylation and deacylation, respectively. We have prepared the K73A and E166A mutant forms of BlaC and have determined the structures of the Michaelis complex of cefamandole and the covalently bound acyl intermediate of cefamandole at resolutions of 1.2 and 2.0 ?, respectively. These structures provide insight into the details of the catalytic mechanism.     

Assessing age,breeding stage,and mating activity as drivers of variation in the reproductive microbiome of female tree swallows

Sexually transmitted microbes are hypothesized to influence the evolution of reproductive strategies. Though frequently discussed in this context, our understanding of the reproductive microbiome is quite nascent. Indeed, testing this hypothesis first requires establishing a baseline understanding of the temporal dynamics of the reproductive microbiome and of how individual variation in reproductive behavior and age influence the assembly and maintenance of the reproductive microbiome as a whole. Here, we ask how mating activity, breeding stage, and age influence the reproductive microbiome. We use observational and experimental approaches to explain variation in the cloacal microbiome of free‐living, female tree swallows (Tachycineta bicolor). Using microsatellite‐based parentage analyses, we determined the number of sires per brood (a proxy for female mating activity). We experimentally increased female sexual activity by administering exogenous 17ß‐estradiol. Lastly, we used bacterial 16S rRNA amplicon sequencing to characterize the cloacal microbiome. Neither the number of sires per brood nor the increased sexual activity of females significantly influenced female cloacal microbiome richness or community structure. Female age, however, was positively correlated with cloacal microbiome richness and influenced overall community structure. A hypothesis to explain these patterns is that the effect of sexual activity and the number of mates on variation in the cloacal microbiome manifests over an individual''s lifetime. Additionally, we found that cloacal microbiome alpha diversity (Shannon Index, Faith''s phylogenetic distance) decreased and community structure shifted between breeding stages. This is one of few studies to document within‐individual changes and age‐related differences in the cloacal microbiome across successive breeding stages. More broadly, our results contribute to our understanding of the role that host life history and behavior play in shaping the cloacal microbiomes of wild birds.     

Instability of, and generation of hydrogen peroxide by, phenolic compounds in cell culture media

Many papers in the literature have described complex effects of flavonoids and other polyphenols on cells in culture. In this paper we show that hydroxytyrosol, delphinidin chloride and rosmarinic acid are unstable in three commonly-used cell culture media (Dulbecco’s modified Eagle’s medium (DMEM), RPMI 1640 (RPMI) and Minimal Essential Medium Eagle (MEM)) and undergo rapid oxidation to generate H₂O₂. This may have confounded some previous studies on the cellular effects of these compounds. By contrast, apigenin, curcumin, hesperetin, naringenin, resveratrol and tyrosol did not generate significant H₂O₂ levels in these media. Nevertheless, curcumin and, to a lesser extent, resveratrol (but not tyrosol) were also unstable in DMEM, so the absence of detectable H₂O₂ production by a compound in cell culture media should not be equated to stability of that compound. Compound instability and generation of H₂O₂ must be taken into account in interpreting effects of phenolic compounds on cells in culture.     

雌性大鼠结膜、睑板腺组织中肥大细胞的分布及形态学研究

目的:研究雌性大鼠结膜、睑板腺组织中肥大细胞的形态及分布.方法:用HE染色和改良甲苯胺蓝染色方法.结果:肥大细胞在穹隆结膜和睑结膜的固有层均有分布,细胞形态多样,大小不等,以圆形、卵圆形为多见,尚可见少量梭形、锥形;穹隆结膜的肥大细胞数量较睑结膜多.睑板腺组织中肥大细胞分布在被膜和相邻腺泡间质内,被膜内的肥大细胞以梭形、卵圆形为主,细胞长轴沿被膜平行排列;相邻腺泡间质中的肥大细胞以圆形、卵圆形或不规则形为主.可见少数相邻肥大细胞借胞体的突起互相连结.结论:为进一步探讨肥大细胞在结膜、睑板腺组织中的生物学作用以及眼表疾病的发生机制奠定了基础.     

穿心莲内酯抑制人结肠癌SW1116细胞增殖及诱导细胞凋亡作用的研究

目的:观察穿心莲内酯对人结肠癌SW1116细胞生长及肿瘤细胞凋亡的影响,探讨其可能的机制.方法:用不同浓度的穿心莲内酯处理SW1116细胞,MTT检测穿心莲内酯对SW1116细胞生长增殖的抑制作用;流式细胞术(FCM)检测细胞凋亡率;比色法测定Caspase-3酶活性;Western blot法检测bax、Bcl-2的蛋白表达.结果:穿心莲内酯能够剂量依赖型的抑制人结肠癌SW1116细胞的增殖,并诱导凋亡;穿心莲内酯与SW1116细胞作用48小时后Caspase-3酶活性显著增强;同时,穿心莲内酯处理SW1116细胞后,Bax蛋白表达增强,Bcl-2蛋白表达下调.结论:穿心莲内酯可抑制人结肠癌SW1116的增殖,诱导其凋亡,机制可能与调节Caspase-3、Bcl-2和Bax表达水平有关.     

The Notch signaling pathway in retinal dysplasia and retina vascular homeostasis

The retina is one of the most essential elements of vision pathway in vertebrate. The dysplasia of retina cause congenital blindness or vision disability in individuals, and the misbalance in adult retinal vascular homeostasis leads to neovaseularization-associated diseases in adults, such as diabetic retinopathy or age-related macular degeneration. Many developmental signaling pathways are involved in the process of retinal development and vascular homeostasis. Among them, Notch signaling pathway has long been studied, and Notch signaling-interfered mouse models show both neural retina dysplasia and vascular abnormality. In this review, we discuss the roles of Notch signaling in the maintenance of retinal progenitor cells, specification of retinal neurons and glial cells, and the sustaining of retina vascular homeostasis, especially from the aspects of conditional knockout mouse models. The potential of Notch signal mampulation may provide a powerful cell fate- and neovascularization-controlling tool that could have important applications in la'eatment of retinal diseases.