新疆酸白菜发酵的研究

通过对低温自然发酵中的酸白菜进行定期取样,分析了乳酸菌、大肠杆菌、酵母菌及细菌总数的变化,同时测定发酵过程中酸白菜酸度和脆度指标.结果表明,发酵初期人肠杆菌和杂菌为优势菌群,酸度为0.31%,脆度为10.06mJ;发酵中期乳酸菌成为优势菌群,其次为酵母菌,酸度为0.66%,脆度为15.01mJ;发酵末期大肠杆菌被抑制,乳酸菌和酵母菌减少,但乳酸菌仍然是优势菌群,酸度为1.27%,脆度为36.47mJ.酸度0.66%及脆度15.01mJ时,酸白菜口感风味最佳.     

Biotransformation of phlorizin by human intestinal flora and inhibition of biotransformation products on tyrosinase activity

Phlorizin (1) was anaerobically incubated with human intestinal bacteria and five biotransformation products (2-6) were obtained. Their structures were elucidated as phloretin (2), phloroglucinol (3), phloretic acid (4), 2,3,4-trihydroxybenzenepropanoic acid (5), and phloretic acid methyl ester (6) on the basis of their spectroscopic data. Using high-performance liquid chromatography equipped with a diode array detector, chromatographic separation of 1-4 was performed on an analytical C₁₈ column. The time course of the biotransformation was studied to probe into the biotransformation mechanism of 1 by human intestinal flora. The abilities of isolated strains to transform 1 were also investigated in order to find an optimal transformation strain. In addition, the inhibitory activity of parent compound 1 and its three main biotransformation products 2-4 on mushroom tyrosinase was estimated. The result showed that 2 has better inhibitory effect on tyrosinase activity than 1.     

Eosinophils and Bacteria,the Beginning of a Story

Eosinophils are granulocytes primarily associated with T_H2 responses to parasites or immune hyper-reactive states, such as asthma, allergies, or eosinophilic esophagitis. However, it does not make sense from an evolutionary standpoint to maintain a cell type that is only specific for parasitic infections and that otherwise is somehow harmful to the host. In recent years, there has been a shift in the perception of these cells. Eosinophils have recently been recognized as regulators of immune homeostasis and suppressors of over-reactive pro-inflammatory responses by secreting specific molecules that dampen the immune response. Their role during parasitic infections has been well investigated, and their versatility during immune responses to helminths includes antigen presentation as well as modulation of T cell responses. Although it is known that eosinophils can present antigens during viral infections, there are still many mechanistic aspects of the involvement of eosinophils during viral infections that remain to be elucidated. However, are eosinophils able to respond to bacterial infections? Recent literature indicates that Helicobacter pylori triggers T_H2 responses mediated by eosinophils; this promotes anti-inflammatory responses that might be involved in the long-term persistent infection caused by this pathogen. Apparently and on the contrary, in the respiratory tract, eosinophils promote T_H17 pro-inflammatory responses during Bordetella bronchiseptica infection, and they are, in fact, critical for early clearance of bacteria from the respiratory tract. However, eosinophils are also intertwined with microbiota, and up to now, it is not clear if microbiota regulates eosinophils or vice versa, or how this connection influences immune responses. In this review, we highlight the current knowledge of eosinophils as regulators of pro and anti-inflammatory responses in the context of both infection and naïve conditions. We propose questions and future directions that might open novel research avenues in the future.     

乳制品对骨质疏松症的预防和干预作用研究进展

骨质疏松症困扰着全球2亿患者,随着全球人口老龄化的加剧,骨质疏松发病率将不断增加,预防骨质疏松成为公共卫生领域亟待解决的问题。本文分析了乳制品基质、矿物质、维生素、乳蛋白、乳脂和乳糖调节肠道菌群对钙吸收和骨骼健康的作用机制,综述了强化添加VD、益生元和益生菌的乳制品对不同人群的干预效果及降低骨质疏松风险的研究进展,比较了乳制品与植物基替代品的干预功效,为乳制品精准干预改善骨骼健康提供科学参考。     

Natural flavonoids are potent inhibitors of glycogen phosphorylase

There is little known about effects to be expected from high intake of flavonoids with respect to regulation of glucose/glycogen homeostasis. Glucose/glycogen homeostasis is mainly regulated by glycogen synthase (GS) and glycogen phosphorylase (GP). We investigated effects of naturally occurring flavonoids with varying substitution pattern on the activity of isolated muscle GP. Almost all flavonoids tested inhibited phosphorylated, active GPa, as well as unphosphorylated, adenosine monophosphate-activated GPb. However, inhibition of GPa was two-to-fourfold stronger than that of GPb. The flavonol quercetin and the anthocyanidins cyanidin and delphinidin turned out to be the most potent inhibitors of GPa, with concentration values where enzymatic activity is 50% of the respective control in the low micromolar range (<5 microM). Furthermore, by comparing GPa inhibitory activity of typical representatives from all known flavonoid classes, structural elements of flavonoids required for effective GP inhibition could be identified.     

PCRDGGE技术分析混菌发酵乳中马克斯克鲁维酵母与乳酸菌的相互作用

利用变性梯度凝胶电泳(Denaturing Gradient Gel Electrophoresis,DGGE)技术,对混菌发酵及贮藏过程中马克斯克鲁维酵母与乳酸菌之间的相互作用进行分析,进而对整个过程中微生物优势菌群及其稳定性进行跟踪监测。结果表明:混菌发酵及贮藏过程中微生物组成比较稳定,优势菌为嗜热链球菌(Streptococcus thermophilus,ST);发酵过程中,马克斯克鲁维酵母(Kluyveromyces marxianus)的添加对乳酸菌生长起到促进作用,尤其是对保加利亚乳杆菌(Lactobacillus bulgaricus,LB)效果显著,贮藏期间该作用转变为抑制;整个过程乳酸菌的存在对酵母菌的生长具有一定的抑制作用。该研究可为深入探讨乳酸菌与酵母菌共同发酵机理及新型发酵乳制品的开发提供理论基础。     

When Phosphatases Go Mad: The Molecular Basis for Toxicity of Yeast Ppz1

The fact that overexpression of the yeast Ser/Thr protein phosphatase Ppz1 induces a dramatic halt in cell proliferation was known long ago, but only work in the last few years has provided insight into the molecular basis for this toxicity. Overexpression of Ppz1 causes abundant changes in gene expression and modifies the phosphorylation state of more than 150 proteins, including key signaling protein kinases such as Hog1 or Snf1. Diverse cellular processes are altered: halt in translation, failure to properly adapt to low glucose supply, acidification of the cytosol, or depletion of intracellular potassium content are a few examples. Therefore, the toxicity derived from an excess of Ppz1 appears to be multifactorial, the characteristic cell growth blockage thus arising from the combination of various altered processes. Notably, overexpression of the Ppz1 regulatory subunit Hal3 fully counteracts the toxic effects of the phosphatase, and this process involves intracellular relocation of the phosphatase to internal membranes.     

Iron Homeostasis in the CNS: An Overview of the Pathological Consequences of Iron Metabolism Disruption

Iron homeostasis disruption has increasingly been implicated in various neurological disorders. In this review, we present an overview of our current understanding of iron metabolism in the central nervous system. We examine the consequences of both iron accumulation and deficiency in various disease contexts including neurodegenerative, neurodevelopmental, and neuropsychological disorders. The history of animal models of iron metabolism misregulation is also discussed followed by a comparison of three patients with a newly discovered neurodegenerative disorder caused by mutations in iron regulatory protein 2.     

Synergistic Activity of Ketoconazole and Miconazole with Prochloraz in Inducing Oxidative Stress,GSH Depletion,Mitochondrial Dysfunction,and Apoptosis in Mouse Sertoli TM4 Cells

Triazole and imidazole fungicides represent an emerging class of pollutants with endocrine-disrupting properties. Concerning mammalian reproduction, a possible causative role of antifungal compounds in inducing toxicity has been reported, although currently, there is little evidence about potential cooperative toxic effects. Toxicant-induced oxidative stress (OS) may be an important mechanism potentially involved in male reproductive dysfunction. Thus, to clarify the molecular mechanism underlying the effects of azoles on male reproduction, the individual and combined potential of fluconazole (FCZ), prochloraz (PCZ), miconazole (MCZ), and ketoconazole (KCZ) in triggering in vitro toxicity, redox status alterations, and OS in mouse TM4 Sertoli cells (SCs) was investigated. In the present study, we demonstrate that KCZ and MCZ, alone or in synergistic combination with PCZ, strongly impair SC functions, and this event is, at least in part, ascribed to OS. In particular, azoles-induced cytotoxicity is associated with growth inhibitory effects, G0/G1 cell cycle arrest, mitochondrial dysfunction, reactive oxygen species (ROS) generation, imbalance of the superoxide dismutase (SOD) specific activity, glutathione (GSH) depletion, and apoptosis. N-acetylcysteine (NAC) inhibits ROS accumulation and rescues SCs from azole-induced apoptosis. PCZ alone exhibits only cytostatic and pro-oxidant properties, while FCZ, either individually or in combination, shows no cytotoxic effects up to 320 µM.