Simultaneous quantification of nucleoproteins and comparison of methyl green-pyronin Y and Feulgen staining in sections of oral squamous cell carcinoma,dysplastic lesions and normal mucosa

A fundamental difference between normal cells and tumor cells is the proliferative activity of the nucleus and nucleolus, which increases progressively from normal to oral dysplastic mucosa to oral squamous cell carcinoma (OSCC). This activity is evaluated routinely using hematoxylin and eosin (H & E) staining, but in some cases, inter-observer variability occurs among pathologists. We evaluated cellular proliferation by staining sections with the methyl green-pyronin Y procedure and the Feulgen reaction. We also compared the efficacy of methyl green-pyronin Y and Feulgen staining for studying nuclear and nucleolar features in oral dysplastic mucosa and in different grades of OSCC. Sections cut from formalin fixed, paraffin embedded blocks of five normal mucosa, 15 dysplastic mucosa, 10 well-differentiated OSCC, 10 moderately differentiated OSCC and five poorly differentiated OSCC cases were stained with Hematoxylin and Eosin, methyl green-pyronin Y and the Feulgen reaction. The mean diameters of the nuclei and number of nucleoli showed significant differences. A progressive increase in diameter of the nucleus and number of nucleoli was observed from normal mucosa through poorly differentiated OSCC. We observed that methyl green-pyronin Y stain is more useful than Feulgen and hematoxylin and eosin for simultaneous quantitative assessment of both RNA and DNA. The simplicity of this technique makes it a valuable tool even for daily routine examination.     

Molecular distribution of zinc in biliary and pancreatic secretions

Rat bile and pancreatic fluid were examined for the presence of low molecular weight zinc complexes. Fluids were collected separately by cannulation, and zinc distribution in collected samples was analyzed by gel filtration on Sephadex G-50. Most of the zinc in bile was associated with low molecular weight zinc complexes; only a small amount of zinc was present in the high molecular weight fraction. In contrast, pancreatic secretions did not contain low molecular weight zinc complexes, but there were considerable amounts of zinc bound to high molecular weight compounds. The addition of zinc to bile resulted in an increased amount of zinc in the low molecular weight fraction, while the addition of zinc to pancreatic fluid resulted primarily in an increase in zinc bound to the high molecular weight components. Like pancreatic fluid, homogenates of pancreatic tissue had no low molecular weight zinc complex. In rats whose bile and pancreatic fluid were removed and not returned into the intestine, the amount of zinc bound to low molecular weight complexes in intestinal homogenates was reduced. This alteration of the molecular distribution of zinc in intestinal homogenates by removal of bile and pancreatic fluid suggests the potential importance of low molecular weight zinc complexes for zinc homeostasis.     

鸡肠道微生物演替与早期定植的研究进展

鸡肠道中寄生着数量庞大且复杂多样的微生物,对宿主的生长发育和健康十分重要,既影响着饲料消化、营养物质吸收,又参与了宿主肠道形态和免疫系统的调控。深入了解鸡肠道微生物区系的时空变化及早期定植特点,将有助于提出新的肠道微生态干预策略,应用于生产。就鸡肠道微生物组成和演替、早期微生物区系建立及调控等方面进行综述,并总结了一些最新研究进展。     

大鼠实验性脾虚证胃粘膜内分泌细胞变化的免疫组织化学研究

用正常成年雄性Wistar大鼠53只,体重100～150g,分为正常对照组、实验性脾虚组、自然恢复组和四君子汤治疗组。取胃,固定于Bouin液。制成石蜡切片,进行(1)HE染色;(2)免疫组织化学染色,按Sternberger PAP法显示胃泌素细胞(G细胞)、生长抑素细胞(D细胞)和5-HT细胞。根据细胞的免疫反应程度,将细胞分为强阳性、中等阳性和弱阳性三级,每例动物计数三种细胞各1,000个,并计算各级细胞占的百分比;(3)从正常对照组,脾虚组随机选择各5例动物,对D细胞和G细胞进行显微分光光度计的定量测定;(4)由四组动物随机选择各5例,进行G细胞和D细胞密度及G/D细胞比值的测定。本文的观察表明:(1)脾虚组胃粘膜未见明显的组织学变化;(2)内分泌细胞:与对照组相比,脾虚组G细胞和5-HT细胞中,弱阳性细胞增多,表明分泌活动增强;D细胞弱阳性和中等阳性细胞减少,强阳性细胞增多,表明分泌释放减弱,合成增强。与自然恢复组比较,治疗组G细胞和D细胞的分泌活动接近于对照组;5-HT细胞无明显的恢复;(3)显微分光光度计的测定结果与光镜观察一致,脾虚组G细胞胃泌素反应物的含量低于对照组,D细胞内生长抑素反应物的含量高于对照组;(4)脾虚组G细胞密度低于对照组(P<0.01),D细胞密度略高于对照组,G/D细胞比值也低于对照组(P<0.01)。本文结果提示,脾虚证这些内分泌细胞的分泌活动出现异常,可能是导致消化功能紊乱的原因之一。经四君子汤治疗后,内分泌细胞的分泌活动接近于对照组,说明此药对脾虚证有一定的治疗作用。     

In Vivo Analysis of Centromeric Proteins Reveals a Stem Cell-Specific Asymmetry and an Essential Role in Differentiated,Non-proliferating Cells

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肠道噬菌体组生物信息学分析方法的研究进展

噬菌体是感染细菌的病毒,广泛存在于各类环境中。由于传统实验研究的局限性及噬菌体基因的特异性,导致对肠道噬菌体的研究很少。随着宏基因组测序技术的发展和各种生物信息分析软件的开发,可以通过噬菌体组学,加深对肠道噬菌体的认识。噬菌体组分析流程主要包括原始数据质量控制和预处理,病毒基因组序列的拼接组装,类病毒颗粒的筛选和系统分类注释以及进化分析和预测相应宿主细菌。本文对噬菌体组分析流程和其中所需要的常用生物信息分析工具和数据库进行详细的介绍,可以为肠道噬菌体研究以及相关的研究人员提供参考。     

Mapping early fate determination in Lgr5+ crypt stem cells using a novel Ki67‐RFP allele

Cycling Lgr5⁺ stem cells fuel the rapid turnover of the adult intestinal epithelium. The existence of quiescent Lgr5⁺ cells has been reported, while an alternative quiescent stem cell population is believed to reside at crypt position +4. Here, we generated a novel Ki67^RFP knock-in allele that identifies dividing cells. Using Lgr5-GFP;Ki67^RFP mice, we isolated crypt stem and progenitor cells with distinct Wnt signaling levels and cell cycle features and generated their molecular signature using microarrays. Stem cell potential of these populations was further characterized using the intestinal organoid culture. We found that Lgr5^high stem cells are continuously in cell cycle, while a fraction of Lgr5^low progenitors that reside predominantly at +4 position exit the cell cycle. Unlike fast dividing CBCs, Lgr5^low Ki67⁻ cells have lost their ability to initiate organoid cultures, are enriched in secretory differentiation factors, and resemble the Dll1 secretory precursors and the label-retaining cells of Winton and colleagues. Our findings support the cycling stem cell hypothesis and highlight the cell cycle heterogeneity of early progenitors during lineage commitment.     

New in vitro colonic fermentation model for Salmonella infection in the child gut

In this study, a new in vitro continuous colonic fermentation model of Salmonella infection with immobilized child fecal microbiota and Salmonella serovar Typhimurium was developed for the proximal colon. This model was then used to test the effects of two amoxicillin concentrations (90 and 180 mg day⁻¹) on the microbial composition and metabolism of the gut microbiota and on Salmonella serovar Typhimurium during a 43-day fermentation. Addition of gel beads (2%, v/v) colonized with Salmonella serovar Typhimurium in the reactor resulted in a high and stable Salmonella concentration (log 7.5 cell number mL⁻¹) in effluent samples, and a concomitant increase of Enterobacteriaeceae, Clostridium coccoides–Eubacterium rectale and Atopobium populations and a decrease of bifidobacteria. During amoxicillin treatments, Salmonella concentrations decreased while microbial balance and activity were modified in agreement with in vivo data, with a marked decrease in C. coccoides–E. rectale and an increase in Enterobacteriaceae . After interruption of antibiotic addition, Salmonella concentration again increased to reach values comparable to that measured before antibiotic treatments, showing that our model can be used to simulate Salmonella shedding in children as observed in vivo . This in vitro model could be a useful tool for developing and testing new antimicrobials against enteropathogens.     

谷氨酸钠摄入引起的果蝇肠道菌群多样性变化研究

谷氨酸钠(MSG),也称味精,是谷氨酸的钠盐,也是最丰富的天然存在的非必需氨基酸之一.MSG常作为一种增味剂被添加到食物中,但也有报道可引起哮喘、头痛甚至脑损伤.本文以黑腹果蝇作为材料,利用16S rDNA扩增子测序分析其肠道菌群对高MSG摄人的响应.结果发现饲喂MSG组果蝇相比对照组,其肠道的厚壁杆菌门 Firmic...