Biosynthesis of the polysialic acid capsule inEscherichia coli K1

The extracellular polysaccharides elaborated by most or all bacterial species function in cell-to-cell and cell-substratum adhesion, cell signaling, and avoidance or inhibition of noxious agents in animal hosts or free-living environments. Recent advances in our understanding of exopolysaccharide synthesis have been facilitated by comparative approaches in both plant and animal pathogens, as well as in microorganisms of industrial importance. One of the best understood of these systems is thekps locus for polysialic acid synthesis inEscherichia coli K1. The genes for sialic acid synthesis, activation, polymerization and translocation have been identified and assigned at least tentative functions in the synthetic and export pathways. Initial studies ofkps thermoregulation suggest that genetic control mechanisms will be involved which are distinct from those already described for several other exopolysaccharides. Information about the common as well as unique features of polysialic acid biosynthesis will increase our knowledge of microbial cell surfaces which in turn may suggest novel targets for therapeutic or industrial interventions.     

The nature of the adhesion of Corynebacterium rathayi to the cuticle of the infective larva of Anguina agrostis

The relationship between Corynebacterium rathayi and the infective second stage ‘dauer” larva (DL₂) of Anguina agrostis has been studied with particular regard to the nature and extent of bacterial adhesion to the nematode. Viability of the 1-year-old DL₂ was high, the number of dead specimens per gall only ranging from 5.1% to 8.3%. The DL₂ were exposed to C. rathayi either from cultures or galls and the numbers with and without adhering bacteria were counted. A total of 22,917 DL₂ from 15 galls were examined, the mean number of DL₂ per gall being 1,528. The mean percentage per gall of DL₂ with bacteria adhering was 42%. However there was much variability (from 0 to 98%). The significance of galls with DL₂ that did not succumb to bacterial adhesion is discussed. The sequence of events associated with the process of bacterial adhesion to the nematode cuticle was examined with the aid of the electron microscope. The process involves fusion of the glycocalyx with the bacterial capsule followed by thickening and, at times, displacement of the epicuticle together with changes in the main body of the cuticle. The possible nature of the process of adhesion is discussed.     

Quantification of liver fibrosis via second harmonic imaging of the Glisson's capsule from liver surface

Liver surface is covered by a collagenous layer called the Glisson's capsule. The structure of the Glisson's capsule is barely seen in the biopsy samples for histology assessment, thus the changes of the collagen network from the Glisson's capsule during the liver disease progression are not well studied. In this report, we investigated whether non‐linear optical imaging of the Glisson's capsule at liver surface would yield sufficient information to allow quantitative staging of liver fibrosis. In contrast to conventional tissue sections whereby tissues are cut perpendicular to the liver surface and interior information from the liver biopsy samples were used, we have established a capsule index based on significant parameters extracted from the second harmonic generation (SHG) microscopy images of capsule collagen from anterior surface of rat livers. Thioacetamide (TAA) induced liver fibrosis animal models was used in this study. The capsule index is capable of differentiating different fibrosis stages, with area under receiver operating characteristics curve (AUC) up to 0.91, making it possible to quantitatively stage liver fibrosis via liver surface imaging potentially with endomicroscopy.

     

胰岛素联合百令胶囊治疗早期糖尿病肾病患者的临床疗效

目的:观察胰岛素联合百令胶囊治疗早期糖尿病肾病患者的临床疗效,并探讨其可能机制。方法:收集在我院就诊或住院治疗的62例糖尿名肾病患者,随机分为实验组和对照组,每组31例。对照组患者给予诺和灵30R胰岛素,实验组患者在对照组基础上给予百令胶囊治疗。治疗后,对患者的血肌酐、尿蛋白、CD68以及临床疗效进行检测并比较。结果:与治疗前相比,两组患者治疗后的血肌酐、尿蛋白、CD68均下降(P0.05);与对照组相比,实验组患者的血肌酐、尿蛋白、CD68水平较低(P0.05),临床治疗有效率较高(P0.05)。结论:胰岛素联合百令胶囊能够有效提高早期糖尿病肾病患者的临床疗效,可能与其降低血清CD68水平,减轻炎症反应有关。     

缬沙坦联合通心络胶囊对糖尿病心肌病患者血清肌钙蛋白及SOD水平的影响

目的:探讨缬沙坦联合通心络胶囊对糖尿病心肌病患者血清肌钙蛋白,SOD及生活质量的影响。方法:收集我院就诊或住院治疗的60例糖尿病心肌病患者,随机分为实验组和对照组,每组30例。对照组患者给予缬沙坦口服治疗,实验组患者在此基础上给予通心络治疗。检测并比较两组患者治疗前后血清cTnI、生活质量、SOD、运动耐量的变化情况。结果:与治疗前相比,两组患者治疗后血清cTnI和生活质量评分均下降,而SOD和运动耐量水平均升高,差异具有统计学意义(P0.05);与对照组相比,实验组患者治疗后血清cTnI和生活质量评分较低,而SOD和运动耐量水平较高,差异具有统计学意义(P0.05)。结论:缬沙坦联合通心络胶囊能够降低糖尿病心肌病患者cTnI、生活质量评分,升高其SOD以及运动耐量水平,对临床具有指导意义。     

多烯磷脂酰胆碱胶囊联合复方益肝灵胶囊治疗抗结核药物致肝损伤患者的临床疗效

目的:研究多烯磷脂酰胆碱胶囊联合复方益肝灵胶囊治疗抗结核药物致肝损伤患者的临床疗效。方法:选取2014年4月到2015年4月我院收治的抗结核药物致肝损伤患者150例,按照随机数字表法将患者分为研究组和对照组,每组75例,两组均继续行抗结核治疗,对照组给予常规保肝药物治疗,研究组给予多烯磷脂酰胆碱胶囊联合复方益肝灵胶囊保肝治疗,比较两组临床疗效,治疗前后谷丙转氨酶(ALT)、谷草转氨酶(AST)以及r-谷氨酰转移酶(r-GT)。结果:研究组有效率为89.3%显著高于对照组的73.3%,两组比较差异具有统计学意义(P0.05);两组治疗后AST、ALT以及r-GT显著低于治疗前,且治疗后研究组AST、ALT以及r-GT均显著低于对照组,比较差异均具有统计学意义(均P0.05)。结论:多烯磷脂酰胆碱胶囊联合复方益肝灵胶囊治疗抗结核药物致肝损伤具有较好临床疗效,能增强对肝脏的保护作用。     

The influence of ectomycorrhiza on nitrogen nutrition and growth of Pinus sylvestris seedlings

Ectomycorrhizal seedlings of Scots pine ( Pinus sylvestris L. cv.), inoculated with the fungus Suillus bovinus (L. ex Fr.) O. Kuntze, and non-mycorrhizal controls were grown in growth units with a circulating culture solution. Steady-state nutrition and constant relative growth rates were achieved by means of varied relative nutrient addition rates and free access of nutrients. Typical mycorrhizas always formed within a short period of time after inoculation. The nutrition/growth relationships were in principle similar to previous studies under steady-state conditions: there were close linear relationships between relative addition rate, relative growth rate and internal nitrogen concentration, i.e. an equilibrium established between nutrients added and taken up. This occurred when infected and uninfected seedlings were grown separately. When grown together in the same growth unit, there are indications that the fungus influenced the exudation pattern of the uninfected seedlings. More carbon was thus provided to the unspecified microflora in the cultivation system, and it was able to grow and withhold nitrogen from the seedlings. The mycorrhizal infection did not increase the specific uptake capacity of the roots, and the fungus constituted a sink for carbon. However, the nitrogen productivity (growth rate per unit of nitrogen per unit of time) was similar for mycorrhizal and non-mycorrhizal seedlings, so that there might be mechanisms which compensate for the carbon cost.     

Short and long range order in basement membrane type IV collagen revealed by enzymic and chemical extraction

Oriented bovine lens capsules give X-ray diffraction patterns suggesting a considerable degree of order in the collagenous components, predominantly type IV collagen. Here we report the effects of preliminary treatment of lens capsules before orientation. Extraction with 4 guanidinium hydrochloride or with heparinase/hyaluronidase reveals the same collagenous diffraction patterns previously seen after extraction with 1 NaCl. There is a four-point pattern of d-spacing 3.9 nm, indicating liquid crystal cybotactic nematic organization, along with sharp streaked meridional reflections which index as orders of 21 nm. This suggests that the removal of basement membrane proteoglycans results in a reduction in diffuse scatter and clarification of the pattern. Extraction of the lens capsules with trypsin or dithiothreitol greatly reduces the intensity of the four-point pattern while leaving the meridional pattern unaffected. This strengthens the evidence that the 21 nm period has its origins in the collagen IV helix. Reduction in the four-point pattern could arise if disruption of non-helical NC1 domains or 7S overlap regions allows slippage of the collagen molecules on orientation, weakening the proposed 1 nm intermolecular stagger. Ultra-low angle diffraction patterns of extracted lens capsules show meridional reflections which index as a long-range axial repeat of approximately 95 nm. This is consistent with a model of microfibrils of type IV collagen in which the NC1 domains bind to the collagen helix at approximately 100 nm intervals, as has been previously suggested.     

Seed weight and seed number affect subsequent fitness in outcrossing and selfing Primula species

Using the outcrossing Primula farinosa and its autogamous selfing relatives P. scotica , P. scandinavica and P. stricta , we compared the fitness of light and heavy seeds. Heavy seeds germinated in greater numbers and more quickly. In competition with seedlings grown from lighter seeds, heavy seeds produced larger rosettes. In P. farinosa such seedlings went on to produce more seeds, and in two populations heavier seeds, than plants from lighter seeds. After transplantation to natural populations, seedlings of P. farinosa derived from heavy seeds produced larger rosettes, more flowers and seeds than those from lighter seeds in certain populations so that seedlings born of heavy seeds were much fitter than seedlings from lighter seeds. Average seed weight varied in inverse proportion to seed number per capsule. The autogamous species produced on average about twice as many seeds per capsule as P. farinosa . In P. scotica and P. stricta this difference appears to be due in part to assured fertilization, but this high fecundity did not cause disadvantageously light seeds. As these species produced fewer capsules per scape, their overall seed production was on average no greater than for P. farinosa . P. farinosa traded-off fitness between capsules with large seed numbers, which donated more offspring to the next generation, and those with small seed numbers, whose heavy seeds would be more likely to reproduce themselves in the next generation. We conclude that low fecundity in outcrossing species might at times be advantageous.