Effects of Growth Pressure and Temperature on Fatty Acid Composition of a Barotolerant Deep-Sea Bacterium

The effects of pressure and temperature on the fatty acid composition in a barotolerant deep-sea bacterium that had branched-chain fatty acids were examined. The major fatty acids of the strain at atmospheric pressure were iso-C_15:0, C_16:1, iso-C_17:0, and iso-C_17:1. As the growth pressure increased, the proportion of unsaturated fatty acid increased because of an increase in the proportion of iso-C_17:1. On the other hand, as the growth temperature decreased, the proportion of unsaturated fatty acid increased because of the increase in the proportion of C_16:1 and C_18:1.     

Dependence of Reproduction Rate on Pressure as a Hallmark of Deep-Sea Bacteria

Strains of bacteria in axenic culture were isolated from samples of depths between 1,957 and 10,476 m of the Pacific Ocean. All of the bacteria from this range of depths were barophilic. The pressure at which the rate of reproduction was maximal was found to be correlated with the depth of origin of the isolates.     

Positive Pressure Effect on Manganese Binding by Bacteria in Deep-Sea Hydrothermal Plumes

A positive pressure effect (1.4 to 3.3×) on the binding of Mn²⁺ by a natural population of bacteria in a deep-sea hydrothermal plume was discovered over the intermediate pressure range of 1 to 200 atm (1 to 200 bars; ca. 1.01 × 10² to 2.03 × 10⁴ kPa). The data suggest Mn²⁺ binding is functionally barophilic rather than simply barotolerant.     

不锈钢和氧化钛薄膜刺激内皮细胞释放NO和MCP-1的研究

目的:探讨不锈钢和氧化钛(Ti-O)薄膜对内皮细胞释放细胞因子的影响,评价生物材料表面的内皮细胞的功能.方法:用非平衡磁控溅射的方法制备Ti-O薄膜,提取人脐静脉内皮细胞(mrVEC)并种植到材料表面进行培养.第1、3、5天提取培养上清液,用NO检测试剂盒和酶联免疫吸附实验的方法进行一氧化氮(NO)和单核细胞趋化蛋白-1(Monocyte Chemotactic Protein 1,MCP-1)的检测,采用环境扫描电子显微镜(SEM)进行细胞形态观察.结果:内皮细胞在Ti-O薄膜表面上生长形态保持较好,其培养上清液NO和MCP-1因子释放量都要略小于不锈钢表面的.结论:Ti-O薄膜具有较好的促进内皮化和组织相容性,有望成为血管支架的新型生物材料.     

Cu 型医用抗菌不锈钢在大鼠体内抗细菌感染研究

目的:比较普通304医用不锈钢和304-Cu型医用抗菌不锈钢的体内抗细菌感染性能。方法:将两种不锈钢片涂布浓度为1×107cfu/mL的金黄色葡萄球菌培养24 h,植入SD大鼠胫腓骨肌袋内,继续饲养并在术前及术后第1、4、7、14天进行大体观察、植入部位细菌培养、白细胞计数、组织学观察等检测。结果:普通304不锈钢组术后中度化脓,检测到较多细菌,白细胞增多且有大量的炎症细胞出现;而304-Cu型抗菌不锈钢术后只有轻微化脓,检测到的细菌较少,白细胞数稍有增多但无统计学差异,炎症细胞少,感染程度轻。结论:与医用304不锈钢相比,304-Cu型抗菌不锈钢有较好的抗细菌性能,有一定的抗感染作用。     

Deep-Sea Bacteria: Growth and Utilization of Hydrocarbons at Ambient and In Situ Pressure

Microorganisms present in Atlantic Ocean sediment samples collected at a depth of 4,940 m were found to be capable of utilizing hydrocarbons under both ambient and in situ pressures. The rate of utilization under in situ pressure (500 atm) and ambient temperature (20 C) was found to be significantly less compared with hydrocarbon utilization examined under conditions of ambient temperature (20 C) and pressure (1 atm).     

The Injurious Effects of Hyperinsulinism on Blood Vessels

Insulin resistance (IR) is a common feature of hypertension, Type II diabetes, coronary heart disease, Syndrome X, and other vascular diseases. It refers to a state in which a certain concentration of insulin produces less biologic effect than expected in human body. When IR develops, the response of human body to insulin decreases accordingly, thus inducing the compensatory hyper-secretion of insulin and consequently hyperinsulinism. Many clinical and epidemiologic studies have demonstrated that IR and iatrogenic hyperinsulinism induced consequently play an essential role in the pathogenesis of hypertension and atherosclerotic cardiovascular diseases. Therefore, more and more attention should be paid to the mechanism of IR in order to explore more therapeutic basis and prospective for the treatment of atherosclerosis and other cardiovascular diseases. In this review, we provided a general overview on the known molecular mechanisms of IR and summarized the recent findings on the injurious effects of hyperinsulinism in vitro and in vivo, which might be important for researchers and clinicians to better understand the etiology and clinical significance of IR.     

Submarine Rescue Decompression Procedure from Hyperbaric Exposures up to 6 Bar of Absolute Pressure in Man: Effects on Bubble Formation and Pulmonary Function

Recent advances in submarine rescue systems have allowed a transfer under pressure of crew members being rescued from a disabled submarine. The choice of a safe decompression procedure for pressurised rescuees has been previously discussed, but no schedule has been validated when the internal submarine pressure is significantly increased i.e. exceeding 2.8 bar absolute pressure. This study tested a saturation decompression procedure from hyperbaric exposures up to 6 bar, the maximum operating pressure of the NATO submarine rescue system. The objective was to investigate the incidence of decompression sickness (DCS) and clinical and spirometric indices of pulmonary oxygen toxicity. Two groups were exposed to a Nitrogen-Oxygen atmosphere (pO₂ = 0.5 bar) at either 5 bar (N = 14) or 6 bar (N = 12) for 12 h followed by 56 h 40 min resp. 60 h of decompression. When chamber pressure reached 2.5 bar, the subjects breathed oxygen intermittently, otherwise compressed air. Repeated clinical examinations, ultrasound monitoring of venous gas embolism and spirometry were performed during decompression. During exposures to 5 bar, 3 subjects had minor subjective symptoms i.e. sensation of joint discomfort, regressing spontaneously, and after surfacing 2 subjects also experienced joint discomfort disappearing without treatment. Only 3 subjects had detectable intravascular bubbles during decompression (low grades). No bubbles were detected after surfacing. About 40% of subjects felt chest tightness when inspiring deeply during the initial phase of decompression. Precordial burning sensations were reported during oxygen periods. During decompression, vital capacity decreased by about 8% and forced expiratory flow rates decreased significantly. After surfacing, changes in the peripheral airways were still noticed; Lung Diffusion for carbon monoxide was slightly reduced by 1% while vital capacity was normalized. The procedure did not result in serious symptoms of DCS or pulmonary oxygen toxicity and may be considered for use when the internal submarine pressure is significantly increased.     

Influence of the Surface Topography of Stainless Steel on Bacterial Adhesion

Bacterial adhesion on stainless steel may cause problems such as microbially induced corrosion or represent a chronic source of microbial contamination. The investigation focussed on how the extent and patterns of four bacterial species comprising three different phyla and a broad variety of physicochemical characteristics was influenced by the surface topography of AISI 304 stainless steel. Five types of surface finish corresponding to roughness values R a between 0.03 and 0.89 w m were produced. Adhesion of all four bacteria was minimal at R a =0.16 w m, whereas smoother and rougher surfaces gave rise to more adhesion. This surface exhibited parallel scratches of 0.7 w m, in which a high proportion of bacteria of three of the strains aligned. Reduced overall adhesion was attributed to unfavorable interactions between this surface and bacteria oriented other than parallel to the scratches. Interaction energy calculations and considerations of micro-geometry confirmed this mechanism. Rougher surfaces exhibiting wider scratches allowed a higher fraction of bacteria to adhere in other orientations, whereas the orientation of cells adhered to the smoothest surface was completely random.     

Inactivation Kinetics and Mechanism of a Human Norovirus Surrogate on Stainless Steel Coupons via Chlorine Dioxide Gas

Acute gastroenteritis caused by human norovirus is a significant public health issue. Fresh produce and seafood are examples of high-risk foods associated with norovirus outbreaks. Food contact surfaces also have the potential to harbor noroviruses if exposed to fecal contamination, aerosolized vomitus, or infected food handlers. Currently, there is no effective measure to decontaminate norovirus on food contact surfaces. Chlorine dioxide (ClO₂) gas is a strong oxidizer and is used as a decontaminating agent in food processing plants. The objective of this study was to determine the kinetics and mechanism of ClO₂ gas inactivation of a norovirus surrogate, murine norovirus 1 (MNV-1), on stainless steel (SS) coupons. MNV-1 was inoculated on SS coupons at the concentration of 10⁷ PFU/coupon. The samples were treated with ClO₂ gas at 1, 1.5, 2, 2.5, and 4 mg/liter for up to 5 min at 25°C and a relative humidity of 85%, and virus survival was determined by plaque assay. Treatment of the SS coupons with ClO₂ gas at 2 mg/liter for 5 min and 2.5 mg/liter for 2 min resulted in at least a 3-log reduction in MNV-1, while no infectious virus was recovered at a concentration of 4 mg/liter even within 1 min of treatment. Furthermore, it was found that the mechanism of ClO₂ gas inactivation included degradation of viral protein, disruption of viral structure, and degradation of viral genomic RNA. In conclusion, treatment with ClO₂ gas can serve as an effective method to inactivate a human norovirus surrogate on SS contact surfaces.     

微重力对血管及血管内皮细胞的影响

血管系统功能紊乱是微重力诱导立位耐力不良发生的重要因素之一。血管内皮细胞是覆盖在血管内壁上组成血管管腔面的一层单层细胞,是血管壁的重要组成部分,并且在血管功能调控中起到渗透屏障、调节舒缩等重要作用。近年研究发现,微重力可对不同部位的血管系统和血管内皮细胞产生不同的影响,比如可使脑动脉缩血管反应性增加、舒血管反应性下降,颈动脉和腹主动脉缩血管和舒血管反应性下降,肺动脉缩血管反应性下降、舒血管反应性增加,肠系膜动静脉和下肢动脉缩血管反应性下降。另外,微重力可促进大血管来源的内皮细胞生长,但抑制微血管来源的内皮细胞的生长。本文就微重力对血管及血管内皮细胞影响的研究进展作一概述。     

几丁聚糖在医用不锈钢表面作生物涂层的可行性

针对生物材料医用不锈钢的应用及其植入人体存在的问题,介绍了目前金属材料表面改性的主要方法和最新研究进展,并综述了几丁聚糖的性能和国内外对几丁聚糖的研究方向,在此基础上重点探索了几丁聚糖在医用不锈钢表面作生物涂层的可能性及其意义。     

Inactivation of Influenza A Virus on Copper versus Stainless Steel Surfaces

Influenza A virus particles (2 × 10⁶) were inoculated onto copper or stainless steel and incubated at 22°C at 50 to 60% relative humidity. Infectivity of survivors was determined by utilizing a defined monolayer with fluorescent microscopy analysis. After incubation for 24 h on stainless steel, 500,000 virus particles were still infectious. After incubation for 6 h on copper, only 500 particles were active.     

The Effects of Hyperbaric Oxygen Therapy on Post-Training Recovery in Jiu-Jitsu Athletes

Objectives

The present study aimed to evaluate the effects of using hyperbaric oxygen therapy during post-training recovery in jiu-jitsu athletes.

Methods

Eleven experienced Brazilian jiu-jitsu athletes were investigated during and following two training sessions of 1h30min. Using a cross-over design, the athletes were randomly assigned to passive recovery for 2 hours or to hyperbaric oxygen therapy (OHB) for the same duration. After a 7-day period, the interventions were reversed. Before, immediately after, post 2 hours and post 24 hours, blood samples were collected to examine hormone concentrations (cortisol and total testosterone) and cellular damage markers [creatine kinase (CK), aspartate aminotransferase (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH)]. Moreover, the rating of perceived exertion (RPE) and recovery (RPR) scales were applied.

Results

Final lactate [La] values (control: 11.9 ± 1.4 mmol/L, OHB: 10.2 ± 1.4 mmol/L) and RPE [control: 14 (13–17 a.u.), OHB: 18 (17–20 a.u.)] were not significantly different following the training sessions. Furthermore, there was no difference between any time points for blood lactate and RPE in the two experimental conditions (P>0.05). There was no effect of experimental conditions on cortisol (F_1,20 = 0.1, P = 0.793, η² = 0.00, small), total testosterone (F_1,20 = 0.03, P = 0.877, η² = 0.00, small), CK (F_1,20 = 0.1, P = 0.759, η² = 0.01, small), AST (F_1,20 = 0.1, P = 0.761, η² = 0.01, small), ALT (F_1,20 = 0.0, P = 0.845, η² = 0.00, small) or LDH (F_1,20 = 0.7, P = 0.413, η² = 0.03, small). However, there was a difference between the two experimental conditions in RPR with higher values at post 2 h and 24 h in OHB when compared to the control condition (P<0.05).

Conclusions

Thus, it can be concluded that OHB exerts no influence on the recovery of hormonal status or cellular damage markers. Nonetheless, greater perceived recovery, potentially due to the placebo effect, was evident following the OHB condition.     

The Detection of Microorganisms and Organic Material on Stainless Steel Food Contact Surfaces

Few methods are available for the differentiation of microorganism and organic material on surfaces, although such mixtures are commonplace, particularly in the food industry, where food debris (soil) and microorganisms frequently foul food contact surfaces and pose challenges in terms of hygiene and cleanability. It would be of value to discern any differences in removal or persistence on surfaces. This review considers some methods which are available. Direct epifluorescence microscopy (DEM) enables visual differentiation, but traditional microbiological culture methods cannot detect organic soil. Atomic force microscopy (AFM) provides images of the surface on the nanometer scale, with minimal preparation, and is able to visualise both cellular and acellular components of the mixture, particularly prior to cleaning. Confocal laser scanning microscopy (CLSM) also has potential in this area. Surface sensitive methods such as X-Ray photoelectron spectroscopy (XPS) and Time-of-flight secondary ion mass spectrometry (ToFSIMS) provide information on chemical species present on a surface. Those chemical species more likely on microbial cells may be differentiated from those more likely in a specified organic soil, thus comparisons may be made as to differential removal of the organic soil and microbial cells. These methods may be of value in studies on the fouling and cleanability of surfaces.     

高压氧对正常及SIRS大鼠脾T淋巴细胞的影响

本实验以SIRS为基础,以免疫功能和炎症反应中具有代表性的脾T淋巴细胞为研究对象,观察高压氧对正常机体以及SIRS状态机体的影响并探讨其可能的机制。健康雄性SD大鼠40只,体重约140~180 g,随机分为5组,每组8只。A组：腹腔注射生理盐水（5 mL/kg）;B组：腹腔注射等量生理盐水,做3次高压氧;C组：腹腔注射酵母多糖-石蜡悬液（500 mg/kg）;D组：腹腔注射酵母多糖-石蜡悬液（500 mg/kg）,做1次高压氧治疗;E组：腹腔注射酵母多糖-石蜡悬液（500 mg/kg）,做3次高压氧治疗。采用流式细胞仪计算大鼠脾脏淋巴细胞数量及比例。高压氧治疗（B组）降低正常大鼠外周血CD4＋T细胞百分比（P〈0.01）,对CD8＋T细胞无影响,因此CD4＋/CD8＋T细胞比值下降（P〈0.05）。酵母多糖腹腔注射（C组）使大鼠外周血CD4＋、CD8＋T细胞均减少（P〈0.01）,但CD4＋/CD8＋T细胞比值不变。1次和3次HBO治疗（D和E组）可使酵母多糖所致CD4＋T细胞减少（C组）明显恢复（P〈0.01,P〈0.05）,故CD3＋CD4＋/CD3＋CD8＋比值升高（P〈0.01,P〈0.05）,HBO几乎不影响CD8＋T细胞比例（P〉0.05）。酵母多糖导致大鼠脾脏CD4＋和CD8＋T细胞比例减少;高压氧可减少正常大鼠脾脏CD4＋T细胞比例,而增加SIRS脾脏的CD4＋T细胞比例,而对CD8＋T细胞无影响。     

Listeria monocytogenes Attachment to and Detachment from Stainless Steel Surfaces in a Simulated Dairy Processing Environment

The presence of pathogens in dairy products is often associated with contamination via bacteria attached to food-processing equipment, especially from areas where cleaning/sanitation is difficult. In this study, the attachment of Listeria monocytogenes on stainless steel (SS), followed by detachment and growth in foods, was evaluated under conditions simulating a dairy processing environment. Initially, SS coupons were immersed in milk, vanilla custard, and yogurt inoculated with the pathogen (10⁷ CFU/ml or CFU/g) and incubated at two temperatures (5 and 20°C) for 7 days. By the end of incubation, cells were mechanically detached from coupons and used to inoculate freshly pasteurized milk which was subsequently stored at 5°C for 20 days. The suspended cells in all three products in which SS coupons were immersed were also used to inoculate freshly pasteurized milk (5°C for 20 days). When SS coupons were immersed in milk, shorter lag phases were obtained for detached than for planktonically grown cells, regardless of the preincubation temperature (5 or 20°C). The opposite was observed when custard incubated at 20°C was used to prepare the two types of inocula. However, in this case, a significant increase in growth rate was also evident when the inoculum was derived from detached cells. In another parallel study, while L. monocytogenes was not detectable on SS coupons after 7 days of incubation (at 5°C) in inoculated yogurt, marked detachment and growth were observed when these coupons were subsequently transferred and incubated at 5°C in fresh milk or/and custard. Overall, the results obtained extend our knowledge on the risk related to contamination of dairy products with detached L. monocytogenes cells.Listeria monocytogenes is ubiquitous in nature due to its inherent ability to survive and grow under a wide range of adverse environmental conditions, such as refrigeration temperatures, high acidity and salinity, and reduced water activity (16). This microorganism is a major concern for the food industry, since it is the causal agent of listeriosis, a severe disease with high hospitalization and case-fatality rates (approximately 91% and 30%, respectively) (25). According to the European Centre for Disease Control and Prevention, listeriosis was the fifth most common zoonotic infection in Europe in 2006 (14), while it accounts for approximately 28% of the deaths resulting from food-borne illnesses in the United States (34).In the food industry, inadequately cleaned food-processing equipment (e.g., stainless steel [SS] surfaces) constitutes a potential source for L. monocytogenes, resulting in contamination of foods which come in contact with such equipment (36). Even though adherence to strict sanitation practices should minimize the risk of survivors on surfaces, existing evidence suggests that a considerable risk may occur in sites of processing plants which are not easily cleaned or sanitized, such as those that do not allow direct access of sanitation equipment for abrasion (e.g., edges, convex surfaces, etc.) (43, 45). Attachment to surfaces is believed to be important for the survival and persistence of this pathogen in such environments, with some strains able to remain on equipment surfaces for several years (32, 37). Thus, L. monocytogenes has been shown to adhere to and form biofilms on various food contact surfaces under laboratory conditions (3, 42, 44). Furthermore, attached L. monocytogenes cells are more difficult to mechanically remove from surfaces and are more resistant to sanitizers than their free-living counterparts (15, 40).Dairy products have been implicated in outbreaks of listeriosis (10, 31). However, most of the in vitro studies of the growth and survival of L. monocytogenes in such products have used strains previously cultivated planktonically (41). Although the results obtained in these studies are of great value, such studies have not taken into consideration that cells contaminating a product in a food-processing environment are usually attached to surfaces enclosed in biofilms. Limited information is available on the kinetic behavior of L. monocytogenes in dairy products inoculated with detached cells, although preincubation conditions have been shown to influence subsequent growth and survival of L. monocytogenes in foods (7, 13, 17, 18). Given the major physiological differences between attached and planktonic cells (15, 27, 48), an effect on subsequent growth might be possible.Considering the above, the main objective of the present study was to assess the influence of L. monocytogenes preincubation conditions with respect to mode of growth (either attached to SS or grown suspended in dairy products) on the subsequent growth of this pathogen in milk (at 5°C for 20 days). To prepare the two types of inocula, two different growth media (milk and vanilla custard) and temperatures (5 and 20°C) were studied. The unforced detachment of L. monocytogenes cells from SS coupons and growth in two dairy products (milk and custard) at 5°C for 20 days was also evaluated. In the latter case, previous attachment of cells to the coupons was done under especially adverse preincubation conditions (in yogurt at 5°C for 7 days).     

Effect of Flagella on Initial Attachment of Listeria monocytogenes to Stainless Steel

At 22°C a flagellin mutant of Listeria monocytogenes was found to attach to stainless steel at levels 10-fold lower than wild-type cells, even under conditions preventing active motility. At 37°C, when flagella are not produced, attachment of both strains was identical. Therefore, flagella per se facilitate the early stage of attachment.