低温氧等离子体杀灭铜绿假单胞菌的效果及机理

【目的】本文采用低温氧等离子体,在自行设计的远程等离子体反应装置中,对位于不同放电区域（放电区,余辉区,远程区）的模拟染菌载体聚对苯二甲酸乙二醇酯（PET）表面的铜绿假单胞菌(Pseudomonas aeruginosa)的杀灭效果和机理进行了研究。【方法】采用扫描电子显微镜观察了等离子体处理前后细菌细胞的形貌变化,采用考马斯亮蓝法测定了等离子体处理后细菌蛋白质泄漏量,采用双悬浮探针对氧等子体的电子温度和离子浓度以及电子自旋共振波谱对自由基浓度进行了测定。【结果】强放电区、余辉区和远程区处理30s后的灭菌效果分别为4.2 ,3.8和2.6;扫描电镜观察结果和蛋白泄漏量测定结果证明细菌细胞被损毁,在强放电区是电子、离子、自由基和紫外光子的协同作用,而在余辉区和远程区的灭杀作用主要因自由基所为。【结论】证明该反应装置可有效实现活性粒子的分离,在远程等离子体场中揭示了等离子体灭菌的规律和机理。     

Platelet-Rich Plasma: Support for Its Use in Wound Healing

Previous topical growth factor studies have shown that recombinant human platelet-derived growth factor-BB isomer (rhPDGF-BB) is an efficacious treatment of chronic diabetic foot ulceration. A newer treatment, autologous platelet-rich plasma (PRP), represents a greater similarity to the natural healing process as a composite of multiple growth factors, is safe due to its autologous nature, and is produced as needed from patient blood. A review of the literature shows few studies performed with scientific rigor, although the safety of PRP appears to be validated. As the use of PRP increases, additional studies may establish PRP as an efficacious treatment modality and guide future treatment of chronic diabetic foot ulceration.     

Erythrocytes serve as a reservoir for cellular and extracellular sphingosine 1‐phosphate

Sphingosine 1‐phosphate (S1P) in blood is phosphorylated, stored, and transported by red blood cells (RBC). Release of S1P from RBC into plasma is a regulated process that does not occur in plasma‐ or serum‐free media. Plasma fractionation and incubations with isolated and recombinant proteins identified high density lipoprotein (HDL) and serum albumin (SA) as non‐redundant endogenous triggers for S1P release from RBC. S1P bound to SA and HDL was able to stimulate the S1P₁ receptor in calcium flux experiments. The binding capability of acceptor molecules triggers S1P release, as demonstrated with the anti‐S1P antibody Sphingomab?. More S1P was extracted from RBC membranes by HDL than by SA. Blood samples from anemic patients confirmed a reduced capacity for S1P release in plasma. In co‐cultures of RBC and endothelial cells (EC), we observed transcellular transportation of S1P as a second function of RBC‐associated S1P in the absence of SA and HDL and during tight RBC‐EC contact, mimicking conditions in tissue interstitium and capillaries. In contrast to S1P bound to SA and HDL, RBC‐associated S1P was significantly incorporated by EC after S1P lyase (SGPL1) inhibition. RBC‐associated S1P, therefore, has two functions: (1) It contributes to the cellular pool of SGPL1‐sensitive S1P in tissues after transcellular transportation and (2) it helps maintain extracellular S1P levels via SA and HDL independently from SGPL1 activity. J. Cell. Biochem. 109: 1232–1243, 2010. © 2010 Wiley‐Liss, Inc.     

Influence of seminal plasma on fertility of fresh and frozen-thawed stallion epididymal spermatozoa

The use of epididymal stallion spermatozoa for routine artificial insemination can secure easy future use of valuable genetics after unforeseen death or injury of a valuable stallion.     

Lysozyme activities and immunoglobulin concentrations in seminal plasma and spermatozoa of different teleost species and indications on its significance for sperm function

The occurrence of lysozyme and immunoglobulin (Ig) in semen of different teleost species (brown trout—Salmo trutta, perch—Perca fluviatilis, burbot—Lota lota) was studied. In all investigated species lysozyme activities (1.13-1.45 U ml⁻¹) and Ig concentrations (T-Ig: 1.11-1.61 μg ml⁻¹, IgG [measured only in brown trout]: 1.49 μg ml⁻¹) were detected in seminal plasma. Ig was also found in spermatozoa (T-Ig: 0.234-0.357 μg/g protein, IgG: 0.198 μg ml⁻¹) while spermatozoal lysozyme activities were low and fluctuating (0.093-0.164 U/g protein). In Salmo trutta lysozyme activities and immunoglobulin levels were compared between semen samples with high and low sperm motility as motility is an indicator for sperm fertility. Lysozyme activities were higher in seminal plasma of samples with high motility than in those with low motility while seminal plasma and spermatozoal immunoglobulin concentrations (T-Ig, IgG) were increased in samples with low motility in comparison to samples with high motility. Seminal plasma and spermatozoal IgG concentrations and seminal plasma lysozyme activities showed significant correlations with the sperm motility rate and swimming velocity. Moreover, lysozyme improved the viability of spermatozoa in in vitro experiments. Possible physiological meanings of these results are discussed.     

Identification of tubby and tubby-like protein 1 as eat-me signals by phage display

Phagocytosis is an important process for the removal of apoptotic cells or cellular debris. Eat-me signals control the initiation of phagocytosis and hold the key for in-depth understanding of its molecular mechanisms. However, because of difficulties to identify unknown eat-me signals, only a limited number of them have been identified and characterized. Using a newly developed functional cloning strategy of open reading frame (ORF) phage display, we identified nine putative eat-me signals, including tubby-like protein 1 (Tulp1). This further led to the elucidation of tubby as the second eat-me signal in the same protein family. Both proteins stimulated phagocytosis of retinal pigment epithelium (RPE) cells and macrophages. Tubby-conjugated fluorescent microbeads facilitated RPE phagocytosis. Tubby and Tulp1, but not other family members, enhanced the uptake of membrane vesicles by RPE cells in synergy. Retinal membrane vesicles of Tubby mice and Tulp1^−/− mice showed reduced activities for RPE phagocytosis, which were compensated by purified tubby and Tulp1, respectively. These data reveal a novel activity of tubby and Tulp1, and demonstrate that unbiased identification of eat-me signals by the broadly applicable strategy of ORF phage display can provide detailed insights into phagocyte biology.     

A fluorimetric semi-microplate format assay of protein carbonyls in blood plasma

Oxidative stress, originating from reactive oxygen species (ROS), has been implicated in aging and various human diseases. The ROS generated can oxidize proteins producing protein carbonyl derivatives. The level of protein carbonyls in blood plasma has been used as a measure of overall oxidative stress in the body. Classically, protein carbonyls have been quantitated spectrophotometrically by directly reacting them with 2,4-dinitrophenylhydrazine (DNPH). However, the applicability of this method to biological samples is limited by its low inherent sensitivity. This limitation has been overcome by the development of sensitive enzyme-linked immunosorbent assay (ELISA) methods to measure protein carbonyls. As part of the Healthy Aging in Neighborhoods of Diversity across the Lifespan (HANDL) study, oxidative stress in humans was quantified by measuring blood plasma protein carbonyls using the two commercially available ELISA kits and the spectrophotometric DNPH assay. Surprisingly, two ELISA methods gave very different values for protein carbonyls, both of which were different from the value of the spectrophotometric method. We have developed a fluorescent semi-microplate format assay of protein carbonyls involving direct reaction of protein carbonyls with fluorescein thiosemicarbazide that correlates (R = 0.992) with the direct spectrophotometric method. It has a coefficient of variation of 4.99% and is at least 100 times more sensitive than the spectrophotometric method.     

Multiple pathways leading from the T-cell antigen receptor to the actin cytoskeleton network

Dynamic rearrangements of the actin cytoskeleton, following T-cell antigen receptor (TCR) engagement, provide the structural matrix and flexibility to enable intracellular signal transduction, cellular and subcellular remodeling, and driving effector functions. Recently developed cutting-edge imaging technologies have facilitated the study of TCR signaling and its role in actin-dependent processes. In this review, we describe how TCR signaling cascades induce the activation of actin regulatory proteins and the formation of actin networks, and how actin dynamics is important for T-cell homeostasis, activation, migration, and other effector functions.     

Pharmacology of mitochondrial potassium channels: dark side of the field

Mitochondrial potassium channels play an important role in cytoprotection. Potassium channels in the inner mitochondrial membrane are modulated by inhibitors and activators (potassium channel openers) previously described for plasma membrane potassium channels. The majority of mitochondrial potassium channel modulators exhibit a broad spectrum of off-target effects. These include uncoupling properties, inhibition of the respiratory chain and effects on cellular calcium homeostasis. Therefore, the rational application of channel inhibitors or activators is crucial to understanding the cellular consequences of mitochondrial channel inhibition or activation. Moreover, understanding their side-effects should facilitate the design of a specific mitochondrial channel opener with cytoprotective properties. In this review, we discuss the complex interactions of potassium channel inhibitors and activators with cellular structures.