Analysis of Vibrio seventh pandemic island II and novel genomic islands in relation to attachment sequences among a wide variety of Vibrio cholerae strains

Vibrio cholerae O1 El Tor, the pathogen responsible for the current cholera pandemic, became pathogenic by acquiring virulent factors including Vibrio seventh pandemic islands (VSP)‐I and ?II. Diversity of VSP‐II is well recognized; however, studies addressing attachment sequence left (attL) sequences of VSP‐II are few. In this report, a wide variety of V. cholerae strains were analyzed for the structure and distribution of VSP‐II in relation to their attachment sequences. Of 188 V. cholerae strains analyzed, 81% (153/188) strains carried VSP‐II; of these, typical VSP‐II, and a short variant was found in 36% (55/153), and 63% (96/153), respectively. A novel VSP‐II was found in two V. cholerae non‐O1/non‐O139 strains. In addition to the typical 14‐bp attL, six new attL‐like sequences were identified. The 14‐bp attL was associated with VSP‐II in 91% (139/153), whereas the remaining six types were found in 9.2% (14/153) of V. cholerae strains. Of note, six distinct types of the attL‐like sequence were found in the seventh pandemic wave 1 strains; however, only one or two types were found in the wave 2 or 3 strains. Interestingly, 86% (24/28) of V. cholerae seventh pandemic strains harboring a 13‐bp attL‐like sequence were devoid of VSP‐II. Six novel genomic islands using two unique insertion sites to those of VSP‐II were identified in 11 V. cholerae strains in this study. Four of those shared similar gene clusters with VSP‐II, except integrase gene.

     

Characterization of new anti-IL-6 antibodies revealed high potency candidates for intracellular cytokine detection and specific targeting of IL-6 receptor binding sites

Interleukin-6 (IL-6) expression and secretion, induced by inflammatory processes, stimulate the acute phase response cascade. The overexpression of IL-6 contributes to a variety of inflammatory diseases, e.g. rheumatoid arthritis, Castleman’s disease, multiple myeloma, and prostate cancer. Screening for high amounts of IL-6 in the patients’ blood serum can be crucial for an adequate treatment. In this study, five novel murine monoclonal antibodies (mAbs) reactive to human IL-6 were generated. The mAbs were characterized for potential diagnostic purposes and recombinant antibodies were derived thereof. Initial epitope mapping using a combination of blocking experiments and Hyper-IL-6, a fusion protein consisting of IL-6 and the soluble IL-6 receptor revealed distinct but overlapping binding sites. At least one of the mAbs was found to interact with the region of IL-6/ IL-R complex formation. Three mAbs were applied successfully in intracellular staining by flow cytometry, whereas one of the mAbs showed comparable binding as a reference reagent. Furthermore, the mAbs were tested for applications in various immunological assays such as ELISA, Western blot and surface plasmon resonance spectroscopy (SPR), using IL-6 from commercial sources as well as in-house produced protein (IL-6_IME). The limit of detection was determined by sandwich ELISA (0.5 ng/mL, SD ±0.005). Our results also demonstrated that the recombinant IL- 6 produced was functional and correctly folded. These findings support the use of the generated mAb clones as promising candidates for application in various immunological assays for diagnostic and scientific purposes.     

Cross‐talk between monocyte invasion and astrocyte proliferation regulates scarring in brain injury

Scar formation after brain injury is still poorly understood. To further elucidate such processes, here, we examine the interplay between astrocyte proliferation taking place predominantly at the vascular interface and monocyte invasion. Using genetic mouse models that decrease or increase reactive astrocyte proliferation, we demonstrate inverse effects on monocyte numbers in the injury site. Conversely, reducing monocyte invasion using CCR2^?/? mice causes a strong increase in astrocyte proliferation, demonstrating an intriguing negative cross‐regulation between these cell types at the vascular interface. CCR2^?/? mice show reduced scar formation with less extracellular matrix deposition, smaller lesion site and increased neuronal coverage. Surprisingly, the GFAP⁺ scar area in these mice is also significantly decreased despite increased astrocyte proliferation. Proteomic analysis at the peak of increased astrocyte proliferation reveals a decrease in extracellular matrix synthesizing enzymes in the injury sites of CCR2^?/? mice, highlighting how early key aspects of scar formation are initiated. Taken together, we provide novel insights into the cross‐regulation of juxtavascular proliferating astrocytes and invading monocytes as a crucial mechanism of scar formation upon brain injury.     

Competition matters: Determining the drivers of land snail community assembly among limestone karst areas in northern Vietnam

The insular limestone karsts of northern Vietnam harbor a very rich biodiversity. Many taxa are strongly associated with these environments, and individual species communities can differ considerably among karst areas. The exact processes that have shaped the biotic composition of these habitats, however, remain largely unknown. In this study, the role of two major processes for the assembly of snail communities on limestone karsts was investigated, interspecific competition and filtering of taxa due to geographical factors. Communities of operculate land snails of the genus Cyclophorus were studied using the dry and fluid‐preserved specimen collections of the Natural History Museum, London. Phylogenetic distances (based on a Bayesian analysis using DNA sequence data) and shell characters (based on 200 semilandmarks) were used as proxies for ecological similarity and were analyzed to reveal patterns of overdispersion (indicating competition) or clustering (indicating filtering) in observed communities compared to random communities. Among the seven studied karst areas, a total of 15 Cyclophorus lineages were found. Unique communities were present in each area. The analyses revealed phylogenetic overdispersion in six and morphological overdispersion in four of seven karst areas. The pattern of frequent phylogenetic overdispersion indicated that competition among lineages is the major process shaping the Cyclophorus communities studied. The Coastal Area, which was phylogenetically overdispersed, showed a clear morphological clustering, which could have been caused by similar ecological adaptations among taxa in this environment. Only the community in the Cuc Phuong Area showed a pattern of phylogenetic clustering, which was partly caused by an absence of a certain, phylogenetically very distinct group in this region. Filtering due to geographical factors could have been involved here. This study shows how museum collections can be used to examine community assembly and contributes to the understanding of the processes that have shaped karst communities in Vietnam.     

光敏核不育水稻农垦58S 41 kD蛋白质的N—端序列分析

光敏核不育性受1对或2对或3对隐性主基因控制,这反应了光敏核不育特性遗传机制的复杂性。张端品等用形态标记法将农垦58S光敏核不育基因定位于第5染色体。胡学应和万邦惠用同工酶法以农垦58S/02428 F_2群体为材料,将光敏核不育基因定位于第6和11染色体;Zhang等用RFLP法以32001S/明恢63 F_2群体为材料将不育基因定位于第3和7染色体。这三种方法所得到的定位结果完全不同,综合起来,第3、5、6、7和11染色体均有光敏核不育基因的位点,由此结果可得出两种解释:1.光敏核不育性由多对基因、至少5对基因控制;2.上述定位方法均是以不育(可育)性状在F_2群体中的分离模式为依据,育性划分界线的不同将会造成分离群体中单株表现值的差异,从而影响定位结果的精确性;再者不同实验室使用的材料不一致,已知不同遗传背景和光温条件影响光敏核不育基因的表达。因此,染色体定位结果有待确证。光敏核不育基因在染色体上定位的复杂性和不一致在某种程度上影响了基因克隆和光敏核不育分子机制的研究。无论光敏核不育性的遗传机制如何复杂,上述结果     

蝮蛇抗栓酶对不稳定性心绞痛患者血中部分凝血及纤溶指标的影响

测定３８例不稳定性心绞痛（ＵＡＰ）患者血中纤维蛋白原（Ｆｇ）含量、组织型纤溶酶原激活物（ｔ－ＰＡ）活性、血管性假血友病因子（ｖＷＦ）活性和血小板聚集率水平（ＰＡｇＴ）并与２１名正常人对比。患者中１８例用蝮蛇抗栓酶治疗,２０例行常规治疗。结果显示：ＵＡＰ患者血中ＰＡＩ－１、ｖＷＦ以及ＰＡｇＴ水平明显增高,ｔ－ＰＡ水平明显降低;蝮蛇抗栓酶组治疗后血中Ｆｇ、ＰＡＩ－１、ＰＡｇＴ水平均明显下降,使ｔ－ＰＡ水平明显升高;常规治疗组治疗前后各项指标无明显变化。认为蝮蛇抗栓酶对ＵＡＰ有可靠疗效