Heterotylenchus antumnalis. Hemocytic reactions and capsule formation in the host, Musca domestica

Failure of the nematode H. autumnalis to develop in M. domestica is attributed to the defense reaction of host larvae to the infective, gamogenetic stage of the parasite. The defense reaction involves melanization and encapsulation of the parasite, and is manifested as changes in the hemocyte picture of the host.     

Cloning of a novel crystal protein gene cry 1K from Bacillus thuringiensis subsp. morrisoni

Abstract In Escherichia coli with group II capsules, the synthesis of capsular polysaccharide and its cellular expression are encoded by the kps gene cluster, which is composed of three regions. The central region 2 encodes proteins involved in polysaccharide synthesis, and the flanking regions 1 and 3 direct the translocation of the finished polysaccharide across the cytoplasmic membrane and its surface expression. The kps genes of E. coli with the group II capsular K5 polysaccharide, have been cloned and sequenced. Region 1 contains the kps E, D, U, C and S genes. In this communication we describe the overexpression of the kps D and kps U genes as well as the isolation of the KpsU protein from the recombinant bacteria by chloroform treatment. The purified KpsU protein exhibited CMP-Kdo-synthetase activity. The N-terminal sequence and two internal peptide sequences of the isolated protein are in agreement with that previously predicted from the DNA sequence of the kps U gene. The kinetic data of the CMP-Kdo-synthetase participating in K5 capsule expression (K-CMP-Kdo-synthetase) differ from those described for the CMP-Kdo-synthetase, participating in lipopolysaccharide synthesis (L-CMP-Kdo-synthetase).     

Dissection of the Yersinia enterocolitica virulence plasmid pYVO8 into an operating unit and virulence gene modules

Abstract Mesophilic Aeromonas hydrophila from serotypes O:11 and O:34 grown in a glucose-rich medium produce a capsule that can be seen under light and electron microscopy. The purified capsular polysaccharide has a composition qualitatively similar for strains O:11 and O:34, but quantitatively different. The capsular polysaccharides were immunogenic in rabbits, and did not cross-react with specific antibodies against either purified lipopolysaccharide from strains O:34 or O:11 or against the S-layer characteristic of strains from serotype O:11.     

Monoclonal antibodies against O and K antigens of uropathogenic Escherichia coli O4 : K12 : H− as opsonins

Abstract Monoclonal antibodies of subclasses IgG1 and IgG2b and specific for the O4 antigen of Escherichia coli 20025 (O4 : K12 : H⁻) and the capsular K12 polysaccharide of the same strain (IgM) were obtained with the hybridoma technique using spleen cells from Balb/c mice, immunized with a crude bacterial extract, and Sp2/O-Ag8 myeloma cells. The anti-O4 antibodies reacted exclusively with the O4 lipopolysaccharide and not with those from serologically O-cross reactive E. coli . The anti-K12 antibodies recognized as epitope (part of) the KDO moiety of the capsular K12 polysaccharide. Not only anti-K12, but also anti-O4 antibodies effectively phagoopsonized encapsulated E. coli 20025. The opsonized bacteria were killed in subsequent in vitro phagocytosis by human leokocytes in the presence of human serum complement.     

海珠益肝胶囊对免疫性肝损伤模型小鼠的保护作用

目的：观察海珠益肝胶囊对卡介苗（BCG）加脂多糖（LPS）诱导的小鼠免疫性肝损伤的防护作用。方法：采用卡介苗（BCG）加脂多糖（LPS）诱导小鼠免疫性肝损伤,通过检测小鼠的血清谷丙转氨酶（ALT）和谷草转氨酶（AST）活性及肝脏病理变化来研究海珠益肝胶囊的保肝功能。结果：海珠益肝胶囊防治组小鼠血清ALT及AST活性比模型组显著降低,两组比较,差异有统计学意义。海珠益肝胶囊可明显减轻肝组织病理损伤,以大剂量组作用最佳;海珠益肝胶囊的使用使免疫性肝损伤小鼠肝细胞凋亡减少,且有剂量依赖关系。结论：海珠益肝胶囊对BCG加LPS诱导小鼠产生免疫性肝炎的模型免疫性肝损伤具有显著的保护作用。     

4株具有荚膜的白假丝酵母菌的分离与鉴定

取临床标本（性病门诊病人阴道分泌物）直接涂片染色镜检及用沙保氏琼脂平板分离培养、作涂片革兰染色镜检、出芽试验、厚膜孢子形成试验、糖发酵试验等鉴定菌种;小白鼠与家兔试验、荚膜肿胀试验、透射电镜等观察荚膜,观察白假丝酵母菌临床分离菌株（C1-1、C1-2、C1-3、C1-4）的荚膜结构并探讨其形成条件。结果显示：（1）C1-1、C1-2、C1-3、C1-4四株临床分离菌株均为革兰阳性、念珠状菌;能形成芽管、假菌丝、厚膜孢子;能发酵葡萄糖和麦芽糖产酸又产气;发酵蔗糖产酸不产气;不发酵乳糖。（2）在感染小白鼠及家兔体内均可形成荚膜,荚膜层的厚度可因不同环境而有显著差异（P〈0．01或〈0．05）,边界明显;荚膜肿胀试验阳性。4株临床分离菌株均可被鉴定为具有荚膜的白假丝酵母菌。     

参元益气活血胶囊联合心痛贴穴位贴敷对不稳定性心绞痛气虚血瘀证患者脂代谢和氧化应激的影响

摘要 目的：观察参元益气活血胶囊联合心痛贴穴位贴敷对不稳定性心绞痛（UA）气虚血瘀证患者脂代谢和氧化应激的影响。方法：按照随机数字表法将2020年3月~2022年9月期间首都医科大学附属北京中医医院收治的100例UA患者分为对照组（常规西医治疗和心痛贴穴位贴敷）和研究组（对照组的基础上接受参元益气活血胶囊治疗），各为50例。对比两组中医证候积分、心绞痛发作次数和持续时间、脂代谢指标[总胆固醇（TC）、甘油三酯（TG）、低密度脂蛋白胆固醇（LDL-C）、高密度脂蛋白胆固醇（HDL-C）]、氧化应激指标[超氧化物歧化酶（SOD）、丙二醛（MDA）]、心功能指标[左心室射血分数（LVEF）、心输出量（CO）、左心室舒张末期内径（LVEDD）]。结果：两组治疗4周后胸痛、胸闷、气短、心悸、神倦乏力、自汗、不寐评分均下降，且研究组均低于对照组（P<0.05）。两组治疗4周后心绞痛发作次数减少，持续时间缩短，且研究组改善幅度大于对照组（P<0.05）。两组治疗4周后TG、TC、LDL-C下降，HDL-C升高，且研究组改善幅度大于对照组（P<0.05）。两组治疗4周后SOD升高，MDA下降，且研究组改善幅度大于对照组（P<0.05）。两组治疗4周后LVEF、CO升高，LVEDD下降，且研究组改善幅度大于对照组（P<0.05）。结论：参元益气活血胶囊联合心痛贴穴位贴敷治疗UA气虚血瘀证患者，可减少心绞痛发作次数，缩短持续时间，促进临床症状改善，改善心功能、脂代谢和氧化应激水平。     

Envelope ultrastructure of uncultured naturally occurring magnetotactic cocci

Magnetotactic bacteria are microorganisms that respond to magnetic fields. We studied the surface ultrastructure of uncultured magnetotactic cocci collected from a marine environment by transmission electron microscopy using freeze-fracture and freeze-etching. All bacteria revealed a Gram-negative cell wall. Many bacteria possessed extensive capsular material and a S-layer formed by particles arranged with hexagonal symmetry. No indication of a metal precipitation on the surface of these microorganisms was observed. Numerous membrane vesicles were observed on the surface of the bacteria. Flagella were organized in bundles originated in a depression on the surface of the cells. Occasionally, a close association of the flagella with the magnetosomes that remained attached to the replica was observed. Capsules and S-layers are common structures in magnetotactic cocci from natural sediments and may be involved in inhibition of metal precipitation on the cell surface or indirectly influence magnetotaxis.     

Morphological and physical characterization of the capsular layer of Vibrio cholerae O139

The morphological and physical characteristics of the capsule of Vibrio cholerae O139 were examined. An electron microscopic study using the freeze-substitution technique showed that all of the V. cholerae strains of the O139 serogroup examined have a very thin fibrous layer on the outside of the outer membrane. In contrast, the mutants of strain O139, strain MO10T4 (which lacks capsule synthesis), and strain Bengal-2R1 (which fails to synthesize both the capsule and the O-antigen of lipopolysaccharide) were all found to have lost the surface layer. In addition, the capsule layer could also not be observed on the surface of V. cholerae strain O1. To determine the biological characteristics of the capsule of strains of the O139 serogroup, we investigated the serum killing activity and bacterial phagocytosis by polymorphonuclear leukocytes. The O139 strains were more resistant to the serum killing activity than were the V. cholerae O1 strain and the O139 mutant strains, thus suggesting that the existence of the capsule gave a serum-resistant character to the O139 strains. The surface character of the O139 strains had the same hydrophobic character as did that of the O139 mutant strains and the O1 strain. In addition, all the V. cholerae O1 and O139 strains examined, including the mutant strains, were effectively ingested by the human polymorphonuclear leukocytes. The number of ingested bacteria was not significantly different among the strains, and the ingestion of the acapsular O139 mutants thus showed that the capsule does not play an antiphagocytic role. These data suggest that the capsule of V. cholerae O139 has a physiological function different from that of the ordinal hydrophilic capsule that is found in invasive bacteria such as Klebsiella pneumoniae. Received: 23 March 1998 / Accepted: 28 July 1998     

Biochemistry and structure of the glycan secreted by desiccation-tolerantNostoc commune (Cyanobacteria)

Summary Filaments of the desiccation-tolerant cyanobacteriumNostoc commune are embedded within, and distributed throughout, a dense glycan sheath. Analysis of the glycan of field materials and of pure cultures ofN. commune DRH 1 through light and electron microscopy, immunogold labelling and staining with dyes, revealed changes in the pattern of differentiation in glycan micro-structure, as well as localized shifts in pH, upon rehydration of desiccated field material. A Ca/Si rich external (pellicular) layer of the glycan acts as a physical barrier to epiphytic bacteria on the surface ofN. commune colonies. A purified fraction (>12 kDa) of an aqueous extract of the glycan from desiccated field material contained glucose, N-acetylglucosamine, glucosamine, mannose, and galactosamine with ratios of 3.11.410.10.06, respectively. Lipid soluble extracts ofN. commune contained trehalose and sucrose and the levels of both became undetectable following cell rehydration. Intracellular cyanobacterial trehalase was identified using immunoblotting and its synthesis was detected upon rehydration of desiccated field cultures. Elemental analysis of glycan extracts showed a flux in the concentrations of salts in the glycan matrix following rehydration of desiccated colonies. Water-stress proteins (Wsp; most abundant proteins in glycan), a water soluble UV-A/B-absorbing pigment, the lipid-soluble UV-protective pigment scytonemin (in both its oxidized and reduced forms), as well as two unidentified cyanobacterial glycoproteins (75 kDa and 110 kDa), were found within the glycan matrix. An unidentified 68 kDa protein, the second most abundant protein in aqueous extracts of the glycan, was isolated and its N-terminal sequence was determined as AFIFGTISPNNLSGTSGNSGIVGSA. Gene bank searches with this sequence identified significant homologies (35–45%) with various carbohydrate-modifying enzymes. The role of the glycan in the desiccation tolerance ofN. commune is discussed with respect to structure/function relationships.Abbreviations EPS extracellular polysaccharides - Wsp water-stress protein - SEM scanning electron microscopy - TEM transmission electron microscopy - EDX energy dispersive X-ray analysis - FPLC fast performance liquid chromatography - SDS-PAGE sodium dodecylsulfate polyacrylamide gel electrophoresis - TLC thin layer chromatography - UV ultra-violet radiation - UTEX University of Texas Culture Collection