Studies on hyaluronidase, chondroitin sulphatase, proteinase and phospholipase secreted by Candida species

Summary. We studied the ability of different Candida species to produce, at the same time, hyaluronidase, chondroitin sulphatase, proteinase, and phospholipase to assess whether they could be related to Candida pathogenicity. Only C. albicans was able to produce the four enzymes tested (73%) and was highly virulent to mice. Strains, that lack the capacity to produce one or more of the enzymes assayed, seemed less virulent or avirulent, similarly to the spontaneous hyaluronidase, chondroitin sulphatase, phospholipase and proteinase-deficient C. albicans strain FCF 14,1 which was non-pathogenic to mice. Among the other Candida species tested, none of them produced the four enzymes simultaneously, being less virulent in intravenously inoculated mice.
Zusammenfassung. Es wurde die Fähigkeit mehrerer Candida -Arten, gleichzeitig Hyaluronidase-, Chondroitinsulfatase-, Proteinase- und Phospholipase-Aktivität auszubilden, untersucht und deren Bedeutung als Candida -Pathogenitäts-merkmal bewertet. Nur C. albicans -Stämme waren in der Lage, die vier Enzyme zu bilden und waren für Mäuse hochvirulent. Stämme, welchen die Fähigkeit fehlte, eines oder mehrere dieser Enzyme zu produzieren, schienen weniger virulent oder avirulent zu sein, ähnlich wie der C. albicans -Stamm FCF 14,1, der spontan defizient für alle vier Enzyme war und der sich als nichtpathogen für Mäuse erwies. Von allen übrigen getesteten Candida -Arten produzierte keine gleichzeitig alle vier Enzyme, und diese erwiesen sich bei intravenöser Infektion als weniger virulent für Mäuse.     

解脲脲原体感染与女性生殖系统疾病的关系

解脲脲原体（Ureaplasma urealyticum，UU）是女性泌尿生殖系统感染的常见病原体之一，且近年来其感染呈增多趋势。本文就UU的致病物质、相关动物模型的建立、UU与各种女性生殖系统疾病的相关性研究等方面进行综述。旨在对女性感染UU实现早检查、早诊断、早治疗，以利改善预后。     

A genomic population genetics analysis of the pathogenic enterocyte effacement island in Escherichia coli: the search for the unit of selection

Comparative genomic analysis is a powerful tool for understanding the history and organization of complete genomes. The mathematical tools of population genetics combined with genomic analysis provide a powerful approach to dissect heterogeneities in genome evolution. This study presents a hierarchical analysis of the enterocyte and effacement island (35 kb), which is found in the enteropathogenic and enterohemorrhagic strains in Escherichia coli and in Citrobacter rodentium. The locus of enterocyte and effacement in E. coli is considered to be a clonal unit inside a clonal organism and is expected to evolve as a single unit. This analysis examines the clonal assumption by determining genetic diversity, GC content, and the substitution rates at the different functional levels of (i) the complete pathogenic island, (ii) the five operons in which the island is organized, and (iii) for each of the individual 41 genes that comprise the locus. We find that there is a conserved region that is composed of genes that belong to the type III secretion system and that may be products of horizontal transfer. A more diverse region is composed of genes for secreted proteins and genes that we infer to be original components of the E. coli genome. This genetic mosaic seems to be differentially affected by selection and mutation. Our results suggest that recombination and selection may be breaking this structure so that different elements are, at best, weakly coupled in their evolution. These observations suggest that the units of selection are not the complete island, but rather, much smaller units that comprise the island.     

The pathogenicity of Entamoeba histolytica is related to the capacity of evading innate immunity

The host and parasite factors that influence susceptibility to Entamoeba histolytica infection and disease are not well understood. Entamoeba histolytica pathogenicity has been considered by focusing principally on parasite rather than host factors. Thus, research has concentrated on explaining the molecular differences between pathogenic E. histolytica and non-pathogenic E. dispar. However, the amoeba molecules considered most important for host tissue destruction (amoebapore, galactose/N-acetyl galactosamine inhibitable lectin, and cysteine proteinases) are present in both pathogenic E. histolytica and non-pathogenic E. dispar. In addition, the genetic differences in pathogenicity among E. histolytica isolates are unlikely to completely explain the different outcomes of infection. Considering that the principal difference between pathogenic and non-pathogenic amoebas lies in their surface coats, we propose that pathogenicity of the amoebas is related to the composition and properties of the surface coat components (or pathogen-associated molecular patterns, PAMPs), and the ability of innate immune response to recognize these components and eliminate the parasite. According to this hypothesis, a key feature that may distinguish pathogenic (E. histolytica) from non-pathogenic (E. dispar) strains is whether or not they can overcome innate immune defences. A corollary of this hypothesis is that in susceptible individuals the PAMPs are either not recognized or they are recognized by a set of Toll-like receptors (TLRs) that leads to an inflammatory response. In both cases, the result is tissue damage. On the contrary, in resistant individuals the innate/inflammatory response, induced through the activation of a different set of TLRs, eliminates the parasite.     

Shigella interaction with intestinal epithelial cells determines the innate immune response in shigellosis

Shigellae are Gram-negative bacilli that cause bacillary dysentery in humans. This review summarizes current knowledge of Shigella pathogenesis and pathogenicity factors, invasion of epithelial cells, intracellular motility and cell-to-cell spreading, as well as components of the host cell involved in innate immune responses.     

Phosphorylation of<Emphasis Type="Italic">Helicobacter pylori CagA</Emphasis> in patients with gastric ulcer and gastritis

The effects ofHelicobacter pylori infection are strongly associated with chronic gastritis, gastric and duodenal ulcer, gastric cancer, and MALT lymphoma. The microorganism has been classified as a type I carcinogen by the World Health Organization. Varying clinical results fromH. pylori infection are believed due, in part, to differences in virulence among species. Thecag pathogenicity island is a complex of virulent genes and a coding region for the type IV phosphorylated secretion system. Through this system, many virulent gene products or proteins are phosphorylated into the host cells. This study demonstrated the positiveCagA- phosphorylation effect ofH. pylori in patients with chronic gastritis and benign gastric ulcer and revealed significantly different rates ofCagA phosphorylation between these two diseases (P < .05).     

Classification of Fungi in modern view

Fungi are a heterogeneous jumble coming together from three kingdoms of organisms. The True Fungi represent a kingdom of its own and are positioned closer to the Animalia than to the Plantae. At present the Fungi are divided into five Divisions. Species pathogenic for humans are found in the Divisions Zygomycota, Ascomycota and Basidiomycota. The Pneumocystidales are now classified in the Ascomycota. The Malasseziales are included in the Class Ustilaginomycetes. Essential characteristics for the classification of Fungi are derived from ultrastructure, chemistry, and more recently also from molecular biology of these organisms. None of these methods can stand for its own, all characteristics must be included.