Changes in gut bacterial communities in canaries infected by Macrorhabdus ornithogaster

Macrorhabdus ornithogaster is an opportunistic yeast that colonizes the gastric mucosa of many avian species. Until now, no studies have focused on the influence of a gastric infection on the balance of the intestinal microbiota of birds. In this study, 44 faecal samples from individual canaries, with and without M. ornithogaster infection, were analysed. The detection of the yeast was evaluated by 18S rRNA PCR. In order to evaluate the impact of the Macrorhabdus infection on the bacterial communities, culture-independent methods, by the use of amplicon-based sequencing as well as 16S rRNA-DGGE, were adopted. The different health status of animals affected the relative abundance of the main OTUs, with a greater diversification of the gut microbiota in healthy animals compared to the infected. In particular, Lactococcus, Pseudomonas, Acinetobacter, Lachnospiraceae, Propionibacterium and Weissella were found to be characteristic of uninfected animals (FDR?<?0.05), while Lactobacillus and Candidatus Arthromitus were characteristic of infected animals (FDR?<?0.05). Both these taxa have been reported as immunostimulatory, involved in immunological disorders. In infected animals the inferred metagenome assessed by PICRUST clearly showed a positive correlation between the presence of M. ornithogaster and KEGG genes related to ether lipid metabolism, already reported to be immunostimulatory by activation of macrophages and to play a pathophysiological role in several immunological disorders. Finally, our results show an interaction between infection of the digestive tract and intestinal microbiota of pet birds and provide insight into the changing of the complex enteric bacterial community.

• HIGHLIGHTS

• Macrorabdus ornithogaster is a gastric yeast that colonizes a wide range of birds.

• Differences were found between infected and healthy animals in gut microbiota.

• Candidatus Arthromitus was closely associated with infected birds.

• M. ornithogaster can affect intestinal microbiota composition of canaries.

     

Are transforming properties of the bovine papillomavirus E5 protein shared by E5 from high-risk human papillomavirus type 16?

The E5 proteins of bovine papillomavirus type 1 (BPV-1) and human papillomavirus type 16 (HPV-16) are small (44-83 amino acids), hydrophobic polypeptides that localize to membranes of the Golgi apparatus and endoplasmic reticulum, respectively. While the oncogenic properties of BPV-1 E5 have been characterized in detail, less is known about HPV-16 E5 due to its low expression in mammalian cells. Using codon-optimized HPV-16 E5 DNA, we have generated stable fibroblast cell lines that express equivalent levels of epitope-tagged BPV-1 and HPV-16 E5 proteins. In contrast to BPV-1 E5, HPV-16 E5 does not activate growth factor receptors, phosphoinositide 3-kinase or c-Src, and fails to induce focus formation, although it does promote anchorage-independent growth in soft agar. These variant activities are apparently unrelated to differences in intracellular localization of the E5 proteins since retargeting HPV-16 E5 to the Golgi apparatus does not induce focus formation.     

Abnormality of chromosome 16 and its phenotypic expression

An abnormality of chromosome 16 in which there is extra genetic material present on the short arm (46, XY, 16p+) has been identified. This chromosomal aberration was associated with multiple congenital anomalies, including mid-facial hypoplasia, arthrogryposis, and mental retardation. On the basis of the cytogenetic appearance and the phenotype of the patient, this may represent a partial 16 trisomy. Unlike most abnormalities of chromosome 16, this syndrome was compatible with life.     

细胞衰老与p16INK4a的转录调控

抑癌基因p16~(INK4a)可特异地抑制CDK4及CDK6,在抑制细胞生长、促进细胞衰老等方面发挥重要的生物学作用。由于p16~(INK4a)功能的重要性,近年来,针对p16~(INK4a)转录调控方面的研究取得了一系列进展,发现了一系列正性和负性调控元件和转录调控因子,如:E47、Id1、Jun B、Bmi-1、RREB等,为进一步认识细胞增殖规律以及衰老进程具有重要的理论意义。     

Significance of beta-catenin and pRB pathway components in malignant ovarian germ cell tumours: INK4A promoter CpG island methylation is associated with cell proliferation

To clarify the mechanisms underlying cell cycle promotion in malignant germ cell tumours of the ovary (MGCTOs), beta-catenin and components of the pRB pathway, cyclin D1 and p16, were analysed in relation to cell proliferation. Immunohistochemically, p16 protein was not expressed in a number of MGCTOs (9 of 42 tumours: 21.4%) and was associated with p16 gene (INK4A) promoter 5'-CpG islands methylation. Amplification of the cyclin D1 gene (CCND1) was detected in a small number of MGCTOs (5 of 42 tumours: 13.5%). Reduced expression of p16 due to promoter methylation correlated significantly with increased cell proliferation as evidenced by Ki-67 labelling index (p < 0.001) and mitotic index (p < 0.01). In some tumour types, nuclear localization of beta-catenin has been reported to be associated with beta-catenin gene (CTNNB1) mutation, cyclin D1 overexpression, and increased cell proliferation. Nuclear localization of beta-catenin, which was observed in MGCTOs other than dysgerminoma, was not associated with cyclin D1 expression and increased cell proliferation, but appeared to be related to tumour differentiation. Furthermore, CTNNB1 mutations were not detected in any of the MGCTOs examined. Our results suggest that reduced expression of p16 due to INK4A promoter methylation is one of the principal factors that promote cell proliferation in MGCTOs. Thus, p16 may be a novel target for gene therapies to treat MGCTOs.     

Townes-Brocks syndrome

Townes-Brocks syndrome (TBS) is an autosomal dominant disorder with multiple malformations and variable expression. Major findings include external ear anomalies, hearing loss, preaxial polydactyly and triphalangeal thumbs, imperforate anus, and renal malformations. Most patients with Townes-Brocks syndrome have normal intelligence, although mental retardation has been noted in a few.     

Human chromosome 16 conservation in primates

A study was made of the organization of the chromosome orthologous to HSA16 in primates using a panel of 8 BAC probes spanning human chromosome 16. The probes were used in FISH experiments on great apes and on representatives of the Old World monkeys, New World monkeys, and lemurs. The domestic cat was used as an outgroup. The results indicate that 16p and 16q were separate chromosomes in a primate ancestor. They fused in a Catarrhini ancestor giving rise to the present day form found in HSA, great apes, and Old World monkeys. Several rearrangements were found in New World monkeys.     

A fatal case of necrotizing sinusitis due to toxigenic Corynebacterium ulcerans

A 77-year-old farmer developed cough with sputum production, fever, bloody nasal discharge and a mass in his right maxillary sinus leading to necrotic ulceration of the sinus. Corynebacterium ulcerans, carrying the beta-phage for the diphtheria toxin and secreting the toxin, was detected microscopically and by culture from the sinusoidal and ulcer discharge. Despite immediate antimicrobial chemotherapy the patient died of pulmonary failure associated with the production of large amounts of very viscous sputum. Identification of the causative agent, pathophysiological aspects and risk factors of this unusal infection are discussed.