Amplified centrosomes may underlie aggressive disease course in pancreatic ductal adenocarcinoma

Centrosome amplification (CA), the presence of centrosomes that are abnormally numerous or enlarged, is a well-established driver of tumor initiation and progression associated with poor prognosis across a diversity of malignancies. Pancreatic ductal adenocarcinoma (PDAC) carries one of the most dismal prognoses of all cancer types. A majority of these tumors are characterized by numerical and structural centrosomal aberrations, but it is unknown how CA contributes to the disease and patient outcomes. In this study, we sought to determine whether CA was associated with worse clinical outcomes, poor prognostic indicators, markers of epithelial-mesenchymal transition (EMT), and ethnicity in PDAC. We also evaluated whether CA could precipitate more aggressive phenotypes in a panel of cultured PDAC cell lines. Using publicly available microarray data, we found that increased expression of genes whose dysregulation promotes CA was associated with worse overall survival and increased EMT marker expression in PDAC. Quantitative analysis of centrosomal profiles in PDAC cell lines and tissue sections uncovered varying levels of CA, and the expression of CA markers was associated with the expression of EMT markers. We induced CA in PDAC cells and found that CA empowered them with enhanced invasive and migratory capabilities. In addition, we discovered that PDACs from African American (AA) patients exhibited a greater extent of both numerical and structural CA than PDACs from European American (EA) patients. Taken together, these findings suggest that CA may fuel a more aggressive disease course in PDAC patients.     

Use of critically important antimicrobial classes early in life may adversely impact bacterial resistance profiles during adult years: potential co-selection for plasmid-borne fluoroquinolone and macrolide resistance via extended-spectrum beta-lactam use in dairy cattle

The transfer of antimicrobial resistance genes commonly occurs via vertical and horizontal gene transfer, as such genes are often found on the same mobile genetic element. This occurrence can lead to the co-selection of resistance to antimicrobials without their application. Dairy cattle located in the south-western United States were enrolled in a matched-pair longitudinal study to evaluate the effects of a two-dose ceftiofur treatment for metritis on levels of third-generation cephalosporin resistance among faecal Escherichia coli temporally. Escherichia coli chosen for further investigation were isolated on selective media, harboured extended-spectrum beta-lactam, fluoroquinolone and macrolide resistance genes. This combination has previously been unreported; importantly, it included genes encoding for resistance to antibiotics that can only be used in dairy cattle less than 20 months of age. Fluoroquinolones, macrolides and third and higher generation cephalosporins are considered critically important and highest priority for human medicine by the World Health Organization.     

Bacteria–bacteria interactions within the microbiota of the ancestral metazoan Hydra contribute to fungal resistance

Epithelial surfaces of most animals are colonized by diverse microbial communities. Although it is generally agreed that commensal bacteria can serve beneficial functions, the processes involved are poorly understood. Here we report that in the basal metazoan Hydra, ectodermal epithelial cells are covered with a multilayered glycocalyx that provides a habitat for a distinctive microbial community. Removing this epithelial microbiota results in lethal infection by the filamentous fungus Fusarium sp. Restoring the complex microbiota in gnotobiotic polyps prevents pathogen infection. Although mono-associations with distinct members of the microbiota fail to provide full protection, additive and synergistic interactions of commensal bacteria are contributing to full fungal resistance. Our results highlight the importance of resident microbiota diversity as a protective factor against pathogen infections. Besides revealing insights into the in vivo function of commensal microbes in Hydra, our findings indicate that interactions among commensal bacteria are essential to inhibit pathogen infection.     

Presence of diguanosine tri, tetra-, and pentaphosphates in commercial samples of GTP and guanosine 5'-tetraphosphate

Commercial samples of GTP and guanosine 5'-tetraphosphate were analyzed, with or without previous treatment with alkaline phosphatase, by high-pressure liquid chromatography on a Hypersil ODS column. They showed the presence of diguanosine 5',5"'-Pl,Pn-tri, tetra-, and pentaphosphates in varying amounts depending on the sample, but usually in proportions of around 0.3%.     

Species-specific sperm adhesion in sea urchins. A quantitative investigation of bindin- mediated egg agglutination

Bindin, a protein component of the acrosomal vesicle of sea urchin sperm, has been isolated from Arbacia punctulata and strongylocentrous purpuratus. Using this isolated bindin, we have devised a quantitative assay for bindin-mediated egg agglutination and compared the agglutination of bindin eggs from A. puntulata and S. purpuratus. Bindin- mediated agglutination is species –specific in both species, although a measurable degree of heterotypic interaction is observed. Homotypic bindin-egg interactions differ significantly from heterotypic interactions both in the extent of agglutination and the size of the resulting aggregates. We also provide direct evidence that bindin particles agglutinate eggs by adhering to the surfaces of adjacent eggs. Although the A. punctulata bindin preparation displays the same functional properties and consists of one major polypeptide of the same apparent molecular weight as S. purpuratus bindin, its morphology is very different. Unlike the spherical aggregates observed with S. purpuratus bindin, A punctulata bindin exists as lamellar vesicles and binds significant amounts of phospholipids and Triton X-100, suggesting that it may be tightly associated with the acrosomal membrane. Having defined a number of the basic parameters of bindin-mediated agglutination, we examined the effect of a number of saccharides and glycopeptides on bindin-mediated egg agglutination. Carbohydrate-containing components derived from the egg cell surface by proteolysis were found to inhibit bindin-mediated egg agglutination at low concentrations, but this inhibition is not species specific.     

Isolation, characterization, and amino acid sequence of a ubiquitin-like protein from insect eggs

A protein with a primary structure identical to that of human and bovine ubiquitin has been purified from insect eggs. The isolation, secondary structure, and amino acid sequence of this ubiquitin-like protein are reported. The sequence was determined by automatic Edman degradation of the intact molecule as well as by the manual sequence analysis of the enzymatic cleavage products. The polypeptide has 74 amino acid residues and internal homology regions. Interactions of the protein with peptides results in protective effects against proteolysis. This paper reports for the first time the presence of the ubiquitin molecule in invertebrates.