M6 Membrane Protein Plays an Essential Role in Drosophila Oogenesis

We had previously shown that the transmembrane glycoprotein M6a, a member of the proteolipid protein (PLP) family, regulates neurite/filopodium outgrowth, hence, M6a might be involved in neuronal remodeling and differentiation. In this work we focused on M6, the only PLP family member present in Drosophila, and ortholog to M6a. Unexpectedly, we found that decreased expression of M6 leads to female sterility. M6 is expressed in the membrane of the follicular epithelium in ovarioles throughout oogenesis. Phenotypes triggered by M6 downregulation in hypomorphic mutants included egg collapse and egg permeability, thus suggesting M6 involvement in eggshell biosynthesis. In addition, RNAi-mediated M6 knockdown targeted specifically to follicle cells induced an arrest of egg chamber development, revealing that M6 is essential in oogenesis. Interestingly, M6-associated phenotypes evidenced abnormal changes of the follicle cell shape and disrupted follicular epithelium in mid- and late-stage egg chambers. Therefore, we propose that M6 plays a role in follicular epithelium maintenance involving membrane cell remodeling during oogenesis in Drosophila

A Mouse Model of Post-Arthroplasty Staphylococcus aureus Joint Infection to Evaluate In Vivo the Efficacy of Antimicrobial Implant Coatings

Post-arthroplasty infections represent a devastating complication of total joint replacement surgery, resulting in multiple reoperations, prolonged antibiotic use, extended disability and worse clinical outcomes. As the number of arthroplasties in the U.S. will exceed 3.8 million surgeries per year by 2030, the number of post-arthroplasty infections is projected to increase to over 266,000 infections annually. The treatment of these infections will exhaust healthcare resources and dramatically increase medical costs.To evaluate novel preventative therapeutic strategies against post-arthroplasty infections, a mouse model was developed in which a bioluminescent Staphylococcus aureus strain was inoculated into a knee joint containing an orthopaedic implant and advanced in vivo imaging was used to measure the bacterial burden in real-time. Mice inoculated with 5x10(3) and 5x10(4) CFUs developed increased bacterial counts with marked swelling of the affected leg, consistent with an acute joint infection. In contrast, mice inoculated with 5x10(2) CFUs developed a low-grade infection, resembling a more chronic infection. Ex vivo bacterial counts highly correlated with in vivo bioluminescence signals and EGFP-neutrophil fluorescence of LysEGFP mice was used to measure the infection-induced inflammation. Furthermore, biofilm formation on the implants was visualized at 7 and 14 postoperative days by variable-pressure scanning electron microscopy (VP-SEM). Using this model, a minocycline/rifampin-impregnated bioresorbable polymer implant coating was effective in reducing the infection, decreasing inflammation and preventing biofilm formation.Taken together, this mouse model may represent an alternative pre-clinical screening tool to evaluate novel in vivo therapeutic strategies before studies in larger animals and in human subjects. Furthermore, the antibiotic-polymer implant coating evaluated in this study was clinically effective, suggesting the potential for this strategy as a therapeutic intervention to combat post-arthroplasty infections

Renewable energy from Cyanobacteria: energy production optimization by metabolic pathway engineering

The need to develop and improve sustainable energy resources is of eminent importance due to the finite nature of our fossil fuels. This review paper deals with a third generation renewable energy resource which does not compete with our food resources, cyanobacteria. We discuss the current state of the art in developing different types of bioenergy (ethanol, biodiesel, hydrogen, etc.) from cyanobacteria. The major important biochemical pathways in cyanobacteria are highlighted, and the possibility to influence these pathways to improve the production of specific types of energy forms the major part of this review

Uridylation and adenylation of RNAs

The posttranscriptional addition of nontemplated nucleotides to the 3′ ends of RNA molecules can have a significant impact on their stability and biological function. It has been recently discovered that nontemplated addition of uridine or adenosine to the 3′ ends of RNAs occurs in different organisms ranging from algae to humans, and on different kinds of RNAs, such as histone mRNAs, mRNA fragments, U6 snRNA, mature small RNAs and their precursors etc. These modifications may lead to different outcomes, such as increasing RNA decay, promoting or inhibiting RNA processing, or changing RNA activity. Growing pieces of evidence have revealed that such modifications can be RNA sequence-specific and subjected to temporal or spatial regulation in development. RNA tailing and its outcomes have been associated with human diseases such as cancer. Here, we review recent developments in RNA uridylation and adenylation and discuss the future prospects in this research area

Effects of nitrogen limitation and starvation on Chroococcidiopsis sp. (Chroococcales)

Chroococcidiopsis sp. cells from hot desert rock (Timna National Park, Israel) were grown in modified BG-11 medium which was either N-free or which contained different concentrations of nitrogen, provided as nitrate. The life cycle, ultrastructure and physiological activities of the cyanobacterium were investigated over a period of 4 months. No alterations were detected in cells grown in medium containing 250 or 125 μg N ml-1. In contrast, cells grown in medium with 62 μg N ml-1 or lacking nitrogen occurred only as isolated viable forms, after 3 months and 1 month of growth, respectively. In these cells a decrease in the content of cellular chlorophyll and phycocyanin paralleled undetectable O2 evolution and depressed O2 uptake. In addition, such isolated cells were characterized by a multilayered envelope, whereas, in the cytoplasm, vesiculated thylakoids and glycogen granules were observed. N-limited and N-starved cells recovered their cellular organization and physiological activities upon N repletion. These 'survival' cells had a spore-like form, and were functionally comparable to akinetes

Characterization of UHMWPE Wear Particles

Although most total joint prostheses remain stable for many years, a significant proportion experience loosening, with about 10% requiring revision 10 years after primary arthroplasty. It is generally accepted that osteolysis, among other causes, is initiated by the biological response to wear particles, which are released from ultra high molecular weight polyethylene acetabular liners and tibial trays. Wear particles up to 10 μm in size are predicted to be phagocytosed by resident macrophages and cause the release of inflammatory cytokines and chemokines, including tumor necrosis factor alpha (TNF-α), interleukin-1beta (IL-1β, IL-6, and IL-8. These cytokines stimulate the release of other mediators and the ensuing inflammatory cascade results in the formation of a periprosthetic granulomatous tissue reaction. Histopathological studies have revealed that these inflammatory cytokines facilitate osteoclastagenesis, which results in resorption of bone and a painfully loose implant. Revision surgery is currently the only option for the patient and surgeon