In vitro maturation, fertilization and early cleavage rates of bovine fetal oocytes

The in vitro developmental competence of oocytes harvested from 3 to 6 mm follicles from ovaries of 7.5 months to term fetuses and adult cows was compared. Cumulus oocyte complexes (COCs) were washed and placed in 200 microl droplets of maturation medium 199, supplemented with 10 microg/ml FSH, 10 microg/ml LH, 1.5 microg/ml estradiol, 75 microg/ml streptomycin, 100 IU/ml penicillin, 10 mM Hepes, and 10% fetal bovine serum (FBS) under oil and incubated for 24 h at 39 degrees C and 5% CO2. Matured oocytes were exposed to frozen-thawed TALP swim-up, heparin-capacitated sperm (20 h, 39 degrees C, 5% CO2). Presumptive zygotes were cultured in medium 199 containing 8 mg/ml BSA-V, 100 IU/ml penicillin G, 75 microg/ml streptomycin, and 10 mM Hepes (48 h, 39 degrees C, 5% CO2). Oocytes/embryos were fixed, stained with DAPI, and evaluated under fluorescent microscopy to assess maturation, fertilization, and subsequent embryonic development. There was a difference (P<0.05) between fetal and adult cow oocytes for in vitro maturation (IVM; 80.1% versus 92.0%), fertilization (69.3% versus 79.9%), and cleavage rates (36.7% versus 49.9%), respectively. Poor IVM, fertilization and embryonic development of fetal oocytes may be due to a higher incidence of blockage at germinal vesicle (GV) and metaphase-I (M-I) stage after IVM (12.0% versus 2.3% for fetal versus adult oocytes, respectively, P<0.05). Although the IVF results with fetal oocytes are poorer than with adult cow oocytes, they were still high enough to be considered for use in research and when death of the dam and/or fetus is pre-mature or sudden.     

Binding of transition metal ions [cobalt, copper, nickel and zinc] with furanyl-, thiophenyl-, pyrrolyl-, salicylyl- and pyridyl-derived cephalexins as potent antibacterial agents

A method is described for the preparation of novel cephalexin-derived furanyl-, thiophenyl-, pyrrolyl-, salicylyl- and pyridyl-containing compounds showing potent antibacterial activity. The binding of these newly synthesized antibacterial agents with metal ions such as cobalt(II), copper(II), nickel(II) and zinc(II) has been studied and their inhibitory properties against various bacterial species such as Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Klebsiella pneumoniae are also reported. These results suggest that metal ions to possess an important role in the designing of metal-based antibacterials and that such complexes are more effective against infectious diseases compared to the uncomplexed drugs.     

Composition,acquisition, and distribution of the Vi exopolysaccharide-encoding Salmonella enterica pathogenicity island SPI-7

Vi capsular polysaccharide production is encoded by the viaB locus, which has a limited distribution in Salmonella enterica serovars. In S. enterica serovar Typhi, viaB is encoded on a 134-kb pathogenicity island known as SPI-7 that is located between partially duplicated tRNA(pheU) sites. Functional and bioinformatic analysis suggests that SPI-7 has a mosaic structure and may have evolved as a consequence of several independent insertion events. Analysis of viaB-associated DNA in Vi-positive S. enterica serovar Paratyphi C and S. enterica serovar Dublin isolates revealed the presence of similar SPI-7 islands. In S. enterica serovars Paratyphi C and Dublin, the SopE bacteriophage and a 15-kb fragment adjacent to the intact tRNA(pheU) site were absent. In S. enterica serovar Paratyphi C only, a region encoding a type IV pilus involved in the adherence of S. enterica serovar Typhi to host cells was missing. The remainder of the SPI-7 islands investigated exhibited over 99% DNA sequence identity in the three serovars. Of 30 other Salmonella serovars examined, 24 contained no insertions at the equivalent tRNA(pheU) site, 2 had a 3.7-kb insertion, and 4 showed sequence variation at the tRNA(pheU)-phoN junction, which was not analyzed further. Sequence analysis of the SPI-7 region from S. enterica serovar Typhi strain CT18 revealed significant synteny with clusters of genes from a variety of saprophytic bacteria and phytobacteria, including Pseudomonas aeruginosa and Xanthomonas axonopodis pv. citri. This analysis suggested that SPI-7 may be a mobile element, such as a conjugative transposon or an integrated plasmid remnant.     

Unsymmetrical 1,1'-disubstituted ferrocenes: synthesis of Co(ii), Cu(ii), Ni(ii) and Zn(ii) chelates of ferrocenyl -1-thiadiazolo-1'-tetrazole, -1-thiadiazolo-1'-triazole and -1-tetrazolo-1'-triazole with antimicrobial properties

Condensation reactions of 1,1'-diacetylferrocene with different heteroaromatic amines such as, 2-amino-1,3,4-thiadiazole, 5-aminotetrazole and 3-amino-1,2,4-triazole to form unsymmetrically 1,1'-disubstituted ferrocenes have been studied. The obtained compounds have been further investigated for their liganding and biological properties upon chelation with Co(II), Cu(II), Ni(II) and Zn(II) metal ions. The synthesized compounds have been characterized by physical, spectral and analytical data and have been screened against pathogenic bacterial strains e.g., Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus, showing moderate activity as antibacterials in vitro.     

Transition metal acetylsalicylates and their anti-inflammatory activity

Mononuclear and binuclear transition metal [Co(II), Cu(II), Ni(II) and Zn(II)] acetylsalicylates of the type [M(L)2], [M(L)2Cl2] and [(M)2(L)4] have been prepared and characterized on the basis of their physical, spectral and analytical data. The complexes have been investigated in an in vivo animal model for anti-inflammatory activity and show a better effect and a more potent action than acetylsalicylic acid.     

Evidence for frequent reinfection with human immunodeficiency virus type 1 of a different subtype

A major premise underlying current human immunodeficiency virus type 1 (HIV-1) vaccine approaches is that preexisting HIV-1-specific immunity will block or reduce infection. However, the recent identification of several cases of HIV-1 reinfection suggests that the specific immune response generated for chronic HIV-1 infection may not be adequate to protect against infection by a second HIV-1 strain. It has been unclear, though, whether these individuals are representative of the global epidemic or are rare cases. Here we show that in a population of high-risk women, HIV-1 reinfection occurs almost as commonly as first infections. The study was designed to detect cases of reinfection by HIV-1 of a different subtype and thus captured cases where there was considerable diversity between the first and second strain. In each case, the second virus emerged approximately 1 year after the first infection, and in two cases, it emerged when viral levels were high, suggesting that a well-established HIV-1 infection may provide little benefit in terms of immunizing against reinfection, at least by more-divergent HIV-1 variants. Our findings indicate an urgent need for studies of larger cohorts to determine the incidence and timing of both intersubtype and intrasubtype reinfection.     

Turning cells red: signal transduction mediated by erythropoietin

Erythropoietin (EPO) is the crucial cytokine regulator of red blood-cell production. Since the discovery of EPO in 1985 and the isolation of its cognate receptor four years later, there has been significant interest in understanding the unique ability of this ligand-receptor pair to promote erythroid mitogenesis, survival and differentiation. The development of knockout mice has elucidated the precise role of the ligand, receptor and downstream players in murine erythroid development. In this review, we summarize EPO-mediated signaling pathways and examine their significance in vivo.     

Metal binding and antibacterial activity of ciprofloxacin complexes

Four novel cobalt(II), copper(II), nickel(II) and zinc(II) complexes of the fluoroquinolone antibiotic ciprofloxacin have been prepared. The compounds were characterized by IR, UV-Visible, molar conductivity and elemental analyses. In all of the complexes, the drug ligand, ciprofloxacin (CFL) was coordinated through two carbonyl oxygen atoms. Octahedral and square-planar geometries have been proposed for the cobalt(II), nickel(II) and zinc(II), and copper(II) complexes, respectively. In vitro tests of susceptibility to these metal complexes showed stronger activity than that of ciprofloxacin against Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae and Bacillus dysenteriae.     

Antibacterial cobalt (II), copper (II), nickel (II) and zinc (II) complexes of mercaptothiadiazole--derived furanyl, thienyl, pyrrolyl, salicylyl and pyridinyl Schiff bases

A series of Co (II), Cu (II), Ni (II) and Zn (II) complexes of mercaptothiadiazole-derived furanyl, thienyl, pyrrorlyl, salicylyl and pyridinyl Schiff bases were synthesized, characterized and screened for their in vitro antibacterial activity against four Gram-negative, Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi and Shigella fexneri, and two Gram-positive; Bacillus subtilis and Staphylococcus aureous bacterial strains. The results of these studies show the metal complexes to be more antibacterial as compared to the prepared un-complexed Schiff bases.