Histopathology of retained bovine fetal membranes

Placentomes were obtained from 20 cows with retained placenta (9 following normal birth, 5 after abortion and 6 with dystocia), and this material was examined by light microscopy. Histologic changes that were consistently seen in placentomes of cows with retained placenta after normal birth included vascular changes (edema, thrombosis and vasculitis) and the presence of numerous clumps of bacterialcolonies in the connective tissue of the caruncles and cotyledons. Only a few binucleate cells were seen in these cases. In placentomes obtained from cows with retained placenta after abortion, there were instances of focal necrosis of the fetal villi and the presence of variable numbers of binucleate cells. Vascular changes and numerous clumps of bacterial colonies in the caruncles and cotyledons were also noted. The changes in placentomes obtained from cows with retained placenta and dystocia included the presence of numerous binucleate cells, infiltration of polymorphonuclear cells in the connective tissue of both the fetal and maternal villi, vascular changes, and the presence of extensive necrosis and numerous clumps of bacterial colonies. Significant differences (P < 0.05) were encountered in the number of binucleate cells in the various groups. Binucleate cells appear to be involved in the process of placental separation in cows with retained placenta.     

Effect of high fluoride intake on haematological aspects of the mouse.

The effect of feeding adult Swiss albino mice of both sexes a diet supplemented with 0, 125, 250 and 500 parts/10(6) of fluoride for four and eight week periods on haemoglobin concentration (Hb), packed cell volume (PCV) and mean corpuscular haemoglobin concentration (MCHC) was investigated. Values of the three parameters were significantly lowered at both periods in the treated groups as compared with the controls. The extent of reduction in these values was, in general, dependent on the dose of supplemented dietary fluoride. Clinical symptoms were not observed before the end of the sixth week. However, appearance of the symptoms did not change the trend of variations in Hb, PCV and MCHC values. The reduced values could be the result of lowered haemoglobin synthesis and erythropoiesis. It was suggested that these haematological indices could serve to detect preclinical effects of high fluoride intake with an added dose of as low as 125 parts/10(6), or even less, for a period of four weeks or probably earlier.     

Synthesis,Design, and Biological Evaluation of Novel Diethylphenylcarbamothioylphosphonate

Russian Journal of Bioorganic Chemistry - The aim of this work was to synthesize a diethyl phenylcarbamothioyl phosphonate (EThmP) and evaluate its biological activities. ThmP has been prepared...     

Mapping the microtubule binding regions of calponin

The smooth muscle basic calponin interacts with F-actin and inhibits the actomyosin ATPase in a calmodulin or phosphorylation modulated manner. It also binds in vitro to microtubules and its acidic isoform, present in nonmuscle cells, and co-localizes with microfilaments and microtubules in cultured neurons. To assess the physiological significance and the molecular basis of the calponin-microtubule interaction, we have first studied the solution binding of recombinant acidic calponin to microtubules using quantitative cosedimentation analyses. We have also characterized, for the first time, the ability of both calponin isoforms to induce the inhibition of the microtubule-stimulated ATPase activity of the cytoskeletal, kinesin-related nonclaret dysjunctional motor protein (ncd) and the abolition of this effect by calcium calmodulin. This property makes calponin a potent inhibitor of all filament-activated motor ATPases and, therefore, a potential regulatory factor of many motor-based biological events. By combining the enzymatic measurements of the ncd-microtubules system with various in vitro binding assays employing proteolytic, recombinant and synthetic fragments of basic calponin, we further unambiguously identified the interaction of microtubules at two distinct calponin sites. One is inhibitory and resides in the segment 145-182, which also binds F-actin and calmodulin. The other one is noninhibitory, specific for microtubules, and is located on the COOH-terminal repeat-containing region 183-292. Finally, quantitative fluorescence studies of the binding of basic calponin to the skeletal pyrenyl F-actin in the presence of microtubules did not reveal a noticeable competition between the two sets of filaments for calponin. This result implies that calponin undergoes a concomitant binding to both F-actin and microtubules by interaction at the former site with actin and at the second site with microtubules. Thus, in the living cells, calponin could potentially behave as a cross-linking protein between the two major cytoskeletal filaments.     

Activation of a dimeric metabotropic glutamate receptor by intersubunit rearrangement

Although many G protein-coupled receptors (GPCRs) can form dimers, a possible role of this phenomenon in their activation remains elusive. A recent and exciting proposal is that a dynamic intersubunit interplay may contribute to GPCR activation. Here, we examined this possibility using dimeric metabotropic glutamate receptors (mGluRs). We first developed a system to perfectly control their subunit composition and show that mGluR dimers do not form larger oligomers. We then examined an mGluR dimer containing one subunit in which the extracellular agonist-binding domain was uncoupled from the G protein-activating transmembrane domain. Despite this uncoupling in one protomer, agonist stimulation resulted in symmetric activation of either transmembrane domain in the dimer with the same efficiency. This, plus other data, can only be explained by an intersubunit rearrangement as the activation mechanism. Although well established for other types of receptors such as tyrosine kinase and guanylate cyclase receptors, this is the first clear demonstration that such a mechanism may also apply to GPCRs.     

Genotypic and Phenotypic Profiles of Enterotoxigenic <Emphasis Type="Italic">Escherichia coli</Emphasis> Associated with Acute Diarrhea in Tunis,Tunisia

No past studies of acute diarrhea in Tunisia have examined the phenotypic and genotypic profiles of enterotoxigenic Escherichia coli (ETEC) isolates. We determined 65 ETEC isolates derived from a total of 327 E. coli isolates collected from a previous study (acute diarrheal and healthy persons, children and adults n = 214) and 32 E. coli isolates derived from an acute diarrheal outbreak in Kabaria-Ennour city, Tunis. All E. coli isolates were screened by polymerase chain reaction (PCR) for ETEC virulence genes: sta (heat-stable toxin gene) and elt (heat-labile toxin gene). Seventy-two percent (47 of 65) of ETEC strains expressed the sta gene only, 21.5% (14 of 65) expressed the elt gene and 6.1% (4 of 65) expressed both genes. For the outbreak isolates, the elt gene was predominant (10 isolates out of 14). Ganylioside GM1 enzyme-linked immunosorbent assay (GM1-ELISA) was used to validate the PCR results and this was confirmed by dot blot assay. The same results were obtained. The most common colonization factors (CFs) were CFA/I (44.6%) and coli surface antigen 6 (CS6) (11%), and 44.6% of the isolates showed no association with either CFAs. Resistance of ETEC isolates to tetracycline (38.5%), streptomycin (26%), and beta-lactam agents (ticarcillin 26%, amoxicillin 24.6%, cephalotin 21.5%) was common. Regarding serotypes, the majority of ETEC isolates serotyped as O86:H(-) (n = 16), O128:H2 (n = 11), and O127:H21 (n = 10). Other serotypes found were O111:H(-) (n = 6) and O126: H(-) (n = 5). DNA macrorestriction fragment analysis by pulsed-field gel electrophoresis (PFGE) using the XbaI enzyme was conducted to investigate the epidemiological clonal relationship among ETEC isolates. Major patterns were identified among which some of outbreak ETEC isolates belonged. These data suggest that a proportion of acute diarrhea in Tunis represents the confluence of small epidemics by clonality-related ETEC isolates that are transiently introduced or that persist in our community.     

Anaerobic co-digestion of olive mill wastewater with olive mill solid waste in a tubular digester at mesophilic temperature

Anaerobic co-digestion is a well established process for treating many types of organic wastes, both solid and liquid. In this study we have investigated, on a laboratory scale, the anaerobic co-digestion of olive mill wastewater (OMW) with olive mill solid waste (OMSW) using semi-continuous, feeding, tubular digesters operated at mesophilic temperatures. Each digester was fed with an influent, composed of OMW and OMSW, at an organic loading rate (OLR) varying between 0.67 and 6.67 g COD/l/d. The hydraulic retention times (HRT) were 12, 24 and 36 days. The TCOD concentrations of OMW used as the main substrate were 24, 56 and 80 g COD/l; the amount of the dry OMSW used as a co-substrate was fixed to approximately 56 g/l of OMW. The results indicated that the best methane production was about 0.95 l/l/day obtained at an OLR = 4.67 g COD/l/d, corresponding to influent TCOD = 56 g COD/l at an HRT = 12d. In contrast, the maximum TCOD removal efficiency (89%) was achieved at an OLR = 0.67 g COD/l/d, corresponding to influent TCOD = 24 g COD/l at an HRT = 36 d. Moreover, the inhibition of biogas production was observed at the highest OLR studied.     

Isolation and Characterization of Moderately Halophilic Bacteria from Tunisian Solar Saltern

Bacterial screenings from solar saltern in Sfax (Tunisia) lead to the isolation of 40 moderately halophilic bacteria which were able to grow optimally in media with 5–15% of salt. These isolates were phylogenetically characterized using 16S rRNA gene sequencing. Two groups were identified including 36 strains of Gamma-Proteobacteria (90%) and 4 strains of Firmicutes (10%). The Gamma-Proteobacteria group consisted of several subgroups of the Halomonadaceae (52.5%), the Vibrionaceae (15%), the Alteromonadaceae (10%), the Idiomarinaceae (7.5%), and the Alcanivoracaceae (5%). Moreover, three novel species: 183ZD08, 191ZA02, and 191ZA09 were found, show <97% sequence similarity of the 16S rRNA sequences while compared to previously published cultivated species. Most of these strains (70%) were able to produce hydrolases: amylases, proteases, phosphatases, and DNAases. Over the isolates, 60% produced phosphatases, 15.0% proteases, 12.5% amylases and DNAases equally. This study showed that the solar saltern of Sfax is an optimal environment for halophilic bacterial growth, where diverse viable bacterial communities are available and may have many industrial applications.     

Sinorhizobium americanum symbiovar mediterranense is a predominant symbiont that nodulates and fixes nitrogen with common bean (Phaseolus vulgaris L.) in a Northern Tunisian field

A total of 40 symbiotic bacterial strains isolated from root nodules of common bean grown in a soil located in the north of Tunisia were characterized by PCR-RFLP of the 16S rRNA genes. Six different ribotypes were revealed. Nine representative isolates were submitted to phylogenetic analyses of rrs, recA, atpD, dnaK, nifH and nodA genes. The strains 23C40 and 23C95 representing the most abundant ribotype were closely related to Sinorhizobium americanum CFNEI 156(T). S. americanum was isolated from Acacia spp. in Mexico, but this is the first time that this species is reported among natural populations of rhizobia nodulating common bean. These isolates nodulated and fixed nitrogen with this crop and harbored the symbiotic genes of the symbiovar mediterranense. The strains 23C2 and 23C55 were close to Rhizobium gallicum R602sp(T) but formed a well separated clade and may probably constitute a new species. The sequence similarities with R. gallicum type strain were 98.7% (rrs), 96.6% (recA), 95.8% (atpD) and 93.4% (dnaK). The remaining isolates were, respectively, affiliated to R. gallicum, E. meliloti, Rhizobium giardinii and Rhizobium radiobacter. However, some of them failed to re-nodulate their original host but promoted root growth.