Factors Prior to Dry Period Associated with High and Low Levels of Cow Milk Somatic Cell Counts in Next Lactation

Data from a randomized controlled field study of selective dry cow therapy were used in which 686 cows had been allocated to 2 control groups (sampling only or placebo) or 2 therapy groups. Possible factors from previous lactation were assessed in determining their association with the probability of ‘failure’, designated as a cow milk somatic cell count (CMSCC) of greater than 399000 per ml in geometric mean of several measurements during subsequent lactation. Success cows were those with a CMSCC of less than 200000 per ml. For our analyses, this targeted 187 success cows and 186 failure cows. Therapy was given as a total dose of 400000 IU penicillin and 100 mg neomycin per infected quarter as dry cow preparation once, or as a lactation formula with a total dose of 1.2 million IU penicillin and 1200 mg dihydrostreptomycin per infected quarter during a 1-week period. Significant factors in the predictive model for success included therapy, low level of CMSCC (geometric mean of the 3 last tests) in previous lactation, low level of CMSCC (weighted by daily milk yield mean) in the herd, young cows, and not having had a case of treatment for chronic clinical mastitis. Additional information on the probability of failure in treated and untreated cows can be predicted by number of quarters infected with Staphylococcus aureus approximately 1.5 months before drying off. The models derived are considered for use as tools in selective treatment and culling decisions.     

Isolation and molecular characterization of theSinorhizobium meliloti bet locus encoding glycine betaine biosynthesis

To cope with osmotic stress,Sinorhizobium meliloti accumulates organic compatible solutes such as glutamate, trehalose, N-acetylglutaminylglutamine amide, and the most potent osmoprotectant glycine betaine. In order to study the regulation of the glycine betaine biosynthetic pathway, a genetic and molecular analysis was performed. We have selected a Tn5 mutant ofS. meliloti which was deficient in choline dehydrogenase activity. The mutation was complemented using a genomic bank ofS. meliloti. Subcloning and DNA sequencing of a 8-6 kb region from the complemented plasmid showed four open reading frames with an original structural organization of thebet locus compared to that described inE. coli. (i) ThebetB and thebetA genes which encode a glycine betaine aldehyde dehydrogenase, and a choline dehydrogenase, respectively, are separated from thebetI gene (regulatory protein) by an additional gene namedbetC. The BetC protein shares about 30% identity with various sulphatases and is involved in the conversion of choline-O-sulphate into choline. Choline-O-sulphate is used as an osmoprotectant, or as a carbon or sulphur source and this utilization is dependent on a functionalbet locus. (ii) No sequence homologous tobetT (encoding a high-affinity choline transport system inE. coli) was found in the vicinity of thebet locus. (iii) ThebetB and thebetA genes, as well as thebetI and thebetC genes are, respectively, separated by 211 and 167 bp sequences containing inverted repeats. Southern blot analysis indicated that thebet locus is located on the chromosome, and not on the megaplasmids.     

The Functional Roles of the MDM2 Splice Variants P2-MDM2-10 and MDM2-∆5 in Breast Cancer Cells

BACKGROUND: MDM2 is a negative regulator of p53 and is upregulated in numerous human cancers. While different MDM2 splice variants have been observed in both normal tissues and malignant cells, their functions are poorly understood. METHODS: We evaluated the effect of MDM2 splice variants by overexpression in MCF-7 cells and analyses of expression of downstream genes (qPCR and Western blot), subcellular localization (immunofluorescence), cell cycle assays (Nucleocounter3000), apoptosis analysis (Annexin V detection), and induction of senescence (β-galactosidase analysis). RESULTS: In a screen for MDM2 splice variants in MCF-7 breast cancer cells, extended with data from healthy leukocytes, we found P2-MDM2-10 and MDM2-Δ5 to be the splice variants expressed at highest levels. Contrasting MDM2 full-length protein, we found normal tissue expression levels of P2-MDM2-10 and MDM2-Δ5 to be highest in individuals harboring the promoter SNP309TT genotype. While we detected no protein product coded for by MDM2-Δ5, the P2-MDM2-10 variant generated a protein markedly more stable than MDM2-FL. Both splice variants were significantly upregulated in stressed cells (P = 4.3 × 10^?4 and P = 7.1 × 10^?4, respectively). Notably, chemotherapy treatment and overexpression of P2-MDM2-10 or MDM2-Δ5 both lead to increased mRNA levels of the endogenous MDM2-FL (P = .039 and P = .070, respectively) but also the proapoptotic gene PUMA (P = .010 and P = .033, respectively), accompanied by induction of apoptosis and repression of senescence. CONCLUSION: We found P2-MDM2-10 and MDM2-Δ5 to have distinct biological functions in breast cancer cells. GENERAL SIGNIFICANCE: Alternative splicing may influence the oncogenic effects of the MDM2 gene.     

Species richness in boreal swamp forests of SE Norway: The role of surface microtopography

Question: What is the relative importance of environmental gradients and surface microtopography (variation in vertical level within sampling units) for fine‐scale plant species richness in Picea abies swamp forests? Location: 11 swamp forests in SE Norway. Methods: We recorded species richness (number of species of vascular plants, mosses, Sphagnum and hepatics), depth to water table, soil base status and vertical range (microtopographic relief) in 2400 microplots, (each 1/16 m²), in 150 1‐m² plots in the 11 swamp forests. Relationships between species richness and environmental predictors were modelled by GLMM. Results: Moss and hepatic species richness increased with increasing microtopographic relief, most strongly for wet acid sites, in which similar trends were also found for Sphagnum. Relief was a poor predictor of vascular plant species richness. Conclusions: Microtopographic relief is a good predictor of local species richness in Picea abies swamp forests, partly because larger vertical variability means higher within‐plot habitat diversity with respect to the wet‐dry gradient, and partly because qualitatively new microhabitats associated with steep slopes are added in drier sites. The relationship between species richness and microtopographic relief is context dependent, differing in complex ways among species groups and among sites with different environmental conditions.     

Aerobic fermentation of D-glucose by an evolved cytochrome oxidase-deficient Escherichia coli strain

Fermentation of glucose to D-lactic acid under aerobic growth conditions by an evolved Escherichia coli mutant deficient in three terminal oxidases is reported in this work. Cytochrome oxidases (cydAB, cyoABCD, and cbdAB) were removed from the E. coli K12 MG1655 genome, resulting in the ECOM3 (E. coli cytochrome oxidase mutant) strain. Removal of cytochrome oxidases reduced the oxygen uptake rate of the knockout strain by nearly 85%. Moreover, the knockout strain was initially incapable of growing on M9 minimal medium. After the ECOM3 strain was subjected to adaptive evolution on glucose M9 medium for 60 days, a growth rate equivalent to that of anaerobic wild-type E. coli was achieved. Our findings demonstrate that three independently adaptively evolved ECOM3 populations acquired different phenotypes: one produced lactate as a sole fermentation product, while the other two strains exhibited a mixed-acid fermentation under oxic growth conditions with lactate remaining as the major product. The homofermenting strain showed a D-lactate yield of 0.8 g/g from glucose. Gene expression and in silico model-based analyses were employed to identify perturbed pathways and explain phenotypic behavior. Significant upregulation of ygiN and sodAB explains the remaining oxygen uptake that was observed in evolved ECOM3 strains. E. coli strains produced in this study showed the ability to produce lactate as a fermentation product from glucose and to undergo mixed-acid fermentation during aerobic growth.     

Determination of PCR efficiency in chelex-100 purified clinical samples and comparison of real-time quantitative PCR and conventional PCR for detection of Chlamydia pneumoniae

Background  

Chlamydia pneumoniae infection has been detected by serological methods, but PCR is gaining more interest. A number of different PCR assays have been developed and some are used in combination with serology for diagnosis. Real-time PCR could be an attractive new PCR method; therefore it must be evaluated and compared to conventional PCR methods.     

Studies directed toward the asialoglycoprotein receptor mediated delivery of 5-fluoro-2′-deoxyuridine for hepatocellular carcinoma

The anticancer nucleoside 5-fluoro 2′-deoxyuridine-5′-phosphate (5-FdU-P) was attached via an amide chain linker to a triantennary GalNAc cluster as a means to deliver the drug to hepatic cells that recognize the amino sugar units.     

Mycetophilidae (Diptera), an insect group vulnerable to forestry practices? A comparison of clearcut,managed and semi-natural spruce forests in southern Norway

The mycetophilid fauna and environmental variables were studied at 15 sites within a spruce forest in southern Norway. There were five replications of each of the following categories: semi-natural forests, clearcuts, and managed forests (clearcut 70–120 years ago). Clearcutting seems to induce a long lasting effect on the Mycetophilidae fauna. The semi-natural forests were more speciesrich and contained more potentially rare species than the two other categories. Even though managed forests and clearcuts differed in faunal composition, their species richness was not significantly different. Continuity is probably a main factor for maintaining the diversity of Mycetophilidae species. Lumping the 15 sites together, the number of species was strongly correlated with the (temporal) continuity of tree cover and substrates, which may reflect an increased diversity of fungal habitats both in dead wood and on the ground. The degree of continuity was recognized by means of indicator species of fungi, lichen and vascular plants. The amount of dead wood was correlated with the species diversity, but was probably dependent on the continuity factor, since clearcuts with much dead wood had relatively fewer species.Important elements in a strategy for conservation of the diversity of mycetophilid species seem to be: (i) to identify and protect the remnant patches of forests with long continuity, (ii) as far as possible, to practice timber harvesting in earlier clearcut forests instead of semi-natural forests.     

Cutting edge: molecular cloning of a killer cell Ig-like receptor in the mouse and rat

We report the molecular cloning of a KIR3DL1 receptor in the mouse and the rat, between 37.4 and 45.4% identical with primate killer cell Ig-like receptors (KIRs/CD158). Both mouse and rat molecules contain a pair of immunoreceptor tyrosine-based inhibition motifs in their cytoplasmic regions, suggesting an inhibitory function. Southern blot analysis indicated a single KIR gene in the rat, whereas the mouse genome contains more than one KIR-related element. The rat Kir3dl1 locus was mapped to the leukocyte receptor gene complex on chromosome 1, whereas mouse Kir3dl1 was localized to the X chromosome. RT-PCR demonstrated that KIR3DL1 was selectively expressed by NK cells in both rat and mouse. An epitope-tagged expression construct of mouse KIR3DL1 transfected into 293T cells induced expression of a approximately 55-kDa protein. Our data indicate that KIR receptors may contribute to the NK cell receptor repertoire in rodents, alongside the Ly-49 family.