Immunohistochemical identification of aquaporin 2 in the kidneys of young beef cattle

Aquaporin 2 (AQP2) is a small, integral tetrameric plasma membrane protein that is expressed in mammalian kidneys. The specific constitution of this protein and its selective permeability to water means that AQP2 plays an important role in hypertonic urine production. Immunolocalization of AQP2 has been studied in humans, monkeys, sheep, dogs, rabbits, rats, mice and adult cattle. We analyzed the expression of AQP2 in kidneys of 7-month-old Polish-Friesian var. black and white male calves. AQP2 was localized in the principal cells of collecting ducts in medullary rays penetrating the renal cortex and in the collecting ducts of renal medulla. AQP2 was expressed most strongly in the apical plasma membrane, but expression was observed also in the intracellular vesicles and basolateral plasma membrane. Our study provides new information concerning the immunolocalization of AQP2 in calf kidneys.     

p85alpha regulates osteoblast differentiation by cross-talking with the MAPK pathway

Class IA phosphoinositide 3-kinase (PI3K) is involved in regulating many cellular functions including cell growth, proliferation, cell survival, and differentiation. The p85 regulatory subunit is a critical component of the PI3K signaling pathway. Mesenchymal stem cells (MSC) are multipotent cells that can be differentiated into osteoblasts (OBs), adipocytes, and chondrocytes under defined culture conditions. To determine whether p85α subunit of PI3K affects biological functions of MSCs, bone marrow-derived wild type (WT) and p85α-deficient (p85α(-/-)) cells were employed in this study. Increased cell growth, higher proliferation rate and reduced number of senescent cells were observed in MSCs lacking p85α compare with WT MSCs as evaluated by CFU-F assay, thymidine incorporation assay, and β-galactosidase staining, respectively. These functional changes are associated with the increased cell cycle, increased expression of cyclin D, cyclin E, and reduced expression of p16 and p19 in p85α(-/-) MSCs. In addition, a time-dependent reduction in alkaline phosphatase (ALP) activity and osteocalcin mRNA expression was observed in p85α(-/-) MSCs compared with WT MSCs, suggesting impaired osteoblast differentiation due to p85α deficiency in MSCs. The impaired p85α(-/-) osteoblast differentiation was associated with increased activation of Akt and MAPK. Importantly, bone morphogenic protein 2 (BMP2) was able to intensify the differentiation of osteoblasts derived from WT MSCs, whereas this process was significantly impaired as a result of p85α deficiency. Addition of LY294002, a PI3K inhibitor, did not alter the differentiation of osteoblasts in either genotype. However, application of PD98059, a Mek/MAPK inhibitor, significantly enhanced osteoblast differentiation in WT and p85α(-/-) MSCs. These results suggest that p85α plays an essential role in osteoblast differentiation from MSCs by repressing the activation of MAPK pathway.     

HLA-B18 is associated with decreased levels of isoproterenol-stimulated cAMP in lymphocytes.

One hundred fifty-nine individuals were typed for HLA-A and B antigens and levels of isoproterenol-stimulated, lymphocyte cAMP. No significant age, sex, or caffeine effects on the natural log of the lymphocyte cAMP variable (ln cAMP) were found. A comparison of mean ln cAMP levels between individuals who carried a particular antigen (homozygous or heterozygous) and individuals who did not carry the antigen identified a highly significant decrease in ln cAMP levels associated with the HLA-B18 antigen. We estimated that 18.9% of the variability in ln cAMP was attributable to the HLA-B18 antigen. In addition, 38% of the variability in ln cAMP was attributable to factors that aggregate in families that were independent of the HLA-B18 effect. A weaker association of A10 with lymphocyte cAMP might be due to linkage disequilibrium between A10 and B18.     

Inhibition of arylhydrocarbon hydroxylase and cytochrome P-450 by 20-methylcholanthrene and phenobarbital in guinea pig on excessive doses of ascorbic acid

Treatment of guinea pigs on adequate ascorbic acid (AA) with 20-methylcholanthrene (MCA) and phenobarbital (PB) significantly increased hepatic arylhydrocarbon hydroxylase (AHH), cytochrome P-450 and cytochrome-b5 activities. In lungs, only MCA treatment significantly enhanced the activities of AHH, cytochrome P-450 and cytochrome b5. In animals on excessive doses of AA, there was inhibition of hepatic AHH, cytochrome P-450 and cytochrome b5 levels by treatment with these xenobiotics. Also, inhibition was observed in pulmonary AHH and cytochrome P-450 levels. The relevance of these observations in excessive AA-fed guinea pigs to carcinogenesis requires further extensive investigations.     

Sufficient-completeness, ground-reducibility and their complexity

Summary The sufficient-completeness property of equational algebraic specifications has been found useful in providing guidelines for designing abstract data type specifications as well as in proving inductive properties using the induction-less-induction method. The sufficient-completeness property is known to be undecidable in general. In an earlier paper, it was shown to be decidable for constructor-preserving, complete (canonical) term rewriting systems, even when there are relations among constructor symbols. In this paper, the complexity of the sufficient-completeness property is analyzed for different classes of term rewriting systems. A number of results about the complexity of the sufficient-completeness property for complete (canonical) term rewriting systems are proved: (i) The problem is co-NP-complete for term rewriting systems with free constructors (i.e., no relations among constructors are allowed), (ii) the problem remains co-NP-complete for term rewriting systems with unary and nullary constructors, even when there are relations among constructors, (iii) the problem is provably in almost exponential time for left-linear term rewriting systems with relations among constructors, and (iv) for left-linear complete constructor-preserving rewriting systems, the problem can be decided in steps exponential innlogn wheren is the size of the rewriting system. No better lower-bound for the complexity of the sufficient-completeness property for complete (canonical) term rewriting system with nonlinear left-hand sides is known. An algorithm for left-linear complete constructor-preserving rewriting systems is also discussed. Finally, the sufficient-completeness property is shown to be undecidable for non-linear complete term rewriting systems with associative functions. These complexity results also apply to the ground-reducibility property (also called inductive-reducibility) which is known to be directly related to the sufficient-completeness property.Some of the results in this paper were reported in a paper titled Complexity of Sufficient-Completeness presented at theSixth Conf. on Foundations of Software Technology and Theoretical Computer Science, New Delhi, India, Dec. 1986. The term quasi-reducibility is replaced in this paper by ground-reducibility as the latter seems to convey a lot more about the concept than the former.Partially supported by the National Science Foundation Grant nos. CCR-8408461 and CCR-8906678Partially supported by the National Science Foundation Grant nos. CCR-8408461 and CCR-9009414Partially supported by the National Science Foundation Grant no. DCR-8603184     

Using extensional flow to reveal diverse aggregation landscapes for three IgG1 molecules

Monoclonal antibodies (mAbs) currently dominate the biopharmaceutical sector due to their potency and efficacy against a range of disease targets. These proteinaceous therapeutics are, however, susceptible to unfolding, mis‐folding, and aggregation by environmental perturbations. Aggregation thus poses an enormous challenge to biopharmaceutical development, production, formulation, and storage. Hydrodynamic forces have also been linked to aggregation, but the ability of different flow fields (e.g., shear and extensional flow) to trigger aggregation has remained unclear. To address this question, we previously developed a device that allows the degree of extensional flow to be controlled. Using this device we demonstrated that mAbs are particularly sensitive to the force exerted as a result of this flow‐field. Here, to investigate the utility of this device to bio‐process/biopharmaceutical development, we quantify the effects of the flow field and protein concentration on the aggregation of three mAbs. We show that the response surface of mAbs is distinct from that of bovine serum albumin (BSA) and also that mAbs of similar sequence display diverse sensitivity to hydrodynamic flow. Finally, we show that flow‐induced aggregation of each mAb is ameliorated by different buffers, opening up the possibility of using the device as a formulation tool. Perturbation of the native state by extensional flow may thus allow identification of aggregation‐resistant mAb candidates, their bio‐process parameters and formulation to be optimized earlier in the drug‐discovery pipeline using sub‐milligram quantities of material.     

Kinetics of biosurfactant production by Pseudomonas aeruginosa strain BS2 from industrial wastes

Summary Batch kinetic studies were carried out on rhamnolipid biosurfactant production from synthetic medium, industrial wastes viz. distillery and whey waste as substrates. The results indicated that the specific growth rates ( _max) and specific product formation rates (V _max) from both the wastes are comparatively better than the synthetic medium, revealing that both the industrial wastes (distillery and whey) can be successfully utilized as substrates for biosurfactant production.     

Molecular population genetic analysis of the enn subdivision of group A streptococcal emm-like genes: horizontal gene transfer and restricted variation among enn genes

The group A streptococcal emm-like genes, which encode the cell-surface M and M-like proteins, are divided into distinct mrp, emm and enn subdivisions and are clustered together in a region of the chromosome called the vir regulon. In order to understand the mechanisms involved in the evolution of emm-like genes, a 180bp fragment of the 5 variable region of the enn gene was characterized in 31 strains for which emm sequences and multilocus enzyme electrophoretic profiles have been previously determined. The results demonstrate that nucleotide polymorphisms at the enn locus are generated predominantly by point mutations and short deletions or insertions, and that variation among enn and emm genes has arisen by similar mechanisms. However, diversity at the enn locus is restricted in comparison to the emm locus. Moreover, there is strong evidence for intragenic recombination at the enn locus and the pattern of distribution of emm and enn alleles among strains suggests that these genes may be independently acquired by horizontal transfer and recombination from distinct donor strains, thereby generating a mosaic structure for the vir regulon. The results add to a growing body of evidence that horizontal gene transfer has played a major role in the evolution of Streptococcus pyogenes vir regulons.