Localization of sequences regulating ancestral and acquired sites of esterase6 activity in Drosophila melanogaster

We have broadly defined the DNA regions regulating esterase6 activity in several life stages and tissue types of D. melanogaster using P- element-mediated transformation of constructs that contain the esterase6 coding region and deletions or substitutions in 5' or 3' flanking DNA. Hemolymph is a conserved ancestral site of EST6 activity in Drosophila and the primary sequences regulating its activity lie between -171 and -25 bp relative to the translation initiation site: deletion of these sequences decrease activity approximately 20-fold. Hemolymph activity is also modulated by four other DNA regions, three of which lie 5' and one of which lies 3' of the coding region. Of these, two have positive and two have negative effects, each of approximately twofold. Esterase6 activity is present also in two male reproductive tract tissues; the ejaculatory bulb, which is another ancestral activity site, and the ejaculatory duct, which is a recently acquired site within the melanogaster species subgroup. Activities in these tissues are at least in part independently regulated: activity in the ejaculatory bulb is conferred by sequences between -273 and -172 bp (threefold decrease when deleted), while activity in the ejaculatory duct is conferred by more distal sequences between -844 and -614 bp (fourfold decrease when deleted). The reproductive tract activity is further modulated by two additional DNA regions, one in 5' DNA (-613 to -284 bp; threefold decrease when deleted) and the other in 3' DNA (+1860 to +2731 bp; threefold decrease when deleted) that probably overlaps the adjacent esteraseP gene. Collating these data with previous studies suggests that expression of EST6 in the ancestral sites is mainly regulated by conserved proximal sequences while more variable distal sequences regulate expression in the acquired ejaculatory duct site.      

Mitochondrial DNA structure and colony expansion dynamics of New Zealand fur seals (Arctocephalus forsteri) around Banks Peninsula

New Zealand fur seals are one of many pinniped species that survived the commercial sealing of the eighteenth and nineteenth centuries in dangerously low numbers. After the enforcement of a series of protection measures in the early twentieth century, New Zealand fur seals began to recover from the brink of extinction. We examined the New Zealand fur seal populations of Banks Peninsula, South Island, New Zealand using the mitochondrial DNA control region. We identified a panmictic population structure around Banks Peninsula. The most abundant haplotype in the area showed a slight significant aggregated structure. The Horseshoe Bay colony showed the least number of shared haplotypes with other colonies, suggesting a different origin of re-colonisation of this specific colony. The effective population size of the New Zealand fur seal population at Banks Peninsula was estimated at approximately 2500 individuals. The exponential population growth rate parameter for the area was 35, which corresponds to an expanding population. In general, samples from adjacent colonies shared 4.4 haplotypes while samples collected from colonies separated by between five and eight bays shared 1.9 haplotypes. The genetic data support the spill-over dynamics of colony expansion already suggested for this species. Approximate Bayesian computations analysis suggests re-colonisation of the area from two main clades identified across New Zealand with a most likely admixture coefficient of 0.41 to form the Banks Peninsula population. Approximate Bayesian computations analysis estimated a founder population size of approximately 372 breeding individuals for the area, which then rapidly increased in size with successive waves of external recruitment. The population of fur seals in the area is probably in the late phase of maturity in the colony expansion dynamic.     

CXC chemokine ligand 16 promotes integrin-mediated adhesion of liver-infiltrating lymphocytes to cholangiocytes and hepatocytes within the inflamed human liver

Lymphocyte recruitment to the liver is critical for viral clearance in acute hepatitis and in the pathogenesis of chronic inflammatory liver disease when persistent chronic inflammation leads to fibrosis and cirrhosis. Chemokines regulate leukocyte recruitment and positioning in tissues and are thus critical regulators of chronic inflammation. The chemokine CXCL16, which is found in liver tissue, exists in a transmembrane as well as soluble form, providing a potential mechanism for localization to particular structures. We studied the role of CXCL16 and its receptor CXCR6 in lymphocyte recruitment and retention in the liver. A higher proportion of CXCR6(+) T cells was detected in blood of hepatitis C virus patients compared with healthy subjects, and in chronic inflammatory liver disease >60% of intrahepatic T cells expressed CXCR6, including CD4, CD8, and CD56(+) T cells compared with <30% in matched blood samples. CXCR6(+) lymphocytes were found in association with CXCL16(+) bile ducts in portal tracts and with hepatocytes at sites of interface hepatitis. Analysis of CXCL16 expression and subcellular distribution in cultured human cholangiocytes, sinusoidal endothelial cells, and hepatocytes revealed that all three cell types expressed CXCL16, with the strongest staining seen on cholangiocytes. CXCL16 on the cholangiocyte membrane was able to support lymphocyte adhesion by triggering conformational activation of beta(1) integrins and binding to VCAM-1. Thus, CXCL16 can promote lymphocyte adhesion to epithelial cells and may function to attract and retain effector cells that promote biliary and hepatocyte destruction in inflammatory liver disease.     

Electron acceptors associated with P-700 in Triton solubilized Photosystem I particles from spinach chloroplasts

Flash-induced absorption changes of Triton-solubilized Photosystem I particles from spinach were studied under reducing and/or illumination conditions that serve to alter the state of bound electron acceptors. By monitoring the decay of P-700 following each of a train of flashes, we found that P-430 or components resembling it can hold 2 equivalents of electrons transferred upon successive illuminations. This requires the presence of a good electron donor, reduced phenazine methosulfate or neutral red, otherwise the back reaction of P-700⁺ with P-430 occurs in about 30 ms. If the two P-430 sites, designated Centers A and B, are first reduced by preilluminating flashes or chemically by dithionite under anaerobic conditions, then subsequent laser flashes generate a 250 μs back reaction of P-700⁺, which we associate with a more primary electron acceptor A₂. In turn, when A₂ is reduced by background (continuous) illumination in presence of neutral red and under strongly reducing conditions, laser flashes then produce a much faster (3 μs) back reaction at wavelengths characteristic of P-700. We associate this with another more primary electron acceptor, A₁, which functions very close to P-700. The organization of these components probably corresponds to the sequence $\text{P-700-}\text{A}{}_1\text{-}\text{A}{}_2\text{-P-430[}\text{A}\text{B}\text{]}$. The relation of the optical components to acceptor species detected by EPR, by electron-spin polarization or in terms of peptide components of Photosystem I is discussed.Preliminary experiments with broken chloroplasts suggest that an analogous situation occurs there, as well.     

MMP-13 selective α-sulfone hydroxamates: a survey of P1' heterocyclic amide isosteres

Seeking compounds preferentially potent and selective for MMP-13, we reported in the preceding Letter on a series of hydroxamic acids with a flexible benzamide tail groups.^1a Here, we replace the amide moiety with non-hydrolyzable heterocycles in an effort to improve half-life. We identify a hydroxamate tetrazole 4e that spares MMP-1 and -14, shows >400-fold selectivity versus MMP-8 and >600-fold selectivity versus MMP-2, and has a 4.8 h half-life in rats. X-ray data (1.9 Å) for tetrazole 4c is presented.     

New species of the genus Cyamops Melander from New Zealand (Diptera, Periscelididae, Stenomicrinae)

Two new species of the genus Cyamops (Diptera: Periscelididae), the first from New Zealand, are described. The two newly described species are: Cyamops alessandrae and Cyamops crosbyi. A key to the genera of the subfamily Stenomicrinae and to the species of Cyamops from the Australasian/Oceanian Region and detailed illustrations of structures of the male terminalia are provided.     

Association of 25-Hydroxyvitamin D status and genetic variation in the vitamin D metabolic pathway with FEV1 in the Framingham Heart Study

Background

Vitamin D is associated with lung function in cross-sectional studies, and vitamin D inadequacy is hypothesized to play a role in the pathogenesis of chronic obstructive pulmonary disease. Further data are needed to clarify the relation between vitamin D status, genetic variation in vitamin D metabolic genes, and cross-sectional and longitudinal changes in lung function in healthy adults.

Methods

We estimated the association between serum 25-hydroxyvitamin D [25(OH)D] and cross-sectional forced expiratory volume in the first second (FEV₁) in Framingham Heart Study (FHS) Offspring and Third Generation participants and the association between serum 25(OH)D and longitudinal change in FEV₁ in Third Generation participants using linear mixed-effects models. Using a gene-based approach, we investigated the association between 241 SNPs in 6 select vitamin D metabolic genes in relation to longitudinal change in FEV₁ in Offspring participants and pursued replication of these findings in a meta-analyzed set of 4 independent cohorts.

Results

We found a positive cross-sectional association between 25(OH)D and FEV₁ in FHS Offspring and Third Generation participants (P = 0.004). There was little or no association between 25(OH)D and longitudinal change in FEV₁ in Third Generation participants (P = 0.97). In Offspring participants, the CYP2R1 gene, hypothesized to influence usual serum 25(OH)D status, was associated with longitudinal change in FEV₁ (gene-based P < 0.05). The most significantly associated SNP from CYP2R1 had a consistent direction of association with FEV₁ in the meta-analyzed set of replication cohorts, but the association did not reach statistical significance thresholds (P = 0.09).

Conclusions

Serum 25(OH)D status was associated with cross-sectional FEV₁, but not longitudinal change in FEV₁. The inconsistent associations may be driven by differences in the groups studied. CYP2R1 demonstrated a gene-based association with longitudinal change in FEV₁ and is a promising candidate gene for further studies.

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-015-0238-y) contains supplementary material, which is available to authorized users.     

Regulation of cytochrome P-450c by glucocorticoids and polycyclic aromatic hydrocarbons in cultured fetal rat hepatocytes

The actions of polycyclic aromatic hydrocarbons and glucocorticoids to regulate the synthesis of cytochrome P-450c (the major isozyme induced by polycyclic aromatic hydrocarbons) were investigated in fetal rat hepatocytes maintained in primary monolayer culture. Treatment of hepatocytes in culture with 1,2-benzanthracene resulted in a 50-fold increase in 7-ethoxycoumarin O-deethylase activity. The level of P-450c increased in the cells in a time-dependent fashion as determined by immunoelectrophoretic analysis. The inductive effect of BA was potentiated approximately 1.6- to 2.3-fold when 1 microM dexamethasone was included in the culture medium. However, dexamethasone alone had little or no effect on the induction of P-450c. The rate of synthesis of P-450c was examined by immunoisolation of the specific isozyme from total cellular proteins radiolabeled with [35S]methionine and from the protein products formed during in vitro translation of the isolated mRNA. In addition, the amount of mRNA specific for cytochrome P-450c was determined by Northern blot analysis of RNA extracted from cultured cells. The changes in the rates of synthesis and mRNA levels were found to parallel the changes in enzyme activity. The concentration of dexamethasone required to cause a half-maximal increase in P-450c content in the presence of 1,2-benzanthracene was between 10(-8) and 10(-7) M. It is concluded that glucocorticoids act synergistically with polycyclic aromatic hydrocarbons to increase the levels of P-450c expressed in the fetal rat liver, and that this action is likely mediated by the classical type II glucocorticoid receptor.