Increased luminal pH in the epididymis of infertile c-ros knockout mice and the expression of sodium-hydrogen exchangers and vacuolar proton pump H+-ATPase

Transgenic mice targeted for the c-ros gene, which are fertile when heterozygous (HET), but infertile when homozygous (knockout, KO) and associated with failure in pubertal differentiation of the epididymal initial segment, provide a model for studying the role of the epididymal luminal environment in sperm development. Luminal fluid from the cauda epididymidis was measured by both ion-selective microelectrodes and pH strips to be 0.3 pH units higher in the KO than HET. Of the genes responsible for luminal acidification, expression of mRNA of vacuolar H(+)-ATPase was found in all epididymal regions, but with no difference between KO and HET. Immunohistochemistry showed its presence in epithelial apical cells and clear cells. The Na(+)-hydrogen exchanger NHE2 was expressed at mRNA and protein levels in the caput but only marginally detectable if at all in the distal epididymis. This was compensated for by NHE3 which was expressed strongest in the cauda region, in agreement with immunohistochemical staining. Quantification of Western blot data revealed slight, but significant, decreases of NHE2 in the caput and of NHE3 in the cauda in the KO mice. The increase in luminal fluid pH in the KO mice could also be contributed to by other epithelial regulating factors including the Na(+)-dependent glutamate transporter EAAC1 formerly reported to be down regulated in the KO.     

Enteropathogens associated with acute diarrhea in community and hospital patients in Jakarta,Indonesia

The prevalence of bacteria, parasite and viral pathogens in 3875 patients with diarrhea in community and hospital settings from March 1997 through August 1999 in Jakarta, Indonesia was determined using routine bacteriology and molecular assay techniques. Bacterial pathogens isolated from hospital patients were, in decreasing frequency, Vibrio cholerae O1, Shigella flexneri, Salmonella spp. and Campylobacter jejuni, while S. flexneri, V. cholerae O1, Salmonella spp. and C. jejuni were isolated from the community patients. V. cholerae O1 was isolated more frequently (P<0.005) from the hospital patients than the community patients. Overall, bacterial pathogens were isolated from 538 of 3875 (14%) enrolled cases of diarrhea. Enterotoxigenic Escherichia coli were detected in 218 (18%) of 1244 rectal swabs. A small percentage of enterohemorrhagic E. coli (1%) and of Clostridium difficile (1.3%) was detected. Parasitic examination of 389 samples resulted in 43 (11%) positives comprising Ascaris lumbricoides (1.5%), Blastocystis hominis (5.7%), Giardia lamblia (0.8%), Trichuris trichiura (2.1%) and Endolimax nana (0.5%). Rotavirus (37.5%), adenovirus (3.3%) and Norwalk-like virus (17.6%) were also detected. Antimicrobial resistance was observed among some isolates. Bacterial isolates were susceptible to quinolones, with the exception of some isolates of C. jejuni which were resistant to ciprofloxacin, nalidixic acid and norfloxacin. Data obtained from this community- and hospital-based study will enable the Indonesian Ministry of Health to plan relevant studies on diarrheal diseases in the archipelago.     

Novel isomarabarican triterpenes, exhibiting selective anti-proliferative activity against vascular endothelial cells, from marine sponge Rhabdastrella globostellata

Four novel globostellatic acid X methyl esters (1-4) having isomarabarican-type triterpenoidal skeleton and three related new compounds (5-7) were isolated from the marine sponge Rhabdastrella globostellata, as selective anti-proliferative agents against human umbilical vein endothelial cells (HUVECs). Those chemical structures were elucidated by the detailed 2D NMR analysis. Two globostellatic acid X methyl esters (3 and 4) having 13E-geometry were found to inhibit proliferation of HUVECs, 80- to 250-fold selectively in comparison with several other cell lines. 13E,17E-Globostellatic acid X methyl ester (4) also inhibited bFGF-induced tubular formation and VEGF-induced migration of HUVECs. Moreover, 4 induced apoptosis of HUVECs, whereas it exhibited no effect on VEGF-induced phosphorylation of ERK1/2 in HUVECs.     

HNF1B and endometrial cancer risk: results from the PAGE study

We examined the association between HNF1B variants identified in a recent genome-wide association study and endometrial cancer in two large case-control studies nested in prospective cohorts: the Multiethnic Cohort Study (MEC) and the Women's Health Initiative (WHI) as part of the Population Architecture using Genomics and Epidemiology (PAGE) study. A total of 1,357 incident cases of invasive endometrial cancer and 7,609 controls were included in the analysis (MEC: 426 cases/3,854 controls; WHI: 931 cases/3,755 controls). The majority of women in the WHI were European American, while the MEC included sizable numbers of African Americans, Japanese and Latinos. We estimated the odds ratios (ORs) per allele and 95% confidence intervals (CIs) of each SNP using unconditional logistic regression adjusting for age, body mass index, and four principal components of ancestry informative markers. The combined ORs were estimated using fixed effect models. Rs4430796 and rs7501939 were associated with endometrial cancer risk in MEC and WHI with no heterogeneity observed across racial/ethnic groups (P ≥ 0.21) or between studies (P ≥ 0.70). The OR(per allele) was 0.82 (95% CI: 0.75, 0.89; P = 5.63 × 10(-6)) for rs4430796 (G allele) and 0.79 (95% CI: 0.73, 0.87; P = 3.77 × 10(-7)) for rs7501939 (A allele). The associations with the risk of Type I and Type II tumors were similar (P ≥ 0.19). Adjustment for additional endometrial cancer risk factors such as parity, oral contraceptive use, menopausal hormone use, and smoking status had little effect on the results. In conclusion, HNF1B SNPs are associated with risk of endometrial cancer and that the associated relative risks are similar for Type I and Type II tumors.     

Colonization with Heligmosomoides polygyrus suppresses mucosal IL-17 production

Helminth exposure appears to protect hosts from inappropriate inflammatory responses, such as those causing inflammatory bowel disease. A recently identified, strongly proinflammatory limb of the immune response is characterized by T cell IL-17 production. Many autoimmune type inflammatory diseases are associated with IL-17 release. Because helminths protect from these diseases, we examined IL-17 production in helminth-colonized mice. We colonized mice with Heligmosomoides polygyrus, an intestinal helminth, and analyzed IL-17 production by lamina propria mononuclear cells (LPMC) and mesenteric lymph node (MLN) cells. Colonization with H. polygyrus reduces IL-17A mRNA by MLN cells and inhibits IL-17 production by cultured LPMC and MLN cells. Helminth exposure augments IL-4 and IL-10 production. Blocking both IL-4 and IL-10, but not IL-10 alone, restores IL-17 production in vitro. Colonization of colitic IL-10-deficient mice with H. polygyrus suppresses LPMC IL-17 production and improves colitis. Ab-mediated blockade of IL-17 improves colitis in IL-10-deficient mice. Thus, helminth-associated inhibition of IL-17 production is most likely an important mechanism mediating protection from inappropriate intestinal inflammation.     

Hormonal correlates of parental behavior in yellow-eyed penguins (Megadyptes antipodes)

Penguins show varying degrees of brood reduction behavior, from obligate brood reducers to brood maximizers, and we hypothesize that this is associated with differences in prolactin secretion. To address this hypothesis, we determined the breeding season prolactin profile of the yellow-eyed penguin (Megadyptes antipodes) for comparison with those of other penguin species found in the literature. We also measured sex steroid plasma concentrations to better characterize the reproductive cycle of the species. Plasma concentrations of prolactin increased from early in the season, reaching a peak during late incubation, and remained elevated up to the guard period. This general pattern was similar to that of other penguins for which we have corresponding data. However, we found that throughout the laying period, prolactin titers in yellow-eyed penguins remained elevated while they fell to basal levels after the laying of the first egg in macaroni penguins, which corresponds to differences in incubation behavior during this time. We conclude, therefore, that differences in the brood reduction behavior in penguins, may be reflected in the pattern of PRL concentrations around the time of egg laying.     

Water temperature and some water quality in Lake Toba,a tropical volcanic lake

Limnology - In 2014, 2018 and 2021, we measured the vertical distributions of several water quality indicators in Lake Toba, a representative large tropical lake. This lake has a north basin (NB)...     

Mapping quantitative trait loci (QTLs) for resistance to Cercospora leaf spot disease (Cercospora beticola Sacc.) in sugar beet (Beta vulgaris L.)

The breeding of sugar beet varieties that combine resistance to Cercospora and high yield under non-diseased conditions is a major challenge to the breeder. The understanding of the quantitative trait loci (QTLs) contributing to Cercospora resistance offers one route to solving this problem. A QTL analysis of Cercospora resistance in sugar beet was carried out using a linkage map based on AFLP and RFLP markers. Two different screening methods for Cercospora resistance (a field test at Copparo, Italy, under natural infection, and a newly-developed leaf disc test) were used to estimate the level of Cercospora resistance; the correlation between scores from the field (at 162 days after sowing) and the leaf disc test was significant. QTL analysis was based on F₂ and F₃ (half-sib family) generations derived from crosses between diploid single plants of 93164P (resistant to Cercospora leaf spot disease) and 95098P (susceptible). Four QTLs associated with Cercospora resistance (based on Lsmean data of the leaf disc test) on chromosomes III, IV, VII and IX were revealed using Composite interval mapping. To produce populations segregating for leaf spot resistance as a single Mendelian factor, we selected for plants heterozygous for only one of the QTLs (on chromosome IV or IX) but homozygous for the others. Received: 1 September 1999 / Accepted 7 October 1999     

Up-Regulation of the Inwardly Rectifying K+ Channel Kir2.1 (KCNJ2) by Protein Kinase B (PKB/Akt) and PIKfyve

The inward rectifier K⁺ channel Kir2.1 contributes to the maintenance of the resting cell membrane potential in excitable cells. Loss of function mutations of KCNJ2 encoding Kir2.1 result in Andersen-Tawil syndrome, a disorder characterized by periodic paralysis, cardiac arrhythmia, and dysmorphic features. The ubiquitously expressed protein kinase B (PKB/Akt) activates the phosphatidylinositol-3-phosphate-5-kinase PIKfyve, which in turn regulates a variety of carriers and channels. The present study explored whether PKB/PIKfve contributes to the regulation of Kir2.1. To this end, cRNA encoding Kir2.1 was injected into Xenopus oocytes with and without additional injection of cRNA encoding wild type PKB (PKB), constitutively active ^T308D,S473DPKB or inactive ^T308A,S473APKB. Kir2.1 activity was determined by two-electrode voltage-clamp. As a result, PKB and ^T308D,S473DPKB, but not ^T308A,S473APKB, significantly increased Kir2.1-mediated currents. The effect of PKB was mimicked by coexpression of PIKfyve but not of ^S318APikfyve lacking the PKB phosphorylation site. The decay of Kir2.1-mediated currents after inhibition of channel insertion into the cell membrane by brefeldin A (5 μM) was similar in oocytes expressing Kir2.1 + PKB or Kir2.1 + PIKfyve to those expressing Kir2.1 alone, suggesting that PKB and PIKfyve influence channel insertion into rather than channel retrieval from the cell membrane. In conclusion, PKB and PIKfyve are novel regulators of Kir2.1.