Involvement of Rhizobium japonicum O antigen in soybean nodulation.

Non-nodulating mutant strains of Rhizobium japonicum lacked a surface antigen that was present on the wild type. This surface antigen is associated with the O antigen portion of the lipopolysaccharide. Paper chromatography of hydrolyzed lipopolysaccharide and O antigen revealed three major component differences between the non-nodulating strains and the wild type.     

Creating an African HIV Clinical Research and Prevention Trials Network: HIV Prevalence,Incidence and Transmission

HIV epidemiology informs prevention trial design and program planning. Nine clinical research centers (CRC) in sub-Saharan Africa conducted HIV observational epidemiology studies in populations at risk for HIV infection as part of an HIV prevention and vaccine trial network. Annual HIV incidence ranged from below 2% to above 10% and varied by CRC and risk group, with rates above 5% observed in Zambian men in an HIV-discordant relationship, Ugandan men from Lake Victoria fishing communities, men who have sex with men, and several cohorts of women. HIV incidence tended to fall after the first three months in the study and over calendar time. Among suspected transmission pairs, 28% of HIV infections were not from the reported partner. Volunteers with high incidence were successfully identified and enrolled into large scale cohort studies. Over a quarter of new cases in couples acquired infection from persons other than the suspected transmitting partner.     

Disparate associations of HLA class I markers with HIV-1 acquisition and control of viremia in an African population

Background

Acquisition of human immunodeficiency virus type 1 (HIV-1) infection is mediated by a combination of characteristics of the infectious and the susceptible member of a transmission pair, including human behavioral and genetic factors, as well as viral fitness and tropism. Here we report on the impact of established and potential new HLA class I determinants of heterosexual HIV-1 acquisition in the HIV-1-exposed seronegative (HESN) partners of serodiscordant Zambian couples.

Methodology/Principal Findings

We assessed the relationships of behavioral and clinically documented risk factors, index partner viral load, and host genetic markers to HIV-1 transmission among 568 cohabiting couples followed for at least nine months. We genotyped subjects for three classical HLA class I genes known to influence immune control of HIV-1 infection. From 1995 to December 2006, 240 HESNs seroconverted and 328 remained seronegative. In Cox proportional hazards models, HLA-A*68:02 and the B*42-C*17 haplotype in HESN partners were significantly and independently associated with faster HIV-1 acquisition (relative hazards = 1.57 and 1.55; p = 0.007 and 0.013, respectively) after controlling for other previously established contributing factors in the index partner (viral load and specific class I alleles), in the HESN partner (age, gender), or in the couple (behavioral and clinical risk score). Few if any previously implicated class I markers were associated here with the rate of acquiring infection.

Conclusions/Significance

A few HLA class I markers showed modest effects on acquisition of HIV-1 subtype C infection in HESN partners of discordant Zambian couples. However, the striking disparity between those few markers and the more numerous, different markers found to determine HIV-1 disease course makes it highly unlikely that, whatever the influence of class I variation on the rate of infection, the mechanism mediating that phenomenon is identical to that involved in disease control.     

Genetic polymorphims of estrogen receptor alpha −397 PvuII (T>C) and −351 XbaI (A>G) in a portuguese population: prevalence and relation with breast cancer susceptibility

Estrogen receptor alpha (ERα), that mediates the biologic effects of estrogen in estrogen-sensitive tissues like breast, is genetically polymorphic. To evaluate the association between ?397 PvuII (T>C) and ?351 XbaI (A>G) restriction fragment length polymorphisms (RFLPs) in intron 1 of ERα gene and susceptibility of breast cancer, we undertook a case–control study in BRCA1 185delAG and 5382insC/BRCA2 6174delT negative Portuguese women. The study population consisted of 107 patients with histological diagnosis of breast cancer and 121 women with no history of breast cancer. Genomic DNA was extracted from blood samples and genotyping analyses were performed by PCR–RFLP. XbaI polymorphism was associated with a significant reduced risk of breast cancer for carriers of the x allele in homozygozity (OR 0.178; 95 % CI 0.070–0.456; P < 0.001) or heterozigozity (OR 0.223; 95 % CI 0.089–0.561; P = 0.001). The PvuII polymorphism was associated with a non-significantly reduced risk. The combined analysis of PvuII and XbaI polymorphisms revealed none synergistic effect of the two genotypes, except for simultaneous carriers of pp and xx genotypes, that have a reduced risk of breast cancer (OR 0.226; 95 % CI 0.049–1.035; P = 0.044). The combination of PvuII and XbaI genotypes into haplotypes showed that carriers of two copies of the px (ppxx) haplotype had a reduced risk of breast cancer (OR 0.405; 95 % CI 0.194–0.843; P = 0.014), compared with PX (PPXX + PPXx + PpXX + PpXx) haplotypes. PvuII and XbaI polymorphisms were in linkage disequilibrium both in cases (D = 0.044, r² = 0.049, X² = 5.216, P = 0.022) and controls (D = 0.090, r² = 0.139, X² = 16.819, P < 0.001), but not in the entire sample population analyzed as a whole (D = 0.087, r² = 0.0076, X² = 1.733, P = 0.188). In conclusion, in this case–control study we found that ERα gene XbaI polymorphism may modify individual susceptibility for breast cancer in this population.     

THE COMBINED USE OF WHOLE CUPHEA SEEDS CONTAINING MEDIUM CHAIN FATTY ACIDS AND AN EXOGENOUS LIPASE IN PIGLET NUTRITION

In search for an alternative for nutritional antimicrobials in piglet feeding, the effects of adding whole Cuphea seeds, as a natural source of medium chain fatty acids (MCFA), with known antimicrobial effects, and an exogenous lipase to a weaner diet were studied. The foregut flora, the gut morphology, some digestive parameters and the zootechnical performance of weaned piglets were investigated. Thirty newly weaned piglets, initial weight 7.0 ± 0.4 kg, were divided according to litter, sex and weight in two groups (control diet; Cuphea+lipase diet). The Cuphea seeds (lanceolata and ignea) (50 g kg^?1) were substituted for soybean oil (15 g kg^?1), Alphacell (25 g kg^?1) and soy protein isolate (10 g kg^?1) in the control diet. Also 500 mg kg^?1 microbial lipase was added to the Cuphea diet. The piglets were weighted individually on days 0, 3, 7, 14 and 16. Feed intake was recorded per pen during days 0 to 3, 3 to 7, 7 to 14 and 14 to 16. On day 7 five piglets of each experimental group were euthanized for counting the gastric and small intestinal gut flora and for gut morphology at two sites of the small intestine (proximal, distal). The results indicate a trend towards improved performances parameters by feeding Cuphea + lipase. The enzymic released MCFA (1.7 g kg^?1 fresh gastric contents) tended to decrease the number of Coliforms in the proximal small intestine, but increased the number in the stomach and distal small intestine. With Cuphea, the number of Streptococci was significantly lower in small intestine, but not in the stomach, while the number of Lactobacilli was significantly lower in the distal small intestine and tended to be lower in the stomach and proximal small intestine. No differences between the diets were noted for the total anaerobic microbial load in the stomach or in the gut. Feeding Cuphea+lipase resulted in a significantly greater villus height (distal small intestine) and a lesser crypt depth (proximal and distal small intestine) and greater villus/crypt ratio depth (proximal and distal small intestine). The intra-epithelial lymphocyte (IEL) counts per 100 enterocytes were significantly decreased in the proximal small intestine and tended to decrease in the distal small intestine by feeding the Cuphea+lipase diet. Both phenomena are indicative for a more healthy and better functional state of the mucosa. Present results are in line with foregoing research, showing that manipulation of the gut ecosystem by the enzymic in situ released MCFA in the stomach and foregut can result in improved performances of the piglets, which makes the concept a potential alternative for in-feed nutritional antibiotics.     

Auxilin is required for formation of Golgi-derived clathrin-coated vesicles during Drosophila spermatogenesis

Clathrin has previously been implicated in Drosophila male fertility and spermatid individualization. To understand further the role of membrane transport in this process, we analyzed the phenotypes of mutations in Drosophila auxilin (aux), a regulator of clathrin function, in spermatogenesis. Like partial loss-of-function Clathrin heavy chain (Chc) mutants, aux mutant males are sterile and produce no mature sperm. The reproductive defects of aux males were rescued by male germ cell-specific expression of aux, indicating that auxilin function is required autonomously in the germ cells. Furthermore, this rescue depends on both the clathrin-binding and J domains, suggesting that the ability of Aux to bind clathrin and the Hsc70 ATPase is essential for sperm formation. aux mutant spermatids show a deficit in formation of the plasma membrane during elongation, which probably disrupts the subsequent coordinated migration of investment cones during individualization. In wild-type germ cells, GFP-tagged clathrin localized to clusters of vesicular structures near the Golgi. These structures also contained the Golgi-associated clathrin adaptor AP-1, suggesting that they were Golgi-derived. By contrast, in aux mutant cells, clathrin localized to abnormal patches surrounding the Golgi and its colocalization with AP-1 was disrupted. Based on these results, we propose that Golgi-derived clathrin-positive vesicles are normally required for sustaining the plasma membrane increase necessary for spermatid differentiation. Our data suggest that Aux participates in forming these Golgi-derived clathrin-positive vesicles and that Aux, therefore, has a role in the secretory pathway.     

Comparative metabolic rates of common western North Atlantic Ocean sciaenid fishes

The resting metabolic rates (R(R)) of western North Atlantic Ocean sciaenids, such as Atlantic croaker Micropogonias undulatus, spot Leiostomus xanthurus and kingfishes Menticirrhus spp., as well as the active metabolic rates (R(A)) of M. undulatus and L. xanthurus were investigated to facilitate inter and intraspecific comparisons of their energetic ecology. The R(R) of M. undulatus and L. xanthurus were typical for fishes with similar lifestyles. The R(R) of Menticirrhus spp. were elevated relative to those of M. undulatus and L. xanthurus, but below those of high-energy-demand species such as tunas Thunnus spp. and dolphinfish Coryphaena hippurus. Repeated-measures non-linear mixed-effects models were applied to account for within-individual autocorrelation and corrected for non-constant variance typical of noisy R(A) data sets. Repeated-measures models incorporating autoregressive first-order [AR(1)] and autoregressive moving average (ARMA) covariances provided significantly superior fits, more precise parameter estimates (i.e. reduced s.e.) and y-intercept estimates that more closely approximated measured R(R) for M. undulatus and L. xanthurus than standard least-squares regression procedures.     

The effect of stimulation frequency on the transmural ventricular monophasic action potential in yellowfin tuna Thunnus albacares

Monophasic action potentials (MAPs) were recorded from the spongy and compact layers of the yellowfin tuna Thunnus albacares ventricle as stimulation frequency was increased. MAP duration decreased with increase in stimulation frequency in both the spongy and compact myocardial layers, but no significant difference in MAP duration was observed between the layers.