Studies on the mechanism for entry of vesicular stomatitis virus glycoprotein g mRNA into membrane-bound polyribosome complexes

Glycoprotein mRNA (G mRNA) of vesicular stomatitis virus is synthesized in the cytosol fraction of infected HeLa cells. Shortly after synthesis, this mRNA associates with 40S ribosomal subunits and subsequently forms 80S monosomes in the cytosol fraction. The bulk of labeled G mRNA is then found in polysomes associated with the membrane, without first appearing in the subunit or monomer pool of the membrane-bound fraction. Inhibition of the initiation of protein synthesis by pactamycin or muconomycin A blocks entry of newly synthesized G m RNA into membrane-bound polysomes. Under these circumstances, labeled G mRNA accumulates into the cytosol. Inhibition of the elongation of protein synthesis by cucloheximide, however, allows entry of 60 percent of newly synthesized G mRNA into membrane-bound polysomes. Furthermore, prelabeled G mRNA associated with membrane-bound polysomes is released from the membrane fraction in vivo by pactamycin or mucomycon A and in vitro by 1mM puromycin - 0.5 M KCI. This release is not due to nonspecific effects of the drugs. These results demonstrate that association of G mRNA with membrane-bound polysomes is dependent upon polysome formation and initiation of protein synthesis. Therefore, direct association of the 3' end of G mRNA with the membrane does not appear to be the initial event in the formation of membrane-bound polysomes.     

Hip joint replacement surgery for idiopathic osteoarthritis aggregates in families

In order to determine whether there is a genetic component to hip or knee joint failure due to idiopathic osteoarthritis (OA), we invited patients (probands) undergoing hip or knee arthroplasty for management of idiopathic OA to provide detailed family histories regarding the prevalence of idiopathic OA requiring joint replacement in their siblings. We also invited their spouses to provide detailed family histories about their siblings to serve as a control group. In the probands, we confirmed the diagnosis of idiopathic OA using American College of Rheumatology criteria. The cohorts included the siblings of 635 probands undergoing total hip replacement, the siblings of 486 probands undergoing total knee replacement, and the siblings of 787 spouses. We compared the prevalence of arthroplasty for idiopathic OA among the siblings of the probands with that among the siblings of the spouses, and we used logistic regression to identify independent risk factors for hip and knee arthroplasty in the siblings. Familial aggregation for hip arthroplasty, but not for knee arthroplasty, was observed after controlling for age and sex, suggesting a genetic contribution to end-stage hip OA but not to end-stage knee OA. We conclude that attempts to identify genes that predispose to idiopathic OA resulting in joint failure are more likely to be successful in patients with hip OA than in those with knee OA.     

Nucleoside phosphocholine amphiphile for in vitro DNA transfection

A new transfection reagent based on nucleoside phosphocholine amphiphile leading to high transfection efficacy and low cytotoxicity is described. TEM, ethidium bromide displacement assays, agarose gel electrophoresis and SAXS studies support the formation of lipoplexes for the transfection of CHO cells.     

饲喂黄曲霉毒素B_1大鼠肝中AFB_1-DNA加合物的免疫组织化学研究

应用免疫组织化学ＳＰ法对４例饲喂黄曲霉毒素Ｂ１的Ｗｉｓｔａｒ大鼠肝组织中ＡＦＢ１－ＤＮＡ加合物的染色及常规ＨＥ染色发现,４例肝细胞核均出现异型性,但未见肝细胞坏死、增生灶及肝细胞癌;免疫组化揭示部分肝细胞核出现棕黄色、不均质状的ＡＦＢ１－ＤＮＡ加合物,阳性细胞数占１０～８５％。结果提示免疫组织化学方法可作为一种ＡＦＢ１的定位方法,ＡＦＢ１在动物致癌过程中ＡＦＢ１－ＤＮＡ加合物可能具有启动作用     

Encounter with New Resources Causes Polarized Growth of the Cord-Forming Basidiomycete Phanerochaete velutina on Soil

Abstract The development and physiology of cord-forming saprotrophic basidiomycetes, which form extensive and persistent mycelial networks in woodland ecosystems, can be conveniently studied on non-sterile soil in laboratory microcosms mimicking field conditions. Morphological responses of Phanerochaete velutina mycelial systems to resource encounters, and decay partitioning following encounters, varied according to whether simulated woody litter was unsterile or autoclaved and on whether encounter took place at the mycelial foraging front or behind the margin (simulating litter fall onto established systems in the field). Results show that encounter of discrete resources by P. velutina is rapidly communicated to the entire mycelial system; that resource capture takes high priority at the expense of continued system extension and decay-derived carbon reallocation; and that polarized growth toward newly encountered resources, previously considered to occur infrequently with this species, may be readily detected using image analysis techniques. Potential advantages of polarized development of P. velutina are discussed.     

Reproductive biology of two tree species of Leguminosae in a Montane Rain Forest in southeastern Brazil

Studies on sympatric species that belong to the same taxonomic group and have the same pattern of pollination and seed dispersion, but different patterns of geographical distribution and structural parameters may be worthwhile to understand the evolution of their compatibility system. We studied the floral biology, pollinators and reproductive systems of two tree species in Itatiaia, an area covered with montane rain forest. Pseudopiptadenia contorta is widespread in Brazil but is present at a low relative density at the study site, while Pseudopiptadenia leptostachya is restrictively distributed but presents one of its highest relative density values in Itatiaia. Both species have small flowers arranged in compact spicate raceme inflorescences that constitute the pollination unit. Pollinators are native stingless bees and European honeybees that collect pollen from their nectarless flowers. Although both species have similar floral characteristics and pollination system, their compatibility system differs. Fruit set after manual pollinations and observation of the pollen tube growth showed that P. leptostachya is self-compatible while P. contorta only set fruits after cross-pollinations, and is thus a self-incompatible species. However, fruit set did not differ between the species, indicating that structural parameters are not affected by the compatibility system. Thus, the difference between these two species in terms of reproductive system may be related to other factors such as patterns of geographical distribution.     

Good agreements between self and clinician-collected specimens for the detection of human papillomavirus in Brazilian patients

Women infected with human papillomavirus (HPV) are at a higher risk of developing cervical lesions. In the current study, self and clinician-collected vaginal and cervical samples from women were processed to detect HPV DNA using polymerase chain reaction (PCR) with PGMY09/11 primers. HPV genotypes were determined using type-specific PCR. HPV DNA detection showed good concordance between self and clinician-collected samples (84.6%; kappa = 0.72). HPV infection was found in 30% women and genotyping was more concordant among high-risk HPV (HR-HPV) than low-risk HPV (HR-HPV). HPV16 was the most frequently detected among the HR-HPV types. LR-HPV was detected at a higher frequency in self-collected; however, HR-HPV types were more frequently identified in clinician-collected samples than in self-collected samples. HPV infections of multiple types were detected in 20.5% of clinician-collected samples and 15.5% of self-collected samples. In this study, we demonstrated that the HPV DNA detection rate in self-collected samples has good agreement with that of clinician-collected samples. Self-collected sampling, as a primary prevention strategy in countries with few resources, could be effective for identifying cases of HR-HPV, being more acceptable. The use of this method would enhance the coverage of screening programs for cervical cancer.     

Intestinal barrier function in response to abundant or depleted mucosal glutathione in Salmonella-infected rats

Background  

Glutathione, the main antioxidant of intestinal epithelial cells, is suggested to play an important role in gut barrier function and prevention of inflammation-related oxidative damage as induced by acute bacterial infection. Most studies on intestinal glutathione focus on oxidative stress reduction without considering functional disease outcome. Our aim was to determine whether depletion or maintenance of intestinal glutathione changes susceptibility of rats to Salmonella infection and associated inflammation.     

Anti-Angiogenic/Vascular Effects of the mTOR Inhibitor Everolimus Are Not Detectable by FDG/FLT-PET

Noninvasive functional imaging of tumors can provide valuable early-response biomarkers, in particular, for targeted chemotherapy. Using various experimental tumor models, we have investigated the ability of positron emission tomography (PET) measurements of 2-deoxy-2-[¹⁸F]fluoro-glucose (FDG) and 3′-deoxy-3′-[¹⁸F]fluorothymidine (FLT) to detect response to the allosteric mammalian target of rapamycin (mTOR) inhibitor everolimus. Tumor models were declared sensitive (murine melanoma B16/BL6 and human lung H596) or relatively insensitive (human colon HCT116 and cervical KB31), according to the IC₅₀ values (concentration inhibiting cell growth by 50%) for inhibition of proliferation in vitro (<10 nM and >1 µM, respectively). Everolimus strongly inhibited growth of the sensitive models in vivo but also significantly inhibited growth of the insensitive models, an effect attributable to its known anti-angiogenic/vascular properties. However, although tumor FDG and FLT uptake was significantly reduced in the sensitive models, it was not affected in the insensitive models, suggesting that endothelial-directed effects could not be detected by these PET tracers. Consistent with this hypothesis, in a well-vascularized orthotopic rat mammary tumor model, other antiangiogenic agents also failed to affect FDG uptake, despite inhibiting tumor growth. In contrast, the cytotoxic patupilone, a microtubule stabilizer, blocked tumor growth, and markedly reduced FDG uptake. These results suggest that FDG/FLT-PET may not be a suitable method for early markers of response to antiangiogenic agents and mTOR inhibitors in which anti-angiogenic/vascular effects predominate because the method could provide false-negative responses. These conclusions warrant clinical testing.