The effect of an acute energy deficit on the hormone profile of dominant follicles in dairy cows

The effect of an acute energy deficit on the hormone balance of dominant follicles was studied in six normally-cycling, high-yielding Italian Friesian cows at 60 and 90 days after calving. At 60 days after calving, the cows, which had been fed according to their maintenance and production requirements, were synchronized and follicular fluid was collected from the dominant follicles under ultrasound guidance. At 90 days after calving, the same protocol was used on the same cows, which had been subjected to an acute dietary restriction since the day of the second prostaglandin treatment for synchronization. At the follicular level, the dietary restriction caused a significant reduction (P < 0.05) in the concentration of estradiol-17beta and a significant increase (P < 0.05) in NEFA. There were no significant differences in follicular diameter, follicular concentrations of progesterone, and Insulin-like Growth Factor-I (IGF-I). The amount of IGFBP2 and IGFBP3 in follicular fluid increased. The results suggest that an acute dietary restriction induces substantial changes at the dominant follicle level, despite the fact that the recruitment and selection phase occurred before the cows' diet was restricted.     

Evaluation of DNA polymorphisms amplified by arbitrary primers (RAPD) as genetically associated elements to differentiate virulent and non-virulent Paracoccidioides brasiliensis isolates

Randomly amplified polymorphic DNA (RAPD) analysis of 35 Paracoccidioides brasiliensis isolates was carried out to evaluate the correlation of RAPD profiles with the virulence degree or the type of the clinical manifestations of human paracoccidioidomycosis. The dendrogram presented two main groups sharing 64% genetic similarity. Group A included two isolates from patients with chronic paracoccidioidomycosis; group B comprised the following isolates showing 65% similarity: two non-virulent, six attenuated, five virulent, eight from patients with chronic paracoccidioidomycosis and two from patients with acute paracoccidioidomycosis. The virulent Pb18 isolate and six attenuated or non-virulent samples derived from it were genetically indistinguishable (100% of similarity). Thus, in our study, RAPD patterns could not discriminate among 35 P. brasiliensis isolates according to their differences either in the degree of virulence or in the type of the clinical manifestation of this fungal infection.     

The selenoprotein GPX4 is essential for mouse development and protects from radiation and oxidative damage insults

Lipid peroxidation has been implicated in a variety of pathophysiological processes, including inflammation, atherogenesis, neurodegeneration, and the ageing process. Phospholipid hydroperoxide glutathione peroxidase (GPX4) is the only major antioxidant enzyme known to directly reduce phospholipid hydroperoxides within membranes and lipoproteins, acting in conjunction with alpha tocopherol (vitamin E) to inhibit lipid peroxidation. Here we describe the generation and characterization of GPX4-deficient mice by targeted disruption of the murine Gpx4 locus through homologous recombination in embryonic stem cells. Gpx4(-/-) embryos die in utero by midgestation (E7.5) and are associated with a lack of normal structural compartmentalization. Gpx4(+/-) mice display reduced levels of Gpx4 mRNA and protein in various tissues. Interestingly, cell lines derived from Gpx4(+/-) mice are markedly sensitive to inducers of oxidative stress, including gamma-irradiation, paraquat, tert-butylhydroperoxide, and hydrogen peroxide, as compared to cell lines derived from wild-type control littermates. Gpx4(+/-) mice also display reduced survival in response to gamma-irradiation. Our observations establish GPX4 as an essential antioxidant enzyme in mice and suggest that it performs broad functions as a component of the mammalian antioxidant network.     

Control of the expression of human neuropeptide Y by leptin: in vitro studies

Neuropeptide Y (NPY) participates in the regulation of reproduction and food intake. The adipose-secreted hormone, leptin, has also been involved in these processes, and has been shown to exert its effects in part by controlling NPY synthesis and release at the hypothalamic level. In the present study, we utilized the SH-SY5Y human neuroblastoma cell line, to study the leptin-NPY interrelationships. SH-SY5Y cells were found to express leptin receptors (RT-PCR and Western blot analyses). A 24-h treatment with leptin at different concentrations did not affect NPY gene expression, but resulted in a stimulation of NPY release. This stimulated secretion was blocked by the combined treatment with leptin and the muscarinic agonist carbachol or the phorbol ester TPA. Leptin and carbachol also caused an increased intracellular content of NPY. In conclusion, the SH-SY5Y human neuroblastoma cell line appears to be a suitable in vitro model for studying the pharmacological effects of leptin on the biosynthesis and secretion of NPY.     

Prevention of diseases caused by Staphylococcus aureus using the peptide RIP

Staphylococcus aureus causes many diseases including cellulitis, keratitis, osteomyelitis, septic arthritis and mastitis. The heptapeptide RIP has been shown to prevent cellulitis in mice, which was induced by S. aureus strain Smith diffuse. Here we show that RIP can also significantly reduce the overall pathology and delay the onset of disease symptoms in several other models of S. aureus infections, including: keratitis (tested in rabbits against S. aureus 8325-4), osteomyelitis (tested in rabbits against S. aureus MS), mastitis (tested in cows against S. aureus Newbould 305, AE-1, and environmental infections) and septic arthritis (tested in mice against S. aureus LS-1). These findings substantiate that RIP is not strain specific in its inhibitory activity and that RIP is an effective inhibitor of bacterial pathology at multiple body sites following diverse routes and doses of administration. These findings strongly evidence the potential value of RIP as a chemotherapeutic agent.     

EVIDENCE FOR SIGNIFICANT DIFFERENCES IN NUCLEAR DNA CONTENT BETWEEN TWO GEOGRAPHICALLY ISOLATED CLONES OF ARMILLARIA MELLEA

Several collections of Armillaria mellea (Vahl: Fr.) Kummer basidiocarps were screened for relative nuclear DNA content using microspectrophotometric techniques. One collection from the Pacific Northwest showed relative DNA values approximately 30% higher than a reference collection from College Park, Maryland. Corresponding differences in nuclear volumes were also observed. It is postulated that the Washington isolate may represent a stable aneuploid or polyploid clone of the species.     

A DNA Vaccine against Yellow Fever Virus: Development and Evaluation

Attenuated yellow fever (YF) virus 17D/17DD vaccines are the only available protection from YF infection, which remains a significant source of morbidity and mortality in the tropical areas of the world. The attenuated YF virus vaccine, which is used worldwide, generates both long-lasting neutralizing antibodies and strong T-cell responses. However, on rare occasions, this vaccine has toxic side effects that can be fatal. This study presents the design of two non-viral DNA-based antigen formulations and the characterization of their expression and immunological properties. The two antigen formulations consist of DNA encoding the full-length envelope protein (p/YFE) or the full-length envelope protein fused to the lysosomal-associated membrane protein signal, LAMP-1 (pL/YFE), aimed at diverting antigen processing/presentation through the major histocompatibility complex II precursor compartments. The immune responses triggered by these formulations were evaluated in H2b and H2d backgrounds, corresponding to the C57Bl/6 and BALB/c mice strains, respectively. Both DNA constructs were able to induce very strong T-cell responses of similar magnitude against almost all epitopes that are also generated by the YF 17DD vaccine. The pL/YFE formulation performed best overall. In addition to the T-cell response, it was also able to stimulate high titers of anti-YF neutralizing antibodies comparable to the levels elicited by the 17DD vaccine. More importantly, the pL/YFE vaccine conferred 100% protection against the YF virus in intracerebrally challenged mice. These results indicate that pL/YFE DNA is an excellent vaccine candidate and should be considered for further developmental studies.