Impaired Surfactant Production by Alveolar Epithelial Cells in a SCID-hu Lung Mouse Model of Congenital Human Cytomegalovirus Infection

Human cytomegalovirus (HCMV) is the leading viral cause of birth defects and life-threatening lung-associated diseases in premature infants and immunocompromised children. Although the fetal lung is a major target organ of the virus, HCMV lung pathogenesis has remained unexplored, possibly as a result of extreme host range restriction. To overcome this hurdle, we generated a SCID-hu lung mouse model that closely recapitulates the discrete stages of human lung development in utero. Human fetal lung tissue was implanted into severe combined immunodeficient (CB17-scid) mice and inoculated by direct injection with the VR1814 clinical isolate of HCMV. Virus replication in the fetal lung was assessed by the quantification of infectious virus titers and HCMV genome copies and the detection of HCMV proteins by immunohistochemistry and Western blotting. We show that HCMV efficiently replicated in the lung implants during a 2-week period, forming large viral lesions. The virus productively infected alveolar epithelial and mesenchymal cells, imitating congenital infection of the fetal lung. HCMV replication triggered apoptosis near and within the viral lesions and impaired the production of surfactant proteins in the alveolar epithelium. Our findings highlight that congenital and neonatal HCMV infection can adversely impact lung development, leading to pneumonia and acute lung injury. We have successfully developed a small-animal model that closely recapitulates fetal and neonatal lung development and provides a valuable, biologically relevant tool for an understanding of the lung pathogenesis of HCMV as well as other human respiratory viruses. Additionally, this model would greatly facilitate the development and testing of new antiviral therapies for HCMV along with select human pulmonary pathogens.     

A study on the mechanism of the vanadate-dependent NADH oxidation

The mechanism of the vanadate (V(_v))-dependent oxidation of NADH was different in phosphate buffers and in phosphate-free media. In phosphate-free media (aqueous medium or HEPES buffer) the vanadyl (V(_v)) generated by the direct V(_v)-dependent oxidation of NADH formed a complex with V(_v). In phosphate buffers V(_v) autoxidized instead of forming a complex with V(_v). The generated superoxide radical (O₂⁻) initiated, in turn, a high-rate free radical chain oxidation of NADH. Phosphate did not stimulate the V(_v)-dependent NADH oxidation catalyzed by O₂⁻-generating systems. Monovanadate proved to be a stronger catalyzer of NADH oxidation as compared to polyvanadate.     

Oxidative phosphorylation in membrane vesicles of a gram-positive methylotroph

Membrane preparations, capable of high rates of respiration-linked ATP synthesis, have been obtained from a gram-positive methylotrophic bacterium Bacillus sp. MGA3. NADH, succinate, reduced TMPD and methanol were shown to be suitable substrates for the oxidative phosphorylation. Esterification of orthophosphate was dependent on electron transfer, as evidenced by the requirement for both substrate and oxygen. Phosphorylation was also dependent on ADP and was destroyed by boiling the membrane preparation. The phosphorylation was markedly uncoupled by carbonyl cyanide p-(trichloromethoxy)-phenylhydrazone (CCCP) and was inhibited by N,N-dicyclohexylcarbodiimide (DCCD). KCN caused strong inhibition of substrate oxidation as well as phosphorylation for all substrates tested. Rotenone, amytal and antimycin A caused inhibition when NADH or methanol were used as substrates. Antimycin A inhibited respiration and ATP synthesis with succinate as substrate and had no effect on ascorbate —N,N,N,N-tetramethyl-p-phenylenediimide (TMPD) oxidation by membrane preparations of Bacillus sp. MGA3. P/O ratios determined were 2.4 with NADH, 1.7 with succinate and 0.8 with reduced TMPD. The measured P/O ratio with methanol-oxidizing system was similar to that with NADH (about 2.4).Abbreviations CCCP Carbonyl cyanide p-(trichloromethoxy)-phenylhydrazone - DCCD N,N-dicyclohexylcarbodiimide - TMPD N,N,N,N-tetramethyl-p-phenylenediimide - Q ubiquinone Q     

Vanadyl Causes Hydroxyl Radical Mediated Degradation of Deoxyribose

Vanadyl caused a time- and dose-dependent degradation of deoxyribose to carbonyl products detectable with thiobarbituric acid. This process was inhibited by catalase, ethanol or HEPES; whereas superoxide dismutase was without effect. Vanadate did not substitute for vanadyl even in the presence of a source of O₂^- plus H₂ O ₂; but it did so in the presence of reductants such as thiols or NADH. It appears that hydrogen peroxide, generated by the autoxidation of vanadyl, is reduced by vanadyl to the hydroxyl radical; which, in turn, was responsible for the degradation of deoxyribose. A similar process might contribute to the toxic and pharmacological effects of vanadium salts.     

Chromosome polymorphism in populations of the grasshopper Trimerotropis pallidipennis from southern Argentina

Three populations of the grasshopper Trimerotropis pallidipennis from southern Argentina have been studied cytologically. A very characteristic B-chromosome was found in all three. They also showed geographical variability in respect of the presence of pericentric inversions, and the inversion system was found to influence chiasma frequency. The Laguna Blanca population, which is on the hypothetical pathway the species is believed to have followed during its migration from northern to southern latitudes, has the same karyotype composition as the N. American form, with fixed inversions in the 3 largest autosomes and the X-chromosome. Its members have a high total chiasma frequency and a great number of interstitial chiasmata. The Sierra de la Ventana population, situated at the absolute eastern border of the species distribution is highly polymorphic with respect to the presence of inversions in the medium chromosomes. Its members have the lowest total chiasma frequency and a greatly reduced number of interstitial chiasmata. Situated geographically between the other two, the Choele-Choel population has the highest frequency of inversions and many of them are homozygous. Its members have a higher total chiasma frequency than that observed in specimens from Sierra de la Ventana, and a greatly reduced number of interstitial chiasmata, similar to that observed in individuals from the latter population.     

The investigation of structure–activity relationship of polyamine-targeted synthetic compounds from different chemical groups

Amino Acids - The polyamine (PA) metabolism is involved in cell proliferation and differentiation. Increased cellular PA levels are observed in different types of cancers. Products of PA oxidation...     

Climatic Factors Influencing the Anthrax Outbreak of 2016 in Siberia,Russia

In 2016, an outbreak of anthrax killing thousands of reindeer and affecting dozens of humans occurred on the Yamal peninsula, Northwest Siberia, after 70 years of epidemiological situation without outbreaks. The trigger of the outbreak has been ascribed to the activation of spores due to permafrost thaw that was accelerated during the summer heat wave. The focus of our study is on the dynamics of local environmental factors in connection with the observed anthrax revival. We show that permafrost was thawing rapidly for already 6 years before the outbreak. During 2011–2016, relatively warm years were followed by cold years with a thick snow cover, preventing freezing of the soil. Furthermore, the spread of anthrax was likely intensified by an extremely dry summer of 2016. Concurrent with the long-term decreasing trend in the regional annual precipitation, the rainfall in July 2016 was less than 10% of its 30-year mean value. We conclude that epidemiological situation of anthrax in the previously contaminated Arctic regions requires monitoring of climatic factors such as warming and precipitation extremes.