Activity of Mg2+-ATPase and cytochrome c-Oxidase in microsporocytes and anther wall during microsporogenesis inLarix europaea D.C.

Studies have been made on the activity of two mitochondrial enzymes, Mg²⁺ ATPase (E.C.3.6.1.3.) and cytochrome c-oxidase (E.C.I.9.3.2.) in microsporocytes and somatic cells of anther in larch. The material for study were homogeneous fractions of microsporocytes from 15 stages of meiosis and the attendant anther somatic cells. The results have demonstrated that cells undergoing meiosis exhibit considerable mitochondrial metabolic activity. It is characterized by considerable variations in the activity level of both enzymes studied. The level and dynamics of variations of Mg²⁺-ATPase and cytochrome c-oxidase activity in microsporocytes are clearly different from those in the anther somatic cells. The cytochrome c-oxidase activity in microsporocytes throughout microsporogenesis is higher compared with that in the anther wall cells, whereas the Mg²⁺-ATPase activity in microsporocytes averagesca. one half that in the anther somatic cells The dynamics of activity variations of the enzymes under study suggests enhanced mitochondrial metabolism in the period of middle diplotene and young dyad. This result supports the thesis following from our earlier studies that the middle diplotene and young dyad constitute specific metabolic switches in microsporogenesis in larch.     

Juvenile hormone esterases of Lepidoptera

Summary The juvenile hormone esterase (JHE) titer was measured during the last larval instar of 11 species of Lepidoptera (Pieris rapae, Junonia coenia, Danaus plexippus, Hemileuca nevadensis, Pectinophora gossypiella, Spodoptera exigua, Orgyia vetusta, Ephestia elutella, Galleria mellonella, Manduca sexta andEstigmene acrea). All species had a peak of JHE at or near the time of wandering. The peak activity at this time ranged from 0.8 to 388 nmoles JH III cleaved/min·ml. All species exceptJ. coenia had a second peak of JHE during the late prepupal stage. The height of the second peak ranged from 0.4 to 98.4 nmoles/min·ml. However, there was no apparent correlation between size of the first and second JHE activity peaks for the lepidopteran species examined. There was an apparent relationship between the height of the first and second JHE peaks and reports on titer of JH just prior to these peaks. These data support, with some qualifications, the extension of developmental information obtained on several well studied species to a variety of Lepidoptera.Abbreviations JH juvenile hormone - JHE juvenile hormone esierase - PTTH prothoracotropic hormone - R _o -10-3108 1-(4-ethylphenoxy)-6,7-epoxy-3-ethyl-7-methylnonane     

Large BRCA1 and BRCA2 genomic rearrangements in Polish high-risk breast and ovarian cancer families

BRCA1 and BRCA2 are two major genes associated with familial breast and ovarian cancer susceptibility. In Poland standard BRCA gene test is usually limited to Polish founder BRCA1 mutations: 5382insC, C61G and 4153delA. To date, just a few single large genomic rearrangements (LGRs) of BRCA1 gene have been reported in Poland. Here we report the first comprehensive analysis of large mutations in BRCA1 and BRCA2 genes in this country. We screened LGRs in BRCA1 and BRCA2 genes by multiplex ligation-dependent probe amplification in 200 unrelated patients with strong family history of breast/ovarian cancers and negative for BRCA1 Polish founder mutations. We identified three different LGRs in BRCA1 gene: exons 13-19 deletion, exon 17 deletion and exon 22 deletion. No LGR was detected in BRCA2 genes. Overall, large rearrangements accounted for 3.7 % of all BRCA1 mutation positive families in our population and 1.5 % in high-risk families negative for Polish founder mutation.     

Characterization of reemerging chikungunya virus

An unprecedented epidemic of chikungunya virus (CHIKV) infection recently started in countries of the Indian Ocean area, causing an acute and painful syndrome with strong fever, asthenia, skin rash, polyarthritis, and lethal cases of encephalitis. The basis for chikungunya disease and the tropism of CHIKV remain unknown. Here, we describe the replication characteristics of recent clinical CHIKV strains. Human epithelial and endothelial cells, primary fibroblasts and, to a lesser extent, monocyte-derived macrophages, were susceptible to infection and allowed viral production. In contrast, CHIKV did not replicate in lymphoid and monocytoid cell lines, primary lymphocytes and monocytes, or monocyte-derived dendritic cells. CHIKV replication was cytopathic and associated with an induction of apoptosis in infected cells. Chloroquine, bafilomycin-A1, and short hairpin RNAs against dynamin-2 inhibited viral production, indicating that viral entry occurs through pH-dependent endocytosis. CHIKV was highly sensitive to the antiviral activity of type I and II interferons. These results provide a general insight into the interaction between CHIKV and its mammalian host.     

IgG and IgA immunoglobulins in helicobacter pylori infections of children with chronic dyspepsia before and after two week triple drug therapy

The aim of this study was to investigate whether serological techniques, ELISA and Western blot, are useful in monitoring treatment of H. pylori-associated chronic dyspeptic symptoms in children. We observed a correlation between a decrease in the anti-H. pylori IgG titer and an effective treatment. So, our results suggested that the ELISA assay conducted with a glycine H. pylori extract can be a good noninvasive assay for monitoring the effectiveness of the therapy. By using the Western blot method, we showed some variation in the specificity of anti-H. pylori IgG produced before and after treatment. However, this variation was not correlated with the effectiveness of the therapy.     

Anti-Lewis X IgM and IgG in H. pylori infections in children and adults

A role of autoimmune processes in the pathology of Helicobacter pylori infections has been suggested. The Lewis determinants present in LPS molecule of H. pylori bacteria have been indicated as the cause of antigenic mimicry. In this study, the prevalence of IgM and IgG antibodies to Lewis X antigen in the sera from children and adults, with or without dyspepsia, infected or not infected with H. pylori, seropositive and seronegative for anti-H. pylori IgG were determined immuno-enzymatically (ELISA). Our results revealed that humans may produce anti-Lewis X antibodies, particularly of IgM class, in the absence of H. pylori infection or H. pylori independent dyspepsia. The production of such antibodies, by healthy children who had never been infected with H. pylori suggested that anti-Lewis X antibodies may occur naturally.     

Mitochondrial Respiratory Chain Complex Patterns from Acanthamoeba castellanii and Lycopersicon esculentum: Comparative Analysis by BN-PAGE and Evidence of Protein–Protein Interaction Between Alternative Oxidase and Complex III

We have previously shown that a kinetic interplay exists between the cytochrome pathway and the alternative oxidase in mitochondria from amoeba Acanthamoeba castellanii . Native interaction analyses using blue native gel electrophoresis coupled to denaturating electrophoresis and immunodetection have indicated associations between alternative oxidase and oxidative phosphorylation complexes in both amoeba and tomato mitochondria. These associations are dependent on the expression level of alternative oxidase according to the physiological state in both organisms. Alternative oxidase associates broadly with large complexes of the respiratory chain when it is expressed in large amount, i.e., in ripe tomato and exponentially growing amoeba. On the contrary, alternative oxidase interacts specifically with complex III even if expression of the oxidase is low, i.e., in green tomato and stationary phase amoeba. This specific interaction represents a higher level of regulation driven by protein-protein interactions leading to a direct kinetic interplay between the cytochrome pathway and alternative oxidase in both plant and amoeba mitochondria.