Hybridization and introgression of the genomes of Drosophila nasuta and Drosophila albomicans: evolution of new karyotypes.

Drosophila nasuta (2n = 8) and Drosophila albomicans (2n = 6) are cross-fertile allopatric sibling chromosomal races of the nasuta subgroup of Drosophila. Hybrids of these races can be maintained for any number of generations. Some of the introgressed hybrid lineages of D. nasuta and D. albomicans, after passing through a transient phase of karyotypic polymorphism, ended up with a stable karyotype whose composition is different from those of the parental races. Such hybrid populations were called cytoraces, in which the chromosomes of D. nasuta and D. albomicans are represented in different combinations. The karyotypic composition of 16 such cytoraces have been presented and discussed with reference to evolutionary strategies such as balancing selection, directional selection, and sex-specific effect on different components of the evolving karyotypes.     

Molecular diagnosis of apple virus and viroid pathogens from India

Apple is known to be susceptible to various virus and viroid pathogens. Symptomatic apple cultivars and rootstocks were collected and analyzed by ELISA and then through RT-PCR. The study reports the presence of Apple mosaic virus (ApMV), Apple stem grooving virus (ASGV), Apple stem pitting virus (ASPV), Apple chlorotic leaf spot virus (ACLSV), the major apple viruses and Prunus necrotic ringspot virus (PNRSV), a minor apple virus, at the molecular level in India. Apple scar skin viroid (ASSVd) infection was also confirmed at the molecular level. Sporadic incidences of Tomato ringspot virus and Arabis mosaic virus infections were also detected by ELISA in nursery plants.     

Nuclear Localization of the Mitochondrial Factor HIGD1A during Metabolic Stress

Cellular stress responses are frequently governed by the subcellular localization of critical effector proteins. Apoptosis-inducing Factor (AIF) or Glyceraldehyde 3-Phosphate Dehydrogenase (GAPDH), for example, can translocate from mitochondria to the nucleus, where they modulate apoptotic death pathways. Hypoxia-inducible gene domain 1A (HIGD1A) is a mitochondrial protein regulated by Hypoxia-inducible Factor-1α (HIF1α). Here we show that while HIGD1A resides in mitochondria during physiological hypoxia, severe metabolic stress, such as glucose starvation coupled with hypoxia, in addition to DNA damage induced by etoposide, triggers its nuclear accumulation. We show that nuclear localization of HIGD1A overlaps with that of AIF, and is dependent on the presence of BAX and BAK. Furthermore, we show that AIF and HIGD1A physically interact. Additionally, we demonstrate that nuclear HIGD1A is a potential marker of metabolic stress in vivo, frequently observed in diverse pathological states such as myocardial infarction, hypoxic-ischemic encephalopathy (HIE), and different types of cancer. In summary, we demonstrate a novel nuclear localization of HIGD1A that is commonly observed in human disease processes in vivo.     

Cancer incidence and mortality in people aged less than 75 years: Changes in Australia over the period 1987–2007

BackgroundAustralia has one of the highest rates of cancer incidence worldwide and, despite improving survival, cancer continues to be a major public health problem. Our aim was to provide simple summary measures of changes in cancer mortality and incidence in Australia so that progress and areas for improvement in cancer control can be identified.MethodsWe used national data on cancer deaths and newly registered cancer cases and compared expected and observed numbers of deaths and cases diagnosed in 2007. The expected numbers were obtained by applying 1987 age–sex specific rates (average of 1986–1988) directly to the 2007 population. The observed numbers of deaths and incident cases were calculated for 2007 (average of 2006–2008). We limited the analyses to people aged less than 75 years.ResultsThere was a 28% fall in cancer mortality (7827 fewer deaths in 2007 vs. 1987) and a 21% increase in new cancer diagnoses (13,012 more diagnosed cases in 2007). The greatest reductions in deaths were for cancers of the lung in males (?2259), bowel (?1797), breast (?773) and stomach (?577). Other notable falls were for cancers of the prostate (?295), cervix (?242) and non-Hodgkin lymphoma (?240). Only small or no changes occurred in mortality for cancers of the lung (female only), pancreas, brain and related, oesophagus and thyroid, with an increase in liver cancer (267). Cancer types that showed the greatest increase in incident cases were cancers of the prostate (10,245), breast (2736), other cancers (1353), melanoma (1138) and thyroid (1107), while falls were seen for cancers of the lung (?1705), bladder (?1110) and unknown primary (?904).ConclusionsThe reduction in mortality indicates that prevention strategies, improvements in cancer treatment, and screening programmes have made significant contributions to cancer control in Australia since 1987. The rise in incidence is partly due to diagnoses being brought forward by technological improvements and increased coverage of screening and early diagnostic testing.     

Hydrophobicity and surface electrostatic charge of conidia of the mycoparasitic <Emphasis Type="Italic">Trichoderma</Emphasis> species

The present investigation was done to understand the fungal-fungal interactions mechanisms based on level of nonspecific adhesion of a potential fungal mycoparasite (Trichoderma) to their fungal host (Macrophomina phaseolina). The relative cell surface hydrophobicity (CSH) and cell surface electrostatic charge (CSEC) of 29 isolates of Trichoderma species, analyzed by bacterial adhesion to hydrocarbon (BATH), hydrophobic interaction chromatography (HIC), microelectrophoresis and contact angle, revealed a large degree of variability. CSH and CSEC of conidia depended on culture age, pH and temperature. Maximum CSH and CSEC were recorded in 25–28 °C range, and both declined significantly with increasing temperature. Isolate Trichoderma hazianum (Th)-23/98 expressed surface hydrophobicity at 25–28 °C and hydrophilicity at 40 °C. Surface hydrophobicity of the isolate was susceptible to various proteases (trypsin, pepsin, proteinase k and a-chymotrypsin) and inhibitors (SDS, mercaptoethanol and Triton X-100) and a significant reduction in CSH was recorded in hydrophobic conidia. Hydrophilic conidia remained more or less unaffected by such treatments. SDS-PAGE analysis of the hydrophobic and hydrophilic conidia exhibited several protein bands in the 25 to 61 kDa range. However, each protein population contained one protein that was not observed in the other population. For hydrophobic conidia, the unique protein had an apparent molecular mass of 49 kDa, while the unique protein associated with hydrophilic conidia had a molecular mass of 61 kDa. Our findings suggest that CSH and CSEC of mycoparasitic Trichoderma may contribute to non-specific adhesion on to the sclerotial surfaces of Macrophomina phaseolina that may be influenced by growth and environmental conditions.     

CD4+ T cells mediate abscess formation in intra-abdominal sepsis by an IL-17-dependent mechanism

Abscess formation associated with intra-abdominal sepsis causes severe morbidity and can be fatal. Previous studies have implicated T cells in the pathogenesis of abscess formation, and we have recently shown that CD4(+) T cells activated in vitro by zwitterionic capsular polysaccharides from abscess-inducing bacteria such as Staphylococcus aureus and Bacteroides fragilis initiate this host response when transferred to naive rats. In this study, we show that mice deficient in alphabetaTCR-bearing T cells or CD4(+) T cells fail to develop abscesses following challenge with B. fragilis or abscess-inducing zwitterionic polysaccharides, compared with CD8(-/-) or wild-type animals. Transfer of CD4(+) T cells from wild-type mice to alphabetaTCR(-/-) animals reconstituted this ability. The induction of abscesses required T cell costimulation via the CD28-B7 pathway, and T cell transfer experiments with STAT4(-/-) and STAT6(-/-) mice demonstrated that this host response is dependent on STAT4 signaling. Significantly higher levels of IL-17, a proinflammatory cytokine produced almost exclusively by activated CD4(+) T cells, were associated with abscess formation in Th2-impaired (STAT6(-/-)) mice, while STAT4(-/-) mice had significantly lower levels of this cytokine than control animals. The formation of abscesses was preceded by an increase in the number of activated CD4(+) T cells in the peritoneal cavity 24 h following bacterial challenge. Confocal laser-scanning microscopy analysis revealed that CD4(+) T cells comprise the abscess wall in these animals and produce IL-17 at this site. Administration of a neutralizing Ab specific for IL-17 prevented abscess formation following bacterial challenge in mice. These data delineate the specific T cell response necessary for the development of intra-abdominal abscesses and underscore the role of IL-17 in this disease process.     

Incipient sexual isolation in the nasuta-albomicans complex of Drosophila: mating preference in male-, female- and multiple-choice mating experiments

Interracial divergence is an important facet of speciation. Thenasuta-albomicans complex ofDrosophila with sixteen morphologically identical, karyotypically different but cross-fertile races is an excellent system to study a few dimensions of raciation.Drosophila nasuta nasuta, Drosophila nasuta albomicans, Cytorace 1, Cytorace 2, Cytorace 3 and Cytorace 4 of this subgroup have been subjected to male-, female- and multiple-choice mating experiments. Out of 8456 crosses conducted, 7185 had successful matings. The overall impression is that mating is far from random amongst these six closely related races of thenasuta-albomicans complex. The males ofD. n. albomicans, Cytorace 1 and Cytorace 4 in male-choice, the females of Cytorace 1 and Cytorace 2 in female-choice, and the males and females ofD. n. nasuta, D. n. albomicans, Cytorace 1 and Cytorace 4 against the males and females of Cytorace 2 in multiple-choice experiments, had significantly more homogamic matings than expected. Thus in this study of evolutionary experimentation on raciation under laboratory conditions, we have documented the initiation of preference for con-specific matings among closely related and independently evolving members of thenasuta-albomicans complex ofDrosophila.     

Suppression of Human T Cell Proliferation Mediated by the Cathepsin B Inhibitor,z-FA-FMK Is Due to Oxidative Stress

The cathepsin B inhibitor, benzyloxycarbonyl-phenylalanine-alanine-fluoromethyl ketone (z-FA-FMK) readily inhibits anti-CD3-induced human T cell proliferation, whereas the analogue benzyloxycarbonyl-phenylalanine-alanine-diazomethyl ketone (z-FA-DMK) had no effect. In contrast, benzyloxycarbonyl-phenylalanine-alanine-chloromethyl ketone (z-FA-CMK) was toxic. The inhibition of T cell proliferation mediated by z-FA-FMK requires not only the FMK moiety, but also the benzyloxycarbonyl group at the N-terminal, suggesting some degree of specificity in z-FA-FMK-induced inhibition of primary T cell proliferation. We showed that z-FA-FMK treatment leads to a decrease in intracellular glutathione (GSH) with a concomitant increase in reactive oxygen species (ROS) levels in activated T cells. The inhibition of anti-CD3-induced T cell proliferation mediated by z-FA-FMK was abolished by the presence of low molecular weight thiols such as GSH, N-acetylcysteine (NAC) and L-cysteine, whereas D-cysteine which cannot be metabolised to GSH has no effect. The inhibition of anti-CD3-induced up-regulation of CD25 and CD69 expression mediated by z-FA-FMK was also attenuated in the presence of exogenous GSH. Similar to cell proliferation, GSH, NAC and L-cysteine but not D-cysteine, completely restored the processing of caspase-8 and caspase-3 to their respective subunits in z-FA-FMK-treated activated T cells. Our collective results demonstrated that the inhibition of T cell activation and proliferation mediated by z-FA-FMK is due to oxidative stress via the depletion of GSH.     

Expression of recombinant Apple chlorotic leaf spot virus coat protein in heterologous system: production and use in immunodiagnosis

Expression condition for maximum recovery of recombinant Apple chlorotic leaf spot virus (ACLSV) coat protein was standardized. The in vitro expressed fusion protein with 6xHis tag (~43 Kd) was purified from inclusion bodies and used as an antigen for raising polyclonal antiserum in rabbit. This antiserum consistently detected ACLSV in pome and stone fruits as well as herbaceous host plants by direct double antibody sandwich enzyme linked immunosorbent assay (DAS-ELISA) and direct tissue blot immunoassay (DTBIA). The conditions for immuno-capture RT-PCR (IC-RT-PCR) were also standardized.