The dead ringer/retained transcriptional regulatory gene is required for positioning of the longitudinal glia in the Drosophila embryonic CNS

The Drosophila dead ringer (dri, also known as retained, retn) gene encodes a nuclear protein with a conserved DNA-binding domain termed the ARID (AT-rich interaction domain). We show here that dri is expressed in a subset of longitudinal glia in the Drosophila embryonic central nervous system and that dri forms part of the transcriptional regulatory cascade required for normal development of these cells. Analysis of mutant embryos revealed a role for dri in formation of the normal embryonic CNS. Longitudinal glia arise normally in dri mutant embryos, but they fail to migrate to their final destinations. Disruption of the spatial organization of the dri-expressing longitudinal glia accounts for the mild defects in axon fasciculation observed in the mutant embryos. Consistent with the late phenotypes observed, expression of the glial cells missing (gcm) and reversed polarity (repo) genes was found to be normal in dri mutant embryos. However, from stage 15 of embryogenesis, expression of locomotion defects (loco) and prospero (pros) was found to be missing in a subset of LG. This suggests that loco and pros are targets of DRI transcriptional activation in some LG. We conclude that dri is an important regulator of the late development of longitudinal glia

Field and Laboratory Evaluation of Bioefficacy of an Insect Growth Regulator (Dimilin) as a Larvicide against Mosquito and Housefly Larvae

The inhibitory function of Dimilin (Diflubenzuron), mostly a chitin synthesis regulator, on the ecdysis of mosquitoes (Anopheles gambiae s.l., Culex quinquefasciatus) and housefly was evaluated in the field and in laboratory. Three formulations of Diflubenzuron were evaluated in this study: Dimilin, Wettable powder (25%), Dimilin granules (2%), and Dimilin tablets (2%). The laboratory and field evaluation used different rates of concentrations of these formulations. Generally, at higher dosages larvae developments, eggs hatchability and pupation were impossible. The development of mosquitoes was significantly higher in control while highly depressed in different dosages of treatment in both laboratory and field experiments. In houseflies, the adult population decreased sharply after treatment of their breeding sites while pupae mortality was noticed to be high in laboratory-treated samples. Dimilin could be opted as one of the choice of the larval control chemicals to be incorporated in the integrated vector control programmes in urban and rural areas

The Drosophila retained/dead ringer gene and ARID gene family function during development

© UBC PressThe recently discovered ARID family of proteins interact with DNA through a phylogenetically conserved sequence termed the A/T Interaction Domain (ARID). The retained/dead ringer (retn/dri) gene of Drosophila melanogaster is a founding member of the ARID gene family, and of the eARID subfamily. This subfamily exhibits an extended region of sequence similarity beyond the core ARID motif and a separate conserved domain termed the REKLES domain. retn/dri is involved in a range of developmental processes, including axis patterning and muscle development. The retn/dri ARID motif has been shown by in vitro studies to exhibit sequence-specific DNA binding activity. Here we demonstrate that the ARID domain is essential for the in vivo function of retn/dri during embryonic development by showing that a mutant form of RETN/DRI, deleted for part of the ARID domain and unable to bind DNA in vitro, cannot rescue the retn/dri mutant phenotype. In the presence of wild-type RETN/DRI this construct acts as a dominant negative, providing additional support for the proposal that RETN/DRI acts in a multiprotein complex. In contrast, we are yet to find an in vivo role for the REKLES domain, despite its clear evolutionary conservation. Finally, we have used germline clone analysis to reveal a requirement for retn/dri in the Drosophila preblastoderm syncytial mitoses.Tetyana Shandala, R. Daniel Kortschak and Robert Sain

The Drosophila dead ringer gene is required for early embryonic patterning through regulation of argos and buttonhead expression

Copyright © 1999 by Company of BiologistsThe dead ringer (dri) gene of Drosophila melanogaster is a member of the recently discovered ARID-box family of eukaryotic genes that encode proteins with a conserved DNA binding domain. dri itself is highly conserved, with specific orthologs in the human, mouse, zebrafish and C. elegans genomes. We have generated dri mutant alleles to show that dri is essential for anterior-posterior patterning and for muscle development in the embryo. Consistent with the mutant phenotype and the sequence-specific DNA-binding properties of its product, dri was found to be essential for the normal early embryonic expression pattern of several key regulatory genes. In dri mutant embryos, expression of argos in the terminal domains was severely reduced, accounting for the dri mutant head phenotype. Conversely, buttonhead expression was found to be deregulated in the trunk region, accounting for the appearance of ectopic cephalic furrows. Curiously, dri was found also to be required for maintenance of expression of the ventrolateral region of even-skipped stripe four. This study establishes dri as an essential co-factor in the regulated expression of specific patterning genes during early embryogenesis

АКТУАЛЬНЫЕ ПРОБЛЕМЫ СОЧЕТАННОГО ПРИМЕНЕНИЯ ПРИВИВОЧНЫХ И НЕИММУНОЛОГИЧЕСКИХ МЕТОДОВ БОРЬБЫ С ИНФЕКЦИЯМИ

Based on data analysis on the morbidity rates and dynamics of the vaccine-preventable infectious diseases in Russia in comparison with those, immune-prophylaxis methods of which have not been developed yet, the need is shown to intensify efforts on generation and application disinfectological technologies and non-specific prophylactic means in addition to the missing vaccinological ones. First of all, this is necessary to control salmonella infections, different hemorrhagic fevers, sexually transmitted diseases, lice and, especially, mass acute respiratory diseases, upper respiratory infections, multiple unrecorded localization and etiology, annual contribution of which to total infection morbidity is 86–93%. Studies and development of this area of prevention and control of «uncontrolled» infections requires efforts both of disinfectologists and professionals in hygiene, epidemiology, microbiology, chemistry, bio-technology, entomology etc. Under these conditions, all infections can and shall become «controlled» through combined application of immunological and non-immunological methods and means generated and assessed on the basis of principles of the evidence-based medicine.На основании анализа данных об уровне и динамике заболеваемости населения России вакцинопрофилактируемыми инфекционными болезнями в сравнении с теми, по которым методы иммунопрофилактики не разработаны, показана необходимость активизации усилий по созданию и применению наряду с еще отсутствующими вакцинологическими также дезинфектологических технологий и средств неспецифической профилактики. Прежде всего это касается сальмонеллезных инфекций, различных геморрагических лихорадок, болезней, передаваемых половым путем, педикулеза и, особенно, массовых острых респираторных заболеваний, инфекций верхних дыхательных путей множественной и неучтенной локализации и этиологии, составляющих ежегодно от 86 до 93% от общей инфекционной заболеваемости. Поиск и разработка в этих направлениях способов борьбы с «неуправляемыми» инфекциями требуют усилий не только специалистов-дезинфектологов, но также ученых-гигиенистов, эпидемиологов, микробиологов, химиков, биотехнологов, энтомологов и др. При таких условиях все инфекции могут и должны стать «управляемыми» при помощи сочетанного применения иммунологических и неиммунологических методов и средств, созидаемых и оцениваемых на основе принципов доказательной медицины.

Citron kinase is an essential effector of the Pbl-activated Rho signalling pathway in Drosophila melanogaster.

Copyright © 2004 The Company of Biologists LtdPebble (Pbl)-activated RhoA signalling is essential for cytokinesis in Drosophila melanogaster. Here we report that the Drosophila citron gene encodes an essential effector kinase of Pbl-RhoA signalling in vivo. Drosophila citron is expressed in proliferating tissues but is downregulated in differentiating tissues. We find that Citron can bind RhoA and that localisation of Citron to the contractile ring is dependent on the cytokinesis-specific Pbl-RhoA signalling. Phenotypic analysis of mutants showed that citron is required for cytokinesis in every tissue examined, with mutant cells exhibiting multinucleate and hyperploid phenotypes. Strong genetic interactions were observed between citron and pbl alleles and constructs. Vertebrate studies implicate at least two Rho effector kinases, Citron and Rok, in cytokinesis. By contrast, we failed to find evidence for a role for the Drosophila ortholog of Rok in cell division. We conclude that Citron plays an essential, non-redundant role in the Rho signalling pathway during Drosophila cytokinesis.Tetyana Shandala, Stephen L. Gregory, Hazel E. Dalton, Masha Smallhorn and Robert Sain

Activity of Cinnamomum Osmophloeum Leaf Essential Oil Against Anopheles gambiae s.s

The increasing status of insecticide resistant mosquitoes in sub-Saharan Africa is a threatening alert to the existing control efforts. All sibling species of An. gambiae complex have evolved insecticide resistance in wild populations for different approved classes of the insecticides currently in use in the field. An alternative compound for vector control is absolutely urgently needed. In this study, the larvicidal activity and chemical composition of the Cinnamomum osmophloeum leaf essential oils were investigated. C. osmophloeum leaf essential oils were extracted by hydrodistillation in a Clevenger-type apparatus for 6 hours, and their chemical compositions identified using GC-MS. These oils were evaluated against An. gambiae s.s. in both laboratory and semi-field situations. The WHO test procedures for monitoring larvicidal efficacy in malaria vectors were used. The composition of C. osmophloeum leaf essential oil has been found to have 11 active compounds. The most abundant compound was trans-cinnamaldehyde (70.20%) and the least abundant was caryophyllene oxide (0.08%). The larvicidal activity was found to be dosage and time dependant both in laboratory and semi-field environments with mortality ranging from 0% to 100%. The LC50 value was found to vary from 22.18 to 58.15 µg/ml in the laboratory while in semi-field environments it was 11.91 to 63.63 µg/ml. The LC90 value was found to range between 57.71 to 91.54 µg/ml in the laboratory while in semi-field environments was 52.07 to 173.77 µg/ml. Mortality ranged from 13% to 100% in the laboratory while in semi-field environments it ranged between 43% to 100% within mortality recording time intervals of 12, 24, 48, and 72 hours. The larvicidal activity shown by C. osmophloeum leaf essential oil is a promising alternative to existing larvicides or to be incorporated in integrated larval source management compounds for An. gambiae s.s control. The efficacy observed in this study is attributed to both major and minor compounds of the essential oils. \u

Effects of resveratrol supplementation on methotrexate chemotherapy-induced bone loss

Intensive cancer chemotherapy is known to cause bone defects, which currently lack treatments. This study investigated the effects of polyphenol resveratrol (RES) in preventing bone defects in rats caused by methotrexate (MTX), a commonly used antimetabolite in childhood oncology. Young rats received five daily MTX injections at 0.75 mg/kg/day. RES was orally gavaged daily for seven days prior to, and during, five-day MTX administration. MTX reduced growth plate thickness, primary spongiosa height, trabecular bone volume, increased marrow adipocyte density, and increased mRNA expression of the osteogenic, adipogenic, and osteoclastogenic factors in the tibial bone. RES at 10 mg/kg was found not to affect bone health in normal rats, but to aggravate the bone damage in MTX-treated rats. However, RES supplementation at 1 mg/kg preserved the growth plate, primary spongiosa, bone volume, and lowered the adipocyte density. It maintained expression of genes involved in osteogenesis and decreased expression of adipogenic and osteoclastogenic factors. RES suppressed osteoclast formation ex vivo of bone marrow cells from the treated rats. These data suggest that MTX can enhance osteoclast and adipocyte formation and cause bone loss, and that RES supplementation at 1 mg/kg may potentially prevent these bone defects.Alice M.C. Lee, Tetyana Shandala, Pei Pei Soo, Yu-Wen Su, Tristan J. King, Ke-Ming Chen, Peter R. Howe and Cory J. Xia