Effects of Wolbachia-targeted tetracycline on a host-parasitoid-symbiont interaction

The uzifly, Exorista sorbillans (Diptera: Tachinidae), a parasite of the silkworm, Bombyx mori L. (Lepidoptera: Bombycidae), causes heavy losses to the silk industry. This parasitoid harbours a Wolbachia endosymbiont, which controls the fly's reproduction. In the present study a method for curtailing this notorious pest by administering Wolbachia-targeted tetracycline via its silkworm host's diet is investigated. Tetracycline not only influenced the larval growth of the silkworms' by decreasing larval duration, increased silk production and fecundity, without affecting hatchability, it also decreased the reproductive fitness of the uzifly endoparasite by killing the Wolbachia. The antibiotic exerts a beneficial influence by affecting the intestinal flora of silkworm larvae. On the other hand the reproductive fitness of uzifly was greatly reduced in terms of different reproductive abnormalities. When male and female flies that emerged from treated host silkworms were crossed and males from untreated hosts and females from treated hosts were crossed, approximately 72 and 97 of the eggs failed to hatch, respectively. However, of the eggs from crosses between male and female flies that emerged from untreated hosts and between males from treated hosts with females from untreated hosts, an average of 30 failed to hatch and the Wolbachia infection enhanced the fecundity of uziflies. These results demonstrate that the Wolbachia may be essential for uzifly reproduction and that Wolbachia-targeted antibiotics have a beneficial influence on silkworm growth while decreasing the reproductive fitness of the uzifly, E. sorbillans

Effects of Wolbachia in the uzifly, Exorista sorbillans, a parasitoid of the silkworm, Bombyx mori

The uzifly, Exorista sorbillans (Diptera: Tachinidae), a parasitoid of the silkworm, Bombyx mori L. (Lepidoptera: Bombycidae), harbours Wolbachia (Rickettsia) endosymbionts. Administration of 0.05 mg/ml oxytetracycline to the adult uziflies removed Wolbachia endosymbionts and resulted in different reproductive disorders, such as i) reduction in fecundity of uninfected females, ii) cytoplasmic incompatibility in crosses between infected males and uninfected females, iii) sterility in the crosses between both males and females from uninfected populations, and iv) sex-ratio distortion in uninfected females irrespective of the presence of Wolbachia in males. However, tetracycline treatment did not have much effect on longevity of the uzifly. These results suggest that the interaction of Wolbachia with its uzifly host is one of mutual symbiosis as it controls the reproductive physiology of its hosts

Molecular Characterization of Wolbachia and its Phage WO in the Laboratory Populations of Drosophila

Wolbachia are a group of maternally inherited intracellular rickettsial á-proteobacteria, infecting wide range of arthropods and filarial nematodes. They infect around 66% of arthropods and impose various fitness related effects in their host populations to enhance their transmission. In the current study, four out of eight laboratory populations of Drosophila has been found positive for Wolbachia and its phage WO through PCR diagnostics. Four populations of D. ananassae were infected with wRiv strain of Wolbachia and its phage, while other four D. melanogaster populations do not have either of them. Further, phylogenetic characterization of Wolbachia and phage WO from D. ananassae indicates close relationship across other Drosophila species, suggesting possible horizontal transmissio

Wolbachia Association and its Phylogenetic Affiliation of Brugia Malayi Parasites from India

Wolbachia have established a mutualistic association with filarial nematodes and has a phenomenal implication in its normal development, reproduction and survival. Elimination of Wolbachia by tetracycline class of antibiotic compounds have been suggested and successfully implemented for the treatment of lymphatic filarial parasites. Thereby, is necessary to assess the prevalence of the Wolbachia in B. malayi before such new strategies are employed, across the world. In the present communication, the presence of Wolbachia and phylogenetic affiliation in B. malayi collected from Sevagram, Maharashtra, India, has been addressed

Sex ratio distortion in the Nesolynx thymus (Hymenoptera: Eulophidae), an ecto-pupal parasitoid of uzifly, Exorista sorbillans (Diptera: Tachinidae)

The reproductive alterations induced by maternally inherited alpha-proteo-bacteria Wolbachia to their hosts is a well-documented phenomenon. In Nesolynx thymus, a gregarious hymenopterous ecto-pupal parasitoid of the uzifly, Exorista sorbillans, diagnostic PCR assay using specific primers revealed the presence of Wolbachia. Following genetic crossing experiments, we observed a female biased sex ratio of 1 : 9.5 at 25 degrees C and 1 : 3 male to female ratio when the populations were exposed to heat shock 33 degrees C for six hours. Furthermore, we found infection polymorphism, where female parasitoids are infected by Wolbachia but males are not infected. Infected eggs develop into females, whereas uninfected eggs develop parthenogenetically into males. The results are discussed in the context of the possible mechanism of sex-ratio bias caused by Wolbachia

Dependence of the Confinement Time of an Electron Plasma on the Magnetic Field in a Quadrupole Penning Trap

A quadrupole Penning trap is used to confine electrons in weak magnetic fields. Perturbations due to space charge and imperfections in the trap geometry, as well as collisions with the background gas molecules, lead to loss of the electrons from the trap. We present in this work the results on measurements of the electron confinement time and its dependence on the magnetic field in a quadrupolar Penning trap. We describe a method to measure the confinement time of an electron cloud under weak magnetic fields (0.01 T - 0.1 T). This time is found to scale as τ∝B1.41 in variance with the theoretically expected confinement time that scales as τ∝B2 for trapped electrons that are lost through collisions with the neutrals present in the trap. A measurement of the expansion rate of the electron plasma in the trap through controlled variation of the trap voltage, yields expansion times that depend on the energy of escaping electrons. This is found to vary in our case in the scaling range B 0.32 to B 0.43. Distorting the geometry of the trap, results in a marked change in the confinement time's dependence on the magnetic field. The results indicate that the confinement time of the electron cloud in the trap is limited by both, effects of collisions and perturbations that result in the plasma loss through expansion in the trap

Dynamic Scaling in Diluted Systems Phase Transitions: Deactivation trough Thermal Dilution

Activated scaling is confirmed to hold in transverse field induced phase transitions of randomly diluted Ising systems. Quantum Monte Carlo calculations have been made not just at the percolation threshold but well bellow and above it including the Griffiths-McCoy phase. A novel deactivation phenomena in the Griffiths-McCoy phase is observed using a thermal (in contrast to random) dilution of the system.Comment: 4 pages, 4 figures, RevTe

The bronchiolitis season is upon us – recommendations for the management and prevention of acute viral bronchiolitis

Despite being so common, bronchiolitis remains poorly diagnosed and managed. This article is intended as an update on issues pertaining to this condition.http://www.samj.org.zaam201

The bronchiolitis season is upon us – recommendations for the management and prevention of acute viral bronchiolitis

Despite being so common, bronchiolitis remains poorly diagnosed and managed. This article is intended as an update on issues pertaining to this condition.http://www.samj.org.zaam201