A brief survey of symbiotic Wolbachia in Drosophila / 中国实验动物学报

The symbiotic bacterial species Wolbachia pipientis is a maternally inherited, intracellular parasitic microbe common to arthropod species(including most insects)and some nematodes. This bacteria manipulates the reproduction of its hosts by different mechanisms, including cytoplasmic incompatibility, parthenogenesis inducing, male-killing,feminization and increase female fecundity. In this paper, previous studies on the interactions between Wolbachia and Drosophila is briefly surveyed and discussed.

Rickettsial infection in ticks infesting wild birds from two eco-regions of Argentina / Infecção por riquétsias em carrapatos de aves silvestres em duas ecorregiões da Argentina

Abstract Several tick-borne Rickettsia species are recognized human pathogens in Argentina. Here we evaluated rickettsial infection in ticks collected on passerine birds during 2011-2012 in two eco-regions of Argentina. The ticks were processed by molecular analysis through polymerase chain reaction (PCR) detection and DNA sequencing of fragments of two rickettsial genes, gltA and ompA. A total of 594 tick specimens (532 larvae and 62 nymphs), representing at least 4 species (Amblyomma tigrinum, Ixodes pararicinus, Haemaphysalis juxtakochi, Haemaphysalis leporispalustris), were evaluated. At least one A. tigrinum larva, collected on Coryphospingus cucullatus in Chaco Seco, was infected with Rickettsia parkeri, whereas at least 12 larvae and 1 nymph of I. pararicinus, collected from Troglodytes aedon, Turdus amaurochalinus, Turdus rufiventris, C. cucullatus and Zonotrichia capensis, were infected with an undescribed Rickettsia agent, genetically related to several rickettsial endosymbionts of ticks of the Ixodes ricinus complex. R. parkeri is a recognized human pathogen in several American countries including Argentina, where a recent study incriminated A. tigrinum as the potential vector of R. parkeri to humans. Birds could play an important role in dispersing R. parkeri-infected A. tigrinum ticks. Additionally, we report for the first time a rickettsial agent infecting I. pararicinus ticks.

Resumo Algumas espécies de Rickettsia transmitidas por carrapatos são reconhecidos como patógenos humanos na Argentina. Este presente trabalho avaliou a infecção por Rickettsia em carrapatos coletados em aves passeriformes, durante 2011-2012, em duas ecorregiões da Argentina. Os carrapatos foram processados pela reação em cadeia da polimerase (PCR) e sequenciamento de DNA de dois genes de Rickettsia: gltA e ompA. Ao todo, 594 amostras de carrapatos (532 larvas e 62 ninfas), representando pelo menos 4 espécies (Amblyomma tigrinum, Ixodes pararicinus, Haemaphysalis juxtakochi, Haemaphysalis leporispalustris), foram avaliadas. Pelo menos uma larva de A. tigrinum, coletada de Coryphospingus cucullatus no Chaco Seco, estava infectada com Rickettsia parkeri, enquanto pelo menos 12 larvas e 1 ninfa de I. pararicinus, coletadas de Troglodytes aedon, Turdus amaurochalinus, Turdus rufiventris, C. cucullatus e Zonotrichia capensis estavam infectadas com Rickettsia sp., geneticamente relacionada a vários endossimbiontes riquetsiais de carrapatos do complexo Ixodes ricinus. R. parkeri é reconhecidamente um patógeno humano em alguns países americanos, incluindo a Argentina, onde um estudo recente incriminou A. tigrinum como um provável vetor. Aves poderiam desempenhar um papel importante na dispersão de carrapatos A. tigrinum infectados por R. parkeri. Em adição, relata-se pela primeira vez a infecção por Rickettsia em I. pararicinus.

Wolbachia endosymbiont infection in two Indian butterflies and female-biased sex ratio in the Red Pierrot, Talicada nyseus.

The maternally inherited obligate bacteria Wolbachia is known to infect various lepidopteran insects. However, so far only a few butterfly species harbouring this bacterium have been thoroughly studied. The current study aims to identify the infection status of these bacteria in some of the commonly found butterfly species in India. A total of nine butterfly species belonging to four different families were screened using PCR with Wolbachia-specific wsp and ftsZ primers. The presence of the Wolbachia super group ‘B’ in the butterflies Red Pierrot, Talicada nyseus (Guerin) (Lepidoptera: Lycaenidae) and Blue Mormon, Papilio polymnestor Cramer (Papilionidae), is documented for the first time in India. The study also gives an account on the lifetime fecundity and female-biased sex ratio in T. nyseus, suggesting a putative role for Wolbachia in the observed female-biased sex ratio distortion.

High prevalence and lack of diversity of Wolbachia pipientis in Aedes albopictus populations from Northeast Brazil

The use of Wolbachia as a tool to control insect vectors has recently been suggested. In this context, studies on the prevalence and diversity of this bacterium in wild populations are relevant. Here, we evaluated the diversity of two Wolbachiagenes (ftsZ and wsp) and the prevalence of this endosymbiont in wild Aedes albopictus. Using semi-nested polymerase chain reaction, our results showed that 99.3 percent of the individuals were superinfected with Wolbachia. In regards to genetic diversity, the two genes showed no variation within or among mosquito populations. An analysis of other Wolbachia markers may help to clarify the relationship between insect and endosymbiont.

Endosymbionts of Acanthamoeba Isolated from Domestic Tap Water in Korea

In a previous study, we reported our discovery of Acanthamoeba contamination in domestic tap water; in that study, we determined that some Acanthamoeba strains harbor endosymbiotic bacteria, via our molecular characterization by mitochondrial DNA restriction fragment length polymorphism (Mt DNA RFLP). Five (29.4%) among 17 Acanthamoeba isolates contained endosymbionts in their cytoplasm, as demonstrated via orcein staining. In order to estimate their pathogenicity, we conducted a genetic characterization of the endosymbionts in Acanthamoeba isolated from domestic tap water via 16S rDNA sequencing. The endosymbionts of Acanthamoeba sp. KA/WP3 and KA/WP4 evidenced the highest level of similarity, at 97% of the recently published 16S rDNA sequence of the bacterium, Candidatus Amoebophilus asiaticus. The endosymbionts of Acanthamoeba sp. KA/WP8 and KA/WP12 shared a 97% sequence similarity with each other, and were also highly similar to Candidatus Odyssella thessalonicensis, a member of the alpha-proteobacteria. The endosymbiont of Acanthamoeba sp. KA/WP9 exhibits a high degree of similarity (85-95%) with genus Methylophilus, which is not yet known to harbor any endosymbionts. This is the first report, to the best of our knowledge, to show that Methylophilus spp. can live in the cytoplasm of Acanthamoeba.

Wolbachia in two populations of Melittobia digitata Dahms (Hymenoptera: Eulophidae) / Wolbachia en dos poblaciones de Melittobia digitata Dahms (Hymenoptera: Eulophidae)

We investigated two populations of Melittobia digitata Dahms, a gregarious parasitoid (primarily upon a wide range of solitary bees, wasps, and flies), in search of Wolbachia infection. The first population, from Xalapa, Mexico, was originally collected from and reared on Mexican fruit fly pupae, Anastrepha ludens Loew (Diptera: Tephritidae); the other, from Athens, Georgia, was collected from and reared on prepupae of mud dauber wasps, Trypoxylon politum Say (Hymenoptera: Crabronidae). PCR studies of the ITS2 region corroborated that both parasitoid populations were the same species; this potentially provides a useful molecular taxonomic profile since females of Melittobia species are superficially similar. Amplification of the Wolbachia surface protein gene (wsp) confirmed the presence of this endosymbiont in both populations. Sequencing revealed that the Wolbachia harbored in both populations exhibited a wsp belonging to a unique subgroup (denoted here as Dig) within the B-supergroup of known wsp genes. This new subgroup of wsp may either belong to a different strain of Wolbachia from those previously found to infect Melittobia or may be the result of a recombination event. In either case, known hosts of Wolbachia with a wsp of this subgroup are only distantly related taxonomically. Reasons are advanced as to why Melittobia - an easily reared and managed parasitoid - holds promise as an instructive model organism of Wolbachia infection amenable to the investigation of Wolbachia strains among its diverse hosts.

Se investigaron dos poblaciones de Melittobia digitata Dahms, un parasitoide gregario (principalmente sobre un rango amplio de abejas solitarias, avispas y moscas), en busca de infección por Wolbachia. La primera población, provenía de Xalapa, México, y fue originalmente colectada y criada sobre pupas de la Mosca Mexicana de la Fruta, Anastrepha ludens Loew (Diptera: Tephritidae). La segunda población, originaria de Athens, Georgia, fue colectada y criada sobre prepupas de avispas de barro, Trypoxylon politum Say (Hymenoptera: Crabronidae). Estudios de PCR de la región ITS2 confirmaron que ambas poblaciones del parasitoide pertenecen a la misma especie; lo que nos provee de un perfil molecular taxonómico muy útil debído a que las hembras de las diversas especies de Melittobia son superficialmente similares. La amplificación del gen de superficie de proteina (wsp) de Wolbachia confirmó la presencia de este endosimbionte en ambas poblaciones. La ejecución de la secuencia reveló que Wolbachia alojada en ambas poblaciones exibe un wsp que pertenece a un subgrupo único (denominado aquí como Dig) dentro del supergrupo B de los genes wsp conocidos. Este nuevo subgrupo de wsp podría pertenecer o a un lineaje de Wolbachia de los previamente conocidos infectando a Melittobia o podría ser el resultado de algún evento recombinante. En cualquier caso, los huéspedes conocidos de Wolbachia con un wsp en este subgrupo están relacionados taxonómicamente en forma lejana. Se presentan razones posibles del por qué Melittobia - un parasitoide fácil de criar y manipular - es prometedor como un organismo modelo conveniente para el estudio de líneas de Wolbachia entre diversos huéspedes.

Molecular characterization of bacterial endosymbionts of Acanthamoeba isolates from infected corneas of Korean patients

The endosymbionts of 4 strains of Acanthamoeba (KA/E9, KA/E21, KA/E22, and KA/E23) isolated from the infected corneas of Korean patients were characterized via orcein stain, transmission electron microscopic examination, and 16S rDNA sequence analysis. Double membrane-bound, rod-shaped endosymbionts were distributed randomly throughout both the trophozoites and cysts of each of Acanthamoeba isolates. The endosymbionts of KA/E9, KA/E22, and KA/E23 were surrounded by electron-translucent areas. No lacunae-like structures were observed in the endosymbionts of KA/E21, the bacterial cell walls of which were studded with host ribosomes. Comparative analyses of the 16S rDNA sequences showed that the endosymbionts of KA/E9, KA/E22 and KA/E23 were closely related to Caedibacter caryophilus, whereas the KA/E21 endosymbiont was assigned to the Cytophaga-Flavobacterium-Bacteroides (CFB) phylum. In the 4 strains of Acanthamoeba, the hosts of the endosymbionts were identified as belonging to the Acanthamoeba castellanii complex, which corresponds to the T4 genotype. Acanthamoeba KA/E21 evidenced characteristics almost identical to those of KA/E6, with the exception of the existence of endosymbionts. The discovery of these endosymbionts from Acanthamoeba may prove essential to future studies focusing on interactions between the endosymbionts and the amoebic hosts.

Natural occurrence of Mycobacterium as an endosymbiont of Acanthamoeba isolated from a contact lens storage case

Recent in vitro studies have revealed that a certain Mycobacterium can survive and multiply within freeliving amoebae. It is believed that protozoans function as host cells for the intracellular replication and evasion of Mycobacterium spp. under harmful conditions. In this study, we describe the isolation and characterization of a bacterium naturally observed within an amoeba isolate acquired from a contact lens storage case. The bacterium multiplied within Acanthamoeba, but exerted no cytopathic effects on the amoeba during a 6-year amoebic culture. Trasnmission electron microscopy showed that the bacteria were randomly distributed within the cytoplasm of trophozoites and cysts of Acanthamoeba. On the basis of the results of 18S rRNA gene analysis, the amoeba was identified as A. lugdunensis. A 16S rRNA gene analysis placed this bacterium within the genus Mycobacterium. The bacterium evidenced positive reactivity for acid-fast and fluorescent acid-fast stains. The bacterium was capable of growth on the Middlebrook 7H11-Mycobacterium-specific agar. The identification and characterization of bacterial endosymbionts of free-living protozoa bears significant implications for our understanding of the ecology and the identification of other atypical mycobacterial pathogens.

Studies on the Prokaryotic Expression Conditions of groEL from Endosymbionts in Bemisia tabaci / 微生物学通报

The study on prokaryotic expression conditions of groEL from endosymbiont in B. tabaci was conducted.The results showed that:The optimal IPTG content for inducing prokaryotic expression of groEL was 100?mol/L. When it was induced by IPTG at 35℃,higher GroEL product would be acquired.The optimal induced culturing time for prokaryotic expression of groEL was 4～5 hours.Higher inoculated quantity would benefit prokaryotic expression of groEL. A little NH~+_(4) content would improved prokaryotic expression of groEL, but prokaryotic expression of groEL would be inhibit by Ca~(2+)、Fe~(3+)、K~(+ )and Mg~(2+).When low content glucose was added to the LB medium,it would benefit prokaryotic expression of groEL.Prokaryotic expression of groEL would be inhibit by high content glucose.

A Review on Endosymbionts in Insects / 微生物学通报

Endosymbionts accreted with insects and benefit from each other. Endosymbiont affected the growth, fertilizing and plant disease transmission of insect. At the same time, the symbiosis body was an excellent model for probing into life's origin and evolution. A review was given on the character, distributing in insects, effects on insects and eliminating methods of endosymbionts. The potential values were also discussed.