Progress of researches on symbionts in the management of mosquito-borne infectious diseases / 中国血吸虫病防治杂志

Mosquitoes are the main vectors of many infectious diseases, including malaria and yellow fever, which seriously threaten human health across the world. In addition to the use of chemical insecticides, genetic control is a new attempt to currently available interventions used for mosquito vector control. In terms of ecological safety, however, symbiotic control as a novel approach has been proposed for mosquito control. Since there are multiple symbiotic microflora inhabiting in a variety of tissues of mosquitoes, including the digestive tract, they may affect the transmission of mosquito-borne infectious diseases through affecting the lifespan, reproductive competence, and vector competence of the host. In this review, the interactions between symbionts in mosquitoes were summarized, and the research progress of mosquito-associated symbionts in the management of mosquitoborne infectious diseases was reviewed.

Evidencia molecular de la ocurrencia de bacterias celulolíticas del género Cohnella en especies neotropicales de Nasutitermitinae colectadas en el NEA / Molecular evidence that cellulolytic bacterial genus Cohnella is widespread among Neotropical Nasutitermitinae from NE Argentina

Cohnella is a highly cellulolytic bacterial genus, which can be found in a variety of habitats. The aim of this study was to assess its presence in the digestive tract of termite species collected in North-eastern Argentina: Nasutitermes aquilinus, N. corniger and Cortaritermes fulviceps. Gut homogenates were incubated with cellulosic substrate for bacterial growth. Bacterial 16S rDNA was partially amplified using new primers for Cohnella spp. and cloned. Sequences obtained showed highest similarity (97.2-99.9%) with those of Cohnella spp. previously reported from diverse environments. Phylogenetic analysis tended to group the clones according to their host species and sampling sites. These results indicate the association of Cohnella-related intestinal symbionts with three common Neotropical termites. Their potential industrial application encourages further research.

Cohnella es un género de bacterias celulolíticas que puede ser encontrado en una variedad de hábitats. El propósito de este estudio fue registrar su presencia en el tracto digestivo de termitas (Nasutitermes aquilinus, N. corniger y Cortaritermes fulviceps) colectadas en el noreste argentino (NEA). Se incubaron homogenados de intestinos en sustrato celulósico para multiplicar las bacterias. Utilizando nuevos cebadores para Cohnella spp., se amplificó una porción del ADN ribosomal 16S bacteriano, el cual fue posteriormente clonado. Las secuencias obtenidas mostraron su mayor porcentaje de similitud (97,2-99,9%) con Cohnella spp., previamente reportadas en diversos ambientes. El análisis filogenético tendió a agrupar a los clones de acuerdo a la especie hospedante y al sitio de muestreo. Estos resultados indican que especies de termitas frecuentes en el NEA albergan simbiontes intestinales relacionados con el género Cohnella. Las potenciales aplicaciones industriales de estos microorganismos animan a profundizar los estudios.

Phylogeny of the Trichogramma endosymbiont Wolbachia, an alpha-proteobacteria (Rickettsiae) / Filogenia do endosimbionte Wolbachia em Trichogramma, an alpha-proteobacteria (Rickettsiae)

Abstract Wolbachia (Hertig) endosymbionts are extensively studied in a wide range of organisms and are known to be transmitted through the egg cytoplasm to the offsping. Wolbachia may cause several types of reproductive modifications in arthropods. In Trichogramma species, parthenogenesis-inducing Wolbachia bacteria allow females wasps to produce daughters from unfertilized eggs and these bacteria are present in at least 9% of all Trichogramma species. Phylogenetic studies have led to the subdivision of the Wolbachia clade in five supergroups (A, B, C, D and E) and Wolbachia from Trichogramma belong to supergroup B. Here, using the wsp gene, four groups of Wolbachia that infect Trichogramma species were distinguished and the addition of a new group "Ato" was suggested due to the addition of Wolbachia from Trichogramma atopovirilia (Oatman and Platner). Specific primers were designed and tested for the "Ato" group. Seventy-five percent of all evaluated Wolbachia strains from Trichogramma fell within "Sib" group.

Resumo Endosimbiontes do gênero Wolbachia (Hertig) são extensivamente estudados em uma ampla gama de organismos e são conhecidos por serem transmitidos via citoplasma do ovo hospedeiro para seu descendente. Wolbachia pode causar vários tipos de alterações reprodutivas nos artrópodes. Nas espécies de Trichogramma, a reprodução partenogenética induzida por Wolbachia, possibilita as fêmeas dos parasitoides a produção de fêmeas a partir de ovos não fertilizados e estas bactérias estão presentes em pelo menos 9% de todas as espécies de Trichogramma. Estudos filogenéticos têm levado a subdivisão do clado Wolbachia em cinco supergrupos (A, B, C, D and E). Wolbachia em Trichogramma pertence ao supergrupo B. Com o gene wsp foi possível se distinguir quatro grupos de Wolbachia que infectam Trichogramma e adicionar um novo grupo (Ato) devido a inclusão de Wolbachia detectada em Trichogramma atopovirilia (Oatman and Platner, 1983). Primers específicos foram construídos e testados para o grupo "Ato". Setenta e cinco por cento de todas as linhagens de Wolbachia que infectam Trichogramma se enquadraram dentro do grupo "Sib".

Phylogeny of the Trichogramma endosymbiont Wolbachia, an alpha-proteobacteria (Rickettsiae)

Abstract Wolbachia (Hertig) endosymbionts are extensively studied in a wide range of organisms and are known to be transmitted through the egg cytoplasm to the offsping. Wolbachia may cause several types of reproductive modifications in arthropods. In Trichogramma species, parthenogenesis-inducing Wolbachia bacteria allow females wasps to produce daughters from unfertilized eggs and these bacteria are present in at least 9% of all Trichogramma species. Phylogenetic studies have led to the subdivision of the Wolbachia clade in five supergroups (A, B, C, D and E) and Wolbachia from Trichogramma belong to supergroup B. Here, using the wsp gene, four groups of Wolbachia that infect Trichogramma species were distinguished and the addition of a new group Ato was suggested due to the addition of Wolbachia from Trichogramma atopovirilia (Oatman and Platner). Specific primers were designed and tested for the Ato group. Seventy-five percent of all evaluated Wolbachia strains from Trichogramma fell within Sib group.

Resumo Endosimbiontes do gênero Wolbachia (Hertig) são extensivamente estudados em uma ampla gama de organismos e são conhecidos por serem transmitidos via citoplasma do ovo hospedeiro para seu descendente. Wolbachia pode causar vários tipos de alterações reprodutivas nos artrópodes. Nas espécies de Trichogramma, a reprodução partenogenética induzida por Wolbachia, possibilita as fêmeas dos parasitoides a produção de fêmeas a partir de ovos não fertilizados e estas bactérias estão presentes em pelo menos 9% de todas as espécies de Trichogramma. Estudos filogenéticos têm levado a subdivisão do clado Wolbachia em cinco supergrupos (A, B, C, D and E). Wolbachia em Trichogramma pertence ao supergrupo B. Com o gene wsp foi possível se distinguir quatro grupos de Wolbachia que infectam Trichogramma e adicionar um novo grupo (Ato) devido a inclusão de Wolbachia detectada em Trichogramma atopovirilia (Oatman and Platner, 1983). Primers específicos foram construídos e testados para o grupo Ato. Setenta e cinco por cento de todas as linhagens de Wolbachia que infectam Trichogramma se enquadraram dentro do grupo Sib.

Amphidinolide P from the Brazilian octocoral Stragulum bicolor

Abstract Dinoflagellates are an important source of unique bioactive secondary metabolites. Symbiotic species, commonly named zooxanthellae, transfer most of their photosynthetically fixed carbon to their host. The mutualistic relationship provides the organic metabolites used for energy production but there are very few reports of the role of the dinoflagellates in the production of secondary metabolites in the symbiotic association. Corals and other related cnidarians are the most well-known animals containing symbiotic dinoflagellates. In the present paper we describe the isolation of amphidinolide P (1) from the octocoral Stragulum bicolor and its prey, the nudibranch Marionia limceana, collected off the coasts of Fortaleza (Ceará, Brazil). The coral extracts also contained 3-O-methyl derivative (2) of amphidinolide P, together with minor compounds still under investigation. Amphidinolides have been so far reported only in laboratory cultures of Amphidinium sp., thus compounds 1 and 2 represents the first identification of these polyketides in invertebrates. The finding proves the possibility to isolate amphidinolides from a natural symbiosis, enabling further biological and biotechnological studies.

Desenvolvimento ovariano e influência da cópula na maturação dos ovários de Diaphorina citri Kuwayama (Hemiptera: Psyllidae) / Ovarian development and analysis of mating effects on ovary maturation of Diaphorina citri Kuwayama (Hemiptera: Psyllidae)

As many other insects with a restricted diet, the citrus psyllid Diaphorina citri Kuwayama, which vector the causing agent of the Huanglongbing, the bacteria Candidatus Liberibacter spp., is intimately associated with symbiotic microorganisms. These mutualist symbionts play a key role on their host nutritional ecology, and are vertically transmitted to the progeny. However, despite the role symbionts play on host development and reproduction, and the growing opportunities of exploitation of the association insect-symbiont to control insect vectored-pathogens, there are very few studies on the host reproductive biology and on the symbiont transovarial transmission. Therefore, we aimed at analyzing the ovary development during D. citri adulthood, and at verifying for the mating requirement as a trigger to initiate ovary development. Newly-emerged D. citri females were grouped as virgin or mated and ovary development was observed during adulthood. Newly-emerged females have immature ovaries, and ovaries remain without any mature eggs until females mate. Once female mates, the vitellogenesis synthesis and uptake are estimulated, and oocytes are quickly developed. Oocytes maturation in ovarioles is metachronic, with only one oocyte developing at a time in each oogenic cycle. Morphological observations of the reproductive system including the ovaries and spermatheca, after the first cluster of eggs is laid, indicated D. citri is polyandrous, and may require multiple mating to develop additional oogenic maturation cycles.

Habitat preference of Zoantharia genera depends on host sponge morphology / La preferencia de hábitat de géneros de Zoantharia depende de la morfología de la esponja / A preferência de habitat de gêneros do Zoantharia depende da morfologia da esponja

Objective. Studies about sponge-zoanthid symbioses have been focused on understanding the specificity of the association, rather than testing what are the characteristics that make the host suitable to be colonized. For the first time it is investigated whether the Zoantharia Parazoanthus and Epizoanthus preference is related to the host sponge morphology (shape and mechanical resistance). Materials and methods. Sponges were categorized according to their shape and mechanical resistance. The presence/absence of zoanthids was recorded in 1,068 sponges at San Andres Island, and their habitat preference was evaluated using indices and confidence intervals. Results. 85 Parazoanthus colonies (78% of the total associations) and 24 Epizoanthus colonies (22%) were associated to sponges (10.2% in total). Parazoanthus uses branched and compressible sponges although prefers encrusting and fragile sponges, while Epizoanthus showes the opposite pattern, it can inhabit encrusting and fragile sponges but prefers branched and compressible sponges. Conclusion. These results indicated that sponge morphology is an important trait in zoanthid habitat selection. On the other hand, the similarity in the habitat used by zoanthids suggests the possibility of inter-generic competition if common resources are limited in time and space, while the differential habitat preference allows the competitive coexistence of both genera.

Objetivo. Los estudios sobre la simbiosis entre zoantídeos y esponjas se han centrado en la comprensión de la especificidad de la asociación, en lugar de explorar cuáles son las características que hacen que un huésped sea adecuado para ser colonizado. Por primera vez se investiga si en los Zoantharia Parazoanthus y Epizoanthus la preferencia está relacionada con la morfología de la esponja hospedera (forma y resistencia mecánica). Materiales y métodos. Las esponjas fueron categorizadas según su forma y resistencia mecánica. La presencia/ausencia de zoantídeos se registró en 1.068 esponjas en la Isla de San Andrés y la preferencia de hábitat se evaluó utilizando diferentes índices e intervalos de confianza. Resultados. 85 colonias de Parazoanthus (78% del total de asociaciones) y 24 colonias de Epizoanthus (22%) se encontraron asociadas a esponjas (10,2% en total). Parazoanthus usó esponjas ramificadas y compresibles, pero prefirió las incrustantes y frágiles; mientras que Epizoanthus demostró el patrón contrario, habitando en las esponjas incrustantes y frágiles, pero prefiriendo las esponjas ramificadas y compresibles. Conclusión. Estos resultados indican que la morfología de las esponjas es un aspecto importante para la selección de hábitat por parte del zoantídeo. Por otra parte, la similitud en el hábitat usado por los zoantídea sugiere la posibilidad de competencia entre géneros si los recursos que comparten llegan a ser limitantes en tiempo y espacio; mientras que, la diferencia en la preferencia de hábitat permitiría la coexistencia competitiva de ambos géneros.

Objetivo. O estudo sobre a simbiose entre zoantídeos e esponjas têm-se centrado na compreensão da especificidade da associação, em vez de explorar quais são as características que tornam ao hospedeiro adequado a ser colonizado. Pela primeira vez se pesquisa nos Zoantharia, Parazoanthus e Epizoanthus, se a preferência está relacionada com a morfologia da esponja hospedeira (forma e resistência mecânica). Materiais e métodos. As esponjas foram classificadas de acordo com a sua forma e resistência mecânica. A presença/ausência de zoantídeos foi registrada em 1.068 esponjas na ilha de San Andres e a preferência de habitat foi avaliada através de diferentes índices e intervalos de confiança. Resultados. 85 Parazoanthus (78% do total das associações) e 24 Epizoanthus (22%) foram encontradas associadas com esponjas (10,2% do total). Parazoanthus utilizou esponjas ramificadas e compressíveis, mas preferiu as incrustantes e frágeis; enquanto Epizoanthus demonstrou o padrão oposto, habitando nas esponjas incrustantes e frágeis, mas preferindo as esponjas ramificadas e compressíveis. Conclusão. Estes resultados indicam que a morfologia das esponjas é um aspecto importante na seleção do habitat pelos zoantídeos. Além disso, a semelhança do habitat utilizado pelos zoantídeos sugere a possibilidade de competição inter- gêneros se os recursos compartilhados são limitantes no tempo e no espaço; enquanto que, a diferença na preferência de habitat permitiria a coexistência competitiva de ambos os gêneros.

Physiological traits of the symbiotic bacterium Teredinibacter turnerae isolated from the mangrove shipworm Neoteredo reynei

Nutrition in the Teredinidae family of wood-boring mollusks is sustained by cellulolytic/nitrogen fixing symbiotic bacteria of the Teredinibacter clade. The mangrove Teredinidae Neoteredo reynei is popularly used in the treatment of infectious diseases in the north of Brazil. In the present work, the symbionts of N. reynei, which are strictly confined to the host's gills, were conclusively identified as Teredinibacter turnerae. Symbiont variants obtained in vitro were able to grow using casein as the sole carbon/nitrogen source and under reduced concentrations of NaCl. Furthermore, cellulose consumption in T. turnerae was clearly reduced under low salt concentrations. As a point of interest, we hereby report first hand that T. turnerae in fact exerts antibiotic activity. Furthermore, this activity was also affected by NaCl concentration. Finally, T. turnerae was able to inhibit the growth of Gram-negative and Gram-positive bacteria, this including strains of Sphingomonas sp., Stenotrophomonas maltophilia, Bacillus cereus and Staphylococcus sciuri. Our findings introduce new points of view on the ecology of T. turnerae, and suggest new biotechnological applications for this marine bacterium.

The Mechanism of Signal Recognition and Transduction in the Establishment of Mycorrhizal Associations / 微生物学通报

Multiplicity of signals and diversity of signaling pathways exist during the establishment of mycorrhizal associations together with the regulation of symbiosis-specific genes expression.This mechanism of signal recognition and transduction related with development process of the symbiont was reviewed at the molecular level.