RESUMEN

Horizontal gene transfer is widespread in insects bearing intracellular symbionts. Horizontally transferred genes (HTGs) are presumably involved in amino acid synthesis in sternorrhynchan insects. However, their role in insect-symbiont interactions remains largely unknown. We found symbionts Portiera, Hamiltonella and Rickettsia possess most genes involved in lysine synthesis in the whitefly Bemisia tabaci MEAM1 although their genomes are reduced. Hamiltonella maintains a nearly complete lysine synthesis pathway. In contrast, Portiera and Rickettsia require the complementation of whitefly HTGs for lysine synthesis and have lysE, encoding a lysine exporter. Furthermore, each horizontally transferred lysine gene of ten B. tabaci cryptic species shares an evolutionary origin. We demonstrated that Hamiltonella did not alter the titers of Portiera and Rickettsia or lysine gene expression of Portiera, Rickettsia and whiteflies. Hamiltonella also did not impact on lysine levels or protein localization in bacteriocytes harboring Portiera and ovaries infected with Rickettsia. Complementation with whitefly lysine synthesis HTGs rescued E. coli lysine gene knockout mutants. Silencing whitefly lysA in whiteflies harboring Hamiltonella reduced lysine levels, adult fecundity and titers of Portiera and Rickettsia without influencing the expression of Hamiltonella lysA. Furthermore, silencing whitefly lysA in whiteflies lacking Hamiltonella reduced lysine levels, adult fecundity and titers of Portiera and Rickettsia in ovarioles. Therefore, we, for the first time, demonstrated an essential amino acid lysine synthesized through HTGs is important for whitefly reproduction and fitness of both obligate and facultative symbionts, and it illustrates the mutual dependence between whitefly and its two symbionts. Collectively, this study reveals that acquisition of horizontally transferred lysine genes contributes to coadaptation and coevolution between B. tabaci and its symbionts.

Asunto(s)

Evolución Molecular , Transferencia de Gen Horizontal , Halomonadaceae/fisiología , Hemípteros/microbiología , Lisina/metabolismo , Rickettsia/fisiología , Simbiosis , Animales , Hemípteros/genética , Hemípteros/crecimiento & desarrollo , Lisina/genética

RESUMEN

Whiteflies possess bacterial symbionts Candidatus Portiera aleyrodidium that are housed in specialized cells called bacteriocytes and are faithfully transmitted via the ovary to insect offspring. In one whitefly species studied previously, Bemisia tabaci MEAM1, transmission is mediated by somatic inheritance of bacteriocytes, with a single bacteriocyte transferred to each oocyte and persisting through embryogenesis to the next generation. Here, we investigate the mode of bacteriocyte transmission in two whitefly species, B. tabaci MED, the sister species of MEAM1, and the phylogenetically distant species Trialeurodes vaporariorum. Microsatellite analysis supported by microscopical studies demonstrates that B. tabaci MED bacteriocytes are genetically different from other somatic cells and persist through embryogenesis, as for MEAM1, but T. vaporariorum bacteriocytes are genetically identical to other somatic cells of the insect, likely mediated by the degradation of maternal bacteriocytes in the embryo. These two alternative modes of transmission provide a first demonstration among insect symbioses that the cellular processes underlying vertical transmission of bacterial symbionts can diversify among related host species associated with a single lineage of symbiotic bacteria.

Asunto(s)

Halomonadaceae/fisiología , Hemípteros/microbiología , Oocitos/microbiología , Simbiosis , Animales , Herencia

RESUMEN

BACKGROUND: Diaphorina citri is the vector of 'Candidatus Liberibacter asiaticus', the most widespread pathogen associated huanglongbing, the most serious disease of citrus. To enhance our understanding of the distribution and origin of the psyllid, we investigated the genetic diversity and population structures of 24 populations in Asia and one from Florida based on the mtCOI gene. Simultaneously, genetic diversity and population structures of the primary endosymbiont (P-endosymbiont) 'Candidatus Carsonella ruddii' and secondary endosymbiont (S-endosymbiont) 'Candidatus Profftella armatura' of D. citri were determined with the housekeeping genes. RESULT: AMOVA analysis indicated that populations of D. citri and its endosymbionts in east and south-east Asia were genetically distinct from populations in Pakistan and Florida. Furthermore, P-endosymbiont populations displayed a strong geographical structure across east and south-east Asia, while low genetic diversity indicated the absence of genetic structure among the populations of D. citri and its S-endosymbiont across these regions. CONCLUSION: The 'Ca. C. ruddii' is more diverse and structured than the D. citri and the 'Ca. P. armatura' across east and south-east Asia. Multiple introductions of the psyllid have occurred in China. Management application for controlling the pest is proposed based on the genetic information of D. citri and its endosymbionts. © 2017 Society of Chemical Industry.

Asunto(s)

Betaproteobacteria/genética , Variación Genética , Halomonadaceae/genética , Hemípteros/genética , Simbiosis , Animales , Asia Sudoriental , Proteínas Bacterianas/genética , Betaproteobacteria/fisiología , China , Complejo IV de Transporte de Electrones/genética , Florida , Halomonadaceae/fisiología , Hemípteros/microbiología , Proteínas de Insectos/genética , Proteínas Mitocondriales/genética , Pakistán

RESUMEN

An important factor determining the impact of microbial symbionts on their animal hosts is the balance between the cost of nutrients consumed by the symbionts and the benefit of nutrients released back to the host, but the quantitative significance of nutrient exchange in symbioses involving multiple microbial partners has rarely been addressed. In this study on the association between two intracellular bacterial symbionts, "Candidatus Portiera aleyrodidarum" and "Candidatus Hamiltonella defensa," and their animal host, the whitefly Bemisia tabaci, we apply metabolic modeling to investigate host-symbiont nutrient exchange. Our in silico analysis revealed that >60% of the essential amino acids and related metabolites synthesized by "Candidatus Portiera aleyrodidarum" are utilized by the host, including a substantial contribution of nitrogen recycled from host nitrogenous waste, and that these interactions are required for host growth. In contrast, "Candidatus Hamiltonella defensa" retains most or all of the essential amino acids and B vitamins that it is capable of synthesizing. Furthermore, "Candidatus Hamiltonella defensa" suppresses host growth in silico by competition with "Candidatus Portiera aleyrodidarum" for multiple host nutrients, by suppressing "Candidatus Portiera aleyrodidarum" growth and metabolic function, and also by consumption of host nutrients that would otherwise be allocated to host growth. The interpretation from these modeling outputs that "Candidatus Hamiltonella defensa" is a nutritional parasite could not be inferred reliably from gene content alone but requires consideration of constraints imposed by the structure of the metabolic network. Furthermore, these quantitative models offer precise predictions for future experimental study and the opportunity to compare the functional organization of metabolic networks in different symbioses.IMPORTANCE The metabolic functions of unculturable intracellular bacteria with much reduced genomes are traditionally inferred from gene content without consideration of how the structure of the metabolic network may influence flux through metabolic reactions. The three-compartment model of metabolic flux between two bacterial symbionts and their insect host constructed in this study revealed that one symbiont is structured to overproduce essential amino acids for the benefit of the host, but the essential amino acid production in the second symbiont is quantitatively constrained by the structure of its network, rendering it "selfish" with respect to these nutrients. This study demonstrates the importance of quantitative flux data for elucidation of the metabolic function of symbionts. The in silico methodology can be applied to other symbioses with intracellular bacteria.

Asunto(s)

Enterobacteriaceae/fisiología , Halomonadaceae/fisiología , Hemípteros/microbiología , Simbiosis , Aminoácidos/metabolismo , Animales , Simulación por Computador , Redes y Vías Metabólicas , Interacciones Microbianas , Nitrógeno/metabolismo

RESUMEN

A novel Gram-negative, aerobic, motile marine bacterium, strain S4-41(T), was isolated from mucus of the coral Acropora digitifera from the Andaman Sea. Heterotrophic growth was observed in 0-25 % NaCl, at 15-45 °C and pH 4.5-9. In phylogenetic trees, strain S4-41(T) was grouped within the genus Salinicola but formed a separate branch distant from a cluster composed of Salinicola salarius M27(T) and Salinicola socius SMB35(T). DNA-DNA relatedness between strain S4-41(T) and these reference strains were well below 70 %. Q-9 was the sole respiratory quinone. The DNA G+C content was determined to be 63.6 mol%. Based on a polyphasic analysis, strain S4-41(T) is concluded to represent a novel species in the genus Salinicola for which the name Salinicola acroporae sp. nov. is proposed. The type strain is S4-41(T) (=JCM 30412(T) = LMG 28587(T)). Comparative 16S rRNA analysis of the genera Salinicola, Kushneria, Chromohalobacter and Cobetia revealed the presence of genus specific sequence signatures. Multilocus sequence analysis based on concatenated sequences of rRNAs (16S and 23S) and four protein coding housekeeping genes (atpA, gyrB, secA, rpoD) was found to be unnecessary for phylogenetic studies of the genus Salinicola.

Asunto(s)

Antozoos/microbiología , Halomonadaceae/clasificación , Halomonadaceae/aislamiento & purificación , Tipificación de Secuencias Multilocus/métodos , ARN Ribosómico 16S/genética , Aerobiosis , Animales , Proteínas Bacterianas/genética , Técnicas de Tipificación Bacteriana , Composición de Base , Análisis por Conglomerados , Citosol/química , ADN Bacteriano/química , ADN Bacteriano/genética , ADN Ribosómico/química , ADN Ribosómico/genética , Halomonadaceae/genética , Halomonadaceae/fisiología , Concentración de Iones de Hidrógeno , Locomoción , Datos de Secuencia Molecular , Hibridación de Ácido Nucleico , Filogenia , Quinonas/análisis , ARN Ribosómico 23S/genética , Análisis de Secuencia de ADN , Cloruro de Sodio/metabolismo , Temperatura

RESUMEN

A high-throughput screening system for moderately halophilic phenol-degrading bacteria from various habitats was developed to replace the conventional strain screening owing to its high efficiency. Bacterial enrichments were cultivated in 48 deep well microplates instead of shake flasks or tubes. Measurement of phenol concentrations was performed in 96-well microplates instead of using the conventional spectrophotometric method or high-performance liquid chromatography (HPLC). The high-throughput screening system was used to cultivate forty-three bacterial enrichments and gained a halophilic bacterial community E3 with the best phenol-degrading capability. Halomonas sp. strain 4-5 was isolated from the E3 community. Strain 4-5 was able to degrade more than 94% of the phenol (500 mg · L(-1) starting concentration) over a range of 3%-10% NaCl. Additionally, the strain accumulated the compatible solute, ectoine, with increasing salt concentrations. PCR detection of the functional genes suggested that the largest subunit of multicomponent phenol hydroxylase (LmPH) and catechol 1,2-dioxygenase (C12O) were active in the phenol degradation process.

Asunto(s)

Halomonadaceae/aislamiento & purificación , Halomonadaceae/fisiología , Ensayos Analíticos de Alto Rendimiento/métodos , Fenoles/metabolismo , Tolerancia a la Sal , Aminoácidos Diaminos/metabolismo , Proteínas Bacterianas/genética , Biodegradación Ambiental , Catecol 1,2-Dioxigenasa/genética , Halomonadaceae/genética , Oxigenasas de Función Mixta/genética

RESUMEN

The taxonomic position of a Gram-stain negative, moderately halophilic bacterium, designated NCCP-934(T), was investigated using polyphasic taxonomic approach. The strain NCCP-934(T) was isolated from rhizosphere of a plant (Saccharum spontaneum, family Poaceae) growing in salt mines area in the Karak district of Khyber Pakhtunkhwa Province, Pakistan. Cells of strain NCCP-934(T) are rod shaped and motile. The bacterium is strictly aerobic, can grow at a temperature range of 10-40 °C (optimum at 30-33 °C) and in a pH range of 6.0-10.5 (optimum pH 7.0-9.0). The strain can tolerate 1-30 % (w/v) NaCl (optimal growth occurs in the presence of approximately 3-9 % NaCl). The phylogenetic analysis based on the 16S rRNA gene sequence, showed that strain NCCP-934(T) belongs to the genus Kushneria with the highest sequence similarity to K. marisflavi SW32(T) (98.9 %), K. indalinina CG2.1(T) (98.7 %), K. avicenniae MW2a(T) (98.4 %) and less than 97 % similarity with other related species (94.7 % with the type species of the genus, K. aurantia A10(T)). DNA-DNA relatedness between strain NCCP-934(T) and the type strains of the closely related species was lower than 18 %. The chemotaxonomic data (major respiratory quinone, Q9; predominant fatty acids, C18:1 ω7c and C16:0 followed by C12:0 3-OH and Summed features 3 (C16:1 ω7c/iso-C15:0 2-OH); major polar lipids, diphosphatidylglycerol, phosphatidylglycerol, phosphatidylmonomethylethanol, phosphatidylserine, phosphatidylinositol and three polar lipid of unknown structure) supported the affiliation of strain NCCP-934(T) within the genus Kushneria. The DNA G+C content of strain NCCP-934(T) was 59.2 mol%. On the basis of phenotypic, chemotaxonomic and phylogenetic data, strain NCCP-934(T) can be distinguished from the closely related taxa and thus represents a novel species in the genus Kushneria, for which the name Kushneria pakistanensis sp. nov. is proposed, with the type strain NCCP-934(T) (=LMG 28525(T) = KCTC 42082(T) = JCM 18802(T)).

Asunto(s)

Halomonadaceae/clasificación , Halomonadaceae/aislamiento & purificación , Microbiología del Suelo , Aerobiosis , Técnicas de Tipificación Bacteriana , Composición de Base , Análisis por Conglomerados , Citosol/química , ADN Bacteriano/química , ADN Bacteriano/genética , ADN Ribosómico/química , ADN Ribosómico/genética , Ácidos Grasos/análisis , Halomonadaceae/genética , Halomonadaceae/fisiología , Concentración de Iones de Hidrógeno , Locomoción , Datos de Secuencia Molecular , Hibridación de Ácido Nucleico , Pakistán , Fosfolípidos/análisis , Filogenia , Quinonas/análisis , ARN Ribosómico 16S/genética , Rizosfera , Saccharum/crecimiento & desarrollo , Análisis de Secuencia de ADN , Cloruro de Sodio/metabolismo , Temperatura

RESUMEN

Two Gram-staining-negative, moderately halophilic bacteria, strains M1-18(T) and L1-16, were isolated from a saltern located in Huelva (Spain). They were motile, strictly aerobic rods, growing in the presence of 3-25% (w/v) NaCl (optimal growth at 7.5-10% [w/v] NaCl), between pH 4.0 and 9.0 (optimal at pH 6.0-7.0) and at temperatures between 15 and 40°C (optimal at 37°C). Phylogenetic analysis based on 16S rRNA gene sequence comparison showed that both strains showed the higher similarity values with Chromohalobacter israelensis ATCC 43985(T) (95.2-94.8%) and Chromohalobacter salexigens DSM 3043(T) (95.0-94.9%), and similarity values lower than 94.6% with other species of the genera Chromohalobacter, Kushneria, Cobetia or Halomonas. Multilocus sequence analysis (MLSA) based on the partial sequences of atpA, rpoD and secA housekeeping genes indicated that the new isolates formed an independent and monophyletic branch that was related to the peripheral genera of the family Halomonadaceae, Halotalea, Carnimonas and Zymobacter, supporting their placement as a new genus of the Halomonadaceae. The DNA-DNA hybridization between both strains was 82%, whereas the values between strain M1-18(T) and the most closely related species of Chromohalobacter and Kushneria were equal or lower to 48%. The major cellular fatty acids were C18:1ω7c/C18:1ω6c, C16:0, and C16:1ω7c/C16:1ω6c, a profile that differentiate this new taxon from species of the related genera. We propose the placement of both strains as a novel genus and species, within the family Halomonadaceae, with the name Larsenia salina gen. nov., sp. nov. The type strain is M1-18(T) (=CCM 8464=CECT 8192(T)=IBRC-M 10767(T)=LMG 27461(T)).

Asunto(s)

Microbiología Ambiental , Halomonadaceae/clasificación , Halomonadaceae/genética , Tipificación de Secuencias Multilocus , Aerobiosis , Proteínas Bacterianas/genética , Técnicas de Tipificación Bacteriana , Análisis por Conglomerados , Citosol/química , ADN Bacteriano/química , ADN Bacteriano/genética , ADN Ribosómico/química , ADN Ribosómico/genética , Ácidos Grasos/análisis , Halomonadaceae/aislamiento & purificación , Halomonadaceae/fisiología , Concentración de Iones de Hidrógeno , Locomoción , Datos de Secuencia Molecular , Hibridación de Ácido Nucleico , Filogenia , ARN Ribosómico 16S/genética , Homología de Secuencia de Ácido Nucleico , Cloruro de Sodio/metabolismo , España , Temperatura

RESUMEN

Moss bugs (Coleorrhyncha: Peloridiidae) are members of the order Hemiptera, and like many hemipterans, they have symbiotic associations with intracellular bacteria to fulfill nutritional requirements resulting from their unbalanced diet. The primary endosymbiont of the moss bugs, Candidatus Evansia muelleri, is phylogenetically related to Candidatus Carsonella ruddii and Candidatus Portiera aleyrodidarum, primary endosymbionts of psyllids and whiteflies, respectively. In this work, we report the genome of Candidatus Evansia muelleri Xc1 from Xenophyes cascus, which is the only obligate endosymbiont present in the association. This endosymbiont possesses an extremely reduced genome similar to Carsonella and Portiera. It has crossed the borderline to be considered as an autonomous cell, requiring the support of the insect host for some housekeeping cell functions. Interestingly, in spite of its small genome size, Evansia maintains enriched amino acid (complete or partial pathways for ten essential and six nonessential amino acids) and sulfur metabolisms, probably related to the poor diet of the insect, based on bryophytes, which contains very low levels of nitrogenous and sulfur compounds. Several facts, including the congruence of host (moss bugs, whiteflies, and psyllids) and endosymbiont phylogenies and the retention of the same ribosomal RNA operon during genome reduction in Evansia, Portiera, and Carsonella, suggest the existence of an ancient endosymbiotic Halomonadaceae clade associated with Hemiptera. Three possible scenarios for the origin of these three primary endosymbiont genera are proposed and discussed.

Asunto(s)

Halomonadaceae/genética , Hemípteros/microbiología , Simbiosis , Animales , Evolución Molecular , Reordenamiento Génico , Halomonadaceae/fisiología , Microscopía Electrónica de Transmisión , Filogenia

RESUMEN

The infection density of symbionts is among the major parameters to understand their biological effects in host-endosymbionts interactions. Diaphorina citri harbors two bacteriome-associated bacterial endosymbionts (Candidatus Carsonella ruddii and Candidatus Profftella armatura), besides the intracellular reproductive parasite Wolbachia. In this study, the density dynamics of the three endosymbionts associated with the psyllid D. citri was investigated by real-time quantitative PCR (qPCR) at different developmental stages. Bacterial density was estimated by assessing the copy number of the 16S rRNA gene for Carsonella and Profftella, and of the ftsZ gene for Wolbachia. Analysis revealed a continuous growth of the symbionts during host development. Symbiont growth and rate curves were estimated by the Gompertz equation, which indicated a negative correlation between the degree of symbiont-host specialization and the time to achieve the maximum growth rate (t*). Carsonella densities were significantly lower than those of Profftella at all host developmental stages analyzed, even though they both displayed a similar trend. The growth rates of Wolbachia were similar to those of Carsonella, but Wolbachia was not as abundant. Adult males displayed higher symbiont densities than females. However, females showed a much more pronounced increase in symbiont density as they aged if compared to males, regardless of the incorporation of symbionts into female oocytes and egg laying. The increased density of endosymbionts in aged adults differs from the usual decrease observed during host aging in other insect-symbiont systems.

Asunto(s)

Betaproteobacteria/fisiología , Halomonadaceae/fisiología , Hemípteros/microbiología , Simbiosis , Wolbachia/fisiología , Animales , Betaproteobacteria/genética , Betaproteobacteria/crecimiento & desarrollo , ADN Bacteriano/genética , ADN Bacteriano/metabolismo , Femenino , Halomonadaceae/genética , Halomonadaceae/crecimiento & desarrollo , Hemípteros/crecimiento & desarrollo , Masculino , Ninfa/crecimiento & desarrollo , Ninfa/microbiología , Óvulo/crecimiento & desarrollo , Óvulo/microbiología , Dinámica Poblacional , ARN Ribosómico 16S/genética , ARN Ribosómico 16S/metabolismo , Reacción en Cadena en Tiempo Real de la Polimerasa , Wolbachia/genética , Wolbachia/crecimiento & desarrollo

Asunto(s)

Halomonadaceae/aislamiento & purificación , Halomonadaceae/fisiología , Microbiología del Suelo , Filogenia , ARN Ribosómico 16S , Sodio/análisis , Suelo/química

RESUMEN

Polysaccharides are a promising material for nonfouling surfaces because their chemical composition makes them highly hydrophilic and able to form water-storing hydrogels. Here we investigated the nonfouling properties of hyaluronic acid (HA) and chondroitin sulfate (CS) against marine fouling organisms. Additionally, the free carboxyl groups of HA and CS were postmodified with the hydrophobic trifluoroethylamine (TFEA) to block free carboxyl groups and render the surfaces amphiphilic. All coatings were tested with respect to their protein resistance and against settlement and adhesion of different marine fouling species. Both the settlement and adhesion strength of a marine bacterium (Cobetia marina), zoospores of the seaweed Ulva linza, and cells of a diatom (Navicula incerta) were reduced compared to glass control surfaces. In most cases, TFEA capping increased or maintained the performance of the HA coatings, whereas for the very well performing CS coatings the antifouling performance was reduced after capping.

Asunto(s)

Organismos Acuáticos/química , Incrustaciones Biológicas/prevención & control , Diatomeas/química , Halomonadaceae/química , Ulva/química , Organismos Acuáticos/fisiología , Adhesión Bacteriana/efectos de los fármacos , Adhesión Celular/efectos de los fármacos , Sulfatos de Condroitina/química , Sulfatos de Condroitina/farmacología , Diatomeas/fisiología , Etilaminas/química , Halomonadaceae/fisiología , Ácido Hialurónico/química , Ácido Hialurónico/farmacología , Interacciones Hidrofóbicas e Hidrofílicas , Propiedades de Superficie , Tensoactivos/química , Tensoactivos/farmacología , Ulva/fisiología

RESUMEN

Dynamic change of the surface area and topology of elastomers is used as a general, environmentally friendly approach for effectively detaching micro- and macro-fouling organisms adhered on the elastomer surfaces. Deformation of elastomer surfaces under electrical or pneumatic actuation can debond various biofilms and barnacles. The bio-inspired dynamic surfaces can be fabricated over large areas through simple and practical processes. This new mechanism is complementary with existing materials and methods for biofouling control.

Asunto(s)

Incrustaciones Biológicas , Animales , Biopelículas , Elastómeros/química , Halomonadaceae/fisiología , Propiedades de Superficie , Thoracica/fisiología

RESUMEN

"Candidatus Portiera aleyrodidarum" is the primary endosymbiont of whiteflies. We report two complete genome sequences of this bacterium from the worldwide invasive B and Q biotypes of the whitefly Bemisia tabaci. Differences in the two genome sequences may add insights into the complex differences in the biology of both biotypes.

Asunto(s)

Halomonadaceae/aislamiento & purificación , Halomonadaceae/fisiología , Hemípteros/microbiología , Simbiosis , Animales , ADN Bacteriano/química , ADN Bacteriano/genética , Genoma Bacteriano , Halomonadaceae/clasificación , Halomonadaceae/genética , Datos de Secuencia Molecular

RESUMEN

The taxonomic status of a moderately halophilic bacterium, strain N4(T), isolated from soil of a chicken farm in China was determined. It was Gram-negative, non-spore-forming, motile, and rod-shaped. Phylogenetic analysis based on 16S rRNA gene sequence indicated that this strain belonged to the genus Salinicola, as it showed the highest sequence similarities to Salinicola salaries M27(T) (98.3 %), Salinicola socius SMB35(T) (98.1 %), and Salinicola halophilus CG4.1(T) (98.1 %). The major cellular fatty acids were C(16:0) (25.6 %), C(18:1)ω7c (35.0 %), and C(19:0) cyclo ω8c (11.9 %), which are properties shared by members of the genus Salinicola. The DNA G+C content of strain N4(T) was 69.1 mol %. The level of DNA-DNA relatedness between strain N4(T) and the other three type strains of the genus of Salinicola salaries M27(T), Salinicola socius SMB35(T), and Salinicola halophilus CG4.1(T) were 34.3, 28.7, and 26.9 %, respectively. Based on the results of phenotypic, chemotaxonomic, DNA-DNA relatedness, and phylogenetic analysis, strain N4(T) should be classified as a novel species of the genus Salinicola, for which the name Salinicola zeshunii sp. nov. is proposed, with strain N4(T) (=KACC 16602(T) = CCTCC AB 2012912(T)) as the type strain.

Asunto(s)

Halomonadaceae/clasificación , Halomonadaceae/aislamiento & purificación , Microbiología del Suelo , Animales , Técnicas de Tipificación Bacteriana , Composición de Base , Pollos , China , Análisis por Conglomerados , ADN Bacteriano/química , ADN Bacteriano/genética , ADN Ribosómico/química , ADN Ribosómico/genética , Ácidos Grasos/análisis , Halomonadaceae/genética , Halomonadaceae/fisiología , Microscopía Electrónica de Transmisión , Datos de Secuencia Molecular , Hibridación de Ácido Nucleico , Filogenia , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN

RESUMEN

The genome of "Candidatus Portiera aleyrodidarum," the primary endosymbiont of the whitefly Bemisia tabaci (Mediterranean species), is reported. It presents a reduced genome (357 kb) encoding the capability to synthetize, or participate in the synthesis of, several amino acids and carotenoids, being the first insect endosymbiont capable of supplying carotenoids.

Asunto(s)

ADN Bacteriano/química , ADN Bacteriano/genética , Genoma Bacteriano , Halomonadaceae/genética , Análisis de Secuencia de ADN , Aminoácidos/metabolismo , Animales , Carotenoides/metabolismo , Halomonadaceae/aislamiento & purificación , Halomonadaceae/metabolismo , Halomonadaceae/fisiología , Hemípteros/microbiología , Hemípteros/fisiología , Datos de Secuencia Molecular , Simbiosis

RESUMEN

"Candidatus Portiera aleyrodidarum" is the obligate primary endosymbiotic bacterium of whiteflies, including the sweet potato whitefly Bemisia tabaci, and provides essential nutrients to its host. Here we report two complete genome sequences of this bacterium from the B and Q biotypes of B. tabaci.

Asunto(s)

ADN Bacteriano/química , ADN Bacteriano/genética , Genoma Bacteriano , Halomonadaceae/genética , Análisis de Secuencia de ADN , Animales , Halomonadaceae/aislamiento & purificación , Halomonadaceae/fisiología , Hemípteros/clasificación , Hemípteros/microbiología , Hemípteros/fisiología , Datos de Secuencia Molecular , Simbiosis

RESUMEN

The fouling resistance of oligo(ethylene glycol) (OEG)-terminated self-assembled monolayers (SAMs) of alkanethiolates on gold has been well established. Although hydration of the OEG chains seems key to OEG-SAM resistance to macromolecular adsorption and cellular attachment, the details of how hydration prevents biofouling have been inferred largely through computational methods. Because OEG-SAMs of different lengths exhibit differing degrees of fouling resistance, the interactions between water and OEG-SAMs leading to fouling resistance can be deduced by comparing the properties of fouling and nonfouling OEG-SAMs. While all OEG-SAMs had similar water contact angles, contact angles taken with glycerol were able to individuate between different OEG-SAMs and between fouling and nonfouling OEG-SAMs. Subsequent estimation of surface and interfacial tension using a colloidal model showed that nonfouling surfaces are associated with an increased negative interfacial tension between those OEG-SAMs that resisted attachment and water. Further analysis of this interfacial tension experimentally confirmed current mathematical models that cite OEG-water hydrogen-bond formation as a driving force behind short-term fouling resistance. Finally, we found a correlation between solid-water interfacial tension and packing density and molecular density of ethylene glycol.

Asunto(s)

Adhesión Bacteriana , Polietilenglicoles/química , Alcanos/química , Adhesión Bacteriana/efectos de los fármacos , Incrustaciones Biológicas/prevención & control , Coloides , Oro/química , Halomonadaceae/efectos de los fármacos , Halomonadaceae/fisiología , Polietilenglicoles/farmacología , Tensión Superficial , Termodinámica , Agua/química

RESUMEN

A novel bioflocculant-producing bacteria was isolated from sediment samples of Algoa Bay in the Eastern Cape Province of South Africa and the effect of culture conditions on the bioflocculant production was investigated. Analysis of the partial nucleotide sequence of the 16S rDNA of the bacteria revealed 99% similarity to Cobetia sp. L222 and the sequence was deposited in GenBank as Cobetia sp. OAUIFE (accession number JF799092). Cultivation condition studies revealed that bioflocculant production was optimal with an inoculum size of 2% (v/v), initial pH of 6.0, Mn(2+) as the metal ion, and glucose as the carbon source. Metal ions, including Na(+), K(+), Li(+), Ca(2+)and Mg(2+) stimulated bioflocculant production, resulting in flocculating activity of above 90%. This crude bioflocculant is thermally stable, with about 78% of its flocculating activity remaining after heating at 100 °C for 25 min. Analysis of the purified bioflocculant revealed it to be an acidic extracellular polysaccharide.

Asunto(s)

Floculación , Halomonadaceae/fisiología , Sedimentos Geológicos/microbiología , Calor , Datos de Secuencia Molecular , Sudáfrica

RESUMEN

For both, environmental and medical applications, the quantification of bacterial adhesion is of major importance to understand and support the development of new materials. For marine applications, the demand is driven by the quest for improved fouling-release coatings. To determine the attachment strength of bacteria to coatings, a microfluidic adhesion assay has been developed which allows probing at which critical wall shear stress bacteria are removed from the surface. Besides the experimental setup and the optimization of the assay, we measured adhesion of the marine bacterium Cobetia marina on a series of differently terminated self-assembled monolayers. The results showed that the adhesion strength of C. marina changes with surface chemistry. The difference in critical shear stress needed to remove bacteria can vary by more than one order of magnitude if a hydrophobic material is compared to an inert chemistry such as polyethylene glycol.

Asunto(s)

Adhesión Bacteriana , Técnicas Bacteriológicas/métodos , Microbiología Ambiental , Halomonadaceae/fisiología , Microfluídica/métodos , Propiedades de Superficie