Una nueva especie de atelopus (amphibia: anura: bufonidae) del páramo de tama, estado apure, venezuela

Se describe una especie nueva de rana, Atelopus tamaense, del páramo el Tama, en el Estado Apure, Venezuela. El taxon se distingue de todos los demás miembros del género por la combinación de extensivo ''webbing" y coloración distintiva. Se suministran datos sobre su morfología externa, piel, coloración, variación intraespecífica, dimorfismo sexual y ecología. Se incluye una clave para la identificación de las especies venezolanas de Atelopus y se hacen algunas comparaciones para diferenciar la especie nueva de las especies de Atelopus colombianas y venezolanas del grupo de A. ignescens al cual pertenece A. tamaense.A new species of frog, Atelopus tamaense, is described from Páramo El Tamá, Estado Apure, Venezuela. The taxon is distinguished from all other members of the genus by the combination of extensive webbing and distinctive coloration. Data are provided for external morphology, skin, coloration, intraspecific variation, sexual dimorphism, and ecology. A key is included to identify Venezuelan Atelopus and some comparisons are given to distinguish the new species from Colombian and Venezuelan species of Atelopus of the A. ignescens group, to which A. tamaense belongs

Increase of Transmitted Drug Resistance among HIV-Infected Sub-Saharan Africans Residing in Spain in Contrast to the Native Population

BACKGROUND: The prevalence of transmitted HIV drug resistance (TDR) is stabilizing or decreasing in developed countries. However, this trend is not specifically evaluated among immigrants from regions without well-implemented antiretroviral strategies. METHODS: TDR trends during 1996-2010 were analyzed among naïve HIV-infected patients in Spain, considering their origin and other factors. TDR mutations were defined according to the World Health Organization list. RESULTS: Pol sequence was available for 732 HIV-infected patients: 292 native Spanish, 226 sub-Saharan Africans (SSA), 114 Central-South Americans (CSA) and 100 from other regions. Global TDR prevalence was 9.7% (10.6% for Spanish, 8.4% for SSA and 7.9% for CSA). The highest prevalences were found for protease inhibitors (PI) in Spanish (3.1%), for non-nucleoside reverse transcriptase inhibitors (NNRTI) in SSA (6.5%) and for nucleoside reverse transcriptase inhibitors (NRTI) in both Spanish and SSA (6.5%). The global TDR rate decreased from 11.3% in 2004-2006 to 8.4% in 2007-2010. Characteristics related to a decreasing TDR trend in 2007-10 were Spanish and CSA origin, NRTI- and NNRTI-resistance, HIV-1 subtype B, male sex and infection through injection drug use. TDR remained stable for PI-resistance, in patients infected through sexual intercourse and in those carrying non-B variants. However, TDR increased among SSA and females. K103N was the predominant mutation in all groups and periods. CONCLUSION: TDR prevalence tended to decrease among HIV-infected native Spanish and Central-South Americans, but it increased up to 13% in sub-Saharan immigrants in 2007-2010. These results highlight the importance of a specific TDR surveillance among immigrants to prevent future therapeutic failures, especially when administering NNRTIs

Soybean lectin enhances biofilm formation by Bradyrhizobium japonicum in the absence of plants

Soybean lectin (SBL) purified fromsoybean seeds by affinity chromatography strongly bound to Bradyrhizobium japonicum USDA 110 cell surface. This lectin enhanced biofilm formation by B. japonicum in a concentration-dependent manner. Presence of galactose during biofilm formation had different effects in the presence or absence of SBL. Biofilms were completely inhibited in the presence of both SBL and galactose, while in the absence of SBL, galactose was less inhibitory. SBL was very stable, since its agglutinating activity of B. japonicum cells as well as of human group A+ erythrocytes was resistant to preincubation for one week at 60°C. Hence, we propose that plant remnants might constitute a source of this lectin, which might remain active in soil and thus favor B. japonicum biofilm formation in the interval between soybean crop seasons.Facultad de Ciencias ExactasInstituto de Biotecnologia y Biologia Molecula

Strain selection for improvement of Bradyrhizobium japonicum competitiveness for nodulation of soybean

A Bradyrhizobium japonicum USDA 110-derived strain able to produce wider halos in soft-agar medium than its parental strain was obtained by recurrent selection. It was more chemotactic than the wild type towards mannitol and three amino acids. When cultured in minimal medium with mannitol as a single carbon-source, it had one thick subpolar flagellum as the wild type, plus several other flagella that were thinner and sinusoidal. Root adsorption and infectivity in liquid media were 50-100% higher for the selected strain, but root colonization in water-unsaturated vermiculite was similar to the wild type. A field experiment was then carried out in a soil with a naturalized population of 1.8 × 105 soybean-nodulating rhizobia g of soil -1. Bradyrhizobium japonicum strains were inoculated either on the soybean seeds or in the sowing furrows. Nodule occupation was doubled when the strains were inoculated in the sowing furrows with respect to seed inoculation (significant with P<0.05). On comparing strains, nodule occupation with seed inoculation was 6% or 10% for the wild type or selected strains, respectively, without a statistically significant difference, while when inoculated in the sowing furrows, nodule occupation increased to 12% and 22%, respectively (differences significant with P<0.05).Instituto de Biotecnologia y Biologia Molecula

Strain selection for improvement of Bradyrhizobium japonicum competitiveness for nodulation of soybean

A Bradyrhizobium japonicum USDA 110-derived strain able to produce wider halos in soft-agar medium than its parental strain was obtained by recurrent selection. It was more chemotactic than the wild type towards mannitol and three amino acids. When cultured in minimal medium with mannitol as a single carbon-source, it had one thick subpolar flagellum as the wild type, plus several other flagella that were thinner and sinusoidal. Root adsorption and infectivity in liquid media were 50-100% higher for the selected strain, but root colonization in water-unsaturated vermiculite was similar to the wild type. A field experiment was then carried out in a soil with a naturalized population of 1.8 × 105 soybean-nodulating rhizobia g of soil -1. Bradyrhizobium japonicum strains were inoculated either on the soybean seeds or in the sowing furrows. Nodule occupation was doubled when the strains were inoculated in the sowing furrows with respect to seed inoculation (significant with P<0.05). On comparing strains, nodule occupation with seed inoculation was 6% or 10% for the wild type or selected strains, respectively, without a statistically significant difference, while when inoculated in the sowing furrows, nodule occupation increased to 12% and 22%, respectively (differences significant with P<0.05).Instituto de Biotecnologia y Biologia Molecula

Analysis of the role of the two flagella of Bradyrhizobium japonicum in competition for nodulation of soybean

Bradyrhizobium japonicum has two types of flagella. One has thin filaments consisting of the 33-kDa flagellins FliCI and FliCII (FliCI-II) and the other has thick filaments consisting of the 65-kDa flagellins FliC1, FliC2, FliC3, and FliC4 (FliC1-4). To investigate the roles of each flagellum in competition for nodulation, we obtained mutants deleted in fliCI-II and/or fliC1-4 in the genomic backgrounds of two derivatives from the reference strain USDA 110: the streptomycin-resistant derivative LP 3004 and its more motile derivative LP 3008. All mutations diminished swimming motility. When each mutant was co-inoculated with the parental strain on soybean plants cultivated in vermiculite either at field capacity or flooded, their competitiveness differed according to the flagellin altered. ΔfliCI-II mutants were more competitive, occupying 64-80% of the nodules, while ΔfliC1-4 mutants occupied 45-49% of the nodules. Occupation by the nonmotile double mutant decreased from 55% to 11% as the water content of the vermiculite increased from 85% to 95% field capacity to flooding. These results indicate that the influence of motility on competitiveness depended on the water status of the rooting substrate.Instituto de Biotecnologia y Biologia Molecula

Analysis of the role of the two flagella of Bradyrhizobium japonicum in competition for nodulation of soybean

Bradyrhizobium japonicum has two types of flagella. One has thin filaments consisting of the 33-kDa flagellins FliCI and FliCII (FliCI-II) and the other has thick filaments consisting of the 65-kDa flagellins FliC1, FliC2, FliC3, and FliC4 (FliC1-4). To investigate the roles of each flagellum in competition for nodulation, we obtained mutants deleted in fliCI-II and/or fliC1-4 in the genomic backgrounds of two derivatives from the reference strain USDA 110: the streptomycin-resistant derivative LP 3004 and its more motile derivative LP 3008. All mutations diminished swimming motility. When each mutant was co-inoculated with the parental strain on soybean plants cultivated in vermiculite either at field capacity or flooded, their competitiveness differed according to the flagellin altered. ΔfliCI-II mutants were more competitive, occupying 64-80% of the nodules, while ΔfliC1-4 mutants occupied 45-49% of the nodules. Occupation by the nonmotile double mutant decreased from 55% to 11% as the water content of the vermiculite increased from 85% to 95% field capacity to flooding. These results indicate that the influence of motility on competitiveness depended on the water status of the rooting substrate.Instituto de Biotecnologia y Biologia Molecula

Lack of Galactose or Galacturonic Acid in <i>Bradyrhizobium japonicum</i> USDA 110 Exopolysaccharide Leads to Different Symbiotic Responses in Soybean

Exopolysaccharide (EPS) and lipopolysaccharide (LPS) from Bradyrhizobium japonicum are important for infection and nodulation of soybean (Glycine max), although their roles are not completely understood. To better understand this, we constructed mutants in B. japonicum USDA 110 impaired in galactose or galacturonic acid incorporation into the EPS without affecting the LPS. The derivative LP 3010 had a deletion of lspL-ugdH and produced EPS without galacturonic acid whereas LP 3013, with an insertion in exoB, produced EPS without galactose. In addition, the strain LP 3017, with both mutations, had EPS devoid of both galactosides. The missing galactosides were not replaced by other sugars. The defects in EPS had different consequences. LP 3010 formed biofilms and nodulated but was defective in competitiveness for nodulation; and, inside nodules, the peribacteroid membranes tended to fuse, leading to the merging of symbiosomes. Meanwhile, LP 3013 and LP 3017 were unable to form biofilms and produced empty pseudonodules but exoB suppressor mutants were obtained when LP 3013 plant inoculation was supplemented with wild-type EPS. Similar phenotypes were observed with all these mutants in G. soja. Therefore, the lack of each galactoside in the EPS has a different functional effect on the B. japonicum-soybean symbiosis.Facultad de Ciencias ExactasInstituto de Biotecnologia y Biologia Molecula

Genotypic tropism testing in proviral DNA to guide maraviroc initiation in aviremic subjects: 48-week analysis of the PROTEST study

Introduction: In a previous interim 24-week virological safety analysis of the PROTEST study (1), initiation of Maraviroc (MVC) plus 2 nucleoside reverse-transcriptase inhibitors (NRTIs) in aviremic subjects based on genotypic tropism testing of proviral HIV-1 DNA was associated with low rates of virological failure. Here we present the final 48-week analysis of the study. Methods: PROTEST was a phase 4, prospective, single-arm clinical trial (ID: NCT01378910) carried on in 24 HIV care centres in Spain. Maraviroc-naïve HIV-1-positive adults with HIV-1 RNA (VL) 10% in a singleton), initiated MVC with 2 NRTIs and were followed for 48 weeks. Virological failure was defined as two consecutive VL>50 c/mL. Recent adherence was calculated as: (# pills taken/# pills prescribed during the previous week)*100. Results: Tropism results were available from 141/175 (80.6%) subjects screened: 87/141 (60%) were R5 and 74/87 (85%) were finally included in the study. Their median age was 48 years, 16% were women, 31% were MSM, 36% had CDC category C at study entry, 62% were HCV+ and 10% were HBV+. Median CD4+ counts were 616 cells/mm(3) at screening, and median nadir CD4+ counts were 143 cells/mm(3). Previous ART included PIs in 46 (62%) subjects, NNRTIs in 27 (36%) and integrase inhibitors (INIs) in 1 (2%). The main reasons for treatment change were dyslipidemia (42%), gastrointestinal symptoms (22%), and liver toxicity (15%). MVC was given alongside TDF/FTC in 40 (54%) subjects, ABC/3TC in 30 (40%), AZT/3TC in 2 (3%) and ABC/TDF in 2 (3%). Sixty-two (84%) subjects maintained VL<50 c/mL through week 48, whereas 12 (16%) discontinued treatment: two (3%) withdrew informed consent, one (1%) had a R5→X4 shift in HIV tropism between the screening and baseline visits, one (1%) was lost to follow-up, one (1%) developed an ART-related adverse event (rash), two (3%) died due to non-study-related causes (1 myocardial infarction at week 0 and 1 lung cancer at week 36), and five (7%) developed protocol-defined virological failure, although two of them regained VL<50 c/mL with the same MVC regimen (Table 1). Conclusions: Initiation of MVC plus 2 NRTIs in aviremic subjects based on genotypic tropism testing of proviral HIV-1 DNA is associated with low rates of virological failure up to one year