Is vertical transmission the only pathway for Rickettsia felis?

The genus Rickettsia encompasses several species grouped into two main clusters, Typhus and the Transitional groups. The latter group contains Rickettsia felis, an endosymbiont of several arthropods with an uncertain human pathogenicity and whose most efficient transmission mechanism described thus far is transovarial. The aim of this study was to evaluate whether this pathway exists using phylogenetic analysis and partial sequences of the 17kDa and gltA genes and comparing them with host phylogeny using the cytb region. This is the first study that evaluates the vertical transmission of R. felis. In general, both phylogenies of R. felis showed no polytomies, as suspected if this pathway was the only pathway occurring. When phylogenies of the invertebrates and the gltA of R. felis were compared for strong coevolutionary insight, intricate relationships were observed, suggesting that other transmission pathways must occur, such as horizontal transmission. Further studies are needed to determine which other transmission routes occur in hematophagous arthropods.

Physiological stabilization, community characterization, and nitrogen degradation dynamics in an anammox consortium from estuarine sediments.

Anammox is a cost-effective and sustainable process for nitrogen removal; however, the production of a physiologically stable inoculum is a critical point in the start-up process. In this work, estuarine sediments were used as incubation seeds to obtain cultures with stable anammox activity. Assays were performed in batch cultures fed with stoichiometric amounts of ammonium and nitrite, analyzing physiological response variables and the microbial community. Estuarine sediments showed a stable anammox process after 90 days, consuming ammonium and nitrite simultaneously with concomitant generation of N2 and nitrate in stoichiometric amounts. In kinetic assays, substrates were fully consumed after 210 hr, exhibiting N2 and nitrate yields of 0.85 and 0.10, respectively. The microbial community analysis using PCR-DGGE indicated the presence of uncultured anammox bacteria and members of the genus Candidatus Jettenia. The results evidenced the achievement of anammox cultures, although their start-up and kinetic characteristics were less favorable than those recorded in man-made systems. PRACTITIONER POINTS: Estuarine sediments were used as incubation seeds to obtain cultures with stable anammox activity. The sediments were fed with stoichiometric amounts of ammonium and nitrite, analyzing the physiological response variables and the microbial community. Sediments showed a stable anammox process after 90 days, converting the substrates into N2 and nitrate according to stoichiometry. Anammox cultures were achieved although their start-up and kinetic characteristics were less favorable than those recorded in man-made systems. Microbial community analysis using PCR-DGGE indicated the presence of uncultured anaerobic ammonia-oxidizing bacterium and members of genus Candidatus Jettenia.

Pontoscolex corethrurus: A homeless invasive tropical earthworm?

The presence of earthworm species in crop fields is as old as agriculture itself. The earthworms Pontoscolex corethrurus (invasive) and Balanteodrilus pearsei (native) are associated with the emergence of agriculture and sedentism in the region Amazon and Maya, respectively. Both species have shifted their preference from their natural habitat to the cropland niche. They contrast in terms of intensification of agricultural land use (anthropic impact to the symbiotic soil microbiome). P. corethrurus inhabits conventional agroecosystems, while B. pearsei thrives in traditional agroecosystems, i.e., P. corethrurus has not yet been recorded in soils where B. pearsei dwells. The demographic behavior of these two earthworm species was assessed in the laboratory over 100 days, according to their origin (OE; P. corethrurus and B. pearsei) food quality (FQ; soil only, maize stubble, Mucuna pruriens), and soil moisture (SM; 25, 33, 42%). The results showed that OE, FQ, SM, and the OE x FQ interaction were highly significant for the survival, growth, and reproduction of earthworms. P. corethrurus showed a lower survival rate (> mortality). P. corethrurus survivors fed a diet of low-to-intermediate nutritional quality (soil and stubble maize, respectively) showed a greater capacity to grow and reproduce; however, it was surpassed by the native earthworm when fed a high-quality diet (M. pruriens). Besides, P. corethrurus displayed a low cocoon hatching (emergence of juveniles). These results suggest that the presence of the invasive species was associated with a negative interaction with the soil microbiota where the native species dwells, and with the absence of natural mutualistic bacteria (gut, nephridia, and cocoons). These results are consistent with the absence of P. corethrurus in milpa and pasture-type agricultural niches managed by peasants (agroecologists) to grow food regularly through biological soil management. Results reported here suggest that P. corethrurus is an invasive species that is neither wild nor domesticated, that is, its eco-evolutionary phylogeny needs to be derived based on its symbionts.

Agrobacterium tumefaciens-mediated transformation of common bean (Phaseolus vulgaris) var. Brunca

Common bean is a crop recalcitrant to in vitro regeneration and therefore it lacks an efficient transformation protocol that can be reproduced using A. tumefaciens. The main goal of this study was to establish a protocol for A. tumefaciens mediated transformation of Phaseolus vulgaris var. Brunca by marker genes (gusA and nptII) together with the gene for trehalose-6-phosphate synthase from Saccharomyces cerevisiae (TPS1) used in other species to increase tolerance to abiotic stress. The β-glucuronidase activity was detected in 45 % of the LBA4404 ElectroMAX® pCAMBIA1301 infected explants. Transformed explants regenerated new shoots after four to five months period in a kanamycin rich media. Surviving plants were evaluated by PCR and presented an 0.5 % efficiency of transformation. The established protocol for genetic transformation of common bean has two additional advantages with respect to previous reports: (1) it allows for obtaining transformed regenerants and (2) the genetic transformation was stable for the selective gene.

El frijol común en un cultivo recalcitrante a la regeneración in vitro y se carece de un protocolo eficiente y reproducible de transformación genética usando A. tumefaciens. Desarrollamos un protocolo de transformación genética mediada por A. tumefaciens de frijol común variedad Brunca utilizando genes marcadores (gusA y nptII) junto con el gen de la trehalosa-6-fosfato sintasa de levadura (TPS1) utilizado para incrementar tolerancia a estrés abiótico. La actividad de la β-glucoronidasa fue detectada en 45 % de los explantes infectados con la cepa LBA4404 de A. tumefaciens transformada con pCAMBIA1301. Después de 4 o 5 meses se regeneraron tallos en un medio adicionado con kanamicina. Los explantes supervivientes se evaluaron mediante PCR y presentaron una eficiencia de transformación de 0.5 %. El protocolo de transformación genética de frijol común establecido tiene dos ventajas adicionales con respecto a los reportes previos: (1) permite la obtención de regenerares transformados y (2) la transformación genética fue estable para el gen selectivo.

Expression analysis of two SOMATIC EMBRYOGENESIS RECEPTOR KINASE (SERK) genes during in vitro morphogenesis in Spanish cedar (Cedrela odorata L.).

Somatic embryogenesis (SE) is one of the most important steps during regeneration, but the molecular mechanism of SE remains unclear for Cedrela odorata. SOMATIC EMBRYOGENESIS RECEPTOR-LIKE KINASE (SERK) is one of the genes associated with induction of SE and is considered a marker of cells competent to form somatic embryos. Our objective was to clone and characterize the SERK1 and SERK2 gene homologues and analyze their expression patterns during in vitro morphogenesis in Spanish cedar. CoSERK1 and CoSERK2 were isolated from cedar, both share domains characteristic of the SERK family, including leucine-rich repeats, a proline-rich motif, a transmembrane domain, and kinase domains. Embryogenic cultures were established from callus cultures induced on medium supplemented with 1 mg/L dicamba. Histological sections were studied to determine the embryogenic nature of the samples. The CoSERK1 gene was highly expressed during the acquisition of embryogenic competence. The expression level of SERK1 was lower in non-embryogenic tissues and organs than in embryogenic calli, and it was higher in 3-week old embryogenic calli. CoSERK2 gene was highly expressed in leaves and shoots but no difference in expression was obtained between somatic and embryogenic tissues. These results suggest that the expression of CoSERK1 is associated with somatic embryogenesis induction and could be used as a potential marker to monitor the transition from competent to embryogenic cells and tissues in Spanish cedar.

Micorriza arbuscular, Mucoromycotina y hongos septados oscuros en helechos y licófitas con distribución en México: una revisión global / Arbuscular mycorrhizal, Mucoromycotina and dark septate fungi in ferns and lycophytes with distribution in Mexico: a global review

ResumenLos helechos y licófitas son un grupo de plantas vasculares de interés para entender la evolución de las interacciones micorrízicas y su preservación es de relevancia por sus múltiples interacciones ecológicas. El registro de los diferentes grupos taxonómicos de hongos asociados a helechos y licófitas se encuentra fragmentado y el criterio para su diagnóstico inconsistente, lo que dificulta el entendimiento y la determinación del estatus micorrízico. El objetivo del presente trabajo fue conocer el porcentaje de especies de helechos y licófitas que tiene distribución en México de las que se tiene información sobre hongos endomicorrízicos. Se integró un listado de la presencia de hongos micorrízicos arbusculares (HMA), Mucoromycotina y hongos septados oscuros (HSO) asociados a helechos y licófitas, a través de una búsqueda exhaustiva de información. En este trabajo se consideró una especie micorrízica arbuscular, por los arbúsculos, para diferenciarla de la colonización por hifas, vesículas u ovillos. El estudio generó un listado de ocurrencia de interacciones endomicorrízicas en 27 familias, 61 géneros y 137 especies de helechos y licófitas, que representa el 13.37 % de las especies, 91 % de los géneros y 77 % de las familias registradas para México. El 78.1 % de las especies presentó colonización por hongos, el 56.2 % fueron por HMA, el 8.9 % solo presentó colonización por hifas, vesículas o coils, el 21.8 % fue por HSO y el 1. 4 % por hongos Mucoromycotina. Del total de especies, la mayor presencia de colonización se presentó en especies terrestres 76.59 %, saxícolas 33.33 %, acuáticas 20 % y epífitas con 6.25 %. Las familias de helechos y licófitas con mayor número de especies colonizadas fueron: Pteridaceae, Polypodiaceae, Aspleniaceae y Dryopteridaceae. El presente trabajo muestra que la asociación de HMA y HSO es la más ampliamente distribuida en las familias y especies de helechos y licófitas. Surge la necesidad de incluir a los helechos y licófitas en los estudios de interacciones endomicorrízicas ya que únicamente 28 especies (20 %) fueron estudiadas en ecosistemas de México. La mayoría de los estudios se enfocan en la fase esporofítica (80 %). Sin embargo, para entender el papel que juegan las micorrizas en el establecimiento de helechos y licófitas se requiere incluir a la fase gametofítica, así como estudios de ecología, biología molecular, así como trabajos experimentales de fisiología. La información presentada es de relevancia para implementar estrategias alternativas de conservación, debido a que muchas especies de helechos y licófitas requieren de la asociación micorrízica para su crecimiento y supervivencia.

AbstractFerns and lycophytes are a group of vascular plants of interest to understand the evolution of mycorrhizal interactions; their preservation is of relevance for their multiple ecological relations. The record of different taxonomic groups of fungi associated with ferns and lycophytes is fragmentary, and the criteria for it identification is inconsistent, which hinders the understanding and determination of mycorrhizal status. The aim of this study was to determine the percentage of the species of ferns and lycophytes with distribution in Mexico, and with information of fungal interactions. A checklist of the presence of arbuscular mycorrhizal fungi (AMF), Mucoromycotina and dark septate fungi (DSF) associated with ferns and lycophytes was integrated through an exhaustive global literature search. In this study, mycorrhizal species was considered by the presence of arbuscules to differentiate with hyphal, vesicular and coils colonization. The study gathered a checklist of mycorrhizal occurrences of 27 families, 61 genus and 137 species of ferns and lycophytes, which covers 13.4 % of the species, 91 % of the genus and 77 % of the families distributed in Mexico. The 78.1 % of the species showed colonization, 56.2 % by AMF, 29.9 % by DSF and 0.72 % by Mucoromycotina fungi. From the total of the species, the higher presences of colonization were in terrestrial, epiphytic, saxicolous, and aquatic plants with 76.6 %, 33.3 %, 20 %, and 6.3 %, respectively. The families of ferns and lycophytes with the higher number of species colonized were Pteridaceae, Polypodiaceae, Aspleniaceae and Dryopteridaceae. The present study showed the widespread associations of AMF and DSF in ferns and lycophytes of Mexico. It is urgently needed to include ferns and lycophytes in studies focused on endomycorhizal interactions, since only 28 species (28 %) were studied in Mexican ecosystems. The majority of studies were focused on sporophytic face (80 %). Nonetheless, to understand the role that plays the mycorrhiza in the establishment of ferns and lycophytes, it is necessary to include the gametophytic face in ecological, molecular and physiological experimental studies. This information is important to implement conservation strategies, because a considerable number of ferns and lycophytes species, depend on these mycorrhizal associations for their growth and survival. Rev. Biol. Trop. 65 (3): 1062-1081. Epub 2017 September 01.

Colonización y estructura de la comunidad de hongos micorrízicos arbusculares en Alsophila firma (Cyatheaceae) en bosque mesófilo de montaña en Veracruz, México / Colonization and structure of arbuscular mycorrhizal fungi community in Alsophila firma (Cyatheales: Cyatheaceae) from a tropical montane cloud forest in Veracruz, México

Alsophila firma is a tree fern that is distributed mainly in tropical montane cloud forest (TMCF) and is considered as a threatened species. Arbuscular mycorrrhizal fungi (AMF) have been proposed as an alternative in rescue programs of endangered species. However, our knowledge about diversity of AMF and mycorrhizal status of the species of TMCF is limited. In Mexico TMCF shows different degrees of conservation because of fragmentation and land use change. In this study, we evaluated the level of colonization, richness and abundances of spores of AMF in three fragments with different conservation status: conserved (100 years), secondary vegetation (17 years) and disturbed. For this, soil samples and roots were collected from five individuals of A. firma per site, with at least 100m away from each other; a total of 100cm of roots were analysed per site. Root samples showed AMF and occasionally dark septate fungi (DSF) colonizations. For the overall study, 19 species of AMF were recorded: Gigaspora (7), Acaulospora (4), Glomus (4), Funneliformis (2), Sclerocystis (1) and Scutellospora (1). The dominant species in the three sites were Funneliformis geosporum and Acaulospora scrobiculata. The highest diversity (H’) and evenness (J’) (p<0.05) were found in the conserved site (H’=1.7, J’=0.66), when compared to the secondary vegetation (H’=1.5, J’=0.61), and the disturbed site (H’=0.74, J’=0.41). Statistical analysis showed that the AMF degree of colonization was significantly higher (p<0.05) in the conserved site; although, the disturbed site showed low richness and abundances of AMF, the degree of root colonization did not differ statistically (p<0.05) with the secondary vegetation site. Chao2 (Richness estimation model) showed that the number of analysed samples were sufficient to represent the structure of the AMF communities with values >90%. The present study confirmed that A. firma is a mycorrhizal species that exhibits high levels of colonization even in disturbed sites. We suggest that F. geosporum and A. scrobiculata may have the potential to inoculate the gametophyte and young sporophyte of A. firma, to support restoration programs, because of their abundances and high tolerance to disturbed sites.

Alsophila firma es un helecho arborescente que crece principalmente en bosque mesófilo de montaña (BMM) y se encuentra en la categoría de riesgo. Los hongos mico- rrízicos arbusculares (HMA) se han propuesto como una alternativa para programas de recuperación de especies nativas en peligro. Sin embargo, sabemos poco sobre la diversidad de HMA y del estatus micorrízico de las espe- cies vegetales del BMM. En México el BMM presenta diferentes grados de conservación debido a la fragmentación y el cambio de uso de suelo. Se evaluó el grado de colonización, riqueza y abundancia de esporas de los HMA presentes en fragmentos de BMM con diferente historia de manejo: conservado (100 años), en recuperación (17 años) y alterado. Se estudiaron muestras de suelo y raíces toma- das de 5 individuos de A. firma por cada sitio, con al menos 100m de distancia entre individuos. Se analizaron en total 100cm de raíz por cada sitio. Las muestras de raíz presentaron colonización principalmente de HMA y ocasionalmente por hongos septados oscuros (HSO). Se encontraron 19 especies: Gigaspora (7), Acaulospora (4), Glomus (4), Funneliformis (2), Sclerocystis (1) y Scutellospora (1). Las especies dominantes en los tres sitios fueron Funneliformis geosporum y Acaulospora scrobiculata. La mayor diversidad (H’) y equitatividad (J’) (p<0.05) se presentaron en el sitio conservado (H’=1.7; J’ 0.66) con respecto al sitio en recuperación (H’=1.5, J’ 0.61) y alterado (H’=0.74, J’=0.41). Los niveles de colonización micorrízica total de raíz fueron estadísticamente mayores (p<0.05) en el sitio conservado. Aunque el sitio alterado presenta una baja riqueza y abundancia de HMA la colonización micorrízica total de raíz no fue estadísticamente diferente (p<0.05) respecto al sitio en recuperación. El estimador Chao2 indica que las muestras analizadas reflejan la estructura general de la comunidad de HMA con valores superiores al 93%. El presente estudio confirma que A. firma es una especie micorrízica con altos niveles de colonización incluso en sitios alterados. Se sugiere que las especies F. geosporum y A. scrobiculata por su alta tolerancia a sitios alterados pueden tener potencial para inocular gametofitos y esporofitos de A. firma para incrementar la supervivencia en programas de restauración.

Endogenous GUS-like activity in Capsicum chinense Jacq

The gene uidA, codes for beta-glucuronidase, which is one of the reporters more frequently utilized in transgenic plants. However, this can only be use if the selected organism does not present endogenous GUS-like activity. In tissues of C. chinense we found a GUS-like activity showing different levels of intensity. Histochemical screening showed that endogenous GUS-like activity decreased, or reduced significantly, in almost all tissues with exception of stament, when phosphate buffer was adjusted to pH 8. Subsequently, C. chinense zygotic embryo explants were transient transformed with Agrobacterium tumefaciens LBA4404 (pCAMBIA2301) and plantlets regenerated were histochemically stained in phosphate buffer pH 8. Observations of incubated tissues of C. chinense regenerants showed blue staining, suggesting expression of uidA. Incubated tissues of non-transformed regenerants did not show blue staining in phosphate buffer pH 8. The results show that for transformation experiments of C. chinense with uidA gene, pH 8 is recommended for histochemical staining.

Minilaparoscopia diagnóstica en pacientes con dolor abdominal agudo / Dignosis minilaparoscopy in patients with acute abdominal pain

Estudio prospectivo para demostrar la utilidad de la minilaparoscopia como método diagnóstico en la evaluación de pacientes con dolor abdominal agudo y diagnóstico clínico impreciso. Treinta (30) pacientes con dolor abdominal agudo, 22 (73,33 por ciento) mujeres y 8 (26,67 por ciento) hombres con edad promedio de 27 años, bajo diversas modalidades anestésicas, fueron sometidos a microlaparoscopia de emergencia, desde 17/7/2001 hasta 17/4/2002. Hospital Central "Dr. Antonio José Urquinaona" de Maracaibo, Venezuela (Kurskall-Wallis). El procedimiento fue útil en 29 (96,67 por ciento) pacientes al demostrar alteraciones directas o indirectas de patología intraabdominal en 27 casos (90 por ciento) y descartarlos en 2 casos (6,66 por ciento) con probable patología renoureteral. Solamente hubo una falla del método (3,34 por ciento) al no diagnosticarse un caso de apendicitis aguda retrocecal incipiente que posteriormente se aclaró. El procedimiento endoscópico permitió precisar la conducta terapéutica en 27 (90 por ciento) casos: tratamiento médico en 6 (20 por ciento) pacientes con diagnóstico de enfermedad pélvica inflamatoria; aspiración inmediata de sangre libre en cavidad abdominal en 5 (16,67 por ciento) pacientes, 4 (80 por ciento) con ruptura de quistes ováricos y uno (20 por ciento) con ascitis hemorrágica, e intervención quirúrgica a los restantes 16 (53,33 por ciento) pacientes 15 (93,75 por ciento) con diagnóstico de apendicitis aguda y uno (6,25 por ciento) con quiste paraovárico derecho torcido. No hubo complicaciones en el procedimiento. La miniolaparoscopia es un método eficaz en la valoración de pacientes con dolor abdominal agudo y diagnóstico clínico impreciso

Prolapso rectal: corrección transvaginal un nuevo procedimiento / Rectal prolapse: transvaginal correction a new procedure

Describir una forma de abordaje y procedimiento quirúrgico para la corrección del prolapso rectal en pacientes del sexo femenino. Se utiliza la vía transvaginal para colocar una banda de polipropileno alrededor del recto en el espacio pelviperitoneal superior con fijación de sus extremos a los fascículos puborrectales de los músculos elevadores que se aproximan por delante del recto, con suturas separadas. De esta manera la prótesis ejerce su acción en el lugar que suceden los cambios anatómicos y fisipatológicos que permiten la intususcepción y exteriorización del recto, limitado la capacidad receptiva de su ampolla y recuperando la propiedad de contención por la restitución adicional del ángulo anorectal posterior. La realización de esta técnica se lleva a cabo en posición ginecológica con anestesia conductiva. Servicio de Cirugía General 2, Hospital Central Dr. Antonio José Urquinaona de Maracaibo. La evolución ha sido satisfactoria en todas las pacientes, sin complicaciones inmediatas ni tardías. El control esfinteriano completo se recuperó en días. Los controles de más de 12 meses en 2 casos y de 6 años en el otro no revelan recidiva del prolapso rectal. La técnica impide una nueva invaginación, deslizamiento y exteriorización del recto. Presenta la facilidad de ejecución de los procedimientos perineales de retención, con las ventajas en los resultados de los procedimientos abdominales de suspensión. Permite, en un solo tiempo, corregir algunas alteraciones uroginecológicas y otras concomitantes del piso pélvico