Transcriptional analysis in bacteriophage Fc02 of Pseudomonas aeruginosa revealed two overlapping genes with exclusion activity.

Little is known about the gene expression program during the transition from lysogenic to lytic cycles of temperate bacteriophages in Pseudomonas aeruginosa. To investigate this issue, we developed a thermo-sensitive repressor mutant in a lysogen and analyzed the phage transcriptional program by strand-specific RNA-Seq before and after thermo-induction. As expected, the repressor gene located on the phage DNA forward strand is transcribed in the lysogen at the permissive temperature of 30°C. Upstream the repressor gene, we noticed the presence of two overlapped ORFs apparently in the same transcript. One ORF is a gene that encodes a protein of 7.9 kDa mediating the exclusion of various super-infecting phages. The other ORF, placed in an alternate reading frame with a possible AUG initiation codon at 25 nucleotide downstream of the AUG of the first gene, is expected to encode a 20.7 kDa polypeptide of yet an unknown function. Upon lifting repression at 40°C, the transcription of an operon which is involved in the lytic cycle is started from a promoter on the reverse phage DNA strand. The first gene in the operon is a homolog of the antirepresor ner, a common gene in the lysis-lysogeny regulation region of other phages. Interestingly, the next gene after ner is gene 10 that on the reverse strand overlaps the overlapped gene olg1 on the forward strand. Curiously, gene 10 expression also shows superinfection exclusion. Strand-specific RNA-Seq also has uncovered the transcription succession of gene modules expressed during the phage lytic stage. The conservation of overlapped genes with similar functions may be evolutionarily selected.

Primer registro de un caso de loxoscelismo cutáneo ocasionado por mordedura de araña violinista (Loxosceles yucatana) en Yucatán, México / First record of a case of cutaneous loxoscelism caused by violin spider (Loxosceles yucatana) bite in Yucatan, Mexico

El loxoscelismo es ocasionado cuando el veneno dermonecrótico producido por las arañas del género Loxosceles, conocidas como «arañas violinistas», ingresa al organismo de una persona a través de su mordida. En México ocurre un subregistro de los casos de loxoscelismo por la ausencia de pruebas de laboratorio para su diagnóstico y la dificultad del cuadro clínico. El objetivo de este trabajo es describir un caso de loxoscelismo cutáneo ocasionado por mordedura de Loxosceles yucatana en un residente de Yucatán, México. El loxoscelismo cutáneo es el tipo más frecuente y menos severo. El presente caso se diagnosticó por medio de la sintomatología registrada en la historia clínica, la lesión inicial y la identificación de arañas L. yucatana. Este trabajo representa la primera descripción de un caso de loxoscelismo cutáneo con resolución favorable en Yucatán.

Loxoscelism occurs when the dermonecrotic venom produced by spiders of the genus Loxosceles, known as "violin spiders," enters a person's organism through their bite. In Mexico there is an underreporting of loxoscelism cases due to the absence of laboratory tests for its diagnosis and the complexity of the clinical picture. The aim of this paper is to describe a case of cutaneous loxoscelism caused by the bite of Loxosceles yucatana in a resident of Yucatan, Mexico. Cutaneous loxoscelism is the most frequent and less severe type. This case was diagnosed by means of the symptomatology registered in the medical records, the initial lesion, and the identification of L. yucatana spiders. This study represents the first description of a case of cutaneous loxoscelism with favorable outcome in Yucatan.

Preditores de Mortalidade Hospitalar nos Pacientes Tratados por Angioplastia Primária: Um Estudo de Caso-Controle Multicêntrico / Predictors of Hospital Mortality Based on Primary Angioplasty Treatment: A Multicenter Case-Control Study

Resumo Fundamento A estratificação do risco de morte dos pacientes no contexto da angioplastia primária (ATC) é fundamental. Objetivo Identificar os fatores relacionados ao desfecho morte em pacientes submetidos a ATC. Métodos Estudo de caso-controle, utilizando como fonte de dados um registro brasileiro. A associação entre cada variável e o desfecho óbito foi avaliada via modelo de regressão logística binária. Consideramos significativo p<0,05. Resultados Foram analisados 26.990 registros, sendo 18.834 (69,8%) do sexo masculino, com idade mediana de 61 (17) anos. Na análise multivariada, as principais variáveis relacionadas ao desfecho óbito com seus respectivos odds ratio e intervalos de confiança (IC) com nível de significância de 95% foram a idade avançada 70 - 79 anos (2,46; 1,64 - 3,79) e ≥ 80 anos (3,68; 2,38 - 5,81), p<0,001, classificação de Killip II (2,71; 1,92 - 3,83), Killip III (8,14; 5,67 - 11,64), Killip IV (19,83; 14,85 - 26,69), p<0,001, disfunção global acentuada do ventrículo esquerdo (VE) (3,63; 2,39 - 5,68), p<0,001 e ocorrência de infarto após a intervenção (5,01; 2,57- 9,46), p<0,001. O principal fator protetor foi o fluxo TIMI III pós-intervenção (0,18; 0,13 - 0,24), p<0,001, seguido do TIMI II (0,59; 0,41 - 0,86), p=0,005, sexo masculino (0,79; 0,64 - 0,98), p= 0,032, dislipidemia (0,69; 0,59 - 0,85), p<0,001 e número de lesões tratadas (0,86; 0,9 - 0,94), p<0,001. Conclusão Os preditores de mortalidade nos pacientes submetidos a ATC foram: classificação de Killip, reinfarto, idade, disfunção global acentuada do VE, sexo feminino e fluxo TIMI 0/I pós-intervenção.

Abstract Background Identification of high-risk patients undergoing primary angioplasty (PCI) is essential. Objective Identify factors related to the causes of death in PCI patients. Methods This work consisted of a multicenter case-control study using a Brazilian registry of cardiovascular interventions as the data source. The association between each variable and death was assessed using a binary logistic regression model, p <0.05 was considered significant. Results A total of 26,990 records were analyzed, of which 18,834 (69.8%) were male patients, with a median age of 61 (±17) years. In the multivariate analysis, the main variables related to the causes of death with their respective odds ratios and 95%confidence intervals (CI) were advanced age, 70-79 years (2.46; 1.64-3.79) and ≥ 80 years (3.69; 2.38-5.81), p<0.001; the classification of Killip II (2.71; 1.92-3.83), Killip III (8.14; 5.67-11.64), and Killip IV (19.83; 14.85-26.69), p<0.001; accentuated global dysfunction (3.63; 2,39-5.68), p<0.001; and the occurrence of infarction after intervention (5.01; 2.57-9.46), p<0.001. The main protective factor was the post-intervention thrombolysis in myocardial infarction (TIMI) III flow (0.18; 0.13-0.24), p<0.001, followed by TIMI II (0.59; 0.41 -0.86), p=0.005, and male (0.79; 0.64-0.98), p = 0.032; dyslipidemia (0.69; 0.59-0.85), p<0.001; and number of lesions treated (0.86; 0.9-0.94), p<0.001. Conclusion The predictors of mortality in patients undergoing PCI were Killip's classification, reinfarction, advanced age, severe left ventricular dysfunction, female gender, and post-intervention TIMI 0 / I flow.

A YAP/TAZ-TEAD signalling module links endothelial nutrient acquisition to angiogenic growth.

Angiogenesis, the process by which endothelial cells (ECs) form new blood vessels from existing ones, is intimately linked to the tissue's metabolic milieu and often occurs at nutrient-deficient sites. However, ECs rely on sufficient metabolic resources to support growth and proliferation. How endothelial nutrient acquisition and usage are regulated is unknown. Here we show that these processes are instructed by Yes-associated protein 1 (YAP)/WW domain-containing transcription regulator 1 (WWTR1/TAZ)-transcriptional enhanced associate domain (TEAD): a transcriptional module whose function is highly responsive to changes in the tissue environment. ECs lacking YAP/TAZ or their transcriptional partners, TEAD1, 2 and 4 fail to divide, resulting in stunted vascular growth in mice. Conversely, activation of TAZ, the more abundant paralogue in ECs, boosts proliferation, leading to vascular hyperplasia. We find that YAP/TAZ promote angiogenesis by fuelling nutrient-dependent mTORC1 signalling. By orchestrating the transcription of a repertoire of cell-surface transporters, including the large neutral amino acid transporter SLC7A5, YAP/TAZ-TEAD stimulate the import of amino acids and other essential nutrients, thereby enabling mTORC1 activation. Dissociating mTORC1 from these nutrient inputs-elicited by the loss of Rag GTPases-inhibits mTORC1 activity and prevents YAP/TAZ-dependent vascular growth. Together, these findings define a pivotal role for YAP/TAZ-TEAD in controlling endothelial mTORC1 and illustrate the essentiality of coordinated nutrient fluxes in the vasculature.

Stem-cell transplantation for children with primary immune deficiencies: A retrospective study of 19 patients from one centre in Mexico.

INTRODUCTION: For many patients with primary immune deficiency (PID), stem-cell transplantation (SCT) may be life-saving. OBJECTIVE: To review our experience of 11 years transplanting children with PID in Mexico. METHODS: Chart review of patients who underwent SCT from 2008 to 2018, to describe their diagnoses, time to transplant, conditioning regime, survival rate and outcomes. All patients received post-transplant cyclophosphamide as graft-versus-host-disease (GVHD) prophylaxis. RESULTS: 19 patients with combined, phagocytic or syndromic PID from 5 states. Twelve of them were male (58%) and 14 survive (79%). Mean age at HSCT was 41.9 months; mean time from diagnosis was 31.2 months. Seven grafts were umbilical cord and 12 haploidentical. The conditioning regime was myeloablative, with five primary graft failures. Two patients had partial and 10 full chimerism. Five patients died within 2 months after transplant. Immune reconstitution was complete in 11 of 19 patients. We found a prevalence of 21% GVHD. DISCUSSION: We describe 19 patients from Mexico with 8 PID diagnoses who underwent allogenic HSCT over a period of 11 years. Survival rate and other outcomes compare well with industrialized countries. We recommend the use of post-transplant cyclophosphamide to prevent GVHD in scenarios of resource scarcity and a lack of HLA-identical donors.

Natural infection with Trypanosoma cruzi in bats captured in Campeche and Yucatán, México / Infección natural con Trypanosoma cruzi en murciélagos capturados en Campeche y Yucatán, México

Abstract | Introduction: Bats have been reported as hosts of the Trypanosoma cruzi protozoan, the etiologic agent of American trypanosomiasis, an endemic zoonotic disease in México. Objective: To describe T. cruzi infection in bats from the states of Campeche and Yucatán, México. Materials and methods: Captures were made from March to November, 2017 at three sites in Yucatán and one in Campeche. Up to four mist nets on two consecutive nights were used for the capture. The bats' species were identified and euthanasia was performed to collect kidney and heart samples for total DNA extraction. Trypanosoma cruzi infection was detected by conventional PCR with the amplification of a fragment belonging to the T. cruzi DNA nuclear. Results: Eighty-six bats belonging to five families (Vespertilionidae, Noctilionidae, Mormoopidae, Phyllostomidae, and Molossidae) and 13 species (Rhogeessa aeneus, Noctilio leporinus, Pteronotus davyi, P. parnellii, Artibeus jamaicensis, A. lituratus, A. phaeotis, Glossophaga soricina, Carollia sowelli, Chiroderma villosum, Uroderma bilobatum, Sturnira parvidens, and Molossus rufus) were captured. Infection frequency by PCR was 30,2% (26/86) detected only in the renal tissue. The infected species were P. parnellii, G. soricina, A. lituratus, A. jamaicensis, S. parvidens, C. villosum, and R. aeneus. Conclusions: Our results confirmed the participation of several bat species as hosts in the T. cruzi transmission cycle in the region. Further studies are necessary to establish the importance of these animals in the zoonotic transmission of T. cruzi.

Resumen | Introducción. Los murciélagos se han reportado como huéspedes del protozoario Trypanosoma cruzi, agente etiológico de la tripanosomiasis americana, enfermedad zoonótica endémica en México. Objetivo. Describir la infección con T. cruzi en murciélagos capturados en los estados de Campeche y Yucatán, México. Materiales y métodos. Se realizaron capturas de marzo a noviembre de 2017 en tres sitios de Yucatán y uno de Campeche. Para la captura se emplearon hasta cuatro redes de niebla por dos noches consecutivas. Se identificó la especie de los murciélagos capturados y se les practicó la eutanasia para recolectar muestras de riñón y corazón, utilizadas posteriormente en la extracción de ADN total. La infección con T. cruzi se detectó por la amplificación con PCR convencional de un fragmento perteneciente al ADN nuclear de T. cruzi. Resultados. Se capturaron 86 murciélagos pertenecientes a cinco familias (Vespertilionidae, Noctilionidae, Mormoopidae, Phyllostomidae, Molossidae) y 13 especies (Rhogeessa aeneus, Noctilio leporinus, Pteronotus davyi, P. parnellii, Artibeus jamaicensis, A. lituratus, A. phaeotis, Glossophaga soricina, Carollia sowelli, Chiroderma villosum, Uroderma bilobatum, Sturnira parvidens y Molossus rufus). La PCR mostró una frecuencia de infección de 30,2 % (26/86), detectada únicamente en tejido renal. Las especies infectadas fueron P. parnellii, G. soricina, A. lituratus, A. jamaicensis, S. parvidens, C. villosum y R. aeneus. Conclusiones. Los resultados confirmaron la participación de varias especies de murciélagos como huéspedes en el ciclo de transmisión de T. cruzi en la región. Es necesario realizar más estudios para determinar la importancia de estos animales en la transmisión zoonótica de T. cruzi.

Control of endothelial quiescence by FOXO-regulated metabolites.

Endothelial cells (ECs) adapt their metabolism to enable the growth of new blood vessels, but little is known how ECs regulate metabolism to adopt a quiescent state. Here, we show that the metabolite S-2-hydroxyglutarate (S-2HG) plays a crucial role in the regulation of endothelial quiescence. We find that S-2HG is produced in ECs after activation of the transcription factor forkhead box O1 (FOXO1), where it limits cell cycle progression, metabolic activity and vascular expansion. FOXO1 stimulates S-2HG production by inhibiting the mitochondrial enzyme 2-oxoglutarate dehydrogenase. This inhibition relies on branched-chain amino acid catabolites such as 3-methyl-2-oxovalerate, which increase in ECs with activated FOXO1. Treatment of ECs with 3-methyl-2-oxovalerate elicits S-2HG production and suppresses proliferation, causing vascular rarefaction in mice. Our findings identify a metabolic programme that promotes the acquisition of a quiescent endothelial state and highlight the role of metabolites as signalling molecules in the endothelium.

PIK3CA and CCM mutations fuel cavernomas through a cancer-like mechanism.

Vascular malformations are thought to be monogenic disorders that result in dysregulated growth of blood vessels. In the brain, cerebral cavernous malformations (CCMs) arise owing to inactivation of the endothelial CCM protein complex, which is required to dampen the activity of the kinase MEKK31-4. Environmental factors can explain differences in the natural history of CCMs between individuals5, but why single CCMs often exhibit sudden, rapid growth, culminating in strokes or seizures, is unknown. Here we show that growth of CCMs requires increased signalling through the phosphatidylinositol-3-kinase (PI3K)-mTOR pathway as well as loss of function of the CCM complex. We identify somatic gain-of-function mutations in PIK3CA and loss-of-function mutations in the CCM complex in the same cells in a majority of human CCMs. Using mouse models, we show that growth of CCMs requires both PI3K gain of function and CCM loss of function in endothelial cells, and that both CCM loss of function and increased expression of the transcription factor KLF4 (a downstream effector of MEKK3) augment mTOR signalling in endothelial cells. Consistent with these findings, the mTORC1 inhibitor rapamycin effectively blocks the formation of CCMs in mouse models. We establish a three-hit mechanism analogous to cancer, in which aggressive vascular malformations arise through the loss of vascular 'suppressor genes' that constrain vessel growth and gain of a vascular 'oncogene' that stimulates excess vessel growth. These findings suggest that aggressive CCMs could be treated using clinically approved mTORC1 inhibitors.

Detección de Aedes (Stegomyia) albopictus (Skuse) en ovitrampas en Mérida, México / Detection of Aedes (Stegomyia) albopictus (Skuse) in ovitraps of Mérida city, México

Resumen | Introducción. El programa de enfermedades transmitidas por vectores en México tiene una red establecida de ovitrampas para la vigilancia entomológica de Aedes spp. Los servicios de salud del estado de Yucatán, en respuesta a reportes de Aedes albopictus en la periferia de Mérida, capital del estado, incrementaron la especificidad de dicha vigilancia. Objetivo. Describir la presencia y distribución de Ae. albopictus en Mérida y su abundancia relativa comparada con Aedes aegypti, en ovitrampas del programa de control de vectores. Materiales y métodos. Durante octubre de 2019, se seleccionaron al azar 91 ovitrampas en 31 barrios de Mérida. Los mosquitos adultos se obtuvieron del insectario de la Unidad Colaborativa para Bioensayos Entomológicos de la Universidad Autónoma de Yucatán a partir de huevos recolectados en campo. Se determinó la abundancia relativa de individuos adultos de cada especie identificada y por barrios evaluados. Resultados. En el 32 % de los barrios muestreados, se detectó Ae. albopictus y, en todos ellos, Ae. aegypti. Se recolectaron 28 adultos de Ae. albopictus (10 hembras y 18 machos) en las ovitrampas. No se observó correlación entre la abundancia de adultos ni de hembras Ae. aegypti y Ae. albopictus por barrio (p>0,05). Conclusiones. Los resultados confirmaron que Ae. albopictus estaba coexistiendo con Ae.aegypti en Mérida en el momento del estudio. La baja abundancia relativa sugiere que Ae.albopictus se encontraba en la fase inicial de invasión.

Abstract | Introduction:The vector-borne diseases program in México has an established network of ovitraps for entomological surveillance of Aedes spp. In response to reports of Aedes albopictus in the periphery of Mérida, the state capital of Yucatán, the Ministry of Health increased the specificity of this surveillance. Objective: To describe the presence and distribution of Ae. albopictus in Mérida and its relative abundance compared to Aedesaegypti in ovitraps of the vector control program. Materials and methods: During October, 2019, 91 ovitraps were randomly selected from 31 neighborhoods of Mérida. Mosquitoes were reared at the insectary of the Collaborative Unit for Entomological Bioassays of the Autonomous University of Yucatán from eggs collected in the field. Relative abundance was determined for adult individuals of each identified species and neighborhood. Results: 32 % of the neighborhoods were positive for Ae. albopictus and 100 % for Ae. aegypti. A total of 28 adults of Ae. albopictus (10 females and 18 males) were obtained from ovitraps. No correlation was observed between the abundance of Ae. aegypti and Ae. albopictus for both adults and females (p>0.05) at the neighborhood level. Conclusions: The results confirm that Ae. albopictus coexisted with Ae. aegypti in Mérida at the time of the study. The low relative abundance suggests that Ae. albopictus was in the initial phase of invasion.

The genus Rickettsia in Mexico: Current knowledge and perspectives.

The genus Rickettsia encompasses 35 valid species of intracellular, coccobacilli bacteria that can infect several eukaryotic taxa, causing multiple emerging and re-emerging diseases worldwide. This work aimed to gather and summarise the current knowledge about the genus Rickettsia in Mexico, updating the taxonomy of the bacteria and their hosts by including all the records available until 2020, to elucidate host-parasite relationships and determine the geographical distribution of each Rickettsia species present in the country. Until now, 14 species of Rickettsia belonging to four groups have been recorded in Mexico. These species have been associated with 26 arthropod species (14 hard ticks, three soft ticks, two sucking lice, and seven fleas) and 17 mammal species distributed over 30 states in Mexico. This work highlights the high biological inventory of rickettsias for Mexico and reinforces the need to approach the study of this group from a One Health perspective.

Crop management and its effects on weed occurrence

The objective was to evaluate weed phytosociology and similarities between crop management systems in the Chapadões region. The experiment was conducted at in agricultural area located in the municipality of Chapadão do Sul, MS, during the 2016/17 harvest. Three crop managements strategies were used: (1) cotton/soybean/Urochloa, (2) millet/soybean/millet and (3) millet/soybean/crotalaria. A phytosociological survey of weeds was carried out during soybean cultivation and cover crops growth, in succession. The evaluation area for each management strategy was 0.5 ha. Soybean surveys were carried out in October and January, while the cover crop surveys were performed in February and May. The relative frequency (RF), relative density (RD), relative abundance (AR), and relative importance (RI) of weeds, Venn diagram, and Jaccard and Sorenson similarity indices were evaluated. The management area represented by the cotton/soybean/Urochloa rotation had fewer weed species than others. The species Cenchrus echinatus, Digitaria insularis, Digitaria sanguinalis, Eleusine indica and Commelina benghalensis had the highest phytosociological indeces among the monocotyledons. Attention is required for managing the dicotyledons Amaranthus deflexus, Conyza canadensis and Senna obtusifolia despite their low indices because of herbicide resistant cases. The highest indeces of similarity were found between managements areas 2 and 3, which did not rely on cotton cultivation prior to soybeans.

Leptospira patógena en murciélagos de Campeche y Yucatán, México / Pathogenic Leptospira in bats from Campeche and Yucatán, Mexico

RESUMEN Objetivo. Reportar la infección con Leptospira en ríñones de murciélagos de Campeche y Yucatán, México, a través de la amplificación por PCR de dos fragmentos distintos del gen 16S RNA ribosomal. Materiales y métodos. Se realizaron capturas en un sitio de Campeche y dos de Yucatán. A los murciélagos capturados se les aplicó la eutanasia y se les realizó una necropsia para recolectar tejido renal que se usó en la extracción de ADN total. Se realizaron dos PCR convencionales para la amplificación de los fragmentos de 16S RNA ribosomal. Se obtuvieron las secuencias de algunos productos positivos y se analizaron con herramientas bioinformáticas para identificar la especie infectante de Leptospira. Resultados. Se capturaron 69 murciélagos pertenecientes a cuatro familias y a ocho especies distintas. La familia con mayor diversidad fue Phyllostomidae con cinco especies. La especie con mayor frecuencia de captura fue Artibeusjamaicensis (41, 59.4%). Las PCR arrojaron una frecuencia global de infección de 21.7%. Las especies infectadas fueron A. jamaicensis, Pteronotus parnellii y Chiroderma villosum. El análisis bioinformático arrojó un 99.0% de identidad para Leptospira noguchii, Leptospira borgpetersenii y Leptospira santarosai. Conclusiones. Algunas especies de murciélagos de Yucatán y Campeche son portadores renales de leptospiras patógenas, por lo que podrían participar en el ciclo silvestre de transmisión en la región. La frecuencia de infección encontrada en los riñones de los murciélagos utilizados es mayor en comparación con aquellas obtenidas en otros reservorios de Yucatán y Campeche. Nuevas especies de murciélagos son reportadas como portadores de Leptospira para México.

ABSTRACT Objective. To report the infection with Leptospira in the kidneys of bats from Campeche and Yucatán, Mexico, through the amplification by PCR of two different 16S RNA ribosomal gene fragments. Materials and methods. Bat captures were carried out at one site in Campeche and two sites in Yucatán. Euthanasia was applied to the captured bats and a necropsy was performed to collect a renal tissue sample that was used in the total DNA extraction. Two different conventional PCR were performed for the amplification of the 16S RNA ribosomal gene fragments. Some sequences from positive products were obtained and analyzed with bioinformatics tools to identify the infectious species of Leptospira. Results. Sixty-nine bats belonging to four families and eight different species were captured. The family with the greatest diversity was Phyllostomidae with five species. The most captured species was Artibeus jamaicensis (41, 59.4%). Both PCR showed a global infection frequency of 21.7%. The infected species were A. jamaicensis, Pteronotus parnellii, and Chiroderma villosum. The bioinformatic analysis of the positive products yielded a 99.0% identity for Leptospira noguchii, Leptospira borgpetersenii, and Leptospira santarosai. Conclusions. Some bat species of Yucatán and Campeche, Mexico, are renal carriers of pathogenic Leptospira, therefore participating in the transmission cycle in the region. The frequency of infection found in the renal tissue of the captured bats is higher than the one obtained from other reservoirs captured in Yucatán and Campeche. New species of bats are reported as renal Leptospira carriers in Mexico.

Endothelial Cells Don't Waste: Endothelial-Derived Lactate Boosts Muscle Regeneration.

Blood vessels are an essential interface between the circulation and tissue that deploy signaling molecules (angiocrines) for organ development, homeostasis, and repair. In a recent issue of Cell Metabolism, Zhang et al. (2020) identify lactate as an endothelial-derived signal promoting ischemic muscle regeneration, establishing metabolites as a new angiocrine class.

Estudio histopatológico de tejido cardiaco de roedores infectados con Trypanosoma cruzi capturados en barrios suburbanos de Mérida, México / Histopathological study in cardiac tissue of rodents infected with Trypanosoma cruzi, captured in suburbs of Mérida, México

Resumen Introducción. Trypanosoma cruzi es el agente causal de la tripanosomiasis americana, enfermedad endémica en México. Los roedores Mus musculus y Rattus rattus son reservorios del parásito, el cual invade las fibras cardiacas y desarrolla nidos parasitarios produciendo diversas lesiones. Los estudios histopatológicos en roedores naturalmente infectados son escasos. Objetivo. Describir los tipos y las frecuencias de las lesiones microscópicas en muestras de tejido cardiaco de M. musculus y R. rattus infectados con T. cruzi capturados en Mérida, México. Materiales y métodos. Los roedores se capturaron en los barrios suburbanos de Mérida. Se extrajo el tejido cardiaco y se procesó por la técnica de inclusión en parafina y tinción con hematoxilina y eosina. Su examen se hizo con un microscópico convencional y se determinaron todas las lesiones y su grado de afección. Resultados. Se trabajaron ocho muestras de tejido de M. musculus y siete de R. rattus. Se encontraron nidos parasitarios en siete del total de las muestras: en 3 de las 8 de M. musculus y en 4 de las 7 de R. rattus. Se observaron infiltrados inflamatorios en todas las muestras. Otras lesiones fueron la degeneración de las fibras cardiacas (8/15), la congestión de los vasos sanguíneos (6/15) y la necrosis (5/15). Discusión. Las lesiones observadas están descritas en los modelos animales experimentales y en los humanos con tripanosomiasis americana. Los infiltrados inflamatorios se han descrito como la lesión más significativa en los humanos y en los reservorios en la etapa crónica de la enfermedad. Conclusión. Las lesiones observadas están asociadas con la infección con T. cruzi, lo cual confirma que los roedores estudiados son reservorios de este parásito.

Abstract Introduction: Trypanosoma cruzi is the causal agent of the American trypanosomiasis, an endemic disease in México. The commensal rodents Mus musculus and Rattus rattus are reservoirs of this parasite, which invades cardiac fibers and develops parasite nests causing various lesions. Histopathological studies in naturally infected rodents are scarce. Objective: To describe the types and frequencies of microscopic lesions in cardiac tissue of M. musculus and R. rattus infected with T. cruzi captured in Mérida, México. Materials and methods: The rodents were captured in suburban environments of Mérida. Cardiac tissue was extracted and processed by the paraffin inclusion technique and hematoxylin and eosin stained. The observation was made with a conventional microscope and all the lesions, as well as their degree, were identified. Results: Eight tissue samples of M. musculus and seven of R. rattus were studied. Parasite nests were found in 7/15, specifically 3/8 in M. musculus and 4/7 in R. rattus. The inflammatory infiltrate was the most frequent lesion. Other lesions were: Degeneration of cardiac fibers (8/15), congestion of blood vessels (6/15), and necrosis (5/15). Discussion: The lesions we observed have been described in experimental animal models and in humans with American trypanosomiasis. The inflammatory infiltrate has been identified as the most significant lesion in humans and reservoirs in the chronic stage of the disease. Conclusion: The lesions we described are associated with T. cruzi infection, which confirms that the rodents studied are reservoirs of this parasite.

Rickettsia spp. en garrapatas (Acari: Ixodidae) que infestan perros de una comunidad rural con antecedentes de rickettsiosis, Yucatán, México / Rickettsia spp. in ticks (Acari: Ixodidae) infesting dogs from a rural community with rickettsial diseases reports, Yucatan, Mexico

RESUMEN Introducción: Las bacterias del género Rickettsia son agentes causales de las rickettsiosis, enfermedades zoonóticas transmitidas por ectoparásitos. En Yucatán, ocurrió un brote en habitantes de Bolmay, Valladolid; sin embargo, no se identificó el probable artrópodo vector. Objetivo: Analizar la presencia de Rickettsia spp. en garrapatas que infestan perros domésticos de Bolmay. Material y métodos: Se trabajaron 105 viales con hasta ocho garrapatas. Se extrajo ADN de los ectoparásitos, posterior a la identificación del estadio de desarrollo vital, sexo, género y especie. Se realizaron dos PCR para aislar fragmentos de los genes htrA (17-kDa) y rOmpB, pertenecientes a Rickettsia spp. Los productos positivos fueron secuenciados y analizados con la herramienta BLAST y el algoritmo Megablast. Resultados: Se utilizaron 291 garrapatas de los géneros Amblyomma (55.7%, 162/291), Rhipicephalus (34%, 99/291) e Ixodes (10.3%, 30/291), y las especies Rhipicephalus sanguineus sensu lato, Ixodes affinis y Amblyomma mixtum. La positividad por PCR fue de 11.4% (12/105) para los géneros Amblyomma (66.7%, 8/12), Rhipicephalus (25%, 3/12) e Ixodes (8.3%, 1/12), y las especies A. mixtum, Rh. sanguineus s. l. e I. affinis. Se identificó ADN rickettsial en ninfas, larvas, adultos, machos y hembras. Cada análisis BLAST arrojó un 96% de cobertura e identidad con varias secuencias de Rickettsia spp. como Rickettsia typhi, Rickettsia felis y Rickettsia prowazekii, por lo que no fue posible determinar la especie infectante. Conclusión: Las garrapatas que infestan perros de Bolmay, probablemente están involucrados en el ciclo de transmisión de Rickettsia spp. Se presenta la primera evidencia molecular de Rickettsia spp. en garrapatas I. affinis de Yucatán, México.

ABSTRACT Introduction: Bacteria of the Rickettsia genus are causal agents of the rickettsial diseases, zoonoses transmitted by ectoparasites. In Yucatan, in inhabitants from Bolmay an outbreak occurred; however, the probable vector was not identified. Objective: To analyze the Rickettsia spp. presence in ticks infesting domestic dogs from Bolmay. Material and methods: We used 105 vials with up to eight ticks. Total DNA from the ectoparasites was extracted, after the identification of the life stages, sex, gender, and species. Two PCR to isolate fragments of the htrA (17-kDa) and rOmpB genes belonging to Rickettsia spp., were performed. The positive products were sequenced and analyzed using the BLAST tool and the Megablast algorithm. Results: 291 ticks of the genera Amblyomma (55.7%, 162/291), Rhipicephalus (34%, 99/291), and Ixodes (10.3%, 30/291), and the species Rhipicephalus sanguineus sensu lato, Ixodes affinis, and Amblyomma mixtum, were used. The PCR positivity was 11.4% (12/105) for the genera Amblyomma (66.7%, 8/12), Rhipicephalus (25%, 3/12), and Ixodes (8.3%, 1/12), and the species A. mixtum, Rh. sanguineus s. l., and I. affinis. Rickettsial DNA in nymph, larva, adult, males, and females, were identified. Each BLAST analysis showed an identity and coverage of 96% with several Rickettsia spp. sequences, such as Rickettsia typhi, Rickettsia felis and Rickettsia prowazekii, so it was not possible to determine the infecting species. Conclusion: Ticks infesting dogs from Bolmay are probably involved in the transmission cycle of Rickettsia spp. The first molecular evidence of Rickettsia spp. in I. affinis ticks from Yucatan, Mexico, is presented.

Infección con Toxoplasma gondii (Eucoccidiorida: Sarcocystidae) en murciélagos de Campeche y Yucatán, México

Toxoplasma gondii es un protozoario parásito reconocido como el agente causal de la toxoplasmosis, enfermedad zoonótica que afecta a humanos y animales domésticos o silvestres. En México, representa un problema de salud pública y veterinaria, sobre todo en regiones con climas tropicales y subtropicales. Los murciélagos han sido identificados como hospederos accidentales en el ciclo de transmisión; no obstante, en México no existe información previa; por lo tanto, el objetivo del presente estudio es reportar la infección con T. gondii en murciélagos capturados en sitios de los estados de Campeche y Yucatán, México. Se capturaron murciélagos en dos sitios de Yucatán y uno de Campeche, ubicados en la Península de Yucatán. Se recolectaron riñones, bazo e hígado y se emplearon en la extracción de ADN total. La infección con T. gondii se detectó a través de la amplificación de un fragmento del gen B1, utilizando PCR anidada. Los productos positivos fueron purificados y enviados a secuenciación para su posterior análisis de alineamiento; adicionalmente, se construyó un árbol filogenético. Se analizaron un total de 69 murciélagos pertenecientes a ocho especies distintas: 41 (59.4 %, 41/69) Artibeus jamaicensis; seis (8.7 %, 6/69) Pteronotus parnellii; seis (8.7 %, 6/69) Noctilio leporinus; seis (8.7 %, 6/69) Chiroderma villosum; cuatro (5.8 %, 4/69) Glossophaga soricina; dos (2.9 %, 2/69) Carollia sowelli; dos (2.89 %, 2/69) Artibeus lituratus y dos (2.9%, 2/69) Rhogeessa aeneus. La PCR anidada identificó ocho (11.6 %, 8/69) murciélagos positivos a la infección: seis (75 %, 6/8) A. jamaicensis, capturados en X'matkuil y Panabá, un (12.5 %, 1/8) G. soricina y un (12.5 %, 1/8) C. villosum, ambos capturados en Panabá. El análisis de alineamiento arrojó 99-100 % para cobertura y 97-99 % para identidad respecto a secuencias de T. gondii. Nuestros resultados aportan al entendimiento del ciclo de transmisión de T. gondii en la región; sin embargo, son necesarias investigaciones futuras para determinar los genotipos circulantes, ya que estudios anteriores han demostrado que estos animales pueden estar infectados con genotipos identificados en otros animales domésticos o silvestres e incluso en humanos.

Toxoplasma gondii is a protozoan parasite recognized as the causative agent of toxoplasmosis, a zoonotic disease that affects humans and domestic or wild animals. In Mexico, it represents a public and animal health problem, especially in regions with tropical and subtropical climates. Bats have been reported as accidental hosts in the transmission cycle; however, there is no preceding information in Mexico. Therefore, the aim of the present study is to report the T. gondii infection in bats captured in sites of Campeche and Yucatan states, Mexico. Bats were captured in two sites in Yucatan (X'matkuil and Panaba) and one in Campeche (Hampolol), located in the Yucatan Peninsula. Kidneys, spleen, and liver were collected and used in the total DNA extraction. Toxoplasma gondii infection was detected through the amplification of a B1 gene fragment, using nested PCR. The positive PCR products were purified and sent to sequencing for a posterior sequence identity analysis. Additionally, a phylogenetic tree was made. A total of 69 bats belonging to eight different species were processed: 41 (59.4 %, 41/69) Artibeus jamaicensis; six (8.7 %, 6/69) Pteronotus parnellii; six (8.7 %, 6/69) Noctilio leporinus; six (8.7 %, 6/69) Chiroderma villosum; four (5.8 %, 4/69) Glossophaga soricina; two (2.9 %, 2/69) Carollia sowelli; two (2.89 %, 2/69) Artibeus lituratus; and two (2.9 %, 2/69) Rhogeessa aeneus. The nested PCR identified eight (11.6 %, 8/69) infected bats: six (75 %, 6/8) A. jamaicensis, captured in X'matkuil and Panaba, one (12.5 %, 1/8) G. soricina, and one (12.5 %, 1/8) C. villosum, both captured in Panaba. The alignment analysis yielded 99-100 % for cover and 97-99 % for identity to T. gondii sequences. Our results contribute to the understanding of the T. gondii transmission cycle in the region; however, future research is needed to determine circulating genotypes, as previous studies have demonstrated that these animals might be infected with identified genotypes in other domestic or wild animals and even in humans.

CDC42 Deletion Elicits Cerebral Vascular Malformations via Increased MEKK3-Dependent KLF4 Expression.

RATIONALE: Aberrant formation of blood vessels precedes a broad spectrum of vascular complications; however, the cellular and molecular events governing vascular malformations are not yet fully understood. OBJECTIVE: Here, we investigated the role of CDC42 (cell division cycle 42) during vascular morphogenesis and its relative importance for the development of cerebrovascular malformations. METHODS AND RESULTS: To avoid secondary systemic effects often associated with embryonic gene deletion, we generated an endothelial-specific and inducible knockout approach to study postnatal vascularization of the mouse brain. Postnatal endothelial-specific deletion of Cdc42 elicits cerebrovascular malformations reminiscent of cerebral cavernous malformations (CCMs). At the cellular level, loss of CDC42 function in brain endothelial cells (ECs) impairs their sprouting, branching morphogenesis, axial polarity, and normal dispersion within the brain tissue. Disruption of CDC42 does not alter EC proliferation, but malformations occur where EC proliferation is the most pronounced during brain development-the postnatal cerebellum-indicating that a high, naturally occurring EC proliferation provides a permissive state for the appearance of these malformations. Mechanistically, CDC42 depletion in ECs elicited increased MEKK3 (mitogen-activated protein kinase kinase kinase 3)-MEK5 (mitogen-activated protein kinase kinase 5)-ERK5 (extracellular signal-regulated kinase 5) signaling and consequent detrimental overexpression of KLF (Kruppel-like factor) 2 and KLF4, recapitulating the hallmark mechanism for CCM pathogenesis. Through genetic approaches, we demonstrate that the coinactivation of Klf4 reduces the severity of vascular malformations in Cdc42 mutant mice. Moreover, we show that CDC42 interacts with CCMs and that CCM3 promotes CDC42 activity in ECs. CONCLUSIONS: We show that endothelial-specific deletion of Cdc42 elicits CCM-like cerebrovascular malformations and that CDC42 is engaged in the CCM signaling network to restrain the MEKK3-MEK5-ERK5-KLF2/4 pathway.

Detección molecular de leptospiras patógenas en roedores sinantrópicos y silvestres capturados en Yucatán, México / Molecular detection of pathogenic Leptospira in synanthropic and wild rodents captured in Yucatán, México

Introducción. La leptospirosis es una enfermedad zoonótica endémica en México, ocasionada por la bacteria del género Leptospira, la cual constituye un problema de salud pública y veterinaria. Los roedores son los reservorios más relevantes de Leptospira spp., debido a que la bacteria se establece y se reproduce en su tejido renal y es excretada por la orina. Objetivo. Identificar la presencia de Leptospira spp. en tejido renal de roedores capturados en Yucatán, México. Materiales y métodos. Se capturaron roedores sinantrópicos y silvestres en el municipio rural de Cenotillo, Yucatán, México. Se tomó un riñón de cada roedor y se extrajo el ADN total. La identificación de Leptospira spp. se hizo mediante la detección de dos fragmentos del gen 16S rRNA con una reacción en cadena de la polimerasa (PCR) de punto final. Los productos positivos se secuenciaron y se analizaron con herramientas de alineamiento. Resultados. Se capturaron 92 roedores pertenecientes a siete especies distintas. La PCR arrojó 5,4 % (5/92) de positividad global. El análisis del alineamiento de los aislamientos de los roedores infectados demostró 100 % de cobertura e identidad con la especie Leptospira interrogans. Esta es la primera evidencia molecular de la circulación de Leptospira spp. en Heteromys gaumeri capturados en Yucatán, México. Conclusión. Se evidenció que los roedores de Yucatán, México, son reservorios de Leptospira spp. y participan en el ciclo de infección de la leptospirosis en la región.

Introduction: Leptospirosis is a zoonotic disease caused by bacteria of the genus Leptospira, which is endemic in México and considered a public and veterinary health problem. Rodents are the most relevant reservoirs of Leptospira spp. because the bacteria establish and reproduce in its renal tissue and are excreted through the urine. Objective: To identify the presence of Leptospira spp. in renal tissue from rodents captured in Yucatán, México. Materials and methods: Synanthropic and wild rodents were captured in the rural municipality of Cenotillo, Yucatán, México. We collected one kidney from each rodent and extracted the total DNA. The identification of Leptospira spp. was done by detecting two fragments of the 16S rRNA gene using end-point polymerase chain reaction (PCR). We sequenced and analyzed positive products using alignment tools. Results: A total of 92 rodents belonging to seven different species were captured. The PCR yielded a global positivity of 5.4% (5/92). The alignment analysis of the sequenced products demonstrated a 100% of coverage and identity with Leptospira interrogans. This is the first molecular evidence of Leptospira spp. circulation in Heteromys gaumeri captured in Yucatán, México. Conclusion: Our results evidenced that rodents of Yucatán are reservoirs of Leptospira spp. and participate in the infection cycle of leptospirosis in the region.