Determination of Vitamin A and its Metabolites in Rat Testis: Possible Involvement of Vitamin A in Testicular Toxicity Caused by Molinate

This study was conducted to evaluate the effect of molinate on retinoids homeostasis in rat testis. Molinate was administrated to male Sprague–Dawley rats (200 mg kg−1 in corn oil, ip). Retinoid measurements were made at 6, 12, 48 and 168 h time points after administration. Testis levels of retinoic acid decreased (32 %) in a statistically significant manner at the 12 and 48 h time points. However, retinol and retinaldehyde were not significantly affected by molinate. These results suggest that molinate affects retinoic acid synthesis in testis and could contribute to understanding the molecular mechanism of molinate involved testicular toxicity

Impact of flavonoid-rich black tea and beetroot juice on postprandial peripheral vascular resistance and glucose homeostasis in obese, insulin-resistant men: a randomized controlled trial.

BACKGROUND: Insulin-stimulated muscle blood flow facilitates plasma glucose disposal after a meal, a mechanism that is impaired in obese, insulin-resistant volunteers. Nitrate- or flavonoid-rich products, through their proposed effects on nitric oxide, may improve postprandial blood flow and, subsequently, glucose disposal. To investigate whether a single dose of nitrate-rich beetroot juice or flavonoid-rich black tea lowers postprandial muscle vascular resistance in obese volunteers and alters postprandial glucose or insulin concentrations. METHOD: In a randomised, controlled, cross-over study, 16 obese, insulin-resistant males consumed 75 g glucose, which was combined with 100 ml black tea, beetroot juice or control (water). Peripheral vascular resistance (VR), calculated as mean arterial pressure divided by blood flow, was assessed in the arm and leg conduit arteries, resistance arteries and muscle microcirculation across 3 h (every 30-min) after the oral glucose load. RESULTS: During control, we found no postprandial response in VR in conduit, resistance and microvessels (all P > 0.05). Black tea decreased VR compared to control in conduit, resistance and microvessels (all P < 0.05). Beetroot juice decreased postprandial VR in resistance vessels, but not in conduit artery and microvessels. Although postprandial glucose response was similar after all interventions, postprandial insulin response was attenuated by ~29 % after tea (P < 0.0005), but not beetroot juice. CONCLUSIONS: A single dose of black tea decreased peripheral VR across upper and lower limbs after a glucose load which was accompanied by a lower insulin response. Future studies in insulin-resistant subjects are warranted to confirm the observed effects and to explore whether long-term regular tea consumption affects glucose homeostasis. TRIAL REGISTRATION: The study was registered at clinicaltrials.gov on 30(th) November 2012 (NCT01746329)

TOPAZ1, a Novel Germ Cell-Specific Expressed Gene Conserved during Evolution across Vertebrates

BACKGROUND: We had previously reported that the Suppression Subtractive Hybridization (SSH) approach was relevant for the isolation of new mammalian genes involved in oogenesis and early follicle development. Some of these transcripts might be potential new oocyte and granulosa cell markers. We have now characterized one of them, named TOPAZ1 for the Testis and Ovary-specific PAZ domain gene. PRINCIPAL FINDINGS: Sheep and mouse TOPAZ1 mRNA have 4,803 bp and 4,962 bp open reading frames (20 exons), respectively, and encode putative TOPAZ1 proteins containing 1,600 and 1653 amino acids. They possess PAZ and CCCH domains. In sheep, TOPAZ1 mRNA is preferentially expressed in females during fetal life with a peak during prophase I of meiosis, and in males during adulthood. In the mouse, Topaz1 is a germ cell-specific gene. TOPAZ1 protein is highly conserved in vertebrates and specifically expressed in mouse and sheep gonads. It is localized in the cytoplasm of germ cells from the sheep fetal ovary and mouse adult testis. CONCLUSIONS: We have identified a novel PAZ-domain protein that is abundantly expressed in the gonads during germ cell meiosis. The expression pattern of TOPAZ1, and its high degree of conservation, suggests that it may play an important role in germ cell development. Further characterization of TOPAZ1 may elucidate the mechanisms involved in gametogenesis, and particularly in the RNA silencing process in the germ lin

Proliferating Cell Nuclear Antigen (PCNA) Regulates Primordial Follicle Assembly by Promoting Apoptosis of Oocytes in Fetal and Neonatal Mouse Ovaries

Primordial follicles, providing all the oocytes available to a female throughout her reproductive life, assemble in perinatal ovaries with individual oocytes surrounded by granulosa cells. In mammals including the mouse, most oocytes die by apoptosis during primordial follicle assembly, but factors that regulate oocyte death remain largely unknown. Proliferating cell nuclear antigen (PCNA), a key regulator in many essential cellular processes, was shown to be differentially expressed during these processes in mouse ovaries using 2D-PAGE and MALDI-TOF/TOF methodology. A V-shaped expression pattern of PCNA in both oocytes and somatic cells was observed during the development of fetal and neonatal mouse ovaries, decreasing from 13.5 to 18.5 dpc and increasing from 18.5 dpc to 5 dpp. This was closely correlated with the meiotic prophase I progression from pre-leptotene to pachytene and from pachytene to diplotene when primordial follicles started to assemble. Inhibition of the increase of PCNA expression by RNA interference in cultured 18.5 dpc mouse ovaries strikingly reduced the apoptosis of oocytes, accompanied by down-regulation of known pro-apoptotic genes, e.g. Bax, caspase-3, and TNFα and TNFR2, and up-regulation of Bcl-2, a known anti-apoptotic gene. Moreover, reduced expression of PCNA was observed to significantly increase primordial follicle assembly, but these primordial follicles contained fewer guanulosa cells. Similar results were obtained after down-regulation by RNA interference of Ing1b, a PCNA-binding protein in the UV-induced apoptosis regulation. Thus, our results demonstrate that PCNA regulates primordial follicle assembly by promoting apoptosis of oocytes in fetal and neonatal mouse ovaries

Effects of environmental Bisphenol A exposures on germ cell development and Leydig cell function in the human fetal testis

<div><p>Background</p><p>Using an organotypic culture system termed human Fetal Testis Assay (hFeTA) we previously showed that 0.01 μM BPA decreases basal, but not LH-stimulated, testosterone secreted by the first trimester human fetal testis. The present study was conducted to determine the potential for a long-term antiandrogenic effect of BPA using a xenograft model, and also to study the effect of BPA on germ cell development using both the hFETA and xenograft models.</p><p>Methods</p><p>Using the hFeTA system, first trimester testes were cultured for 3 days with 0.01 to 10 μM BPA. For xenografts, adult castrate male nude mice were injected with hCG and grafted with first trimester testes. Host mice received 10 μM BPA (~ 500 μg/kg/day) in their drinking water for 5 weeks. Plasma levels of total and unconjugated BPA were 0.10 μM and 0.038 μM respectively. Mice grafted with second trimester testes received 0.5 and 50 μg/kg/day BPA by oral gavage for 5 weeks.</p><p>Results</p><p>With first trimester human testes, using the hFeTA model, 10 μM BPA increased germ cell apoptosis. In xenografts, germ cell density was also reduced by BPA exposure. Importantly, BPA exposure significantly decreased the percentage of germ cells expressing the pluripotency marker AP-2γ, whilst the percentage of those expressing the pre-spermatogonial marker MAGE-A4 significantly increased. BPA exposure did not affect hCG-stimulated androgen production in first and second trimester xenografts as evaluated by both plasma testosterone level and seminal vesicle weight in host mice.</p><p>Conclusions</p><p>Exposure to BPA at environmentally relevant concentrations impairs germ cell development in first trimester human fetal testis, whilst gonadotrophin-stimulated testosterone production was unaffected in both first and second trimester testis. Studies using first trimester human fetal testis demonstrate the complementarity of the FeTA and xenograft models for determining the respective short-term and long term effects of environmental exposures.</p></div

Inactivation of the mouse adenylyl cyclase 3 gene disrupts male fertility and spermatozoon function

10.1210/me.2004-0318MOLECULAR ENDOCRINOLOGY1951277-129

Híbridos y progenitores de Sorgo tolerantes al frío, II: efecto de Fusarium verticillioides (Sacc.) Nirenberg en el rendimiento de semilla y sus componentes en condiciones de campo

The expansion of sorghum (Sorghum bicolor L. Moench) crop to the Central High Valleys of México, where cold tolerant experimental sorghum hybrids (CTESH) are already available, is limited by their susceptibility to stem and head blight (Fusarium verticillioides) and by the small seed size. The tolerance to this pathogen of new CTESH and some of their parental lines, to which this trait had been incorporated, was evaluated. In 2003, an experiment was established under field and irrigation conditions at Montecillo, State of México, in which 12 hybrids, 3 A-lines, 5 B-lines, 3 R-lines and the open pollinated variety VA-110 were evaluated. Three inoculation treatments at the onset of flowering, were applied per genotype: 1) injection of a pathogen suspension (5×104 conidia mL-1); 2) injection with sterile water; and 3) control without inoculum or injection. A complete randomized blocks design with three replicates, in a factorial arrangement, was used. The variables analyzed were: induced, natural and total damage caused by the pathogen on the vascular tissue, and its effect on dry matter production and distribution, and on seed yield and its components (100-seeds weight and number of seeds per panicle). The average temperature and relative humidity were favourable to the disease expression. On the average, the hybrids group produced more dry matter, higher seed yield per panicle and of its components than the groups of parental lines. The average values of heterosis and heterobeltiosis for seed yield per panicle were 35 and 22%. Some hybrids, and B and R-lines were found with less severe damage to vascular tissue and with lower yield and seed components reductions caused by the pathogen infection. The yield average and the seed size of the new parental lines were higher than those of VA-110. The results indicate that tolerance to F. verticillioides and greater seed size were traits successfully incorporated to new parental lines of cold tolerant sorghum hybridsLa expansión del cultivo del sorgo (Sorghum bicolor L. Moench) a los Valles Altos Centrales de México, donde ya existen sorgos híbridos experimentales tolerantes al frío (SHETF), está restringida por la susceptibilidad de éstos al tizón del tallo y de la panoja (Fusarium verticillioides) y su reducido tamaño de semilla. Se evaluó la tolerancia a este patógeno de nuevos SHETF y algunos de sus progenitores, a los cuales se había incorporado este carácter. En 2003 se estableció un experimento en Montecillo, Estado de México, en condiciones de campo y con riego, en el que se evaluaron 12 híbridos, 3 líneas A, 5 líneas B, 3 líneas R y la variedad VA-110; y tres tratamientos de inoculación al inicio de la floración: 1) inyección del patógeno en suspensión (5×104 conidios mL-1); 2) inyección con solamente agua estéril y 3) testigo sin inóculo ni inyección. El diseño fue bloques completos al azar con tres repeticiones, en arreglo factorial. Las variables analizadas fueron el daño artificial, natural y total originado por el patógeno al tejido vascular y su efecto en la producción y distribución de la materia seca y en el rendimiento de semilla y en sus componentes (peso de 100 semillas y número de semillas por panoja). Los promedios de temperatura y humedad relativa fueron favorables para la expresión del hongo. En promedio, el grupo de híbridos produjo más materia seca, mayor rendimiento de semilla por panoja y de sus componentes que los grupos de sus progenitores. Los valores promedio de heterosis y heterobeltiosis para rendimiento de semilla por panoja fueron 35 y 22%. Se identificaron híbridos y líneas B y R cuyos daños al tejido vascular provocados por la infección fueron menos severos y con menores reducciones en el rendimiento y en sus componentes. El promedio del rendimiento y del tamaño de semilla de los nuevos progenitores fue mayor que el de VA-110. Los resultados indican que la incorporación de tolerancia a F. verticillioides y de mayor tamaño de semilla, a las nuevas líneas progenitoras de híbridos de sorgo tolerantes al frío, ha sido satisfactoria

Híbridos y progenitores de sorgo tolerantes al frío. i: calidad de la semilla y su influencia en el establecimiento de plántulas

En parcelas de demostración establecidas en los Valles Altos Centrales de México, la emergencia de las plántulas de un primer grupo de sorgos híbridos tolerantes al frío fue lenta, lo que se atribuyó a las bajas temperaturas al inicio de la estación de crecimiento y al reducido peso de la semilla. En este estudio se evaluó la asociación entre algunas características de calidad de la semilla de nuevas líneas e híbridos experimentales de sorgo (Sorghum bicolor L. Moench) con las relacionadas con el establecimiento de las plántulas en campo, en 32 genotipos, agrupados en híbridos y sus progenitores: líneas A, B y R; y la variedad VA-110. En el laboratorio, la calidad de la semilla se evaluó con base en características fisiológicas (germinación y vigor de plántulas normales y anormales, entre otras); físicas (como peso de 100 semillas y peso volumétrico) y sanitarias (porcentaje de plántulas enfermas). En el campo, se consideró los días al inicio y al final de la emergencia, altura de plántula, velocidad de emergencia y porcentaje final de plántulas emergidas. En el laboratorio se estableció un diseño experimental completamente al azar y en campo se empleó un diseño de bloques completos al azar; en ambos casos se utilizaron tres repeticiones y los métodos propuestos por la ISTA para ensayos de semillas. El grupo de nuevos híbridos de sorgo presentó mayor peso de 100 semillas que el promedio de los grupos de progenitores, pero esa variable no mostró relación directa con mejores características de calidad de las líneas progenitoras. El menor peso de la semilla tampoco estuvo asociado con pobres atributos de germinación de la semilla, ni de emergencia de las plántulas en el campo. La mayoría de las variables medidas en las pruebas de laboratorio no correlacionaron linealmente con las variables de emergencia en campo. La temperatura del suelo no afectó la germinación de la semilla y emergencia de la plántula en campo en este estudio