Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 30
Filtrar
1.
Toxicon ; 242: 107712, 2024 May 06.
Artículo en Inglés | MEDLINE | ID: mdl-38614243

RESUMEN

Two outbreaks of pine needle abortions in cattle are here reported for the first time in Argentina. The cases occurred in Chubut and Neuquén provinces in the Patagonia region, causing 29.6% and 9% of abortions in each herd respectively. In both outbreaks, the dams were in the last third of gestation, and, due to a period of cold, snow and lack of available forage, they gained access to Pinus ponderosa and Pinus contorta forests. No pathological lesions, serological, molecular, or microbiological evidence of infectious causes were observed in any of the six fetuses analyzed. Microhistological analysis of feces confirmed higher presence of fragments of Pinus spp. needles in the diet of affected dams than in that of non-affected ones (12.2 vs 3.0%). Moreover, toxicological analysis showed higher tetrahydroagathic acid in the sera of affected dams than in that of non-affected ones (10.05 vs 2.81 ppm). In addition, this acid was detected in different fetal fluids (3.6-8.1 ppm) of the six fetuses analyzed. Interestingly, isocupressic acid was detected only in needles of P. ponderosa, and its content was lower than that found in other areas of the world (0.31 and 0.5% in Chubut and Neuquén respectively). These results confirm that the consumption of P. ponderosa by dams could have been the cause of these abortion outbreaks, a fact that should be considered as differential diagnosis in abortions of cattle, especially in silvopastoral systems of Argentina.


Asunto(s)
Aborto Veterinario , Enfermedades de los Bovinos , Pinus ponderosa , Bovinos , Animales , Argentina/epidemiología , Femenino , Enfermedades de los Bovinos/epidemiología , Aborto Veterinario/epidemiología , Embarazo , Hojas de la Planta , Intoxicación por Plantas/veterinaria , Intoxicación por Plantas/epidemiología , Brotes de Enfermedades/veterinaria
2.
Animal ; 15(7): 100235, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-34058597

RESUMEN

This study examined the use of an innovative tobacco variety, Nicotiana tabacum L., cv. Solaris, as forage. The whole plant biomass was ensiled, and the composition of SiloSolaris from bunker-silo and mini-silos was investigated. The effects of dietary inclusion of SiloSolaris on the growth, welfare, and nutritional profile of sixteen Holstein heifers, divided into two groups (n = 8), SiloSolaris (SS) and Control (CTR), were investigated. Heifers were group-fed diets with a 70:30 forage to concentrate ratio (on a DM basis). Both groups received 16.24 kg DM of concentrate mixture daily, including corn meal, wheat middlings and soybean meal. The CTR group was fed 39.43 kg DM of hay daily, and the SS group received 23.00 kg DM of the same hay and 12.69 kg DM SiloSolaris blended with the concentrate mixture. The feeding trial lasted eighty-one days with a thirty-six day adaptation phase. Data on forty-five days of diet administration are reported. At the end of the feeding trial, the plasma constituents of the heifers were studied. Moreover, heifers were monitored during a follow-up period, lasting up to 1 year after calving, for age at first insemination, age at first calving and daily milk yield. The SiloSolaris chemical composition showed an average DM content of 24.1 (±0.65) g/100 g. During ensiling, a decrease in CP and an increase in ammonia nitrogen contents were observed. The lactic acid content was variable (9.00 ± 2.66 g/100 g DM), while the acetic acid concentration was stable (4.27 ± 0.21 g/100 g DM). No butyric acid was detected in SiloSolaris, whose ammonia nitrogen content accounted for 15.7 (±1.86)% of the total nitrogen on average, and the mean pH value was 5.02 (±0.08). The SiloSolaris diet did not affect heifer growth performance. No differences were detected for body condition, fecal consistency, or locomotion scores. All the investigated plasma constituents were within or very close to the ranges reported for heifers; however, significant differences between the experimental groups were observed for triglycerides, cholesterol, albumin, and magnesium. The follow-up results did not differ between the experimental groups. These initial findings suggest that Nicotiana tabacum cv. Solaris is a promising ensiled forage for growing heifers that deserve to be further investigated.


Asunto(s)
Nicotiana , Ensilaje , Animales , Biomasa , Bovinos , Dieta/veterinaria , Digestión , Femenino , Estudios de Seguimiento , Rumen , Ensilaje/análisis , Zea mays
3.
Lett Appl Microbiol ; 69(6): 399-402, 2019 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-31618795

RESUMEN

The sugar glider (Petaurus breviceps) is a small, arboreal, nocturnal, gliding mammalian possum belonging to the marsupial infraclass. Exotic marsupials, including sugar gliders, are becoming popular companion pets and, consequently, the risk of potential infections that can be transmitted to humans should be investigated. Data on the role of the sugar glider as a possible carrier of pathogenic and zoonotic bacteria are scarce and fragmentary. Therefore, this study is aimed at evaluating the prevalence of potentially zoonotic bacteria (Salmonella spp., Escherichia coli, Campylobacter spp., Pseudomonas spp., Klebsiella spp., Listeria monocytogenes and Yersinia enterocolitica) in 64 sugar gliders kept as pets in Italy. The highest prevalence of infection pertained to members of the family Enterobacteriaceae, in particular Citrobacter spp. (50%), Enterobacter spp. (28·1%) and Klebsiella pneumoniae (15·6%); Pseudomonas aeruginosa was isolated from 10 out of 64 samples (15·6%). All strains of Klebsiella pneumoniae exhibited some level of resistance to multiple antimicrobials (ampicillin, amoxicillin-clavulanic acid and doxycycline). SIGNIFICANCE AND IMPACT OF THE STUDY: The results of this study show that sugar gliders may act as carriers of potentially pathogenic agents for humans and other animal species, therefore caution should be exercised in the handling and contact with these animals.


Asunto(s)
Farmacorresistencia Bacteriana Múltiple/fisiología , Enterobacteriaceae/efectos de los fármacos , Enterobacteriaceae/aislamiento & purificación , Marsupiales/microbiología , Mascotas/microbiología , Animales , Enterobacteriaceae/clasificación , Italia
4.
J Small Anim Pract ; 59(5): 294-297, 2018 May.
Artículo en Inglés | MEDLINE | ID: mdl-29315571

RESUMEN

OBJECTIVES: Reptiles are considered an important reservoir of Salmonella species. This study evaluated the prevalence of Salmonella species in different species of gecko kept as pets in Italy. MATERIALS AND METHODS: Faecal swab samples were collected from 70 clinically healthy geckos and examined for Salmonella species by culture that were then serotyped. RESULTS: Salmonella species were isolated from 24 of 70 (34·3%) samples. Eighteen isolates expressed resistance to ceftazidime and four isolates to ampicillin. CLINICAL SIGNIFICANCE: Salmonella spp. can be isolated from apparently healthy captive gecko which should be considered as a potential source of infection for humans and other companion animals.


Asunto(s)
Lagartos/microbiología , Salmonella/aislamiento & purificación , Animales , Farmacorresistencia Bacteriana , Heces/microbiología , Italia/epidemiología , Mascotas/microbiología , Salmonella/clasificación , Salmonelosis Animal/microbiología , Serotipificación
5.
Lett Appl Microbiol ; 58(5): 462-5, 2014 May.
Artículo en Inglés | MEDLINE | ID: mdl-24383854

RESUMEN

UNLABELLED: This study was aimed at evaluating the oral bacterial flora of 60 Python regius kept as pets by culture and biochemical methods. All isolates were also submitted to antimicrobial susceptibility testing using the disc diffusion method. The oral cavity of snakes sampled harboured a wide range of Gram-negative bacteria mainly constituted by Pseudomonas spp., Morganella morganii, Acinetobacter calcoaceticus, Aeromonas hydrophila, but also by Salmonella spp. Staphylococcus spp. was the commonest Gram-positive isolates, and various anaerobic Clostridium species were also found. The most effective antimicrobial agents were enrofloxacin and ciprofloxacin, followed by doxycycline and gentamicin. SIGNIFICANCE AND IMPACT OF THE STUDY: The oral cavity of snakes sampled harboured a wide range of bacteria. Our results suggest that people who come in contact with snakes could be at risk of infection and should follow proper hygiene practices when handling these reptiles.


Asunto(s)
Antibacterianos/farmacología , Boidae/microbiología , Clostridium/aislamiento & purificación , Bacterias Gramnegativas/aislamiento & purificación , Orofaringe/microbiología , Mascotas , Staphylococcus/aislamiento & purificación , Animales , Clostridium/clasificación , Femenino , Bacterias Gramnegativas/clasificación , Bacterias Gramnegativas/efectos de los fármacos , Humanos , Italia , Masculino , Zoonosis/microbiología
6.
Neurobiol Dis ; 38(3): 482-91, 2010 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-20149872

RESUMEN

Inflammation has been associated with the two classic lesions in the Alzheimer's (AD) brain, amyloid deposits and neurofibrillary tangles. Recent data suggest that Triflusal, a compound with potent anti-inflammatory effects in the central nervous system in vivo, might delay the conversion from amnestic mild cognitive impairment to a fully established clinical picture of dementia. In the present study, we investigated the effect of Triflusal on brain Abeta accumulation, neuroinflammation, axonal curvature and cognition in an AD transgenic mouse model (Tg2576). Triflusal treatment did not alter the total brain Abeta accumulation but significantly reduced dense-cored plaque load and associated glial cell proliferation, proinflammatory cytokine levels and abnormal axonal curvature, and rescued cognitive deficits in Tg2576 mice. Behavioral benefit was found to involve increased expression of c-fos and BDNF, two of the genes regulated by CREB, as part of the signal transduction cascade underlying the molecular basis of long-term potentiation. These results add preclinical evidence of a potentially beneficial effect of Triflusal in AD.


Asunto(s)
Enfermedad de Alzheimer/tratamiento farmacológico , Enfermedad de Alzheimer/metabolismo , Encéfalo/efectos de los fármacos , Encéfalo/metabolismo , Fármacos del Sistema Nervioso Central/farmacología , Salicilatos/farmacología , Enfermedad de Alzheimer/patología , Péptidos beta-Amiloides/genética , Péptidos beta-Amiloides/metabolismo , Animales , Axones/efectos de los fármacos , Axones/patología , Encéfalo/patología , Factor Neurotrófico Derivado del Encéfalo/metabolismo , Trastornos del Conocimiento/tratamiento farmacológico , Trastornos del Conocimiento/metabolismo , Trastornos del Conocimiento/patología , Citocinas/metabolismo , Modelos Animales de Enfermedad , Humanos , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Neuroglía/efectos de los fármacos , Neuroglía/patología , Placa Amiloide/efectos de los fármacos , Placa Amiloide/metabolismo , Placa Amiloide/patología , Proteínas Proto-Oncogénicas c-fos/metabolismo
7.
Lett Appl Microbiol ; 49(3): 351-3, 2009 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-19552770

RESUMEN

AIM: To estimate the prevalence of thermotolerant Campylobacter spp. in commercially reared partridges (Perdix perdix) in southern Italy. METHODS AND RESULTS: Cloacal swabs of partridges (n = 240), equally distributed between male and female birds, from a game bird farm located in the Southern Italy were examined for the prevalence of thermotolerant Campylobacter spp. The samples were processed in order to detect thermotolerant Campylobacter spp. by culture methods. The positive samples were then confirmed by multiplex polymerase chain reaction. Thermotolerant Campylobacter spp. were isolated from 118 (49.2%) of the 240 cloacal swabs examined. As proved by PCR, 100% of the strains were identified as Campylobacter coli (118/118), and 15 (12.7%) out of the 118 positive samples were also positive for Campylobacter jejuni. In contrast, Campylobacter lari was not identified. Adult partridges showed a significantly higher prevalence (P < 0.05) than younger ones. CONCLUSION: These results reinforce the assumption that game birds may be considered as potential carriers of Campylobacter spp. for human being and other animal species. SIGNIFICANCE AND IMPACT OF THE STUDY: Although an earlier 1986 publication described the prevalence of Campylobacter coli in commercially reared partridges, this is the first report to confirm the species of Campylobacter using a PCR test.


Asunto(s)
Infecciones por Campylobacter/veterinaria , Campylobacter coli/clasificación , Campylobacter coli/aislamiento & purificación , Campylobacter jejuni/clasificación , Campylobacter jejuni/aislamiento & purificación , Portador Sano/veterinaria , Galliformes/microbiología , Animales , Animales Domésticos/microbiología , Infecciones por Campylobacter/epidemiología , Infecciones por Campylobacter/microbiología , Campylobacter lari/clasificación , Campylobacter lari/aislamiento & purificación , Portador Sano/epidemiología , Portador Sano/microbiología , Cloaca/microbiología , Femenino , Humanos , Italia , Masculino , Prevalencia
8.
Lett Appl Microbiol ; 46(2): 267-70, 2008 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-18069980

RESUMEN

AIM: To evaluate the presence of thermotolerant Campylobacter spp. in stray cats in southern Italy. METHODS AND RESULTS: One hundred and thirteen animals were trapped in two different environments (urban area, harbour area) of the city of Naples. From each cat, rectal swabs were collected. The samples were processed in order to detect thermotolerant Campylobacter spp. by culture methods. The positive samples were then confirmed by multiplex polymerase chain reaction. Campylobacter jejuni was isolated from 19/113 (16.8%) stray cats, whereas Campylobacter coli was not isolated. The cat data (age, environment and sex) were analysed by two statistical analyses using the C. jejuni status (positive/negative) as a dependent variable. As regards statistical regression model results, age and environment were risk factors for C. jejuni positivity. In particular, cats older than 1 year had a significantly higher risk of being positive for C. jejuni than cats aged up to 1 year (OR = 10.440; P = 0.000). Moreover, cats living in the harbour area had a significantly higher risk to be a carrier of C. jejuni than cats living in urban area (OR = 17.911; P = 0.008). CONCLUSION: The findings of the present survey confirm stray cats as potential carriers of C. jejuni. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first study on the prevalence of C. jejuni in stray cats in Europe.


Asunto(s)
Campylobacter jejuni/aislamiento & purificación , Gatos/microbiología , Animales , Campylobacter jejuni/genética , ADN Bacteriano/análisis , ADN Bacteriano/genética , Italia , Reacción en Cadena de la Polimerasa/métodos , Temperatura
9.
J Neurochem ; 102(4): 1095-104, 2007 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-17472706

RESUMEN

Alzheimer's disease (AD) is characterized by senile plaques and neurodegeneration although the neurotoxic mechanisms have not been completely elucidated. It is clear that both oxidative stress and inflammation play an important role in the illness. The compound curcumin, with a broad spectrum of anti-oxidant, anti-inflammatory, and anti-fibrilogenic activities may represent a promising approach for preventing or treating AD. Curcumin is a small fluorescent compound that binds to amyloid deposits. In the present work we used in vivo multiphoton microscopy (MPM) to demonstrate that curcumin crosses the blood-brain barrier and labels senile plaques and cerebrovascular amyloid angiopathy (CAA) in APPswe/PS1dE9 mice. Moreover, systemic treatment of mice with curcumin for 7 days clears and reduces existing plaques, as monitored with longitudinal imaging, suggesting a potent disaggregation effect. Curcumin also led to a limited, but significant reversal of structural changes in dystrophic dendrites, including abnormal curvature and dystrophy size. Together, these data suggest that curcumin reverses existing amyloid pathology and associated neurotoxicity in a mouse model of AD. This approach could lead to more effective clinical therapies for the prevention of oxidative stress, inflammation and neurotoxicity associated with AD.


Asunto(s)
Enfermedad de Alzheimer , Curcumina/metabolismo , Curcumina/uso terapéutico , Neuritas/efectos de los fármacos , Fármacos Neuroprotectores/metabolismo , Fármacos Neuroprotectores/uso terapéutico , Enfermedad de Alzheimer/metabolismo , Enfermedad de Alzheimer/patología , Enfermedad de Alzheimer/prevención & control , Péptidos beta-Amiloides/metabolismo , Precursor de Proteína beta-Amiloide/genética , Animales , Modelos Animales de Enfermedad , Ensayo de Inmunoadsorción Enzimática , Femenino , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Neuronas/patología , Presenilina-1/genética
10.
Gene ; 275(1): 149-56, 2001 Sep 05.
Artículo en Inglés | MEDLINE | ID: mdl-11574163

RESUMEN

The present paper reports the full nucleotide sequence of a cloned cDNA prepared from RNA of lizard ovaries. The open reading frame consists of 2019 nucleotides, which encodes a protein of 673 amino acids belonging to the G protein-coupled receptor superfamily with a large extracellular N-terminal domain involved in hormone recognition. The transmembrane domain ends with a short intracytoplasmic COOH-terminal domain involved in effector activation. Phylogenetic analysis showed that the lizard receptor belongs to the family of follicle-stimulating hormone (FSH) receptors. The hydrophobicity profile is similar to that observed for mammalian and avian FSH receptors. Northern blot analysis of total RNA revealed that the FSH receptor is expressed at high levels in the ovary. In situ hybridization experiments demonstrate that FSH receptor mRNA is specifically localized within the small cells of the follicular epithelium surrounding the oocyte.


Asunto(s)
Lagartos/genética , Receptores de HFE/genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Northern Blotting , Clonación Molecular , ADN Complementario/química , ADN Complementario/genética , Femenino , Expresión Génica , Hibridación in Situ , Datos de Secuencia Molecular , Ovario/metabolismo , Filogenia , ARN/genética , ARN/metabolismo , Análisis de Secuencia de ADN , Distribución Tisular
11.
Transplantation ; 71(8): 1106-12, 2001 Apr 27.
Artículo en Inglés | MEDLINE | ID: mdl-11374411

RESUMEN

BACKGROUND: Improvements in immunosuppressive therapy have greatly reduced acute rejection (ARj) episodes, ensuring better short-term graft outcome, but have not modified long-term survival in renal transplantation. It is now well accepted that chronic rejection (CRj) can be determined by both immune and/or nonimmune mechanisms. The aim of this study was to evaluate the importance of the posttransplant humoral immune response towards mismatched HLA graft antigens in CRj occurrence and graft outcome. METHODS: Serum samples from 120 nonpresensitized renal transplant recipients were prospectively screened for 1 year after surgery by means of flow cytometry cross-match (FCXM) and FlowPRA beads (microbeads coated with purified HLA class I and class II antigens) assays. All transplants were followed-up for 2 years or until graft removal. RESULTS: FCXM monitoring identified donor-specific antibodies (DS-Abs) in 29 (24.2%) of 120 transplanted patients. Correlation with clinical data highlighted a higher incidence of ARj in DS-Abs-positive patients compared to negative patients (62% vs. 13%, P<0.00001). Furthermore, graft failure occurred more frequently among FCXM-positive patients than among negative patients (34% vs. 1%, P<0.00001). The deleterious effect of DS-Abs on graft function was confirmed by serum creatinine levels 2 years after transplantation. These were in fact higher in subjects producing DS-Abs than in subjects with only ARj (mean creatinine: 2.5+/-1.3 mg/dL vs.1.7+/-0.5 mg/dL, P=0.04). FlowPRA analysis of DS-Ab HLA specificity highlighted the presence of anti-HLA class I antibodies in 85% of FCXM-positive patients, who also presented with a higher incidence of HLA-B mismatches than FCXM-negative patients (1.23+/-0.66 vs. 0.92+/-0.59, P=0.02). CONCLUSIONS: Flow cytometric techniques are precious tools for investigating the activation of the humoral response against HLA antigens of the graft in renal transplantation. DS-Abs production has a worse impact on organ function and survival than ARj episodes. These findings represent further proof of the threat posed by DS-Abs on long-term graft function and draw attention to the need for a specific immunosuppressive therapy aimed at counteracting the different kinds of immune activation toward graft.


Asunto(s)
Rechazo de Injerto/epidemiología , Isoanticuerpos/inmunología , Trasplante de Riñón/inmunología , Adulto , Creatinina/sangre , Femenino , Citometría de Flujo/métodos , Rechazo de Injerto/inmunología , Antígenos HLA-A/inmunología , Antígenos HLA-B/inmunología , Antígenos HLA-DR/inmunología , Prueba de Histocompatibilidad , Humanos , Trasplante de Riñón/fisiología , Masculino , Reoperación , Insuficiencia del Tratamiento , Resultado del Tratamiento
14.
J Biol Chem ; 276(17): 14161-9, 2001 Apr 27.
Artículo en Inglés | MEDLINE | ID: mdl-11278317

RESUMEN

The INK4a gene, one of the most often disrupted loci in human cancer, encodes two unrelated proteins, p16(INK4a) and p14(ARF) (ARF) both capable of inducing cell cycle arrest. Although it has been clearly demonstrated that ARF inhibits cell cycle via p53 stabilization, very little is known about the involvement of ARF in other cell cycle regulatory pathways, as well as on the mechanisms responsible for activating ARF following oncoproliferative stimuli. In search of factors that might associate with ARF to control its activity or its specificity, we performed a yeast two-hybrid screen. We report here that the human homologue of spinophilin/neurabin II, a regulatory subunit of protein phosphatase 1 catalytic subunit specifically interacts with ARF, both in yeast and in mammalian cells. We also show that ectopic expression of spinophilin/neurabin II inhibits the formation of G418-resistant colonies when transfected into human and mouse cell lines, regardless of p53 and ARF status. Moreover, spinophilin/ARF coexpression in Saos-2 cells, where ARF ectopic expression is ineffective, somehow results in a synergic effect. These data demonstrate a role for spinophilin in cell growth and suggest that ARF and spinophilin could act in partially overlapping pathways.


Asunto(s)
Proteínas de Microfilamentos/química , Proteínas del Tejido Nervioso/química , Proteínas/química , Proteínas/metabolismo , Células 3T3 , Secuencia de Aminoácidos , Animales , Western Blotting , Células COS , Catálisis , Dominio Catalítico , División Celular , Células Cultivadas , Exones , Eliminación de Gen , Genes p53/genética , Glutatión Transferasa/metabolismo , Humanos , Ratones , Proteínas de Microfilamentos/metabolismo , Datos de Secuencia Molecular , Proteínas del Tejido Nervioso/metabolismo , Fosfoproteínas Fosfatasas/química , Pruebas de Precipitina , Unión Proteica , Proteína Fosfatasa 1 , Estructura Terciaria de Proteína , Proteínas/genética , ARN Mensajero/metabolismo , Ratas , Homología de Secuencia de Aminoácido , Transfección , Células Tumorales Cultivadas , Proteína p14ARF Supresora de Tumor , Técnicas del Sistema de Dos Híbridos
15.
Transpl Int ; 13 Suppl 1: S439-43, 2000.
Artículo en Inglés | MEDLINE | ID: mdl-11112049

RESUMEN

This study was designed to investigate the clinical relevance of donor-specific antibodies (DS-Abs) and their influence on graft survival. Among 106 patients who underwent cadaveric kidney donor transplantation and were monitored by flow cytometry crossmatch (FCXM) during the 1st posttransplantation year, 25 (23.6%) resulted positive for DS-Ab production. During a 2-year follow up only 12 of the 81 FCXM-negative patients (14.8%) suffered rejection vs 17 of 25 FCXM-positive patients (68%; P = 0.00001). Correlating graft loss to DS-Ab production, 9 FCXM-positive patients lost the graft vs only 1 among the FCXM-negative patients. A worse graft function was evidenced in FCXM-positive subjects who had also suffered rejection episodes than in those which had acute rejection but did not produce DS-Abs. A high incidence of HLA-AB mismatches was found in FCXM-positive subjects which produced anti-class I antibodies. FCXM appears useful in estimating posttransplant alloimmune response. Moreover our findings confirm the harmful effects of anti-class I DS-Abs on long-term graft survival.


Asunto(s)
Supervivencia de Injerto/inmunología , Isoanticuerpos/inmunología , Trasplante de Riñón/inmunología , Formación de Anticuerpos , Cadáver , Creatinina/sangre , Citometría de Flujo , Estudios de Seguimiento , Prueba de Histocompatibilidad , Humanos , Inmunoglobulina G/sangre , Trasplante de Riñón/fisiología , Linfocitos/inmunología , Estudios Retrospectivos , Bazo/inmunología , Donantes de Tejidos
16.
J Endocrinol ; 167(2): 275-80, 2000 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-11054641

RESUMEN

The study of environmental factors affecting vertebrate reproduction has long interested both developmental and evolutionary biologists. Although photoperiod has been considered to be an important environmental parameter for vertebrates such as birds, temperature is probably a primary external factor responsible for reproductive cyclicity in reptiles. In spite of the progress made in the understanding of reptilian reproductive strategies and adaptations, much remains to be learned about the interplay between endocrine physiological factors, such as hormones, and environmental parameters. In this report, we have examined the effects of in vivo administered FSH on oocyte recruitment during the most significant periods of the reproductive cycle of the lizard, Podarcis sicula. The results show that when FSH is administered in proximity to the reproductive period, it stimulates oocyte growth and ovulation; when the hormone is administered at the beginning of the winter stasis it affects ovarian activity without inducing ovulation. Ovarian adenylate cyclase activity is moderately sensitive to in vitro FSH stimulation during the pre- and post-reproductive periods. The sensitivity to hormone stimulation increases significantly during the reproductive period and winter stasis. We have also tested the hypothesis that environmental temperature affects the responsiveness of ovarian adenylate cyclase to FSH stimulation. For such a purpose, we exposed animals to 28 degrees C or 4 degrees C in different periods of the ovarian cycle. The results show that, whenever the temperature applied mimics the thermal regime of the coming season, adenylate cyclase sensitivity to FSH shifts towards levels that anticipate the natural responsiveness.


Asunto(s)
Adenilil Ciclasas/metabolismo , Lagartos/fisiología , Ovario/enzimología , Estaciones del Año , Temperatura , Análisis de Varianza , Animales , Femenino , Hormona Folículo Estimulante/farmacología , Lagartos/metabolismo , Oocitos/efectos de los fármacos , Oocitos/crecimiento & desarrollo , Ovario/efectos de los fármacos , Reproducción/fisiología
18.
Mol Reprod Dev ; 52(2): 126-34, 1999 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-9890742

RESUMEN

During vitellogenesis, the oocytes of oviparous species accumulate in the cytoplasm a large amount of proteic nutrients synthetized in the liver. Once incorporated into the oocytes, these nutrients, especially represented by vitellogenin (VTG) and very low-density lipoprotein (VLDL), are cleaved into a characteristic set of polypeptides forming yolk platelets. We have studied the molecular mechanisms involved in yolk formation in a reptilian species Podarcis sicula, a lizard characterized by a seasonal reproductive cycle. Our results demonstrate the existence in the lizard ovary of an aspartic proteinase having a maximal activity at acidic pH and a molecular mass of 40 kDa. The full-length aspartic proteinase cDNA produced from total RNA by RT-PCR is 1,442 base pairs long and encodes a protein of 403 amino acids. A comparison of the proteic sequence with aspartic proteinases from various sources demonstrates that the lizard enzyme is a cathepsin D. Lizard ovarian cathepsin D activity is maximal in June, in coincidence with vitellogenesis and ovulation, and is especially abundant in vitellogenic follicles and in eggs. Ovarian cathepsin D activity can be enhanced during the resting period by treatment with FSH in vivo. Northern blot analysis shows that cathepsin D mRNA is exceedingly abundant during the reproductive period, and accumulates preferentially in previtellogenic oocytes.


Asunto(s)
Catepsina D/genética , Lagartos , Ovario/enzimología , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Catepsina D/aislamiento & purificación , Catepsina D/metabolismo , Clonación Molecular , ADN Complementario , Femenino , Expresión Génica , Gónadas , Humanos , Datos de Secuencia Molecular , ARN Mensajero , Reproducción , Homología de Secuencia de Aminoácido
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA