Cooling stored epididymal samples for several days allows facilities to transport and process genetic material post‐mortem. Improvements to this practice allow the preservation of sperm from domestic cats, which are the ideal study model for wild felids. However, the modifications in spermatic features and the oxidative profile are not fully understood in cats. This information is necessary for the development of biotechniques, such as new extenders for cryopreservation. Therefore, the purpose of this study was to evaluate the spermatic and oxidative profile in samples from the epididymal cauda of domestic cats cooled at 5°C for 24, 48 and 72 hr. Spermatozoa were collected from the epididymis cauda. Evaluations consisted of computer‐assisted sperm analysis (CASA), plasma membrane integrity (eosin/nigrosin), acrosome integrity (fast green/rose bengal), sperm morphology, sperm DNA integrity (toluidine blue), mitochondrial activity (3′3 diaminobenzidine), activity of the antioxidant enzymes glutathione peroxidase (GPx) and superoxide dismutase (SOD), measurement of lipid peroxidation (TBARS) and protein oxidation. A decrease in sperm motility parameters was observed after 72 hr of cooling (i.e. total and progressive) with a higher percentage of minor (37.7 ± 6.3%) and total defects (53.4 ± 6.3%). Additionally, a decrease in high mitochondrial activity (Class I: 16.6 ± 2.2%) occurred after 72 hr. The decrease in motility rates after a long cooling time probably was caused by the increase in sperm abnormalities. A long cooling time causes cold shock and mitochondrial exhaustion, but there was no observed change with the oxidative stress condition. Therefore, cat epididymal sperm stored at 5°C appear to maintain a high quality for up to 48 hr of cooling time. 相似文献
Sperm DNA fragmentation is a condition that interferes directly in the reproductive efficiency. Currently, there are several methods for assessing the sperm DNA integrity, such as Alkaline Comet, TUNEL and Sperm Chromatin Structure Assay. However, many of these techniques are laborious and require high‐precision equipment. Thus, the development of new techniques can optimize the evaluation of sperm DNA damage. Therefore, the aim of this study was to standardize the toluidine blue (TB) stain technique for the analysis of DNA fragmentation of dog, cat, bull, stallion and ram spermatozoa. For this purpose, we used six animals of each specie (n = 30), in reproductive age. Sperm was collected by different methods according to the particularities of each species, and such samples were divided into two aliquots: a sperm sample was kept at 5°C (considered as intact sperm DNA), and the remaining samples were submitted to the induction of DNA fragmentation by exposure to ultraviolet light for 4 hr. Samples were then mixed with the intact sample to obtain known and progressive proportions of sperm with fragmented DNA (0%, 25%, 50%, 75% and 100%). Semen smears were performed and subjected to staining with TB. Blue‐stained spermatozoa were considered to have DNA fragmentation. We observed high linear regression coefficients between the expected proportion of damaged DNA and the results of TB for dog, cat, ram, bull and stallion samples. In conclusion, TB stain was considered a fast and effective technique for the study of spermatozoa DNA in several species. 相似文献
The development of the parotid gland was examined in 36 bovine embryos and foetuses with a crown-rump-length (CRL) from 28 up to 1000 mm by light, transmission electron microscopical and actin-immunohistochemical methods. The anlage of the parotid gland in an embryo with 28 mm CRL can be found at the lateral angle of the primitive oral cavity as a local thickening of the epithelium. During the second month, the differentiation of primary ducts and endbuds starts and a lumen develops in the primary ducts. At the end of the second month a lumen appears in the terminal endbuds. In the immature endpiece cells first secretory granules can be seen from a CRL of 240 mm. In the third month differentiation between intra- and inter-lobular ducts is possible. Immature myoepithelial cells present as a basal layer of flattened cells between the epithelial cells and the basement membrane at the end of the second month. During further development they increase in number, become more flattened and form long cellular processes. At the end of the fourth month isolated actin filament bundles are formed, which were also detected by an antibody against smooth muscle actin. The actin filaments condense continuously until they fill the cell processes completely at the end of foetal development. 相似文献
Epidemics of Peronospora parasitica are strongly affected by temperature and air moisture, and the interaction of these factors. Because a significant percentage
of radish plants are grown in greenhouses, it may be possible to influence epidemics by altering the greenhouse climate. The
objective of this study was to test the hypothesis that epidemics of P. parasitica can be modelled by the effects of air temperature and moisture in the greenhouse. Such a model could then be used to analyse
greenhouse climate control strategies with regard to managing downy mildew. Five radish crops were grown under greenhouse
conditions with set-points for heating and ventilation intended to obtain favourable conditions for disease development during
the first part of the growing cycle. Subsequent to this first phase, unfavourable conditions were set until harvest. Disease
incidence was measured once a week until the radishes reached marketable size. In addition, experiments were carried out in
growth chambers in which inoculated plants were subjected to air temperatures between 8 and 27°C, and disease incidence and
sporulation intensity were measured. Data from these two experiments were then used to estimate model parameters. In this
model, the interactions of air temperature (T) and water vapour saturation deficit (SD) were adequately described by a multiplicative
relationship. The simulated epidemics by the fitted model were highly correlated with the observed epidemics (r = 0.91, R2 = 0.83, n = 29). Parameter estimates indicated that T of ca. 20°C and SD < 0.03 hPa resulted in the highest rates of disease development
and that the rate was zero when SD > 2.0 hPa. Both experimental data and simulations showed that epidemics of P. parasitica can be effectively controlled by managing the greenhouse climate. 相似文献
Since the mid-1970's new types of forest damage (of unknown origin) were observed in West Germany. Nonspecific foliage losses and foliar discolorations are the most common symptoms. This resulted in a comprehensive research program being initiated in the fall of 1983 to investigate the nutritional status of Norway spruce (Picea abies (L.) Karst.) stands in southwest Germany, growing on a variety of sites. Forests at these sites revealed light to moderate damage or acute site-and species-specific nutritional disturbances involving Mg, K, Ca, Mn, and Zn. Historical comparisons of needle-analysis data showed a dramatic change of the nutrient supply at many sites over the last one or two decades.
As a working hypothesis, the adverse impacts of air pollutants (e.g. photo-oxidants) and/or acidic atmospheric precipitation are seen as inciting factors causing increased leaching of nutrient elements. The tree's potential to compensate for the nutrient losses by increased uptake are limited by the often poor nutrient supply for forest soils. Accelerated soil acidification increase nutrient leaching from the soil, probably enhancing decline. Over a short period, fertilization led to a decrease or to the disappearance of the symptoms, and to the improvement in the nutrient composition of the foliage.
Microscopy investigation of Norway-spruce needles indicated the regeneration potential on a histological level for moderate yellowed needles after fertilization. Furthermore, needles of nutrient-deficient-trees reveal typical tissue damages different to those caused by SO2 or O3.
Acid mist increased the leaching of K, Ca, Mg, Mn, and Zn from the foliage. Even when nutrients are being leached from the foliage, nutrient uptake canbe increased by improving the nutrient supply in the soil.
Preliminary studies on the effects of damages caused by ozone (O3) on ponderosa pine suggest imbalance in micronutrient concentrations of foliage. 相似文献
ObjectiveTo determine the agreement of high definition oscillometry (HDO) with direct arterial blood pressure measurements in normotensive, hypotensive and hypertensive horses during general anaesthesia.Study designExperimental study.AnimalsSeven healthy warmblood horses, aged 3–11 years, weighing 470–565 kg.MethodsMeasurements from a HDO device with the cuff placed around the base of the tail were compared with pressures measured invasively from the facial artery. High blood pressures were induced by intravenous (IV) administration of dobutamine (5 μg kg−1 minute−1) over ten minutes followed by norepinephrine (0.1 mg kg−1 IV) and low pressures by increasing the inspired fraction of isoflurane and administration of nitroglycerine (0.05 mg kg−1 IV). For analysis three pressure levels were determined: high (MAP>110 mmHg), normal (60 mmHg