Effects of Retinoids on the In Vitro Development of Capra Hircus Embryos to Blastocysts in Two Different Culture Systems

The objective of this study was to evaluate the effect of retinol (RT) and retinoic acid (RA) on the in vitro development of pre‐implantation goat embryos cultured in potassium simplex optimized medium or synthetic oviduct fluid or cocultured in oviductal cells monolayer either in potassium simplex optimized medium or synthetic oviduct fluid. A total of 2407 cumulus‐oocyte complexes were aspirated from 2 to 6 mm ovarian follicles from slaughtered animals. Selected cumulus‐oocyte complexes were subjected to in vitro maturation in TCM 199 for 24 h at 39°C in an atmosphere of 5% (v/v) CO₂ in humidified air. In vitro fertilization was performed in modified defined medium. Eighteen hours after in vitro fertilization, cumulus cells were removed and presumptive zygotes were randomly distributed into experimental groups. In Experiment 1, presumptive zygotes were cultured in potassium simplex optimized medium, potassium simplex optimized medium + RT, potassium simplex optimized medium + retinoic acid, synthetic oviduct fluid, synthetic oviduct fluid + RT and synthetic oviduct fluid + RA at 39°C in a humidified atmosphere of 5% (v/v) CO₂, 5% (v/v) O₂ and 90% (v/v) N₂. In Experiment 2, presumptive zygotes were cocultured in potassium simplex optimized medium + oviductal cells monolayer, potassium simplex optimized medium + RT + oviductal cells monolayer, potassium simplex optimized medium + RA + oviductal cells monolayer, synthetic oviduct fluid + oviductal cells monolayer, synthetic oviduct fluid + RT + oviductal cells monolayer and synthetic oviduct fluid + RA + oviductal cells monolayer in an atmosphere of 5% (v/v) CO₂ in humidified air. In both experiments, media were partially changed on day 2 after in vitro fertilization and unfertilized oocytes were excluded from the experiment. Embryos were cultured or cocultured for 8 days. In Experiment 1, there was no effect of RT or RA supplementation on the proportion of oocytes that reached the morula or blastocyst stages. By contrast, Experiment 2 demonstrated that the addition of 0.28 μg/ml RT and 0.5 μm RA to the embryo culture media stimulated (p < 0.05) development to the morula and blastocyst stages under the coculture conditions tested. In conclusion, retinoids play an important role in pre‐implantation development of goat embryos and can be used to enhance in vitro embryo production.     

Reduction in channel catfish hepatic growth hormone receptor expression in response to food deprivation and exogenous cortisol

The objective of this study was to assess the effects of food deprivation and exogenous cortisol administration on somatic growth of channel catfish, Ictalurus punctatus, and examine the resultant changes in circulating insulin-like growth factor-I (IGF-I) concentrations and growth hormone receptor (GHR) gene expression. Integral to this objective, we report the isolation, sequence, and characterization of channel catfish GHR. Sequence analysis and characterization results indicate sequence identity and tissue distribution similar to GHRs in other teleost fish and several functional characteristics conserved in known vertebrate GHRs. The effects of food deprivation and dietary exogenous cortisol administration were assessed as part of a 4-week study. Growth was significantly reduced after 4 weeks in cortisol-fed fish compared to fed-control fish, and fasting resulted in weight loss. At the end of the 4-week study, both IGF-I plasma concentrations and hepatic GHR mRNA abundance were significantly reduced in fasted and cortisol-fed catfish. Levels of hepatic GHR mRNA were positively correlated to circulating IGF-I levels. These results suggest that a reduction in hepatic GHR gene expression might serve as a mechanism for the reduction of circulating IGF-I and growth in channel catfish during periods of food deprivation and stress.     

Mercury: the dark-side temperature

The planet Mercury was observed before, during, and after the inferior conjunctions of 29 September 1969 and 9 May 1970 at wavelengths of 3.75, 4.75, 8.6, and 12 microns. The average dark-side temperature is 111 degrees +/- 3 degrees K. The thermal inertia of the surface required to fit this temperature is close to that for the moon and indicates that Mercury and the moon have very similar top surface layers.     

Treatment with eCG Decreases the Vascular Density and Increases the Glandular Density of the Bovine Uterus

The uterus plays an essential role in mammalian reproduction and is a target of several hormonal protocols used to improve fertility in cattle. Many studies highlighted the importance of eCG treatment following fixed‐time artificial insemination in improving follicular growth, ovulation and pregnancy rates in cattle. Moreover, eCG has been implicated in angiogenesis, leading to important changes in uterine blood flow and vascularisation. However, there is still a lack of information regarding the specific alterations induced by eCG upon glandular and vascular characteristics of bovine uterus. To investigate the influence of eCG on: uterine thickness and area; uterine artery diameter and area; uterine vascular and gland density; and the expression of the VEGFA‐system, the uteri of crossbred beef cows were collected. All cows were submitted to follicular wave emergence synchronization. On day four of protocol, cows submitted to superovulation (n = 6) received 2000 IU eCG, on day eight, after expected follicular deviation, cows submitted to stimulatory treatment (n = 5) received 400 IU eCG. Control cows (n = 5) did not receive eCG. On day five po cows were subjected to ultrassonographic evaluation and slaughtered for uterine tissue sampling on day six po. Uterine vessels and glands were quantified by the counting point stereological method. The VEGFA‐system was localized in different cellular types, showing no qualitative or quantitative differences in the site of expression or the intensity of the positive signal among the groups. Vascular density was decreased in the endometrium of stimulated and myometrium of superovulated cows compared with the control ones, which showed higher vascular density in the myometrium and endometrium of the ipsilateral uterine horn. The uterine gland density was higher in superovulated compared with stimulated and control cows. Thus, we can infer that stimulatory or superovulatory treatments with eCG influence the vascular density in the endometrium and myometrium in cattle.     

The dynamics of vegetation contamination by radionuclides on a tide washed pasture in the Mersey Estuary

Measurements of ¹³⁷Cs, ^239/240Pu and ²⁴¹Am contamination in substrate and vegetation on a tide washed pasture in the Mersey Estuary have enabled the dynamic response of vegetation contamination resulting from individual inundation events to be observed. Vegetation contamination is almost entirely due to external contamination by sediment, although there is some evidence for a small contribution from root uptake for ¹³⁷Cs, with a transfer factor from substrate to internal plant of about 0.003. Marked temporal variation is consistent with contamination by deposition of suspended sediments during tidal inundations, subsequently decreasing with a halflife of 20–30 days. Overall accumulation factors (total plant:substrate) are lower than those observed for the few pastures and saltmarshes studies further north in Cumbria, and consistent with the lower inundation frequency of the Mersey Estuary site.     

Eucalypt plantation management in regions with water stress

Most eucalypt plantations are managed in short rotations (6–8 years) and are established in regions with water and nutritional stresses of varying degrees. The mean annual increment in these regions ranges from 20 to 45 m³ ha^?1 y^?1 depending on the level of environmental stress. Improving natural resource use efficiency by breeding and matching genotypes to sites and using appropriate site management practices is a key challenge to sustain or increase productivity. Climate change is emerging as a driving force behind many of the current issues facing natural resources, and is likely to intensify the water constraint. The Intergovernmental Panel on Climate Change has predicted significant increases in surface air temperatures and decreases in rainfall (with more erratic rainfall patterns) over the tropics and subtropics, affecting drier regions in particular. To be truly sustainable, forest management practices must be environmentally friendly, prevent or reduce land degradation, improve biodiversity and increase resilience to climate variation and change. The main efforts should address the problems of water scarcity, low soil fertility and reduced biodiversity. Forest growers should take into account the inherent risks of different forest management systems on the regional water availability and consider reducing forest productivity in order to maintain both ecological and social equilibrium. The design and implementation of management techniques should be adapted to the specific production and protection objectives, which depend on the regional and local edaphoclimatic circumstances, water resources management, protection against soil erosion, diseases, pests, bushfires, strong winds and alien species. This paper addresses the basic requirements for integrating genetic and silvicultural strategies to minimise the water constraints in eucalypt plantations and surrounding water and native vegetation resources. We show several examples of effective forest management actions on the scale of forest stand and watershed in use in Brazil.     

Rare and endangered plants and animals of southern Appalachian wetlands

At least one-third of the threatened and endangered species of the United States live in wetlands. Southern Appalachian bogs and fens, in particular, support a wealth of rare and unique life forms, many of which are found in no other habitat type. In North Carolina alone, nonalluvial mountain wetlands provide habitat for nearly 90 species of plants and animals that are considered rare, threatened, or endangered by the North Carolina Plant Conservation Program, the North Carolina Natural Heritage Program, the North Carolina Wildlife Resources Commission, or the U.S. Fish and Wildlife Service. These species include the bog turtle, mountain sweet pitcher plant, green pitcher plant, swamp pink, bunched arrowhead, and Gray's lily, all of which are either on the federal list of endangered and threatened species or under consideration for that list. Mountain wetland habitats for these species are being destroyed and degraded at an accelerating rate for highway construction and expansion and residential and recreational development, as well as for industrial and agricultural uses.     

Repeat Ovum Pick-up and In Vitro Embryo Production from Adult Ewes with and without FSH Treatment

Ovum pick-up (OPU) was performed three times on adult ewes after synchronization with (n = 4) or without (n = 4) FSH treatment to investigate the effects of FSH treatment on the number of ovarian follicles, oocytes recovered, oocyte quality and development in vitro. FSH treatment increased the number of ovarian follicles (85 vs 162) and oocytes recovered (33 vs 91), although recovery rate was similar for ewes with and without FSH (91/162, 56.2% and 33/85, 38.8% respectively). Of the oocytes recovered, those classified as grades I and II were similar between ewes with (78/91, 85.7%) and without FSH treatment (27/33, 81.8%). The number of ovarian follicles was similar after repeated OPU for ewes treated with FSH, but for ewes not treated with FSH the number of ovarian follicles decreased with repeated OPU. The number of oocytes recovered decreased for FSH-treated ewes only, while the oocyte recovery rate and proportion of oocytes classified as grades I and II were not affected by repeated OPU. Oocyte cleavage (46/78, 58.9% and 19/24, 79.2%) and blastocyst formation (35/46, 76.1% and 12/19, 63.2% respectively) were similar for ewes with and without FSH treatment. The number of ovarian follicles varied between ewes (p < 0.05) although the number of oocytes recovered and oocyte development in vitro were similar between ewes.     

Using 20-gauge percutaneous peripheral catheters to reliably collect serial 4-mL blood samples from conscious dogs

Objective To determine the reliability of collecting serial 4-mL blood samples over 13 h using a 20-gauge, cephalic catheter in conscious dogs. Design Prospective, observational study. Animals Twelve (6 males, 6 females) healthy, neutered, lean dogs. Procedure Percutaneous placement of a 20-gauge, 1.1 × 30 mm intravenous over-the-needle catheter into the cephalic vein was performed in each dog on three occasions. Catheter patency was maintained by intermittent flushing with 0.9% saline and 1 IU/mL heparinised saline solutions. Blood samples (4 mL) were obtained at 10 time-points over 13 h, with close monitoring of the dogs and the indwelling catheters. Blood volume, resistance on aspirating blood sample (minimal or marked resistance) and the methods used to improve blood flow were recorded. Results A high proportion (93%) of blood sample collections achieved the required 4-mL volume, and the remaining samples were greater than 1.5 mL. Of the 358 collections via the cephalic catheter, 311 (87%) were obtained with ‘minimal resistance’. The remaining collections had ‘marked resistance’ (n=47) and were associated with a loose catheter in 11% (5/47) and of unknown cause in 89% (42/47). After ‘marked resistance’ had been encountered and the catheter was flushed with saline and heparin solutions, subsequent sampling with ‘minimal resistance’ was frequently possible from the same catheter. Conclusion Use of a percutaneous, 20-gauge intravenous cephalic catheter allowed reliable serial collection of 4-mL blood samples over 13 h in conscious dogs.