Radiation-induced low-temperature tolerant solid mutants of Chrysanthemum morifolium Ram.

Summary From irradiated explants of the chrysanthemum cultivar Parliament solid non-chimeric low-temperature tolerant mutants were obtained. Some of the mutants flowered approx. 2 weeks earlier than control plants at a temperature of 12°C D/N and looked otherwise identical to the original genotype. The significance of it is discussed, a.o. in relation to attempts in developing selection methods at cell level for such characteristics.     

Computer simulation of the structure and dynamics of phenol in sodium montmorillonite hydrates

Monte Carlo and molecular dynamics computer simulations have been used to study the structure and dynamics of phenol‐water solutions in the bulk and confined within the interlayer pores of sodium montmorillonite clays, as a function of pressure and temperature. Conditions have been chosen to mimic those encountered at burial depths of up to 6 km, thereby enabling us to shed light on subsurface processes including groundwater contamination and oil and gas migration. The structural data show that the phenol molecules are able to form a donor hydrogen bond to the clay surface. In addition, the phenolic –OH group is solvated by approximately three water molecules, and is also able to coordinate directly to an interlayer sodium cation. The phenolic aromatic ring is surrounded by approximately 25 water molecules in the bulk, compared to 18 in the compacted clay. Interlayer diffusion increases by an order of magnitude as temperature is increased from 275 K to 460 K. However, diffusion decreases by a factor of 2–4 as we move from the bulk into a clay hydrate of layer spacing ∼17 Å. For example, at 275 K the diffusion coefficient of phenol is 8.3 × 10⁻¹⁰ m² s⁻¹ in bulk solution, compared to 2.5 × 10⁻¹⁰ m² s⁻¹ in the clay.     

Increased dietary phosphorous prevents vertebral deformities in triploid Atlantic salmon (Salmo salar L.)

Triplicate groups of triploid and diploid Atlantic salmon were fed diets with a low (LP, total P: 7.1 g kg^?1), medium (MP, total P: 9.4 g kg^?1) or high (HP, total P: 16.3 g kg^?1) phosphorous (P) level from first feeding (0.18 g) to transfer to sea water (~50 g, duration: 203 days) and subsequently fed a commercial diet in sea water for 426 days (~3 kg). This study examined the short‐ and long‐term effects of dietary P on freshwater performance (mortality, growth), vertebral deformities (radiology), bone cell activity (ALP and TRACP enzyme activity in vertebrae and scales, and fgf23, bgp and igf‐I relative gene expression in vertebrae), bone mineralization (ash content) and some parameters related to fish condition (heart and liver size). Irrespective of ploidy, at seawater transfer, fish fed the MP diet had significantly highest length and weight and those fed the LP diet significantly lowest length and weight, while those fed the HP diet had intermediate lengths and weights. Increased dietary phosphorus reduced deformities in both ploidies at seawater transfer; however, triploids fed the LP and MP diets had more deformities than diploids fed the respective diets, while there was no ploidy effect observed for fish fed the HP diet. The vertebral bone ash content at seawater transfer was significantly higher in diploids than in triploids when fed the MP diet only. Alkaline phosphatase (ALP) and tartrate‐resistant acid phosphatase (TRACP) enzyme activities and relative gene expression of bone hormones involved in metabolism of plasma phosphate (fgf23) and bone growth (bgp) were not affected by ploidy at seawater transfer, but by dietary P level; LP increased ALP activity and reduced TRACP activity and fgf23 and bgp expression levels in vertebral bone. In scales, LP increased both ALP and TRACP activity. At the termination of the seawater period, the group‐wise pattern in occurrence of vertebral deformities was the same as at seawater transfer. The present results on mortality, growth, bone mineralization and development of skeletal deformities all demonstrate that triploids have a higher P requirement than diploids in fresh water. This study shows that an optimalization of P nutrition for triploid Atlantic salmon can improve health and welfare and reduce down‐grading of triploid salmon.     

An epizootic of chronic regurgitation associated with chlamydophilosis in recently imported emerald tree boas (Corallus caninus).

One hundred and five wild-caught emerald tree boas (Corallus caninus) were added to a collection of 15 others. in Central Florida, during a 4-mo period. Eighty-one boas (67%) developed repetitive regurgitation during the 23-mo period after the initial introduction, and 61 (75%) of these died. Regurgitation occurred 3-4 days after feeding. Prevalence of regurgitation in this population of snakes was 25%/mo (range 0-42%), and incidence was 3.52/mo (range 0-13/mo). The cumulative mortality for those boas developing repetitive regurgitation (61 of 120) during the 23-mo epizootic was 51%. Hematologic findings included anemia and leukocytosis, with lymphocytosis, monocytosis, and azurophilia. Histologic evaluation of the gastrointestinal tract showed multifocal to diffuse lymphoplasmacytic inflammation with granuloma formation and positive immunohistochemical staining for chlamydial antigen. Electron microscopic evaluation of granulomas showed organisms consistent with Chlamydophila sp.     

Total and partial ovariohysterectomy in seven mares

REASONS FOR PERFORMING STUDY: Ovariohysterectomy appears to have a low mortality rate in mares, but the procedure needs to be reviewed because of the high risk of life-threatening complications. HYPOTHESIS: That ovariohysterectomy can be effective treatment for a variety of uterine diseases in mares and carries a good prognosis. METHODS: Diagnosis, clinical data, surgical technique, post operative care, complications and outcome were recorded from medical records of 7 mares that underwent total (6) and partial (1) ovariohysterectomy at the University of Illinois from 1994 to 2001. RESULTS: The indications for ovariohysterectomy were chronic pyometra (4 mares), chronic uterine torsion (n = 2) and chronic intramural haematoma (n = 1). Surgical exposure was difficult but was improved by traction on stay sutures and right-angled clamps. In some cases, application of the TA-90 autosuture instrument as a right-angled clamp to the caudal part of the uterus improved access to the uterine stump. The most common post operative complications were decreased faecal output, decreased intestinal sounds (4 mares) and mild abdominal pain (2). Two mares had mild to moderate incisional infections. Other previously reported complications, such as haemorrhage, septic peritonitis, uterine stump infection or necrosis, and diarrhoea, did not occur. All mares survived over follow-up periods of 6 months to 5 years and were used for riding (6 mares) and embryo transfer (1 mare, after partial ovariohysterectomy). CONCLUSIONS AND POTENTIAL RELEVANCE: According to this study, the prognosis for mares after ovariohysterectomy appears to be good, despite the technical difficulties of the procedure. The prevalence of life-threatening complications can be lower than reported.     

夏玉米复合肥衣种子试验简报

肥衣种子是机械化高产栽培中的一项技术改革,它不仅能广泛应用于精量点播中而且对大面积的森林、草原航空播种也应适用。就精量播种来说,既节省种子用量,又可以获得壮     

Transformation of a tundra river from heterotrophy to autotrophy by addition of phosphorus

Continuous enrichment of an arctic river with only 10 parts per billion phosphate-phosphorus caused an immediate growth of attached algae for more than 10 kilometers downstream, showing that phosphorus alone limited photosynthesis. As a result of the increased photosynthesis, there was an increase in bacterial activity in films on rocks on the bottom of the stream. The major source of energy became the photosynthetic carbon fixed in the stream rather than the organic material entering from the surrounding tundra, and the overall metabolism of the stream shifted from heterotrophy to autotrophy. An increase in the size and developmental stage of some of the dominant aquatic insects illustrates the food limitation in this nutrient-poor habitat.