Genetic Variations in Populations from Farms and Natural Habitats of Asian Green Mussel,Perna viridis,in Singapore Inferred from Nine Microsatellite Markers     

Grace Lin  Loong Chueng Lo  Gen Hua Yue 《Journal of the World Aquaculture Society》2012,43(2):270-277

The Asian green mussel, Perna viridis, has been widely cultured in Southeast Asia as delicious seafood depending on natural spat. We analyzed the genetic diversity and population structure of three populations (two from Singapore and one from Malaysia) from natural habitats and two from Singapore farms, by genotyping a total of 262 adult individuals using nine polymorphic microsatellites. In all five populations, high allelic (number of alleles A = 11.0–14.4,allelic richness Ar = 10.4–13.9) and gene diversity (expected heterozygosity He = 0.73–0.77) were observed, whereas deficiency of heterozygosity (inbreeding index f = 0.08–0.12) was detected in all populations. Genetic differentiation among populations was low (pairwise fixation index ranged from 0.003 to 0.088), but statistically significant. The usefulness of the information about genetic variations for genetic resource management of the populations in wild habitats and farms to keep genetic variation and setting up a breeding program of Asian green mussel was discussed.  相似文献   

Rickets in alpacas (Lama paces) in New Zealand     

F.I. Hill  K.G. Thompson  N.D. Grace 《New Zealand veterinary journal》2013,61(6):229-232

Rickets was diagnosed in two weaner alpacas from a flock showing ill thrift and lameness during the winter of 1992. Both animals had abnormally shaped ribs with occasional healing fractures, irregular thickening of growth plates and metaphyseal haemorrhages. The mean serum phosphorus concentrations of the alpacas fell during June and July, even though lambs grazing the same pasture had normal serum phosphorus concentrations and the phosphorus concentration of the pasture was considered adequate. Vitamin D deficiency may also have contributed to the osteodystrophy. The alpacas had a thick fleece during the winter, and diurnal Vitamin D₃, synthesis resulting from solar irradiation is likely to have been minimal, especially considering the reduced sunshine hours recorded during the 1992 winter. Surviving alpacas recovered after treatment with monosodium phosphate and an oral Vitamin D supplement. It is possible alpacas are more susceptible to deficiencies of phosphorus and Vitamin D than other grazing animals in New Zealand.  相似文献   

Climate influences the leaf area/sapwood area ratio in Scots pine     

Mencuccini M  Grace J 《Tree physiology》1995,15(1):1-10

We tested the hypothesis that the leaf area/sapwood area ratio in Scots pine (Pinus sylvestris L.) is influenced by site differences in water vapor pressure deficit of the air (D). Two stands of the same provenance were selected, one in western Scotland and one in eastern England, so that effects resulting from age, genetic variability, density and fertility were minimized. Compared with the Scots pine trees at the cooler and wetter site in Scotland, the trees at the warmer and drier site in England produced less leaf area per unit of conducting sapwood area both at a stem height of 1.3 m and at the base of the live crown, whereas stem permeability was similar at both sites. Also, trees at the drier site had less leaf area per unit branch cross-sectional area at the branch base than trees at the wetter site. For each site, the average values for leaf area, sapwood area and permeability were used, together with values of transpiration rates at different D, to calculate average stem water potential gradients. Changes in the leaf area/sapwood area ratio acted to maintain a similar water potential gradient in the stems of trees at both sites despite climatic differences between the sites.  相似文献   

Magnetic resonance imaging used for the evaluation of water presence in wood plastic composite boards exposed to exterior conditions     

Marek Gnatowski  Rebecca Ibach  Mathew Leung  Grace Sun 《Wood material science & engineering》2015,10(1):94-111

Abstract

Two wood plastic composite (WPC) boards, one experimental and one commercial, were exposed to exterior conditions and evaluated non-destructively using a clinical magnetic resonance imaging (MRI) unit for moisture content (MC) and distribution. The experimental board was exposed in Vancouver, British Columbia, for more than 8 years, and the commercial board was exposed near Hilo, Hawaii, for 2 years. Both boards were characterized in terms of wood content, density, water uptake properties and voids content. The experimental board was additionally destructively analysed for water absorption of the WPC and MC calculated based on the wood content for verification of MRI results. MRI detected the presence of free water and its distribution in both of the WPC boards. Fibre saturation in the experimental board was found to be about 22–24%, in comparison to 25–30% present in most wood species. There was good correlation between the detection of free water by MRI and by destructive testing. Magnetic resonance images showed various major points of water entry in the WPC boards such as the support area, the cut ends, the dripping edge and the sides of the boards. For the experimental board, significant water entry also occurred at the upper exposed surface.  相似文献   

Micropropagation of mature Calabrian pine (Pinus brutia Ten.) from fascicular buds   总被引：1，自引：0，他引：1  

Abdullah AA  Yeoman MM  Grace J 《Tree physiology》1987,3(2):123-136

Dormant meristems of fascicles explanted from 10-year-old, field-grown trees of Pinus brutia Ten. were cultured in vitro. Browning of cultured fascicles was reduced by including 150 mg l(-1) sodium diethyldithiocarbamate (SDD) in a cytokinin-containing medium. The stage of development of fascicles when placed in culture affected both shoot-bud production and the degree of browning. Only fascicles at an advanced stage of development had a high rate of shoot-bud production. Fascicles cultured for 6 weeks in initiation medium containing 150 mg l(-1) SDD and then for 4 weeks in initiation medium containing 1 mg l(-1) insoluble polyvinylpolypyrrolidone showed the highest rate (23%) of shoot-bud development and the lowest rate (15%) of browning. Elongation of activated shoot buds was considerably enhanced by reducing the concentration of cytokinin in the culture medium. Only shoots >/= 20 mm in height were capable of producing further crops of buds and shoots. When treated with a combination of auxin and cytokinin, only 16% of the elongated shoots produced roots.  相似文献   

Peri-parturient rise of Cryptosporidium oocysts in cows: New insights provided by duplex quantitative real-time PCR     

De Waele V  Berzano M  Speybroeck N  Berkvens D  Mulcahy GM  Murphy TM 《Veterinary parasitology》2012,189(2-4):366-368

In order to clarify if a peri-parturient rise of Cryptosporidium parvum oocysts occurs in cows, faecal samples from 42 cows on two farms were collected. These samples were taken during the pre-parturient, the peri-parturient and the post-parturient periods. Two methods were used to detect the oocysts, a nested-PCR coupled with sequencing and a duplex real-time PCR (qPCR) that quantified Cryptosporidium spp. DNA concentration. The qPCR results were adjusted using a hierarchical Bayesian model taking into account within and between run variation. Generalised Estimating Equation models (GEE) were used to determine if peri-parturient cows were at greater risk of being infected than pre- or post-parturient cows. Fourteen dairy cows exhibited a peri-parturient and post-parturient rise in the excretion of Cryptosporidium spp. oocysts, other than the zoonotic C. parvum. The cows in the suckler beef farm were the only ones infected with the zoonotic species C. parvum at calving. Due to the low concentration of oocysts excreted mainly from species other than C. parvum, it would appear unlikely that cows act as a source of infection for their calves or contribute significantly to environmental contamination.  相似文献   

Efficiency of Two Enucleation Methods Connected to Handmade Cloning to Produce Transgenic Porcine Embryos     

J Li  K Villemoes  Y Zhang  Y Du  PM Kragh  S Purup  Q Xue  AM Pedersen  AL Jørgensen  JE Jakobsen  L Bolund  H Yang  G Vajta 《Reproduction in domestic animals》2009,44(1):122-127

The purpose of our work was to establish an efficient-oriented enucleation method to produce transgenic embryos with handmade cloning (HMC). After 41–42 h oocytes maturation, the oocytes were further cultured with or without 0.4 μg/ml demecolcine for 45 min [chemically assisted handmade enucleation (CAHE) group vs polar body (PB) oriented handmade enucleation (OHE) group respectively]. After removal of the cumulus cells and partial digestion of the zona pellucida, oocytes with visible extrusion cones and/or polar bodies attached to the surface were subjected to oriented bisection. Putative cytoplasts without extrusion cones or PB were selected as recipients. Two cytoplasts were electrofused with one transgenic fibroblasts expressing green fluorescent protein (GFP), while non-transgenic fibroblasts were used as controls. Reconstructed embryos were cultured in Well of Wells (WOWs) with porcine zygote medium 3 (PZM-3) after activation. Cleavage and blastocyst rates were registered on day 2 and day 7 of in vitro culture respectively. Meanwhile, the total blastocyst cell number was counted on day 7. We found that the difference was only observed between blastocyst rates (38.6 ± 2% vs 48.1 ± 3%) of cloned embryos with GFP transgenic fibroblast cells after CAHE vs OHE. With adjusted time-lapse for zonae-free cloned embryos cultured in WOWs with PZM-3, it was obvious that in vitro developmental competence after CAHE was compromised when compared with the OHE method. OHE enucleation method seems to be a potential superior alternative method used for somatic cell nuclear transfer (SCNT) with transgenic fibroblast cells.  相似文献   

Carbon dioxide as a potential fumigant for termite control     

Kathleen M. Delate  J. Kenneth Grace  John W. Armstrong  Carrie H. M. Tome 《Pest management science》1995,44(4):357-361

Formosan subterranean termites, Coptotermes formosanus Shiraki, were exposed to ? 95% or 50% carbon dioxide atmospheres for intervals of 24-120 h at 26(±3)°C. A 24-h exposure to ? 95% carbon dioxide caused significant termite mortality, but 60 h were required for complete mortality. Exposure to 50% carbon dioxide for 60 h resulted in approximately 70% termite mortality, while complete mortality was recorded after 120 h. When termites were sealed in wooden blocks (90 × 90 × 152 mm), 72-96 h exposure to ? 95% carbon dioxide was necessary for complete control. A limited study with Cryptotermes brevis (Walker) suggested that this drywood termite is also susceptible to carbon dioxide fumigation, although slightly longer exposures may be required than with C. formosanus. Carbon dioxide-modified atmospheres are a viable alternative to conventional fumigants for vault fumigation of termite-infested materials, and may also be applicable to larger-scale fumigations to control structural pests.  相似文献   

Understanding bovine trypanosomiasis and trypanotolerance: the promise of functional genomics     

Hill EW  O'Gorman GM  Agaba M  Gibson JP  Hanotte O  Kemp SJ  Naessens J  Coussens PM  MacHugh DE 《Veterinary immunology and immunopathology》2005,105(3-4):247-258

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Effect of protein level and flushing method on the reproductive performance of rabbits     

Grace T. IYEGHE-ERAKPOTOBOR  Shade A. S. OLORUNJU  Emmanuel O. OYEDIPE 《Animal Science Journal》2005,76(3):209-215

Fifty‐five New Zealand white × California cross‐bred female rabbits were used to study the effect of protein level and flushing method on the reproductive performance of rabbits. The treatments consisted of three protein diets (18, 20 and 24% crude protein (CP)) and three flushing methods in a 3 × 3 factorial design. The flushing methods consisted of (i) flushing multiparous does and feeding a 16% CP diet during pregnancy; (ii) flushing multiparous does and feeding an 18% CP diet during pregnancy; and (iii) flushing nulliparous does and feeding an 18% CP diet during pregnancy. Flushing rabbits with different levels of protein did not significantly affect gestation length, litter size and mortality of kits. The trend showed an increase in litter weight with the increase in protein level from 18 to 24%. However, kits from does flushed with 24% CP had a higher individual kit weight gain than those on 20 and 18% CP. Gestation length, total litter size at birth, number of kits dead at birth and number of kits dead at 21 days post‐partum were not affected by flushing methods. There was, however, a significant effect of the flushing method on the number of kits alive at birth, and 7, 14 and 21 days post‐partum. Nulliparous does flushed and maintained on 18% CP during pregnancy had a significantly higher number of kits alive at birth, and 7, 14 and 21 days post‐partum. Litter weight was significantly higher for nulliparous does at 7, 14 and 21 days compared with that of multiparous does flushed and placed on a 16 or 18% CP diet during pregnancy. Protein intake during pregnancy had a significant effect on litter birthweight. Nulliparous and multiparous does flushed and placed on an 18% CP diet during pregnancy had a significantly higher litter birthweight than multiparous does flushed and placed on a 16% CP diet during pregnancy. The effect of protein level during pregnancy on the number of kits alive at birth was not significant. There was no interaction between protein level and flushing method on the reproductive performance of rabbits.  相似文献