Genetic estimates of population structure and dispersal in a benthic stream fish     

Bradley A. Lamphere  Michael J. Blum 《Ecology of Freshwater Fish》2012,21(1):75-86

Abstract–  Comparing genetic and demographic estimates of dispersal in freshwater fish can improve understanding of movement distributions and population connectivity. Here we examined genetic variation among mottled sculpin (Cottus bairdi) in the Nantahala River (North Carolina, USA) to compare genetic estimates of dispersal with estimates derived from mark–recapture studies of individual movement. Microsatellite‐based analysis of gene flow revealed evidence of strong isolation by distance among locations spanning only 5.6 km and limited dispersal among clusters of sites separated by swift cascades. Estimates of between‐cluster contemporary dispersal rates derived from Bayesian assignment tests ranged from 1% to 6%, with most movement occurring among adjacent clusters in a downstream direction. Evidence of a long‐term net immigration asymmetry and decreasing genetic diversity from downstream to upstream locations indicates that historical patterns of stream colonisation contrast with contemporary dispersal patterns. Our findings are largely consistent with predictions from individual movement patterns but suggest that long moves (>500 m) are more frequent, and maximum dispersal distances are greater than what has been reported from mark–recapture studies. The discrepancy may reflect spatial limitations of mark–recapture methods or temporal variation in dispersal in individuals and populations.  相似文献   

Susceptibility of different Eucalyptus genotypes to artificial leaf-inoculations with Cylindrocladium scoparium and C. clavatum     

L. E. B. Blum  J. C. Dianese 《Forest Pathology》1993,23(5):276-280

Young plants of 38 Eucalyptus seed sources were inoculated in the laboratory with conidia of Cylindrocladium scoparium and C. clavatum. Susceptibility was principally assessed in terms of the severity of leaf spotting.  相似文献   

Ontogenesis of mRNA levels and binding sites of hepatic alpha-adrenoceptors in young cattle     

Ontsouka EC  Zbinden Y  Hammon HM  Blum JW 《Domestic animal endocrinology》2006,30(3):170-184

Catecholamines affect hepatic glucose production through (alpha- and beta2-) adrenoceptors (AR). We studied mRNA abundance and binding of hepatic alpha-AR in pre-term (P0) calves and in full-term calves at day 0 (F0), day 5 (F5) and day 159 (F159) to test the hypothesis that gene expression and numbers of hepatic alpha-AR in calves are influenced by age and associated with beta2-AR and selected traits of glucose metabolism. mRNA levels of alpha1- and alpha2-AR were measured by real time RT-PCR. alpha1- and alpha2-AR numbers (maximal binding, Bmax) were determined by saturation binding of (3H)-prazosin and (3H)-RX821002, respectively. alpha1- and alpha2-AR subtypes were evaluated by competitive binding. alpha1A-AR mRNA levels were lower in P0 than in F0, F5 and F159 and alpha(2AD)-AR mRNA levels were lower in F159 than in P0, F0 and F5, while alpha2C-AR mRNA levels increased from P0 and F0 to F5 and F159. Bmax of alpha1-AR increased from P0 to F5, then decreased in F159. Bmax of alpha2-AR decreased from F0 to F159. Bmax of alpha1-AR was positively associated with mRNA levels of alpha1A-AR (r = 0.7), Bmax of beta2-AR (r = 0.5) and negatively with hepatic glycogen content (r = -0.6). Bmax of alpha2-AR was negatively associated with Bmax of beta2-AR (r = -0.4). In conclusion, mRNA levels and binding sites of alpha1- and alpha2-AR in calves exhibited developmental changes and were negatively associated with hepatic glycogen content.  相似文献   

Conformational switches modulate protein interactions in peptide antibiotic synthetases     

Koglin A  Mofid MR  Löhr F  Schäfer B  Rogov VV  Blum MM  Mittag T  Marahiel MA  Bernhard F  Dötsch V 《Science (New York, N.Y.)》2006,312(5771):273-276

Protein dynamics plays an important role in protein function. Many functionally important motions occur on the microsecond and low millisecond time scale and can be characterized by nuclear magnetic resonance relaxation experiments. We describe the different states of a peptidyl carrier protein (PCP) that play a crucial role in its function as a peptide shuttle in the nonribosomal peptide synthetases of the tyrocidine A system. Both apo-PCP (without the bound 4'-phosphopantetheine cofactor) and holo-PCP exist in two different stable conformations. We show that one of the apo conformations and one of the holo conformations are identical, whereas the two remaining conformations are only detectable by nuclear magnetic resonance spectroscopy in either the apo or holo form. We further demonstrate that this conformational diversity is an essential prerequisite for the directed movement of the 4'-PP cofactor and its interaction with externally acting proteins such as thioesterases and 4'-PP transferase.  相似文献   

Conversion of Cortisone to Cortisol and Prostaglandin F2α Production by the Reproductive Tract of Cows at the Late Luteal Stage In Vivo     

HT Duong  DJ Skarzynski  KK Piotrowska‐Tomala  MM Bah  K Jankowska  P Warmowski  K Łukasik  K Okuda  TJ Acosta 《Reproduction in domestic animals》2012,47(6):939-945

Previous in vitro studies demonstrated that bovine endometrium has the capacity to convert inactive cortisone to biologically active cortisol (Cr) and that Cr inhibits cytokine‐stimulated prostaglandin F_2α (PGF) production. This study was carried out to test the hypothesis that bovine reproductive tract has the capacity to convert cortisone to Cr in vivo and to evaluate the effects of intravaginal application of exogenous cortisone on uterine PGF secretion during the late luteal stage. The temporal relationships between PGF and Cr levels in uterine plasma were also determined. Catheters were inserted into jugular vein (JV), uterine vein (UV), vena cava caudalis (VCC) and aorta abdominalis (AA) of six cows on Day 15 of the oestrous cycle (ovulation = Day 0) for frequent blood collection. On Day 16, the cows were divided randomly into two groups and infused intravaginally with vaseline gel (10 ml; control; n = 3) or cortisone dissolved in vaseline gel (100 mg; n = 3). Blood samples were collected at ?2, ?1, ?0.5, 0, 0.5, 1, 1.5, 2, 3, 4, 5 and 6 h after treatments (0 h). Intravaginal application of cortisone increased plasma concentrations of Cr between 0.5 and 1.5 h in UV, at 0.5 h in VCC, at 1 h in JV and at 1.5 h in AA. The plasma concentrations of PGF in UV and of PGF metabolite in JV were greater at 0.5 and 1 h in the cortisone‐treated animals than in control animals. The levels of PGF in UV blood plasma decreased after Cr reached its highest levels. The overall findings suggest that the female reproductive tract has the capacity to convert cortisone to Cr in vivo. Based on the temporal changes of PGF and Cr levels in the uterine plasma, a biphasic response in PGF secretion was found to be associated to the Cr increase induced by the cortisone treatment at the late luteal stage in non‐pregnant cows.  相似文献   

Effects of Matrix Filtration of Low-Quality Boar Semen Doses on Sperm Quality     

E Bussalleu  E Pinart  MM Rivera  M Briz  S Sancho  M Yeste  I Casas  A Fàbrega  T Rigau  JE Rodriguez-Gil  S Bonet 《Reproduction in domestic animals》2009,44(3):499-503

The aim of this work was to develop a method to enhance the sperm parameters of ejaculates with low sperm quality from Piétrain boars. Seminal doses were filtered through columns of DEAE Sephadex (length 2.5 ± 0.5 cm), CM Sephadex (length 5 ± 0.5 cm), glass wool (length 2 ± 0.5 cm) or glass bead (length 10 ± 0.5 cm), with an exit flow rate of 1 ml/40 s in all cases. For each male, 10 ml of the sperm cell-rich fraction diluted at 1 : 6 were filtered. Sperm quality was assessed before and after filtration. Sperm morphology, sperm motility and sperm concentration were determined using the computer program sca ^® 2002 Production, and sperm viability was evaluated by fluorescence multistaining. Osmotic resistance test and hyperosmotic resistance test were used to determine the osmotic resistance of spermatozoa, whereas l -lactate production estimated the metabolic activity. Results showed a decrease of sperm concentration and osmotic resistance of spermatozoa after filtration in the four matrixes. However, an increase in the frequency of viable spermatozoa with intact acrosome after filtration in glass bead columns and an increase of morphologically normal spermatozoa after filtration in Sephadex CM-50, glass wool and glass bead columns were observed. Despite the decrease in the frequency of progressive motile spermatozoa, l -lactate production and mitochondrial sheath integrity maintained constant after filtration. Our findings indicate that column filtration is an effective method to enhance the sperm quality by selecting viable and morphologically normal spermatozoa without altering DNA, plasma membrane, mitochondrial sheath integrity or inducing premature acrosome reaction.  相似文献   

Clinical and Subclinical Endometritis in the Mare: Both Threats to Fertility     

MM LeBlanc  RC Causey 《Reproduction in domestic animals》2009,44(S3):10-22

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Effects of L-carnitine fed during gestation and lactation on sow and litter performance   总被引：1，自引：0，他引：1  

Musser RE  Goodband RD  Tokach MD  Owen KQ  Nelssen JL  Blum SA  Dritz SS  Civis CA 《Journal of animal science》1999,77(12):3289-3295

Multiparous sows (n = 307) were used to evaluate the effects of added dietary L-carnitine, 100 mg/d during gestation and 50 ppm during lactation, on sow and litter performance. Treatments were arranged as a 2 (gestation or lactation) x2 (with or without L-carnitine) factorial. Control sows were fed 1.81 kg/d of a gestation diet containing .65% total lysine. Treated sows were fed 1.59 kg/d of the control diet with a .23 kg/d topdressing of the control diet that provided 100 mg/d of added L-carnitine. Lactation diets were formulated to contain 1.0% total lysine with or without 50 ppm of added L-carnitine. Sows fed 100 mg/d of added L-carnitine had increased IGF-I concentration on d 60 (71.3 vs. 38.0 ng/mL, P<.01) and 90 of gestation (33.0 vs. 25.0 ng/mL, P = .04). Sows fed added L-carnitine had increased BW gain (55.3 vs 46.3 kg; P<.01) and last rib fat depth gain (2.6 vs. 1.6 mm; P = .04) during gestation. Feeding 100 mg/d of added L-carnitine in gestation increased both total litter (15.5 vs. 14.6 kg; P = .04) and pig (1.53 vs 1.49 kg; P<.01) birth weight. No differences were observed in pig birth weight variation. Added L-carnitine fed during gestation increased litter weaning weight (45.0 vs. 41.3 kg, P = .02); however, no effect of feeding L-carnitine during lactation was observed. No differences were observed in subsequent days to estrus or farrowing rate. Compared to the control diet, feeding added L-carnitine in either gestation, lactation, or both, increased (P<.05) the subsequent number of pigs born alive, but not total born. In conclusion, feeding L-carnitine throughout gestation increased sow body weight and last rib fat depth gain and increased litter weights at birth and weaning.  相似文献   

Plasma leptin status in young calves: effects of pre-term birth, age, glucocorticoid status, suckling, and feeding with an automatic feeder or by bucket     

Blum JW  Zbinden Y  Hammon HM  Chilliard Y 《Domestic animal endocrinology》2005,28(2):119-133

Plasma leptin concentrations depend on energy intake and fat stores and are modified by hormones, such as glucocorticoids. We have measured plasma leptin concentrations in pre-term calves (born on day 277 of gestation) during the first week of life, in full-term calves (290 days of gestation), fed similar amounts of nutrients with colostrum or a milk-derived formula, combined with or without dexamethasone treatment (to simulate a high glucocorticoid status), during the first five days of life, and in calves fed with an automatic feeder or by bucket or suckling on dams up to day 28. Leptin concentrations increased (P<0.05) from birth to day 7 in pre-term calves. In full-term calves leptin concentrations were stable from day 1 to day 4 in colostrum-fed animals, but decreased (P<0.05) and were lower (P<0.05) if fed a formula with similar amounts of energy and macronutrients as colostrum. Concentrations increased (P<0.05) from day 1 to day 2 in calves suckling on dams and then remained elevated, but did not change and were lower in calves fed with the automatic feeder or by bucket than in suckling calves. Dexamethasone only slightly elevated leptin concentrations. There was no episodic secretion pattern, and there were no consistent associations of leptin with various metabolites and hormones. In conclusion, plasma leptin in young calves with respect to effects of nutrition (low energy intake) and hormones (glucocorticoids) and in association with metabolic changes behaved differently from what is known in mature cattle.  相似文献   

Canine panosteitis--an idiopathic bone disease investigated in the light of a new hypothesis concerning pathogenesis. Part two: Biochemical aspects and investigations     

Schawalder P  Jutzi K  Andres HU  Blum J 《Schweizer Archiv für Tierheilkunde》2002,144(4):163-173

The pilot study included serum analysis of ionized calcium, copper, zinc, various hormones and amino acid profiles from dogs affected with panosteitis, as well as protein electrophoresis performed on bone biopsies. Results of these analyses are as follows: ionized calcium, copper, zinc and hormones (parathyroid hormone, IGF-1, T3 and T4) were within reference ranges. Eleven of 23 serum amino acids from panosteitis-affected dogs were found to be significantly increased (P = 0.05). SDS-polyacrylamide gel electrophoresis performed on bone biopsies, which were pretreated with SDS, resulted in a double band of 39,000 D molecular weight in all panosteitis-affected dogs. Similar studies in control dogs resulted in a single band in this region. Attempts at amino acid sequencing from the N-terminal of the proteins in this double band region were unsuccessful. A chemical interference at the N-terminal end of these proteins was suspected. The composition of this double band is as yet unknown. The etiology of panosteitis could therefore not be definitively verified. However, it does appear that protein- or amino acid metabolism is affected in dogs with panosteitis.  相似文献