Influence of the FecXR Allele in Heterozygous Ewes on Follicular Population and Outcomes of IVP and ET using LOPU‐Derived Oocytes     

B Lahoz  JL Alabart  J Folch  P Sánchez  E Echegoyen  MJ Cocero 《Reproduction in domestic animals》2013,48(5):717-723

Ewes heterozygous for the FecX^R allele (R+) in the bone morphogenetic protein 15 (BMP15) gene display increased ovulation rate and prolificacy. Besides this phenotypic advantage, the influence of the FecX^R allele on follicle number and size, oocyte competence and in vitro production (IVP) remains undefined. With these aims, 8 R+ and 8 wild‐type (++) ewes were subjected to 2 laparoscopic ovum pick‐up (LOPU) trials (four sessions per trial; two with and two without FSH) and subsequent IVP and fresh embryo transfer. All follicles >3 mm were punctured (n = 1673). Genotype did not significantly affect the number of punctured follicles per ewe and session (10.4 and 10.2 in R+ and ++ untreated ewes, 17.4 and 14.3 in R+ and ++ FSH‐treated ewes, respectively), but follicular diameter of R+ ewes was significantly reduced compared with ++ ewes (?0.2 mm in untreated and ?0.8 mm in FSH‐treated ewes; p < 0.01). R+ ewes showed higher recovery rate and increased numbers of total and suitable cumulus–oocyte complexes for in vitro maturation (IVM). Similar rates of day 8 blastocysts were observed in R+ (36.1%, 147/407) and ++ (32.6%, 100/307) ewes, but the final output of day 8 blastocysts per ewe and session was higher in R+ ewes (+0.75; p < 0.005), without differences in survival rate at birth of the transferred embryos (40.4%, 21/52 vs 36.4%, 16/44, respectively). In conclusion, a higher number of oocytes proven to be competent for in vitro development and embryo survival after transfer are recovered from R+ ewes, despite the lower mean size of their follicles at puncture.  相似文献   

The UVA and aqueous stability of flavonoids is dependent on B-ring substitution     

Maini S  Hodgson HL  Krol ES 《Journal of agricultural and food chemistry》2012,60(28):6966-6976

Flavonols such as kaempferol and quercetin are believed to provide protection against ultraviolet (UV)-induced damage to plants. Recent in vitro studies have examined the ability of flavonols to protect against UV-induced damage to mammalian cells. Stability of flavonols in cell culture media, however, has been problematic, especially for quercetin, one of the most widely studied flavonols. As part of our investigations into the potential for flavonols to protect skin against UV-induced damage, we have determined the stability of a series of flavonols that differ only in the number of substituents on the B-ring. We measured the stability of these flavonols over time to UVA radiation, Dulbecco's modified Eagle's medium (DMEM), and Dulbecco's phosphate-buffered saline (DPBS) using high performance liquid chromatography with UV detection (HPLC-UV). The identification of the breakdown products of flavonols was accomplished by using a hybrid quadrupole linear ion trap mass spectrometer coupled with liquid chromatography. Tandem mass spectrometric analysis (MS/MS) of flavonol photoproducts was confirmed by comparing with the known standard samples. We have determined that flavonol stability decreases with increasing B-ring substitution, suggesting that future investigation of potential photoprotective flavonols will need to be cognizant of this trend.  相似文献   

The Role of Weather in Meningitis Outbreaks in Navrongo, Ghana: A Generalized Additive Modeling Approach     

Vanja Duki?  Mary Hayden  Abudulai Adams Forgor  Tom Hopson  Patricia Akweongo  Abraham Hodgson  Andrew Monaghan  Christine Wiedinmyer  Tom Yoksas  Madeleine C. Thomson  Sylwia Trzaska  Raj Pandya 《Journal of Agricultural, Biological & Environmental Statistics》2012,17(3):442-460

Bacterial (meningococcal) meningitis is a devastating infectious disease with outbreaks occurring annually during the dry season in locations within the ??Meningitis Belt??, a region in sub-Saharan Africa stretching from Ethiopia to Senegal. Meningococcal meningitis occurs from December to May in the Sahel with large epidemics every 5?C10?years and attack rates of up to 1000 infections per 100,000 people. High temperatures coupled with low humidity may favor the conversion of carriage to disease as the meningococcal bacteria in the nose and throat are better able to cross the mucosal membranes into the blood stream. Similarly, respiratory diseases such as influenza and pneumonia might weaken the immune defenses and add to the mucosa damage. Although the transmission dynamics are poorly understood, outbreaks regularly end with the onset of the rainy season and may begin anew with the following dry season. In this paper, we employ a generalized additive modeling approach to assess the association between number of reported meningitis cases and a set of weather variables (relative humidity, rain, wind, sunshine, maximum and minimum temperature). The association is adjusted for air quality (dust, carbon monoxide), as well as varying degrees of unobserved time-varying confounding processes that co-vary with both the disease incidence and weather. We present the analysis of monthly reported meningitis counts in Navrongo, Ghana, from 1998?C2008.  相似文献   

Spatial pattern formation in an insect host-parasitoid system     

JL Maron  S Harrison 《Science (New York, N.Y.)》1997,278(5343):1619-1621

Spatial models in ecology predict that populations may form patchy distributions within continuous habitats, through strong predator-prey or host-parasitoid interactions combined with limited dispersal. Empirical support of these models is provided. Parasitoids emanating from a population outbreak of tussock moths (Orgyia vetusta) suppressed the growth of nearby experimental populations of the moth, while experimental populations farther away were able to grow. This result explains the observed localized nature of tussock moth outbreaks and illustrates how population distributions can be regulated by dynamic spatial processes.  相似文献   

Tyrosinase reactivity in a model complex: an alternative hydroxylation mechanism   总被引：1，自引：0，他引：1  

Mirica LM  Vance M  Rudd DJ  Hedman B  Hodgson KO  Solomon EI  Stack TD 《Science (New York, N.Y.)》2005,308(5730):1890-1892

The binuclear copper enzyme tyrosinase activates O2 to form a mu-eta2:eta2-peroxodicopper(II) complex, which oxidizes phenols to catechols. Here, a synthetic mu-eta2:eta2-peroxodicopper(II) complex, with an absorption spectrum similar to that of the enzymatic active oxidant, is reported to rapidly hydroxylate phenolates at -80 degrees C. Upon phenolate addition at extreme temperature in solution (-120 degrees C), a reactive intermediate consistent with a bis-mu-oxodicopper(III)-phenolate complex, with the O-O bond fully cleaved, is observed experimentally. The subsequent hydroxylation step has the hallmarks of an electrophilic aromatic substitution mechanism, similar to tyrosinase. Overall, the evidence for sequential O-O bond cleavage and C-O bond formation in this synthetic complex suggests an alternative intimate mechanism to the concerted or late stage O-O bond scission generally accepted for the phenol hydroxylation reaction performed by tyrosinase.  相似文献   

Comparison of some responses to exercise on the track and the treadmill in French trotters: determination of the optimal treadmill incline     

Couroucé A  Corde R  Valette JP  Cassiat G  Hodgson DR  Rose RJ 《Veterinary journal (London, England : 1997)》2000,159(1):57-63

The purpose of this study was to determine the optimal treadmill slope for trotters to produce the same heart rate and blood lactate responses as on the track during a standardized exercise test. Nine 2-year-old French trotters performed exercise tests on a training track and on a treadmill set at an incline of 0, 2 or 4%. For all horses, track testing was performed on day 1 and then on the treadmill according to a Latin-square design. The track test utilized three steps each of 3 min at speeds of 470, 530, 590 m/min and the same speeds were used on the treadmill. Derived physiological variables such as the speed at a HR of 200 bpm (V(200)) and the speed inducing blood lactate concentrations of 4 mmol/L (V(4)) were calculated. There were significant differences for V(200)and V(4)(P<0.05) between the track and the treadmill data when the treadmill was set at inclines of 0 and 4%, but no significant differences with the treadmill set at a 2% incline. The optimal treadmill incline to reproduce similar responses to those on the track was determined by regression analysis, and was found to be 2.4% for the two most often utilized derived physiological variables, V(4)and V(200).  相似文献   

Long‐term assessment of horses and ponies post exposure to monensin sodium in commercial feed     

K. J. Hughes  K. L. Hoffmann  Dr D. R. Hodgson 《Equine veterinary journal》2009,41(1):47-52

Reasons for performing study: Acute monensin intoxication in equids is well described; however, the long‐term effects of sublethal intoxication and ability to return to previous use are less well understood. Long‐term observations may allow improved estimation of prognosis in cases of sublethal intoxication. Objectives: To assess horses and ponies exposed to sublethal amounts of monensin for evidence of chronic sequelae and ability to return to prior/intended use. Methods: Twenty‐nine horses and 8 ponies were assessed utilising serum biochemistry, treadmill exercise stress testing, electrocardiography, and pre‐ and post exercise echocardiography ≥6 weeks after ingestion of monensin‐contaminated feed. Animals with evidence of monensin‐induced cardiomyopathy were re‐examined after a period of rest of ≥11 months. Follow‐up information was obtained by owner telephone interview ≥52 months after exposure. Results: During resting echocardiography, 11 animals had reduced/low‐normal left ventricular fractional shortening (FS); an increase in FS in 8 of these animals was measured ≥11 months later. Six animals had reduced or low‐normal FS during post exercise echocardiography. Two horses had ventricular premature depolarisations during exercise. Follow‐up information was available for 35 animals: 21 returned to athletic/reproductive use, 13 were retired immediately and one died. Mean FS increased significantly (P<0.001) between initial and second examination in 15 animals that underwent resting echocardiography on 2 occasions. Conclusions: Some equids exposed to sublethal doses of monensin may not develop permanent myocardial disease and a return to athletic/reproductive use is possible. Potential relevance: Exercise stress testing, echocardiography and electrocardiography may be useful for detection and monitoring of cardiac dysfunction in equids exposed to monensin and determining whether a return to athletic/reproductive use is possible.  相似文献   

Identification of immunogenic proteins associated with protection against haemorrhagic septicaemia after vaccination of calves with a live-attenuated aroA derivative of Pasteurella multocida B:2     

Saeed Ataei  Richard Burchmore  J. Christopher Hodgson  Anna Finucane  Roger Parton  John G. Coote   《Research in veterinary science》2009,87(2):207-210

Pasteurella multocida serotype B:2 is the causative agent of haemorrhagic septicaemia (HS), a fatal disease of cattle and buffaloes. As a step towards the identification of individual antigens that may protect against HS, proteins present in a sonicated cell extract (SCE) and outer-membrane protein (OMP) preparation of a wild-type P. multocida serotype B:2 were investigated by immunoblotting with sera from calves which had been protected against challenge with a virulent strain of P. multocida B:2 by vaccination with a live-attenuated aroA derivative of the challenge strain. Five proteins in SCE, of approximately 50, 37, 30, 26 and 16 kDa, were recognised by the sera. In an OMP preparation, two bands, at 37 and 50 kDa, were recognised as strongly immunogenic. Mass spectrometry analysis of proteins corresponding in size to those detected by immunoblotting identified the 37 kDa band as OmpA, but the band at 50 kDa was not identified with certainty. A major 30 kDa OMP, identified as OmpH, was not strongly immunogenic.  相似文献