The composite genome of the legume symbiont Sinorhizobium meliloti     

Galibert F  Finan TM  Long SR  Puhler A  Abola P  Ampe F  Barloy-Hubler F  Barnett MJ  Becker A  Boistard P  Bothe G  Boutry M  Bowser L  Buhrmester J  Cadieu E  Capela D  Chain P  Cowie A  Davis RW  Dreano S  Federspiel NA  Fisher RF  Gloux S  Godrie T  Goffeau A  Golding B  Gouzy J  Gurjal M  Hernandez-Lucas I  Hong A  Huizar L  Hyman RW  Jones T  Kahn D  Kahn ML  Kalman S  Keating DH  Kiss E  Komp C  Lelaure V  Masuy D  Palm C  Peck MC  Pohl TM  Portetelle D  Purnelle B  Ramsperger U  Surzycki R  Thebault P  Vandenbol M  Vorholter FJ 《Science (New York, N.Y.)》2001,293(5530):668-672

The scarcity of usable nitrogen frequently limits plant growth. A tight metabolic association with rhizobial bacteria allows legumes to obtain nitrogen compounds by bacterial reduction of dinitrogen (N2) to ammonium (NH4+). We present here the annotated DNA sequence of the alpha-proteobacterium Sinorhizobium meliloti, the symbiont of alfalfa. The tripartite 6.7-megabase (Mb) genome comprises a 3.65-Mb chromosome, and 1.35-Mb pSymA and 1.68-Mb pSymB megaplasmids. Genome sequence analysis indicates that all three elements contribute, in varying degrees, to symbiosis and reveals how this genome may have emerged during evolution. The genome sequence will be useful in understanding the dynamics of interkingdom associations and of life in soil environments.  相似文献   

Controlling microbial contamination on beef and lamb meat during processing   总被引：2，自引：0，他引：2  

PR WIDDERS  KJ COATES  S. WARNER  JC BEATTIE  IR MORGAN  MW HICKEY† 《Australian veterinary journal》1995,72(6):208-211

SUMMARY The microbiological quality of carcases, meat and environmental surfaces was evaluated in commercial boning rooms processing beef and lamb. There was considerable variation in the level of microbial contamination on both carcases and meat, with counts ranging from less than 20 to 10⁸/cm² on carcases and to 2 times 10⁷/cm² on meat. The level of microbial contamination on meat was influenced by the level of carcase contamination at boning and by the boning process itself. Carcase contamination was the major determinant of microbiological quality, as more than 70% of carcases had microbial counts greater than 10³/cm². Cutting boards were a major source for microbial dissemination during boning, particularly when carcase counts were less than 10³/cm². If carcases were heavily contaminated, the contamination of processing surfaces was irrelevant in determining microbial loads on meat. Where carcase contamination was at low to moderate levels, the contribution of the boning process to the contamination on meat assumed increased significance. Under these conditions, improved sanitation of cutting surfaces in the boning room resulted in a significant reduction in microbial contamination on the surface of meat. These results can form the basis for ensuring that improvements made in carcase management before boning, to improve microbiological quality, will be preserved through attention to cutting board hygiene during boning.  相似文献   

Tissue Distribution of Enrofloxacin in Fingerling Rainbow Trout Oncorhynchus mykiss Following Different Doses of Oral Administration     

Hui-Min  Hsu  Gregory A.  Wooster Paul R.  Bowser 《Journal of the World Aquaculture Society》1994,25(4):535-540

Rainbow trout Oncorhynchus mykiss were fed a ration medicated to provide enrofloxacin (Baytrilo®, Bayer) at 2.5, 5.0, or 10.0 mg drug per kg fish per d either 5 or 10 d. Tissue Concentrations of enrofloxacin were measured in liver, kidney, muscle, skin, and serum during the medication period, and thereafter for a total of 30 d. Highest tissue concentrations were observed in fish medicated with 5 mg enrofloxacin per kg fish per d for 10 d. Tissue concentrations of anitmicrobial activity were found to exceed minimum inhibitory concentrations of enrofloxacin for several isolates of Aeromonas salmonicida and Renibacterium salmoninarum . Lower than expected tissue concentrations were observed for the 10 mg per kg fish per d doses, perhaps due to a lack of acceptance of the medicated ration. The results support evaluation of a 5 mg per kg fish dose to treat bacterial infections of salmonids under field conditions.  相似文献   

Prevalence of koala retrovirus in geographically diverse populations in Australia     

GS Simmons  PR Young  JJ Hanger  K Jones  D Clarke  JJ McKee  J Meers 《Australian veterinary journal》2012,90(10):404-409

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Impact of molybdenum on the copper status of red deer (Cervus elaphus)     

ND Grace  PR Wilson  AK Quinn 《New Zealand veterinary journal》2013,61(2):137-141

AIM: To determine the effect of increasing molybdenum (Mo) intakes on serum and liver copper (Cu) concentrations and growth rates of grazing red deer (Cervus elaphus).

METHODS: Molybdenum- and Cu-amended fertilisers were applied to six 1.1-ha paddocks in a 3 × 2 design. Three levels of Mo were applied on two paddocks at each level in mid April (designated Day 1); levels were: none (control), 0.5 (medium) and 1.0 (high) kg Mo/ha as sodium molybdate. In late May (Day 39), two levels of Cu (none and 3.0 kg Cu/ha, as copper sulphate) were applied to each of the three levels of Mo-treated paddocks. Pasture Mo, Cu and sulphur (S) concentrations were measured at about fortnightly intervals. In late June (Day 74), ten 6-month-old red deer hinds were placed on the six experimental pastures, and serum and liver Cu concentrations were monitored at about monthly intervals for 102 days. The hinds were weighed on four occasions during the trial.

RESULTS: Mean pasture Mo concentrations on Day 56 were 2, 4.6 and 11.3 mg/kg dry matter (DM) for the untreated control, medium and high Mo-treated pastures, respectively. Pasture Cu concentration was 95 mg/kg DM on Day 59, 53 mg/kg DM on Day 90, and 9 mg/kg DM by Day 153. Mean S concentration in pasture was 3.3 (range 3.03–3.45) g/kg DM. Copper application to pasture had no significant effect on serum and liver Cu concentrations in deer so data were pooled within Mo treatment. Mean initial (Day 74) serum Cu concentration was 9.2 µmol/L. In the deer grazing the control Mo pasture, this increased to 10.3 µmol/L on Day 112, before decreasing to 6.4 µmol/L on Day 176. In deer grazing the medium and high Mo-treated pastures, mean serum Cu concentrations were 3.8 and 3.9 µmol/L, respectively, on Day 112, and 2.5 and 3.3 µmol/L, respectively, on Day 176. Mean initial (Day 74) liver Cu concentration was 131 µmol/kg fresh tissue. In the deer grazing the control Mo pasture, this declined to 120 and 52 µmol/kg on Days 112 and Day 176, respectively. In deer grazing the medium and high Motreated pastures, liver Cu concentrations decreased to 55 and 52 µmol/kg fresh tissue, respectively, on Day 112, and 21 and 20 µmol/kg fresh tissue, respectively, on Day 176. Mean serum and liver Cu concentrations were not significantly different between deer grazing the medium and high Mo-treated pastures, and were lower (serum p=0.003, liver p<0.001) in those groups than in deer grazing the untreated control pastures. No clinical signs of Cu deficiency associated with lameness were observed. Deer grazing pastures that had Mo concentrations >10 mg/kg DM had lower (p=0.002) growth rates (100 vs 130 g/day) than those on pastures containing <2.4 mg Mo/kg DM.

CONCLUSION: Increasing pasture Mo concentrations from 2 mg/kg DM to ≥4.6 mg/kg DM significantly reduced serum and liver Cu concentrations in grazing deer. Reduced growth rate was observed at pasture Mo concentrations >10 mg/kg DM.  相似文献   

Dystocia in beef heifers: A review of genetic and nutritional influences     

RE Hickson  ST Morris  PR Kenyon  N Lopez-Villalobos 《New Zealand veterinary journal》2013,61(6):256-264

Breeding beef heifers for the first time at 15 months of age has potential to increase the efficiency of the beef breeding-cow herd. An increased incidence of dystocia in heifers calving at 2 years of age, compared to mature cows, is a major reason many farmers in New Zealand have not adopted the practice. The predominant type of dystocia affecting 2-year-old heifers is feto-maternal disproportion, a condition in which the fetus is too large relative to the size of the heifer's pelvis. Reducing birthweight of the calf is a means of reducing the incidence of dystocia. Birthweight and length of gestation are determined by genotype of the calf, maternal genetic effects and environmental effects.

Bulls with low estimated breeding values for birthweight have been selected for mating heifers; however, the positive genetic correlation between birthweight and mature weight meant that the progeny of these bulls tended to be lighter at finishing, making them less desirable in the beef industry. The genotype of the dam also plays a role in determining the risk of dystocia; the maternal ability of the dam to nurture the fetus influences birth- weight, and the dam's genetic potential for growth influences the size of her pelvic area. Heavy heifers tend to produce high- birthweight calves, counteracting the reduction in the incidence of dystocia resulting from the larger pelvis in larger heifers.

Manipulating feeding level during pregnancy offers an alternative method for manipulating the birthweight of calves. Little is known about the effects of nutrition in early gestation on placental development or birthweight of calves. No differences in the birthweight of calves have been observed in response to variation in feeding in mid-pregnancy, and variable responses in birthweight and the incidence of dystocia to feeding in the third trimester of pregnancy have been reported. Differences in birthweight have not always resulted in differences in the incidence of dystocia, primarily due to differences in liveweight of the heifer also induced by feeding regimens. Variability in the incidence of dystocia in response to feeding level in the third trimester of pregnancy makes it difficult to make recommendations for the feeding of heifers at this stage of gestation. More research is needed into the effects of nutrition in early gestation on fetal and placental development in cattle.  相似文献   

A survey to determine the presence and distribution of largemouth bass virus in wild freshwater bass in New York State     

Groocock GH  Grimmett SG  Getchell RG  Wooster GA  Bowser PR 《Journal of aquatic animal health》2008,20(3):158-164

During 2004 and 2005 a survey was conducted to investigate the presence and geographic distribution of largemouth bass virus (LMBV) in New York State. This iridovirus is widely distributed across the eastern United States; however, it had not previously been reported in New York State. Two hundred and eighty-three wild largemouth bass Micropterus salmoides and 8 smallmouth bass M. dolomieu were collected from 37 locations across the state. No clinical signs of LMBV or mortalities attributable to the virus were observed in the fish collected. Using a quantitative polymerase chain reaction (QPCR) method, we detected LMBV in 28 fish from 13 locations. Viral cytopathic effect in cell culture was observed in 5 fish from 3 locations. The virus isolated from cell culture was confirmed to be LMBV by an independent PCR method. Statistical analysis of the largemouth bass samples collected during 2005 revealed a wide difference in prevalence between the QPCR results and the cell culture results. Analysis of possible predictors, including age, sex, and month collected, showed no significant associations with the QPCR results. This survey confirms the presence and wide distribution of a potentially pathogenic form of LMBV in multiple water systems across New York State.  相似文献   

Cytochrome oxidase gene sequencing reveals channel catfish ovary cell line is contaminated with brown bullhead cells     

Lorelei Ford  Kuttichantran Subramaniam  Thomas B. Waltzek  Paul R. Bowser  Larry Hanson 《Journal of fish diseases》2021,44(1):119-122

The channel catfish (Ictalurus punctatus, Rafinesque) ovary (CCO) cell line is the standard cell line used for channel catfish diagnostics. Next‐gen sequencing studies of a virus cultured in the CCO cells revealed mitochondrial sequences matching those of brown bullhead (Ameiurus nebulosus, Lesueur). Therefore, we systematically performed partial cytochrome oxidase 1 gene sequencing of several sources of the CCO cell line and all matched the brown bullhead and not the channel catfish.  相似文献   

Assessment of perceived farming risks,communication of risk management practices,and evaluation of their efficiency in Pacific white shrimp (Penaeus vannamei) farming—a survey-based cross-sectional study     

M.  Kumaran  Anand  PR.  Kumar  J. Ashok  Muralidhar  M.  Vasagam  K. P. Kumaraguru  Vijayan  K. K. 《Aquaculture International》2021,29(6):2713-2730

Aquaculture International - Pacific white shrimp (Penaeus vannamei) farming is an important commercial aquaculture production system contributing substantially to the economic and societal...  相似文献   

Detection of viral hemorrhagic septicemia virus by quantitative reverse transcription polymerase chain reaction from two fish species at two sites in Lake Superior     

Cornwell ER  Eckerlin GE  Getchell RG  Groocock GH  Thompson TM  Batts WN  Casey RN  Kurath G  Winton JR  Bowser PR  Bain MB  Casey JW 《Journal of aquatic animal health》2011,23(4):207-217

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