AN ECONOMIC ANALYSIS OF TWO SCHEMES FOR THE ANTHELMINTIC CONTROL OF HELMINTHIASIS IN WEANED LAMBS     

N. ANDERSON  R. S. MORRIS  I. K. MCTAGGART 《Australian veterinary journal》1976,52(4):174-180

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ASPECTS OF THE PHYSIO-PATHOLOGY OF PARASITIC GASTRITIS IN THE SHEEP     

D. A. TITCHEN M.A.  B.V.Sc.  N. ANDERSON B.V.Sc.  Ph.D.  † 《Australian veterinary journal》1977,53(8):369-373

Sheep and calves prepared with separated, innervated pouches made from the acid secreting region of the abomasum were given single or multiple infections of Ostertagia spp and comparisons were made of the secretory changes of parasitised and non-parasitised mucosa by means of cannulas placed in the abomasum and pouch. Contrary reactions of the parasite-free pouches and infected main part of the abomasum are described and explained in terms of a two-part hypothesis. The inhibitory effect on acid secretion of the abomasum (resulting in its contents being pH 5 to 7) was postulated to be due to the direct suppressive effects of substances released locally by parasites or injured host tissues, whereas increased secretion of the hormone, gastrin, was thought to account for the stimulatory effects of infection on acid secretion from the pouches. In sheep treated with anthelmintic and then reinfected the inhibitory effects on abomasal pH were not obtained. The hypersecretion from the pouches still persisted.  相似文献   

A Technique for Extensive Field Measurement of Soil Anaerobism by Rusting of Steel Rods     

CARNELL  R.; ANDERSON  M. A. 《Forestry》1986,59(2):129-140

The colour difference between the reaction products of steelrods with and without the presence of oxygen was used to demonstratethe limits of soil anaerobism on rods which were inserted inthe soil for three months or more. Rods corroded consistentlyto give a surface brown/orange zone and a matt grey zone atdepth. The boundary between the two zones was sharp and correspondedwith the top of the capillary fringe in a variety of soil materials;this also correlated with the lower limit of aerobic soil asindicated by oxygen polarographs and the lower Limit of theroot mat formed by Sitka spruce seedlings. The rods offer acheap extensive method of surveying oxygen restrictions to rootingin soils prone to waterlogging.  相似文献   

Monitoring warm-water fish populations in north temperate regions: sampling considerations when using proportional stock density   总被引：1，自引：0，他引：1  

M. J. DIVENS  S. A. BONAR  B. D. BOLDING  E. ANDERSON  P. W. JAMES 《Fisheries Management and Ecology》1998,5(5):383-391

Three lakes were repeatedly sampled at night using boat electric fishing, experimental gill netting, and fyke netting from May to November 1993 to evaluate the feasibility of using proportional stock density (PSD) to monitor warm-water fish populations in Washington State, USA. Additionally, average night-time boat electric fishing catch-per-effort of largemouth bass, Micropterus salmoides (Lacepéde), from 30 Washington lakes was also analysed to determine the amount of effort required to obtain adequate samples for precise PSD estimates. Temporal variations in PSD were not large enough to affect the management of warm-water fish populations in the small Washington lakes studied. However, the considerable effort required to obtain precise PSD estimates may limit its usefulness for warm-water fisheries surveys in the Pacific Northwest. On average, from three to 13 nights of electric fishing effort are needed to capture enough stock-length largemouth bass for PSD estimates, depending on the precision desired (80–95%) and the location of the lake (eastern or western Washington). Catch of stock-length fish can be maximized by using electric fishing for centrarchids and gill netting for yellow perch, Perca flavescens (Mitchill), in June or September. Adequate samples for precise PSD estimates can be difficult to obtain from Pacific Northwestern lakes, even when using recommended gear at optimum sampling times. Inability to capture an adequate sample size for precise PSD estimates may be responsible for some of the fluctuation in PSDs in some studies of warm-water fish populations in northern areas. Managers in other northern climates may find that low sample size may account for large variations in PSDs reported.  相似文献   

Distribution and drift pathways of Greenland halibut (Reinhardtius hippoglossoides) during early life stages in the eastern Bering Sea and Aleutian Islands     

D. SOHN  L. CIANNELLI  J. T. DUFFY‐ANDERSON 《Fisheries Oceanography》2010,19(5):339-353

We describe the spatial distribution and dispersal pathways of Greenland halibut (Reinhardtius hippoglossoides) early life stages based on historical field data from the eastern Bering Sea and adjacent water along the eastern Aleutian Islands. Our results indicate that Greenland halibut from preflexion larvae to newly settled juveniles have a long pelagic duration and are subject to extended drift pathways. Hatching may occur in deep water, below 530 m, and larvae rise in the water column as they grow. Flexion/postflexion larvae are mostly found around the Pribilof Islands over the middle shelf (50–100‐m isobaths) in July, and settling occurs during late summer on the middle shelf near St. Matthew Island. However, given that age‐1 individuals were primarily found on the outer shelf, it appears that Greenland halibut actively move to deeper water with age (or size). The mechanisms of slope–shelf connectivity in preflexion larvae may be related to the Bering Slope Current in the vicinity of both Bering and Pribilof Canyons. This study shows that Greenland halibut early life stages have extensive horizontal ontogenetic migrations in the Bering Sea, and utilize a range of geographic areas over the basin and slope along the Aleutian Islands and in the eastern Bering Sea. Based on these results, it is hypothesized that settlement success and recruitment of Greenland halibut may be influenced by variability in currents and flows of the Bering Sea slope and shelf during their transport.  相似文献   

Influence of mesoscale eddies on ichthyoplankton assemblages in the Gulf of Alaska     

ELIZABETH ATWOOD  JANET T. DUFFY‐ANDERSON  JOHN K. HORNE  CAROL LADD 《Fisheries Oceanography》2010,19(6):493-507

Mesoscale eddies (100–200 km in diameter) propagating along the shelf‐break in the Gulf of Alaska are ubiquitous and have been shown to influence the ecosystem, but their influence on ichthyoplankton species composition and diversity has not been described. Evidence for larval fish entrainment in these eddies was examined using data from a cruise in 2005 that sampled three eastern Gulf of Alaska mesoscale eddies, and sampling that compared shelf to slope ichthyoplankton assemblages in the northern Gulf of Alaska (2002–2004). Hierarchical cluster analysis of oceanographic data showed that stations grouped according to location within an eddy. Species hierarchical cluster analysis revealed a latitudinal turnover in species composition, and an abundant species group. Species richness was correlated with distance from eddy center (P = 0.00025), and assemblages within eddies were significantly different (P < 0.05) from those in surrounding basin and shelf waters. These results suggest that mesoscale eddies propagating along the continental shelf‐break influence larval fish assemblages over the shelf and slope, which has implications for the timing and extent of larval fish distribution in the Gulf of Alaska.  相似文献   

The synthesis of l-ascorbic acid uniformly labeled with C14     

BOTHNER-BY AA  GIBBS M  ANDERSON RC 《Science (New York, N.Y.)》1950,112(2909):363

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Molecular epidemiology of clinical isolates of Pseudomonas aeruginosa isolated from horses in Ireland     

Tazumi A  Maeda Y  Buckley T  Millar B  Goldsmith C  Dooley J  Elborn J  Matsuda M  Moore J 《Irish veterinary journal》2009,62(7):456-459

Clinical isolates (n = 63) of Pseudomonas aeruginosa obtained from various sites in 63 horses were compared using ERIC2 RAPD PCR to determine their genetic relatedness. Resulting banding patterns (n = 24 genotypes) showed a high degree of genetic heterogeneity amongst all isolates examined, indicating a relative non-clonal relationship between isolates from these patients, employing this genotyping technique. This study characterised 63 clinical isolates into 24 distinct genotypes, with the largest cluster (genotype E) accounting for 10/63 (15.9%) of the isolates. ERIC2 RAPD PCR proved to be a highly discriminatory molecular typing tool of P. aeruginosa in isolates recovered from horses. With the adoption of several controls to aid reproducibility, this technique may be useful as an alternative to PFGE, particularly in epidemiological investigations of outbreaks where speed may be a significant parameter. This is the first report of clonal heterogeneity amongst P. aeruginosa from horses and demonstrated that ERIC RAPD PCR is a rapid method for the examination of this species in horses, which may be useful in outbreak analysis.  相似文献   

Molecular diagnosis of Marteilia sydneyi (Paramyxea) in Sydney rock oysters, Saccostrea commercialis (Angas)     

T. J. ANDERSON  R. D. ADLARD  R. J. G. LESTER 《Journal of fish diseases》1995,18(6):507-510

Abstract. To prepare a diagnostic test, the polymerase chain reaction (PCR) with universal primers was used to amplify the internal transcribed spacer 1 (ITS1) of Marteilia sydneyi rDNA. A radiolabelled probe for M. sydneyi comprising putative ITS1 rDNA gave a strong signal for genomic DNA from M. sydneyi and no signal for host genomic DNA in Southern blots. A PCR to detect M. sydneyi used a forward primer designed from an internal site within the sequenced region and a reverse universal primer. It amplified a 650-bp fragment of M. sydneyi DNA when a combination of host and parasite DNA, extracted from an infected oyster, was used as the template.  相似文献   

Early Development and Putative Primordial Germ Cells Characterization in Dogs     

DS Martins  CE Ambrósio  NZ Saraiva  CV Wenceslau  AC Morini  I Kerkis  JM Garcia  MA Miglino 《Reproduction in domestic animals》2011,46(1):e62-e66

Previously, three distinct populations of putative primordial germ cells (PGCs), namely gonocytes, intermediate cells and pre‐spermatogonia, have been described in the human foetal testis. According to our knowledge, these PGCs have not been studied in any other species. The aim of our study was to identify similar PGC populations in canine embryos. First, we develop a protocol for canine embryo isolation. Following our protocol, 15 canine embryos at 21–25 days of pregnancy were isolated by ovaryhysterectomy surgery. Our data indicate that dramatic changes occur in canine embryo development and PGCs specification between 21 to 25 days of gestation. At that moment, only two PGC populations with distinct morphology can be identified by histological analyses. Cell population 1 presented round nuclei with prominent nucleolus and a high nuclear to cytoplasm ratio, showing gonocyte morphology. Cell population 2 was often localized at the periphery of the testicular cords and presented typical features of PGC. Both germ cell populations were positively immunostained with anti‐human OCT‐4 antibody. However, at day 25, all cells of population 1 reacted positively with OCT‐4, whereas in population 2, fewer cells were positive for this marker. These two PGCs populations present morphological features similar to gonocytes and intermediate cells from human foetal testis. It is expected that a population of pre‐spermatogonia would be observed at later stages of canine foetus development. We also showed that anti‐human OCT‐4 antibody can be useful to identify canine PGC in vivo.  相似文献