Treatment of a strandling whale (Kogia breviceps)     

Price MC  Macdonald GJ  Graham SL  Kirk EJ 《New Zealand veterinary journal》1984,32(3):31-33

A stranded young pygmy sperm whale was nursed for four days in a pool, fed an artificial diet via a stomach tube and injected intramuscularly with antibiotics and corticosteroids. Initially unable to maintain her balance or to swim, she showed progressive improvement and by the third day could swim and dive quite strongly. Early on the fifth day her condition rapidly worsened and she died. An autopsy revealed extensive deep bruising in the head and mid-abdominal regions consistent with injuries sustained during the stranding.  相似文献   

Death of a neonatal lamb due to Clostridium perfringens type B in New Zealand     

JS Munday  H Bentall  D Aberdein  M Navarro  FA Uzal  S Brown 《New Zealand veterinary journal》2020,68(4):242-246

ABSTRACT

Case history and clinical findings: A flock of 20 sheep was kept within three paddocks on a single property. None of the animals in the flock had been vaccinated against any disease for at least three years. Abdominal bloating and haemorrhagic diarrhoea were observed in Lamb 1 at 24 hours-of-age. The lamb subsequently died within an hour of the onset of clinical signs. Lamb 2 was 3-days-old when observed to be recumbent with opisthotonus. The lamb was treated with dextrose, vitamins B1 and B12, and penicillin G, but died 4 hours later.

Pathological findings: Examination of Lamb 1 revealed markedly increased gas within the peritoneum and within dilated loops of intestine. The intestines were dark red and contained large quantities of haemorrhagic fluid. Histology of the intestines revealed peracute mucosal necrosis with minimal accompanying inflammation. The intestinal lumen contained cell debris, haemorrhage, and myriad large Gram-positive bacilli. The intestines of Lamb 2 did not appear bloated or reddened. However, multiple fibrin clots were visible within the pericardial sac. Histopathological examination revealed small foci of necrosis within the mucosa of the distal intestine. The necrotic foci were often associated with large numbers of large Gram-positive bacilli.

Immunohistochemsitry and molecular biology: Intestinal samples from Lamb 1 were processed for Clostridium perfringens immunohistochemistry, which revealed large numbers of intralesional, positively immunostained rods. Fragments corresponding to the expected sizes for genes encoding alpha, beta, and epsilon C. perfringens typing toxins were amplified by PCR from DNA extracted from formalin-fixed sections of intestine.

Diagnosis: Lamb dysentery due to C. perfringens type B.

Clinical relevance: C. perfringens bacteria have a worldwide distribution, but disease due to C. perfringens type B has only been diagnosed in a small number of countries and has never been reported in New Zealand or Australia. C. perfringens type B produce both beta toxin and epsilon toxins, therefore both haemorrhagic enteritis and systemic vascular damage can develop. As many animals are exposed to C. perfringens without developing disease, there must be additional unknown factors that resulted in disease in these particular sheep. Vaccines that specifically protect against C. perfringens type B are available and may be recommended for use in smaller non-commercial flocks, as in the present case.  相似文献   

Soluble organic nitrogen in agricultural soils   总被引：36，自引：0，他引：36  

D. V. Murphy  A. J. Macdonald  E. A. Stockdale  K. W. T. Goulding  S. Fortune  J. L. Gaunt  P. R. Poulton  J. A. Wakefield  C. P. Webster  W. S. Wilmer 《Biology and Fertility of Soils》2000,30(5-6):374-387

 The existence of soluble organic forms of N in rain and drainage waters has been known for many years, but these have not been generally regarded as significant pools of N in agricultural soils. We review the size and function of both soluble organic N extracted from soils (SON) and dissolved organic N present in soil solution and drainage waters (DON) in arable agricultural soils. SON is of the same order of magnitude as mineral N and of equal size in many cases; 20–30 kg SON-N ha^–1 is present in a wide range of arable agricultural soils from England. Its dynamics are affected by mineralisation, immobilisation, leaching and plant uptake in the same way as those of mineral N, but its pool size is more constant than that of mineral N. DON can be sampled from soil solution using suction cups and collected in drainage waters. Significant amounts of DON are leached, but this comprises only about one-tenth of the SON extracted from the same soil. Leached DON may take with it nutrients, chelated or complexed metals and pesticides. SON/DON is clearly an important pool in N transformations and plant uptake, but there are still many gaps in our understanding. Received: 10 June 1999  相似文献   

种间关系对中条山油松人工林天然更新及群落稳定性的影响          下载免费PDF全文

裴顺祥  法蕾  杜满义  郭嘉  辛学兵 《林业科学研究》2022,35(1):150-157

[目的]为了揭示种间关系对中条山油松人工林天然更新及群落稳定性的影响,为油松人工林经营管理提供理论依据.[方法]基于中条山油松人工林群落样地调查数据,分析油松人工林下主要植物的种间关联性、生态位重叠及群落稳定性,并在此基础上探讨种间关联和生态位理论在油松人工林天然更新障碍及群落稳定性形成机制中的作用.[结果]中条山油松...  相似文献   

Cytochemical demonstration of catabolism in soil micro-organisms     

R.M. Macdonald 《Soil biology & biochemistry》1980,12(4):419-423

Electron transport was demonstrated cytochemically in soil micro-organisms. After counterstaining, enzymically active and inactive cells were distinguishable. The number of active micro-organisms detected by this method ranged from ca. 11 — > 46% of the total microscopic count in several soils. The technique was also applied successfully to algae from soil crusts, micro-colonies of microorganisms removed intact from the surface of soil crumbs and to micro-organisms associated with plant roots.  相似文献   

An outbreak of botulism in gulls on the Firth of Forth,Scotland     

J.W. Macdonald  K.T. Standring 《Biological conservation》1978,14(2):149-155

The first recorded outbreak of type C botulism in gulls (Larus spp.) in Britain is described. Between June and October 1975, at least 2080 gulls died around the Firth of Forth. The hot dry summer favoured the proliferation of the causative organism, Clostridium botulinum. A definite source of the botulism was not found but prompt removal of the carcases and covering the pools where Cl. botulinum was growing appeared to reduce the mortality. Immunity acquired during widespread exposure to the disease in 1975 may have prevented the reappearance of botulism during the similar climatic conditions in 1976.  相似文献   

Effects of Azoxystrobin on Mycotoxin Production in a Carbendazim-Resistant Strain ofFusarium sporotrichioides     

J. P. Felix D’Mello  Ann M. C. Macdonald  Rosalie Rinna 《Phytoparasitica》2001,29(5):431-440

Carbendazim-resistant (RS) and control (CS) strains ofFusarium sporotrichioides Sherb., previously developed in our laboratory, were exposed to graded concentrations of azoxystrob in in broth media under shake-culture conditions for 2, 3, 4 and 8 days. Azoxystrobin concentrations were 0, 1, 10 and 100 mg 1^-1 broth and cultures were incubated at a constant 25°C. Mycelial growth was significantly affected by strain (P<0.01), azoxystrobin concentration (P<0.001) and incubation time (P<0.001). Combined results for the four incubation times showed that CS yielded higher mycelial mass than RS (P<0.01) only in the absence of azoxystrobin. At fungicide additions of 1, 10 and 100 mg P^-1 mycelial growth was reduced (P<0.001) with minimal strain differences (P>0.05) at all three doses of azoxystrobin. Significant (P<0.05 or better) strain-fungicide interactions were recorded in trichothecene production following exposure to azoxystrobin. At 4 and 8 days of incubation, the 10 mg 1^-1 addition of azoxystrobin stimulated T-2 toxin synthesis (P<0.05) only in RS cultures. In contrast, T-2 toxin enhancement in CS cultures occurred only on day 8 but at a lower level of azoxystrobin (1 mg1^-1). Thus, the stimulation of T-2 toxin synthesis depended upon strain and azoxystrobin level. Production of diocetoxyscirpenol (DAS) was affected by a more complex set of interactions. Overall means showed that, in comparison with initial values (on day 2 or 3), DAS output maximized significantly(P<0.05) on day 4 in RS cultures and on day 8 in CS. Marked strain effects were observed on exposure to the 10 mg 1^-1 level of azoxystrobin. At this level, DAS production was enhanced in RS only after 4 (P<0.01 ) and 8 (P<0.05) days of incubation, while in contrast, CS reduced DAS production. As with T-2 toxin, DAS production in CS was stimulated (P<0.05 or better) only at low exposure levels of azoxystrobin. In the case of neosolaniol (NEO), however, the main effect of strain was significant (P<0.05), with CS producing consistently more of the mycotoxin than RS on day 4 of the experiment. At this point, the NEO:T-2 toxin ratio was also higher in CS (0.63) than in RS (0.12), a feature reported by us previously. In conclusion, the present investigation has shown for the first time that the development of resistance to one fungicide can affect trichothecene production inF. sporotrichioides on exposure to a second fungicide. These results have been incorporated into a new classification scheme for fungicide efficacy which is also presented in this paper. http://www.phytoparasitica.org posting Oct. 7,2001.  相似文献   

Modeling shoot water contents in high-elevation Picea rubens during winter   总被引：1，自引：0，他引：1  

Boyce RL  Friedland AJ  Macdonald VN 《Tree physiology》1992,11(4):341-355

During the winter of 1990-1991, a meteorological tower was established at an 880-m elevation site within the spruce-fir zone on Mt. Moosilauke, New Hampshire, USA. Hourly means of air, needle and trunk temperatures, wind velocity, relative humidity and solar radiation were recorded. On a weekly basis, shoots that had elongated during the preceding growing season were collected from four red spruce (Picea rubens Sarg.) trees and their relative water contents (RWC) determined. Cuticular resistances of needles from these shoots were measured four times during the winter.Measured meteorological parameters were used in a previously developed model to simulate changes in red spruce shoot RWC during the winter. The modeled results were compared to measured shoot RWCs. The predictive power of the model was improved when it was modified to include measured values of cuticular resistance and needle and trunk temperatures. The new version of the model accurately predicted RWC from late December 1990 to the beginning of April 1991, after which spring recharge appeared to occur. We conclude that water lost from foliage was easily replaced by stored reserves and that uptake of water by the roots was not required to maintain an adequate foliar water content during the winter.  相似文献   

Understory plant communities of boreal mixedwood forests in western Canada: Natural patterns and response to variable-retention harvesting     

S. Ellen Macdonald  Treena E. Fenniak 《Forest Ecology and Management》2007

We examined patterns of variation in richness, diversity, and composition of understory vascular plant communities in mixedwood boreal forests of varying composition (broadleaf, mixedwood, conifer) in Alberta, Canada, before and for 2 years following variable-retention harvesting (clearcut, 20 and 75% dispersed green tree retention, control). Broadleaf-dominated forests differed from mixedwood or conifer-dominated forests in that they had greater canopy cover, litter depth, soil nitrogen, warmer soils, as well as greater shrub cover, herb and shrub richness and diversity (plot scale). In contrast, conifer, and to a lesser extent mixedwood, forest had greater β diversity than broadleaf forest. Overall, mixedwood and conifer forests were similar to one another, both differed from broadleaf forest. Several species were found to be significant indicators of broadleaf forest but most of these also occurred in the other forest types. Understory composition was related to canopy composition and edaphic conditions. Variable-retention harvesting had little effect on understory cover, richness, or diversity but resulted in reduced richness and β diversity at a larger scale. The clearcut and 20% treatments affected composition in all forest types. Early successional species and those common in disturbed sites were indicators of harvesting while evergreen, shade-tolerant understory herbs were indicators of the control forest and 75% retention harvest. We conclude that it is important to maintain a range of variation in canopy composition of mixedwood forests in order to conserve the associated understory communities. The presence of conifers in these forests has a particularly important influence on understory communities. The threshold for a lifeboat effect of variable-retention harvesting is between 20 and 75% retention. Examination of richness and β diversity at a variety of scales can provide interesting information on effects of harvesting on spatial reorganization and homogenization of understory plant communities.  相似文献   

国有苗圃所有制结构调整之我见     

周国平  李发凯 《江西林业科技》2001,(Z1)

所有制结构的调整是国有苗圃发展壮大的出路所在.笔者从必要性,战略方向,基本途径等三个方面阐述了看法.  相似文献