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1.
Deborah S. Greco Rod A.W. Rosychuk Gregory K. Ogilvie Lynn M. Harpold Camilla H. Van Liew 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》1998,12(1):7-10
Thirty adult, client-owned dogs were diagnosed with hypothyroidism based on history, physical examination findings, hematologic and biochemical abnormalities, thyrotropin (TSH) response testing, endogenous canine thyrotropin (cTSH) concentration, or both, and total serum thryoxine concentration. All dogs received levothyroxine (L-thyroxine) at an initial dose of 22 μg/kg PO sid in either a tablet (13 dogs) or chewable form (17 dogs). Energy expenditure of each dog during apparent rest was estimated with an open-flow indirect calorimetry system by determining the rates of carbon dioxide production and oxygen consumption. Energy expenditure of apparent rest (EE) was lower in untreated hypothyroid dogs compared with reference values for EE. After treatment with L-thyroxine, EE of the hypothyroid dogs was significantly ( P < .05) higher than pretreatment values. 相似文献
2.
Crown rot, caused by the fungus Fusarium pseudograminearum (teleomorph Gibberella coronicola) is a major disease of wheat in the Australian grain belt. However, there is little information available on the population structure of this pathogen. We measured genetic diversity as assessed with amplified fragment length polymorphism (AFLP) analysis within and between populations of F. pseudograminearum from northeastern, south central, and southwestern regions of the Australian grain belt. Amongst the 217 isolates, 176 haplotypes were identified and grouped into two main clusters. One cluster contained isolates from populations in northeastern Australia, and the other cluster contained isolates from populations in south central and southwestern Australia. The southern populations were distinguished from the northeastern populations by higher levels of population differentiation (Gst) between them and genetic identity amongst the regional populations. We hypothesize that the F. pseudograminearum populations from northeastern and southern Australia are independent, which could result from different founding events or from geographic isolation and the accumulation of genetic differences due to genetic drift and/or selection. 相似文献
3.
Limited morphological,physiological and genetic diversity of Phytophthora palmivora from cocoa in Papua New Guinea 
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下载免费PDF全文 In Papua New Guinea (PNG) cocoa (Theobroma cacao) is one of the most important cash crops grown in the tropical lowland and island regions. As in most cocoa‐growing areas, phytophthora black pod and canker cause significant yield losses. Cocoa breeding activities in PNG are focused in East New Britain province where disease control recommendations are also developed. This study tested the hypothesis that there was no diversity in the Phytophthora palmivora population causing black pod on cocoa by characterizing the variation in pathogen populations within and between the five major cocoa‐growing areas. Diseased pods were sampled hierarchically from the five locations and additional isolates were collected from soil, stem and leaf lesions, or retrieved from culture collections. Morphological characters showed continuous variation within the range described for P. palmivora. Genetic analysis revealed that the isolates belonged to one dominant clonal lineage, with restricted distributions of several other subpopulations. Lowest diversities were found in the geographically isolated Karkar Island and East Sepik province. Soil isolates showed greater genetic diversity than isolates from cocoa lesions. Intra‐farm variation was as much as inter‐farm or inter‐province variation. Both mating types were detected, although no strong evidence of sexual recombination was observed. The analysis revealed limited geographic, temporal or host specialization, suggesting continuous selection for pathogenicity from a genetic pool of P. palmivora. These findings have significant implications on the deployment of cocoa genotypes, enforcement of inter‐province quarantine and sustainable disease management strategies. 相似文献
4.
Fusarium oxysporum f. sp. radicis‐vanillae is the causal agent of root and stem rot of vanilla 下载免费PDF全文
下载免费PDF全文 S. Koyyappurath T. Atuahiva R. Le Guen H. Batina S. Le Squin N. Gautheron V. Edel Hermann J. Peribe M. Jahiel C. Steinberg E. C. Y. Liew C. Alabouvette P. Besse M. Dron I. Sache V. Laval M. Grisoni 《Plant pathology》2016,65(4):612-625
Root and stem rot (RSR) is a very detrimental disease of vanilla worldwide. Fusarium oxysporum is frequently associated with the disease but other Fusarium species are also reported. In this international study, 52 vanilla plots were surveyed in three of the most important vanilla producing countries (Madagascar, Reunion Island and French Polynesia) in order to determine the aetiology of RSR disease. Subsets from the 377 single‐spored Fusarium isolates recovered from rotten roots and stems in the surveys were characterized by molecular genotyping (EF1α and IGS gene sequences) and pathogenicity assays on Vanilla planifolia and V. ×tahitensis, the two commercially grown vanilla species. Fusarium oxysporum was shown to be the principal species responsible for the disease, representing 79% of the isolates recovered from the RSR tissues, 40% of which induced severe symptoms on inoculated plantlets. Fusarium oxysporum isolates were highly polyphyletic regardless of geographic origin or pathogenicity. Fusarium solani, found in 15% of the samples and inducing only mild symptoms on plantlets, was considered a secondary pathogen of vanilla. Three additional Fusarium species were occasionally isolated in the study (F. proliferatum, F. concentricum and F. mangiferae) but were nonpathogenic. Histopathological preparations observed in wide field and multiphoton microscopy showed that F. oxysporum penetrated the root hair region of roots, then invaded the cortical cells where it induced necrosis in both V. planifolia and V. ×tahitensis. The hyphae never invaded the root vascular system up to 9 days post‐inoculation. As a whole, the data demonstrated that RSR of vanilla is present worldwide and that its causal agent should be named F. oxysporum f. sp. radicis‐vanillae. 相似文献
5.
Perennial weeds are often controlled by mechanical means, which aim at stimulating axillary and adventitious buds to sprout. This happens when the apical dominance of the main shoot is removed by defoliation or when the underground system is fragmented. By repeating the measures, the result is a depletion of storage compounds, which weakens the plants and reduces their capacity to grow and reproduce. However, timing is critical. Earlier research has indicated that emergence from fragments of Sonchus arvensis cease during a period in autumn, while the seasonal pattern of sprouting in Cirsium arvense appears to be inconsistent. We studied the emergence pattern of defoliated plants with undisturbed root systems, from late summer to early spring. Potted plants grown outdoors were exhumed at regular intervals, put under forcing conditions for 4 weeks, after which shoots above and below soil level were counted and weighed together with the remaining root systems. In both species, the number and weight of emerged shoots decreased during a period in the autumn. In C. arvense, underground shoots were constantly produced during the same period, while fewer underground shoots were present in S. arvensis. For the latter species, apical dominance does not fully explain the effect; thus, endodormancy might be involved. Root weight increased until withering and did not explain the lack of emergence. Our results suggest an impaired sprouting capacity of undisturbed root systems of C. arvense and S. arvensis during September–October, which has implications for the timing and method of control of these species. 相似文献
6.
Yeong Yik Sung Hon Jung Liew Abol Munafi Ambok Bolong Mohd. Effendy Abdul Wahid Thomas H MacRae 《Aquaculture Research》2014,45(10):1706-1712
Exposure to heat‐shock protein (Hsp) stimulating factors induces Hsp accumulation and confers tolerance to lethal ammonia stress on the common carp Cyprinus carpio. This study investigated whether a non‐lethal heat shock bestowed similar protective effects against ammonia and induced thermotolerance, both thought to be rendered by increased amounts of Hsps. The 30‐min lethal temperature (30 min LHT) and 1‐h lethal ammonia concentration (1 h LCT) for this species occurred at 41°C and 14.2 mg/L NH3 respectively. Heating juvenile carp (5 cm) from 28°C to 32, 34 and 38°C, with a subsequent 8‐h recovery period augmented tolerance to lethal heat and ammonia perturbation by two to threefold as compared with animals held at 28°C. Protection occurred in conjunction with Hsp70 accumulation in gills, substantiating the role of this Hsp in enhancing the stress tolerance of common carp. 相似文献
7.
Vanilla stem rot, caused by Fusarium oxysporum f. sp. vanillae (Fov), is the main constraint to increasing vanilla production in the major vanilla‐producing countries, including Indonesia. The current study investigated the origin of Fov in Indonesia using a multigene phylogenetic approach. Nineteen Fov isolates were selected to represent Indonesia, the Comoros, Mexico and Réunion Island. The translation elongation factor 1 alpha gene and the mitochondrial small subunit ribosomal RNA gene phylogenies resolved the Fov isolates into three distinct clades in both phylogenetic species of the F. oxysporum species complex, indicating a polyphyletic pattern of evolution. In addition, Fov isolates from Indonesia were also polyphyletic. These results suggest that the vanilla stem rot pathogen in Indonesia has a complex origin. The implications for disease management are discussed. 相似文献
8.
The three rhizomatous perennials Elytrigia repens, Equisetum arvense and Tussilago farfara are all problematic in Scandinavian agriculture, due to their low susceptibility to soil cultivation. While repeated soil tillage is a fundamental part of the integrated control of these species, it is highly energy consuming and inefficient during periods when little sprout regrowth occurs. Substituting cultivation with mowing will reduce the environmental impact and labour costs, but its efficiency will still depend on the capacity of plants to sprout. Therefore, we studied the seasonal pattern in emergence and rhizome biomass allocation from July to April in six populations for each of the species. Plants were grown outdoors in pots buried in soil and exhumed at regular intervals in a two‐year experiment. In all three species, biomass allocation to rhizomes continued until late in the autumn. Emergence was severely impaired in E. arvense and T. farfara in September–October, while in E. repens, there was no such reduction in the number of emerged shoots. However, in the latter species, the shoot/rhizome ratio decreased and remained low until the plants had been exposed to a period of low temperatures. The increase in shoot/rhizome ratio for E. repens coincided with the resumed capacity to emerge for E. arvense and T. farfara. These results imply that there is no need to repeat a defoliation of E. arvense and T. farfara, if carried out in September–October. However, removal of the aerial plant parts early in the autumn is important to interrupt the upload of storage compounds to the rhizome systems of all species. 相似文献
9.
In this study, we investigated the extent of peatland degradation and development in Peninsular Malaysia and in the islands of Sumatra and Borneo, in the western part of insular Southeast Asia, since 1990. Furthermore, carbon emissions caused by these land cover changes were estimated in order to evaluate their contribution to global climate change. High resolution Landsat (30 m spatial resolution) and Satellite Pour l'Observation de la Terre (SPOT; 10–20 m) satellite images were used to derive information on land cover in 1990 and 2008. Analysis of land cover changes since 1990 revealed remarkable reduction and degradation of peatswamp forest ecosystems. In less than 20 years, 5·1 Mha of the total 15·5 Mha of peatland had been deforested (11·6 Mha → 6·5 Mha; 75 per cent → 42 per cent) and the great majority of the remaining forests had been selectively logged. Simultaneously, area covered by unmanaged secondary growth ecosystems had doubled to nearly a quarter of all peatlands and industrial plantations had expanded dramatically (0·3 Mha → 2·3 Mha; 2 per cent → 15 per cent). It was conservatively estimated that these changes have caused minimum of 1·5 Gt carbon emissions into the atmosphere since 1990. Currently, peatlands of the study area emit at least 81 Mt of carbon (equivalent to 300 Mt of carbon dioxide) on annual basis due to mere peat decomposition. Thereby, it was concluded that peatland degradation and development in insular Southeast Asia during the past two decades have not only put the existence of Southeast Asian peatswamp forest ecosystems in danger but it has also caused globally significant carbon emissions and created a constant source of carbon dioxide. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
10.
Qi L Heredia JE Altarejos JY Screaton R Goebel N Niessen S Macleod IX Liew CW Kulkarni RN Bain J Newgard C Nelson M Evans RM Yates J Montminy M 《Science (New York, N.Y.)》2006,312(5781):1763-1766
During fasting, increased concentrations of circulating catecholamines promote the mobilization of lipid stores from adipose tissue in part by phosphorylating and inactivating acetyl-coenzyme A carboxylase (ACC), the rate-limiting enzyme in fatty acid synthesis. Here, we describe a parallel pathway, in which the pseudokinase Tribbles 3 (TRB3), whose abundance is increased during fasting, stimulates lipolysis by triggering the degradation of ACC in adipose tissue. TRB3 promoted ACC ubiquitination through an association with the E3 ubiquitin ligase constitutive photomorphogenic protein 1 (COP1). Indeed, adipocytes deficient in TRB3 accumulated larger amounts of ACC protein than did wild-type cells. Because transgenic mice expressing TRB3 in adipose tissue are protected from diet-induced obesity due to enhanced fatty acid oxidation, these results demonstrate how phosphorylation and ubiquitination pathways converge on a key regulator of lipid metabolism to maintain energy homeostasis. 相似文献