Diversity of root-knot nematodes in Moroccan olive nurseries and orchards: does <Emphasis Type="Italic">Meloidogyne javanica</Emphasis> disperse according to invasion processes?     

Mohamed Aït Hamza  Nadine Ali  Johannes Tavoillot  Odile Fossati-Gaschignard  Hassan Boubaker  Abdelhamid El Mousadik  Thierry Mateille 《BMC ecology》2017,17(1):41

  相似文献   

饲用微生物的高密度培养     

谷春涛  彭爱铭  萨仁娜  佟建明 《猪业科学》2003,20(10):46-47

高密度培养(HCDC,highcelldensityculture)以其优越性在发酵生产上得到了广泛的应用。它能获得高的产率,降低生产成本,从而提高产品在市场上的竞争力。将高密度培养技术用于直接饲用微生物(DFM)的生产中,对于提高发酵水平,更好地满足市场需求,具有重要的意义。  相似文献   

The effects of agricultural fields and human settlements on the use of rivers by wildlife in the mid-Zambezi valley,Zimbabwe     

Fritz  Hervé  Saïd  Sonia  Renaud  Pierre-Cyril  Mutake  Snoden  Coid  Craig  Monicat  François 《Landscape Ecology》2003,18(3):293-302

After the eradication of the Tse-Tse fly in the Mid-Zambezi valley, human settlements and fields extended mainly along the main rivers. In order to investigate the consequences of this human development on wildlife diversity we monitored three rivers of the Mid-Zambezi valley in Zimbabwe: Angwa, Manyame and Kadzi. The rivers were divided in segments of 200 m which were checked for spoors in order to assess the number of species and the number of individuals that used the segments. Human settlements were also recorded. We used a GIS to define the spatial characteristics of the fields present along the rivers, and related them to the distribution and abundance of wild species spoors in the river beds and banks. Our results show that the number of species in one segment of the river decreased with the increasing size of the field area bordering the segment. For all the major ungulate species, the numbers of individuals recorded per segment decreased with increasing field area. A similar trend was observed for small and medium-sized carnivores, though they were in lower numbers when present. Our analyses thus confirm that the extension of human agriculture in wildlife areas has an impact on most wild species, but we also define some threshold value of field size above which there seem to be an acceleration of the decrease in wildlife density and diversity: 3.2 ha for medium and small herbivores and carnivores; only the elephant seem to tolerate larger field area with a threshold value of 32 ha.This revised version was published online in May 2005 with corrections to the Cover Date.  相似文献   

Study of Resistance to Orobanche ramosa in Host (Oilseed Rape and Carrot) and Non-host (Maize) Plants     

Naïma Zehhar  Pascal Labrousse  Marie-Claire Arnaud  Christian Boulet  Driss Bouya  André Fer 《European journal of plant pathology / European Foundation for Plant Pathology》2003,109(1):75-82

Orobanche ramosa is a parasitic Angiosperm responsible for severe yield losses in several economical crops. It is a serious threat in oilseed rape in France and Morocco and is appearing in carrot crops in Morocco. In this study, several varieties of oilseed rape and carrot were screened in order to identify resistant cultivars and to characterize the resistance mechanisms involved. All the 15 oilseed rape varieties tested were susceptible. In carrot, the varieties 'Colmar à coeur rouge' and 'Nantaise demi-longue' were susceptible, whereas 'Palaiseau' and 'Buror' were resistant. In the susceptible 'Colmar à coeur rouge' carrot no defence reactions were found and the development of the parasite inhibited carrot tap root formation. In the resistant carrot varieties, the parasite germinated, became attached to the host root but became necrotic before emergence. In 'Buror' carrot, formation of a mechanical barrier was associated with the restriction to the cortex of the parasite. In maize cv. 'Vigni', a non-host of O. ramosa, thickening of xylem vessels, cell divisions in the central cylinder and formation of an encapsulation layer were observed in association with restricted development of Orobanche haustoria.  相似文献   

High-throughput screening reveals small molecule modulators inhibitory to Acidovorax citrulli     

Yu Lu  Loïc Deblais  Gireesh Rajashekara  Sally A. Miller  Yorsa A. Helmy  Haijun Zhang  Ping Wu  Yanhong Qiu  Xiulan Xu 《Plant pathology》2020,69(5):818-826

Acidovorax citrulli is a seed-transmitted gram-negative bacterium that can cause substantial economic yield loss in watermelon and melon production worldwide. Four small-molecule libraries containing 4,952 compounds were selected for high-throughput screening against A. citrulli wild-type strain Xu3-14 by evaluation of growth inhibition. One hundred and twenty-seven molecules (2.5% hit rate) were identified as bactericidal or bacteriostatic against A. citrulli at 100 μM. Secondary screens indicated that 27 candidate compounds were more effective against A. citrulli Group II strains than Group I strains (classified using repetitive element PCR). Several compounds were inhibitory to other pathogenic bacteria, including Clavibacter michiganensis subsp. michiganensis and Xanthomonas campestris pv. campestris, but did not affect the growth of plant beneficial bacteria Pseudomonas fluorescens and Bacillus subtilis. More than half of the compounds did not inhibit germination of Arabidopsis or watermelon seeds. The effect of small molecules on A. citrulli seed-to-seedling transmission was evaluated by applying each compound to inoculated watermelon seeds and assessing seedling infection. Nine compounds were chosen for further investigation based on their reduction of percentage seedling infection and compiling scores on their specificity, sensitivity, and phytotoxicity obtained in the secondary screens. The five best compounds were selected (thiamphenicol, nadifloxacin, pipemidic acid, ciclopirox, and zinc pyrithione) for greenhouse tests and were found to effectively reduce the seed-to-seedling transmission of A. citrulli in both artificially and naturally infested seeds. These top five compounds provide a basis for future development of an A. citrulli-specific bactericide.  相似文献   

Composition and fatty acid profile of milk from cows supplemented with pressed oilseed cake          下载免费PDF全文

Ronaldo Lopes Oliveira  Severino Gonzaga Neto  Francisco Helton Sa de Lima  Ariosvaldo Nunes de Medeiros  Leilson Rocha Bezerra  Elzania Sales Pereira  Adriana Regina Bagaldo  Caius Barcellos de Pellegrini  Braulio Rocha Correia 《Animal Science Journal》2016,87(10):1225-1232

This study compared the productive and nutritional parameters of milk from crossbred lactating cows managed on Panicum maximum Jacq. cv. Tanzania and with a diet supplemented with different pressed oilseed cakes. The supplements used were as follows: peanut cake, sunflower cake and palm kernel cake for replacement of soybean meal. Sixteen cows with an average weight of 544 ± 57 kg and producing 8 ± 1.4 L of milk per day were used in this study. The animals were randomly assigned to the treatments according to a Latin square design repeated over time, with four treatments, 16 animals and four experimental periods. Supplementation of the diet with peanut cake, sunflower cake and palm kernel cake compared with soybean meal in the diet of cows did not affect the average daily production or composition of the milk. The palm kernel cake promoted an increase in lauric fatty acids (C_12:0) and palmitoleic acids (C_16:1) (5.02 and 1.65%, respectively) compared with peanut cake and sunflower cake (4.13 and 4.01%, respectively). The levels of oleic fatty acids (C_18:1) were higher for the sunflower cake and palm kernel cake supplements (26.01 and 25.01%, respectively) compared with peanut cake (23.11%). The replacement of soybean meal with sunflower cake and palm kernel cake improved the nutritional quality of the milk, with lower concentrations of saturated fatty acids and higher concentrations of unsaturated fatty acids, without compromising the production or nutritional composition of the milk. © 2015 Japanese Society of Animal Science  相似文献   

Skull size and shape variation in Psammomys spp. (Rodentia,Gerbillinae) from Tunisia,with emphasis on the impact of allometric variation on species recognition     

Hanene Khemiri  Paolo Colangelo  M’barek Chétoui  Saïd Nouira 《African Zoology》2016,51(3):145-152

In Tunisia both Psammomys obesus and P. vexillaris are found. These taxa have been the subject of taxonomic controversy for some time, due to variability in the classical morphological characters used for taxonomic recognition. In this study we investigated skull size and shape variation in the genus Psammomys by using geometric morphometrics to evaluate the extent of intra- and interspecific shape variation and explicitly tested for the impact of allometric shape variation on species discrimination. Eleven populations of the two species from 10 localities in Tunisia were studied. Statistical analyses of size and shape showed large size variation within P. obesus, but no shape differences were revealed among populations of this species. Interspecific analysis revealed that P. vexillaris had the smallest skull. Principal component analysis and Procrustes distances showed good discrimination between the two species after removal of the allometric component of shape variation. The results obtained show that allometric-related shape variation could mask discrimination between the two Psammomys species. This finding might explain the uncertainty in classification of these species in the past. The interspecific allometric-free phenotypic differences observed may be associated with adaptive processes linked to the different environmental and trophic preferences of the two species.  相似文献   

Effect of polyamines on intracellular calcium of the rat cardiomyocytes with anoxia and reoxygenation     

ZHAO Ya-jun  XU Chang-qing  SHI Sa  SUN Hong-li  WANG Ning  LI Bao-xin  WANG Ling  YANG Bao-feng  Rui Wang 《园艺学报》2005,21(10):1938-1941

AIM: To study the effect of extrogenous low concentration polyamine on cardiomyocyte calcium overload caused by anoxia and reoxygenation. METHODS: Enzymatically isolated rat ventricular myocytes were perfused with normal Tyrode solution for 8 min, then change to anoxia solution for 32 min, at last back to normal Tyrode solution perfusion for 8 min to establish the cardiomyocyte model of anoxia and reoxygenation. Spermine was added extracellularly to the bath before anoxia and spermine, spermidine or putrescine was added extracellularly after reoxygenation. Intracellular calcium fluorescence intensity (FI) was measured continuously by laser scan confocal microscope (LSCM). RESULTS: In the unstimulated state, exogenous spermine (1 mol/L) did not change resting ［Ca2+］i in the rat cardiomyocytes. Adding spermine before anoxia antagonized the ［Ca2+］i elevating caused by anoxia/reoxygenation. Adding spermine after reoxygenation also lowed the enhanced ［Ca2+］i caused by reoxygenation. Considering the potency of two conditions, the former was more efficacious than the later. Spermidine and putrescine also lowed the enhanced ［Ca2+］i caused by reoxygenation, but they were less efficacious than spermine. CONCLUSIONS: The results indicate that spermine given before anoxia or after reoxygenation, antagonized or lowed the cardiomyocytes calcium overload caused by anoxia/reoxygenation, but the later was weaker than the former. The order of potency of the polyamine lighten cardiomyocytes calcium overload caused by anoxia/reoxygenation was spermine>spermindine>putrescine.  相似文献   

The effects of cyclophosphamide and its uroprotective agents, mesna and hyperbaric oxygen, on urinary bladder motility in guinea pigs     

Sağmanligil V  Etlik O  Pişkin I  Tomur A 《Acta veterinaria Hungarica》1999,47(4):451-460

The aim of this research was to observe the effects of cyclophosphamide and its uroprotective agents, mesna and hyperbaric oxygen (HBO), on the motility of urinary bladder muscle in guinea pigs. In the experimental groups, mesna and cyclophosphamide were intraperitoneally injected at a dose of 21.5 mg/kg and 68.1 mg/kg, respectively. For the combination of mesna and cyclophosphamide, one dose of mesna was injected 20 min before cyclophosphamide administration and three additional injections of mesna were repeated every three hours. A total of 8 HBO exposures were performed at 2.8 ATA for 90 min twice daily for another experimental group. In the HBO and cyclophosphamide combined group 5 HBO exposures were given prophylactically before cyclophosphamide. The combination of mesna, HBO and cyclophosphamide was administered by the same procedure. The contractions obtained in response to acetylcholine (ACh, 10(-4) M) in the control group were reduced using cyclophosphamide and HBO individually, but not by mesna. However, the contractions belonging to the various combinations of these three agents were not different from those seen in the control group. On the other hand, the combinations of cyclophosphamide, mesna and HBO showed higher responses to ACh than the groups in which cyclophosphamide and HBO were used individually, while the responses elicited by the cyclophosphamide and HBO combination were greater than those seen in the group treated with HBO only.  相似文献   

Characterization of the Exoglucanase-Encoding Gene PaEXG2 and Study of Its Role in the Biocontrol Activity of Pichia anomala Strain K     

Grevesse C  Lepoivre P  Jijakli MH 《Phytopathology》2003,93(9):1145-1152

ABSTRACT The PaEXG2 gene, encoding an exo-beta-1,3-glucanase, was isolated from the biocontrol agent Pichia anomala strain K. PaEXG2 has the capacity for coding an acidic protein of 427 amino acids with a predicted molecular weight of 45.7 kDa, a calculated pI of 4.7, and one potential N-glycosylation site. PaEXG2 was disrupted by the insertion of the URA3 marker gene, encoding orotidine monophosphate decarboxylase in strain KU1, a uracil auxotroph derived from strain K. Strain KU1 showed inferior biocontrol activity and colonization of wounds on apples, compared to the prototrophic strain. Antagonism and colonization were recovered after the restoration of prototrophy by transformation with the URA3 gene. Integrative transformation was shown to be mostly ectopic in strain K descendants (only 4% of integration by homologous recombination). PaEXG2 disruption abolished all detectable extracellular exo-beta-1,3-glucanase activity in vitro and in situ but did not affect biocontrol of Botrytis cinerea on wounded apples.  相似文献