Litter quality and decomposition of Vitis vinifera L. residues under organic and conventional farming systems     

Anna E. Nikolaidou  Athina K. Pavlatou-Ve  Sofia K. Kostopoulou  Andreas P. Mamolos  Kiriaki L. Kalburtji 《European Journal of Soil Biology》2010,46(3-4):208-217

In viticulture, residue decomposition may be important in terms of fertilization, due to the low grapevine nutritional demands. Grapevine residue quality, mass loss and nutrient release rates were studied in an organic (Vorg) and a conventional vineyard (Vconv) for 19-months. Leaf and cane residues of the Vorg (Lorg, Corg) and of Vconv (Lconv, Cconv) were buried in litterbags in both vineyards. Lorg contained in mg g^?1 526 C, 14.7 N, 1.2 P and 5.4 K; Lconv 509 C, 17.9 N, 1 P and 7.3 K; Corg 556 C, 5.7 N, 1.4 P and 6.9 K; Cconv 554 C, 7.6 N, 0.9 P and 7.7 K. Mean mass loss and N, P and K release rates (k′ = k × 10⁵) were higher in leaf (k′ = 543, 541, 448, 725) than in cane residues (k′ = 146, 90, 136, 494). In Vorg, mass loss and N, P and K release rates were higher in Lconv (k′ = 904, 748, 630, 1287) than in Lorg (k′ = 293, 357, 336, 502). For Lorg, mass loss and N release rates and for Corg mass loss rate were lower in Vorg (k′ = 293, 357, 102) than in Vconv (k′ = 537, 541, 218). For Lconv, mass loss and N and K release rates were lower in Vconv (k′ = 440, 518, 557) than in Vorg (k′ = 904, 748, 1287). Incorporation of plant residues in Vconv allowed reductions of nutrient applications of 25, 2 and 21 kg ha^?1 y^?1 of N, P and K, respectively; in Vorg nutrient applications reduced by 7, 1, 5.5 kg ha^?1 y^?1.  相似文献   

Biochemical characterisation of some non fermenting, non arginine hydrolysing mycoplasmas of ruminants     

Khan LA  Loria GR  Ramirez AS  Nicholas RA  Miles RJ  Fielder MD 《Veterinary microbiology》2005,109(1-2):129-134

The pattern and kinetics of substrate oxidation by type and recent field strains of Mycoplasma agalactiae, Mycoplasma bovis, Mycoplasma bovigenitalium and Mycoplasma ovine/caprine serogroup 11 were investigated by measurement of oxygen uptake. Metabolism of a range of organic acids, sugars and alcohols was detected. All the test strains were unable to oxidise sugars, glycerol and the organic acids, fumarate, malate and alpha-ketoglutarate (1 mM). All strains oxidised organic acid l-lactate, 2-oxobutyrate and pyruvate and demonstrated the ability to oxidise alcohols, particularly isopropanol, which was oxidised at a high rate and high affinity (0.5 mol/mol isopropanol). Its oxidation was consistent with acetone formation, which may be of important in relation to pathogenicity. All strains oxidised similar substrates, however differences were observed between strains in terms of the relative rates and kinetic values for some substrates.  相似文献   

Molecular characterization of Mycobacterium tuberculosis complex isolates from wild ungulates in south-central Spain     

Gortazar C  Vicente J  Samper S  Garrido JM  Fernández-De-Mera IG  Gavín P  Juste RA  Martín C  Acevedo P  De La Puente M  Höfle U 《Veterinary research》2005,36(1):43-52

The role of European wild ungulates in the epidemiology of tuberculosis (TB) is still under discussion. This study describes the geographical distribution and molecular typing of 77 Mycobacterium tuberculosis complex isolates belonging either to M. bovis or to M. caprae, cultivated from hunter harvested red deer (Cervus elaphus) and European wild boar (Sus scrofa) in 24 Spanish localities, and compares them with spoligotypes detected previously in humans, livestock or wild animals, as described in the literature. The distribution of the molecular type patterns suggests that the population of M. tuberculosis complex strains isolated from Spanish wild ungulates is spatially structured despite the lack of important geographical barriers and despite the increasingly frequent wildlife translocations. Red deer and the European wild boar can share the same molecular types in localities in which the M. tuberculosis complex was isolated from both species. Strains of bovine and caprine origin do circulate in the same local wildlife populations. Six out of 11 spoligotypes were similar to types described in human cases. The isolation of TB strains in fenced estates from wild animals that have not had contact with domestic livestock for at least the past two decades, strongly suggests that the M. tuberculosis complex is able to survive in these populations. Therefore, wildlife including cervids and the wild boar need to be considered in the epidemiology and control of tuberculosis.  相似文献   

Vegetative Compatibility and Mycotoxin Chemotypes among Fusarium graminearum (Gibberella zeae) Isolates from Wheat in Argentina     

Maria L. Ramirez  Maria M. Reynoso  Maria C. Farnochi  Sofia Chulze 《European journal of plant pathology / European Foundation for Plant Pathology》2006,115(2):139-148

Gibberella zeae (anamorph Fusarium graminearum) is the main pathogen causing Fusarium head blight of wheat in Argentina. The objective of this study was to determine the vegetative compatibility groups (VCGs) and mycotoxin production (deoxynivalenol, nivalenol and 3-acetyl deoxynivalenol) by F. graminearum populations isolated from wheat in Argentina. VCGs were determined among 70 strains of F. graminearum isolated from three localities in Argentina, using nitrate non-utilizing (nit) mutants. Out of 367 nit mutants generated, 41% utilized both nitrite and hypoxanthine (nit1), 45% utilized hypoxanthine but not nitrite (nit3), 9% utilized nitrite but not hypoxanthine (NitM) and 5% utilized all the nitrogen sources (crn). The complementations were done by pairing the mutants on nitrate medium. Fifty-five different VCGs were identified and the overall VCG diversity (number of VCGs/number of isolates) averaged over the three locations was 0.78. Forty-eight strains were incompatible with all others, thus each of these strains constituted a unique VCG. Twenty-two strains were compatible with other isolates and were grouped in seven multimembers VCGs. Considering each population separately, the VCG diversity was 0.84, 0.81 and 1.0 for San Antonio de Areco, Alberti and Marcos Juarez, respectively. Toxin analysis revealed that of the 70 strains of F. graminearum tested, only 90% produced deoxynivalenol, 10% were able to produce deoxynivalenol and very low amounts of 3-acetyldeoxynivalenol. No isolate produced nivalenol. The results indicate a high degree of VCG diversity in the F. graminearum populations from wheat in Argentina. This diversity should be considered when screening wheat germplasm for Fusarium head blight resistance.  相似文献   

Influence of dietary phospholipids on early ontogenesis of fish     

Chantal L Cahu  Enric Gisbert  Laure A N Villeneuve  Sofia Morais  Neila Hamza  Per-Avid Wold  & Jose L Zambonino Infante 《Aquaculture Research》2009,40(9):989-999

The aim of this paper is to provide explanations of how dietary phospholipid (PL) globally improves fish larval development, including growth and survival, digestive functions and skeletal development, and to propose optimal PL levels and sources in fish larval diets. Dietary incorporation of 8–12% PL related to dry matter (d.m.) promotes growth and enhanced survival in various species. Marine source PL, incorporating highly unsaturated fatty acids, was most efficient than soybean lecithin. This beneficial effect was explained by an enhancement in digestive functions, assessed by digestive enzyme activities and histomorphology. Nevertheless, 1.5–2.5% highly unsaturated fatty acids related to diet d.m. supplied by PL improved growth, survival and skeletal development, while 5% induced different skeletal deformities. The high incidence of deformities was associated with the down-regulation of genes involved in development, such as RXRα, RARα, RARβ and BMP-4, observed in the early stages in larvae fed a high highly unsaturated fatty acids level.  相似文献   

Gilthead seabream (Sparus aurata) response to three music stimuli (Mozart—“Eine Kleine Nachtmusik,” Anonymous—“Romanza,” Bach—“Violin Concerto No. 1”) and white noise under recirculating water conditions     

Sofronios E. Papoutsoglou  Nafsika Karakatsouli  Anna Psarrou  Sofia Apostolidou  Eustratios S. Papoutsoglou  Alkisti Batzina  Georgios Leondaritis  N. Sakellaridis 《Fish physiology and biochemistry》2015,41(1):219-232

  相似文献   

Salmonella isolated from individual reptiles and environmental samples from terraria in private households in Sweden     

Veronica O Wikstr?m  Lise-Lotte Fernstr?m  Lennart Melin  Sofia Boqvist 《Acta veterinaria Scandinavica》2014,56(1):7

Background

This study investigates Salmonella spp. isolated from privately kept reptiles and from environmental samples such as bedding materials or water from the floor of the enclosures (terraria). It also compares isolation of Salmonella using Modified Semisolid Rappaport-Vassiliadis (MSRV) medium or selective enrichment in Rappaport-Vassiliadis-Soya (RVS) pepton broth. Cloacal swabs or swabs from the cloacal area were collected from 63 individual reptiles belonging to 14 households. All reptiles were from different terraria and from 62 of these, environmental samples were also collected. Sampling were done by the reptile owners according to written instructions and sent by mail immediately after sampling. All but three samples were analyzed within 24 h after collection. Colonies suspected for Salmonella were tested for agglutination and serotyped using the White-Kauffmann-Le Minor scheme. The relative sensitivity (se) and specificity (sp) for MSRV compared with RVS, and the agreement coefficient kappa (κ) were calculated.

Results

Salmonella was isolated from 50/63 (80%) terraria, either from the reptiles (31/63; 49%) or from bedding material (39/62; 63%). The most common subspecies was Salmonella enterica subspecies enterica followed by S. enterica subspecies diarizonae. In reptiles, the most common S. enterica subspecies enterica serovars were Java (n = 4) and Fluntern (n = 4), compared with the serovars Tennessee (n = 10) and Fluntern (n = 10) in the environmental samples. The exact same set of Salmonella subspecies and serovars were not isolated from the individual reptiles and the environmental samples from any of the households. Isolation using MSRV yielded more Salmonella isolates 61/113 (54%) than enrichment in RVS 57/125 (46%). The se was 97.9% (95% Confidence Interval 93.9-100), the sp 78.5% (95% CI 68.5-88.5) and the κ 0.74, indicating substantial agreement between the tests.

Conclusions

Salmonella can be expected to be present in environments where reptiles are kept. This constitutes public health risks and should be considered during handling of the reptiles and during cleaning and disposal of bedding. A combination of different culturing techniques may be used to increase the isolation rate.  相似文献   

Rickettsia lusitaniae sp. nov. isolated from the soft tick Ornithodoros erraticus (Acarina: Argasidae)     

Natacha Milhano  Mariana Palma  Arlei Marcili  Maria Sofia Núncio  Isabel Lopes de Carvalho  Rita de Sousa 《Comparative immunology, microbiology and infectious diseases》2014

In this study a novel Rickettsia from the spotted fever group, isolated from Ornithodoros erraticus soft ticks collected from pigpens in the south of Portugal, is described. After initial screening revealed Rickettsia-positive ticks, isolation attempts were then performed. Successful isolates were achieved by shell-vial technique using Vero E6 cells at 28 °C. Molecular characterization of the isolate was performed based on analysis of five rickettsial genes gltA, ompA, ompB, sca1 and htr with their subsequent concatenation along with other rickettsial species resulting in a clustering of the new isolate with Rickettsia felis and Rickettsia hoogstraalii. The degree of nucleotide sequence similarity with other rickettsiae fulfills the criteria for classification of our isolate as a novel species. The name Rickettsia lusitaniae sp. nov. (= CEVDI PoTiRo) is proposed for this new species found in O. erraticus.  相似文献   

Validity tests of the mixing-length theory of deep convection     

Chan KL  Sofia S 《Science (New York, N.Y.)》1987,235(4787):465-467

The construction of solar or stellar models is hindered by the difficulty of computing, with sufficient accuracy, the convective fluxes in unstable regions. Although the mixing-length theory of convection has been used for more than three decades, its validity has neither been tested by experiment nor verified by computation. This report presents the results of a three-dimensional numerical simulation of deep and efficient convection that support two conclusions: (i) the basic picture proposed by the mixing-length theory is physically valid-the vertical correlation of the motion of fluid elements is proportional to the pressure scale height; and (ii) some dynamical variables, including the convective flux, can be approximately computed from the structure of the stratification with mixing-length approximations.  相似文献   

The shaping of modern human immune systems by multiregional admixture with archaic humans     

Abi-Rached L  Jobin MJ  Kulkarni S  McWhinnie A  Dalva K  Gragert L  Babrzadeh F  Gharizadeh B  Luo M  Plummer FA  Kimani J  Carrington M  Middleton D  Rajalingam R  Beksac M  Marsh SG  Maiers M  Guethlein LA  Tavoularis S  Little AM  Green RE  Norman PJ  Parham P 《Science (New York, N.Y.)》2011,334(6052):89-94

Whole genome comparisons identified introgression from archaic to modern humans. Our analysis of highly polymorphic human leukocyte antigen (HLA) class I, vital immune system components subject to strong balancing selection, shows how modern humans acquired the HLA-B*73 allele in west Asia through admixture with archaic humans called Denisovans, a likely sister group to the Neandertals. Virtual genotyping of Denisovan and Neandertal genomes identified archaic HLA haplotypes carrying functionally distinctive alleles that have introgressed into modern Eurasian and Oceanian populations. These alleles, of which several encode unique or strong ligands for natural killer cell receptors, now represent more than half the HLA alleles of modern Eurasians and also appear to have been later introduced into Africans. Thus, adaptive introgression of archaic alleles has significantly shaped modern human immune systems.  相似文献