Adherence of Actinobacillus pleuropneumoniae serotype 1 to swine buccal epithelial cells involves fibronectin          下载免费PDF全文

Roberto Hamer-Barrera  Delfino Godínez  V. Idalia Enríquez  Sergio Vaca-Pacheco  Rodrigo Martínez-Zú?iga  Patricia Talamás-Rohana  Francisco Suárez-Güemez    Mireya de la Garza 《Canadian journal of veterinary research》2004,68(1):33-41

The swine pathogen Actinobacillus pleuropneumoniae serotype 1 was investigated for its ability to adhere to swine, rat, and human buccal epithelial cells (BEC). The highest number of bacteria adhered was to swine BEC. This binding ability was affected by heating, extreme pH, treatment with sodium dodecyl sulfate, ethylenediamine tetraacetate, or periodate, and proteolysis, suggesting that cell-surface glycoproteins participate in adherence and that adherence is based mostly on ionic interactions. Mannose and swine fibronectin may play a direct role in this interaction. Convalescent-phase serum from naturally infected pigs inhibited the adhesion. There was a correlation between bacterial pathogenicity as well as host specificity and the capacity for adherence to swine BEC. Adhesion to swine BEC provides a convenient method to study in vitro the adherence of A. pleuropneumoniae and other pathogens of the pig respiratory tract.  相似文献   

Aboveground biomass,transpiration and water use efficiency in eucalypt plantation fertilized with KCl,NaCl and phonolite rock powder     

de Toledo  Fábio Henrique S. F.  de Moraes Gonçalves  José Leonardo  Mariño  Yesid Alejandro  de Vicente Ferraz  Alexandre  de Oliveira Ferreira  Eric Victor  Moreira  Gabriela Gonçalves  Hakamada  Rodrigo  de Arthur Júnior  José Carlos 《New Forests》2020,51(3):469-488

Potassium has important physiological functions in eucalypt plantations, increasing their productivity when applied to soil via mineral fertilizers. There is interest in identifying alternative sources to KCl owing to its high cost and limited reserves. The aim of the study was to test the effect of replacing KCl with NaCl and phonolite rock powder. Two comparisons were made: (1) application of 283 kg ha^?1 of KCl compared with that of 2125 kg ha^?1 of phonolite rock powder (equivalent to 170 kg ha^?1 of K₂O in both treatments); (2) application of 139 kg ha^?1 of NaCl compared with that of 183 kg ha^?1 of KCl (equivalent to 2.33 kmol Na and K, respectively). Radial growth, soil water content, leaf water potential (Ψ), accumulated transpiration, stem volume and biomass increment, as well as water use efficiency (WUE) were evaluated. In the first comparison, both fertilizations presented equal values for all characteristics evaluated. In the second, the accumulated transpiration in trees fertilized with KCl was 17% higher than that in plants fertilized with NaCl. In contrast, the WUE was 20% higher in the trees fertilized with NaCl than in those fertilized with KCl, reflecting the lower water consumption for the same increment in stem volume and biomass. We conclude that phonolite rock powder and NaCl are possible substitutes for conventional K fertilization performed with KCl.

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Soil CO2 emission in sugarcane management systems     

Rose Luiza Moraes Tavares  Zigomar Menezes de Souza  Diego Silva Siqueira  Newton La Scala Júnior  Alan Rodrigo Panosso 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(8):755-762

Sugarcane management systems affect soil attributes such as the carbon cycle. This fact has stimulated the sugar and alcohol industry to refine the sugarcane production systems by replacing the pre-harvest burning (PB) and manual harvest with mechanized harvesting followed by residue deposition. The aim of this study was to evaluate different management systems with respect to C cycling carbon dioxide and soil parameters (chemical, physical and biological) which were determined over the season. Three sugarcane cultivation systems were evaluated at the following periods: (a) PB, (b) 5-year green harvest and (c) 10-year green harvest. The results indicated that CO₂ emission was 36% greater in the 10-year sugarcane green harvest system than in the PB system. The bulk density and macroporosity were the factors that were most affected by the different sugarcane management systems and that significantly influenced soil CO₂ emissions. The principal component analysis showed that soil CO₂ emission was 18% influenced by base saturation (V%) and 14% by pH, especially in the PB area. Additionally, 19% was affected by carbon and macroporosity in the 5- and 10-year green harvest areas, respectively. From our results, it can be concluded that the most CO₂ emissions are in the areas of sugarcane green, this is due to the higher carbon concentration when compared with the area of burning sugarcane. The parameters that most influenced the CO₂ emissions were bulk density, porosity, macroporosity, pH and V%.  相似文献   

Effects of vaccination against brucellosis and clostridia on the intake,performance, feeding behavior,blood parameters,and immune responses of dairy heifers calves     

Hilton C Diniz Neto  Mayara C Lombardi  Mariana M Campos  Andrey P Lage  Rodrigo O S Silva  Elaine Maria Seles Dorneles  Camila Flvia A Lage  Wanessa A Carvalho  Fernanda S Machado  Luiz Gustavo R Pereira  Thierry R Tomich  Carolina P Ramos  Ronnie A Assis  Francisco Carlos F Lobato  Jordana A Santana  Ethiene Luiza S Santos  Rafaella S Andrade  Sandra G Coelho 《Journal of animal science》2021,99(5)

The aim of this study was to identify possible effects of different vaccination strategies (concomitantly or not) against brucellosis and clostridia on intake, performance, feeding behavior, blood parameters, and immune responses of dairy heifers calves. Fifty heifers calves were enrolled [38 Gyr (Zebu, Bos taurus indicus) and 12 5/8 Holstein Gyr]. At 120 d of age, animals were randomly distributed among 3 groups: B (n = 18), vaccinated against brucellosis; C (n = 14), vaccinated against clostridia and CB (n = 18), vaccinated concomitantly for both. Rectal and thermographic temperatures were evaluated on days 1, 0, 1, 2, 3, 5, 7,10, 14, and 28 relatives to the vaccination day. Feed and water intake, body weight (BW), and feeding behavior were monitored daily by an electronic feeding system. Blood was sampled on days 0, 3, 7, 14, and 28, relative to the vaccination day for determination of glucose and -hydroxybutyrate (BHBA) concentrations. Blood sampled on day 0 (prevaccination) and on days 28 and 42 were used to evaluate the immune response against Brucella abortus and clostridia. There was an increase in rectal temperature between the first and the third day postvaccination in the 3 groups. The thermography revealed an increase of local temperature for 7 d on groups B and CB. Group C had increased local temperature for a longer period, lasting for up to 14 d. Dry mater intake was reduced for groups B and CB, but no alteration was observed for group C. No alterations regarding initial BW, final BW, average daily weight gain, and feed efficiency were observed. No differences were observed for the 3 vaccination groups for blood parameters throughout the evaluation period. The concomitant vaccination against brucellosis and clostridia led to lower neutralizing antibody titers against epsilon toxin of Clostridium perfringens and botulinum toxin type C of C. botulinum (C > CB > B). When cellular proliferation assay and serological tests to B. abortus were evaluated, no differences were observed between groups B and CB. The present results indicate that the concomitant vaccination against brucellosis and clostridia has no relevant impact on the intake, performance, and feeding behavior of dairy calves. However, the concomitant vaccination of vaccines against these 2 pathogens impacts animal immunity against clostridial infections.  相似文献   

Sperm subpopulations influence the pregnancy rates in cattle     

Myrian Megumy Tsunokawa Hidalgo  Ana Beatriz Marques de Almeida  Fábio Lucas Zito de Moraes  Rodrigo Yudi Palhaci Marubayashi  Fabiana Ferreira de Souza  Thales Ricardo Rigo Barreiros  Maria Isabel Mello Martins 《Reproduction in domestic animals》2021,56(8):1117-1127

This study aimed to study the characteristics and subpopulations of spermatozoa from bulls with low and high reproductive performance based on pregnancy rates. Based on historical records of pregnancy rate from four farms, 24 bulls were selected. Two groups were established, with low pregnancy rates (n = 12; LOW), including bulls that presented pregnancy rates <52.27% (33.33% to 51.81%); and a group with high pregnancy rates (n = 12; HIGH), with pregnancy rates >52.27% (52.27% to 69.64%), after fixed-time artificial insemination (FTAI). The thawed sperm straws were analysed to sperm kinetics, morphology, plasma membrane integrity and sperm subpopulations. The LOW group exhibited a higher proportion of static cells (p < .05). In contrast, the HIGH group showed greater percentages for membrane integrity and total and progressive motility, and cells with fast and medium velocity (p < .05). In the cluster procedures, four sperm subpopulations were established. The low-fertility bulls presented the highest percentage of subpopulation 2 (41.46%), characterized by slow and progressive spermatozoa. The high-fertility bulls exhibited the highest percentage of subpopulation 3 (37.17%), characterized by fast and nonlinear spermatozoa. Results from this study indicated that bulls with greater percentages of fast and nonlinear spermatozoa seem to have greater fertilization capacity and the subpopulations analysis can be considered a tool to identify ejaculates with high fertility.  相似文献   

A logistic analysis of the factors determining the decision of smallholder farmers to intercrop: A case study involving rubber–tea intercropping in Sri Lanka     

S.M.M. Iqbal  C.R. Ireland  V.H.L. Rodrigo 《Agricultural Systems》2006

The factors influencing the decision of smallholder farmers to adopt new farming technologies were studied with reference to rubber–tea intercropping in Sri Lanka. Rubber–tea intercropping has been recommended previously to rubber farmers as a means to improve productivity and income during the early pre-tapping phase of rubber growth. Although crop trials have shown that the two crops are agronomically compatible and potentially produce a combined economic yield superior to the yield of a sole crop grown on the same area of land, there is little evidence of widespread adoption of this practice among smallholder farmers in Sri Lanka. The aim of the study was to determine the major factors that influence the decision to undertake rubber–tea intercropping and to construct a predictive model that describes the likelihood of adoption of intercropping by traditional smallholder rubber growers. A rapid rural appraisal (RRA) was undertaken based on semi-structured interviews of 90 smallholder farmers in the main rubber growing low wet zone of Sri Lanka. Among a number of factors shown to significantly influence the decision to intercrop tea with rubber, three were shown to operate independently, namely level of income, source of income (i.e. solely from own farm or from farm plus additional off-farm enterprises), and availability of land considered suitable for tea cultivation. A statistical model developed through correlation and logistic analysis, which predicts the likelihood of a smallholder adopting intercropping based on these factors, is presented and discussed. The most likely combination of circumstances (82% probability) under which rubber–tea intercropping is practiced is shown to be where the farmer’s income is greater than Rs. 10,000 per month, where the farmer’s income is based solely on own farm enterprises, and where more than 80% of the farmer’s land area was judged to be suitable for tea cultivation. Conversely, 30% of smallholder farmers that chose not to intercrop did possess land suitable for tea cultivation. Qualitative responses to the RRA indicated that limitation of technical knowledge was the main problem subsequently faced by rubber farmers who had adopted rubber–tea intercropping. Results indicate that there is need for both income support through farm subsidies and further agricultural extension services, if rubber–tea intercropping is to be adopted more widely in Sri Lanka. The wider usefulness of the developed logistic model in determining the likelihood of adoption of intercropping by smallholder farmers is discussed.  相似文献   

Evaluation of Natural Chemical Compounds Against Root-lesion and Root-knot Nematodes and Side-effects on the Infectivity of Arbuscular Mycorrhizal Fungi   总被引：1，自引：0，他引：1  

Cinta Calvet  Jorge Pinochet  Amèlia Camprubí  Victoria Estaún  Rodrigo Rodríguez-Kábana 《European journal of plant pathology / European Foundation for Plant Pathology》2001,107(6):601-605

The survival of two species of plant parasitic nematodes: the root-lesion nematode Pratylenchus brachyurus, and the root-knot nematode Meloidogyne javanica, was evaluated in saturated atmospheres of 12 natural chemical compounds. The infectivity of two isolates of arbuscular mycorrhizal fungi: Glomus mosseae and Glomus intraradices, under identical experimental conditions, was also determined. All the compounds tested exerted a highly significant control against M. javanica and among them, benzaldehyde, salicilaldehyde, borneol, p-anisaldehyde and cinnamaldehyde caused a mortality rate above 50% over P. brachyurus. The infectivity of G. intraradices was inhibited by cinnamaldehyde, salicilaldehyde, thymol, carvacrol, p-anisaldehyde, and benzaldehyde, while only cinnamaldehyde and thymol significantly inhibited mycorrhizal colonization by G. mosseae.  相似文献   

Inheritance pattern of chloroplast and mitochondrial genomes in artificial hybrids of Porphyra yezoensis (Rhodophyta)     

Sung-Je Choi  Eun-Jeong Park  Hirotoshi Endo  Yukihiro Kitade  Naotsune Saga 《Fisheries Science》2008,74(4):822-829

ABSTRACT:   To investigate inheritance of chloroplasts and mitochondria (organelles) in the marine red alga Porphyra yezoensis , cleaved amplified polymorphic sequence (CAPS) profiles of the two strains, TU-2 and KGJ, as parental gametophytes and 44 hybrid sporophytes (i.e. female of TU-2 and male of KGJ) were examined. A carbamyl phosphate synthase small subunit gene ( carA ) and ribosomal protein S11 gene ( rps11 )-small subunit ribosomal RNA gene ( rns ) spacer region were used as molecular markers for the chloroplast and mitochondrial DNAs, respectively. Thirty-eight of 44 (86.4%) conchocelis colonies showed maternal banding patterns, five (11.4%) colonies showed biparental bands and one (2.2%) colony showed paternal bands in CAPS analyses both with chloroplast and mitochondrial markers. These results suggest that organelles of P. yezoensis are inherited uniparentally from the female parent.  相似文献   

Growth,photosynthetic performance and shade adaptation of rubber (Hevea brasiliensis) grown in natural shade   总被引：3，自引：0，他引：3  

Senevirathna AM  Stirling CM  Rodrigo VH 《Tree physiology》2003,23(10):705-712

We compared growth, photosynthetic performance and shade adaptation of rubber (Hevea brasiliensis Muell. Arg.) plants growing in natural shade (33, 55 and 77% reduction in incoming radiation) to control plants growing in full sunlight. Stem diameter and plant height, measured over a 15-month period, were greatest in plants grown in full sunlight, and both parameters decreased with increasing shade. At 7 and 14 months after planting (MAP), total plant dry mass was highest in control plants and lowest in plants in 77% shade. Expansion of the fourth leaf whorl, monitored at 5-6 MAP, was slowest in plants in 77% shade and fastest in unshaded plants, which had more leaves and higher leaf areas and inter-whorl shoot lengths. In response to increasing shade, specific leaf area increased, whereas leaf weight ratio and relative growth rate decreased. Chlorophyll a/b ratio decreased with increasing shade, indicating shade-induced partitioning of chlorophyll into light-harvesting complexes. Compared to the response in unshaded plants, CO2 assimilation saturated at lower photosynthetic photon flux densities in plants in 77% shade, with a lower upper-asymptote to the light response curve. Chlorophyll fluorescence revealed no evidence of sustained photoinhibitory damage in unshaded plants. Dynamic photoinhibition decreased with increasing shade, with the greatest depression in the ratio of variable to maximal fluorescence around midday. We conclude that shade adaptation and shade-induced reductions in dynamic photoinhibition account for the enhanced early growth of rubber in light shade.  相似文献   

Lignin-degrading activity of edible mushroom <Emphasis Type="Italic">Strobilurus ohshimae</Emphasis> that forms fruiting bodies on buried sugi (<Emphasis Type="Italic">Cryptomeria japonica</Emphasis>) twigs     

Hiroto Homma  Hirofumi Shinoyama  Yukihiro Nobuta  Yoshie Terashima  Seigo Amachi  Takaaki Fujii 《Journal of Wood Science》2007,53(1):80-84

Strobilurus ohshimae is an edible mushroom, and it specifically forms its fruiting bodies on buried sugi (Cryptomeria japonica) twigs. In this research, we studied lignindegrading activity of S. ohshimae. We isolated 18 strains of S. ohshimae from various regions of Japan, and determined their lignin degradation rates on sugi wood meal medium. All the strains of S. ohshimae degraded approximately 6%–12% of sugi lignin in 30 days, and these lignin degradation rates were 1.5–3 times higher than those of Trametes versicolor, which is a typical lignin-degrading fungus. Among the three main lignin-degrading enzymes, activity of lignin peroxidase and manganese peroxidase was not observed, while 4340U/g of laccase was produced in 30 days. To investigate the effect of wood species on lignin degradation by S. ohshimae, the lignin degradation rate and laccase productivity on sugi wood meal medium were compared with those on beech (Fagus crenata). In T. versicolor, both lignin degradation rate and laccase productivity were higher on beech than on sugi. Conversely, in S. ohshimae, lignin degradation rate and laccase productivity were higher on sugi than on beech. Therefore, it was suggested that coniferous lignin is not always difficult to degrade for the fungi that inhabit softwood. Part of this article presented at the 54th Annual Meeting of the Japan Wood Research Society, Sapporo, August 2004  相似文献