An agglutination test for fast and specific detection of Erwinia psidii     

Claudia N. Montoya‐Estrada  Patrick F. Silva  Camila R. Costa  Leandro L. Oliveira  Lúcio M.S. Guimares  Jorge L. Badel  Acelino C. Alfenas 《Forest Pathology》2019,49(5)

Dieback and wilt, caused by Erwinia psidii (Ep), is one of the most important emergent diseases of Eucalyptus spp. in Brazil. Currently, pathogen detection relies on isolation of bacteria from infected plant tissue and either identification based on morphological, physiological and biochemical tests or DNA amplification using the polymerase chain reaction (PCR), which in many cases is laborious and cumbersome. Considering the need for a simpler and more rapid, yet reliable, method for detecting the pathogen, we obtained a polyclonal antibody (anti‐Ep) and developed an agglutination test for specific detection of E. psidii. The antiserum was produced against the E. psidii strain LPF534 and tested against 101 E. psidii isolates from Eucalyptus spp.; three E. psidii isolates from Psidium guajava; 23 Ralstonia solanacearum and 18 Xanthomonas axonopodis isolates pathogenic to Eucalyptus spp.; and seven endophytic isolates from Eucalyptus spp., three of which are phylogenetically related to the genus Erwinia. Results of direct ELISA indicated that a concentration as low as 3.5 µg/ml of the anti‐Ep antibody was able to detect the E. psidii antigen and that the antibody did not cross‐reacted with other bacteria pathogenic and non‐pathogenic to Eucalyptus spp. In the agglutination test, the anti‐Ep antibody showed positive reaction with all strains of E. psidii tested whereas cross‐reaction with none of the strains that belong to other taxonomic groups was observed. The agglutination test showed a detection limit of 10⁵ colony‐forming units (CFU)/ml, and its specificity was the same as that obtained by PCR amplification using E. psidii‐specific primers. These results demonstrate that the agglutination test developed here is a useful tool for specific, fast and inexpensive detection of E. psidii although only operational on pure bacterial suspensions and not yet directly from infected tissues.  相似文献   

Check dams and sediment control: final results of a case study in the upper Corneja River (Central Spain)     

Díaz-Gutiérrez  Virginia  Mongil-Manso  Jorge  Navarro-Hevia  Joaquín  Ramos-Díez  Iván 《Journal of Soils and Sediments》2019,19(1):451-466

Journal of Soils and Sediments - The sediment yield and erosion rate in an area can be estimated by calculating the volume of sediment retained by check dams. However, results can show unrealistic...  相似文献   

Dietary nitrogen and fish welfare     

Conceição LE  Aragão C  Dias J  Costas B  Terova G  Martins C  Tort L 《Fish physiology and biochemistry》2012,38(1):119-141

Little research has been done in optimizing the nitrogenous fraction of the fish diets in order to minimize welfare problems. The purpose of this review is to give an overview on how amino acid (AA) metabolism may be affected when fish are under stress and the possible effects on fish welfare when sub-optimal dietary nitrogen formulations are used to feed fish. In addition, it intends to evaluate the current possibilities, and future prospects, of using improved dietary nitrogen formulations to help fish coping with predictable stressful periods. Both metabolomic and genomic evidence show that stressful husbandry conditions affect AA metabolism in fish and may bring an increase in the requirement of indispensable AA. Supplementation in arginine and leucine, but also eventually in lysine, methionine, threonine and glutamine, may have an important role in enhancing the innate immune system. Tryptophan, as precursor for serotonin, modulates aggressive behaviour and feed intake in fish. Bioactive peptides may bring important advances in immunocompetence, disease control and other aspects of welfare of cultured fish. Fishmeal replacement may reduce immune competence, and the full nutritional potential of plant-protein ingredients is attained only after the removal or inactivation of some antinutritional factors. This review shows that AA metabolism is affected when fish are under stress, and this together with sub-optimal dietary nitrogen formulations may affect fish welfare. Furthermore, improved dietary nitrogen formulations may help fish coping with predictable stressful events.  相似文献   

Detection of the first lectin with antimicrobial activity present in serum of the Amazonian fish tambaqui Colossoma macropomum     

Elba Ver?nica Matoso Maciel Carvalho  Rosiely Félix Bezerra  Ranilson de Souza Bezerra  Janete Magali de Araújo  Athiê Jorge Guerra Santos  Maria Tereza dos Santos Correia  Luana Cassandra Breitenbach Barroso Coelho 《Fisheries Science》2012,78(4):879-887

Tambaqui Colossoma macropomum is the most important Amazonian native species in South American aquaculture. Innate immunity at least partially depends on the recognition of pathogen-associated molecular patterns by receptor-recognizing pathogens (PRRs). Some PRRs have been characterized in fishes, and several studies have focused on the role of lectins in the immune system of various fishes. Lectins are proteins that specifically recognize carbohydrates and which have important biological functions. Tambaqui serum lectin (ComaSeL), which was identified on the basis of its hemagglutinating activity, was pre-purified, biochemically characterized, and used in assays of antibacterial activity against pathogenic bacteria in freshwater fishes. A study of the seasonality of this lectin was performed. Comasel activity was stable at a pH between 4.0 and 9.0 and lost 100?% of its activity at 70?°C. It recognized the carbohydrates d-galactose, 1-O-methyl-d-galactopyranoside, and d-fucose, showing antibacterial activity for Gram-negative bacteria. Its activity showed significant differences between the summer and winter (p?<?0.05, Tukey test), thereby corroborating observations that tambaqui becomes more susceptible to mortality from diseases caused by bacteria and fungi during the winter. With this information, new tools may be developed for gaining a better understanding of the role of these proteins in the immune system of the tambaqui, ultimately resulting in the improved management of this fish by pisciculturists.  相似文献   

A recombinant form of chagasin from Trypanosoma cruzi: inhibitory activity on insect cysteine proteinases     

Dos Santos Monteiro AC  de Oliveira Neto OB  Del Sarto RP  de Magalhães MT  Lima JN  Lacerda AF  Oliveira RS  Scharfstein J  da Silva MC  Valencia JW  Jiménez AV  Grossi-de-Sa MF 《Pest management science》2008,64(7):755-760

BACKGROUND: The activity of the major digestive cysteine proteinase detected in the intestinal tract of larvae of the bean weevil, Acanthoscelides obtectus (Say), was efficiently inhibited by the well-characterized cysteine proteinase synthetic inhibitor E-64 and also by a recombinant form of chagasin (r-chagasin), a tight-binding cysteine proteinase inhibitor protein from Trypanosoma cruzi. RESULTS: Incorporation of r-chagasin into an artificial diet system at 0.1 g kg(-1) retarded growth rate, decreased larval survival and led to complete mortality of A. obtectus at the end of the trial. The observed differences in growth rates occurred particularly in the first and second development stages. Artificial seeds containing high levels of r-chagasin (0.5-30 g kg(-1)) completely inhibited larval penetration. CONCLUSION: Together, the results reported in this paper support the hypothesis that the inhibitory activity of r-chagasin towards the major insect gut cysteine proteinase in vitro and in vivo is an accurate prediction of its insecticidal effects. The selectivity of this inhibitor against insect digestive proteinases supports the key role in parasite virulence by affecting the endogenous proteinase activity in its natural host.  相似文献   

New genetic recombination in hypervariable regions of the white spot syndrome virus isolated from Litopenaeus vannamei (Boone) in northwest Mexico     

José Manuel Grijalva‐Chon  Jorge De la Rosa‐Vélez  Luis Manuel Enríquez‐Paredes 《Aquaculture Research》2012,43(3):339-348

The white spot syndrome virus (WSSV) is a pathogen of great concern to the worldwide shrimp culture. In comparative studies on the WSSV genome, regions such as the open reading frame (ORF) 14–15 and ORF 23–24, prone to deletions and recombination, had been useful to study the evolutive relationships among viral strains. When looking for the WSSV strains infecting Litopenaeus vannamei (Boone) in northwest Mexico, we found evidence of a genetic similarity in ORF 14–15 to a strain from India and a recombination involving ORFs 78, 79 and 80. Two genotypes were found involving the insertion of a 265 base‐pair segment of ORF 108 into ORF 78 with inversions and deletions within ORFs 78, 79 and 80. The WSSV has an Asian origin and the mutations found could be an adaptation strategy to infect L. vannamei and other crustacean species of the American continent.  相似文献   

Effect of supplemental phospholipase A2 antibody on the growth performance and selected immune criteria of rainbow trout (Oncorhynchus mykiss)     

Catarina Cruzeiro  Jorge Dias  António Afonso  Francisco Peixoto  Paulo Rema 《Aquaculture Research》2012,43(12):1900-1903

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Vermicompost enhances germination of the maritime pine (<Emphasis Type="Italic">Pinus pinaster</Emphasis> Ait.)     

Cristina Lazcano  Luís Sampedro  Rafael Zas  Jorge Domínguez 《New Forests》2010,39(3):387-400

We investigated the effect of vermicompost on the germination and early development of six different progenies of the maritime pine (Pinus pinaster Ait.). We compared the effects of incorporating solid vermicompost into the potting media to those of vermicompost water extract. The incorporation of vermicompost in the growing media of maritime pine increased germination by 16%, and particularly, addition of vermicompost water extract produced the best results. Plants germinated with vermicompost showed higher N content as compared to control plants, and this could have determined the faster maturation of the treated seedlings. Since the best effects on pine germination were observed after application of vermicompost water extract, other mechanisms, rather than the physical amelioration of the substrate, such as the presence of water soluble nutrients and organic compounds (i.e. humic acids and plant growth regulating substances) in the vermicompost, might be involved in the promotion of germination. We also report variation in the response of the different pine progenies to vermicompost application thereby confirming the necessity of taking into account genetic variability in order to study the potential of vermicompost and other biologically-active organic materials as a potting amendments.  相似文献   

Antituberculosis activity of natural and semisynthetic azorellane and mulinane diterpenoids     

Gloria María Molina-Salinas  Jorge Bórquez  Alejandro Ardiles  Salvador Said-Fernández  Luis Alberto Loyola  Aurelio San-Martín  Isidro González-Collado  Luis Manuel Peña-Rodríguez 《Fitoterapia》2010

The antituberculosis activity of 14 natural azorellane and mulinane diterpenoids isolated from Azorella compacta, Azorella madreporica, Mulinum crassifolium, and Laretia acaulis, together with eight semisynthetic derivatives, was evaluated against two Mycobacterium tuberculosis strains. The natural azorellanes azorellanol (3) and 17-acetoxy-13-α-hydroxyazorellane (6), and the semisynthetic mulinanes 13-hydroxy-mulin-11-en-20-oic-acid methyl ester (13) and mulinenic acid methyl ester (23), showed the strongest activity, with MIC values of 12.5 μg/mL against both strains. The methylated derivatives 13-hydroxy-mulin-11-en-20-oic-acid methyl ester (13), mulin-11,13-dien-20-oic acid methyl ester (15) and mulinenic acid methyl ester (23) proved to be more active than the parent compounds.  相似文献   

Estimation of banana (Musa sp.) plant transpiration using a standard 20 cm pan in a greenhouse   总被引：1，自引：0，他引：1  

Hai-Jun Liu  Shabtai Cohen  Josef Tanny  Jorge Hugo Lemcoff  GuanHua Huang 《Irrigation and Drainage Systems》2008,22(3-4):311-323

An experiment was carried out in a naturally ventilated greenhouse to study the relationship between banana (Musa sp.) plant transpiration (Tr) measured with load cells, reference crop evapotranspiration (ET_o) calculated with five widely used models (i.e. the Priestley-Taylor, FAO radiation, Hargreaves, FAO Penman and FAO Penman-Monteith models) and pan evaporation (E_pan) measured with a standard Chinese 20 cm pan. Microclimatic conditions were measured inside the greenhouse. Results show that vapor pressure deficit and air temperature had good linear correlations to banana Tr with R² of 0.67 and 0.62, respectively. Among the five models tested, banana Tr and ET_o calculated with the FAO-Penman model yielded the highest determination coefficient (R² = 0.67), followed by the FAO-PM model (R²=0.63), the FAO radiation model (R²=0.52), the Hargreaves model (R²=0.49) and the Priestley-Taylor model (R²=0.47). Banana transpiration Tr vs. E_pan yielded an R² of 0.83, which is higher than the five models tested. In conclusion, the 20 cm pan can be useful for estimating banana Tr in greenhouses.  相似文献