The role of feral mammals on wildlife infectious disease prevalence in two nature reserves within Mexico City limits.     

Gerardo Suzán  Gerardo Ceballos 《Journal of zoo and wildlife medicine》2005,36(3):479-484

Wild and feral medium-sized mammals were live trapped at two natural protected areas within the Mexico City limits to determine antibody prevalence for the most common infectious diseases (rabies, toxoplasmosis, and canine parvovirus) in dogs and cats. Mammals were trapped during the dry (March-April) and rainy seasons (July-August) of 1996 and 1997. A total of 68 individuals were captured, representing 8 species: opossums (Didelphis virginiana), ringtails (Bassariscus astutus), spotted skunks (Spilogale gracilis), weasels (Mustela frenata), rock squirrels (Spermophilus variegatus), Mexican gray squirrels (Sciurus aureogaster), feral cats (Felis catus), and feral dogs (Canis familiaris). There was marked seroprevalence for parvovirus (86.6%) and lower seroprevalences for both toxoplasma (23.9%) and rabies (17.9%). There were no significant prevalence differences among mammals in both protected areas, which were of contrasting size and isolation (i.e., small and isolated versus large and nonisolated). We suggest that high seroprevalence of these three infectious agents in wild mammals is a result of the high densities of feral dogs and cats in the two areas sampled. Feral dogs are able to maintain the infectious agents in these localities regardless of the protected area size and isolation. However, the native mammals of the small and isolated reserve are more vulnerable to infectious diseases because of small population size and genetic bottlenecks. Our results indicate that natural areas in and around Mexico City are a refugium for latent infectious agents, several of which are zoonotic. These findings suggest that conservation measures, such as eradication of feral mammals and vaccination programs, in the protected areas and surrounding areas could be beneficial.  相似文献   

Effects of deficit irrigation strategies on cluster microclimate for improving fruit composition of Moscatel field-grown grapevines   总被引：1，自引：0，他引：1  

Tiago Pedreira dos Santos  Carlos M. Lopes  M. Lucília Rodrigues  Claudia R. de Souza  Jorge M. Ricardo-da-Silva  João P. Maroco  João S. Pereira  M. Manuela Chaves 《Scientia Horticulturae》2007

The grapevine plays a very important role in the economic, social and cultural sectors of many regions; however vineyards are often grown in regions under stressful conditions and thus they are vulnerable to climate change. The objective of this research was to investigate the effect of partial root-zone drying (PRD) irrigation on vine water relations, vegetative growth, plant microclimate, berry composition and yield components, compared to conventional deficit irrigation (DI, 50% ETc), full irrigation (FI, 100% of ETc) and non-irrigated vines (NI). The study was undertaken in mature ‘Moscatel’ grapevines (Vitis vinifera L.) grown in Pegões, South of Portugal. Compared to the other irrigated treatments, PRD vines showed a better microclimate at the cluster zone with higher incident photosynthetic photon flux density (PPFD). Within the more open canopies of NI and PRD treatments, berry temperatures were higher than those of denser ones (DI and FI). Compared to the conventional irrigation technique the better microclimate observed in PRD vines was a consequence of a reduction in vine growth, where lower values of leaf layer number, leaf area, canopy wideness, water shoots and shoot weight were observed. In PRD vines we observed a tendency to a development of a deeper root system, while DI and FI showed a more homogeneous root distribution throughout the different soil layers. PRD showed an improvement in berry quality with higher values of flavour precursors, and total phenols concentration without any significant yield reduction compared to DI and FI.  相似文献   

Cacao leaf procyanidins increase locally and systemically in response to infection by Moniliophthora perniciosa basidiospores     

Fabio C. Chaves  Thomas J. Gianfagna   《Physiological and Molecular Plant Pathology》2007,70(4-6):174-179

Flavan-3-ol monomers and oligomers from dimers to decamers were quantitatively determined by HPLC-FLD in leaves of four Theobroma cacao varieties. Cacao flush leaves had higher procyanidin content than mature leaves. Moniliophthora perniciosa basidiospore infection results in an increase in cacao leaf procyanidins in the inoculated leaves, as well as in the uninoculated, adjacent, older leaves on an actively growing branch, resulting in both a local and systemic increase in procyanidin content in response to infection. Procyanidin oligomers increased significantly in leaves of the less susceptible genotype Scavina 6 upon infection, and total procyanidin levels were higher than in Cacao Comum a more disease susceptible genotype. Selection of genotypes with high constitutive and/or inducible content of procyanidins in young flush leaves may be a strategy to develop witches’ broom disease resistant cultivars.  相似文献   

Effect of single Quercus ilex trees upon spatial and seasonal changes in soil water content in dehesas of central western Spain     

Elena Cubera  Gerardo Moreno 《Annals of Forest Science》2007,64(3):355-364

The spatial and temporal evolution of soil water content (θ) in Quercus ilex dehesas has been investigated to determine how trees modify the soil water dynamics and the nature of tree-grass interactions in terms of soil water use in these ecosystems. Soil physical parameters and θ were measured at different distances from the tree trunk (2–30 m) in the upper 300 cm of soil. θ was measured monthly by TDR during 2002–2005. Tree water potential was determined during the summers of 2004 and 2005. At deeper soil layers, mean θ values were higher beyond than beneath tree canopy during dry periods. θ depletion beyond tree canopy continued even in summer, when herbaceous plants dried up, suggesting that trees uptake water from the whole inter-tree space. Results have shown a high dependence of trees on deep water reserves throughout late spring and summer, which helps to avoid competition for water with herbaceous vegetation.  相似文献   

Growth and development of the arborescent cactus Stenocereus queretaroensis in a subtropical semiarid environment,including effects of gibberellic acid     

Pimienta E  Hernandez G  Domingues A  Nobel PS 《Tree physiology》1998,18(1):59-64

In Stenocereus queretaroensis (Weber) Buxbaum, an arborescent cactus cultivated in Jalisco, Mexico, for its fruits but studied here in wild populations, stem extension occurred in the autumn at the beginning of the dry season, flowering and fruiting occurred in the spring at the end of the dry season, and new roots grew in the summer during the wet season. The asynchrony of vegetative and reproductive growth reduces competitive sink effects, which may be advantageous for wild populations growing in infertile rocky soils. Seasonal patterns of sugars in the roots and especially the stems of S. queretaroensis were closely related to the main phenological stages, becoming lower in concentration during periods of major stem extension. Cessation of stem extension occurred in 100-year-old plants for which injection of GA(3) reinitiated such growth. Isolated chlorenchyma cylinders had maximum extension in a bathing solution containing 0.1 &mgr;M gibberellic acid.  相似文献   

Effect of different levels of dietary sweet orange (Citrus sinensis) peel extract on humoral immune system responses in broiler chickens          下载免费PDF全文

Zohreh Pourhossein  Ali Ahmad Alaw Qotbi  Alireza Seidavi  Vito Laudadio  Gerardo Centoducati  Vincenzo Tufarelli 《Animal Science Journal》2015,86(1):105-110

This experiment was conducted to evaluate the effects of different levels of sweet orange (Citrus sinensis) peel extract (SOPE) on humoral immune system responses in broiler chickens. Three hundred 1‐day broilers (Ross‐308) were randomly allocated to treatments varying in supplemental SOPE added in the drinking water. The experimental groups consisted of three treatments fed for 42 days as follows: a control treatment without feed extract, a treatment containing 1000 ppm of SOPE and a treatment containing 1250 ppm of SOPE. All treatments were isocaloric and isonitrogenous. Broilers were vaccinated with Newcastle disease virus (NDV), avian influenza (AI), infectious bursal disease (IBD) and infectious bronchitis virus (IBV) vaccines. Antibody titer response to sheep red blood cells (SRBC) was higher in the group fed 1250 ppm of SOPE (P < 0.05) as well as for immunoglobulin G (IgG) and IgM. Similarly, antibody titer responses to all vaccines were constantly elevated (P < 0.05) by SOPE enrichment in a dose‐dependent manner. Relative weights of spleen and bursa of Fabricius were unaffected by treatments. Dietary SOPE supplementation may improve the immune response and diseases resistance, indicating that it can constitute a useful additive in broiler feeding. Thus, supplying SOPE in rations may help to improve relative immune response in broiler chickens.  相似文献   

Short-term baths with essential oils of Lippia sidoides,Ocimum gratissimum and Zingiber officinale influence blood parameters and survival of tambaqui (Colossoma macropomum) after infection with Aeromonas hydrophila     

Patrícia Castro Monteiro  Maria Inês Braga de Oliveira  Franmir Rodrigues Brando  Caio Francisco Santana Farias  Cludia Majolo  Francisco Clio Maia Chaves  Humberto Ribeiro Bizzo  Fernanda Loureiro de Almeida O&#x;Sullivan  Maurício Latera Martins  Edsandra Campos Chagas 《Aquaculture Research》2022,53(1):265-275

This study evaluated the effect of short-term baths with the essential oils (EOs) of Lippia sidoides, Ocimum gratissimum and Zingiber officinale on the survival, haematological, biochemical and histopathological parameters of native fish tambaqui (Colossoma macropomum), challenged with Aeromonas hydrophila. After challenge, the fish infected with A. hydrophila received therapeutic baths of 60 min, for five consecutive days. Treatments were as follows: challenged and not treated; challenged and treated with 10 mg L^?1 of gentamicin; challenged and treated with EO of L. sidoides (2.5 and 5.0 mg L^?1); challenged and treated with EO of O. gratissimum (5.0 and 10.0 mg L^?1); challenged and treated with Z. officinale EO (5.0 and 10.0 mg L^?1). The highest survival rates were 89.5% (fish treated with 5.0 mg L^?1 of O. gratissimum EO) and 75.0% (fish treated with 5.0 mg L^?1 of L. sidoides EO). Reductions in the haematocrit percentage, haemoglobin and erythrocyte number were observed in fish treated with L. sidoides and Z. officinale EOs compared with control fish. Mild to moderate damage to the liver tissue of fish after challenge and EO treatments were observed. It is suggested that baths containing O. gratissimum and L. sidoides EOs consist in a viable treatment to increase survival rates of C. macropomum infected with A. hydrophila.  相似文献   

Helminth parasites of freshwater fishes from Cuatro Ciénegas,Coahuila, in the Chihuahuan Desert of Mexico: inventory and biogeographical implications     

Rogelio AGUILAR‐AGUILAR  Andrés MARTÍNEZ‐AQUINO  Héctor ESPINOSA‐PÉREZ  Gerardo PÉREZ‐PONCE DE LEÓN 《Integrative zoology》2014,9(3):328-339

As part of an ongoing inventory of the helminth parasites of freshwater fishes in Mexico, 570 individual fish were collected between Apr 2008 and Oct 2011 in 26 localities along the Cuatro Ciénegas region in Coahuila State, northern Mexico. Seventeen species of hosts, mostly corresponding to Nearctic freshwater elements, were studied. A total of 8324 individual worms were collected during this survey, representing 25 species of helminths, of which 9 were digeneans, 3 monogeneans, 3 acanthocephalans, 9 nematodes and 1 cestode. Most of the records in this checklist represent new host or locality records. The information provided in this checklist may be helpful for our understanding of the biodiversity and historical biogeography of this host–parasite system, because in the Cuatro Ciénegas region occur a Nearctic freshwater fish fauna, along with Neotropical and endemic elements, and from a biogeographical point of view, this may represent a transitional area.  相似文献   

Chronosequence of Technosols at the Peña Colorada mine in Colima,Mexico: a short-term remediation alternative     

Ortega  Jaime Díaz  Sedov  Sergey  Romero  Francisco  Jardines  Luis Gerardo Martínez  Rebolledo  Elizabeth Solleiro 《Journal of Soils and Sediments》2022,22(3):942-956

Journal of Soils and Sediments - The objective of this study was to examine the pedogenetic evolution occurring in technic hard materials from an iron mine through the characterization of a...  相似文献   

Tree–grass interactions for N in Nothofagus antarctica silvopastoral systems: evidence of facilitation from trees to underneath grasses     

Verónica Gargaglione  Pablo L. Peri  Gerardo Rubio 《Agroforestry Systems》2014,88(5):779-790

Nothofagus antarctica forests in south Patagonia are usually used as silvopastoral systems but how grasses and trees compete for specific resources, such as nitrogen in these systems is unknown. To understand interactions between grasses and N. antarctica trees for N, an experiment with ¹⁵N labeled fertilizer was carried out comparing N absorption by grasses growing under trees (silvopastoral system) with an open site. Labeled ¹⁵NH ₄ ¹⁵ NO₃ fertilizer at 10 % atom excess was added in spring at both sites and ¹⁵N was measured in herbage, soil and trees every 30 days during the growing season. Soil was the component that containing the greatest amount of N and greatest ¹⁵N recovery. Grasses growing in the silvopastoral system absorbed almost double of the fertilizer applied than grasses in the open site (32.4 kg N ha^?1derived from fertilizer based on ¹⁵N recovery). Roots were also an important fate for N absorbed, representing 50 and 63 % of total ¹⁵N recovered in grass roots of open and silvopastoral sites, respectively. Trees absorbed 69 % less applied N than grasses in the silvopastoral system; being mainly allocated in small branches, sapwood and fine roots. Overall, ¹⁵N recovery was 65 % higher in the silvopastoral system (tree + grasses) than in the open site (grasses). Silvopastoral system made more efficient use of the ¹⁵N added. These results indicated that N. antarctica trees in the silvopastoral system may “facilitate” fertilizer N absorption of grasses by improving environmental conditions like water availability or by reducing competition for inorganic N between soil microorganisms and plants.  相似文献