Ectomycorrhizal communities within beech (<Emphasis Type="Italic">Fagus sylvatica</Emphasis> L.) forests that naturally regenerate from clear-cutting in northern Spain     

Nieves Goicoechea  Iván Closa  Ana María de Miguel 《New Forests》2009,38(2):157-175

The objectives of the work described here were to evaluate the diversity of ectomycorrhizal (ECM) fungi within Spanish beech (Fagus sylvatica L.) forests subjected to clear-cutting and natural regeneration and to elucidate the extent to which the carbohydrate concentration in roots of trees of different ages and sizes is related to ECM colonization. The study concerned an unmanaged forest, a stand clear-cut in 1996 and another clear-cut in 2001. ECM colonization of beech roots showed seasonal dynamics in the disturbed areas, but the percentage of roots colonized by ECM was not always related to the accumulation of non-structural carbohydrates. The composition of ECM communities differed between different stands and 40% of ECM morphotypes only occurred in disturbed ecosystems. However, comparable numbers of different ECM morphotypes (24, 25) were found in the three beech stands. This finding indicates that ECM diversity was quite high and similar within disturbed and unmanaged areas. This finding suggests that (1) ECM diversity was not affected by the size and age of trees and (2) the potential of ECM inocula remained high within clear-cut areas. Consequently, the introduction of ECM inocula by silvicultural practices would not be needed to improve the regeneration of clear-cut areas described in our study.  相似文献   

Patterns and drivers of the scale of effect of landscape structure on diurnal raptors in a fragmented tropical dry forest     

Martínez-Ruiz  Marisela  Arroyo-Rodríguez  Víctor  Franch-Pardo  Iván  Renton  Katherine 《Landscape Ecology》2020,35(6):1309-1322

Landscape Ecology - Theoretical models propose that the spatial extent at which landscape structure best predicts species responses (scale of effect, SoE) depends on habitat and dietary...  相似文献   

Immunomodulatory effect of swine CCL20 chemokine in DNA vaccination against CSFV     

Tarradas J  Álvarez B  Fraile L  Rosell R  Muñoz M  Galindo-Cardiel I  Domingo M  Dominguez J  Ezquerra A  Sobrino F  Ganges L 《Veterinary immunology and immunopathology》2011,142(3-4):243-251

The objective of this work was to explore whether a plasmid expressing CCL20 chemokine could improve the immune response against CSFV in co-administration with a DNA vaccine expressing the E2 protein. The immunization of pigs with the DNA vaccine formulation, that contains swine CCL20 chemokine, resulted in the homogenous induction of detectable levels of CSFV antibodies at 36 days after the first injection. Remarkably, immunized animals with E2 DNA vaccine in co-administration with the plasmid containing swine CCL20 developed high titers of neutralizing antibodies against homologous and heterologous CSFV strains and were totally protected upon a lethal viral challenge (sterilizing protection). Our results confirm the role of CCL20 to increase antibody-mediated responses. At the same time suggest the ability of CCL20 to enhance the T helper cell response associated with the induction of neutralizing antibodies against CSFV in pigs previously reported. Systemic replication of virulent CSFV in vivo during the acute phase of infection induces type I IFN. Lower average values of IFN alpha were detected in the serum of pigs immunized with pE2 and pCCL20 at 3 days after challenge. The levels of IFN-alpha detected in pigs immunized with pE2 and principally in non-vaccinated challenged animals can be related to viral load in serum at 3 and 7 days post infection and the clinical signs observed. Our results emphasized the capacity of swine CCL20 chemokine to enhance cellular, humoral and anti viral response with an adjuvant effect in the immune response elicited by E2-DNA vaccination against CSFV. To our knowledge, this is the first report demonstrating the adjuvant effect of swine CCL20 to effectively enhance the potential of DNA vaccine in the immune induction and protection against virus challenge in swine infection model.  相似文献   

A synthetic conjugate polysaccharide vaccine against Haemophilus influenzae type b     

Verez-Bencomo V  Fernández-Santana V  Hardy E  Toledo ME  Rodríguez MC  Heynngnezz L  Rodriguez A  Baly A  Herrera L  Izquierdo M  Villar A  Valdés Y  Cosme K  Deler ML  Montane M  Garcia E  Ramos A  Aguilar A  Medina E  Toraño G  Sosa I  Hernandez I  Martínez R  Muzachio A  Carmenates A  Costa L  Cardoso F  Campa C  Diaz M  Roy R 《Science (New York, N.Y.)》2004,305(5683):522-525

Glycoconjugate vaccines provide effective prophylaxis against bacterial infections. To date, however, no commercial vaccine has been available in which the key carbohydrate antigens are produced synthetically. We describe the large-scale synthesis, pharmaceutical development, and clinical evaluation of a conjugate vaccine composed of a synthetic capsular polysaccharide antigen of Haemophilus influenzae type b (Hib). The vaccine was evaluated in clinical trials in Cuba and showed long-term protective antibody titers that compared favorably to licensed products prepared with the Hib polysaccharide extracted from bacteria. This demonstrates that access to synthetic complex carbohydrate-based vaccines is feasible and provides a basis for further development of similar approaches for other human pathogens.  相似文献   

The awakening of invertebrates: The daily dynamics of fishes and mobile invertebrates at Rapa Nui's multiple use marine protected area     

Iván A. Hinojosa  German Zapata-Hernández  Amelia E. Fowles  Carlos F. Gaymer  Rick D. Stuart-Smith 《水产资源保护:海洋与淡水生态系统》2021,31(2):290-303

• 1. On shallow reefs, day-night activity patterns between fishes and invertebrates are presumed to reflect trade-offs between feeding and predation; however, quantitative data on daily community dynamics are scarce. Moreover, night surveys may contribute important information for biodiversity inventories or baselines that normally are not considered.
• 2. This study used standardized day–night visual surveys of fishes and mobile invertebrates on the same transect lines in Rapa Nui (Easter Island) and investigated how diel patterns vary between taxonomic and trophic groups.
• 3. Distinct differences between taxonomic groups were observed, with fishes being more abundant during the day (>twice), whilst invertebrate abundance and richness showed an opposite trend with higher numbers at night (>three times).
• 4. Analysis of trophic groups showed that herbivorous and planktivorous fishes were more abundant during the day. Carnivorous fishes did not show any trends. Top predators (Apex) were observed only at very low abundances. However, a replacement amongst carnivorous fish species between day and night was found, where labridae fishes were practically absent during nights.
• 5. Most of the mobile invertebrates remained concealed during the day, probably due to the influence of predation risk (labrid fishes). The results emphasize the need for consideration of nocturnally active invertebrates in biodiversity inventories or baselines of reefs, which focus heavily only on diurnal surveys.
• 6. Day–night reef surveys should be included in marine protected area planning and monitoring as this provides a better understanding of shallow benthic communities and helps inform proper management decisions.

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Listeriosis of roe-deer in Hungary     

F Kemenes  R Glávits  E Ivánics  G Kovács  A Ványi 《Zentralblatt für Veterin?rmedizin. Reihe B. Journal of veterinary medicine. Series B》1983,30(4):258-265

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Modulation of leptin, insulin, and growth hormone in obese pony mares under chronic nutritional restriction and supplementation with ractopamine hydrochloride     

Buff PR  Johnson PJ  Wiedmeyer CE  Ganjam VK  Messer Iv NT  Keisler DH 《Veterinary therapeutics : research in applied veterinary medicine》2006,7(1):64-72

Horses fed beyond their nutritional requirement and that are physically inactive will develop obesity, which is often accompanied by insulin resistance and heightened risk of laminitis. The use of pharmacologic agents in combination with nutritional restriction may promote weight loss in obese horses unable to exercise because of laminitic pain. This study shows that reducing feed intake of brome grass hay to 75% of ad libitum intake in obese pony mares reduces body weight without induced exercise. Additional supplementation of ractopamine hydrochloride for 6 weeks resulted in a tendency for increased weight loss. Subsequent modulation of obesity-associated hormones, leptin and insulin, as a result of caloric restriction was observed.  相似文献   

Small Demodex populations colonize most parts of the skin of healthy dogs     

Iván Ravera  Laura Altet  Olga Francino  Armand Sánchez  Wendy Roldán  Sergio Villanueva  Mar Bardagí  Lluís Ferrer 《Veterinary dermatology》2013,24(1):168-e37

Background – It is unproven that all dogs harbour Demodex mites in their skin. In fact, several microscopic studies have failed to demonstrate mites in healthy dogs. Hypothesis/Objectives – Demodex canis is a normal inhabitant of the skin of most, if not all, dogs. This hypothesis was tested using a sensitive real‐time PCR to detect Demodex DNA in the skin of dogs. Animals – One hundred dogs living in a humane society shelter, 20 privately owned and healthy dogs and eight dogs receiving immunosuppressive or antineoplastic therapy. Methods – Hair samples (250–300 hairs with their hair bulbs) were taken from five or 20 skin locations. A real‐time PCR that amplifies a 166 bp sequence of the D. canis chitin synthase gene was used. Results – The percentage of positive dogs increased with the number of sampling points. When a large canine population was sampled at five cutaneous locations, 18% of dogs were positive for Demodex DNA. When 20 skin locations were sampled, all dogs tested positive for mite DNA. Our study indicates that Demodex colonization of the skin is present in all dogs, independent of age, sex, breed or coat. Nevertheless, the population of mites in a healthy dog appears to be small. Demodex DNA was amplified from all 20 cutaneous points investigated, without statistically significant differences. Conclusions and clinical importance – Using a real‐time PCR technique, Demodex mites, albeit in very low numbers, were found to be normal inhabitants of haired areas of the skin of healthy dogs.  相似文献   

Quantifying the landscape influence on plant invasions in Mediterranean coastal habitats     

Pablo González-Moreno  Joan Pino  David Carreras  Corina Basnou  Iván Fernández-Rebollar  Montserrat Vilà 《Landscape Ecology》2013,28(5):891-903

Landscape pattern might be an important determinant of non-native plant invasions because it encompasses components influencing the availability of non-native plant propagules and disturbance regimes. We aimed at exploring the relative role of patch and landscape characteristics, compared to those of habitat type and regional human influence on non-native plant species richness. For this purpose, we identified all non-native plant species in 295 patches of four coastal habitat types across three administrative regions in NE Spain differing in the degree of human influence. For each patch, we calculated several variables reflecting habitat patch geometry (size and shape), landscape composition (distribution of land-cover categories) and landscape configuration (arrangement of patches). The last two groups of variables were calculated at five different spatial extents. Landscape composition was by far the most important group of variables associated with non-native species richness. Natural areas close to diverse and urban landscapes had a high number of non-native species while surrounding agricultural areas could buffer this effect. Regional human influence was also strongly associated with non-native species richness while habitat type was the least important factor. Differences in sensitivity of landscape variables across spatial extents proved relevant, with 100 m being the most influential extent for most variables. These results suggest that landscape characteristics should be considered for performing explicit spatial risk analyses of plant invasions. Consequently, the management of invaded habitats should focus not only at the stand scale but also at the highly influential neighbouring landscape. Prior to incorporate landscape characteristics into management decisions, sensitivity analyses should be taken into account to avoid inconsistent variables.  相似文献   

Seasonal dynamics of the physicochemical and biological properties of soils in naturally regenerating,unmanaged and clear-cut beech stands in northern Spain     

Iván Closa  Nieves Goicoechea 《European Journal of Soil Biology》2010,46(3-4):190-199

The physicochemical and biological properties of soils within an unmanaged beech stand and two stands clear-cut in 2001 or 1996 were studied and compared across the year 2008. The clear-cut stands were left to naturally regenerate and exhibited very different levels of tree density. Soil from the stand clear-cut in 2001 had the lowest contents of organic matter and nitrogen, showed high resistance to penetration and the pH varied throughout the seasons. Basal respiration achieved minimum values in summer in both the unmanaged stand and the stand clear-cut in 1996. However, basal respiration slightly fluctuated from spring to autumn in the stand clear-cut in 2001. The seasonal dynamics of protease and phosphatase activities were similar within the three stands: the maximum protease activity was detected in spring and the highest phophatase activity in winter. β-Glucosidase activity in autumn and dehydrogenase in winter were greater in the unmanaged than in the clear-cut stands. Moreover, dehydrogenase activity was extremely low in the stand clear-cut in 1996. Microclimatic parameters within the stands were significantly correlated with several biological properties of soils, with microclimate being strongly determined by the density of trees. Results also suggested that ectomycorrhizal fungi would be key components of the soil microflora in the beech forests.  相似文献