Broad resistance to acetohydroxyacid‐synthase‐inhibiting herbicides in feral radish (Raphanus sativus L.) populations from Argentina          下载免费PDF全文

Claudio E Pandolfo  Alejandro Presotto  Florencia Moreno  Ida Dossou  Juan P Migasso  Ernesto Sakima  Miguel Cantamutto 《Pest management science》2016,72(2):354-361

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Response of ants to grazing disturbance at the central Monte Desert of Argentina: community descriptors and functional group scheme     

Silvia CLAVER  Susana L SILNIK  Florencia F CAMPóN 《干旱区科学》2014,6(1):117-127

Livestock ranching is one of the main productive activities in arid regions of the world.Grazing produces changes in animal as well as plant communities(e.g.richness,abundance and species dominance relationships).Ants are good biological indicators due to the environmental fidelity of some of their community parameters.We described the functional structure of the ant community in the central Monte of Mendoza,Argentina,and examined the effect of grazing using richness,diversity and the functional group scheme.We used pitfall traps to sample ants at a reserve with 30-year cattle exclusion and at an adjacent ranch.Eleven of the 27 recorded species showed significant differences in their abundance and two species were absent at the ranch.While richness and diversity did not reflect these differences,functional groups did.Hot Climate Specialists were more abundant at the ranch while Cryptic Species and Generalized Myrmicinae increased at the reserve.This study supports the utility of the functional group scheme to study the effects of grazing disturbance in ant communities of arid regions.  相似文献   

Woody understory plant diversity in pure and mixed native tree plantations at La Selva Biological Station,Costa Rica     

Rose Butler  Florencia Montagnini  Pablo Arroyo 《Forest Ecology and Management》2008

Tree plantations can be an important tool for restoration of abandoned pasturelands in the tropics. Plantations can help speed up secondary forest succession by improving soil conditions, attracting seed-dispersal agents, and providing shade necessary for understory growth. In this study, abundance and richness of understory regeneration was measured in three native tree plantations 15–16 years of age at La Selva Biological Station in the Costa Rican Caribbean lowlands. Each plantation contained tree species in pure plots, a mixture of the species, and natural regeneration plots (no trees planted). The greatest abundance of regeneration was found in the understory of pure plots of Jacaranda copaia (Aubl.) D.Don., Vochysia guatemalensis Donn.Sm., Dipteryx panamensis Benth, Vochysia ferruginea Mart., and in two mixed stands, while the lowest was found in the natural regeneration treatments with about half the values as in the plantation stands. There was a significant negative correlation between percent canopy openness and abundance of regeneration in the understory. Two distinctive clusters separated the regeneration treatments from the mixed and pure plantations at a very low Bray–Curtis similarity value. The natural regeneration treatments are separated from mixed and pure plantations in the two-dimensional ordination. The lack of difference between the understory make-up of pure and mixed plantations in abundance, species richness, and seed-dispersal syndromes of understory species suggests that planting mixed stands is not necessarily superior to planting pure stands for promoting understory diversity of woody species. While regeneration of woody species can be faster under pure- or mixed-species plantations than in open pastures, the abundance, richness and species composition depends on each plantation species, or species assemblages in case of the mixtures.  相似文献   

Allometric relationships and reforestation guidelines for <Emphasis Type="Italic">Maclura tinctoria,</Emphasis> an important multi-purpose timber tree of Latin America     

Irene Montes-Londoño  Florencia Montagnini  Mark S. Ashton 《New Forests》2018,49(2):249-263

As reforestation and restoration processes gain momentum across the world native tree species are being established for production, conservation and restoration purposes in agricultural landscapes. One such tree with promise is dinde [Maclura tinctoria (L.) D. Don ex Steud]; a multi-purpose, Neotropical tree species that is being widely introduced on to farms of the coffee axis region in the Latin American Andes. No formal studies have been made that examine its potential for reforestation. In this study we aim to measure and define the relationships between age, bole size (dbh), tree height, and crown size of planted dinde trees for the development of spacing guidelines at time of planting and for thinning. We also sought to identify whether tree growth is influenced by various measures of soil fertility. We studied these relationships on dinde trees planted at twelve farms in the central Andean foothills of Colombia. Our results are the first to show dinde has comparable growth to other native and exotic trees used for reforestation in Latin America. Strong relationships exist for tree age and diameter at breast height (DBH) with crown size and height. Based on these relationships we developed spacing and thinning guidelines for timber production in plantation and silvo-pastoral circumstances. Soils were generally fertile but varied between farms. Growth varied with soil primarily related to pH and calcium, and secondly to soil nitrogen and organic matter. Our results provide preliminary information for the forester and/or the farmer on expected growth and size relationships for given ages in relation to soil fertility for planted trees. As more trees are planted on a wider array of soils and providing a greater diversity of ages further studies are necessary for refining guidelines.  相似文献   

Assessing the efficacy of Duddingtonia flagrans chlamydospores per gram of faeces to control Haemonchus contortus larvae     

Nadia Florencia Ojeda-Robertos  Juan Felipe de Jesus Torres-Acosta  Armando Jacinto Aguilar-Caballero  Armín Ayala-Burgos  Ligia Amira Cob-Galera  Carlos Alfredo Sandoval-Castro  Roberto Carlos Barrientos-Medina  Pedro Mendoza de Gives 《Veterinary parasitology》2008

The aims were (a) to quantify the number of Duddingtonia flagrans chlamydospores per gram of faeces (CPG) recovered from sheep administered with different oral doses and, (b) to describe the relationship between CPG and eggs per gram of faeces (EPG) on the efficacy to reduce Haemonchus contortus infective larvae. Three doses of chlamydospores per kg BW were orally administered during seven days: (T1) non treated control group, (T2) 1 × 10⁶, (T3) 2.5 × 10⁶ and (T4) 5 × 10⁶. Three lambs, infected with H. contortus, were used per group. Faeces were obtained from the rectum of each lamb during the fungal administration period (days 0–6) and for six days after that period. Four coproculture replicates were made from each animal in days 2, 4, 6, 8 and 10. A higher chlamydospore dose produced higher CPG in faeces (p < 0.05), but a clear dose dependent effect was not found either in the larvae reduction or in the CPG:EPG ratio. When ratios were re-analyzed, independently of the treatment groups of origin, a better efficacy was obtained with a ratio from 5 to 10 CPG:EPG and a higher ratio (>10 per egg) showed a lower reduction efficacy (p < 0.05). The binomial analysis showed that for each unit of increment in CPG:EPG ratio there was a reduction of larvae number until a point (between 5 and 10 CPG:EPG) where no further reduction was detected. The surface response test indicated that the number of larvae was reduced by CPG until possible saturation. The highest CPG:EPG ratios did not necessarily improve efficacy of D. flagrans.  相似文献   

Equine Chorionic Gonadotropin (eCG) improves bucks’ semen quality during the nonbreeding season          下载免费PDF全文

Florencia Beracochea  María Noel Viera  Lucía Acevedo  Julián Santiago‐Moreno  Rodolfo Ungerfeld 《Reproduction in domestic animals》2018,53(5):1096-1102

In most goat breeds, testosterone serum concentration and semen quality decrease during the nonbreeding season. However, bucks reproductive activity may be stimulated with the administration of equine chorionic gonadotropin (eCG). Therefore, the aim of this study was to determine whether the repeated administration of eCG stimulates the reproductive status of bucks during the nonbreeding season. The study was performed with 19 bucks that were assigned to a group that was treated with eCG (GeCG) and an untreated control group (GCon). The GeCG bucks received an initial dose of 800 IU of eCG (Day 0), followed by four doses of 500 IU administered every 5 days beginning on Day 5. Serum testosterone and anti‐eCG antibody concentrations, testicular and seminal traits were determined until Day 60. Testosterone concentration (from Day 3 to 21: p < 0.0001), anti‐eCG titre (from Day 12 to 44: p ≤ 0.01), percentage of motile spermatozoa (Day 6: p = 0.006 and 14: p = 0.001) and of spermatozoa with progressive motility (Day 6: p = 0.01 and 14: p = 0.002) and the percentage of spermatozoa with functional membrane (Day 6: p = 0.02 and 22: p = 0.008) were higher in GeCG than in GCon bucks. Also in frozen‐thawed samples, the percentage of motile spermatozoa tended to be higher in GeCG than that of GCon bucks (p = 0.07). In conclusion, the administration of eCG during the nonbreeding season stimulated the secretion of testosterone and improved fresh and possibly frozen‐thawed semen quality. However, it also resulted in an increase in anti‐eCG antibody titre.  相似文献   

High Genetic Diversity of Anaplasma marginale Detected from Philippine Cattle     

Adrian Patalinghug YBA?EZ  Rochelle Haidee D. YBA?EZ  Florencia G. CLAVERIA  Mary Jane CRUZ-FLORES  Xuen XUENAN  Naoaki YOKOYAMA  Hisashi INOKUMA 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2014,76(7):1009-1014

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Protease inhibitor activity is associated to a basic chitinase from potato but not to an acidic one   总被引：1，自引：0，他引：1  

Milagros Machinandiarena  Marta Castillo  Florencia Olivieri  Gustavo Daleo  Claudia Oliva 《Potato Research》2001,44(2):187-195

Summary Several pathogenesis-related proteins, which are produced in plants submitted to stress, have been identified as chitinases. We have previously described that a potato basic chitinase strongly inhibited the activity of an aspartic protease isolated from the same source. In this work, we have tested the activity of two potato chitinases as protease inhibitors. A basic chitinase (ChiB) inhibited trypsin, chymotrypsin, subtilisin, proteinase K and a serine protease ofFusarium sp. An acidic one (ChiA) did not show inhibitory activity. The kinetics of trypsin inhibition by ChiB revealed different patterns of inhibition with azocasein and BAPNA. Metal ions affected differentially both activities, suggesting that ChiB is a bifunctional protein. These results and those reported by other authors suggest a new physiological role for pathogenesis-related proteins. However, results presented in this paper suggest that the protease inhibitor activity is not a general characteristic of potato chitinases.  相似文献   

The major genetic determinants of HIV-1 control affect HLA class I peptide presentation     

International HIV Controllers Study  Pereyra F  Jia X  McLaren PJ  Telenti A  de Bakker PI  Walker BD  Ripke S  Brumme CJ  Pulit SL  Carrington M  Kadie CM  Carlson JM  Heckerman D  Graham RR  Plenge RM  Deeks SG  Gianniny L  Crawford G  Sullivan J  Gonzalez E  Davies L  Camargo A  Moore JM  Beattie N  Gupta S  Crenshaw A  Burtt NP  Guiducci C  Gupta N  Gao X  Qi Y  Yuki Y  Piechocka-Trocha A  Cutrell E  Rosenberg R  Moss KL  Lemay P  O'Leary J  Schaefer T  Verma P  Toth I  Block B  Baker B  Rothchild A  Lian J  Proudfoot J  Alvino DM 《Science (New York, N.Y.)》2010,330(6010):1551-1557

Infectious and inflammatory diseases have repeatedly shown strong genetic associations within the major histocompatibility complex (MHC); however, the basis for these associations remains elusive. To define host genetic effects on the outcome of a chronic viral infection, we performed genome-wide association analysis in a multiethnic cohort of HIV-1 controllers and progressors, and we analyzed the effects of individual amino acids within the classical human leukocyte antigen (HLA) proteins. We identified >300 genome-wide significant single-nucleotide polymorphisms (SNPs) within the MHC and none elsewhere. Specific amino acids in the HLA-B peptide binding groove, as well as an independent HLA-C effect, explain the SNP associations and reconcile both protective and risk HLA alleles. These results implicate the nature of the HLA-viral peptide interaction as the major factor modulating durable control of HIV infection.  相似文献   

Using agroforestry to improve soil fertility: effects of intercropping on <Emphasis Type="Italic">Ilex paraguariensis</Emphasis> (yerba mate) plantations with <Emphasis Type="Italic">Araucaria angustifolia</Emphasis>     

Tal Ilany  Mark S. Ashton  Florencia Montagnini  Constanza Martinez 《Agroforestry Systems》2010,80(3):399-409

This study assessed the use of agroforestry to improve soil nutrient properties in plantations containing Ilex paraguariensis St. Hilaire (yerba mate). Intercropping within tree plantation systems is widely practiced by farmers around the World, but the influence of different species combinations on system performance still requires further investigation. I. paraguariensis is a major South American crop commonly cultivated in intensive monocultures on low activity clay soils, which are highly prone to nutrient deficiencies. Study plots were established in 20 plantations in Misiones, Argentina. These involved two species combinations (I. paraguariensis monoculture and I. paraguariensis intercropped with the native tree species Araucaria angustifolia) and two age classes (30 and 50 years old). Chemical soil samples were analysed to determine Ca, Mg, K, P, N, C and Al concentrations, effective CEC (eCEC) and pH at two soil depths (0–5 cm and 5–10 cm). In the younger plantations, the agroforestry sites had lower nutrient levels than I. paraguariensis monoculture sites. However, the monoculture plantations were more susceptible than agroforestry sites to a decline in soil nutrient status over time, particularly with respect to Ca, eCEC, N and C for both soil depths. P concentrations were below detection limits for all sites, potentially reflecting the high P-fixing capacity of the kaolinic soils of this region. While agroforestry systems may be better at maintaining soil quality over time, significant growth increase of I. paraguariensis was apparent only for the monoculture sites.  相似文献