Assessment of conditions affecting Agrobacterium-mediated soybean transformation using the cotyledonary node explant   总被引：12，自引：0，他引：12  

Margie M. Paz  Huixia Shou  Zibiao Guo  Zhanyuan Zhang  Anjan K. Banerjee  Kan Wang 《Euphytica》2004,136(2):167-179

Conditions affecting Agrobacterium-mediated transformation of soybean [Glycine max (L.) Merr.], including seed vigor of explant source, selection system, and cocultivation conditions, were investigated. A negative correlation between seed sterilization duration and seed vigor, and a positive correlation between seed vigor and regenerability of explants were observed in the study, suggesting that use of high vigor seed and minimum seed sterilization duration can further improve transformation efficiency. Selection schemes using glufosinate or bialaphos as selective agents in vitro were assessed. Glufosinate selection enhanced soybean transformation as compared to bialaphos. The use of 6 mg L^-1 glufosinate during shoot induction and shoot elongation stages yielded higher final transformation efficiency ranging from 2.0% to 6.3% while bialaphos at 4 to 6 mg L^-1 gave 0% to 2.1% efficiency. Including cysteine and DTT during cocultivation increased the transformation efficiency from 0.2–0.9% to 0.6–2.9%. This treatment also improved T-DNA transfer as indicated by enhanced transient GUS expression. Shoot regeneration and Agrobacterium infection were attained in twelve soybean cultivars belonging to maturity groups I-VI. These cultivars maybe amenable to genetic transformation and may provide a valuable tool in soybean improvement programs. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Integration of two simple models in a geographical information system to evaluate salinization risk in irrigated land of the Valencian Community, Spain   总被引：1，自引：0，他引：1  

J.M. de  Paz  F. Visconti  R. Zapata  J. Sánchez 《Soil Use and Management》2004,20(3):333-342

Abstract. Salt affected soil is one of the main problems decreasing the productivity of irrigated agriculture in the Mediterranean area. Simulation models in combination with geographical information systems (GISs) could be used to evaluate the risk of salinization at a regional scale. In this study, two logical models (Pla and Riverside) were combined in a GIS to evaluate the risk of soil salinity and sodicity in the irrigated agriculture of the Valencian Community, Spain. Simple models were chosen so that they could be used at a regional scale. Before running them in a GIS framework, a soil and irrigation water survey was conducted to validate the models with observed data. The Pla model fitted observed data better than Riverside guidelines, probably because parameters of water quality, soil and climate were considered by the Pla model. The resulting maps indicated that the soils most affected by salts are those located in the south of study area, owing to the arid climate, and those areas near the coast due to saline intrusion. Close to 42% of the irrigated area was predicted to be somewhat affected by salinization. The regional-scale soil salinity assessment presented here for the Valencian Community is the first to be made for this region and will be useful in targeting critical areas that may require special management.  相似文献   

Dielectric mixing models for water content determination in woody biomass   总被引：1，自引：0，他引：1  

Ana Paz  Eva Thorin  Clarke Topp 《Wood Science and Technology》2011,45(2):249-259

The aim of this study is to determine the dielectric constant of woody biomass at different water contents and describe its behavior with a dielectric mixing model. The use of the model for determination of water content is also verified. Dielectric constants were calculated from the travel times of electromagnetic waves with a center frequency of 555 MHz through collected biomass samples. The power law, Maxwell–Garnett, and Polder van Santen mixing models were applied to the experimental data. In the models, biomass was considered as a mixture of three phases: a solid solution composed of wood cellular material and bound water, free water, and air. The experimental data was found to be better described by the Maxwell–Garnett model. The use of this model along with an independent validation set for the determination of volumetric water content resulted in a root mean square error of prediction of 0.03 within the investigated volumetric water content range of 0.07–0.29.  相似文献   

A new steroidal saponin with antiinflammatory and antiulcerogenic properties from the bulbs of Allium ampeloprasum var. porrum     

Adão CR  da Silva BP  Parente JP 《Fitoterapia》2011,82(8):1175-1180

A new steroidal saponin was isolated from the bulbs of Allium ampeloprasum var. porrum L. On the basis of chemical evidence, comprehensive spectroscopic analyses and comparison of known compounds, its structure was established as (3β,5α,6β,25R)-6-[(β-d-glucopyranosyl)oxy]-spirostan-3-yl O-β-d-glucopyranosyl-(1→2)-O-[β-D-glucopyranosyl-(1→3)]-β-d-galactopyranoside (1). Results of the present study indicated that the steroidal saponin showed haemolytic effects in the in vitro assays and demonstrated antiinflammatory activity and gastroprotective property using in vivo models.  相似文献   

Melatonin-induced changes in the bovine vaginal microbiota during maternal nutrient restriction     

Riley D Messman  Zully E Contreras-Correa  Henry A Paz  Caleb O Lemley 《Journal of animal science》2021,99(5)

Altering the composition of the bovine vaginal microbiota has proved challenging, with recent studies deeming the microbiota dynamic due to few overall changes being found. Therefore, the objectives of this study were to determine whether gestational age, endogenous progesterone, maternal nutrient restriction, or dietary melatonin altered the composition of the bovine vaginal microbiota. Brangus heifers (n = 29) from timed artificial insemination to day 240 of gestation were used; at day 160 of gestation, heifers were assigned to either an adequate (ADQ; n = 14; 100% NRC requirements) or restricted (RES; n = 15; 60% NRC requirements) nutritional plane and were either supplemented with dietary melatonin (MEL; n = 15) or not supplemented (CON; n = 14). Samples for vaginal microbiota analysis were taken on day 0 (prior to artificial insemination), day 150 (prior to dietary treatments), and day 220 of gestation (60 d post-treatment initiation) using a double guarded culture swab. The vaginal bacterial overall community structure was determined through sequencing the V4 region of the 16S rRNA gene using the Illumina Miseq platform. Alpha diversity was compared via 2-way ANOVA; β diversity was compared via PERMANOVA. The linear discriminant analysis for effect size (LEfSe) pipeline was utilized for analysis of taxonomic rank differences between bacterial communities. Gestational age, progesterone concentration, and maternal nutritional plane did not alter α or β diversity of the vaginal microbiota. However, gestational age resulted in compositional changes at the order, family, and genus level. Moreover, dietary melatonin supplementation did not alter α diversity of the vaginal microbiota but did alter β diversity (P = 0.02). Specifically, melatonin altered the composition at the genus level and increased the prevalence of aerobic bacteria in the vaginal tract. To date, melatonin is the first hormone associated with altering the composition of the bovine vaginal microbiota.  相似文献   

Control of emitter clogging in drip irrigation with reclaimed wastewater   总被引：4，自引：3，他引：4  

I. Ravina  E. Paz  Z. Sofer  A. Marcu  A. Shisha  G. Sagi 《Irrigation Science》1992,13(3):129-139

Summary Experiments were carried out to evaluate the performance of various types of drip irrigation emitters, widely used in Israel, using waste water from a storage reservoir. Fine particulate matter agglomerated by microbial by-products and in-line developed biomass were the principal clogging agents. Clogging fluctuated, increased as water quality deteriorated and decreased when it improved. There were definable differences between emitters of various types as to their clogging susceptibility which were not directly correlated with differences in emitter flow-rate, although, for any particular type, the emitter with smaller discharge was always more sensitive to clogging. The clogging process generally started with emitters located at the far end of the lateral and partial emitter clogging was more common than complete plugging. Overflow was also found in most emitter types and was more common in regulated emitters. Reliable long term operation of most emitter types was achieved with filtration at 80 mesh (180 m opening) combined with daily chlorination and bimonthly lateral flushing. Regular lateral discharge monitoring was found to be a convenient way to detect the initiation of the clogging process. Chlorination was most efficient when applied before the emitters became massively clogged.  相似文献   

Mass mortality of birds of prey caused by Azodrin,an organophosphorus insecticide     

H. Mendelssohn  U. Paz 《Biological conservation》1977,11(3):163-170

Mass increases of the levant vole (Microtus guentheri) are common in alfalfa fields in Israel. Deep ploughing, which is the main factor controlling vole numbers in other agricultural areas, is not possible in alfalfa. As alfalfa is a preferred food, voles in these fields are not attracted to poison baits and cannot be controlled by this means.A particularly striking increase of voles developed during the winter of 1975–1976 on 8 km² of alfalfa fields in the northern Huleh Valley in Israel. This mass increase attracted large numbers of raptors and owls, mainly those wintering and on migration, but also resident species.Because the voles, which reached densities of 2400/ha, caused considerable damage to the alfalfa crop, destroying it completely in some places, the farmers sprayed the fields with Azodrin (Monocrotophos). This persistent insecticide is recommended in Israel only for the control of pests on cotton and in orchards. The dangers to wildlife described on the original label do not appear in the Hebrew translation.Due to secondary poisoning with Azodrin there was a mass mortality of raptors and owls that had fed on poisoned voles and birds on these 8 km². 116 raptors and 29 owls were found dead during December 1975 through February 1976; 53 raptors and 16 owls were found poisoned but still alive, and were saved and later released. According to repeated counts of the black kite (Milvus migrans) population in the area it was estimated that about twice as many birds as those found were affected. Since it is probable that no poisoned birds could recover in the field, about 400 birds of prey had been destroyed on 8 km² within three months.  相似文献   

An unusual congenital cardiac anomaly in a Dexter calf     

GP REPPAS  R. RHEINBERGER  PJ CANFIELD  GF WATSON 《Australian veterinary journal》1996,73(3):115-116

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Factors influencing urban tree planting program growth and survival in Florida,United States     

Andrew K. Koeser  Edward F. Gilman  Maria Paz  Chris Harchick 《Urban Forestry & Urban Greening》2014,13(4):655-661

High levels of mortality after installation can limit the long-term benefits associated with urban tree planting initiatives. Past planting projects funded by the Florida Forest Service were revisited two to five years after installation to document tree survival and growth and assess program success. Additionally, various site (e.g., soil compaction, installed irrigation) and tree-related (e.g., species, nursery production method, initial size at planting) factors were noted to assess their impact on tree growth. Results show that the overall establishment rate for the 26 sites (n = 2354 trees) was high, with 93.6% of trees alive at the time of final inspection. On-site irrigation played a significant role in tree survival and growth, especially for Magnolia grandiflora (97.7% survival on irrigated sites; 73.8% survival on non-irrigated sites). Findings from this work validate the effectiveness of current program policies which include maintenance of tree quality within the first year after planting, and offer further insights regarding the impacts of season of planting and initial size of nursery stock on plant growth and development.  相似文献   

Evaluation of Three Different Extenders for Use in Emergency Salvaging of Epididymal Spermatozoa from a Cantabric Brown Bear     

L Anel  M Alvarez  E Anel  F Martinez‐Pastor  F Martinez  C Chamorro  P de Paz 《Reproduction in domestic animals》2011,46(1):e85-e90

The Cantabrian brown bear (Ursus arctos) constitutes an endangered subpopulation of the European brown bear in the north of Spain. We have carried out a post‐mortem recovery of epididymal spermatozoa from a Cantabrian brown bear (7 years old, 170 kg; 30 min post‐mortem), cryopreserving those recovered from the cauda epididymis (929 × 10⁶ spermatozoa, 54% motile, 82% cytoplasmic droplets). For freezing, three extenders based on Test‐Tris‐Fructose + 4% glycerol were used: (1) 325 mOsm/kg and 10% egg yolk; (2) 430 mOsm/kg and 15% egg yolk; (3) 300 mOsm/kg, Equex‐EDTA and 20% egg yolk. After thawing, we obtained higher motility for extender 3 (31%), but extender 2 yielded the highest viability (66.9%) and mitochondrial activity (67.1%). Caffeine stimulation showed that extender two rendered the highest recovery values of post‐thawing motility with respect to the fresh sample. In conclusion, epididymal spermatozoa of brown bear can be frozen applying an extender with osmolality similar to epididymal environment.  相似文献