Pasting properties of transgenic lines of a commercial bread wheat expressing combinations of HMW glutenin subunit genes

Seven transgenic lines of a commercial wheat (Triticum aestivum L.) cultivar expressing transgenic subunits 1Ax1, 1Dx5 and 1Dy10, alone or in combination have been developed. Pasting properties were determined in these transgenic lines using a Rapid Visco Analyser (RVA) in order to determine the possible impact of HMW-GS transgene expression on the starch properties. Expression of the HMW-GS transgenes increased the proportions of the corresponding 1Ax, 1Dx and 1Dy subunits affecting significantly the ratios of HMW-GS:LMW-GS and x-type:y-type HMW-GS. Starch granule size distribution varied significantly among all transgenic lines, with the Anza control and transgenic line T616 (expressing subunits 1Ax1 and 1Dy10) showing the highest and the lowest percentage of B granules, respectively. All transgenic lines increased the water-binding capacities (WBC) at 25 °C and 90 °C. Line T606 (expressing subunits 1Ax1 and 1Dx5) and line T590 (expressing subunit 1Dy10) showed the lowest and the highest values for peak viscosity, respectively. Notably, lines expressing only transgenic x-type subunits (T580, T581 and T606), with high ratios of x-type:y-type HMW-GS, had low peak viscosities, final viscosities and breakdown viscosities. Line T590 had the highest breakdown viscosity while lines T606 and T581 had the lowest.     

Factors controlling Eucalyptus productivity: How water availability and stand structure alter production and carbon allocation

Wood production varies substantially with resource availability, and the variation in wood production can result from several mechanisms: increased photosynthesis, and changes in partitioning of photosynthesis to wood production, belowground flux, foliage production or respiration. An understanding of the mechanistic basis for patterns in wood production within a stand and across landscapes requires a complete annual carbon budget. We measured annual carbon flows to wood production, foliage production and total belowground carbon flux (the sum of root production, root respiration, and mycorrhizal production and respiration) from ages three to five years in clonal Eucalyptus plantations at four sites in Brazil to test if fertility, water availability and stand structure changed wood production and by what mechanism. We also quantified the patterns in light interception and the efficiency of light use to provide additional mechanistic insights into growth responses and to determine if light-use efficiency was related to changes in flux and partitioning.     

Influence of the soil water holding capacity on the potential distribution of forest species. A case study: the potential distribution of cork oak (<Emphasis Type="Italic">Quercus suber</Emphasis> L.) in central-western Spain

This study reports a parametric approach to the climatic and edaphoclimatic potential distribution of the cork oak (Quercus suber L.) in central-western Spain together with an analysis of the influence of the maximum soil water holding capacity (WHC) on such potential distribution. To these ends, we employed 12 climatic and 2 edaphoclimatic parameters of eco-physiological influence derived from the current distribution of cork oaks. The climatic and edaphoclimatic parameters elaborated for two extreme WHC values (50 and 250 mm) are calculated for the whole study area and are mapped by means of a digital elevation model and a geographic information system. The results point to an important climatic potential area for high soil WHC values but there is also a remarkable dependence on this latter parameter, mainly in the Duero basin, since the limits of the climatic potential area are reduced strongly as WHC decreases. We deduce certain other conclusions as regards the importance of this variable in the potential distribution of species and in forestation and reforestation projects using this species.     

Full‐Thickness Skin Grafting to Cover Equine Wounds Caused by Laceration or Tumor Resection

Objective: To describe and evaluate full‐thickness skin grafting of equine wounds. Study Design: Case series. Animals: Adult horses (n=6). Methods: A full‐thickness graft was harvested from the pectoral region with the horse anesthetized or standing and sedated after local anesthetic infiltration. Grafts were attached to the cutaneous margin of the wound with staples and/or sutures if the horse was anesthetized or if the recipient site was desensitized. Cyanoacrylate glue was used to attach the grafts to the cutaneous margin of the wound of 3 horses. Medical records were reviewed for history, physical examination findings, grafting technique, postoperative complications, and outcome. Results: Three horses had full‐thickness skin grafting to cover a fresh defect created by excision of a cutaneous neoplasm, and 3 horses had full‐thickness skin grafting to cover a fresh or granulating laceration. Grafts were completely accepted in 5 horses. The superficial layers of all grafts sloughed, but the final cosmetic appearance of accepted grafts was good. Conclusions: Full‐thickness skin grafting can be performed in standing sedated horses with good cosmesis, especially when the meshed graft is expanded minimally. Clinical Relevance: Good acceptance of a full‐thickness graft can be expected, regardless of whether the graft is applied to a fresh or granulating wound.     

Composite materials of thermoplastic starch and fibers from the ethanol-water fractionation of bagasse

The aim of this study was to evaluate the potential of the fibrous material obtained from ethanol-water fractionation of bagasse as reinforcement of thermoplastic starches in order to improve their mechanical properties. The composites were elaborated using matrices of corn and cassava starches plasticized with 30 wt% glycerin. The mixtures (0, 5, 10 and 15 wt% bagasse fiber) were elaborated in a rheometer at 150 °C. The mixtures obtained were pressed on a hot plate press at 155 °C. The test specimens were obtained according to ASTM D638. Tensile tests, moisture absorption tests for 24 days (20-23 °C and 53% RH, ASTM E104), and dynamic-mechanical analyses (DMA) in tensile mode were carried out. Images by scanning electron microscopy (SEM) and X-ray diffraction were obtained. Fibers (10 wt% bagasse fiber) increased tensile strength by 44% and 47% compared to corn and cassava starches, respectively. The reinforcement (15 wt% bagasse fiber) increased more than fourfold the elastic modulus on starch matrices. The storage modulus at 30 °C (E_30 °C′) increased as the bagasse fiber content increased, following the trend of tensile elastic modulus. The results indicate that these fibers have potential applications in the development of biodegradable composite materials.     

Size-dependent pattern of wildfire ignitions in Portugal: when do ignitions turn into big fires?

Not all wildfire ignitions result in burned areas of a similar size. The aim of this study was to explore whether there was a size-dependent pattern (in terms of resulting burned area) of fire ignitions in Portugal. For that purpose we characterised 71,618 fire ignitions occurring in the country in the period 2001–2003, in terms of population density in the local parish, land cover type and distance to roads. We then assigned each ignition into subsets of five classes according to the resulting burned area: >5 ha, >50 ha, >100 ha, >250 ha, >500 ha. The probability of an ignition resulting in different burned area classes was modelled using binary logistic regression, and the relative importance, strength and signal (positive or negative) of the three explanatory variables compared across the models obtained for the different classes. Finally, we explored the implications of land cover and population density changes during the period 1990–2000 in Portugal for the likelihood of ignitions resulting in wildfires >500 ha. Population density was the more important variable explaining the resulting burned area, with the probability of an ignition resulting in a large burned area being inversely related to population density. In terms of land cover, ignitions resulting in large burned areas were more likely to occur in shrubland and forest areas. Finally, ignitions farther away from roads were more likely to result in large burns. The current land cover trends (decrease of agricultural land and increase in shrublands) and population trends (decline in population densities except near the coast) are increasing the probability that ignitions will result in large fires in vast regions of the country.     

Sperm motility and fertilization performance of Nodipecten nodosus (L., 1758) exposed at two different cryoprotectants

Cryopreservation is a valuable tool for aquaculture as it provides continuous seed production, regardless of the spawning season of the brood stock. The selection of a suitable cryoprotectant with low toxicity and high water solubility is important to avoid membrane injuries and intracellular ice crystallization. This study has been aimed at the assessment of the toxic effects of two usually applied cryoprotectants, 1‐2 propylene glycol (PG) and methanol (MetOH), on spermatozoa of the of lion‐paw scallop Nodipecten nodosus, by evaluating the sperm motility and the development of D larvae after fertilization procedure. Sperm was exposed at room temperature (22°C) for 10, 20 and 30 min to different concentration ranges of two cryoprotectants. Regarding the sperm motility, PG5%, PG7%, MetOH4% and MetOH6% did not show differences compared to control (semen incubated in seawater) (P < 0.05). The development of D larvae was not affected by the exposition to PG5%, MetOH 4% and MetOH 6%. These results indicate the potential use of both cryoprotectants for cryopreservation procedures.     

Race structure and frequency of avirulence genes in the western Canadian Leptosphaeria maculans pathogen population,the causal agent of blackleg in brassica species

Leptosphaeria maculans is the causal agent of blackleg, a serious disease on canola/rapeseed in western Canada, Australia and Europe. Genetic resistance and extended crop rotation provided effective disease control in western Canada for years but the emergence of new pathogen races has reduced the effectiveness of current management strategies. The objective of this study was to analyse L. maculans isolates derived from canola stubble in commercial fields collected in 2010 and 2011 across western Canada for the presence and frequency of avirulence (Avr) genes. A total of 674 isolates were examined for the presence of Avr alleles AvrLm1, AvrLm2, AvrLm3, AvrLm4, AvrLm6, AvrLm7, AvrLm9, AvrLepR1, AvrLepR2 and AvrLmS using a set of differential host genotypes carrying known resistance genes or PCR amplification of AvrLm1, AvrLm6 and AvrLm4–Lm7. Certain alleles were more prevalent in the pathogen population, with AvrLm6 and AvrLm7 present in >85% of isolates, while AvrLm3, AvrLm9 and AvrLepR2 were present in <10% of isolates. A total of 55 races (different combinations of Avr alleles) were detected, with the two most common ones being AvrLm2–Lm4–Lm6–Lm7 and AvrLm2–Lm4–Lm6–Lm7–LmS. Races carrying as many as seven and as few as one known Avr allele were detected. Selection pressure from the race‐specific resistance genes carried in canola cultivars has probably played a significant role in the current Avr profile, which may have also contributed to the recent increase in blackleg observed in western Canada.     

Artemia sp. Proportions and Effects on Survival and Growth of Pintado,Pseudoplatystoma corruscans Larvae

ABSTRACT

The aim of the present study was to evaluate the survival and growth of larvae (L) of pintado, Pseudoplatystoma corruscans, fed different Artemia sp. proportions: 50, 200, 350, 500, 650, 800, and 950 Artemia nauplii per larva per day, in a complete randomized design. Water salinity was 1.7%, and larviculture lasted for a period of 15 days, which was divided into three individual 5-day trials. Larvae were stocked at a density of 15 per liter and kept in the dark. The concentrations of un-ionized ammonia-N and nitrite-N were directly proportional to the increase in prey density (P < 0.05). Regression analysis showed increased survival and growth rates up to 200, 350, and 500 nauplii/L/day, for the first, second, and third trials, respectively. These results indicate that larval food intake is related to ontogenetic development stage.