Cloning and mapping of three pig acyl-CoA dehydrogenase genes.

To investigate the structure of porcine genes involved in the beta-oxidation of fatty acid, we isolated the short-chain acyl-CoA dehydrogenase (SCAD), medium-chain acyl-CoA dehydrogenase (MCAD), and long-chain acyl-CoA dehydrogenase (LCAD) genes from the pig. The cDNA of SCAD, MCAD and LCAD genes were 1899 bp, 1835 bp 1835 bp and 1704 bp long and coded for 413-aa, 422-aa and 430-aa precursor proteins, respectively. Three genes, SCAD, MCAD and LCAD were mapped to 14p16.2-23.2, 6q32.4-33, and 15q24.2-26.3, respectively.     

Factors Affecting Latent Infection of Prune Fruit by Monilinia fructicola

ABSTRACT Experiments were conducted in three prune orchards in California. In each orchard, inoculations with Monilinia fructicola, the causal agent of brown rot of stone fruits, were performed on branches of trees at bloom and fruit developmental stages. Five inoculum concentrations were used in each inoculation. Six and four wetness durations were created for each inoculum concentration at bloom and fruit developmental stages, respectively. Fruit were harvested 3 weeks before commercial harvest. The overnight freezing incubation technique was used to promote sporulation and to determine incidence of latent infection (ILI) of fruit brown rot. No differences in ILI among locations were found. A seasonal pattern of bloom and fruit susceptibility to latent infection was determined. Susceptibility to latent infection at bloom stage was at a moderate level and increased to reach the highest level at pit hardening stage. Subsequently, fruit susceptibility to latent infection decreased, reaching the lowest level in early June at embryo growth stage. Thereafter, the susceptibility increased again with fruit development and maturity until harvest. Linear relationships between ILI and inoculum concentration were obtained for most combinations of growth stage and wetness duration. Incidence of latent infection increased linearly with increased wetness duration at bloom stage and increased exponentially with increased wetness duration at early and late fruit developmental stages. The optimum temperatures for latent infection at pit hardening stage ranged from 14 to 18 degrees C, but the effect of temperature on latent infection was reduced at resistant stages. The temperature range favorable to latent infection varied for different wetness durations.     

Cytoplasmic relatedness of apple landraces and cultivars: a molecular analysis

Summary Mitochondrial DNA (mtDNA) diversity has been determined in apple landraces and cultivars, based upon restriction fragment length polymorphisms (RFLPs) for several mitochondrial genes. Our analysis includes three cultivars, Golden Delicious, McIntosh and Delicious, which represent the various patterns of mtDNA polymorphisms previously described (Ishikawa et al., 1992). A total of five RFLPs were detected, allowing classification of the apple genotypes into four cytoplasmic groups: GroupI, Golden Delicious-type; GroupII, McIntosh-type; GroupIII, Delicious-type; and Group IV, Dolgo Crab-type. European landraces and cultivars were assigned to Groups I, II, and III, while chinese crab apples were placed in either Group III or IV.     

Testing the Rothamsted Carbon Model against data from long-term experiments on upland soils in Thailand

We tested the Rothamsted Carbon Model (RothC) against three long‐term (27–28 years) experimental sites on Thai upland soils in order to see how this widely used ‘temperate’ soil carbon turnover model performed in a typical farming region in the tropics. We were able to verify – over a much longer period than had been examined in previous studies – that RothC performs well in a tropical region in plots used for continuous cropping experiments of maize and cassava without organic matter application. However, the model overestimated soil organic carbon (SOC) in some plots to which large amounts of organic matter (rice straw or cassava stalks) were applied. This overestimate could not be attributed to errors in estimating either the amount of C input to the soil or the ratio of decomposable plant materials to resistant plant materials entering the soil. Among many factors affecting SOC dynamics (e.g. weather conditions, soil characteristics, etc.), which are different in tropical regions from temperate regions, we conclude that the activity of soil fauna might be a major factor which makes the performance of RothC worse where much organic matter was applied. We suggest that care should be taken when applying RothC to tropical soils with large amounts of added organic matter.     

How different reforestation approaches affect red soil properties in southern China

Significant differences were found in soil physicochemical and biological effects between various forest restoration approaches of a hilly red‐soil region, southern China. Soil quality was the highest in natural secondary forest (0·95), while in sites revegetated with tea‐oil camellia (Camellia oleifera), Chinese fir (Cunninghamia lanceolata) and slash pine (Pinus elliottii) and control sites, integrated soil quality indices were 0·68, 0·55, 0·36 and 0·04 respectively. The lower soil quality of plantations and controls resulted from increased disruption of soil physical structure, lower quality litter fall, lower litter fall production, reduction in microbial biomass, decline of microbial function and loss of soil nutrients due to periodically artificial tending and accelerated soil erosion. Improvement in soil physicochemical properties and enhanced soil microbial function at a natural secondary forest site demonstrated the inherent restoration of these soils. Hence, natural restoration, as well as reducing human disturbance, is a better approach to improving soil properties than returning farmland to planted woodlands. Copyright © 2005 John Wiley & Sons, Ltd.     

Rice Milling Quality,Grain Dimensions,and Starch Branching as Affected by High Night Temperatures

Important rice grain quality characteristics such as percentage of chalky rice kernels are affected by both high and low night temperatures and by different day and day/night temperature combinations. High nighttime temperatures have also been suspected of reducing rice milling quality including head rice yields. Experiments to confirm or refute this have not been reported. A controlled climate experiment was conducted. Conditions in the chambers were identical except between 2400 and 0500 hours (midnight and 5 am). For those times, two temperature treatments were imposed: 1) 18°C (low temperature treatment) and 2) 24°C (high temperature treatment). Two cultivars were tested: LaGrue and Cypress. The high temperature treatment reduced head rice yields compared with the low temperature treatment. Grain widths were reduced for the high temperature treatment compared with the low temperature treatment. There was no effect of temperature on grain length or thickness. Amylopectin chain lengths 13–24 were increased by the high temperature treatment by ≈1%. Future research will focus on determining whether genetic variability exists among cultivars in their head rice yield response to high temperatures. After identifying a source of resistance to high temperature effects, this characteristic can be incorporated into rice cultivars. In addition, ways to reduce this effect, including biotechnological remedies, have the potential for increasing rice yield and quality.     

Differentiation of the high molecular weight glutenin subunit D t x 2.1 of Aegilops tauschii indicated by partial sequences of its encoding gene and SSR markers

The devastating late blight pathogen Phytophthora infestans infects foliage as well as tubers of potato. To date, resistance breeding has often focused on foliage blight resistance, but tuber blight resistance is becoming more and more important in cultivated potatoes. In this study, a reliable tuber assay for resistance assessment was developed and foliage and tuber blight resistance (R) was compared in four mapping populations. In the RH4X-103 population, tuber blight resistance inherited independently from foliage blight resistance. Three specific R genes against P. infestans were segregating. The Rpi-abpt and R3a genes function as foliage-specific R genes, whereas the R1 gene acts on both foliage and tuber. In the segregating populations SHRH and RH94-076, tuber and foliage blight resistance correlated significantly, which suggests that resistance in foliage and tuber is conferred by the same gene (could be R3b) and quantitative trait loci (QTL), respectively. In the CE population neither tuber nor foliage resistance was observed.     

Determining the vulnerability of Mexican pine forests to bark beetles of the genus Dendroctonus Erichson (Coleoptera: Curculionidae: Scolytinae)

Bark beetles of the genus Dendroctonus are natural inhabitants of forests; under particular conditions some species of this genus can cause large-scale tree mortality. However, only in recent decades has priority been given to the comprehensive study of these insects in México. México possesses high ecological diversity in Dendroctonus–Pinus associations. The geographic coexistence of 12 Dendroctonus species suggests greater vulnerability or threat of tree mortality relative to other areas. We use a biogeographic strategy to identify and rank the areas most vulnerable to tree mortality caused by bark beetles in México. We aim to define the areas that might experience high impact by these insects and also to provide a geographic database useful to forest resource management and conservation policies in México. Using collection records of bark beetles and pines, we develop a quantitative estimate of the threat of beetle infestation of forest areas based on factors including pine and beetle species density, host preference and level of mortality caused by beetle species. A quantitative estimate of forest area vulnerability, the Bark Beetle Threat Index (BBTI) was calculated. Despite the vast area of geographic coincidence of Pinus and Dendroctonus in México, the regions of highest bark beetle pressure are restricted to small zones within some mountain systems. The region that has been most affected by this insect group during the past hundred years is the Transverse Volcanic Belt, followed by the Sierra Madre Occidental and Sierra Madre del Sur. Pine diversity is the major determining factor of BBTI at the regional level, while disturbances from extensive logging and ecosystem change are the key factors behind high BBTIs at the local level.     

Schisandrin B protects against solar irradiation-induced oxidative injury in BJ human fibroblasts

The effects of schisandrin B (Sch B) and its analogs on solar irradiation-induced oxidative injury were examined in BJ human fibroblasts. Sch B and schisandrin C (Sch C) increased cellular reduced glutathione (GSH) level and protected against solar irradiation-induced oxidative injury. The photoprotection was paralleled by decreases in the elastases-type protease activity and matrix-metalloproteinases-1 expression in solar-irradiated fibroblasts. The cytochrome P-450-mediated metabolism of Sch B or Sch C caused ROS production. The results suggest that by virtue of its pro-oxidant action and the subsequent glutathione antioxidant response, Sch B or Sch C may offer the prospect of preventing skin photo-aging.