Barrier analysis detected genetic discontinuity among Ethiopian barley (Hordeum vulgare L.) landraces due to landscape and human mobility on gene flow

The rate of gene flow is greatly affected by the ability of a species to move from one location to another. In Ethiopia the presence of diverse agro-ecological zones, climatic features, rugged mountains and isolated valleys affected the seed-mediated gene flow among regions. Hence, this study was aimed at investigating and detecting presence of any gene barriers and genetic differentiation among regions. Thus, the study was proposed to test whether the high genetic diversity of barley in Ethiopia was due to a reduced gene flow resulting from geographic barriers and/or effects of human activities. A total of 199 barley landraces collected from 10 different geographic regions and altitudes of Ethiopia were analyzed for 15 molecular markers. A barrier analysis was conducted to identify any geographic areas with pronounced genetic discontinuity between the regions that can be interpreted as barriers to gene flow. The result obtained from analysis of molecular variances indicated high genetic variation within regions rather than between regions. Despite high gene flow among regions, we were able to detect genetic discontinuity due to landscape and human mobility for certain barley growing areas. Hence, it was postulated that these barriers have to be considered in genetic resource sampling strategies.     

Genetic diversity and population structure analysis of isolates of the rice false smut pathogen Ustilaginoidea virens in India

Genetic diversity assessment and population structure analysis are essential for characterization of pathogens and their isolates. Markers are essential tools for exploring genetic variation among the isolates. False smut of rice caused by Ustilaginoidea virens, formerly Villosiclava virens, is a major emerging disease of rice in India. A high level of variability is observed at the field level, but no information is available from India on genetic diversity and population structure. This is the first report of genetic diversity and population structure of U. virens from India that included 63 isolates distributed across the vast geographical area of eastern and north-eastern India (18.9 to 26.7°N and 82.6 to 94.2°E). Seventeen RAPDs and 14 SSRs were identified as polymorphic and a total of 140 alleles were detected across the populations. The average number of alleles per locus for each primer was 4.5. All the isolates were grouped into two major clusters, with partial geographical segregation that was supported by principal coordinate analysis. Mantel test suggested genetic distance within the isolates increased with increasing geographical distance. Analysis of molecular variation showed more genetic variation within populations and less among populations. This outcome will help in understanding genetic diversity of U. virens from eastern and north-eastern India and in planning effective management strategies.     

An unusual source of lead causing poisoning

Extract

Sir,—I recently added two nine-month-old heifers showing typical symptoms of lead poisoning, but when the usual search for the source was found. On my third visit the owner produced a half-chewed tape measure which he remembered having mislaid the day before the oneset of the illness of the heifers. Although not expecting it to be the source of the lead, I examined it and found a residue of silvery threads after the organic matter had been calcined. These threads, when dissolved in nitric acid and tested with a solution of potassium iodide, gave a heavy precipitate of “golden spangles” of lead iodide. The heifers had chewed about two feet of tape, which apparently contained enough lead cause the very severe symptoms. After three weeks, they are now recovering.     

Acellular Dermal Matrix for Surgical Repair of Ventral Hernia in Horses

The aim of the present study was to evaluate acellular dermal matrix (ADM) of rat origin for the repair of ventral hernia in horses. The skin from rats, to be used as a graft, was de-epithelialized using hypertonic solution and further decellularized with 0.5% sodium dodecyl sulfate and 0.25% tri-(n-butyl)-phosphate. Under general anesthesia, the hernial ring was exposed and repaired with the ADM graft using inlay graft technique. Blood samples were collected at postimplantation days 0, 15, and 30 and were used for sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis to assess the serum protein concentration of the animals, as well as for gelatin zymography for the identification of matrix metalloproteinases. All animals had an uneventful recovery without clinical signs of wound dehiscence, infection, or recurrence of hernias during 6-month follow-up period. Sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis of concentration of the serum proteins revealed that this was increased at day 15 and had decreased again at day 30. Gelatin zymography showed only one major band of 92 kDa in the serum of all the horses with the implant, but the relative amount of 92 kDa was higher at day 15 as compared with day 0 and day 30. It may be concluded that ADM of rat origin can be used safely in horses for repair of ventral hernia.     

Comparative studies on endocrine status and gene expression of hepatic carbohydrate metabolic enzymes in juvenile GIFT tilapia (Oreochromis niloticus) fed high‐carbohydrate diets

The effects of high‐carbohydrate diets on endocrine status and gene expression of hepatic metabolism enzymes in genetically improved farmed tilapia (GIFT) juveniles (Oreochromis niloticus) at different sampling times were investigated. Two isonitrogenous (28% crude protein) and isolipidic (5% crude lipid) diets were formulated to contain 40% gelatinized wheat starch (WS) or glucose (GLU). Diets were assigned to triplicate groups of 30 fish (initial weight: 51 g) for 42 days. At the end of the trial, there were no significant difference in growth between WS group and GLU group. Hepatosomatic and visceral index and liver glycogen in juveniles were not significantly influenced by high‐carbohydrate diets on Day 42 (P > 0.05). Plasma glucose was higher in the GLU group than the WS group from Day 7 onwards. Data on gene expression showed that G6PD, but not GK and G6Pase, were affected by high‐carbohydrate diet. The levels of G6PD in the GLU group on Days 35 and 42 were significantly higher than those in the WS group. Serum IGF‐I levels of both groups significantly decreased on Day 42, whereas serum insulin levels were unaltered by high‐carbohydrate diet. The serum GH level decreased significantly in the GLU group compared with the WS group. Overall, our data suggest that high‐glucose diets were efficiently used as an energy source by GIFT tilapia juveniles, and significantly affected liver lipogenic activity and serum GH levels.     

Bilateral renal agenesis in an alpaca cria

A 3-day-old male alpaca cria was presented for lack of vigor and failure to urinate since birth. Based on the history, laboratory data, ultrasonographs, surgical findings, and postmortem examination, the cria was diagnosed with bilateral renal agenesis and hypoplastic bladder, a congenital condition rarely seen in veterinary medicine.     

Nanofibers from bagasse and rice straw: process optimization and properties

Nanofibers (NF) were isolated from bleached bagasse and rice straw pulps. The pulps were refined using high-shear ultrafine grinder and then homogenized using high-pressure homogenizer. The efficiency of the used isolation processes was studied by optical microscopy (OM), transmission electron microscopy (TEM), atomic force microscopy (AFM), and testing the tensile properties (wet and dry) of nanopaper sheets made from the nanofibers. In addition, opacity and porosity of nanopaper sheets made after different processing steps were investigated. The microscopy studies showed that the processes used resulted in nanofibers with diameters ranging from 3.5 to 60?nm. The results indicated that main isolation of nanofibers took place during refining using the ultrafine grinding process, while high-pressure homogenization resulted in smaller and more homogeneous size of nanofibers. Nanopaper sheets made from bagasse showed better wet and dry tensile strength properties than those made of rice straw.     

Response of a rising 2-year-old natural Piedmont upland stand to fertilization

Hardwood stands in the southern U.S. are often regenerated naturally following clearcutting, with little or no silvicultural intervention in the early stages of stand development. Fertilizer was applied to a young naturally regenerating stand in order to evaluate the effectiveness of nutrient addition as a silvicultural tool in recently clearcut stands and to better understand the ecological relationships between site fertility and stand development. The study was installed on a rising 2-year-old naturally regenerated mixed pine-hardwood stand in the Hill Demonstration Forest in the Piedmont region (Durham County) of North Carolina. Fertilizer treatments were control, N, N + P, and N + P + K (at 200 kg N per ha, 50 kg P per ha and 100 kg K per ha). On a whole stand basis, increased growth rates were observed for trees on N + P and N + P + K plots. Fertilizer treatments did not affect total stand density, but the density of loblolly pine significantly decreased in N + P plots compared to the Control. The density of stems of stump origin also increased in plots receiving N + P. Density of sweetgum (Liquidambar styraciflua) significantly increased and hickory (Carya spp.) density decreased with the application of N + P. Dominant hardwood species with the exception of yellow-poplar (Liriodendron tulipifera) responded with an increase in height to only N + P fertilizer treatments. Yellow-poplar increased in groundline diameter, height and mean tree volume index with the application of N + P. Loblolly pine (Pinus taeda) responded to N + P + K fertilizer treatment with an increase in height, diameter and volume index over the Control. There was no growth response among treatments for the 16 largest trees per species per plot, with the exception of red oak (Quercus rubra) which responded with an increase in height in N + P plots. Projected growth responses were modeled on a whole stand level and indicate that the use of N + P fertilizer may be an effective silvicultural instrument to increase growth, accelerate stand development, and shorten rotation length.     

Laboratory and environmental decay of wood–plastic composite boards: flexural properties

The flexural properties of wood–plastic composite (WPC) deck boards exposed to 9.5 years of environmental decay in Hilo, Hawaii, were compared to samples exposed to moisture and decay fungi for 12 weeks in the laboratory, to establish a correlation between sample flexural properties and calculated void volume. Specimens were tested for flexural strength and modulus, both wet and dry, at 23°C and 52°C. Some specimens degenerated to only 15% of original flexural strength. UV radiation had no impact on flexural properties of field-exposed boards; loss occurred mainly on the side opposite to the sun-exposed surface. The mechanism of the aging process on colonization of WPC by fungi was examined and is consistent with development of slow crack growth in the polyethylene matrix combined with wood decay by fungi. Wood particle decay, moisture, and elevated temperature were the major factors causing composite degradation, indicated by accumulation of voids and a severe decrease in flexural properties. To simulate long-term field impact (including decay) on WPC flexural properties in the laboratory, conditioning of specimens in hot water for an extended period of time is required. Exposure to water (70°C/5 days) was adequate for simulating long-term composite exposure in Hawaii of 4?×?15?×?86 mm³ specimens.