Impact of High Night‐Time and High Daytime Temperature Stress on Winter Wheat

High temperature is a major environmental factor that limits wheat (Triticum aestivum L.) productivity. Climate models predict greater increases in night‐time temperature than in daytime temperature. The objective of this research was to compare the effects of high daytime and high night‐time temperatures during anthesis on physiological (chlorophyll fluorescence, chlorophyll concentration, leaf level photosynthesis, and membrane damage), biochemical (reactive oxygen species (ROS) concentration and antioxidant capacity in leaves), growth and yield traits of wheat genotypes. Winter wheat genotypes (Ventnor and Karl 92) were grown at optimum temperatures (25/15 °C, maximum/minimum) until the onset of anthesis. Thereafter, plants were exposed to high night‐time (HN, 25/24 °C), high daytime (HD, 35/15 °C), high daytime and night‐time (HDN, 35/24 °C) or optimum temperatures for 7 days. Compared with optimum temperature, HN, HD and HDN increased ROS concentration and membrane damage and decreased antioxidant capacity, photochemical efficiency, leaf level photosynthesis, seed set, grain number and grain yield per spike. Impact of HN and HD was similar on all traits. Greater impact on seed set, grain number and grain yield per spike was observed at HDN compared with HN and HD. These results suggest that HN and HD during anthesis cause damage of a similar magnitude to winter wheat.     

Estimation of Deposition Velocities for 85Sr, 131I, 137Cs on Spinach,Radish and Beans Leaves in a Tropical Region Under Simulated Fallout Conditions

Poly dispersive aerosols of SrCl₂, NaI, CsCl having a size distribution of 2.33 m (Activity Median Aerodynamic Diameter, [AMAD]) with a geometric standard deviation of 1.83 m are used for the determination of deposition velocity for ⁸⁵Sr, ¹³¹I and ¹³⁷Cs aerosols on tropical spinach (Spinicia olericia), radish (Raphanous sative) and beans (Phasolous valugeries) plant leaves. The experiments were carried out in a specially designed exposure chamber to simulate deposition under accidental releases of radioactivity in tropical environment. The rates of particles deposition are expressed as a function of plant surface area and of plant dry weight. The deposition velocities obtained are in the range of 10^–6 to 10^–7 m/s. These values differ significantly from those in temperate regions. The lower values for deposition velocities (v _g) for the tropical environment is attributed due to high humidity. Therefore, the deposition of suspended aerosols on leaf surfaces caused by impaction and Brownian diffusion becomes slower in tropical environment and resulted into lower value of deposition velocities.     

Effect of water management on dry seeded and puddled transplanted rice: Part 2: Water balance and water productivity

Labour and water scarcity in north west India are driving researchers and farmers to find alternative management strategies that will increase water productivity and reduce labour requirement while maintaining or increasing land productivity. A field experiment was done in Punjab, India, in 2008 and 2009 to compare water balance components and water productivity of dry seeded rice (DSR) and puddled transplanted rice (PTR). There were four irrigation schedules based on soil water tension (SWT) ranging from saturation (daily irrigation) to alternate wetting drying (AWD) with irrigation thresholds of 20, 40 and 70 kPa at 18–20 cm soil depth. There were large and significant declines in irrigation water input with AWD compared to daily irrigation in both establishment methods. The irrigation water savings were mainly due to reduced deep drainage, seepage and runoff, and to reduced ET in DSR. Within each irrigation treatment, deep drainage was much higher in DSR than in PTR, and more so in the second year (i.e. after 2 years without puddling). The irrigation input to daily irrigated DSR was similar to or higher than to daily irrigated PTR. However, within each AWD treatment, the irrigation input to DSR was less than to PTR, due to reduced seepage and runoff, mainly because all PTR treatments were continuously flooded for 2 weeks after transplanting. There was 30–50% irrigation water saving in DSR-20 kPa compared with PTR-20 kPa due to reduced seepage and runoff, which more than compensated for the increased deep drainage in DSR. Yields of PTR and DSR with daily irrigation and a 20 kPa irrigation threshold were similar each year. Thus irrigation and input water productivities (WP_I and WP_I+R) were highest with the 20 kPa irrigation threshold, and WP_I of DSR-20 kPa was 30–50% higher than of PTR-20 kPa. There was a consistent trend for declining ET with decreasing frequency of irrigation, but there was no effect of establishment method on ET apart from higher ET in DSR than PTR with daily irrigation. Water productivity with respect to ET (WP_ET) was highest with a 20 kPa irrigation threshold, with similar values for DSR and PTR. An irrigation threshold of 20 kPa was the optimum in terms of maximising grain yield, WP_I and WP_I+R for both PTR and DSR. Dry seeded rice with the 20 kPa threshold outperformed PTR-20 kPa in terms of WP_I through maintaining yield while reducing irrigation input by 30–50%.     

Mortality of the tobacco caterpillar,Spodoptera litura (F.), when treated withBacillus Thuringiensis combinations with boric acid and insecticides

Bacillus thuringiensis Berliner in combination with 0.1, 0.5, 1.0, 1.5 and 2% boric acid caused 100% mortality of the tobacco caterpillar,Spodoptera litura (F.), irrespective of instar, in a much shorter period (1.77 to 3.61 days) than with boric acid or the pathogen alone. The toxicity ofB. thuringiensis in combination with dicrotophos at 0.02 and 0.04%, with fenitrothion at 0.025 and 0.05%, or with dichlorvos at 0.01 and 0.05%, was enhanced.     

Genetic variation and phylogenetic relationships among Indian Citrus taxa revealed by DAMD-PCR markers

Genetic variation and phylogenetic relationships among 50 wild and cultivated accessions of 19 Indian Citrus genotypes were examined through comparison of Directed Amplification of Minisatellite DNA (DAMD) markers and morphological characters. DAMD-PCR analysis with four primers resulted in amplification of a total of 45 bands, of which 35 (78 %) were polymorphic. Morphometric evaluation using 76 morphological characters showed high level of variability ranging from 0.18 to 1.00 (avg 0.39), whereas the Jaccard’s coefficient values of genetic similarity calculated from DAMD data ranged from 0.41 to 1.00 (avg 0.68), indicating moderate genetic divergence among the accessions studied. UPGMA dendrograms generated separately from morphometric and DAMD data segregated all the accessions of Citrus into four main clusters, each containing a true basic species and their probable hybrids. The grouping of individual accessions/genotypes under respective species or cultivars in DAMD dendrogram was based purely on their genetic relationships rather than geographical origin. There was no absolute congruence between the data and dendrograms generated from morphometric and DAMD analyses. The study demonstrates the resolving power of DAMD markers for discrimination of individual genotypes of Citrus under its respective species, hybrid or cultivar groups and inferring their genetic and phylogenetic relationships as well. This is the first report on application of DAMD markers in Citrus.     

Diagnosis of paratuberculosis in goats by cell mediated immune response,conventional and molecular diagnostic techniques

In the present study efficacy of single intradermal Johnin test, acid fast staining of faecal smear and IS 900 faecal polymerase chain reaction tests was evaluated in 200 goats for detection of Mycobacterium avium subsp paratuberculosis. Two hundred goats comprising 150 goats from an organised farm in Trichur district and 50 goats reared under field condition at farmers premise from Malappuram district of Kerala state formed the study population. Faecal smear from all the 200 goats was stained by Ziehl–Neelsen acid fast stain and faecal polymerase chain reaction (PCR) specific for M. avium subsp paratuberculosis (MAP); IS 900 was performed on all samples. All the animals were subjected to single intradermal Johnin test. Out of 200 goats screened for paratuberculosis, six goats (3%), 11 goats (5.5%) and 42 goats (21%) were found positive by Ziehl–Neelsen acid fast staining of faecal smear, single intradermal Johnin test and IS 900 PCR respectively. Results of the present study indicate that amplification of IS 900 insertion element was the most specific and sensitive diagnostic detection method. Single intradermal Johnin test and Ziehl–Neelsen acid fast staining did not show any significant difference.     

Effects of feeding wet corn distillers grains with solubles with or without monensin and tylosin on the prevalence and antimicrobial susceptibilities of fecal foodborne pathogenic and commensal bacteria in feedlot cattle

Distillers grains, a coproduct of ethanol production from cereal grains, are composed principally of the bran, protein, and germ fractions and are commonly supplemented in ruminant diets. The objective of this study was to assess the effect of feeding wet distillers grains with solubles (WDGS) and monensin and tylosin on the prevalence and antimicrobial susceptibilities of fecal foodborne and commensal bacteria in feedlot cattle. Cattle were fed 0 or 25% WDGS in steam-flaked corn-based diets with the addition of no antimicrobials, monensin, or monensin and tylosin. Fecal samples were collected from each animal (n = 370) on d 122 and 136 of the 150-d finishing period and cultured for Escherichia coli O157. Fecal samples were also pooled by pen (n = 54) and cultured for E. coli O157, Salmonella, commensal E. coli, and Enterococcus species. Antimicrobial resistance was assessed by determining antimicrobial susceptibilities of pen bacterial isolates and quantifying antimicrobial resistance genes in fecal samples by real-time PCR. Individual animal prevalence of E. coli O157 in feces collected from cattle fed WDGS was greater (P < 0.001) compared with cattle not fed WDGS on d 122 but not on d 136. There were no treatment effects on the prevalence of E. coli O157 or Salmonella spp. in pooled fecal samples. Antimicrobial susceptibility results showed Enterococcus isolates from cattle fed monensin or monensin and tylosin had greater levels of resistance toward macrolides (P = 0.01). There was no effect of diet or antimicrobials on concentrations of 2 antimicrobial resistance genes, ermB or tetM, in fecal samples. Results from this study indicate that WDGS may have an effect on the prevalence of E. coli O157 and the concentration of selected antimicrobial resistance genes, but does not appear to affect antimicrobial susceptibility patterns in Enterococcus and generic E. coli isolates.     

Capillary wrinkling of floating thin polymer films

A freely floating polymer film, tens of nanometers in thickness, wrinkles under the capillary force exerted by a drop of water placed on its surface. The wrinkling pattern is characterized by the number and length of the wrinkles. The dependence of the number of wrinkles on the elastic properties of the film and on the capillary force exerted by the drop confirms recent theoretical predictions on the selection of a pattern with a well-defined length scale in the wrinkling instability. We combined scaling relations that were developed for the length of the wrinkles with those for the number of wrinkles to construct a metrology for measuring the elasticity and thickness of ultrathin films that relies on no more than a dish of fluid and a low-magnification microscope. We validated this method on polymer films modified by plasticizer. The relaxation of the wrinkles affords a simple method to study the viscoelastic response of ultrathin films.     

Specific mutations induced by triplex-forming oligonucleotides in mice

Triplex-forming oligonucleotides (TFOs) recognize and bind to specific duplex DNA sequences and have been used extensively to modify gene function in cells. Although germ line mutations can be incorporated by means of embryonic stem cell technology, little progress has been made toward introducing mutations in somatic cells of living organisms. Here we demonstrate that TFOs can induce mutations at specific genomic sites in somatic cells of adult mice. Mutation detection was facilitated by the use of transgenic mice bearing chromosomal copies of the supF and cII reporter genes. Mice treated with a supF-targeted TFO displayed about fivefold greater mutation frequencies in the supF gene compared with mice treated with a scrambled sequence control oligomer. No mutagenesis was detected in the control gene (cII) with either oligonucleotide. These results demonstrate that site-specific, TFO-directed genome modification can be accomplished in intact animals.     

Antibodies to the core protein of lymphadenopathy-associated virus (LAV) in patients with AIDS

Lymphadenopathy-associated virus ( LAV ), a human T- lymphotrophic retrovirus isolated from a homosexual man with lymphadenopathy, has been causally associated with acquired immunodeficiency syndrome (AIDS). A sensitive and specific radioimmunoprecipitation test was developed for the detection of antibodies to the major core protein of LAV , p25 (molecular weight 25,000). Antibody to LAV p25 was found in the serum of 51 of 125 AIDS patients, 81 of 113 patients with lymphadenopathy syndrome, 0 of 70 workers at the Centers for Disease Control (some of whom had handled specimens from AIDS patients), and 0 of 189 random blood donors. Of a group of 100 homosexual men from San Francisco whose serum was obtained in 1978, only one had antibody to LAV p25; in contrast, of a group of 50 homosexual men in the same community whose serum was obtained in 1984, 12 had antibodies to LAV p25.