Behavioral hormoligosis in oviposition preference of Bemisia tabaci on cotton

The study on behavioral hormoligosis in oviposition preference in Bemisia tabaci (Genn.) on cotton was conducted, at Entomological Research Farm, Punjab Agricultural University (PAU), Punjab, India, during 2001 crop season and repeated in the same season. Multiple-choice test was followed for conducting the experiment. Quinalphos (250, 375, and 500), carbaryl (625, 938, and 1250), acephate (750, 1125, and 1500), endosulfan (438, 656, and 875), and fenvalerate (25, 38, and 50 g ai/ha) were repeatedly sprayed on potted plants of American cotton (var. LH-1556). The impact of these insecticides was evaluated in term of oviposition preference by B. tabaci to treated plants. Also, it investigated changes in biochemical components of treated cotton leaves and the correlation with oviposition preference. The results revealed that, fenvalerate treated plants were more preferred by whitefly for oviposition. Maximum number of eggs was observed on fenvalerate treated plants, 38, 50, and 25 g/ha (39.3, 37.3, and 36.1 eggs/leaf, respectively) followed by acephate 1500 g/ha (26.9 eggs/ leaf) compared with untreated control (14.1 eggs/leaf). Almost similar trend of results was observed in the repeated experiment. The results obtained from biochemical studies revealed that all the insecticidal treatments caused reduction in total sugars compared with untreated control except fenvalerate and low dose of quinalphos. All insecticides caused increase in total free amino acids and brought significant changes in total phenols and pH value of treated plants. These results have confirmed the behavioral hormoligosis in oviposition preference that induced by fenvalerate and acephate in B. tabaci, which may be one of the causes behind its resurgence on plants repeatedly treated with these insecticides.     

Evaluation of cell wall preparations for proteomics: a new procedure for purifying cell walls from Arabidopsis hypocotyls

Background  

The ultimate goal of proteomic analysis of a cell compartment should be the exhaustive identification of resident proteins; excluding proteins from other cell compartments. Reaching such a goal closely depends on the reliability of the isolation procedure for the cell compartment of interest. Plant cell walls possess specific difficulties: (i) the lack of a surrounding membrane may result in the loss of cell wall proteins (CWP) during the isolation procedure, (ii) polysaccharide networks of cellulose, hemicelluloses and pectins form potential traps for contaminants such as intracellular proteins. Several reported procedures to isolate cell walls for proteomic analyses led to the isolation of a high proportion (more than 50%) of predicted intracellular proteins. Since isolated cell walls should hold secreted proteins, one can imagine alternative procedures to prepare cell walls containing a lower proportion of contaminant proteins.     

Optimization of Agrobacterium-mediated transformation parameters for Melastomataceae spp. using green fluorescent protein (GFP) as a reporter

Agrobacterium-mediated transformation for both Melastoma malabathricum and Tibouchina semidecandra were optimized using green fluorescent protein (GFP) as a reporter. The binary vector pCAMBIA1304 harboring the modified green fluorescent protein (mgfp) gene driven by the CaMV 35S promoter was used. Parameters optimized were bacterial strain, bacterial concentration, pre-culture period, co-cultivation period, immersion time, acetosyringone concentration and wounding type. Results obtained were based on the percentage of GFP expression which was observed 3 days post-transformation. Agrobacterium tumefaciens strain LBA4404 and EHA105 at concentration 1 × 10⁷ cfu ml⁻¹ (OD_600nm 0.8) showed the highest virulence on M. malabathricum and T. semidecandra, respectively. Four days of pre-culture and 2 days of co-cultivation were optimum for M. malabathricum transformation, while 3 days of pre-culture and co-cultivation for T. semidecandra. Result also showed that 60 min of immersion and addition of 200 μM acetosyringone gave the highest percentage of positive transformants for both M. malabathricum and T. semidecandra. Mild wounding also significantly increased the efficiency of M. malabathricum transformation.     

Detection of African horsesickness (AHS) in recently vaccinated horses with inactivated vaccine in Qatar

Two 7-year old Arabian racing horses were reported to show typical AHS symptoms in Qatar and died shortly after. The horses had been vaccinated with formol inactivated vaccine approximately 10 days before the onset of the disease. Blood samples from these horses were collected and AHS virus isolated from one sample after intracerebral (i.c.) inoculation into suckling mice. The virus identity was confirmed by complement fixation test (CFT) using the virus antigen and reference type 9 of AHS virus hyperimmune serum. The serotype of the isolated virus was identified by serum neutralization test (SNT) using reference types of AHS virus. Two possibilities of the original source of this infection were suggested. The infection might be due first to the natural endemic occurrence of the virus in the country and secondly, to the presence of residual infectious virus in the inactivated vaccine.     

Wheat Seed Presoaking for Improved Germination

Seed presoaking improves wheat germination under marginal moisture conditions. The duration of seed presoaking was studied at The University of Arid Agriculture, Rawalpindi, using 10 wheat varieties. Seed presoaking beyond 12 h does not improve germination further, and beyond 21 h, germination rate is drastically reduced.     

Application of an airborne laser scanner to forest road design with accurate earthwork volumes

In this study we developed a forest road design program based on a high-resolution digital elevation model (DEM) from a light detection and ranging (LIDAR) system. After a designer has located the intersection points on a horizontal plane, the model first generates the horizontal alignment and the ground profile. The model precisely generates cross-sections and accurately calculates earthwork volumes using a high-resolution DEM. The model then optimizes the vertical alignment based on construction and maintenance costs using a heuristic technique known as tabu search. As the distance between cross-sections affects the accuracy of earthwork volume calculations, the results were examined by comparing them with the exact earthwork volume calculated by the probabilistic Monte Carlo simulation method. The earthwork volumes calculated by the Pappus-based method were similar to those calculated by the Monte Carlo simulation when the distance between cross-sections was within 10m. The model was applied to a high-resolution DEM from the LIDAR of Capitol Forest in Washington State, USA. The model generated a horizontal alignment, length 827m, composed of five horizontal curves. We examined the number of grade change points. The results indicated that tabu search found the best solution ($61.42/m) with five grade change points. This was composed of two vertical curves that almost followed the ground profile. As the accuracy of a high-resolution DEM from LIDAR increases, the model would become a useful tool for a forest road designer because it eliminates or at least reduces the time-consuming process of road surveys.