Characterization of monoclonal antibodies against fowl poxvirus

Vaccines for the prevention of fowl pox in chickens and turkeys have been available for more than five decades. However, in recent years outbreaks have occurred in several previously vaccinated chicken flocks. Presumably, fowl poxviruses (FPVs) antigenically different from the attenuated vaccine strains are responsible for such occurrences. In support of this concept, we previously detected minor antigenic changes in field isolates based on comparative immunoblotting with polyclonal anti-FPV serum. Realizing the need for antibodies specific against the dominant antigens of FPV, monoclonal antibodies (MAbs) were produced by immunizing mice with either a field strain of FPV or a pigeon poxvirus, currently used for vaccination. Three hybridoma clones producing MAbs reacting with a specific FPV protein were selected from a total of 83 clones. In immunoblots, two of the MAbs, P1D9 and P2H10, recognized an antigen with an apparent molecular weight varying from 39 to 46 kD, depending on the FPV strain. The third MAb, P2D4, reacted with an approximately 80-kD protein, regardless of which FPV isolate was tested. Immunofluorescent staining with P1D9 and P2D4 revealed that these MAbs react with intracytoplasmic antigens in FPV-infected cells.     

Evaluation of a commercially available ELISA kit for detection of antibodies to Anaplasma marginale and Anaplasma centrale in cattle in Australia and Zimbabwe

A newly available competitive inhibition ELISA kit for the serological diagnosis of anaplasmosis was evaluated in Australia and Zimbabwe. In Australia the performance of the test was compared with the card agglutination test (CAT).The assay was evaluated using negative sera collected from Anaplasma-free herds, positive sera from experimentally infected cattle and sera from Anaplasma marginale-endemic herds. The sensitivity and specificity of the ELISA in Australia were 100 % and 83,3 %, respectively, and the sensitivity and specificity of the CAT were both 100%. The agreement between the ELISA and CAT in the sera from endemic herds was 86,4 % (kappa = 0,718). The specificity of the ELISA in Zimbabwe was 100%. No meaningful estimate of sensitivity was possible in Zimbabwe because few known positive sera were available for testing, but all eight known positive sera that were available were clearly positive. We conclude that the ELISA is a useful alternative to the CAT for epidemiological studies.The ELISA kits have advantages over the CAT in that the ELISA is more robust and reagents are better standardized, but the kits are expensive.     

Response of lemongrass (Cymbopogon flexuosus) under different levels of irrigation on deep sandy soils

The growth and herbage and oil production of East Indian lemongrass (Cymbopogon flexuosus) in response to different levels of irrigation water (IW) [0.1, 0.3, 0.5, 0.7, 0.9, 1.1, 1.3 and 1.5 times cumulative pan evaporation (CPE)] were evaluated on deep sandy soils at the research farm of the Central Institute of Medicinal and Aromatic Plants, Lucknow, from 1991 to 1993. In general, an increment in the level of irrigation increased the plant height up to 0.7 IW:CPE ratio. The response of irrigation levels on tiller production of lemongrass differed with the season of harvest. Maximum tillers/clump during the 2nd, 3rd, 6th and 7th harvests were in response to irrigation levels 0.9, 0.5, 0.7 and 0.7 IW:CPE ratio, respectively. Oil content had an inverse relationship with the levels of irrigation, specially during the 1st, 2nd, 5th and 6th harvests. Significantly higher herb and essential oil yields were recorded at 0.7 IW:CPE ratio, irrespective of season of harvest. The maximum total herb (22.79 t/ha in first year and 33.11 t/ha in second year) and oil (146.2 l/ha in the first year and 205.3 l/ha in the second year) yields were recorded at 0.7 IW:CPE ratio. The quality of oil with respect to the major chemical constituents (Citral-a, Citral-b and geraniol) was not changed. At the optimum level of irrigation (0.7 IW:CPE ratio) the water used by lemongrass was 118.2 cm for first year and 123.8 cm for the second year. Water-use efficiency was found to be higher (1.66 l oil/ha-cm) in the second year than the first year (1.23 l oil/ha-cm). For optimum yield potential of lemongrass on deep sandy soils of sub-tropical climate, the crop received 17 irrigations in the first year and 14 irrigations in the second year of harvests. Irrigations were made during the dry winter and summer months. Received: 15 April 1999     

Variations in soil microbial biomass and N availability due to residue and tillage management in a dryland rice agroecosystem

Seasonal changes in the levels of soil microbial biomass C (MBC) and N (MBN), N-mineralization rate and available-N concentration were studied in rice–barley supporting tropical dryland (rainfed) agroecosystem under six combinations of tillage (conventional, minimum and zero tillage) and crop residue manipulation (retained or removed) conditions. Highest levels of soil MBC and MBN (368–503 and 38.2–59.7 μg g⁻¹, respectively) were obtained in minimum tillage residue retained (MT+R) treatment and lowest levels (214–264 and 20.3–27.1 μg g⁻¹, respectively) in conventional tillage residue removed (CT−R, control) treatment. Along with residue retention tillage reduction from conventional to zero increased the levels of MBC and MBN (36–82 and 29–104% over control, respectively). The proportion of MBC and MBN in soil organic C and total N contents increased significantly in all treatments compared to control. This increase (28% in case of C and 33% N) was maximum in MT+R and minimum (10% for C and N both) in minimum tillage residue removed (MT−R) treatment. In all treatments concentrations of N in microbial biomass were greater at seedling stage, thereafter these concentrations decreased drastically (21–38%) at grain-forming stage of both crops. In residue removed treatments, N-mineralization rates were maximum during the seedling stage of crops and then decreased through the crop maturity. In residue retained treatments, however, N-mineralization rates were lower than in residue removed treatments at seedling stage of both crops. At grain-forming stage in all instances the N-mineralization rates in residue retained treatments considerably exceeded the rates in corresponding residue removed treatments. Tillage reduction and residue retention both increased the proportion of organic C and total N present in soil organic matter as microbial biomass. Microbial immobilization of available-N during the early phase of crops and its pulsed release later during the period of greater N demand of crops enhanced the degree of synchronization between crop demand and N supply. The maximum enhancement effects were recorded in the minimum tillage along with residue retained treatment. In the dryland agroecosystem studied, two management practices in combination proved more advantageous than either practice alone in maintaining soil fertility levels. For soil fertility amelioration in dryland agroecosystems with least dependence upon chemical fertilizer input, post-harvest retention of about 20 cm shoot biomass (accounting for 25–40% aboveground biomass) of previous crop and its incorporation in soil through minimum tillage in the succeeding crop is suggested, especially in the case of cereal.     

Evaluation of solid-phase chemiluminescent enzyme immunoassay, enzyme-linked immunosorbent assay, and latex agglutination tests for screening toxoplasma IgG in samples obtained from cats and pigs.

Serum samples from cats and pigs were analyzed by the solid-phase chemiluminescent enzyme immunoassay (SPCEI), enzyme-linked immunosorbent assay (ELISA), and indirect latex agglutination (ILA) methods. The SPCEI and ILA methods accurately analyzed Toxoplasma IgG (T-IgG) in both clinical and spiked samples from pigs and cats. The ELISA method accurately analyzed T-IgG in spiked samples from cats and pigs or clinical samples from pigs, but it did not accurately analyze T-IgG in clinical samples from cats. The antibody used in the ELISA kit did not cross-react with cat T-IgG. The SPCEI method that uses a stand-alone automated analyzer provided quantitative analysis, whereas the ELISA and ILA methods provided qualitative or, at best, semiquantitative analysis of T-IgG. The SPCEI and ELISA methods were rapid (60-90 minutes for 30 samples), whereas the ILA method required 13-15 hours for 30 samples. Although the three methods accurately distinguished positive from negative samples, the ILA method yielded many weakly positive results that were not confirmed by either the ELISA or SPCEI method. Thus, the indirect agglutination tests may give nonspecific responses at lower T-IgG concentrations.     

Genotypic basis of response to saliniity stress in some crosses of spring wheat Triticum aestivum L.

Wheat genotypes HD 2009, WH 157 and Kh 375 and their six F₁ crosses were evaluated for grain yield, biological yield and 1,000 grain weight under four levels of salinity (ECe 2.1, 6.2, 8.5 and 10.6 dS m^-1) in lysimeter type microplots. Parents Kh 375, WH 157 and HD 2009 were tolerant, moderately tolerant and sensitive to salinity, respectively. Reciprocal differences for salinity tolerance occurred for grain yield and 1,000 grain weight. The sensitive parent response was partially dominant whereas the salinity tolerant parent showed partial dominance for yield potential. Salinity tolerance and yield potential appeared to be controlled by different gene complexes. The cross Kh 375 × HD 2009 should provide transgressive segregants combining high yield potential with high salt tolerance. This revised version was published online in July 2006 with corrections to the Cover Date.     

Comparison of Raw Starch Hydrolyzing Enzyme with Conventional Liquefaction and Saccharification Enzymes in Dry‐Grind Corn Processing

In a conventional dry‐grind corn process, starch is converted into dextrins using liquefaction enzymes at high temperatures (90–120°C) during a liquefaction step. Dextrins are hydrolyzed into sugars using saccharification enzymes during a simultaneous saccharification and fermentation (SSF) step. Recently, a raw starch hydrolyzing enzyme (RSH), Stargen 001, was developed that converts starch into dextrins at low temperatures (<48°C) and hydrolyzes dextrins into sugars during SSF. In this study, a dry‐grind corn process using RSH enzyme was compared with two combinations (DG1 and DG2) of commercial liquefaction and saccharification enzymes. Dry‐grind corn processes for all enzyme treatments were performed at the same process conditions except for the liquefaction step. For RSH and DG1 and DG2 treatments, ethanol concentrations at 72 hr of fermentation were 14.1–14.2% (v/v). All three enzyme treatments resulted in comparable ethanol conversion efficiencies, ethanol yields, and DDGS yields. Sugar profiles for the RSH treatment were different from DG1 and DG2 treatments, especially for glucose. During SSF, the highest glucose concentration for RSH treatment was 7% (w/v), whereas for DG1 and DG2 treatments, glucose concentrations had maximum of 19% (w/v). Glycerol concentrations were 0.5% (w/v) for RSH treatment and 0.8% (w/v) for DG1 and DG2 treatments.     

Comparison of Modified Dry‐Grind Corn Processes for Fermentation Characteristics and DDGS Composition

Three different modified dry‐grind corn processes, quick germ (QG), quick germ and quick fiber (QGQF), and enzymatic milling (E‐Mill) were compared with the conventional dry‐grind corn process for fermentation characteristics and distillers dried grains with solubles (DDGS) composition. Significant effects were observed on fermentation characteristics and DDGS composition with these modified dry‐grind processes. The QG, QGQF, and E‐Mill processes increased ethanol concentration by 8–27% relative to the conventional dry‐grind process. These process modifications reduced the fiber content of DDGS from 11 to 2% and increased the protein content of DDGS from 28 to 58%.