Phenological and physiological evaluation of first and second cropping periods of sorghum and maize crops

Environmental conditions influence phenology and physiological processes of plants. It is common for maize and sorghum to be sown at two different periods: the first cropping (spring/summer) and the second cropping (autumn/winter). The phenological cycle of these crops varies greatly according to the planting season, and it is necessary to characterize the growth and development to facilitate the selection of the species best adapted to the environment. The aim of this study was to characterize phenological phases and physiological parameters in sorghum and maize plants as a function of environmental conditions from the first cropping and second cropping periods. Two parallel experiments were conducted with both crops. The phenological characterization was based on growth analyses (plant height, leaf area and photoassimilate partitioning) and gas exchange evaluations (net assimilation rate, stomatal conductance, transpiration and water-use efficiency). It was found that the vegetative stage (VS) for sorghum and maize plants was 7 and 21 days, respectively, longer when cultivated during the second cropping. In the first cropping, the plants were taller than in the second cropping, regardless of the crop. The stomatal conductance of sorghum plants fluctuated in the second cropping during the development period, while maize plants showed decreasing linear behaviour. Water-use efficiency in sorghum plants was higher during the second cropping compared with the first cropping. In maize plants, in the second cropping, the water-use efficiency showed a slight variation in relation to the first cropping. It was concluded that the environmental conditions as degree-days, temperature, photoperiod and pluvial precipitation influence the phenology and physiology of both crops during the first and the second cropping periods, specifically cycle duration, plant height, leaf area, net assimilation rate, stomatal conductance and water-use efficiency, indicating that both crops respond differentially to environmental changes during the growing season.     

Use of monoclonal antibodies against human HLA II antigens for the detection of bovine B lymphocytes and macrophages]

The crossreactivity of mouse monoclonal antibodies (MoAbs) (Tab. I) prepared against human HLA-DR and HLA-DP antigens was studied in various bovine cells: lymphocytes from lymph nodes and peripheral blood, adherent (B) and nonadherent (T) lymphocytes, monocytes, granulocytes and platelets. In the immunofluorescence test, MoAbs Bra13, Bra14, Bra20, Bra22, Bra30, Bra70, HL-38 reacted with bovine B lymphocytes and monocytes, but not with other tested cells (Tab. III, IV). These antibodies, except Bra22, were positive with B lymphocytes in the complement dependent cytotoxic test (Tab. II). The similarity of the bovine antigens and HLA-DR antigens determined by used MoAbs was also proved by immunoblotting. Monoclonal antibodies Bra38 and BraFB6 did not react with the bovine cells and separated antigens. The epitope (HLA-DR) recognized by the antibody Bra38 is probably absent in cattle. The presence of HLA-DP analogue determined by the antibody BraFB6 has not been confirmed. The crossreactive MoAbs could be used for the detection of B lymphocytes and macrophages in veterinary immunology.     

Direct and Residual Contributions of Symbiotic Nitrogen Fixation by Legumes to the Yield and Nitrogen Uptake of Maize (Zea mays L.) in the Nigerian Savannah

Field experiments were conducted to determine the direct and residual contributions of legumes to the yield and nitrogen (N) uptake of maize during the wet seasons of 1994 and 1995 at the University Farm, Abubakar Tafawa Balewa University, Bauchi, Nigeria, located in the Northern Guinea savannah of Nigeria. Nodulating soybean, lablab, green gram and black gram contributed to the yield and N uptake of maize either intercropped with the legumes or grown after legumes as a sole crop. Direct transfer of N from the nodulating soybean, lablab, green gram and black gram to the intercropped maize was 24.9–28.1, 23.8–29.2, 19.7–22.1 and 18.4–18.6 kg N ha^–1, respectively. However, the transfer of residual N from these legumes to the succeeding maize crop was 18.4–20.0, 19.5–29.9, 12.0–13.7 and 9.3–10.3 kg N ha^–1, respectively. Four years of continuous lablab cropping resulted in yields and N uptake of the succeeding maize crop grown without fertilizer N that were comparable to the yields and N uptake of the succeeding maize crop supplied with 40–45 kg N ha^–1 and grown after 4 years of continuous sorghum cropping. It may therefore be concluded that nodulating soybean, lablab, green gram and black gram may be either intercropped or grown in rotation with cereals in order to economize the use of fertilizer N for maize production in the Nigerian savannah.     

Population variability of some quantitative characters in Argas polonicus larvae (Acarina: Argasidae)

The nature of variability of quantitative morphometrical characters was studied in larvae of two local populations of Argas (Argas) polonicus Siuda, Hoogstraal, Clifford et Wassef, 1979 collected in Czechoslovakia and Poland. Statistically significant differences in five quantitative characters studied, in which the larvae of both wild populations differed from one another, disappeared during three generations of laboratory rearing. The variability of these characters was lower in laboratory populations than in field collected ticks. The results of hybridization experiments and analysis of variability of larvae of individual populations and parental pairs suggest that rather adaptive than genetic variation is involved. The genetic component of the variation is inferior and is expressed probably by dominant relations between alleles of the same locus, or by different types of non-allelic interactions.     

Neurological Manifestations of Niemann-Pick Disease Type C in Cats

Seven Domestic shorthair cats with a lysosomal storage disorder analogous to human Niemann-Pick disease type C, from a breeding colony were studied to characterize the neurological manifestations of this disorder. Affected cats were identified by means of liver biopsies at 4 to 6 weeks of age. Neurological examinations were performed at 2 week intervals from the onset of clinical signs. All cats displayed signs referrable to the cerebellum, with a subtle intention tremor noticed initially at 8 to 12 weeks of age; the disease was rapidly progressive. The tremor became more pronounced, menace response was lost, and severe dysmetria and ataxia developed. Three cats also had signs referrable to other areas of the central nervous system. Cats died or were euthanized between 12 and 43 weeks of age. Pathological findings included accumulation of substrate within neurons throughout the central nervous system, and axonal spheroid formation. The clinical and pathological findings in these cats are comparable to those in the human form of the disease.     

Diagnosis of sarcocystosis in sheep using the indirect fluorescence test and ELISA]

The indirect fluorescent antibody test (IFAT) was compared with the enzyme-linked immunosorbent assay (ELISA) for the detection of specific antibodies to Sarcocystis sp. A set of 275 ovine blood samples was examined by both reactions. Cystozoites of Sarcocystis gigantea were used as the corpuscular antigen for the IFAT. For the diagnostics of sarcocystosis by the ELISA technique used the sandwich test of the antibody titration with a soluble antigen which was also prepared from S. gigantea macrocysts. Our studies confirmed that this antigen did not cross-react with Toxoplasma gondii. Titre 40 was determined as the limit one for the IFAT and titre 80 for the ELISA; which was confirmed by the direct detection of cysts in the muscles (Svobodová, 1989). The results of both methods are shown in Table I. 76.7% of the blood samples reacted positively in the IFAT and 83.6% in the ELISA. These methods were found to be suitable and can be utilized for the intravital routine diagnostics.     

Antibodies to bovine serum albumin in swine sera: implications for false-positive reactions in the serodiagnosis of African swine fever

Antibodies to bovine serum albumin were detected in swine sera by use of an immunoblotting technique. Such sera had false-positive reactions, as determined by results of African swine fever virus serodiagnostic techniques when bovine serum albumin was a contaminant in the soluble cytoplasmic antigen obtained from infected cells cultured in the presence of bovine serum. The soluble cytoplasmic antigen obtained from cell cultures infected with African swine fever virus in the presence of porcine serum did not react with the false-positive sera and, therefore, was used for African swine fever virus serodiagnostic methods, with 0% false-positive results.     

Divergent selection for shape of growth curve in Japanese quail. 1. Responses in growth parameters and food conversion.

1. HG and LG quail lines selected for high and low relative weight gain between 11 and 28 d of age (RG11-28), respectively, and an unselected C line were compared. Mature body weight of both selected lines was held at that of the C line. Progeny of generation 6 were used for analysis. 2. Divergent selection for RG11-28 brought about opposite changes in the growth rates shortly after hatching. 3. Parameters of the Richards function were used to describe the growth curve. The largest differences between HG and LG lines occurred in age (t+) and body weight (y+) at the inflection point of the growth curve (on average for both sexes 28% and 20%, respectively). For HG quail, the parameter t+ was 5 d later than that for LG quail (18.6 vs 14.1 d for males and 20.6 vs 15.6 d for females, respectively), and consequently the parameter y+ was greater (90.3 vs 84.0 g for males and 104.5 vs 96.1 g for females, respectively). The shape of the growth curve expressed by the y+/A ratio was substantialy different for HG and LG quail (44.8% vs 39.6% for males and 43.5% vs 36.8% for females, respectively). 4. The food/gain ratios for the fattening period (3 to 35 d of age) were 3.21, 3.47 and 3.34 for the HG, LG and C lines, respectively. The HG quail started to utilise food more efficiently than the LG quail as early as 10 to 14 d, that is, at the age when their relative growth rate first became greater. 5. The relative deviations of the HG and LG lines from the C line are discussed.     

Growth patterns of two lines of Angus cattle selected using predicted growth parameters.

Linear functions of body weight and condition score at weaning and 18 mo of age were used to predict the mature weight (A) and maturing rate (k) parameters of an asymptotic growth model of Angus cows at the Subtropical Agricultural Research Station, Brooksville, FL. From 1981 through 1988 a heavy-mature-weight line (Line A) and a rapid-maturing line (Line K) were selected based on predicted A and k values. Linear contrasts (A-K) of least squares means for weight at fixed ages indicated that the weight difference between lines increased from birth to maturity during the period of the study. Animals from Line A were heavier (P less than .01) at all ages. A negative response in maternal ability, relative to increased growth potential of their calves, seems to have occurred in the cows of Line A. Mature weight was reached at approximately 4.5 yr of age in Line K and at approximately 5.5 yr in Line A. Brody's three-parameter and Richards' four-parameter functions were fitted to 2,855 quarterly weights of cows, from birth to 6.5 yr of age, to estimate the average growth curve for each line. Brody's model gave better estimates of weights from 18 mo to maturity, but the asymptotic residual mean squares were slightly higher because early weights were overestimated. Linear and nonlinear regression analyses of weight-age data and comparisons of degree of maturity at different premature ages showed differences in the growth patterns of the two lines selected for early predicted values of A and k.     

Teratogenicity testing of BI 58 EC (38% dimethoate) in chicken embryos with special respect to degradation of the active ingredient.

The insecticide formulation BI 58 EC was tested for teratogenicity in chicken embryos, with particular reference to degradation of the active ingredient (dimethoate) after the treatment of embryonated eggs. The pesticide was diluted in water to a concentration level of 0.8%, and the emulsion was injected into the air space in a volume of 0.1 ml/egg, or hen's eggs were treated by the immersion technique. Residues of dimethoate were measured in the samples on days, 13, 15 and 19 of the incubation of chicken embryos, and morphological examinations were performed simultaneously. Analytical chemistry data indicated a slower degradation of dimethoate in embryos after the immersion of eggs, and cyllosis was remarkable in this group among the sporadic developmental anomalies. The liver tissues of both treated groups exhibited severe fatty infiltration.