Comparison of spectroscopic techniques for the determination of Kjeldahl and ammoniacal nitrogen content of farmyard manure.

The feasibility of determining the nitrogen content of farmyard manure using infrared spectroscopy was investigated. Fifteen samples each of cattle, pig, and turkey manure were analyzed by three infrared techniques: Fourier transform mid-infrared (MIR), using attenuated total reflection (ATR); near-infrared reflectance (NIR-R); and near-infrared optothermal photoacoustic (NIR-OT). The near-infrared measurements were made at wavelengths determined respectively by four (NIR-OT) and five (NIR-R) band-pass filters. The total nitrogen (using the Kjeldahl method) and volatile (ammoniacal) nitrogen contents of all samples were measured by wet chemistry. Internally cross-validated (ICV) partial least-squares (PLS) regression was then used to obtain calibrations for the nitrogen content. The data sets obtained by each technique were treated separately. Within these sets, data from each manure type were treated both separately and combined: the best predictive ability was obtained by combining data from all three manure types. From the combined data set, the residual standard deviations and correlation coefficients for the ICV-predicted versus actual Kjeldahl nitrogen content were, respectively, 6772 mg/kg dry wt, 0.862 (MIR); 9434 mg/kg dry wt, 0.771 (NIR-OT); and 8943 mg/kg dry wt, 0.865 (NIR-R). For the ammoniacal nitrogen content, the residual standard deviations and correlation coefficients were 3869 mg/kg dry wt, 0.899 (MIR); 6079 mg/kg dry wt, 0.820 (NIR-OT); and 3498 mg/kg dry wt, 0.961 (NIR-R).

A rapid whole-blood immunoassay system.

A new immunoassay system has been developed which allows the detection of circulating antigens, antibodies or drugs in whole blood without specialized personnel or equipment. This is achieved by the use of bispecific reagents, which comprise specific antibodies or antigens that are coupled to a non-agglutinating antierythrocyte antibody. Within two minutes, these reagents cause specific agglutination of a patient's own red cells in samples that contain the relevant analyte. Levels of low molecular weight haptens also can be measured by the use of an indirect, agglutination-inhibition assay. This simple immunoassay method would fulfil the needs of many physicians and Third-World countries and also has mass-screening and veterinary applications.

Genetic observations on the taxon Anopheles (Cellia) pharoensis Theobald (Diptera: Culicidae).

A photomap of the ovarian polytene chromosomes from Anopheles pharoensis is presented. The arrangement shown is that found in populations from Zululand, South Africa, and represents the arbitrary standard for the taxon. Two X-chromosome arrangements exist in samples from allopatric natural populations. Crosses between females homozygous for the inverted arrangement, Xa, and males carrying the standard arrangement, X+a, give F1 males that are sterile. Females from this cross, and both males and females from the reciprocal cross, are fertile. The simplest hypothesis is that the two X-chromosome arrangements mark two species within the taxon An. pharoensis Theobald. The practical implications are briefly discussed.

Fenitrothion (OMS 43) resistance in the taxon Anopheles culicifacies Giles.

Two colonies of the taxon Anopheles culicifacies Giles (one from Maharashtra State and one from Gujarat State, India) produced 28 and 64% mortality rates, respectively, on 1% fenitrothion for 2 hours. Six-hour exposures were required to achieve mortalities of greater than or equal to 96% in both colonies.

Unidirectional hybrid male sterility from crosses between species A and species B of the taxon Anopheles (Cellia) culicifacies Giles.

Crosses between species A females and species B males of the taxon Anopheles culicifacies give F1 males with undeveloped testes, reduced vasa deferentia, and apparently normal accessory glands. F1 males from the reciprocal cross, and F1 hybrid females from both reciprocal crosses are fertile, though their fertility is less than that of either parental species

Chromosomal evidence for sibling species of the malaria vector Anopheles (Cellia) culicifacies Giles.

The ovarian polytene chromosomes of adult Anopheles culicifacies from natural populations in Pakistan, India and Sri Lanka, and from four laboratory colonies (one from Pakistan and three from India) are compared with the published cytological map for this taxon. Two types of X-chromosome exist. One of these is identical with the published map; the other differs by two inversions. No autosome arm rearrangements are detected. A photomap is presented which documents the X-chromosome inversions. Both types of Xs are found in a natural population near New Delhi in the apparent absence of heterozygotes. This is interpreted as evidence for biologically distinct species within the taxon An. culicifacies Giles. The formal taxonomic and practical implications are briefly discussed.