Genital sensory field: enlargement by estrogen treatment in female rats

Recordings of neuronal activity in the pudendal, genitofemoral, and pelvic nerves indicate that the sensory fields of these three nerves are the perineum, the caudal abdomen, and the vagino-cervical area and rectum, respectively. The sensory field of the pudendal nerve was significantly larger in estrogen-treated ovariectomized female rats than in uninjected controls. This effect of estrogen was not mediated by pudendal efferents.     

Long-term winter cover cropping effects on corn (Zea mays L.) production and soil nitrogen availability

 This study was conducted to determine effects of long-term winter cover cropping with hairy vetch, cereal rye and annual ryegrass on soil N availability and corn productivity. From 1987 to 1995, with the exception of the first year of the study, the cover crops were seeded each year in late September or early October after the corn harvest and incorporated into the soil in late April or early May. Corn was seeded 10 days to 2 weeks after the cover crop residues had been incorporated, and N fertilizer was applied as a side-dressing at rates of 0, 67, 134, or 201 kg N ha^–1 each year. While the average annual total N input from the above-ground biomass of the cover crops was highest for hairy vetch (72.4 kg N ha^–1), the average annual total C input was highest for cereal rye (1043 kg C ha^–1) compared with the other cover crops. Hairy vetch was the only cover crop that significantly increased pre-side-dressed NO₃ ^–-N (N_i) corn biomass and N uptake at 0 N. At an N fertilizer rate of 134 kg N ha^–1 or higher, the cover crops had a minimal effect on corn biomass. This indicated that even after 9 years of winter cover cropping, the effect of the cover crops on corn growth resulted primarily from their influence on soil N availability. The amount of available N estimated from the cover crops (N_ac) was significantly correlated with relative corn biomass production (r ²=0.707, P<0.001). The total amount of available N, comprising N_ac and N added from fertilizer (N_f), was strongly correlated (r ²=0.820, P<0.001)) with relative corn biomass production. The correlation was also high for the available N comprising N_i and N_f (r ²=0.775, P<0.001). Although cereal rye and annual ryegrass did not improve corn biomass production in the short term, they benefited soil organic N accumulation and gradually improved corn biomass production compared with the control over the long term. Received: 10 August 1999     

Properties of polyclonal, monoclonal, and recombinant antibodies recognizing the organophosphorus pesticide chlorpyrifos-ethyl

A rabbit polyclonal antiserum and two murine monoclonal antibodies recognizing the organophosphorus pesticide chlorpyrifos-ethyl were produced. The two hybridoma cell lines were then used as sources of immunoglobulin genes for the generation of recombinant scFv antibodies in Escherichia coli. The two scFvs showed either similar or improved limits of detection in an ELISA when compared with the monoclonal antibodies. Cross-reactivity studies showed that all of the antibodies were specific toward the chlorinated aromatic ring. Furthermore, scFv gene sequences were linked directly to sequences coding for either a c-Myc tag, a His-tag, or alkaline phosphatase. The fusion products generated were functional, and their properties were determined. The problems associated with producing scFvs and scFv derivatives for detection of pesticide residues from hybridoma are addressed and discussed.     

Tracks of cosmic rays in plastics

Cosmic ray nuclei have been observed with the use of plastic trackdetecting solids in satellites and high-altitude balloon flights. Nuclear emulsions in the stacks of plastic sheets allowed the positive identification of cosmic raynuclei as light as nitrogen. The most striking new information was the failure to observe relativistic iron nuclei, a result which has led to an advance in the understanding of track registration criteria.