Impact of Cotton Production Systems on Management of Hoplolaimus columbus.

The effectiveness of selected cultural practices in managing the Columbia lance nematode, Hoplolaimus columbus, on cotton was evaluated in experiments in growers' infested fields. The effects of planting date, cotton cultivar, treatment with the growth regulator mepiquat chloride, and destruction of cotton-root systems after harvest on cotton-lint yield and population densities of H. columbus were studied. The yield of cotton cultivar Deltapine 50 was negatively related (P = 0.054) to initial population density of H. columbus whereas the yield of Deltapine 90 was not affected by preplant density of this nematode, indicating tolerance in Deltapine 90. Reproduction of this nematode did not differ on the two cultivars. Planting date and treatment with the growth regulator mepiquat chloride did not influence cotton yield in a consistent manner. Application of mepiquat chloride suppressed (P

Effects of Rate and Time of Application of Poultry Litter on Hoplolaimus columbus on Cotton.

Field experiments were conducted to evaluate the effect of soil-incorporated poultry litter on the population dynamics of Hoplolaimus columbus and cotton lint yield. Rates of poultry litter applied varied from 0.0 to 27.0 t/ha and were applied in December, February, or March. Time of application did not influence population densities of this nematode or cotton yield. The rate of poultry litter applied was negatively related to the population density of H. columbus at midseason, but not at other sampling dates. The lower midseason levels of this nematode corresponded with increases in cotton lint yield in all experiments. Cotton yield increases generally were linear with respect to the rate of litter applied, although the highest rates of litter applied did not always result in the greatest cotton yield. Poultry litter can be used effectively to supply nutrients to the crop and suppress damaging levels of H. columbus. Optimal rates of litter application were from 6.0 to 13.4 t/ha. Application of poultry litter at these rates, however, may exceed nutrient levels required for best management practices.

A novel role for the budding yeast RAD9 checkpoint gene in DNA damage-dependent transcription.

Cells respond to DNA damage by arresting cell cycle progression and activating several DNA repair mechanisms. These responses allow damaged DNA to be repaired efficiently, thus ensuring the maintenance of genetic integrity. In the budding yeast, Saccharomyces cerevisiae, DNA damage leads both to activation of checkpoints at the G1, S and G2 phases of the cell cycle and to a transcriptional response. The G1 and G2 checkpoints have been shown previously to be under the control of the RAD9 gene. We show here that RAD9 is also required for the transcriptional response to DNA damage. Northern blot analysis demonstrated that RAD9 controls the DNA damage-specific induction of a large 'regulon' of repair, replication and recombination genes. This induction is cell-cycle independent as it was observed in asynchronous cultures and cells blocked in G1 or G2/M. RAD9-dependent induction was also observed from isolated damage responsive promoter elements in a lacZ reporter-based plasmid assay. RAD9 cells deficient in the transcriptional response were more sensitive to DNA damage than wild-type cells, even after functional substitution of checkpoints, suggesting that this activation may have an important role in DNA repair. Our findings parallel observations with the Escherichia coli SOS system and suggest the existence of an analogous eukaryotic network coordinating the cellular responses to DNA damage.

Brainstem projections to the major respiratory neuron populations in the medulla of the cat.

Efferent and afferent connections of the dorsal and ventral respiratory groups in the medulla of the cat were mapped by axonal transport of wheat germ agglutinin conjugated to horseradish peroxidase. Injections of wheat germ agglutinin-horseradish peroxidase into the dorsal respiratory group and the three principal subdivisions of the ventral respiratory group (caudal, rostral, and Bötzinger Complex) revealed extensive interconnections between these regions and with a limited number of other brainstem neuron populations. Major neuron populations with efferent projections to the regions of the dorsal and ventral respiratory groups include the parabrachial nuclear complex (medial parabrachial, lateral parabrachial, and Kölliker-Fuse nuclei), subregions of the lateral paragigantocellular reticular nucleus, subregions of the lateral and magnocellular tegmental fields, inferior central and postpyramidal nuclei of the raphe, and sensory trigeminal nuclei. A previously unidentified neuron population with extensive efferent projections to the dorsal and ventral respiratory groups was found near the ventral surface of the rostral medulla; we refer to this group as the retrotrapezoid nucleus. The results suggest that the dorsal and ventral respiratory groups form an extensively interconnected neuronal system receiving convergent inputs from the same brainstem nuclear groups, consistent with the hypothesis that the dorsal and ventral groups are primarily sites for integration of sensory and premotor respiratory drive inputs. Neuron populations in the rostral ventrolateral medulla with projections to both the dorsal and ventral respiratory groups, particularly the retrotrapezoid nucleus and neighboring subregions of the lateral paragigantocellular reticular nucleus, are candidate sites for participation in respiratory rhythmogenesis or other critical functions of the brainstem respiratory control system such as intracranial chemoreception.

Is capacity for pleasure associated with executive career success?

Executives with a low capacity for pleasure were examined to determine if they evidence less occupational and social success than those with normal or high capacity. Data on pleasure capacity and depressive symptoms were collected from 88 senior executive officers, and scores were compared with independent ratings of career success. The 11% of executives with serious work-related or personal problems showed significantly higher pleasure scores than the rest. It is hypothesized that the relatively high pleasure scores of the least successful executives reflect a defensive process of denial or reaction formation rather than an excessively joyful personality trait. A longitudinal study of executives is proposed to clarify whether the high pleasure capacity scores of the least successful executives change situationally over time.