Chemical and microbial diagenesis of humic matter in freshwaters

The importance of microbial activity in changing the chemical properties of humic material in brown waters was measured as a function of pH, acid neutralization capacity (ANC), and pK_a affinity spectrum from brownwater samples kept in aquaria and sterile flasks. Changes to the humic matter in non-sterile microcosms caused increases in pH and ANC and loss of strong organic acid pK_a sites. Microbial activity was shown to be the main contributor to a decrease in acidity of humic material as samples kept under sterile conditions showed less change than non-sterile ones. Microbial processes were shown to be mostly due to sessile organisms on the walls of the aquaria and in sediments. Our data suggest that acid-base properties of brownwaters can be modified based on residence times, as well as by temperature in their basins. Assuming similar starting humic materials, microbial degradation may account for the lower acidity measured in lakes and large rivers, compared to headwaters.     

Cardiolipin polyspecific autoreactivity in two broadly neutralizing HIV-1 antibodies

The design of a human immunodeficiency virus-1 (HIV-1) immunogen that can induce broadly reactive neutralizing antibodies is a major goal of HIV-1 vaccine development. Although rare human monoclonal antibodies (mAbs) exist that broadly neutralize HIV-1, HIV-1 envelope immunogens do not induce these antibody specificities. Here we demonstrate that the two most broadly reactive HIV-1 envelope gp41 human mAbs, 2F5 and 4E10, are polyspecific autoantibodies reactive with the phospholipid cardiolipin. Thus, current HIV-1 vaccines may not induce these types of antibodies because of autoantigen mimicry of the conserved membrane-proximal epitopes of the virus. These results may have important implications for generating effective neutralizing antibody responses by using HIV-1 vaccines.     

Decreased nitrogen rates and irrigation effect on celery yield and internal quality

The effect of decreased nitrogen rates (90, 60 and 30 kg N/ha) with and without irrigation on celery yield quantity and internal quality were studied in field experiments in 1993 and 1994. The decreased nitrogen rates reduced yields in both years. In the dry and warm conditions of 1994 nitrogen × irrigation interaction was clearly observed; irrigation increased yield more at higher nitrogen rates than at lower nitrogen rates. In the rainy conditions of 1993 irrigation did not effect the yield level.On the other hand, in both years, decreased nitrogen rates increased dry matter, vitamin C and dietary fiber contents, and nitrogen had a minor effect on total sugar content. In 1994 alpha- and beta carotene and thiamin were also analyzed but nitrogen had no effect on them. Irrigation increased dry matter and total sugar contents at the two lowest nitrogen rates in 1994, but decreased vitamin C contents in both years. There was also slight evidence that irrigation might decrease alpha- and beta-carotene and thiamin contents.     

Family composition of Douglas-fir nursery stock as influenced by seed characters,mortality, and culling practices

Changes in family composition during nursery production were evaluated by following individual seeds and seedlings of 36 wind-pollinated Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco) families sown in mixture in two operational nurseries in western Washington and Oregon. Families differed significantly in emergence and in percent of seedlings culled for being too small. However, differences were small enough that family composition was largely unaffected. The observed changes in family composition did not markedly reduce genetic diversity and did not affect the genetic gain that may be expected from an improved population. The plantable nursery stock was, for the most part, representative of the composition of families originally sown.     

The diagnosis of adrenal cortical function in animals using hormone analysis

This paper describes the use of hormone analysis in the diagnosis of adrenal cortex dysfunction in the dog, cat and horse. Analytical problems concerning the determination of corticosteroid levels are discussed and the pathology of adrenal dysfunction is briefly presented. The paper focuses on the problems in establishing physiological norms for adrenal function based on the established assays. Own experiences and other reported data are referred to.