Input-Output Budgets of Inorganic Nitrogen for 24 Forest Watersheds in the Northeastern United States: A Review

Input-output budgets for dissolved inorganic nitrogen (DIN) are summarized for 24 small watersheds at 15 locations in the northeasternUnited States. The study watersheds are completely forested, free of recent physical disturbances, and span a geographical region bounded by West Virginia on the south and west, and Maine on the north and east. Total N budgets are not presented; however, fluxes of inorganic N in precipitation and streamwater dominate inputs and outputs of N at these watersheds. The range in inputs of DIN in wet-only precipitation from nearby National Atmospheric Deposition Program (NADP) sites was 2.7 to 8.1 kg N ha^-1 yr^-1 (mean = 6.4 kg N ha^-1 yr^-1; median = 7.0 kg N ha^-1 yr^-1). Outputs of DIN in streamwater ranged from 0.1 to 5.7 kg N ha^-1 yr^-1 (mean = 2.0 kg N ha^-1 yr^-1; median = 1.7 kg N ha^-1 yr^-1). Precipitation inputs of DIN exceeded outputs in streamwater at all watersheds, with net retention of DIN ranging from 1.2 to 7.3 kg N ha^-1 yr^-1 (mean = 4.4 kg N ha^-1 yr^-1; median = 4.6 kg N ha^-1 yr^-1). Outputs of DIN in streamwater were predominantly NO₃-N (mean = 89%; median = 94%). Wet deposition of DIN was not significantly related to DIN outputs in streamwater for these watersheds. Watershed characteristics such as hydrology, vegetation type, and land-use history affect DIN losses and may mask any relationship between inputs and outputs. Consequently, these factors need to be included in the development of indices and simulation models for predicting 'nitrogen saturation' and other ecological processes.     

Pentapeptide (proctolin) associated with an identified neuron

Individual neurons can be recognized and identified anatomically, physiologically, and biochemically in the insect central nervous system. Biochemical analyses of extracts prepared from one such identified neuron show it to be associated with a bioactive pentapeptide called proctolin. This peptide may be a neurotransmitter, and a preparation is established in which its physiological action can be studied at the cellular level.     

Chronic arthritis in goats caused by a retrovirus

A virus was isolated from an adult goat with chronic arthritis and shown to belong to the retrovirus group by electron microscopy and biochemical methods. Inoculation of the virus into cesarean-derived specific-pathogen-free goats' kids produced arthritic lesions similar to those in the spontaneous disease. Vrus was reisolated from the experimentally induced lesions.     

Clonal characteristics of experimentally induced "atherosclerotic" lesions in the hybrid hare

The female hybrid hare (Lepus timidus x Lepus europaeus) is heterozygous for electrophoretically separable, X-linked isoenzymes of glucose-6-phosphate dehydrogenase. The isoenzymes of this animal have been used as cellular markers in the study of the clonal origins of experimentally induced atherosclerotic lesions. Aortic lesions produced in the hybrid hare by feeding cholesterol and injuring the aortic wall with a catheter have been shown to have polyclonal characteristics and in this way are fundamentally different from atherosclerotic fibrous plaques in man.     

Native and renatured transfer ribonucleic acid

Transfer ribonucleic acid, isolated under conditions in which the original macromolecular structure is never denatured, is indistinguishable from transfer ribonucleic acid prepared by conventional methods involving denaturing steps. This finding is consistent with the absence of direct genetic control of the formation of macromolecular structure of transfer ribonucleic acid.     

Wood versus fossil fuel as a source of excess carbon dioxide in the atmosphere: a preliminary report

If the amounts of wood consumed in deforestation to increase agricultural land and as firewood in underindustrialized countries are added to the amount consumed by the money economies as forest products, the estimates of the net amount of wood removed from the biosphere in this century should be revised upward. The per capita ratio of the weight of carbon from net wood burned to the weight of carbon from fossil fuel burned in this century has been at least 0.1 and may have approached 1.0.     

Role of Na+/H+ exchange by interferon-gamma in enhanced expression of JE and I-A beta genes

The rapid transductional sequences initiated by interferon-gamma (IFN-gamma) on binding to its receptor regulate functional and genomic responses in many cells but are not well defined. Induction of macrophage activation is an example of such functional and genomic changes in response to IFN-gamma. Addition of IFN-gamma to murine macrophages, at activating concentrations, produced rapid (within 60 seconds) alkalinization of the cytosol and a concomitant, rapid influx of 22Na+. Amiloride inhibited the ion fluxes and the accumulation of specific messenger RNA for two genes induced by IFN-gamma (the early gene JE and the beta chain of the class II major histocompatibility complex gene I-A). The data indicate that IFN-gamma initiates rapid exchange of Na+ and H+ by means of the Na+/H+ antiporter and that these amiloride-sensitive ion fluxes are important to some of the genomic effects of IFN-gamma.