Nucleoside phosphorylase 2 (Np-2) of mice

Isozyme patterns of nucleoside phosphorylase (NP) in 16 inbred strains, two recombinant inbred, one congenic, and three species of wild mice were studied. Evidence is provided for a genetic locus, Np-2, encoding an electrophoretic variant which is expressed exclusively in erythrocytes of certain inbred strains. This finding establishes the occurrence of genetic polymorphism of NP among inbred strains of mice. In addition, the Npla allele previously reported only in inbred strains has been observed in one of the species of wild mice (Mus musculus castaneus) studied.     

Alteration by methadone of catecholamine uptake and release in isolated rat adrenomedullary storage vesicles

Incubation of isolated rat adrenomedullary storage vesicles with methadone produced inhibition of ³H-epinephrine uptake and promotion of release of endogenous catecholamines. Neither effect was seen using morphine, nor could morphine antagonize methadone-induced catecholamine release, suggesting that these actions are not mediated by opiate receptors. Inhibition of uptake by methadone appeared to contain a competitive component with a lower Ki for methadone compared to the Km for ³H-epinephrine. Despite competitive inhibition by methadone, the maximal uptake capacity (analogous to Vmax) as determined by double-reciprocal plots, was increased by the drug, probably as a result of greater availability of intravesicular storage sites because of the drug-induced of release endogenous catecholamines. Agents which enhance or block catecholamine transport into vehicles had no effect on the catecholamine release by methadone, indicating that the latter is separable from the action on uptake. These alterations of catecholamine uptake and release may play a role in the effects of methadone on the adrenal medulla $\text{in vivo}$.     

The role of fire as a mineralizing agent in a Sierran coniferous forest

Summary The role of fire as an agent for mineralizing forest floor organic matter was investigated in a Sierra Nevada sequoia-mixed conifer forest. Soil chemical properties were determined in a series of small paired plots on and adjacent to burns done by the National Park Service in their control burn program. Total nitrogen, carbon, and cation exchange capacity were found to be significantly lower on burned plots, and phosphorus, calcium, magnesium, potassium, and pH were significantly higher on burned plots. The seasonal course of certain soil chemical properties was determined in a single set of larger plots. Total nitrogen, nitrate, ammonium, phophorus, and pH were shown to increase in the spring. It is concluded that fire is an effective but not a conservative mineralizing agent.     

Diagnosis and Treatment of Amanita Phalloides-Type Mushroom Poisoning: Use of Thioctic Acid

The number of cases of mushroom poisoning is increasing as a result of the increasing popularity of “wild” mushroom consumption. Amanitin and phalloidin cytotoxins found in some Amanita and Galerina species produce the most severe and frequent life-threatening symptoms of Amanita phalloidestype poisoning. Delay in onset of symptoms, individual susceptibility variation and lack of rapid and reliable identification have contributed to the significant morbidity and mortality of this type of poisoning.A rapid chromatographic assay for identifying the potent cytotoxins and apparently successful management using thioctic acid of two cases of A. phalloides-type mushroom poisoning are reported. All known cases of A. phalloides-type mushroom poisoning treated with thioctic acid in the United States are summarized.     

Incidence of aneuploidy in a human population

A population of 40,371 individuals consisting of every baby delivered at two Denver hospitals from 1964 to 1974 has been screened from aneuploidy of the sex chromosomes and chromosome 21. The pattern in time with which aneuploidy occurs suggests an epidemic component of the incidence superimposed on an approximately equal constant frequency. The epidemic incidence is most likely to be high for births from May to October, to persist for several consecutive years, and then to be absent for several consecutive years.     

Heterogeneity in the conformation of different protein fractions from the human erythrocyte membrane

We have isolated 5 families of proteins from human red blood cell membranes and characterized their secondary structure by ultraviolet circular dichroism measurements. The protein families were prepared by selective solubilization from ghosts under nondenaturing conditions. We find that the intact ghost has a mean α-helix fraction of 0.37, whereas a low-ionic-strength extract (bands 1, 2, 5, “spectrin”) has a substantially higher helix fraction, 0.55. Further extraction of the ghosts with para-chloromercuribenzoate yields bands 2.1, 4.1, 4.2, and 6; their helix content is only 0.17. Finally, the major intrinsic protein, band 3, was solubilized by a nonionic detergent. Its helix fraction is 0.38.     

The Genetics of Dopa Decarboxylase in DROSOPHILA MELANOGASTER I. Isolation and Characterization of Deficiencies That Delete the Dopa-Decarboxylase-Dosage-Sensitive Region and the α-Methyl-Dopa-Hypersensitive Locus

A detailed cytogenetic investigation of 16 overlapping deficiencies in the 36C-40A region on the left arm of the second chromosome (2L) in Drosophila melanogaster is reported. These deficiencies permit a localization of both the dopa-decarboxylase-dosage-sensitive region and the α-methyl-dopa-hypersensitive locus, l(2)amd, to the same region, 37B10-37C7.     

Net‐spinning caddisfly distribution in large regulated rivers

1. Most of the world's large rivers are dammed for the purposes of water storage, flood control, and power production. Damming rivers fundamentally alters water temperature and flows in tailwater ecosystems, which in turn affects the presence and abundance of downstream biota.
2. We collaborated with more than 200 citizen scientists to collect 2,194 light trap samples across 2 years and more than 2,000 river km. Samples contained 16,222 net‐spinning caddisfly (Hydropsyche) individuals across six species. We used these data to model the distribution of Hydropsyche throughout the Colorado River Basin in the western U.S.A. to identify the roles of water temperature, flows, and species‐specific morphology in determining aquatic species distributions throughout a large arid watershed that has been heavily altered by damming.
3. We predicted that water temperatures would determine Hydropsyche presence and abundance to a greater extent than diel variation in river stage associated with hydropower production. Among many species, adult female Hydropsychids are morphologically adapted to swim to deep‐water oviposition sites. We predicted that the presence of this ability would negate the otherwise deleterious effects of high stage change on caddisfly egg mortality.
4. We found that distributions of the two most widespread species, Hydropsyche occidentalis and Hydropsyche oslari (92% of total Hydropsyche captured), were both predicted by water temperatures. However, we also found that the abundance of H. oslari decreased by as much as 10‐fold as diel stage change increased, despite the presence of female morphological adaptations for deep‐water oviposition. We found sexual dimorphism and evidence for deep‐water swimming adaptations in 5/6 species.
5. Our results show that net‐spinning caddisflies have species‐specific responses to environmental variation and suggest that environmental flows designed to reduce diel stage change and destabilise water temperatures may improve habitat quality for these ubiquitous and important aquatic insects.