Proposal for Naming Host Cell-Derived Inserts in Retrovirus Genomes

We propose a system for naming inserted sequences in transforming retroviruses (i.e., onc genes), based on using trivial names derived from a prototype strain of virus.     

Intravascular and extracellular volumes in the diabetic rat

Simultaneously measured intravascular (IVV) and extracellular (ECV) volumes in diabetic rats have not been reported. We evaluated IVV and ECV in alloxan induced diabetic rats which were either untreated (DU) or received supplemental daily insulin (DI) for three months. Two separate groups of control rats were comparably weight matched to each experimental group. Radio-iodinated (125-I) human serum albumin (RISA) and 35-S sulfate were used to determine IVV and ECV respectively. In DU rats, values for IVV and ECV expressed as a percentage of body weight were 9.3±0.5% and 35±2% respectively; both are significantly larger than the volumes measured in control rats (IVV=6.6±0.2%, p^<0.001 and ECV=28±1%, p<0.01). DI rats had volumes (IVV=6.0±0.3% and ECV=24±3%) which were not significantly different than those of control rats (IVV=5.7±0.1% and ECV=22±1%). Thus, untreated diabetic rats had increased IVV and ECV while diabetic rats that received insulin were normovolemic despite the presence of hyperglycemia.     

Metabolic activation of hexamethylmelamine and pentamethylmelamine by liver microsomal preparations

Incubation of [¹⁴C]-ring labeled hexamethylmelamine and pentamethylmelamine with rat and mouse liver microsomal preparations results in metabolic activation of both drugs as measured by covalent binding of radiolabel to acid-precipitable microsomal macromolecules. Covalent binding is dependent on viable microsomes, NADPH, and molecular oxygen. Binding of HMM (280 pmol/mg protein/15 min) was approximately 5 times greater than that observed for PMM (60 pmol/mg protein/15 min), and represents 0.22% of incubated material. Similar results were found with [¹⁴C]-methyl labeled substrates. Pretreatment with phenobarbital increased covalent binding while addition of SKF 525-A, addition of glutathione, or incubation in an 80% carbon monoxide atmosphere reduced covalent binding.     

Life history variation in the black swallowtail butterfly

Summary Research into local (neighborhood) competition has heretofore focused on either natural populations of long-lived woody plants or artifical populations of herbaceous annuals. To explore the usefulness of these techniques for herbaceous perennials, 1 applied them to 11 natural populations of 4 species of violet (Viola blanda, V. pallens, and V. incognita, alone and with V. adunca). Ramet density ranged from 132 to 508 per square meter. The analysis tried to account for the size of each ramet (expressed as the number of leaves) using information on the number, size, and angular aggregation of neighboring plants in three concentric annuli (0–3, 3–6, and 6–9 cm). Simple rank correlations between leaf number and these measures of local competition were usually of the expected sign, but were consistently significant in only two of the populations (1 pallens and 1 incognita). No significant correlations were of the wrong sign. When the spatial independent variables were combined into multiple regression equations they accounted for between 5 and 59% of the total variance in leaf number. The equations were best in predicting individual size in the Newfoundland populations of V. incognita which had the greatest range in individual size. Total plant density appeared unrelated to predictive success.The neighborhood competition approach can be applied to natural populations of herbaceous perennials, but low density, inaccurate measures of plant performance and microvariation in site quality limit its usefulness. In particular, it seems impossible to determine the mechanism by which neighbors exert their competitive effects with this approach.     

Daily energy expenditure and the cost of activity in a free-living mammal

Summary Antelope ground squirrels (Ammospermophilus leucurus, 80–100 g) began surface activity 1.0–1.5 h after sunrise and ended it 0.5–1.25 h before sunset throughout the year near Barstow, California. Daily energy expenditure (DEE) of free-living animals measured with doubly labeled water (H³H¹⁸O) decreased from 1,340 kJ kg^-1 d^-1 in April to 970 in October. Resting metabolic rates (RMR) of freshly-captured, fed, ground squirrels varied through the year (22.1 J g^-1 h^-1 in August, 19.1 in January) but most of the change in DEE could be explained by differences in thermoregulatory costs between seasons. The ground squirrels had lower rates of resting metabolism at night (15.3J g^-1 H^-1) than during the day.The cost of activity (calculated by subtracting 24 h resting costs from total DEE during August and October, periods when thermoregulatory costs were negligible) was 550 kJ kg^-1 d^-1 in August and October. Thus, activity accounted for about 50% of the total DEE. The mean rate of energy expenditure during the activity period, calculated as activity cost (kJ d^-1) divided by activity time (h d^-1), then plus RMR, was about 3xRMR. This multiplication factor may be useful as an estimator of foraging costs or in estimating DEE from time budgets.     

Normetanephrine and octopamine involvement in normacromerine biosynthesis in Coryphantha macromeris var. runyonii

Administration of [7-³H]normetanephrine to living Coryphantha macromeris var. runyonii resulted in the formation of labeled normacromerine     

Volatile oils of mature and juvenile leaves of Juniperus horizontalis: Chemosystematic significance

Comparison of 39 terpenoids between young (juvenile) foliage and mature (adult) foliage from naturally growing plants of Juniperus horizontalis revealed no significant differences. Canonical variate analysis of the terpenoids of J. scopulorum and J. virginiana along with the mature foliage of J. horizontalis and co-plotting juvenile foliage showed a slight loosening of the J. horizontalis group but not enough to blur taxonomic distinctions. These results stand in sharp contrast with the previous work on J. scopulorum and appear to be due to the indeterminant growth pattern seen in J. horizontalis.     

Synthesis and biological activity of brassinolide and its 22β,23β-isomer: Novel plant growth-promoting steroids

Brassinolide (2α,3α,22α, 23α-tetrahydroxy-24α-methyl-B-homo-7-oxa-5α-cholestan-6-one), a novel plant growth-promoting steroid isolated from rape pollen, and its hitherto unknown 22β, 23β-isomer were synthesized from a C-24 epimeric 60:40 mixture of 22-dehydrocampesterol (24α-methyl) and brassicasterol (24β-methyl) from oysters. The method of synthesis favored the formation of the 22β, 23β-isomer by better than 4:1. Comparative plant growth-promoting capabilities of brassinolide, both natural and synthetic, and its three side chain $\text{cis}$-glycolic isomers in the bean second internode bioassay showed that the natural and synthetic brassinolides were equally active and caused splitting of the internode at the 0.1 μg level. The least active was the 22β,23β-isomer of brassinolide. The isomers with the 22α, 23α and 24β, and the 22β, 23β and 24β configurations were highly active and were required at about 10 times the concentration of brassinolide to cause the same physiological response. In the bean first internode bioassay, an auxin-induced growth test system which employs isolated bean plant segments, the isomer with 22β, 23β and 24β configuration caused a greater response than brassinolide. Two of the four tetrahydroxy ketones obtained in the synthesis of the isomers were also active in both assays.     

Stereochemical aspects of forcing special substrate hydrazides to behave either as electrophiles or as nucleophiles during catalysis by crude papain

Restriction of hydrazides of N-blocked amino acids mainly to electrophilic action, in acylating crude papain, has been achieved by means of a large amount of aniline, with formation of insoluble anilides of N-acylamino acids. Similarly, nucleophilic behavior, on the part of a hydrazide, has been promoted by introducing a large proportion of an N-acylamino acid to produce an insoluble N¹,N²-diacylhydrazine. Achiral, chiral and racemic hydrazides and their corresponding N-acylamino acids were utilized in the study. Among the more informative combinations of reactants were Z-dl-alanine hydrazide with aniline and then with Z-glycine. A stereospecific response in the former situation produced Z-l-alanine anilide. In the latter case, a stereoselective interaction produced Z-Gly-NHNH-lAla-Z more rapidly than Z-Gly-NHNH-d-Ala-Z. The final incubation period yielded an optically pure D product. Differences in stereochemical control have been delineated in terms of different spatial aspects for interactions at the S and S′ subsites of sulfhydryl proteolytic enzymes. A racemic reactant encountered firm stereospecificity as an electrophile at the S subsite but only modest stereoselectivity as a nucleophile at the S′ subsite. The ready availability of crude papain allows an effective procedure for the synthesis of substantial quantities of diacylhydrazines.     

Membrane assembly from purified components. I. Isolated M13 procoat does not require ribosomes or soluble proteins for processing by membranes

The coat protein of coliphage M13 is an integral protein of the host-cell cytoplasmic membrane prior to its assembly into virions. It is initially synthesized as procoat, a soluble precursor with a 23 amino acid leader sequence at its amino terminus. ³⁵S-labeled procoat accumulates during an in vitro translation reaction that contains ³⁵S-methionine and RNA from M13-infected cells. Radiochemically pure procoat has been isolated from in vitro translation reactions by extraction into an organic solvent and gel filtration through Sephadex LH-60. Radiochemically pure procoat can be used as substrate in rapid and quantitative assays for leader peptidase and for leader peptide hydrolase, an enzyme that degrades the leader peptide after its release from procoat. Procoat solubility, digestion by leader peptidase and processing by membranes are affected by the presence of Mg²⁺ ion. Isolated procoat is soluble in water at low ionic strength and mildly alkaline pH as well as in detergent solutions. It is cleaved to coat protein by purified E. coli leader peptidase and by inverted E. coli inner-membrane vesicles. These properties of the purified procoat mirror those of the procoat in crude extracts. This suggests that there are no other soluble components that are necessary for the assembly of procoat into the membrane and its conversion to coat; specifically, it provides powerful evidence that protein synthesis is not involved.