Structural characterization of virion proteins and genomic RNA of human parainfluenza virus 3

The virion proteins and genomic RNA of human parainfluenza virus 3 have been characterized. The virion contains seven major and two minor proteins. Three proteins of 195 X 10(3) molecular weight (195K), 87K, and 67K are associated with the nucleocapsid of the virion and have been designated L, P, and NP, respectively. Three proteins can be labeled with [14C]glucosamine and have molecular weights of 69K, 60K, and 46K. We have designated these proteins as HN, F0, and F1, respectively. HN protein has interchain disulfide bonds, but does not participate in disulfide bonding to form homomultimeric forms. F1 appears to be derived from a complex, F1,2, that has an electrophoretic mobility similar to that of F0 under nonreducing conditions. A protein of 35K is associated with the envelope components of the virion and aggregates under low-salt conditions; this protein has been designated M. The genome of human parainfluenza virus 3 is a linear RNA molecule with a molecular weight of approximately 4.6 X 10(6).     

Specific Inhibition of the Cyanide-insensitive Respiratory Pathway in Plant Mitochondria by Hydroxamic Acids

Hydroxamic acids, R-CONHOH, are inhibitors specific to the respiratory pathway through the alternate, cyanide-insensitive terminal oxidase of plant mitochondria. The nature of the R group in these compounds affects the concentration at which the hydroxamic acids are effective, but it appears that all hydroxamic acids inhibit if high enough concentrations are used. The benzhydroxamic acids are effective at relatively low concentrations; of these, the most effective are m-chlorobenzhydroxamic acid and m-iodobenzhydroxamic acid. The concentrations required for half-maximal inhibition of the alternate oxidase pathway in mung bean (Phaseolus aureus) mitochondria are 0.03 mm for m-chlorobenzhydroxamic acid and 0.02 mm for m-iodobenzhydroxamic acid. With skunk cabbage (Symplocarpus foetidus) mitochondria, the required concentrations are 0.16 for m-chlorobenzhydroxamic acid and 0.05 for m-iodobenzhydroxamic acid. At concentrations which inhibit completely the alternate oxidase pathway, these two compounds have no discernible effect on either the respiratory pathway through cytochrome oxidase, or on the energy coupling reactions of these mitochondria. These inhibitors make it possible to isolate the two respiratory pathways and study their mode of action separately. These inhibitors also enhance an electron paramagnetic resonance signal near g = 2 in anaerobic, submitochondrial particles from skunk cabbage, which appears to be specific to the alternate oxidase and thus provides a means for its assay.     

The Respiratory Chain of Plant Mitochondria: XI. Electron Transport from Succinate to Endogenous Pyridine Nucleotide in Mung Bean Mitochondria

Energy-linked reverse electron transport from succinate to endogenous NAD in tightly coupled mung bean (Phaseolus aureus) mitochondria may be driven by ATP if the two terminal oxidases of these mitochondria are inhibited, or may be driven by the free energy of succinate oxidation. This reaction is specific to the first site of energy conservation of the respiratory chain; it does not occur in the presence of uncoupler. If mung bean mitochondria become anaerobic during oxidation of succinate, their endogenous NAD becomes reduced in the presence of uncoupler, provided that both inorganic phosphate (P_i) and ATP are present. No reduction occurs in the absence of P_i, even in the presence of ATP added to provide a high phosphate potential. If fluorooxaloacetate is present in the uncoupled, aerobic steady state, no reduction of endogenous NAD occurs on anaerobiosis; this compound is an inhibitor of malate dehydrogenase. This result implies that endogenous NAD is reduced by malate formed from the fumarate generated during succinate oxidation. The source of free energy is most probably the endogenous energy stores in the form of acetyl CoA, or intermediates convertible to acetyl CoA, which removes the oxaloacetate formed from malate, thus driving the reaction towards reduction of NAD.     

The Respiratory Chain of Plant Mitochondria. II. Oxidative Phosphorylation in Skunk Cabbage Mitochondria

Mitochondria were prepared from the spadices of skunk cabbage (Symplocarpus foetidus) whose respiratory rate with succinate and malate showed 15% to 30% sensitivity to cyanide inhibition, and which showed respiratory control by added ADP. The observed respiratory control ratios ranged from 1.1 to 1.4. The change in pH of the mitochondrial suspension was recorded simultaneously with oxygen uptake: alkalinization of the medium, expected for phosphorylation of ADP, coincided with the period of acceleration in oxygen uptake caused by addition of an ADP aliquot. The ADP/O ratios obtained were 1.3 for succinate and 1.9 for malate. In the presence of 0.3 mm cyanide, the ADP/O ratio for succinate was zero, while that for malate was 0.7. These results are consistent with the existence of an alternate oxidase which interacts with the flavoprotein and pyridine nucleotide components of the respiratory chain and which, in the presence of cyanide, allows the first phosphorylation site to function with an efficiency of about 70%. In the absence of respiratory inhibitors, the efficiency of each phosphorylation site is also about 70%. This result implies that diversion of reducing equivalents through the alternate oxidase, thereby bypassing the 2 phosphorylation sites associated with the cytochrome components of these mitochondria, occurs to a negligible extent during the oxidative phosphorylation of ADP or State 3.Addition of ADP or uncoupler to skunk cabbage mitochondria respiring in the controlled state or State 4, results in reduction of cytochrome c and the oxidation of the cytochromes b, ubiquinone and pyridine nucleotide. A site of interaction of ADP with the respiratory chain between cytochromes b and cytochrome c is thereby identified by means of the crossover theorem. Flavoprotein measured by fluorescence is also oxidized upon addition of ADP or uncoupler, but flavoprotein measured by optical absorbance changes becomes more reduced under these conditions. Depletion of the mitochondria by pretreatment with ADP and uncoupler prevents reduction of most of the fluorescent flavoprotein by succinate. These results indicate that skunk cabbage mitochondria contain both high and low potential flavo-proteins characterized by different fluorescence/absorbance ratios similar to those demonstrated to be part of the respiratory chain in mitochondria from animal tissues.     

PRENATAL CARE—A Group Psychotherapeutic Approach

It has been well established that “normal” pregnancy gives rise to much anxiety whose source is variable. When not adequately dealt with, the anxiety may masquerade in the guise of physical symptoms such as fatigue, dizziness, nausea and vomiting, or, more often, as disquieting emotional counterparts, like irritability and depression.A study was undertaken in the outpatient obstetrical department at U.C.L.A. utilizing a group psychotherapeutic approach. The results helped the patients and offered training to staff in dealing with emotional problems of pregnancy. Patients were seen in groups of seven, twice a month for one-hour sessions. Participating in each group were an obstetrical resident, a psychiatric resident and a nurse. The subject material was not selected beforehand. Groups were similar in that the expected time of delivery of the patients was approximately the same. Results of the study suggested that the much needed emotional support may be supplied in this way with little to no additional time expenditure on the part of the physician or nurse.