Biophysical and Biochemical Heterogeneity of Purified Hepatitis B Antigen

Hepatitis B antigen of the D (a+, d+, y-) subtype was purified from plasma of apparently healthy persons and from hepatitis patients. The original samples contained 20- and 42-nm particles and tubular forms (20-nm diameter). Ultracentrifugation during the purification procedure yielded pellets which were then treated at pH 2.4. Both the large, 42-nm Dane particles and the tubular forms were lost during the acid treatment of the pelleted particles, yielding a preparation containing a mixture of particles approximately 20 and 25 nm in diameter. This difference in size was substantiated in that two distinct molecular weights were calculated from high-speed equilibrium data, 3.6 x 10(6) and 4.5 x 10(6). Further heterogeneity was observed in that hepatitis B antigenic activity was present in purified particles with an isoelectric pH of 4.0 and also in those with a pH of 4.4. No significant differences were observed in the gross amino acid composition of purified antigen obtained from plasma of three different persons. (125)I-labeled, purified antigen was found to contain six distinct polypeptides with molecular weights ranging from 10,000 to 39,000.     

Genetic and evolutionary relationships among Asian Macaques

Published gene frequency data, checked for consistency of allele definitions across laboratories and for comparability of geographically identical samples, were pooled into a data set containing frequencies at nine loci for each of 20 populations that encompassed 10 macaque species. Genetic distances were calculated by the methods of Kidd and Cavalli-Sforza (1974). These distances were used to construct phylogenetic trees and to evaluate the relationships between divergence times and effective population sizes. Inter-and intraspecific genetic distances and the groupings defined by phenetic tree analyses support Fooden’s (1976) classification of the genus Macacainto four species groups. A paleozoogeographical model of Asia including the known times of major sea-level changes allows us to explain Macacainto four species groups. A paleozoogeographical model of Asia including the known times of major sea-level changes allows us to explain qualitatively the inferred evolutionary relationships among macaque species. Many assumptions are required in order to estimate the variables necessary in the quantitative prediction of genetic differences for a comparison between any two populations. Examination of those assumptions demonstrates the need for more accurate genetic as well as paleozoogeographic information. An erratum to this article is available at .     

Uncoupling of mitochondrial oxidative phosphorylation by thallium.

The mechanism of integration of λ$\text{bio}$ll, which is deleted of all the known λ recombination genes, was studied using $\text{bio}$ deleted hosts as recipients. The presence of $\text{rec}$BC DNase and $\text{exo}$I in the recipient cells affected the fate of λ$\text{bio}$ll DNA. In nine of ten $\text{imm}\text{λ}{}^{\mathrm{+}}$ transductants, insertion of the λ$\text{bio}$ll genome took place somewhere between J and N and the remaining one had abnormally permuted prophage λ. In this lysogen (#42), the sequence of prophage genes was similar to that of vegetative phage λ. The properties of lysogen #42 were compared with those of other lysogens.     

Structure and Composition of a Small Particle Prepared from a Simian Adenovirus.

Mayor, Heather D. (Baylor University College of Medicine, Houston, Tex.), Richard M. Jamison, Liane E. Jordan, and Joseph L. Melnick. Structure and composition of a small particle prepared from a simian adenovirus. J. Bacteriol. 90:235-242. 1965.-When tissue-culture fluids infected with simian adenovirus SV15 are examined in an electron microscope, either as fresh harvests or after treatment with Genetron, typical mature adenovirus particles are found. These are 65 to 70 mmu in diameter, with an icosahedral capsid built from 252 capsomeres. Also present is a population of small polyhedral particles approximately 20 mmu in diameter. These small particles can be separated from the mature virions by ultrafiltration or density gradient centrifugation. The small particles have a density of 1.43 in cesium chloride. They contain protein and double-stranded deoxyribonucleic acid. They appear to possess cubic symmetry of the icosahedral type, with a coat composed of 12 subunits each at the vertex of an icosahedron.     

Extracellular suppression allows mating by pheromone-deficient sterile mutants of Saccharomyces cerevisiae

MAT alpha haploids with mutations in the STE13 or KEX2 gene, and MATa haploids with mutations in the STE6 or STE14 gene, do not mate with wild-type cells of the opposite mating type. We found that such mutants were able to mate with partners that carry mutations (sst1 and sst2) that cause cells to be supersensitive to yeast mating pheromone action. Mating ability of MAT alpha ste13 and MAT alpha kex2 mutants could also be restored by adding normal MAT alpha cells to mating mixtures or by adding just the appropriate purified pheromone (alpha-factor). Therefore, the mating deficiencies caused by the ste13 and kex2 lesions, and by inference, the ste6 and ste14 mutations, appear to result only from secretion of an insufficient amount of pheromone or a nonfunctional pheromone.     

Voltage-Dependent Behavior of Delayed-Firing Neurons in the Rat <Emphasis Type="Italic">Substantia Gelatinosa</Emphasis>

Upon application of a long-lasting rectangular stimulus, neurons of the substantia gelatinosa (SG) display three main types of intrinsic firing behavior, tonic, adapting, and delayed onset. The electrical landmark of delayed-firing neurons (DFNs), i.e., a significant delay before initiation of action potentials (APs), is believed to result from activation of subthreshold A-type K⁺ current (K_A). We checked out this hypothesis by comparing the voltage dependence of the firing delay with steady-state inactivation of K_A in spinal cord slices of 3- to 5-week-old rats. The delay strongly decreased with membrane depolarization and disappeared at ~ –60 mV; herewith the discharge pattern was transformed to either a tonic or an adapting one. This correlated well with inactivation of K_A recorded in a whole-cell mode in low-Cl^– intracellular solution; inactivation was nearly complete at –60 mV (voltage of half-maximum inactivation, V _1/2 ~ –74.5 mV). Unexpectedly, it was found that filling the cells with high-Cl^– solution, to minimize the liquid junction potential, produced at least a 10 mV-difference between voltage dependences of the firing delay and K_A inactivation; the latter shifted toward negativity (V _1/2 ~ –88.3 mV). The results suggest that the K_A and its inactivation properties determine the appearance and voltage dependence of the firing delay in SG neurons; the apparent influence of intracellular Cl^– on inactivation properties needs further investigation.     

Salivary gland branching morphogenesis: a quantitative systems analysis of the Eda/Edar/NFκB paradigm

Background  

Ectodysplasin-A appears to be a critical component of branching morphogenesis. Mutations in mouse Eda or human EDA are associated with absent or hypoplastic sweat glands, sebaceous glands, lacrimal glands, salivary glands (SMGs), mammary glands and/or nipples, and mucous glands of the bronchial, esophageal and colonic mucosa. In this study, we utilized Eda ^Ta (Tabby) mutant mice to investigate how a marked reduction in functional Eda propagates with time through a defined genetic subcircuit and to test the proposition that canonical NFκB signaling is sufficient to account for the differential expression of developmentally regulated genes in the context of Eda polymorphism.     

Method for detecting viruses in aerosols

A simple method with poliovirus as the model was developed for recovering human enteric viruses from aerosols. Filterite filters (pore size, 0.45 micron; Filterite Corp., Timonium, Md.) moistened with glycine buffer (pH 3.5) were used for adsorbing the aerosolized virus. No virus passed the filter, even with air flow rates of 100 liters/min. Virus recovery from the filter was achieved by rapid elution with 800 ml of glycine buffer, pH 10. The virus in the primary eluate was reconcentrated by adjusting the pH to 3.5, adding AlCl3 to 0.0005 M, collecting the virus on a 0.25-micron-pore Filerite disk (diameter, 25 mm) and and eluting with 6 ml of buffer, pH 10. With this method, virus could be detected regularly in aerosols produced by flushing when 3 X 10(8) PFU of poliovirus were present in the toilet bowl. Poliovirus-containing fecal material from two of four infants who had recently received oral polio vaccine also yielded virus in the aerosols when feces containing 2.4 X 10(7) to 4.5 X 10(7) PFU of virus had been added to the toilet bowl. Persons infected with a variety of natural enteric viruses are known to excrete this amount of virus in their daily stools.     

The association between sociodemographic,hormonal, tubo-ovarian factors and bacterial count in Chlamydia and Mycoplasma infections with infertility

Aim: To determine if there is an association between the Chlamydia and Mycoplasma infections with socio-demographic and clinical factors, and also with infertility. Methods: We conducted a study on 100 infertile married women and 100 control group, and collected data on the socio-demographic, hormonal and tubo-ovarian factors. The results of the endocervical swabs were analyzed for Mycoplasma and Chlamydia infection, the bacterial counts were also determined. Results: The percentage positivity to infection was significantly more among the infertile group compared to the control group, and also significantly more among the age group <30 years old. The positivity for infection with Chlamydia and/or Mycoplasma was significantly correlated with age, history of irregular menstruation, and history of previous abortion. Further sub-analysis of the infertile group showed that positivity to Chlamydia and/or Mycoplasma infection was significantly correlated to hormonal factors, ovarian factors, irregular menstruation, and previous abortion. Regression analysis showed that hormonal, ovarian factors, and irregular menstruation were the most significant factors in the positivity to Chlamydia and Mycoplasma infection. Bacterial count was significantly correlated with age, history of irregular menstruation, and history of previous abortion. Conclusion: Infection to Chlamydia and Mycoplasma is associated to younger age (?30 years old), and occurs in the infertile women. There is an interplay between infection in younger women, irregular menstruation, hormonal, and tubo-ovarian factors with infertility. Bacterial count was significantly correlated with age, history of irregular menstruation, and history of previous abortion.