Transformation in Staphylococcus aureus: role of bacteriophage and incidence of competence among strains.

When used in a helper phage capacity, phages 29, 52, 52A, 79, 80, 55, 71, 53, 83A, 85, 95, 96, phi11, and 80 alpha, all serological group B Staphylococcus phages, conferred competence for transformation to S. aureus 8325-4, a strain that does not normally become competent. Of the serological group A phages tested, only phage 3A showed significant competence-conferring activity. Phages 29, 55, 53, 83A, .85, 95, phi11, and 80 alpha showed an enhancement of competence-conferring activity if exposure to the cells occurred in the presence of nromal rabbit serum. All of the propagating strains for the Staphylococcus reference typing phages were rendered competent for transformation by exposure to at least one of these helper phages. The use of a helper phage to confer competence to S. aureus did not result in distortion of the genetic linkages observed in an inherently competent strain. Lysogenization by phages phi11 or 83A is shown not to be required for the expression of competence, and evidence is presented which indicates that competence in the inherently competent 8325 strain is due to a helper phage effect initiated by the adsorption to cells of phi11 virion parts [or phi11 particles in the case of the single lysogen 8325-4(phi11)] that have been liberated by prophage induction.     

Linkage analysis and the inheritance of arches in a Habbanite isolate.

A pedigree and linkage analysis was performed on a corrected version of the Habbanite pedigree 2 of Slatis et al. [1]. The trait "arch on any digit" was examined for major gene inheritance and possible linkage to several blood and serum group markers. The results confirm the proposed dominant major gene inheritance of this trait with almost complete penetrance. In addition, the analysis suggests linkage with the haptoglobin locus with evidence against linkage with Pl and Rhesus. These results are of particular interest in view of recently reported dermatoglyphic associations with haptoglobin.     

Studies on the size,location and turnover of calcium pools accessible to growing Tetrahymena cells

Tetrahymena pyriformis cells in the logarithmic phase of growth accumulate 2.5–3.75 times as much calcium per unit volume as is present in the growth medium. It appears that most of this calcium is stored in a non-ionic form, with approximately 30% existing in the cilia, near its site of action in effecting ciliary reversal. The exchange of extracellular ⁴⁵Ca²⁺ with the major internal pools is extremely rapid, exhibiting a $\text{t}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ of less than 0.5 h. Sites located on the cilia are responsible for 35–50% of Ca²⁺ influx, with the remainder entering through other positions on the cell surface.     

Lipid crystallization in senescent membranes from cotyledons

Lipid transition temperatures for rough and smooth microsomal membranes isolated from bean (Phaseolus vulgaris) cotyledon tissue at various stages of germination were determined by wide angle x-ray diffraction. The transition temperatures were established by recording diffraction patterns through a temperature series until a sharp x-ray reflection centered at a Bragg spacing of 4.15 Å and denoting the presence of crystalline lipid was discernible. For rough and smooth microsomes from 2-day-old tissue, the transitions occurred at 0 C and 3 C, respectively, indicating that at this early stage in the germination sequence the membrane lipid is entirely liquid-crystalline at physiological temperature. By the 4th day of germination, the transition temperatures had increased to 32 C for smooth microsomes and 35 C for rough microsomes, indicating that at 29 C, which was the growth temperature, portions of the membrane lipid were crystalline. During the later stages of germination, the transition temperature for smooth microsomes continued to rise through 44 C at day 7 to 56 C at day 9, by which time the cotyledons were extensively senescent and beginning to abscise. There was also a dramatic increase in the proportion of membrane lipid in the crystalline phase at 29 C. By contrast, the rough microsomes showed little change in transition temperature and only a slight increase in the proportion of crystalline lipid during this late period in germination. The data indicate that substantial amounts of the lipid is senescing membranes are crystalline even at physiological temperature. Moreover, there is a temporal correlation between the appearance of this crystallinity and loss of membrane function, suggesting that the two may be causally related.     

The onset of mammary extraction of plasma triglycerides and circulating levels of progesterone during lactogenesis in the cow and goat

In untreated cows and goats, the onset of mammary extraction of plasma triglyceride was sometimes detected several hours before parturition, prior to removal of secretion from the mammary glands by offspring and when circulating progesterone concentrations were low. In cows and goats that had secretion regularly removed from the mammary glands late in gestation, the onset of triglyceride extraction occurred up to several days before parturition, when circulating progesterone concentrations were moderately high (up to 3.9 ng/ml in the cow and 6.2 ng/ml in the goat).