An Ectonucleotide ATP-diphosphohydrolase Activity in Trichomonas vaginalis Stimulated by Galactose and Its Possible Role in Virulence

This work describes the ability of living Trichomonas vaginalis to hydrolyze extracellular ATP (164.0 ± 13.9 nmol Pi / h × 107 cells). This ecto-enzyme was stimulated by ZnCl2, CaCl2 and MgCl2, was insensitive to several ATPase and phosphatase inhibitors and was able to hydrolyze several nucleotides besides ATP. The activity was linear with cell density and with time for at least 60 min. The optimum pH for the T. vaginalis ecto-ATPase lies in the alkaline range. ᴅ-galactose, known to be involved in adhesion of T. vaginalis to host cells, stimulated this enzyme by more than 90%. A comparison between two strains of T. vaginalis showed that the ecto-ATPase activity of a fresh isolate was twice as much as that of a strain axenically maintained in culture, through daily passages, for several years. The results suggest a possible role for this ecto-ATPase in adhesion of T. vaginalis to host cells and in its pathogenicity.

An Effective Strategy, Applicable toStreptococcus salivarius and Related Bacteria, To Enhance or Confer Electroporation Competence

ABSTRACT Despite the large number of techniques available for transformation of bacteria, certain species and strains are still resistant to introduction of foreign DNA. Some oral streptococci are among the organisms that can be particularly difficult to transform. We performed a series of experiments that involved manipulation of growth and recovery media and cell wall weakening, in which the electroporation conditions, cell concentration, and type and concentration of the transforming plasmid were varied. The variables were optimized such that a previously untransformable Streptococcus salivariusstrain, ATCC 25975, could be transformed reproducibly at a level of 105 transformants per μg of DNA. The technique was used to introduce a plasmid into other strains of S. salivarius, including a fresh isolate. Moreover, the same technique was applied successfully to a wide range of oral streptococci and other gram-positive bacteria.

Effects of storage time and temperature on amylopectin levels and oocyst production of Eimeria meleagrimitis oocysts

SUMMARYEimeria meleagrimitis oocysts were stored at 4, 22, 32 or 41·5 °C for up to 1 year. Decreases in amylopectin levels (measured as glucose) and viability (measured as oocyst production and mortality in turkeys) of the oocysts were generally related to the length of time in storage and the storage temperature. Oocysts assayed immediately after harvest contained 58·29 ± 0·75 μg of glucose/106 oocysts. When the oocysts were stored at 4 °C for 162 days, the amylopectin level decreased to 65% of the original level. In oocysts stored at 22, 32 and 41·5 °C, amylopectin declined to approximately 20% within 162, 76, and 41 days, respectively. Oocysts stored at 4 °C for 1 year produced more oocysts in turkeys than the original fresh isolate, but caused no mortality. Oocyst production from oocysts stored at 22 and 32°C decreased gradually until, after 9 and 7 months respectively, no patent infections were produced. Oocyst production from oocysts stored at 41·5 °C was markedly reduced within 1 month and was not detected after 4 months.

Eimeria maxima: a comparison of two laboratory strains with a fresh isolate

SummaryOocysts of the Weybridge and Houghton strains ofEimeria maximaand a fresh field isolate were similar and measured on average 30·9 × 22·4 μm. The Weybridge strain and the field isolate produced similar pathogenic effects in 6-week-old chickens, high doses causing 50–80% mortality and severe weight loss. The Houghton strain was slightly less pathogenic and few birds died but more oocysts were produced. With each strain, a single dose gave complete immunity to a light challenge with the homologous strain. Two or 3 immunizing doses gave complete immunity to a heavy homologous challenge but were not sufficient to protect against heterologous challenge.

The morphology of induced wall-defective variants of Streptococcus faecalis as studied by light and electron microscopy

Study by light microscopy of induced wall-defective variants of Streptococcus faecalis was undertaken to examine the sequential development of these forms during a 36-day period. Particularly noted were the early cell wall deficient forms observed at 36 h which appear as "cartwheels." Evolution of these forms through the various stages of the granular-appearing colonies to the classical "fried egg" morphology is described. A similar developmental pattern was observed with both a prototype of the test organism as well as with a fresh isolate from the genitourinary tract of a patient.Colonies of induced wall-defective variants of S. faecalis grown on an induction medium were examined in the electron microscope by use of the technique of ultrathin sectioning. This study was undertaken to examine, at the cellular level, the colonial morphology of these variants and to describe differences existing in specified areas of the colony. Longitudinal thin sections of the induced wall-defective colonies were prepared from three levels of the colonies as they related to the medium surface: supraagar surface; subagar surface; and deep subagar. Examination of the thin sections offers evidence that the bacterial population in a single colony is morphologically heterogeneous.

CAERULOMYCIN, A NEW ANTIBIOTIC FROM STREPTOMYCES CAERULEUS BALDACCI: I. PRODUCTION, ISOLATION, ASSAY, AND BIOLOGICAL PROPERTIES

Streplomyces caeruleus has been shown to produce a hitherto unknown antibiotic to which the name caerulomycin has been given. This was first obtained from a fresh isolate (PRL 1687), and subsequently, after the strain had been identified, from an authentic culture of S. caeruleus. It was extracted from culture filtrates with ether and purified as a colorless crystalline amphoteric substance, C12H11O2N3, which inhibited the growth of some filamentous fungi and yeasts and had weak activity against certain bacteria.