摘要:

A system is described for culturing an obligate photoautotroph,Plectonema boryanum, on glucose in the dark. This consisted of a continuous flow-through apparatus, by means of which fresh sterile media was continually replenished. Algal cells grown in the dark on glucose are deficient in chlorophyll, but regained their chlorophyll after exposure to light and are able to grow in their usual mineral salts medium, when transferred to the light.

ISSN:0008-4166    

DOI:10.1139/m72-043

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Bdellovibrio bacteriovorusstrain 6-5-S, grown on autoclaved cells ofSpirillum serpens, strain VHL, released a lytic enzyme into the culture fluid. This lytic principle degraded heat-killed but not viable cells ofS.serpensVHL. Cell envelopes and purified peptidoglycan fromS.serpenswere also broken down by the same lytic enzyme produced byB.bacteriovorusand it also degraded heat-killed cells and cell envelopes of the parasite.

ISSN:0008-4166    

DOI:10.1139/m72-044

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Exogenous carbon and nitrogen sources were necessary for complete swelling (spherical growth) and germ-tube formation fromAspergillus nigerspores. The rate of spherical growth was low at 30°, maximum at 38°, and decreased at higher temperatures until at 47° inhibition was complete. At temperatures from 35° to 44° the final spore size was similar and greater than at 30° although the time taken to reach this size varied. Germ-tube formation occurred in from 97 to 99% of the spores with a good degree of synchrony between 30° and 38°. At temperatures from 38° to 43° the proportion of spores which produced germ tubes gradually decreased with a concurrent loss of synchrony. At 44° germ-tube formation was completely inhibited although spherical growth could occur over a prolonged period to produce large spherical cells. This increase of cell volume was apparently accompanied by a system of wall extension which involved wall synthesis. Under conditions of spore crowding an inhibition became apparent which affected only the initiation of spherical growth and not the spherical-growth process itself. Other effects of spore crowding were observed and were attributed to alterations in the gaseous environment. Increased spherical growth was always accompanied by a greater degree of branching of the germ tube when produced and a hypothesis relating these effects is suggested.

ISSN:0008-4166    

DOI:10.1139/m72-045

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Sixty-five batches of three types of monkey kidney cells were examined by light and electron microscopy for the presence of simian viruses. Cynomolgus cells showed the highest contamination rate (67%), followed by rhesus (18%). Foamy virus was the most common contaminant, being detected in 13 batches, twice in concert with a paramyxovirus. Six batches contained a paramyxovirus; one batch contained a papovavirus. Of the 22 batches of African green monkey kidney cells examined, none showed evidence of virus. "Healthy" established cell lines from three laboratories were also checked by electron microscopy, and several contaminating viruses were found. These were apparently either accidentally introduced during handling, as in the case of SV5, reovirus, and parvovirus, or were latent viruses (hamster and mouse) derived from the host tissue. While negative staining provided the simplest technique for detection of the viral contaminants, thin sectioning was required to locate foamy virus and the latent "tumor" viruses. A rapid method for the preparation of thin sections is described.

ISSN:0008-4166    

DOI:10.1139/m72-046

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Immunochemical properties of a parental strain ofC.albicansand of four transformants, obtained by exposing competentC.albicanscells to deoxyribonucleic acid (DNA) ofMycobacterium tuberculosis, were examined by selected methods. It was found that the cytoplasms of all the Candidas shared at least one antigen, but the transformants alone contained two additional antigenic factors. The cytoplasm preparations of all the Candidas were found immunologically related toM.microti,M.kansasii,M.abscessus, and to some strains of Runyon's Group IV, as well as to many Nocardias, Streptomycetes, Actinomycetes, Mycococci, and Dermatophili. The transformants were also related to the non-chromogenic mycobacteria.

ISSN:0008-4166    

DOI:10.1139/m72-047

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Slide cultures showed that growth of a hydrocarbon-utilizingTorulopsissp. occurred only when the cells were in physical contact with then-alkane droplets. Growth in batch culture was found to be linear and dependent on the surface area of substrate available to the cells. The hydrocarbon may enter the cell without first being converted to a more water-soluble intermediate.

ISSN:0008-4166    

DOI:10.1139/m72-048

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Studies on the oxygen requirements of aerobic psychrotolerant bacteria showed that the oxygen concentration of the atmosphere can be lowered to 2% without noticeably inhibiting growth rate. Tests were made with meat-spoilage strains ofAchromobacterandPseudomonasin nutrient media sparged with gases containing from 0.1 to 100% oxygen. Reduction of overall growth rate with reduction in oxygen concentration below 2% was mainly the result of an increase in the lag period. At an oxygen concentration of 0.5% or lower, however, cell generation time during the logarithmic phase was increased and cell yield at the stationary phase was reduced. The increased lag period could be eliminated by using an inoculum adapted to the oxygen concentration under test. Growth did not occur in the absence of oxygen. Oxygen concentrations greater than 21% (air) had a negligible effect onPseudomonas, but inhibited the growth rate ofAchromobacter. The results indicate that insufficient oxygen is not a major cause of the failure of these bacteria to grow rapidly in vacuum packaged meats.

ISSN:0008-4166    

DOI:10.1139/m72-049

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Broken cell preparations of the blue-green algaGloeocapsasp. LB 795 reduce acetylene to ethylene and evolve hydrogen in the presence of sodium dithionite and adenosine triphosphate (ATP). The enzyme system is almost completely inhibited by adenosine diphosphate (ADP) (7.5 mM), O2and CO (0.01 atm), and CO2(0.05 atm). Its kinetic properties are very similar to those of nitrogenases from other sources, but, unlike the enzymes so far isolated from other blue-green algae,Gloeocapsanitrogenase is sedimented by centrifugation at 10 000 g.

ISSN:0008-4166    

DOI:10.1139/m72-050

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

A study was made to determine whether herpes simplex virus (HSV)-infected HEp-2 cell nuclei, when isolated post infection (p.i.) and incubated in the absence of cytoplasm, were capable of maintaining synthesis of protein and deoxyribonucleic acid (DNA). Demonstration of synthesis in nuclei isolated post infection was measured by the incorporation of14C-glutamate into protein or3H-thymidine into DNA. Both uninfected and HSV-infected nuclei synthesized nuclear protein and DNA for 2 h post isolation (p.e.). Similar rates of in vitro synthesis of nuclear protein were found in uninfected nuclei and nuclei isolated 2 h or 4 h post infection. In vitro synthesis of DNA occurs at about one-fourth the rate in virus-infected nuclei as compared to uninfected nuclei. These data serve as a determination of nucleus viability preceding further studies involving the maturation of HSV in isolated nuclei when incubated free from cytoplasmic control.

ISSN:0008-4166    

DOI:10.1139/m72-051

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Specific immunofluorescence demonstrated a unique intranuclear fluorescent mass in incubated isolated herpes simplex virus (HSV)-infected HEp-2 nuclei. The intranuclear mass was observed to undergo a change in form, or maturation, during in vitro incubation when nuclei were isolated from HEp-2 cells 7 h post infection (p.i.). Both the accumulation and maturation of the intranuclear antigenic mass did not occur in HSV-infected nuclei isolated from HEp-2 cells grown in arginine-deficient medium. An accumulation of DNase-resistant acridine orange stainable aggregates occurred during in vitro incubation of nuclei isolated from 7- or 9-h HSV-infected cells. Enhanced nucleopathic effects did not occur under the same conditions of in vitro incubation. These data suggest that nuclei isolated from HSV-infected HEp-2 cells several hours p.i. are capable of allowing intranuclear virus development to continue under in vitro conditions in the absence of cytoplasmic contact. The findings may help to elucidate some of the roles of the cytoplasm and nucleus in herpes-virus development.

ISSN:0008-4166    

DOI:10.1139/m72-052

出版商:NRC Research Press    

年代:1972

数据来源: NRC