Acta microbiologica Academiae Scientiarum Hungaricae最新文献

Germfree and conventional mice responded similarly to pertussis vaccine treatment. In both groups, lymphocytosis and splenomegaly developed in a similar proportion. The formalin stress reaction of germfree and conventional mice with hypertrophic lymphoid organs induced by pertussis vaccine differed from that of untreated mice: the treated germfree and conventional mice showed a acute increase of lymphocytosis without an significant change in splenomegaly.

Abortive human cytomegalovirus (HCMV) infection of normal hamster cells is accompanied by formation of cytoplasmic and surface receptors for the Fc portion of nonimmune IgG molecules. The process requires RNA and protein synthesis but no DNA synthesis. The surface receptors are detectable only transiently, in a small proportion of the cells. The receptors are also present in cells transformed by HCMV in vitro (87-TRH-5 and CX-90-3B cell lines) as well as in cells of lines TSC-1 and TSC-2 from tumours induced by these cells. Consequently, the indirect immunofluorescence test performed with sera containing no HCMV antibodies may give a positive reaction in the cytoplasm and/or cell membrane of the transformed cells.

Protoplasts obtained by snail enzyme treatment from two stable auxotrophic mutants of the yeast Candida utilis were induced to fuse by the use of polyethylene glycol. The hybrids formed from the auxotrophic parental strains were selected by complementation on stabilized minimal medium. Many of the hybrids were unstable and readily dissociated into their parental strains. Others, in which parental nuclei had fused, gave stable hybrid progeny. cytological and genetic evidence of these processes is presented.

Serologically defined Proteus strains including 120 P. vulgaris, 356 P. mirabilis, 47 P. morganii, 36 P. rettgeri and 66 P. inconstans cultures isolated from a wide variety of sources, were classified by proticine (bacteriocine) typing. Using Cradock-Watson's set of indicator and producer strains, the isolates were tested for proticine production (P type) and for proticine sensitivity (S type). P. vulgaris was typable by the P method in 4.1%, by the S method in 41.6%. The respective percentages for P. mirabilis were 60.1 and 48.9. Most strains of P. morganii, P. rettgeri and P. inconstans were untypable by both methods. A correlation has been demonstrated between P/S types and certain serogroups and serotypes of P. mirabilis. It has been concluded that, in combination with the determination of O and H antigens, the P/S method of proticine typing has a high differentiating value in the epidemiological tracing of P. vulgaris and P. mirabilis.

The effect of two concentrations of methicillin on the distribution of fatty acid (FA) in the individual phospholipids of the middle-log phase cultures of Staphylococcus aureus 5814S sensitive to methicillin was studied during a period of 2 h. In the presence of 1/2 X minimum inhibitory concentration (MIC) of methicillin (= 1 microgram/ml) the ratio of unsaturated fatty acid (UFA) + branched fatty acid (BFA) to saturated fatty acid (SFA) in the phosphatidic acid (PA) and in the C55-isoprenylphosphate (C55-IP) became significantly higher due mainly to the accumulation of n-C12 : 3, ai-C17 : 0, and ai-C19 : 0, and to the fall of n-C14 : 0, n-C16 : 0, and n-C20 : 0 in the PA, and to the 3-fold increase in n-C12 : 3 and a 2-fold decrease in the SFAs of the C55-IP. In contrast, the ratio of UFA + BFA to SFA was smaller in the phosphatidylglycerol (PG) and lysylphosphatidylglycerol (LPG) than that of the control. The reduction was attributed to a loss of ai-C15 : 0 and a gain of n-C20 : 0 in the PG, and to the decrease in ai-C17 : 0 and to the increase in n-C20 : 0 in the LPG. On the whole, the fluidity of the membrane phospholipids decreased. In the presence of 1 X MIC of methicillin (= 2 micrograms/ml) the ratio of UFA + BFA to SFA became higher in the PA due mainly to the prevention of the release of n-C18 : 1. In all the other phospholipids the ratio of UFA + BFA to SFA was smaller than in the control of the same age. The decrease in the ratios ranged in the order of C55-IP, PG, diphosphatidylglycerol (DPG) and LPG. The changes were attributed to the decrease in the proportion of n-C12 : 3 and ai-C15 : 0 or ai-C17, and to the increase in n-C20 : 0, except DPG. Thus the membranes in methicillin treated cocci were significantly less fluid than in the controls.

Commercial vaccines including bacterial as well as live and inactivated viral vaccines were examined in the rabbit pyrogen test and in the limulus test. The laboratory results were compared with the reactivity in humans. A fairly good correlation was found between the temperature rise in rabbits and the frequency of febrile reaction in the vaccinees. Two rabies vaccines and a tick-borne encephalitis virus vaccine, each pyrogenic both in rabbit and in man. were negative in the limulus test. The pyrogenicity of these vaccines is attributed to the vaccine virus itself.

Sixteen strains of Mycobacterium tuberculosis isolated in Burma were investigated for microcolonial texture using the thin section technique developed at the WHO Collaborating Centre in Prague. The strains were grown in deep (Sula's liquid medium) and surface cultures (Loevenstein-Jensen medium). Their colonies killed by 10% formol were embedded in 2% agar and paraffin, cut by a Reichert microtome and stained by the Ziehl-Neelsen technique. According to the surface texture and deep growth pattern, the Burmese strains were divided in three different groups. The European type was characterized by a growth strictly confined to the surface of the Loevenstein-Jensen medium, the African type by combined surface and subsurface growth, and the Burmese type not seen in Europe and Africa by non acid-fast granular and acid-fast colonies with distinct formation of strongly acid-fast cords both in surface and subsurface growth.

A procedure more efficient than the earlier ones was developed for the isolation of mycobacteria from heavily contaminated materials. The contaminating microbes were killed by acid decontamination preceded by an incubation of 1 g sample in 5 ml nutrient broth at 33 degrees C for 4 h. The efficiency of isolation was examined using culture media containing varying concentrations of dimetridazole and/or clotrimazole (Canesten Bayer). None of 40 mycobacterial strains representing all 4 Runyon groups was inhibited by 80 micrograms/ml of either of the inhibitors. From the sediment of acid-decontaminated samples, Löwenstein-Jensen medium containing 10 micrograms/ml of both dimetridazole and clotrimazole as well as Petragnani medium with and without glycerol and Sula media were inoculated. Model experiments and processing of 44 routine samples have made likely that aerobic sporeformers on the one hand and fungi and anaerobes on the other are killed, or at least depressed in growth, by pre-incubation combined with the addition of clotrimazole and dimetridazole to the culture medium. Thus, the isolation rate of mycobacteria can be improved.