Ultracytochemistry of phosphohydrolase of the microorganisms and phagocytes in gonococcal infection

The complex study of phosphohydrolases (Mg2+ATPase, Na+,K+ATPase) and adenylate cyclase in gonococci, both in vivo and in vitro, and in phagocytes in gonococcal infection has been carried out with the use of ultracytochemical techniques. The enzymatic activity in the cellular structures of micro- and macroorganisms under study has been visualized. The prospects of the ultracytochemical approach to the study of the enzymes of nucleotide metabolism, their role in the life of eu- and prokaryotes, as well as the ways for affecting the enzymatic systems of cells are discussed.     

Structural variations in pili expressed during gonococcal infection

Gonococci were cultured from the urethra of male patients and from the cervix and urethra of their female partners. SDS-PAGE of cell lysates from within each group of consorts showed that outer membrane protein I remained constant but considerable variations were seen in the apparent molecular weight of protein II. Pili were purified from the isolates of some groups of consorts. In each case the pili expressed by the isolates from the female cervix and urethra differed in subunit molecular weight and were usually also distinct from the pili expressed by the isolate from the male partner.     

Establishment of a human CEACAM1 transgenic mouse model for the study of gonococcal infections

Neisseria gonorrhoeae is the causative microorganism for the sexually transmitted disease (STD) gonorrhea and humans are its only natural host. An animal model would be a useful tool for gonorrhea research, therefore we developed the hCEACAM1 transgenic mice, using an eukaryotic expression vector, pCDPCAM1-GI. This construct was microinjected into the zygotes of C57BL/6 mice and 22 F0 generation transgenic mice were obtained. Four (lines 50, 53, 54, and 59) of the F0 generation were found to carry the transgene by PCR and sequence analysis, respectively. Western blotting and Fluorescence-Activated Cell Sorting Analysis demonstrated that hCEACAM1 was expressed on the cell membrane of various tissues in the line 53 transgenic mouse. To initiate the disease in the animal model, the F2 or F3 transgenic mice were inoculated with N. gonorrhoeae intravaginally. Compared with normal mice, N. gonorrhoeae can successfully infect and cause inflammation in the transgenic mice. These data suggested the feasibility of using hCEACAM1 transgenic mice as an animal model for gonococcal infections.     

Establishment of a human CEACAM1 transgenic mouse model for the study of gonococcal infections

Neisseria gonorrhoeae is the causative microorganism for the sexually transmitted disease (STD) gonorrhea and humans are its only natural host. An animal model would be a useful tool for gonorrhea research, therefore we developed the hCEACAM1 transgenic mice, using an eukaryotic expression vector, pCDPCAM1-GI. This construct was microinjected into the zygotes of C57BL/6 mice and 22 F0 generation transgenic mice were obtained. Four (lines 50, 53, 54, and 59) of the F0 generation were found to carry the transgene by PCR and sequence analysis, respectively. Western blotting and Fluorescence-Activated Cell Sorting Analysis demonstrated that hCEACAM1 was expressed on the cell membrane of various tissues in the line 53 transgenic mouse. To initiate the disease in the animal model, the F2 or F3 transgenic mice were inoculated with N. gonorrhoeae intravaginally. Compared with normal mice, N. gonorrhoeae can successfully infect and cause inflammation in the transgenic mice. These data suggested the feasibility of using hCEACAM1 transgenic mice as an animal model for gonococcal infections.     

Beauveria bassiana infection of eggs of stored-product beetles

Beauveria bassiana (Balsamo) Vuillemin was tested under maximum challenge conditions with an estimated dose of 1.1 × 10⁵ conidia/mm² for its effects on eggs of four of the major beetle pests of stored grain and grain products. When ambient relative humidity (RH) was 92%, hatch of fungus-treated Rhyzopertha dominica (Fabricius) eggs was 13% versus 58% for control eggs, and hatch of treated Tribolium castaneum (Herbst) was 17% versus 51% for controls. There was no fungus effect at RH of 48 and 73%. Fungus treatment of Cryptolestes ferrugineus (Stephens) and Oryzaephilus surinamensis (Linnaeus) eggs had no effect. Sectioned T. castaneum eggs demonstrated that the fungus penetrates and infects them.     

Pathogenesis of anAspergillus flavus infection ofGalleria mellonella eggs

Egg masses of the greater wax moth,Galleria mellonella L. experimentally infected with conidia ofAspergillus flavus Link became rapidly covered with the mycelium and were eventually destroyed. Germ tubes from conidia penetrated not only infertile, but also damaged eggs. Healthy eggs were often penetrated both by conidial germ tubes and mycelia elements. Once penetrated, eggs become filled with mycelium in as little as two days, after which conidiophores and mycelia protrude outwardly through the chorion.

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Résumé Des pontes de la Teigne des ruches,Galleria mellonella, infectées expérimentalement avec des conidies deAspergillus flavus ont été rapidement recouvertes de mycélium et furent éventuellement détruites. Les tubes germinatifs issus des conidies ont pénétré non seulement les œufs infertiles mais aussi les œufs blessés. Les œufs sains furent souvent pénétrés à la fois par des tubes germinatifs conidiens et des éléments mycéliens. Une fois pénétrés, les œufs se remplissent de mycélium en moins de 2 jours, après lesquels le mycélium et les conidiophores ressortent à l'extérieur à travers le chorion.

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Authorized for publication on November 7, 1968 as paper No. 3503 in the Journal Series of the Pennsylvania Agricultural Experiment Station.     

The transferrin receptor expressed by gonococcal strain FA1090 is required for the experimental infection of human male volunteers

Iron, an essential nutrient for most microorganisms, is sequestered by the host to decrease the concentration of iron available to bacterial pathogens. Neisseria gonorrhoeae , the causative agent of gonorrhoea, can acquire iron by direct interaction with human iron-binding proteins, including the serum glycoprotein, transferrin. Iron internalization from host transferrin requires the expression of a bacterial receptor, which specifically recognizes the human form of transferrin. Two gonococcal transferrin-binding proteins have been implicated in transferrin receptor function, TbpA and TbpB. We constructed a gonococcal transferrin receptor mutant without the introduction of additional antibiotic resistance markers and tested its ability to cause experimental urethritis in human male volunteers. The transferrin receptor mutant was incapable of initiating urethritis, although the same inoculum size of the wild-type parent strain, FA1090, causes urethritis in >90% of inoculated volunteers. To our knowledge, this is the first experimental demonstration that a bacterial iron acquisition system is an essential virulence factor for human infection.     

Response surfaces for overdispersion in the study of the conditions for fish eggs hatching

Response surface methodology, originally developed for determining optimal conditions in industrial experiments, was early adapted to experiments in marine ecology. However, these involved studying the shape of the complete response surface, not only detecting the optimum, and often had counts or durations as the response variable. Thus, nonlinear, nonnormal response models were required. For counts, binomial and beta-binomial models have been used, the latter because of substantial overdispersion. In closely controlled experiments, overdispersion among units held under the same conditions might indicate that some mishap has occurred in conducting the study. One possible check is to model the dispersion as a second response surface. This procedure is used to show that overdispersion in fish egg hatching experiments has a biological explanation in that it occurs only under suboptimal hatching conditions.