Bacteria that are highly virulent, expressing high infectivity, and able to survive nebulization, pose great risk to the human population. One of these is Francisella tularensis, the etiological agent of tularemia. F. tularensis is a subject of intense scientific interest due to the fact that vaccines for its immunoprophylaxis in humans are not yet routinely available. One of the substantial obstacles in developing such vaccines is our insufficient knowledge of processes that initiate and regulate the expression of effective protective immunity against intracellular bacteria. Here, we present data documenting the different pattern of cellular behavior occurring in an environment unaffected by microbiota using the model of germ-free mice mono-associated with F. tularensis subsp. holarctica strain LVS in comparison with a classic specific-pathogen-free murine model during early stages of infection.
- Keywords
- Cellular response, Francisella tularensis, Germ-free, Gnotobiont, Innate immunity,
- MeSH
- Bacterial Vaccines immunology MeSH
- Cytokines metabolism MeSH
- Francisella tularensis immunology pathogenicity MeSH
- Germ-Free Life immunology MeSH
- Host-Pathogen Interactions immunology MeSH
- Microbiota MeSH
- Disease Models, Animal MeSH
- Mice, Inbred BALB C MeSH
- Mice MeSH
- Specific Pathogen-Free Organisms immunology MeSH
- Peritoneum microbiology pathology MeSH
- Immunity, Innate MeSH
- Spleen microbiology pathology MeSH
- Tularemia immunology microbiology pathology MeSH
- Animals MeSH
- Check Tag
- Mice MeSH
- Female MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Names of Substances
- Bacterial Vaccines MeSH
- Cytokines MeSH
Bacteriophages are abundant components of vertebrate gut microbial communities, impacting bacteriome dynamics, evolution, and directly interacting with the superhost. However, knowledge about gut phageomes and their interaction with bacteriomes in vertebrates under natural conditions is limited to humans and non-human primates. Widely used specific-pathogen-free (SPF) mouse models of host-microbiota interactions have altered gut bacteriomes compared to wild mice, and data on phageomes from wild or other non-SPF mice are lacking. We demonstrate divergent gut phageomes and bacteriomes in wild and captive non-SPF mice, with wild mice phageomes exhibiting higher alpha-diversity and interindividual variability. In both groups, phageome and bacteriome structuring mirrored each other, correlating at the individual level. Re-analysis of previous data from phageomes of SPF mice revealed their enrichment in Suoliviridae crAss-like phages compared to our non-SPF mice. Disrupted bacteriomes in mouse models can be treated by transplanting healthy phageomes, but the effects of phageome transplants on healthy adult gut microbiota are still unknown. We show that experimental transplantation of phageomes from wild to captive mice did not cause major shifts in recipient phageomes. However, the convergence of recipient-to-donor phageomes confirmed that wild phages can integrate into recipient communities. The differences in the subset of integrated phages between the two recipient mouse strains illustrate the context-dependent effects of phage transplantation. The transplantation did not impact recipient gut bacteriomes. This resilience of healthy adult gut microbiomes to the intervention has implications for phage allotransplantation safety.
- Keywords
- bacteriome, bacteriophages, captivity, gut microbiome, house mouse, phageome, phageome transplantation, specific-pathogen-free, wild,
- MeSH
- Bacteria classification virology genetics isolation & purification MeSH
- Bacteriophages * isolation & purification genetics physiology MeSH
- Animals, Wild microbiology MeSH
- Feces microbiology virology MeSH
- Mice MeSH
- Specific Pathogen-Free Organisms MeSH
- Gastrointestinal Microbiome * MeSH
- Virome MeSH
- Animals MeSH
- Check Tag
- Mice MeSH
- Female MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
Endogenous development of a pure strain of Eimeria media and of a precocious line derived from this strain was studied in specific pathogen-free (SPF) rabbits. Endogenous development of the parental strain comprised three generations and the gamogony began 76 h post-inoculation (pi). Two types of meronts were observed in each generation. The type A meronts gave rise to large, polynucleated merozoites present in low numbers. Multiplication was carried out by endomerogony. Within type B meronts, merozoites arose from ectomerogony. These were slender and more numerous than those of type A. The sporozoite refractile body was divided and distributed into the first and second generation merozoites but not into the third. The endogenous development of the precocious line was similar to that of the parental strain except that no refractile body was observed and the last merogony was absent. Gamogony appeared 60 h pi.
- MeSH
- Species Specificity MeSH
- Duodenum parasitology ultrastructure MeSH
- Eimeria genetics growth & development ultrastructure MeSH
- Microscopy, Electron MeSH
- Ileum parasitology ultrastructure MeSH
- Jejunum parasitology ultrastructure MeSH
- Coccidiosis physiopathology MeSH
- Rabbits MeSH
- Specific Pathogen-Free Organisms MeSH
- Intestine, Small parasitology MeSH
- Animals MeSH
- Check Tag
- Rabbits MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Comparative Study MeSH
The effects of infections of Trichinella spiralis on 10 specific-pathogen-free Beagles were examined. Eight puppies received either 100, 500, 1,000, or 5,000 larvae, and 2 adult dogs received 1,000 larvae. Blood was drawn every 4 days, beginning 5 days before infection, for the determination of relative eosinophil numbers. Creatine kinase levels were monitored before infection, two weeks after infection, and one month after infection. The dogs were euthanized 1 month postinfection, and larvae were counted in muscle digests of 10 gram samples of diaphragm, pectoralis superficialis, masseter, biceps brachii, and vastus lateralis. The dogs displayed minor signs of gastrointestinal upset during the first week after infection. The dogs also developed a slight eosinophilia with a magnitude that was dependent on the number of larvae the dog received. All infected dogs, but one that had received 500 larvae, had a positive reaction with larval excretory-secretory products of T. spiralis; adult dogs had the greatest immunologic response. The creatine kinase levels were found not to be related to either the time postinfection or the magnitude of the larval dose. The number of larvae recovered from the muscles (maximum of 70 per gram) was dependent on the dosage of larvae received, but there was no significant predilection of the larvae for any of the five examined muscle groups.
- MeSH
- Feces parasitology MeSH
- Dog Diseases immunology parasitology MeSH
- Specific Pathogen-Free Organisms MeSH
- Antibodies, Helminth blood MeSH
- Dogs MeSH
- Muscles parasitology MeSH
- Trichinella immunology isolation & purification physiology MeSH
- Trichinellosis immunology parasitology veterinary MeSH
- Blotting, Western MeSH
- Animals MeSH
- Check Tag
- Male MeSH
- Dogs MeSH
- Female MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- Antibodies, Helminth MeSH
The endogenous cycle of Eimeria flavescens was studied in specific pathogen-free rabbits by means of histology and transmission electron microscopy. In total, five asexual generations were observed and two types of meronts and merozoites were found in each generation. Type A gave rise to a smaller number of thick polynucleate merozoites in which daughter merozoites were formed by endomerogony, while in the type B meronts slender uninucleate merozoites arose from ectomerogony. The first generation meronts were found in the crypts and proximal part of the villi of the duodenum and jejunum, whereas the three following generations developed in the superficial epithelium of the large intestine (cecum, vermiform appendix and colon). The last merogony as well as gamogony took place in crypts of the large intestine.
- MeSH
- Eimeria growth & development pathogenicity ultrastructure MeSH
- Microscopy, Electron MeSH
- Coccidiosis parasitology pathology MeSH
- Rabbits parasitology MeSH
- Specific Pathogen-Free Organisms MeSH
- Intestinal Diseases, Parasitic parasitology pathology MeSH
- Parasitic Diseases, Animal parasitology pathology MeSH
- Life Cycle Stages MeSH
- Intestinal Mucosa parasitology pathology MeSH
- Animals MeSH
- Check Tag
- Rabbits parasitology MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
The coccidium Eimeria exigua from the tame rabbit (Oryctolagus cuniculus) has been neglected so far since it was considered to be an invalid species. Indeed, little is known about this coccidium. We have studied its endogenous development in domestic rabbits by means of light and electron microscopy. The first meronts appeared 72h post-inoculation (h.p.i.), but a total of four asexual generations developed from 72 to 144h.p.i. Meronts and gamonts were localized in the small intestine and the asexual stages successively moved from the duodenum to ileum. All parasite stages were found exclusively in the epithelium of the walls and tops of the villi. Two types of meronts developing in parallel during the asexual phase were observed from at least the 2nd generation. As in other rabbit coccidia, these forms corresponded to type A, which usually develops two polynucleate merozoites where endomerogony occurs, and type B, characterized by more numerous uninucleate merozoites arising by ectomerogony. This report is the first description of the endogenous stages of E. exigua.
Specific pathogen-free (SPF) rabbits were inoculated with oocysts of an original strain (OS) of Eimeria piriformis and the first newly developed oocysts recovered from the intestine were used for infection of other rabbits. The prepatent period (PP) was shortened after 12 passages from 194 to 170 hours and remained stable after 5 passages without any selection pressure. Oocysts of the precocious line (PL) exhibited peculiar morphology. Besides refractile bodies (RB) within sporozoites, one huge RB joined with a residual body was present inside each sporocyst. The parasite developed in the proximal colon and, to a lesser extent, in other parts of the large intestine. All stages were seen in the epithelium of crypts. In OS, four asexual generations preceded gamogony and, like in other rabbit coccidia, two types of meronts were observed: meronts of type A that develop into polynucleate merozoite, in which endomerogony takes place, and meronts of the type B that form uninucleate merozoites. The endogenous development of PL was identical with that of OS except for the last merogony which was absent. This resulted in earlier appearance of gamogony and shortening of PP. These observations of the life cycle of E. piriformis substantially improve on its description made 50-60 years ago.
- MeSH
- Eimeria growth & development pathogenicity physiology MeSH
- Coccidiosis parasitology pathology veterinary MeSH
- Rabbits MeSH
- Oocysts growth & development MeSH
- Specific Pathogen-Free Organisms MeSH
- Intestinal Diseases, Parasitic parasitology pathology veterinary MeSH
- Sporozoites growth & development MeSH
- Life Cycle Stages * MeSH
- Intestinal Mucosa parasitology pathology MeSH
- Intestine, Small parasitology pathology MeSH
- Animals MeSH
- Check Tag
- Rabbits MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Naive and immune specific-pathogen-free rabbits were inoculated in the duodenum with sporocysts of Eimeria coecicola or Eimeria intestinalis. Samples were taken from the following tissues: duodenum (site of penetration of sporozoites), ileum (specific target site of the endogenous development of E. intestinalis), vermiform appendix (target site of E. coecicola) and two extraintestinal sites, mesenteric lymph nodes (MLNs), and spleen. The presence of sporozoites was checked by immunohistochemistry. In rabbits primary-infected with E. coecicola, large numbers of sporozoites were detected in the duodenum, extraintestinal sites, and vermiform appendix. The abundance of sporozoites in the spleen, MLN, and appendix was significantly reduced in the immune rabbits, and the migration seemed impeded. In the rabbits infected with E. intestinalis, sporozoites were absent in the spleen and MLN, indicating that the route of migration is different from that of E. coecicola. The number of sporozoites in the crypts of the ileum was markedly reduced in the immune animals.
- MeSH
- Antigens, Protozoan metabolism MeSH
- Eimeria growth & development immunology pathogenicity MeSH
- Host-Parasite Interactions MeSH
- Coccidiosis immunology parasitology MeSH
- Rabbits MeSH
- Lymph Nodes parasitology MeSH
- Specific Pathogen-Free Organisms MeSH
- Intestinal Diseases, Parasitic * MeSH
- Peyer's Patches metabolism parasitology MeSH
- Antibodies, Protozoan immunology MeSH
- Spleen parasitology MeSH
- Sporozoites growth & development immunology pathology MeSH
- Intestine, Small metabolism parasitology pathology MeSH
- Animals MeSH
- Check Tag
- Rabbits MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- Antigens, Protozoan MeSH
- Antibodies, Protozoan MeSH
Mus musculus is the classic mammalian model for biomedical research. Despite global efforts to standardize breeding and experimental procedures, the undefined composition and interindividual diversity of the microbiota of laboratory mice remains a limitation. In an attempt to standardize the gut microbiome in preclinical mouse studies, here we report the development of a simplified mouse microbiota composed of 15 strains from 7 of the 20 most prevalent bacterial families representative of the fecal microbiota of C57BL/6J Specific (and Opportunistic) Pathogen-Free (SPF/SOPF) animals and the derivation of a standardized gnotobiotic mouse model called GM15. GM15 recapitulates extensively the functionalities found in the C57BL/6J SOPF microbiota metagenome, and GM15 animals are phenotypically similar to SOPF or SPF animals in two different facilities. They are also less sensitive to the deleterious effects of post-weaning malnutrition. In this work, we show that the GM15 model provides increased reproducibility and robustness of preclinical studies by limiting the confounding effect of fluctuation in microbiota composition, and offers opportunities for research focused on how the microbiota shapes host physiology in health and disease.
- MeSH
- Bacteria classification genetics MeSH
- Species Specificity MeSH
- Feces microbiology MeSH
- Phenotype MeSH
- Germ-Free Life * MeSH
- Metagenomics methods MeSH
- Mice, Inbred C57BL MeSH
- Mice MeSH
- Specific Pathogen-Free Organisms * MeSH
- Whole Genome Sequencing methods MeSH
- Gastrointestinal Microbiome genetics physiology MeSH
- Body Weight genetics physiology MeSH
- Animals MeSH
- Check Tag
- Male MeSH
- Mice MeSH
- Female MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Research Support, N.I.H., Extramural MeSH
Substances which have the same properties as the previously described lymph node activating factor are released from the 4-h culture of 10 X 10(6) lymph node cells from normal non-sensitized mice and 2.5--5 X 10(6) Mycobacterium kansasii cells. They increase the number of lymphocytes with nucleoli synthesizing ribonucleic acid in the popliteal lymph nodes of intact mice and give the precipitation lines with the beta- to alpha-globulin electrophoretic mobility, which are specific for the lymph node activating factor, in reaction with serum against the supernatants from mixed lymphocyte cultures. The conclusion drawn from these observations is that the release of the factor or related substances is one of the more general manifestations of the early response of lymphocytes to foreign cells. The activating and in immunoelectrophoresis specifically reacting substance is not released from lymphocytes of mice from a specific pathogen-free colony. We assume that the release of the factor is not the primary reaction of the non-sensitized lymphocytes but the secondary reaction of lymphocytes presensitized with substances which share antigenic determinants with Mycobacteria.
- MeSH
- Lymphocyte Activation * MeSH
- Immunoelectrophoresis MeSH
- Cells, Cultured MeSH
- Lymphocytes metabolism MeSH
- Mycobacterium * MeSH
- Mice, Inbred BALB C MeSH
- Mice, Inbred C57BL MeSH
- Mice MeSH
- Specific Pathogen-Free Organisms MeSH
- RNA biosynthesis MeSH
- Animals MeSH
- Check Tag
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Names of Substances
- RNA MeSH
