The present invention relates to a method of preparing a live attenuated vaccine by irradiation and a live attenuated vaccine composition prepared by the same, and more particularly, a method of preparing a live attenuated vaccine by irradiation including irradiating a pathogenic microorganism with a dose of 0.5 to 2 kGy of radiation per single radiation six to fifteen times; and a live attenuated vaccine composition including a pathogenic microorganism attenuated to not be revertant to a wild type by generation of at least one mutation of nucleotide insertion and nucleotide deletion by irradiation.

The purpose of the present invention is to provide a detection means whereby Staphylococcus aureus can be identified at a high accuracy. An aspect of the present invention relates to a medium for detecting S. aureus which comprises one or more kinds of nutrient components, a color developing agent capable of developing a color in the presence of α-glucosidase, a color developing agent capable of developing a color in the presence of phosphatase and 0.5 mg/cm.sup.3 or more of sodium colistin methanesulfonate. Another aspect of the present invention relates to a sheet for detecting S. aureus, said sheet comprising the aforesaid medium, and a method for detecting S. aureus with the use of the medium and sheet as described above.

Covalently cross-linked pilus polymers displayed on the cell surface of Gram-positive bacteria are assembled by class C sortase enzymes. These pilus-specific transpeptidases located on the bacterial membrane catalyze a two-step protein ligation reaction—first, cleaving the LPXTG motif of one pilin protomer to form an acyl-enzyme intermediate, and second, joining the terminal threonine to the nucleophilic lysine residue residing within the pilin motif of another pilin protomer. Informed by the high-resolution crystal structures of corynebacterial pilus-specific sortase (SrtA) and by developing structural variants of the sortase enzyme whose catalytic pocket has been unmasked by activating mutations, we have developed new reagents capable of forming isopeptide bonds in vitro. The reagents disclosed herein can catalyze ligation of isolated SpaA domains in vitro provide a facile and versatile new platform for protein engineering and bio-conjugation that has major implications for biotechnology.

The present disclosure discloses a methicillin-resistant staphylococcus aureus mutant strain and use thereof, and belongs to the field of molecular biology and microorganisms. The methicillin-resistant staphylococcus aureus mutant strain disclosed by the present disclosure has a relatively low exopolysaccharide synthesis ability and a relatively low biofilm metabolism ability, but it is sensitive to an antibiotic cefoxitin. The mutant strain can be used for treating a related disease caused by methicillin-resistant staphylococcus aureus infection through an endogenous ecological treatment strategy. The present disclosure provides a new idea for treating the disease.

Methods to edit genes by administering a chimeric nuclease to a cell or organism without the use of a viral vector.

The invention provides in part methods of treating cancers of a specific organ or tissue by administering a composition that is antigenically specific for one or more microbes that are pathogenic in the specific organ or tissue in which the cancer is situated.

Cell populations, compositions, and methods are provided relating to target priming of macrophage cells. The macrophages, once primed or activated with a microorganism, can be used to prevent or treat infection by the microorganism. Likewise, once primed or activated by a tumor cell or tumor antigen, the macrophage cell can be used to prevent or treat tumor of the same kind. The priming can be carried out in vitro or ex vivo. The macrophages can be isolated from the subject of disease prevention or treatment.

Binding agents able to disrupt bacterial biofilms of diverse origin are described, including monoclonal antibodies secreted by human B lymphocytes. Methods to prevent formation of or to dissolve biofilms with these binding agents are also described. Immunogens for eliciting antibodies to disrupt biofilms are also described.

The present invention refers to a method for the production of live attenuated bacterial strains, suitable as vaccine candidates, comprising the steps of: A. providing a bacterial strain capable of expressing glutamate racemase and possibly D-amino acid transaminase and comprising a peptidoglycan cell wall, and B. inactivating the gene or genes encoding for the glutamate racemase enzyme and, if needed, the gene or genes encoding for the enzyme D-amino acid transaminase in such way that the bacterial strain is no longer capable of expressing a functional glutamate racemase and/or a functional D-amino acid transaminase;
wherein the inactivation of said genes causes said bacterial strain to be auxotrophic for D-glutamate.

The present invention relates to a method of preparing a live attenuated vaccine by irradiation and a live attenuated vaccine composition prepared by the same, and more particularly, a method of preparing a live attenuated vaccine by irradiation including irradiating a pathogenic microorganism with a dose of 0.5 to 2 kGy of radiation per single radiation six to fifteen times; and a live attenuated vaccine composition including a pathogenic microorganism attenuated to not be revertant to a wild type by generation of at least one mutation of nucleotide insertion and nucleotide deletion by irradiation.