Sequence and properties of mecA, a negative regulator of genetic competence in Bacillus subtilis

The development of competence in Bacillus subtilis is regulated by growth conditions and several regulatory genes. In complex media competence development is poor, and there is little or no expression of late competence genes. mec mutations permit competence development and late competence gene expression in complex media, and bypass the requirements for many of the competence regulatory genes. In this paper we describe the cloning and characterization of mecA. The mecA gene product acts negatively in the development of competence. Null mutations in mecA allowed expression of a late competence gene comG, under conditions where it is not normally expressed, including in complex media and in cells mutant for several competence regulatory genes. Overexpression of MecA from a multicopy plasmid resulted in inhibition of comG transcription. The DNA sequence of mecA was determined and the predicted gene product showed no significant similarity to any protein in the database. Expression of a mecA-lacZ translational fusion was constitutive during growth and did not vary significantly in the different media tested. The role of mecA in competence development and other stationary phase phenomena is discussed.

Recurrent erythema migrans despite extended antibiotic treatment with minocycline in a patient with persisting Borrelia burgdorferi infection

Erythema migrans recurred in a patient 6 months after a course of treatment with minocycline for Lyme disease. Polymerase chain reaction on heparinized peripheral blood at that time demonstrated the presence of Borrelia burgdorferi-specific DNA. The patient was seronegative by Lyme enzyme-linked immunosorbent assay but showed suspicious bands on Western blot. Findings of a Warthin-Starry stain of a skin biopsy specimen of the eruption revealed a Borrelia-compatible structure. Reinfection was not believed to have occurred. Further treatment with minocycline led to resolution of the erythema migrans.

A novel inositol mono-phosphatase inhibitor from Memnoniella echinata. Producing organism, fermentation, isolation, physicochemical and in vitro biological properties

A novel inositol mono-phosphatase inhibitor, L-671,776 (1), was discovered from a culture of the hyphomycete, Memnoniella echinata (ATCC 20928). 1 has a molecular weight of 388 and a molecular formula of C23H32O5. The mode of inhibition is non-competitive, with a Ki of 450 microM. It shows no inhibition of myo-inositol 1,4-bisphosphate 1-phosphatase or myo-inositol 1,4,5-triphosphate 5-phosphatase, although it weakly inhibits myo-inositol 1,4,5-triphosphate 3-kinase (IC50 = 3 mM). It elevates inositol monophosphates in rat parotid slices (EC50 approximately 3 mM), but abolishes agonist effects. It also produces short-lived contraction of guinea pig trachea at 300 microM.

[Pharmacological studies on erzhi pills]

The experimental results show that Erzhi Pills can markedly increase the weights of immunological organs in mice and antagonize the immunosuppressive action of prednisolone. The diameter of SRID precipitating ring, the hemolytic ability of PFC and the clearance rate of i.v. charcoal particles in mice can all be increased by the pills. Erzhi Pills also protect mice from CCl4 intoxication. Steamed Ligustrum lucidum has the same action as Erzhi Pills.

Evidence for a new Escherichia coli protein resembling a lysyl-tRNA synthetase

The amino acid sequence deduced from the nucleotide sequence of an open reading frame adjacent to the frdA gene of Escherichia coli shows 30.5% identity with the C terminus of Escherichia coli lysyl-tRNA synthetases. The three motifs characteristic of aminoacyl-tRNA synthetases of class 2 are recognizable within this sequence.