Murine lethal toxic shock caused by intranasal administration of staphylococcal enterotoxin B.

Currently available murine staphylococcal enterotoxin B (SEB) shock models require pretreatment with various agents to increase mouse sensitivity to SEB. This study was performed to show that C3H/HeJ mice are highly susceptible to intranasal SEB inoculation, which caused toxic shock without using pretreatment agents. For this purpose, mice were injected intranasally with different doses of SEB and observed for up to 1 month.

Genetic determinants of dengue type 4 virus neurovirulence for mice.

Mouse-adapted dengue type 4 virus (DEN4) strain H241 is highly neurovirulent for mice, whereas its non-mouse-adapted parent is rarely neurovirulent. The genetic basis for the neurovirulence of the mouse-adapted mutant was studied by comparing intratypic chimeric viruses that contained the three structural protein genes from the parental virus or the neurovirulent mutant in the background sequence of nonneurovirulent DEN4 strain 814669. The chimera that contained the three structural protein genes from mouse neurovirulent DEN4 strain H241 proved to be highly neurovirulent in mice, whereas the chimera that contained the corresponding genes from its non-mouse-adapted parent was not neurovirulent.

Protonated pyrimidine-purine-purine triplex.

We have studied a protonated pyrimidine-purine-purine (Py-Pu-Pu) triplex, which is formed between the d(C)nd(G)n duplex and the d(AG)m oligonucleotide as the third strand and carries the CG*A+ protonated base-triads. We have observed such an intermolecular complex between a plasmid carrying the d(C)18 d(G)18 insert and the d(AG)5 oligonucleotide without bivalent cations in 200 mM of Na+ at pH4.0.

[Isolation of recombinant interleukin-3 produced by E. coli].

A synthetic gene coding for human interleukin-3 (hIL3) was cloned in the plasmid pTE2IL3, the gene expression being controlled by the phage fd PVIII promotor and the phage T7 gene 10 translational enhancer. Under constitutive biosynthesis conditions in E. coli, the accumulation of recombinant hIL3 (in the inclusion bodies) was up to 30-40% of the total cell protein.

RNA--protein interactions within the internal translation initiation region of encephalomyocarditis virus RNA.

Various derivatives of the internal ribosomal entry site (IRES) of encephalomyocarditis virus (EMCV) RNA have been used to analyze by UV-cross-linking its interaction with mRNA binding proteins from ascites carcinoma Krebs-2 cells. A doublet of proteins with Mr 58 and 60 kD bound to two regions of the IRES. One site is centered at nt 420-421 of EMCV RNA whereas the other is located between nt 315-377.