Plating Medium for Differentiating Salmonella arizonae from Other Salmonellae

A differential plating medium developed for isolation of Salmonella arizonae produces a uniform reaction for both lactose-negative and -positive S. arizonae and differentiates S. arizonae from other salmonellae.     

An Estimation Procedure for the Joint Distribution of Spatial Direction and Thickness of Flat Bodies Using Vertical Sections. Part II: An application in soil micromorphology

In soil micromorphology fissures are considered in vertical sections. To get information about the properties of the soil the joint distribution of spatial direction and width of these fissures is of interest. The fissures are mathematically generalized to flat bodies which are defined as stationary weighted surface processes with the weight “thickness”. In a typical point of the surface process suitable, joint parametric distributions of direction and thickness are assumed. The parameters have to be estimated from measurements on vertical sections which are taken from the soil. On these sections only a visible thickness and a visible angle can be observed. The joint distribution of these variables can be expressed by the joint distribution of spatial direction and thickness with the same parameters and in this indirect way the parameters can be estimated. The paper describes how to randomize the vertical section and how to measure the visible variables on the sections. The Chi-Square method is proposed for the parameter estimation. Further it is discussed how to derive good starting values for the numerical procedure. All this is demonstrated in a simulation study using the Bingham-Mardia distribution for the direction and the lognormal distribution for the thickness including a way to correlate the mean thickness and the direction. Finally an application in soil micromorphology is demonstrated for one soil horizon.     

The oncolytic peptide LTX-315 triggers necrotic cell death

The oncolytic peptide LTX-315 has been designed for killing human cancer cells and turned out to stimulate anti-cancer immune responses when locally injected into tumors established in immunocompetent mice. Here, we investigated the question whether LTX-315 induces apoptosis or necrosis. Transmission electron microscopy or morphometric analysis of chromatin-stained tumor cells revealed that LTX-315 failed to induce apoptotic nuclear condensation and rather induced a necrotic phenotype. Accordingly, LTX-315 failed to stimulate the activation of caspase-3, and inhibition of caspases by means of Z-VAD-fmk was unable to reduce cell killing by LTX-315. In addition, 2 prominent inhibitors of regulated necrosis (necroptosis), namely, necrostatin-1 and cycosporin A, failed to reduce LTX-315-induced cell death. In conclusion, it appears that LTX-315 triggers unregulated necrosis, which may contribute to its pro-inflammatory and pro-immune effects.     

Plague Meningitis—A Retrospective Analysis of Cases Reported in the United States, 1970-1979

Meningitis caused by Yersinia pestis developed in 6 (6%) of a total of 105 patients with plague reported to the Centers for Disease Control from 1970 to 1979. Five of the six cases occurred in children aged 10 to 15 years. All six patients received antibiotic therapy before meningitis developed, which appeared between the 9th and 14th days after the onset of acute illness in five of the six patients. There were no neurologic sequelae. The antigenic and biochemical profiles of the Y pestis strains isolated from cerebrospinal fluid in the meningitis cases did not differ from those of the Y pestis strains obtained from blood and bubo aspirates in the other 99 patients, and neither did in vitro studies suggest antibiotic resistance. While plague meningitis is an uncommon complication of acute plague infection, physicians in the western United States should be aware that it may develop as much as 14 days after antibiotic therapy for the acute plague infection has been initiated.     

Transformation of toluene and benzene by mixed methanogenic cultures

The aromatic hydrocarbons toluene and benzene were anaerobically transformed by mixed methanogenic cultures derived from ferulic acid-degrading sewage sludge enrichments. In most experiments, toluene or benzene was the only semicontinuously supplied carbon and energy source in the defined mineral medium. No exogenous electron acceptors other than CO2 were present. The cultures were fed 1.5 to 30 mM unlabeled or 14C-labeled aromatic substrates (ring-labeled toluene and benzene or methyl-labeled toluene). Gas production from unlabeled substrates and 14C activity distribution in products from the labeled substrates were monitored over a period of 60 days. At least 50% of the substrates were converted to CO2 and methane (greater than 60%). A high percentage of 14CO2 was recovered from the methyl group-labeled toluene, suggesting nearly complete conversion of the methyl group to CO2 and not to methane. However, a low percentage of 14CO2 was produced from ring-labeled toluene or from benzene, indicating incomplete conversion of the ring carbon to CO2. Anaerobic transformation pathways for unlabeled toluene and benzene were studied with the help of gas chromatography-mass spectrometry. The intermediates detected are consistent with both toluene and benzene degradation via initial oxidation by ring hydroxylation or methyl oxidation (toluene), which would result in the production of phenol, cresols, or aromatic alcohol. Additional reactions, such as demethylation and ring reduction, are also possible. Tentative transformation sequences based upon the intermediates detected are discussed.     

Macrophages from endotoxin-hyporesponsive (Lpsd) C3H/HeJ mice are permissive for vesicular stomatitis virus because of reduced levels of endogenous interferon: possible mechanism for natural resistance to virus infection.

The C3H/HeJ mouse strain bears an autosomal gene defect, Lpsd, which results in a greatly diminished capacity to respond to endotoxin, the ubiquitous lipopolysaccharide derived from the cell walls of gram-negative bacteria. These mice also exhibit greater susceptibility to a variety of viral and bacterial infections than syngeneic, fully lipopolysaccharide-responsive (Lpsn) mouse strains and possess macrophages with defects in differentiation which are reversed by treatment with exogenous interferon (IFN). To test directly the hypothesis that C3H/HeJ macrophages are deficient in endogenous IFN levels, macrophages from C3H/HeJ (Lpsd) and C3H/OuJ (Lpsn) mice were compared for sensitivity to vesicular stomatitis virus. At a multiplicity of infection of 0.1, C3H/OuJ macrophages were completely refractory to infection, whereas C3H/HeJ macrophages were permissive for replication, and infection resulted in 100% cytopathic effect. These findings were confirmed with a second inbred Lpsn and Lpsd strain pair. Levels of 2',5'-oligoadenylate synthetase were significantly higher in Lpsn cells. C3H/HeJ macrophages, derived from bone marrow precursors under the influence of macrophage colony-stimulating factor, shown previously to induce IFN in macrophages, were as refractory as C3H/OuJ macrophages. Exposure of nonpermissive macrophages to anti-IFN-alpha/beta antibody prior to infection rendered cells permissive. Our findings suggest that endotoxin provides a primary stimulus for the maintenance of normal macrophage differentiation and innate resistance via the induction of endogenous IFN by macrophages.