Detection and mapping of six miniF-encoded proteins by cloning analysis of dissected miniF segments

Summary Various DNA subfragments were derived from miniF DNA by complete or partial PstI cleavage, and cloned in the plasmid vectors pBR322 or dv1. The recombinant plasmids obtained were introduced into an Escherichia coli minicell-producing strain, and the plasmid-coded proteins were radiolabeled and analyzed by gel electrophoresis. Six miniF-encoded proteins, larger than 11 000 daltons, were detected and their coding regions were mapped on the F plasmid genome. Three of them were assigned by taking into account the known nucleotide sequences (Murotsu et al. 1981; K. Yoshioka, personal communication). The coding directions of some proteins were determined by inserting the lac promotor into one of the recombinant plasmids and analyzing the increase in production of the proteins. The coding direction of the five proteins analyzed so far was uniform. Comparison of these results with a functional map of miniF suggested possible roles of the proteins.     

Fungal contamination and mycotoxin-producing potential of dried beans

A total of 604 samples of about 7 different types of beans was examined to determine their mycological profiles, and suitability for use as solid substrates for mycotoxin production.All of the samples were collected from bean jam makers in Tokyo by the official food examiners.Genera Penicillium and Aspergillus were predominant, and genus Wallemia was also found commonly in all types of beans.Mycotoxin-producing Aspergillus strains were isolated from 52 samples of beans, approximately 9% of the total. The highest incidence of toxigenic Aspergillus (14.1%) was found in kidney beans. Red beans and peas inoculated with Aspergillus ochraceus were found to produce about 7 to 8 times more toxin than was obtained in a liquid medium, and red beans inoculated with A. versicolor produced more toxin than was obtained in yeast extract sucrose broth. Green peas inoculated with Fusarium graminearum produced about 8 times more T-2 toxin than was obtained in 1% peptone containing Czapek solution under comparable culture conditions.     

Purification and properties of a lambda operator-binding protein which is expected to be autorepressor (tof protein) from E. coli carrying lambdadv plasmid.

Summary In order to study the mode of action of the tof gene product, which is an autorepressor of the bacteriophage and plasmid dv, we have purified a DNA-binding protein which is specifically produced in bacteria carrying dv. This protein possesses characteristics expected for the product of the tof gene, since it is produced under conditions where cI-repressor is not made, and since it binds to oL and oR operators on the phage genome. The molecular weight of the native protein is 16,000–17,000 daltons, and the monomeric molecular weight as measured by gel electrophoresis in the presence of sodium dodecyl sulfate is about 10,000 daltons. Denaturation and renaturation experiments demonstrated that the native protein is a dimer of 10,000-dalton monomers. The DNA-specific binding protein is not produced in cells carrying i ²¹dv or 80dv.     

On mechanisms of removing astringency in persimmon fruits by carbon dioxide treatment I. Some properties of the two processes in the de-astringency

Carbon dioxide treatment of persimmon fruit (Diospyros KakiL., cv. "Hiratanenashi" astringent type) at 20?C for 24 hr,at 30?C for 12 hr, or at 40?C for 6 hr followed by storage inair at 30?C for 3 days produced de-astringent fruit of excellentquality without abnormal softening. The induction process inthe anaerobic atmosphere had a Q₁₀ of ca. 2.0 and the subsequentde-astringency process, which proceeded either in air or carbondioxide, had Q₁₀ of ca. 1.4. During the short gas treatment(at 40?C for 6 hr) the ethanol content increased rapidly andreached a maximum of 28.0 mg and the acetaldehyde content graduallyreached 0.443 mg per fruit, whereas the soluble tannin(s) contentdecreased rapidly to two-thirds of its initial level. Therewas a lag period of 3 hr in the decrease of soluble tannin(s).Dimedon and sodium bisulfite, as well as sodium fluoride, inhibitedde-astringency. The mechanisms of removing astringency in thisfruit are discussed. (Received June 3, 1976; )     

Linkage of Mercury, Cadmium, and Arsenate and Drug Resistance in Clinical Isolates of Pseudomonas aeruginosa

Of the 787 isolates, 99.8% were metal resistant, with most (99.5%) showing multiple resistance. Fifty-three percent of the isolates were both metal and drug resistant, whereas only 19% were metal resistant and drug sensitive.     

Growth of the hydrocarbon-rich microalga Botryococcus braunii in secondarily treated sewage

Summary A hydrocarbon-rich green microalga, Botryococcus braunii, was able to grow well in secondarily treated sewage (STS) from domestic waste-water in a batch system. The growth in STS from domestic waste-water was as good as in the common artificial medium of modified Chu 13 and its hydrocarbon contents were high enough at 53% and 40% compared with 58% in the case of the modified Chu 13 medium. B. braunii utilized nitrate from 7.67 or 4.48 mg/l to a level below detection of < 0.01 mg/l in STS. After this consumption of nitrate, nitrite was consumed, and ammonium was not. Phosphate, even at an extremely low concentration, was also consumed by B. braunii. These results show the possibility of using STS as a medium to grow B. braunii and for removal of nitrogen and phosphorus by algal consumption in STS.Correspondence to: S. Yokoyama     

Stabilities of Clostridium botulinum type B and C toxins in ruminal contents of cattle.

Purified L (large) toxins of Clostridium botulinum type B and C are more stable than M (medium) toxins in ruminal contents of cattle. That finding suggests that the stabilities of L toxins are in part responsible for the incidence of intoxication of cattle.     

Toxin production by Clostridium botulinum in grass.

Investigations on farms where botulism has occurred in cows showed that proteolytic Clostridium botulinum type B was present in newly made grass silages. Experiments were undertaken to study growth and toxin production of C. botulinum in grass. Of the strains tested only proteolytic strains of C. botulinum types A and B were able to produce toxin with grass as a substrate. Proteolytic strains of type B produced both medium (12S) and large (16S) toxin forms. The minimal water activity (aw) for toxin production at pH 6.5 and 5.8 was 0.94. At pH 5.3, toxin was produced at an aw of 0.985. These results indicate that proteolytic strains of C. botulinum (if present) may multiply and produce toxin in wilted grass silages.