Regional distribution of DNA and RNA in rat brain: A sensitive determination using high-performance liquid chromatography with electrochemical detection

DNA and RNA contents in 20 brain regions or nuclei of the rat were determined by a highly sensitive method using high-performance liquid chromatography with electrochemical detection. The high DNA and RNA contents were found in the hypothalamic nuclei, especially the median eminence-arcuate nucleus. These results may be available for the preparation of nucleic acids as the regional control.     

Antibiotic production by the marine photosynthetic bacterium Chromatium purpuratum NKPB 031704: localization of activity to the chromatophores

Abstract Over 200 strains of marine purple photosynthetic bacteria were isolated. Two strains showed antibiotic activity towards Saccharomyces cerevisiae and were tentatively identified as Chromatium purpuratum . Crude antibiotic, prepared by solvent extraction, showed a broad antimicrobial spectrum. The highest activity was found in the chromatophore fraction. Chromatographic separation of purified light harvesting complex from one strain, NKPB 031704, showed the presence of two separate pigmented compounds which were responsible for antimicrobial activity. Our findings reveal the unexpected ability of photosynthetic bacteria to produce broad spectrum antibiotics. In addition, this is the first example of intracellular localization of antibiotic activity in a marine bacterium.     

Nalidixic acid-resistant mutations of the gyrB gene of Escherichia coli

Summary DNA fragments of 3.4 kb containing the gyrB gene were cloned from Escherichia coli KL-16 and from spontaneous nalidixic acid-resistant mutants. The mutations (nal-24 and nal-31) had been determined to be in the gyrB gene by transduction analysis. Nucleotide sequence analysis of the cloned DNA fragments revealed that nal-24 was a G to A transition at the first base of the 426th codon of the gyrB gene, resulting in an amino acid change from aspartic acid to asparagine, and nal-31 was an A to G transition at the first base of the 447th codon, resulting in an amino acid change from lysine to glutamic acid. This indicates that mutations in the gyrB gene are responsible for nalidixic acid resistance.     

Promotion of Rooting in Azukia Cuttings by Possible Glycoproteins Extracted from Lentinus edodes Culture

Macromolecules purified from Lentinus edodes mycelia cultureenhanced adventitious root formation in Azukia epicotyl cuttings.Partial purification by sequential column chromatographies gavematerial composed of 71% polysaccharides and 29% proteins. Thesugar moiety consisted of mainly xylose, glucose and arabinose,the sum of their contents being more than 76% of the total carbohydrates.The protein moiety consisted of mainly glycine and serine, whichaccounted for more than 40% of the total amino acid residues. (Received June 9, 1984; Accepted November 12, 1984)     

Water-soluble glucans from the seed of Coix lacryma-jobi var. ma-yuen

The water-soluble major polysaccharides from the seed of Coix lacryma-jobi var. ma-yuen eluted as a broad peak by gel filtration on Sepharose CL-2B. The mixture (CS-Glucan) was resolved into 7 glucans by HPLC on the column of Asahi-Pak GS-510 + GS-320. Similarities were observed between M, shown in the gel filtration profile and the elution volume in HPLC. Methylation analysis indicated that the ethanol-fractionated CS-glucan contained 4-O- and 4,6-di-O-substituted glucosyl residues. ¹H and ¹³C NMR data accorded with the results of methylation analysis, and the glycosidic linkages were shown to have an α-configuration. Thus, CS-glucan contained (1 → 4) linked α-d-glucans to which are attached glucosyl side chains at O-6 of the main chain in a similar way to amylopectin. Each purified glucan was shown to have different absorption maxima ( > 550 nm or 530 nm) in the iodine reaction. The results of the methylation analysis and of the pullulanase digestion suggest that the 550 nm-glucan has a lower branching frequency and shorter side chains than the 530 nm-glucan. Although CS-glucan was found to have weak anti-complementary activity, HPLC-purified > 550 nm-glucan was found to be more potent than the 530 nm-glucan. Thus CS-glucan is highly heterogeneous, and the glucans which form a tight complex when tested with iodine, generally tend to have considerable anti-complementary activity.     

Nitrate and Other Anions in the Rice Phloem Sap

The anionic composition was determined for pure rice phloemsap which had been collected from brown planthopper styletsby cutting them with a YAG laser beam. The most abundant inorganicanion was Cl^– at 52.1 mM. PO₄^3– and SO₄^2–were found at 8.1 mM and 1.8 mM, respectively. NO₃^– waspresent at 1.9 mM when the rice had been grown with nutrientsolution containing 0.35 m of NO₃^– The phloem sap alsocontained malic, succinic and citric acid at 7.3, 3.0 and 3.2mM respectively. Small amounts of other organic acids were alsofound. (Received October 4, 1984; Accepted December 14, 1984)     

A photosystem other than PS370 also mediates the negative phototaxis of Halobacterium halobium

Abstract It was found that a photorepellent system other than photosystem 370 (PS370) also controls the behavior of Halobacterium halobium . Both the dependence of background illumination and wavelength where the response showed maximum action distinguished that photosystem from PS370 whose photoreceptor pigment is thought to be an intermediate of s-rhodopsin (sR). A mutant strain that has no detectable activity in PS370 and in photoattractant response was isolated. This mutant strain showed the repellent response due to the new photosystem.     

Evidence that cyclic AMP may regulate Ca2+-mobilization and phospholipases in thrombin-stimulated human platelets

The regulation of human platelet responses by cyclic AMP (cAMP) has been investigated by measuring thrombin-stimulated serotonin release, Ca²⁺ uptake and phospholipase activity. Thrombin-induced 1,2-diacylglycerol (DG) formation as a result of phospholipase C activation was inhibited by pretreatment with dibutyryl cAMP (dbcAMP) in a dose-dependent manner. Subsequent failure to produce phosphatidic acid (PA), which is converted from 1,2-DG by phosphorylation and would serve as intracellular Ca²⁺ ionophore, appeared to parallel the decrease in Ca²⁺ uptake activity. Phospholipase A₂ activity, monitored by the production of [³H]lysophosphatidylcholine and [³H]lysophosphatidylethanolamine, was also suppressed by dbcAMP. These data indicate that the intracellular cAMP level may be closely associated with Ca²⁺ uptake and phospholipases activation. In addition, it is suggested that alteration of intracellular cAMP regulates phospholipase activation and consequently platelet responses, perhaps by controlling available Ca²⁺ content.     

Isolation and Characterization of an Escherichia coli ruv Mutant Which Forms Nonseptate Filaments After Low Doses of Ultraviolet Light Irradiation

Two ultraviolet light (UV)-sensitive mutants have been isolated from Escherichia coli K-12. These mutants, designated RuvA(-) and RuvB(-), were controlled by a gene located close to the his gene on the chromosome map. They were sensitive to UV (10- to 20-fold increase) and slightly sensitive to gamma rays (3-fold increase). Host cell reactivation, UV reactivation and genetic recombination were normal in these mutants. Irradiation of the mutants with UV resulted in the production of single-strand breaks in deoxyribonucleic acid, which was repaired upon incubation in a growth medium. After UV irradiation, these mutants resumed deoxyribonucleic acid synthesis at a normal rate, as did the parent wild-type bacteria, and formed nonseptate, multinucleate filaments. From these results we concluded that the mutants have some defect in cell division after low doses of UV irradiation, similar to the lon(-) or fil(+) mutant of E. coli. The ruv locus was divided further into ruvA and ruvB with respect to nalidixic acid sensitivity and the effect of minimal agar or pantoyl lactone on survival of the UV-irradiated cell. The ruvB(-)mutant was more sensitive to nalidixic acid than were ruvA(-) and the parent strain. There was a great increase in the surviving fraction of the UV-irradiated ruvB(-) mutant when it was plated on minimal agar or L agar containing pantoyl lactone. No such increase in survival was observed in the ruvA(-) mutant.