Mutagenic evaluation of clonazepam using in vitro and in vivo bacterial tests

The mutagenicity of an anti-epileptic drug, clonazepam, and its metabolites was studied by three repair (rec, pol and uvr) assays and reversion (Ames') tests. No detectable induction of mutation could be found in any tests by them per se or via metabolism in rat and mouse.     

试管出菇法测定刺芹侧耳的交配系统*

在MDA或PNA培养基上,用单孢分离物在试管中进行配对,观测菌丝体上的锁状联合和子实体的形成情况,判定单孢菌株间的亲和性;研究了2个刺芹侧耳菌株PE-11、PE-12和1个糙皮侧耳菌株PO-02的交配系统,以及3个菌株间的亲缘关系;结果表明刺芹侧耳和糙皮侧耳是双因子交配系统。这是一个测定侧耳属的交配系统的新方法。     

Mutation and nuclear stage in Schizosaccharomyces pombe I. An experimental approach to the role of recombination in mutation induction

A reverse mutation system using G1 and G2 cells of Schizosaccharomyces pombe is described. In order to enable the system to deal with the problem of mutation dependence on recombination, tests were performed on (i) the homogeneity of cell populations with respect to nuclear stage; (ii) the fate of cells during post-irradiation incubation; (iii) the colony-forming ability of G1 and G2 revertants, and (iv) cell viability on the mutation plates. On the basis of the results, it is thought that, using this system, information can be obtained on the role of recombinational events in the process of mutation induction.     

Characterization of chemically induced mutations in the ad-I locus of Schizosaccharomyces pombe

An attempt to assess the frequencies of mutations of the base-pair substitution type and of the addition/deletion type was undertaken in 64 ICR-170-, 28 MNNG- and 50 EMS-induced ad-1 mutant strains of Schizosaccharomyces pombe.By using temperature sensitivity, osmotic remediability, and interallelic complementation, sensitivity to nonsense suppressors and revertibility tests with 2-methoxy- 6-chloro-9-[3-(ethyl-2-chloroethyl)aminopropylamino]acridine dihydrochloride (ICR-170) and N-methyl-N′-nitro-N-nitrosoguanidine (MNNG) as diagnostic criteria to distinguish between the two types of alterations, the following conclusions were reached: (1) The mutational alteration in all of the MNNG-induced and in at least 74% of the ethyl methanesulfonate(EMS)-induced mutant strains is of the base-pair substitution type; (2) Both types of mutation were found amongst ICR-170-induced strains.     

Genetic analysis of replicating instabilities in yeast

Strains showing ethyl methanesulfonate (EMS)-induced replicating instability were genetically analysed to test whether within a given line, mosaics from different plating generations carry a mutation at the same site within the locus. A forward mutation system involving five loci controlling adenine biosynthesis in Schizosaccharomyces pombe was used. Genetic analysis was carried out by interallelic complementation and intragenic recombination tests. The data showed that EMS-induced instabilities are site-specific in being confined to the same recombination unit. This finding is discussed in relation to the possible mechanism(s) of replicating instabilities after different mutagenic treatments in a variety of biological systems.     

A novel agar medium to detect hydrogen peroxide-producing bacteria based on the prussian blue-forming reaction

The classic method for H(2)O(2) detection involving Prussian blue formation was adapted to formulate a novel agar medium that makes possible in situ detection of H(2)O(2) produced by bacteria. Using this medium, colonies of H(2)O(2)-producing species including Streptococcus pyogenes were easily identified by the appearance of blue halos. The utility of the medium was further illustrated by its successful application to the isolation of H(2)O(2)-producing mutants from a non-H(2)O(2)-producing stain of S. pyogenes.     

Improved performance of the modified Hodge test with MacConkey agar for screening carbapenemase-producing Gram-negative bacilli

The detection of carbapenemases in Gram-negative bacilli is important for optimal patient treatment and to control spread of the resistance. The modified Hodge test can detect carbapenemase-producing Gram-negative bacilli. In this study, we compared the performance of MacConkey agar and Mueller-Hinton agar for metallo-β-lactamase (MBL) and OXA carbapenemase screening. Overall, the performance of Hodge test was better with MacConkey agar due to enhanced release of β-lactamases from the cells in the presence of bile compounds. Concomitant use of the modified Hodge test could resolve most of the problems with uncertain double-disk synergy tests in MBL detection.     

Optimization of culture media for in vitro rooting of Malus domestica Borkh. cv. Compact Spartan

Shoots of Malus domestica Borkh. cv. Compact Spartan raised in vitro do not root in a single auxin medium. Components of the rooting medium were tested not only for root initiation but also for root elongation. Root emergence and further growth were inhibited by a too prolonged auxin treatment, the presence of NH4NO3 and the lack of substrate aeration. Saccharose was essential to achieve highly reproducible root growth on agar but was not necessary on watered vermiculite. Ca(NO3)2 stimulated root initiation, emergence and growth and improved their viability. This revised version was published online in July 2006 with corrections to the Cover Date.     

A porous agar medium for improving the growth of plants under sterile conditions

Porous nutrient agar was prepared under sterile conditions by drawing molten 3.5% (w/v) nutrient agar into a plastic syringe, allowing it to set, extruding it into a test tube and giving the tube a firm flick. Simple colorimetric tests showed that gaseous diffusion was substantially faster through 3.5% (w/v) porous agar than through the 1% (w/v) non-porous agar frequently used for growing plants under sterile conditions. Root systems ofTrifolium subterraneum grew 80–90% larger in porous than in non-porous agar.     

Effects of phosphate and nitrate supply on productivity,agar content and physical properties of agar ofGracilaria strain G-16S

Gracilaria strain G-16S was cultured in various phosphorus (P) supply rates with low or high nitrogen (N) supply to determine the effects of nutrient supply on its productivity, agar content and physical properties of the agar. Productivity was reduced after four weeks of growth in zero P supply as plants reached 0.07% P tissue content (critical level), with fragmentation of these plants by six weeks (0.05% P; minimum viable level). Native agar content was higher in low P and high N, or low N conditions. Agar content appeared to increase with decreasing P under high N supply. This increase was not apparent with alkali treatment prior to extraction. Agar gel strength was greatly increased by alkali treatment. The highest gel strengths were obtained under high N supply at all P supply rates except zero P, and under low N supply at 12 M P week^–1. Native agar gel strengths showed a similar pattern on a lower scale. Melting temperatures were higher in agars with higher gel strengths. Dynamic gelling temperatures were generally high for alkali-treated agar, with agar from plants grown in zero P supply showing a slightly elevated gelling temperature. Melting and gelling temperatures of native agars with the highest gel strengths were in the same range as bacteriological agar. These results show that P and N supply affects productivity, agar content and agar physical properties, but the tradeoffs between a slightly higher agar quantity under nutrient limitation and higher agar quality under nutrient-replete conditions seem to favor the latter.     

Comparison of plate count agar and R2A medium for enumeration of heterotrophic bacteria in natural mineral water

In order to recover as many viable bacteria as possible from natural mineral water, in this study we have compared the counts obtained with the standard method (pour plate procedure with Plate Count Agar (PCA)) and counts with alternative test methods (PCA/spread plates, R2A medium/pour plates and R2A medium/spread plates). The results showed that counts with R2A medium/spread plates at 22°C and after a 7-day incubation period were more than 343% higher than those obtained with PCA/pour plate method. At 37°C and after a 3-day incubation period, the R2A pour plate technique gave counts about 368% greater than for the standard method. Moreover, while Pseudomonas, Comamonas and Acinetobacter species were isolated both from PCA and R2A medium, Flavobacterium spp. and Arthrobacter spp. were isolated only from R2A medium. For its higher productivity, R2A medium should be recommended for heterotrophic plate counts in natural mineral water.     

Evaluation of acid phosphatase as a confirmation test for Clostridium perfringens isolated from water

AIMS: To evaluate testing for acid phosphatase as an alternative method for the confirmation of Clostridium perfringens isolated from water. METHODS AND RESULTS: Sixty-two reference strains of Clostridium were tested for their ability to produce acid phosphatase, as well as reduction of sulfite on tryptose sulfite cycloserine agar (TSC) and production of fluorescence in TSC supplemented with 4-methylumbelliferylphosphate (MUP). Additionally 155 environmental presumptive C. perfringens isolates from TSC incubated at 44 degrees C were identified and tested for acid phosphatase production and by the conventional MNLG (testing for motility, nitrate reduction, lactose fermentation and gelatin liquefaction) confirmation procedure. Twenty-seven strains from 15 species of Clostridium-reduced sulfite to some extent on TSC incubated at 44 degrees C, with a significant number of species being able to grow well at this temperature, indicating that a confirmation step is needed for the enumeration of C. perfringens on this medium. All 10 strains of C. perfringens tested, together with one strain each of Clostridium baratii and Clostridium rectum produced acid phosphatase. These also produced fluorescence on MUP supplemented TSC, as did 13 strains of acid phosphatase negative, sulfite-reducing clostridia, representing nine species. Of the environmental isolates, 114 were identified as C. perfringens of which 108 (94.7%) were confirmed by the acid phosphatase test compared with 104 (91.2%) by the MNLG tests. CONCLUSIONS: Testing for acid phosphatase production is at least as reliable, and much simpler to perform, than the current standard confirmation MNLG procedure. Incorporation of MUP into TSC does not reliably improve the identification of presumptive C. perfringens. SIGNIFICANCE AND IMPACT OF THE STUDY: Application of testing for acid phosphatase as a confirmation test for C. perfringens would substantially simplify the analysis for this bacterium from water samples, and reduce the analysis time to confirmed counts.     

Chloramphenicol and florfenicol susceptibility of fish-pathogenic bacteria isolated in France: comparison of minimum inhibitory concentration, using recommended provisory standards for fish bacteria

AIM: To investigate the distribution of antimicrobial resistance to phenicols in the fish pathogenic bacteria Aeromonas salmonicida, motile Aeromonas, Yersinia ruckeri, lactic bacteria and the nutritionally fastidious Flavobacterium psychrophilum. The last species was screened on two media (diluted Mueller-Hinton and peptone-enriched Anacker and Ordal), both supplemented with horse serum. METHODS AND RESULTS: Minimal inhibitory concentration (MIC) assessment, using the agar dilution method according to proposed standards, confirmed that chloramphenicol resistance was more frequent and expressed at higher levels than florfenicol resistance. A significant resistant population, highlighted by the bimodal distribution of MICs, was detected only for chloramphenicol in A. salmonicida. No link could be found with the geographical origin of the isolates or fish species. Other cases of resistance appeared randomly distributed or related to the natural properties of the bacterial species. Although the two media used for testing F. psychrophilum resulted in comparable performances in dilution methods, Anacker and Ordal was more adapted to disc diffusion tests. CONCLUSION: Despite wide use, resistance to florfenicol does not seem to occur frequently in French fish farms. SIGNIFICANCE AND IMPACT OF THE STUDY: It is important to maintain a surveillance, as development of florfenicol resistance has occasionally been documented. For this purpose, and for the species studied in this work, the recently proposed standards appear generally well-adapted.     

Supporting material affects the growth and development of in vitro sweet potato plantlets cultured photoautotrophically

Summary A comparative study was conducted to optimize the vegetative growth of sweet potato (Ipomoea batatas L. (Lam), cv. Beniazuma) plantlets cultured in vitro in five different types of supporting materials: agar matrix (a seaweed derivative; Kanto Chemical Co. Inc., Tokyo), gellan gum (a Pseudomonas derivative; Kanto Chemical Co. Inc., Tokyo), vermiculite (a kind of hydrous silicates), a mixture of vermiculite and cellulose fiber (Florialite; Nisshinbo Industries, Inc., Tokyo) and cellulose plug (Sorbarod; Baumgartner Rapiers SA., Switzerland). Single nodal cuttings were cultured photoautotrophically (without any sugar in the medium and with enriched CO₂ and high photosynthetic photon flux) for 21 d on MS basal medium. Plantlets exhibited the greatest growth when Florialite was used as supporting material. The leaf and root fresh and dry mass were 2.4× and 2.9×, and 2.2× and 2.8× greater, respectively, than those of the plantlets grown in the agar matrix (control). Plantlets cultured in Sorbarod supporting material exhibited the second greatest fresh and dry mass of leaves and roots followed by vermiculite and gellan gum supporting material. The most interesting feature was the development of a large number of fine lateral roots from the main adventitious root in the Florialite treatment. Among the treatments, the highest net photosynthetic rate was evident in the Florialite grown plantlets. The percent porosity of the supporting materials was highest in Sorbarod followed by Florialite and vermiculite. Plantlets transplanted from the Florialite supporting material exhibited the highest acclimatization percentage followed by that of the Sorbarod treatment.     

青岛近岸海水及几种海产品中副溶血弧菌(Vibrio parahaemolyticus)生境的调查

副溶血弧菌是水产食品中的一种重要食物中毒菌,它在沿岸海水和海产动物体上都有广泛的分布,所以它又是海产动物的一种条件性致病菌。本文报告了该菌在青岛近岸海水和几种常见的水产食品上污染了该菌的情况,在检测方法上也进一步修定了一种选择性较强的培养基(SAC)。调查发现青岛近岸海水中副溶血弧菌的出现率为68～463CFU/100ml,几种常见海产食品中平均含量值为745～6900CFU/100克,其中贝类含量最高达6900/100克。采用常用的选择培养基“TCBS”等与修定的“SAC”对该菌进行检测比较,结果表明“SAC”法较“TCBS”法检出的阳性率和灵敏性均较高,两种方法X~2=4.28,P>0.05,效果有显著的意义。     

A marketing approach to agar

Agar has, with the exception of certain retail markets in the Far East, specifically Japan, traditionally been sold to the industrial user. Small quantities are consumed in Islamic countries during Ramadan and in the Germanic countries as a food thickener and a laxative. However, outside of Japan, no significant marketing effort has ever been undertaken with a view to increase the demand for agar by consumers.A marketing plan is suggested to change this situation. All possible uses for agar by the consumer have been identified and studied. The special features of the product, together with certain packaging, are highlighted. Potential markets for these features are identified. Strategies for the development of these markets have been developed. The overall plan is now in a state of final review and just prior to implementation. The product launch should generate a significant consumer awareness which will translate into demand, thereby increasing the market for agar in various forms, formulations and packagings.     

A model for tumorigenicity and metastatic potential: Growth in 1.0% agar cultures

Summary We developed a method to determine the amount of work performed by cells through cell division in 1.0% agar cultures. There was no correlation between the cloning efficiencies of 1.0 and 0.3% agar cultures. Growth in 1.0% agar cultures correlated well with such malignant properties as tumorigenicity and the invasive and metastatic potentials. Our method revealed that metastatic MC and F cell lines possess different means of taking advantage of energy to proliferate against an environmental pressure from those possesed by nontumorigenic (ME and T-C3H) cell strain/line or nonmetastatic but tumorigenic (L, MR, and magc₁) cell lines.     

Development of Dactylaria eudermata Drechsler a predaceous fungi in Meloidogyne incognita

Dactylaria eudermata Drechsler is one of the important predaceous fungi occurring widely in different soils. The fungus produces hyphal bails and network compound in which nematodes are entangled. This hyphal nets as trapping structure which may be single dimensional to two or three dimensional and are formed through repeated hyphal anastomosis, which capture nematodes either through the adhesive material present on the surface of hyphal nets or due to physical entanglement. In the experiment it was observed that inflation of hyphal bails takes 30 to 50 minutes and capturing and killing the nematode by a single conidia in water takes 35–55 hours, were as time required for inflation of hyphal bails and real trapping and killing of a nematode in maize meal (MMA: water (1:10) medium) takes one minute and 30–50 hours respectively.     

泥浸汁对太湖沉积物中的好氧可培养细菌多样性的影响

【目的】研究添加泥浸汁与否对太湖沉积物中可培养细菌的影响。【方法】采用R2A培养基和添加泥浸汁R2A培养基对沉积物中细菌进行分离培养,16S r RNA基因系统发育分析比较种群结构。【结果】培养基中添加泥浸汁,可使可培养细菌的种类数量增加到1.6倍。16S r RNA基因序列分析表明,培养的优势细菌类群存在明显差别。R2A培养基上生长的细菌主要为厚壁菌门(52%)、放线菌门(24%)、变形菌门(20%)和拟杆菌门(4%),其中大部分细菌与芽孢杆菌属、假单胞菌属、节杆菌属等关系密切;而添加泥浸汁的R2A培养基上生长的细菌则主要为变形菌门(40%)、放线菌门(35%)、厚壁菌门(22.5%)和拟杆菌门(2.5%),与鞘脂单胞菌属、芽孢杆菌属、副球菌属、节杆菌属等关系密切。【结论】添加泥浸汁原始营养因子可提高沉积物中可培养细菌的多样性,提高菌种可培养效率。     

UMPU and Alternative Tests for Association in 2 × 2 Tables

The use of the uniformly most powerful among the unbiased (UMPU) test was recently suggested for the study of gametic association between two polymorphic loci as an alternative to the Fisher's exact test (Zapata and Alvarez, 1997, Annals of Human Genetics 61, 71-77). However, the proposed test is not UMPU for two-sided alternatives. In this study, we present the UMPU test, discuss criticisms against the use of randomized tests, and compare the power of several tests. We show that, in many practical cases, the use of the UMPU test is less than desirable and propose the alternative adjusted-more extreme tables (A-MET) and the equal-tails (ET) tests. We suggest that some of the general arguments against the use of randomized tests can be alleviated by a newly proposed extended p-value definition.