Uncertainty and sensitivity analysis of West Java Water Sustainability Index – A case study on Citarum catchment in Indonesia

Water sustainability indices have been recently used to measure the sustainability of water resources within a catchment. Developing a sustainability index involves various steps, some of which have uncertainties associated with them. For the recently developed West Java Water Sustainability Index (WJWSI), three sources of uncertainties were identified, namely uncertainties in the thresholds of non-categorical indicators and sub-indicators, in the weighting schemes, and in the aggregation methods. This paper presents the uncertainty and sensitivity analysis of WJWSI, based on the application of WJWSI to Citarum catchment in West Java, Indonesia. The results of the uncertainty analysis, measured by the coefficient of variation of the thresholds and the sub-indices, indicates that minimum thresholds of Land Use Changes, Coverage, Education, Poverty, Health Impact and Sanitation, and the maximum threshold of Water Quality have higher variation when compared to variation of the other thresholds. The results of the sensitivity analysis, measured by the correlation coefficients between the final index and the thresholds, indicate that changes in the thresholds of WJWSI indicators have not significantly affected the sub-index values of most indicators and sub-indicators. The sensitivity analysis also concluded that either the equal or non-equal weighting scheme can be used for future use of the aggregation of WJWSI indicators and sub-indicators, as changes from equal to non-equal weighting scheme did not significantly affect the final index. However, it was found that the final index values were most sensitive to the aggregation method used (i.e. arithmetic and geometric methods), shown by the significant changes in the final index value when the aggregation method was changed from arithmetic to geometric. The uncertainty and sensitivity analysis presented in this study will not just assist in the efficient use of the WJWSI, but will also help undertake similar analysis for other indices.     

Introducing the Multivariate Dale Model in Population‐Based Genetic Association Studies

Until recently, the most common parametric approaches to study the combined effects of several genetic polymorphisms located within a gene or in a small genomic region are, at the genotype level, logistic regressions and at the haplotype level, haplotype analyses. An alternative modeling approach, based on the case/control principle, is to regard exposures (e.g., genetic data such as derived from Single Nucleotide Polymorphisms – SNPs) as random and disease status as fixed and to use a marginal multivariate model that accounts for inter‐relationships between exposures. One such model is the multivariate Dale model. This model is based on multiple logistic regressions. That is why the model, applied in a case/control setting, leads to straightforward interpretations that are similar to those drawn in a classical logistic modeling framework. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Lethal activity of miconazole in Neisseria gonorrhoeae grown in pure and mixed cultures

Abstract Low concentrations (e.g. 2 × 10⁻⁶ M) of an imidazole derivative anti-fungal agent, miconazole, were lethal for the Gram-negative, facultative aerobic pathogen Neisseria gonorrhoeae grown either alone or in mixed culture with the yeast Candida albicans . Electron microscopic observation of Neisseria cells exposed to miconazole showed the presence of blebs in the outer wall and areas of separation between the wall and the cytoplasmic membrane. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) of cell lysates did not reveal differences in major outer membrane proteins between the treated and the untreated cells of any one strain. Imidazole derivatives are frequently used in the treatment of candidiasis. Our in vitro results show that low concentrations of one of them, miconazole, can be bactericidal for N. gonorrhoeae , a bacterium that can colonise sites of the human body where Candida is often found.     

Site-specific recombination promotes linkage between trimethoprim- and sulfonamide resistance genes. Sequence characterization of dhfrV and sulI and a recombination active locus of Tn21

Summary A new gene for trimethoprim resistance, dhfrV, found in several plasmid isolates with different characteristics, was sequenced and found to correspond to a peptide of 157 amino acids showing 75% similarity with the previously characterized, drug resistant dihydrofolate reductase of type I. The sequenced surroundings of dhfrV in plasmid pLMO20, were found to be almost identical with genetic areas surrounding resistance genes in transposon Tn21 and in R plasmid R388. The trimethoprim resistance genes of pLMO20 and R388 and the spectinomycin resistance gene of Tn21 could be regarded as having been inserted, by recombination, into an evolutionary older structure containg the sulfonamide resistance gene, sulI. The latter gene was sequenced and found to correspond to a peptide of 279 amino acids and with a molecular weight of 30126 daltons. The inserted genes were found to be governed by a promoter situated in the highly conserved structure and also controlling expression of sulI. The insertion points of the different resistance genes were precisely defined, and at the 3 ends of the inserted genes inverted repeats allowing the formation of stem and loop structures were found. Similar structures were found at the 3 ends of the antibiotic resistance genes in Tn7, which could indicate similar recombination mechanisms to be effective in the evolutionary construction of all these different resistance elements.     

Site-specific integration of genes into hot spots for recombination flanking aadA in Tn21 transposons.

Summary Tn21-related transposons are widespread among bacteria and carry various resistance determinants at preferential sites, hs1 and hs2. In an in vivo integrative recombination assay it was demonstrated that these hot spots direct the integration of aminoglycoside resistance genes like aadB from Klebsiella pneumoniae and aacAI from Serratia marcescens, in a recA ^– background. The maximum required recognition sequence which must be present in both the donor and recipient plasmids is 5 CTAAAACAAAGTTA 3 (hs2). The double-site-specific recombination occurred with a frequency of 10^–5–10^–6. The resulting structures include not only replicon fusion products but also more complex structures carrying two copies of the donor plasmid or simply the donor gene flanked by hs elements. hs1 and hs2 are thought to act as recognition sites for a trans-acting site-specific recombinase. By the use of Tn21 deletion derivatives, it has been shown that the recombinase is not encoded by Tn21. This new integrative recombination system is involved in the acquisition of new genes by Tn21-related transposons and their spread among bacterial populations.     

A simple and rapid method for screening bacteria for type II restriction endonucleases: enzymes in Aphanothece halophytica

A method is described which allows a large number of bacterial strains to be rapidly and easily screened for the presence of site-specific endonucleases. The method involves selective permeabilization of the bacterial cell and analysis of the exuded material. Type II restriction endonucleases from cyanobacteria and Gram-negative eubacteria have been detected and new enzymes have been found. The method should be widely applicable and easy to modify for use in genera other than those tested. Three-site-specific endonuclease activities, detected by this method in Aphanothece halophytica PCC 7412, were purified and their recognition and cleavage specificities were determined AhaI and AhaII recognise and cleave the same DNA sequences as CauII and AcyI respectively; the specificity of AhaIII (TTTAAA) has been reported previously (Whitehead and Brown, 1982, FEBS Letters 143:296–300).Abbreviations Brij-58 20 cetyl ether - Pu purine nucleoside - Py pyrimidine nucleoside     

Germanium toxicity in selected bacterial and yeast strains

Summary The toxicity of germanium dioxide (GeO₂) to 21 bacterial and 13 yeast strains was investigated in liquid broth medium to obtain information on strains tolerant to high (1 to 2 mg/ml) GeO₂ concentrations.Arthrobacter sp. NRC 32005,enterobacter aerogenes NRC 2926,Klebsiella aerogenes NCTC 418 andPseudomonas putida NRC 5019 were tolerant to 1 mg/ml GeO₂.Bacillus sp. RC607 was able to grow in the presence of 2 mg/ml GeO₂ at pH 10 in broth culture. The yeastsCandida guilliermondii, Candida shehatae andPachysolen tannophilus were the most sensitive to GeO₂ as evidenced by their diminished growth rates at a GeO₂ concentration as low as 0.1 mg/ml. None of the yeast strains tested exhibited growth in the presence of 1 mg/ml GeO₂. The high pH of the medium containing germanium may be partially responsible for the growth inhibition of the yeast cultures. Select bacterial cultures previously exposed to 1 mg/ml GeO₂ could tolerate and grow better at 2 mg/ml GeO₂, suggesting the existence of very efficient adaptive mechanisms. The pH of the medium could modulate GeO₂ tolerance and this effect was found to be strain-dependent.     

青霉素G酰化酶α亚基Ser177的突变对酶活性的影响

用盒式突变和定点突变对大肠杆菌青霉素G酰化酶α亚基177位ser进行了突变研究,结果发现所挑选的突变体均无酶的活力,这一结果可能可以用来解释Ser 177附近肽段和一些青霉素结合蛋白青霉素结合区在一级结构上保持同源性的原因。     

Identification and characterization of a defective SSV1 genome integrated into a tRNA gene in the archaebacterium Sulfolobus sp. B12

Summary Within the chromosome of the archaebacterium Sulfolobus sp. B12, a 7.4 kb region was identified which displayed extensive sequence similarities to the 15.5 kb genetic element SSV1 carried by the same strain both as a circular form and as a site-specifically integrated copy. DNA sequence analysis indicated that this 7.4 kb region (designated SSV1^intB) represented an SSV1-like element distinguishable from the full-length integrated copy (designated SSV1^intA) by extensive deletions and point mutations. The physical organization of DNA sequences of SSV1^intB indicated that this element was integrated at the same attP site as previously identified for SSV1^intA. A comparison of the DNA sequences at the left attachment sites of SSV1^intA and SSV1^intB revealed that they both represented very similar putative arginine tRNA genes followed by a 10 by inverted repeat sequence. S1 nuclease mapping experiments indicated that these tRNA genes are transcribed. Offprint requests to: W. Zillig     

五种水蛭对不同P^H值的生物效应

本文论述了使用常规试验方法研究5种水蛭:宽身舌蛭(Glossiphonia lata)、八目石蛭(Erpobdella octoculata)、光润金线蛭(Whitmania laevis)、尖细金线蛭(Whitmania acranulata)和日本医蛭(Hirudo nipponia)对12个pH值的24—96小时急性生物效应。结果表明:稻田3个种(尖细金线蛭,光润金线蛭和日本医蛭)均较湖泊近岸2个种(八目石蛭和宽身舌蛭)对pH值的变化要敏感,其中尖细金线蛭最敏感(pH6.0—7.2),八目石蛭的忍耐限度最宽(pH4.0—10.5);当pH值在9.5时,稻田3种水蛭的死亡率在40％以上,其中日本医蛭高达70％;当pH值在3.0时,湖泊近岸2种在24小时内全部死亡,日本医蛭仅死亡10％。日本医蛭是华中农村地区一种主要吸血蛭类,生石灰是一种从稻田消灭蛭类的有效手段,然而水的pH值必须不低于8.6。