bluuebunny/crossref_metadata_2025 huggingface dataset:
Purification and characterization of the tyrosinase of Streptomyces michiganensis DSM 40015
Authors: Philipp Stephan , Held Thomas , Kutzner Hans J.
Published: February 2007

Tyrosinase of Streptomyces michiganensis DSM 40015 was purified 61‐fold from the culture broth: After a fractionated ammonium sulfate precipitation the enzyme was separated by hydrophobic interaction chromatography with Phenyl‐Sepharose and ionic interaction chromatography with CM‐Cellulose; finally a gel filtration with Sephadex G‐75 yielded 1.7% of the originally existent enzyme. SDS gel‐electrophoresis of the purified enzyme showed two bands representing a size of 34500 and 32000 dalton, respectively. However, by isoelectric focussing only one band could be found exhibiting an isoelectric point of approximately 9.0. Temperature and pH‐optimum of the enzyme activity were 33°C and pH 7.0, respectively. Whereas the enzyme is specific in regard to the aromatic part of its substrate variations of the aliphatic rest are tolerated.
Purification and properties of the β‐glucosidase of a new strain of Candida molischiana able to work at low pH values: Possible use in the liberation of bound terpenols
Authors: Vasserot Yann , Chemardin Patrick , Arnaud Alain , Galzy Pierre
Published: February 2007

A yeast strain isolated in the laboratory was studied and classified as a Candida molischiana. The β‐glucosidase of this yeast strain was then purified. Its molecular weight, estimated by gel filtration, was 100,000. The enzyme consisted of only one subunit, identified after treatment with sodium dodecyl sulfate. Maximum activity was obtained at 55°C and pH 4 but the enzyme still possessed activity at pH 2.5. Active against different glucosides with β(1–2), β(1–3), β(1–4), β(1–6), and α(1–4) configurations it presented an α(1–6)‐arabinofuranosidase activity. The enzyme was competitively inhibited by glucose (Ki 9.5 mm). A glucosyltransferase activity appeared in the presence of ethanol. The enzyme was constitutive but its synthesis was repressed by glucose.
Purification and characterization of an inducible L‐lysine: 2‐oxoglutarate 6‐aminotransferase from Candida utilis
Authors: Hammer Thomas , Bode Rüdiger
Published: February 2007

L‐Lysine: 2‐oxoglutarate 6‐aminotransferase (EC 2.1.6.36) was purified 202‐fold from the yeast Candida utilis. The subunit Mr estimated by sodium dodecyl sulfate polyacrylamide gel electrophoresis was 40 kDa. The Mr of the native enzyme was estimated to be 83 kDa by gel filtration, suggesting a dimeric structure. The enzyme exhibits absorption maxima at 280, 340 and 420 nm, and binds 2 mol pyridoxal‐5‐phosphate/mol of the native enzyme. The aminotransferase has a maximum activity at pH 8.5 and at 4 °C. 2‐Oxoglutarate is the best amino acceptor with L‐lysine as amino donor. Lower activity is observed with oxaloacetate (38%), pyruvate (19%) and 2‐oxoadipate (7%) as acceptor or with L‐thialysine (13%) as donor. The Km values are 2.5 mM for L‐lysine, 3.8 mM for 2‐oxoglutarate and 0.015 mM for pyridoxal‐5‐phosphate. The enzyme activity is induced in cells grown in the presence of L‐lysine.
Studies on the root nodules of leguminous trees V. Production of indole acetic acid by a Bradyrhizobium sp. from the root nodules of a leguminous tree, Acacia auriculiformis A. CUNN
Authors: Bhattacharyya R. N. , Basu P. S.
Published: February 2007

The Bradyrhizobium sp., isolated from the root nodules of Acacia auriculiformis A. CUNN., a member of Mimosaceae, produced 17.0 μg/ml of indole acetic acid (IAA) from tryptophan in culture. The bacteria preferred D‐isomer over DL‐ or L‐isomer of tryptophan for IAA production. The IAA production could be promoted in culture medium up to 4.350% over control by supplementing the medium with fructose (0.5%), MnSO4 (0.1 μg/ml), glutamine (0.1%) and sodium dodecyl sulfate (SDS, 1.0 μg/ml). The possible relationship between the rhizobial IAA production and legume‐rhizobia symbiosis is discussed. The root nodules of leguminous plants are the result of rhizobial infection and are highly specialized structure which provide a special environment for the biological reduction of dinitrogen by the microsymbiont. Formerly nitrogen fixation was thought to be the only function of the nodules. Later hormone production by Rhizobium spp. drew great attention due to its involvement in the formation and growth of the nodules (KEFFORD et al. 1960, NUTMAN 1977). Rhizobium spp. are known to produce IAA from tryptophan in culture (DULLAART 1970, BHATTACHARYYA and BASU 1991). But most of the information is restricted to Rhizobium spp. isolated from the root nodules of the herbs of Fabaceae. This may be due to the immense economic importance of the pulses. Probably the first report on rhizobial IAA production of a tree legume was from Pongamia pinnata (SINHA and BASU 1981). Moreover, most of the leguminous plants so far studied belong to the family Fabaceae or Caesalpiniaceae. The report on rhizobial IAA production in a tree of the family Mimosaceae is very much scanty. Acacia auriculiformis is a leguminous tree of the neglected and unexplored family Mimosaceae. The mature nodule of A. auriculiformis contained 5.0 μg/g IAA (BHATTACHARYYA and BASU 1986/87), but any information on the ability of IAA production by its microsymbionts is lacking. But such information may throw some new light on the better understanding of the symbiosis of the root nodules. In addition, this neglected tree is also an useful sand binder and the seeds of this plant contain an important fatty acid (AMBASTA 1986). The purpose of this study was to throw some light on the IAA‐synthesizing capacity of the Bradyrhizobium sp. and to direct an effort to optimize the cultural requirement of the incubation medium for maximum IAA production by different supplements. This investigation yielded some interesting and tempting results which would be helpful to have an insight on the legume‐rhizobial symbiosis.
Flavonoids in seed coats ofMedicago arboreaandM. strasseri(Leguminosae): Ecophysiological aspects
Authors: Perez‐Garcia Felix , Ceresuela Jose L. , Gonzalez Aldo E. , Aguinagalde Itziar
Published: February 2007

Medicago arborea and M. strasseriare two leguminous species of great rusticity, valuables as ornamental and fodder plants. The high susceptibility to the fungal attack of their seeds limited those potential uses. Seven main flavonoids (Luteolin; Luteolin‐7‐glucoside; 7,3′,4′‐Trihydroxyflavone; 7,3′,4′‐Trihydroxyflavone 7‐glucoside; 7,4′‐Dihydroxyflavone; Quercetin‐3‐glucoside; Kaempferol‐3‐glucoside) were identified in the seed coats of both species. Their ecophysiological role is studied by bioassays: inhibition test of germination and radicle growth ofLactuca sativaand inhibition test of growth ofAlternaria alternataandPleospora herbarumfungus isolated from the seed coats.
Electrically induced protoplast fusion for ergosterol‐producing yeast strain improvement
Authors: Avram Dorina , Petcu Ileana , Radu Mihai , Dan Florica , Stan Rodica
Published: February 2007

Electrofusion was employed for hybrid construction in ergosterol‐producing yeast strains. Some fusion products proved to be hybrid with respect to ergosterol content and to remain stable over several generations.
pH‐Abhängigkeit der Cytochromc2(c)‐Reduktion und des Membranpotentials (Δ Ψ) in Modellsystemen und Chromatophoren von Purpurbakterien
Authors: Oleskin Alexander V. , Samullov Vitaly D.
Published: February 2007

Ubiquinol‐1 reduces cytochromecin solution at a rate which increases 10‐fold with an increase in pH by one unit within the range of 6.5 – 8.5. Light‐dependent generation of ΔΦ in proteoliposomes containingRhodospirillum rubrumreaction centers in the presence of ubiquinone‐1 and cytochromecis also stimulated with an increase in pH from 6.5 to 8.5. The ΔΦ generation inR. rubrumandRhodobacter sphaeroidesis described by a bell‐shaped pH‐dependence curve, the maximum responses being observed at pH 7.5–8.0. The dependence is retained with antimycin A (but not myxothiazol). The magnitude of the residual ΔΦ generation in the presence of myxothiazol or its combination with antimycin remains relatively constant in the pH range 6.5 to 9.5. Switching off the light, cytochromec2is reduced inRb. sphaeroideschromatophores, with the maximum rate at pH 7.3 – 7.6. The data obtained suggest that cytochromec2reduction by ubiquinol in purple bacteria is accomplished by cytochromebc1complex. In proteoliposomes and soluble systems, this process depends on a direct nonenzymatic reaction.
Metabolism of PAH by fungi and correlation with extracellular enzymatic activities
Authors: Sack Ute , Günther Thomas
Published: February 2007

The activity to metabolize the polycyclic aromatic hydrocarbons (PAH) phenanthrene, anthracene, pyrene, fluorene and fluoranthene by Trametes versicolor, Pleurotus ostreatus (white rot fungi), Laetiporus sulphureus, Daedaela quercina, Flamulina velutipes (brown rot fungi), Marasmiellus sp. (litter decaying fungus) and Penicillium sp. M 1 (isolated from a PAH contaminated soil sample) were compared. Screening methods for the presence of exoenzymes (peroxidases, polyphenoloxidases, “radical generating” enzymes) were evaluated for their use in screenings for fungi degrading PAH. Laetiporus sulphureus and Penicillium sp. M 1 cometabolize several PAH with rates comparable to white rot fungi. In most of the cases the patterns of extracellular peroxidases indicate the potential of fungi to degrade PAH.
Survey of mycoflora and mycotoxins of some dried fruits in Egypt
Authors: Zohri A. A. , Abdel‐Gawad Khayria M.
Published: February 2007

Fifty‐five species and two varieties appertaing to 23 genera were collected and identified from 4 samples of dried fig and 3 dried samples of each of apricot, plum and raisin. Forty‐nine species and two varieties belonging to 20 genera were isolated on 1% glucose‐CZAPEK's while 31 species and one variety belonging to 16 genera were isolated on 40% sucrose‐CZAPEK's agar medium at 28 ± 2 °C.Penicillium, Aspergillusandcladosporiumwere the common genera on the two types of media used.AlternariaandPleosporawere common on 1% glucose‐CZAPEK's agar only while the genus ofEurotiumwas isolated with high occurrence on 40% sucrose‐CZAPEK's agar. The common species on the two types of media used werePenicillium chrysogenum, Aspergillus nigerandcladosporium cladosporioides. On 1% glucose‐CZAPEK's agar.P. aurantiogriseum, A. fumigatus, A. flavus, Alternaria tenuissimaandPleospora herbarumwere isolated with high occurrence whileA. versicolor, A. wentii, Eurotium amstelodamiandE. chevalieriwere common on 40% sucrose‐CZAPEK's agar.

The different dried fruit samples were assayed for the natural occurrence of aflatoxins B1, B2, G1& G2, citrinin, ochratoxins, patulin, sterigmatocystin, diacetoxyscirpenol. T‐2 toxin and zearalenone by thin layer chromatographic analysis. Ochratoxin A was detected in all samples tested of apricot (50–110 μg/kg), fig (60–120 μg/kg) and plum (210–280μg/kg). The other mycotoxins under investigation were not detected. All samples examined of raisin proved to be mycotoxin free.
Temperature‐dependent expression of conjugation pili by IncM plasmid‐harbouring bacteria: Identification of plasmid‐encoded regulatory functions
Authors: Tietze Erhard , Tschäpe Helmut
Published: February 2007

A 1,3 kb DNA fragment of the IncM plasmid R446, if cloned in a multicopy plasmid, inhibits in trans the expression of conjugation pili by IncM plasmid‐harbouring host bacteria as indicated by their insensitivity to the IncM pilus‐dependent bacteriophage ϕM (Iml, insensitivity to ϕM‐mediated lysis). Determination of the nucleotide sequence of this DNA fragment, the introduction of deletions and the analysis of transposon insertions reveal two determinants, imlA and imlB, responsible for the Iml phenotype. A stretch of 80 bp of DNA containing imlA and about 450 bp of adjacent DNA comprising imlB, together, bring about inhibition of the typical expression of conjugation pili at 30 °C. The introduction of a transposable promoter probe and the construction of respective lacZ fusions indicate transcription of complementary strands in vivo overlapping in the region comprising imlA and imlB. Moreover, the expression of reporter genes discloses temperature‐dependent transcription of the imlA‐imlB‐region in one direction.

A particular subfragment of the 1.3 kb IncM plasmid‐derived DNA does not inhibit conjugation pilus expression at 30 °C but stimulates in trans the formation of pili at 42 °C to give rise to untypical sensitivity to ϕM at 42 °C in addition to 30 °C. Other subfragments reveal vital interferences with IncM plasmid‐harbouring host cells.

The putative nature of the cloned determinants interfering with the normal expression of IncM plasmid DNA is discussed.
Unspecific degradation of halogenated phenols by the soil fungus Penicillium frequentans Bi 7/2
Authors: Hofrichter Martin , Bublitz Friedemann , Fritsche Wolfgang
Published: February 2007

Resting phenol‐grown mycelia of the fungus Penicillium frequentans strain Bi 7/2 were shown to be capable of metabolizing various monohalogenated phenols as well as 3,4‐dichlorophenol. 2,4.dichlorophenol could be metabolized in the presence of phenol as cosubstrate. In the first degradation step the halogenated phenols were oxidized to the corresponding halocatechols. Halocatechols substituted in para‐position (4‐halocatechols) were further degraded under formation of 4‐carboxymethylenbut‐2‐en‐4‐olide. A partial dehalogenation took place splitting the ring system. 3‐Halocatechols were cleaved to 2‐halomuconic acids as dead end metabolites without a dehalogenation step. Dichlorophenols were only transformed to the corresponding catechols. In addition 3,5‐dichlorocatechol was O‐methylated to give two isomers of dichloroguaiacol. The halogenated catechols with the exception of 4‐fluorocatechol partly polymerized oxidatively in the culture fluid to form insoluble dark‐brown products. The degradation of halophenols are due to the action of unspecific intracellular enzymes responsible for phenol catabolism (phenol hydroxylase. catechol‐1,2‐dioxygenase, muconate cycloisomerase I).
Factors influencing β‐galactosidase activity ofAeromonas caviae
Authors: Karunakaran T. , Devi B. G.
Published: February 2007

Aeromonas caviae, often reported to be associated with diarrhoeal patients, elaborates several virulence factors as well as catabolic enzymes such as xylanase and β‐galactosidase. Studies on the kinetics of growth ofA. caviaeand synthesis of β‐galactosidase suggested that the activity was cell associated and reached a peak during the late logarithmic phase of growth. The optimum pH for β‐galactosidase activity was 7.0 and required Ca2+and glutathione for enhancement of its activity; IPTG also slightly improved the activity. Aerobic cultivation ofA. caviaein LB containing glucose, fructose, maltose and sucrose completely inhibited the activity possibly due to acetic acid production. Addition of 100 mM cAMP to the media containing glucose (0.25%, w/v) restored the relative activity by 8.8%; however, the final pH of the media remained acidic. Aerobic growth ofA. caviaewith other carbon sources did not affect β‐galactosidase activity, probably as there was no acid production and thereby the final pH of the media unaltered. Arabinose, xylose and galactose induced theA. caviaeβ‐galactosidase activity by several folds and lactose moderately enhanced its activity.
Cellulase activity and succession of fungi in soil amended with sodium chloride, organic matter and Ca‐superphosphate
Authors: Abdel‐Sater M. A.
Published: February 2007

The fungal population in soil amended with 2.5, 5 and 10% sodium chloride, sodium chloride with either 5% organic matter or 1% Ca‐superphosphate and incubated at 25 °C was studied after 2, 4 and 8 weeks. Sixty‐six species and 5 varieties belonging to 35 genera were isolated from the treated and untreated soils on glucose‐, cellulose‐ and 10% NaCl‐Czapek's agar at 25° or 45 °C. The total propagules, total counts ofAspergillusand counts 6f several species were significantly promoted with the low concentration of NaCl (2.5%) and decreased with the rise of NaCl levels. Also, the total counts of fungi were significantly flourished in soil amendment with sodium chloride when combined with organic matter or fertilizer after some storage periods. Several glucophilic, cellulose‐decomposing, xerophilic and thermophilic fungi were found to tolerate the previous conditions. The cellulolytic activities of most isolates tested were inhibited either by sodium chloride or combined with superphosphate and organic matter.
Ecological and physiological studies on thermophilic bacilli from sulfataric hot springs of central Italy
Authors: Canganella Francesco , Trovatelli Luigi Daniele
Published: February 2007

Hot springs located in a geothermal area of central Italy were investigated with respect to the total number of thermophilic microorganisms as well as to the presence of amylolytic and pullulolytic bacteria. A number of motile thermophilic spore‐forming bacteria were isolated from different sites. The aerobic organisms grew optimally at 60 −65°C on yeast extract‐trypticase and/or xylose‐starch supplemented mineral medium and spores were mostly observed on agar plates after prolonged incubation. According to the results based on phenotypic characterization, G + C% and lipid analyses all the aerobic isolates belong to the genus Bacillus and are characterized by an unusual G + C content ranging between 33.4 ‐ 38.8. A limited number of anaerobic organisms were also isolated and investigated for the presence of amylolytic and pullulolytic activity. According to physiological tests these isolates were identified as Clostridium thermohydrosulfuricum; when grown on starch, they produced thermostable α‐amylases, pullulanases and α‐glucosidases.
Thermally‐induced cell lysis in Escherichia coli K12
Authors: Membrillo‐Hernández Jorge , La Mora Alejandra Núñez‐De , Del Rio‐Albrechtsen Tania , Camacho‐Carranza Rafael , Gomez‐Eichelmann M. Carmen
Published: February 2007

Escherichia coli cells exposed to high temperatures exhibit a progressive loss of viability. We observed two mechanisms of cell death induced by lethal temperatures: with and without lysis. The number of cells lysed by heat decreased at later stages of the growth curve, when cells were pre‐treated at lower temperatures for 10 minutes and when cells were pre‐treated with novobiocin, nalidixic acid and cadmium chloride. Cell lysis was similar in wild type, rpoH, groE and dnaK mutant cells as well as in cells which overproduce heat shock proteins GroE or DnaK. Results using cells aligned for cell division and cells growing at 42°C, 45°C and 47°C suggest that cells near division are more sensitive to lysis and that a high concentration of heat‐shock proteins increases their resistance to lysis.
Simultaneous raw starch hydrolysis and ethanol fermentation by glucoamylase from Rhizoctonia solani and Saccharomyces cerevisiae
Authors: Singh Dalel , Dahiya Jagroop S. , Nigam Poonam
Published: February 2007

Crude glucoamylase preparation from Rhizoctonia solani was used to saccharify raw and cooked starch. Various concentrations of potato starch and wheat flour from 10–40%, w/v were used for mashing but 30% was found to be the optimal and economical. The saccharified mash yielded 5.89%, v/v ethanol in a simultaneous saccharification and fermentation process using a yeast strain Saccharomyces cerevisae (SC‐39) at 35°C for 4 days. Removal of inhibitory substances from the fermenting broth through dialysis caused considerable increase in ethanol production.
Isolation of porcine adenovirus as a candidate of 5th serotype
Authors: Kadoi K. , Inoue Y. , Ikeda T. , Kamata H. , Yukawa M. , Iwabuchi M. , Inaba Y.
Published: February 2007

A strain of cytopathic virus, named strain TG/K79, was isolated from the brain of a newborn piglet, pure Hampshire breed, which died shortly after birth. The physicochemical property of virus was considered to be that of the family Adenoviridae. A significant difference between our isolate and 4 reference porcine adenoviruses was demonstrated by cross‐seroneutralization test

Differences between TG/K79 and other porcine adenoviruses were also seen in electrophoretic patterns of viral DNA in agarose gel after digested by restiction endonucleases. Two SPF pigs, 2‐month‐old, experimentally infected via intranasal showed a fever and a hemorrhagic enteritis. A serological survey indicates that at least swine in the farm where the virus was isolated have been highly contaminated.
The fix Escherichia coli region contains four genes related to carnitine metabolism
Authors: Eichler Knut , Buchet Anne , Bourgis Fabienne , Kleber Hans‐Peter , Mandrand‐Berthelot Marie‐Andrée
Published: February 2007

Anaerobic carnitine metabolism in Escherichia coli was recently shown to involve six genes organized in the cai operon and located at the first minute on the chromosome. The DNA sequence lying at the 5′ end of the cai locus was further investigated. It contains four open reading frames organized as an operon. In vivo overexpression of this DNA region revealed four polypeptides with apparent molecular masses of 27, 33, 45 and 6 kDa. These proteins displayed significant amino acid sequence homologies with polypeptides encoded by the fixABCX operons from Azorhizobium caulinodans and Rhizobium meliloti. The four ORFs were thus named fixABCX. The first two gene products were also found to share a high degree of sequence similarity with the subunits β and α, respectively, of mammalian electron transfer flavoproteins, suggesting a role for these proteins in a redox reaction. A singly polycistronic 5 kb mRNA transcript was detected in Northern blots under anaerobic conditions in the presence of DL‐carnitine. Expression of a fixA‐lacZ transcriptional fusion was induced by L(‐)‐carnitine and crotonobetaine but not by D(+)‐carnitine, γ‐butyrobetaine, glycinebetaine and choline as found previously for the carnitine pathway. Similarly, the fix operon was repressed by glucose and nitrate. Moreover, expression of the fix operon was induced by the global regulatory proteins CRP and FNR and repressed by the histone‐like protein H‐NS. All these regulatory proteins have been shown also to control expression of carnitine enzymes. Results from Northern blots and lacZ fusion studies indicate a common regulation of expression of fix and cai operons, which implies a physiological linkage between these two loci.
Proteolytic activity of Aeromonas caviae
Authors: Karunakaran T. , Devi B. G.
Published: February 2007

Aeromonas strains produce a variety of virulence factors including proteases. Studies on the kinetics of growth of Aeromonas caviae NRRL B‐966 and its proteases suggest that the proteolytic activities are produced throughout the growth phase, with peak level occurring at stationary phase. A. caviae synthesize both intracellular and extracellular proteases with the latter account for major portion of the total activity. Optimum pH for the A. caviae proteolytic activity is at 7.0. A. caviae produces a thermoresistant protease, whose activity is dependent on Mg++ and Ca++ ions. Inhibition of proteolytic activity by phenyl methyl sulfonyl fluoride suggest the presence of a serine protease in A. caviae. Nitrogenous compounds enhance the proteolytic activity while carbohydrates tested in this study inhibit the activity.
Biological treatment of distillery waste for pollution‐remediation
Authors: Fitzgibbon F. J. , Nigam P. , Singh D. , Marchant R.
Published: February 2007

The biological treatment of spent wash from molasses distilleries was investigated. Analysis of raw spent wash showed it to be a recalcitrant waste, with a high COD of 85,170 mg/l and containing inhibitory phenolic compounds. Reverse phase thin layer chromatography identified gallic and vanillic acid present in spent wash. The fungi Geotrichum candidum, Coriolus versicolor, Phanerochaete chrysosporium and Mycelia sterilia were screened for their ability to decolourize spent wash and to reduce the COD level. A 10 day pretreatment with Geotrichum candidum at 30°C resulted in reducing the COD by 53.17% and total phenols by 47.82%, enabling other bioremediating organisms to grow. Coriolus versicolor immobilized in a packed‐bed reactor reduced the COD of spent wash by a further 50.3%, giving an overall reduction in COD of 77% to 15,780 mg/l. A small amount of decolourization was achieved (4.2%), although the spent wash was still coloured. Present studies are encouraging and indicate that it is possible to bioremediate spent wash using a multi‐stage treatment process involving an intial pretreatment step with Geotrichum candidum.
Cometabolic degradation of o‐cresol and 2,6‐dimethylphenol by Penicillium frequentans Bi 7/2
Authors: Hofrichter Martin , Bublitz Friedemann , Fritsche Wolfgang
Published: February 2007

o‐Cresol induced glucose‐grown resting mycelia of Penicillium frequentans Bi 7/2 (ATCC‐number: 96048) immediately oxidized o‐cresol and other phenols. After precultivation on glucose and phenol degradation started after a lag‐phase of 24 hours. Metabolites of o‐cresol metabolism were methylhydro‐quinone, methyl‐p‐benzoquinone, 2‐methyl‐5‐hydroxyhydroquinone and 2‐methyl‐5‐hydroxy‐p‐benzo‐quinone. The initial reaction is probably catalyzed by a NADPH dependent hydroxylase which is specific for o‐cresol. The metabolism of 2,6‐dimethylphenol (2,6‐xylenol) occurred via 2,6‐dimethylhydroqui‐none, 2,6‐dimethyl p‐benzoquinone, 2,6‐dimethyl‐3‐hydroxyhydroquinone, 2,6‐dimethyl‐3‐hydroxy‐p‐benzoquinone and 3‐methyl‐2‐hydroxybenzoic acid.
Isolation of dimeric nonactic acid from the nonactin‐producing Streptomyces spec. JA 5909‐1
Authors: Fleck Werner F. , Ritzau Michael , Heinze Stephan , Gräfe Udo
Published: February 2007

The formation of possible intermediates of nonactin (I) biosynthesis by Streptomyces spec. JA 5909‐1 was investigated. In addition to monomer nonactic acid (II), the dimeric nonactic acid (III) was isolated suggesting that III could be an intermediate of nonactin biosynthesis. The structure of III was settled by electrospray mass‐spectrometry and high‐field FT‐NMR methods. III displays no antibacterial and antifungal activities supporting the view that cation complex formation by nactin‐type antibiotics requires the entire macrotetrolide ring.
Enhanced excretion of intermediates of aromatic amino acid catabolism during chlorophenol degradation due to nutrient limitation in the yeast Candida maltosa
Authors: Hammer Elke , Kneifel Helmut , Hofmann Klaus , Schauer Frieder
Published: February 2007

Incubation of phenol‐induced cells of the yeast Candida maltosa SBUG 700 with mono‐ and dichlorophenols resulted in the formation of metabolites of the substrates and of further metabolites not related to the degradation pathway of the substrates. These additional compounds, identified as 4‐hydroxyphenylacetic acid (4‐HPA), phenylacetic acid (PA), indolylacetic acid (IA) and indolylethanol (IE) by means of HPLC and GC/MS, were not excreted in incubation experiments with glucose.

The excretion of these metabolites of aromatic amino acid metabolism is not caused by toxic effects of the phenol derivatives, but seems to be a result of carbon and nitrogen starvation of yeast cells.
Unusual resistance and acquired tolerance to cadmium chloride in Enterococcus faecalis
Authors: Paplace Jean‐Marie , Boutibonnes Philippe , Auffray Yanick
Published: February 2007

Enterococcus faecalis exhibits an extremely high natural resistance to cadmium which can be even raised by a conditioning treatment at a lower cadmium concentration as well as by a previous exposure to a sublethal temperature. By contrast, thermotolerance is not significantly induced by previous exposure to low cadmium concentration. The synthesis of several proteins is markedly enhanced by a low concentration of the chemical agent.
Analysis of the PHA granule‐associated proteins GA20 .and GA11 in Methylobacterium extorquens and Methylobacterium rhodesianum
Authors: Föllner Christina G. , Madkour Mohamed , Mayer Frank , Babel Wolfgang , Steinbüchel Alexander
Published: February 2007

Electrophoretic analysis of the proteins bound to poly(3‐hydroxybutyric acid), PHB‐, granules in Methylobacterium extorquens, M. rhodesianum as well as the PHB‐leaky mutants Mu 1 and Mu 11, which were isolated from the latter, resulted in two dominant low‐molecular weight proteins, which were referred to as GA 11 and GA20. After purification of these proteins antibodies against the GA11 and GA20 protein of M. extorquens were obtained. Both proteins bound to the surface of PHB granules as revealed by immunoelectron microscopy of whole cells of M. extorquens and M. rhodesianum. With cells of the PHB‐leaky mutants Mu 1 and Mu 11 no specific labeling was observed. The N‐terminal amino acid sequences of the GA11 and the GA20 protein were determined. We found significant homologies between the sequences of the investigated strains. The use of oligonucleotide probes based on the N‐terminal sequences of the GA20 protein from M. rhodesianum to identify the corresponding structural genes in various genomic libraries failed.
Degradation of dimeric lignin model compounds by aerobic bacteria isolated from the hindgut of xylophagous termites
Authors: Kuhnigk Thomas , König Helmut
Published: February 2007

The capability of the intestinal flora from the gut of xylophagous termites of degrading lignin model compounds was investigated. Different dimeric lignin model compounds‐degrading bacteria were obtained from the hindgut flora of Mastotermes darwiniensis FROGGATT, Reticulitermes santonensis FEYTAUD, Nasutitermes nigriceps HALDEMAN and Zootermopsis angusticollis HAGEN. In the presence of oxygen dimeric model compounds were degraded by all isolates. This indicates that the hindgut flora of termites is basically able to produce substrate for their host from aromatic extractives of wood.
Degradation of phenanthrene and pyrene by Nematoloma frowardii
Authors: Sack Ute , Hofrichter Martin , Fritsche Wolfgang
Published: February 2007

The white‐rot fungus Nematoloma frowardii was examined for the ability to degrade [ring U‐14C]‐phenanthrene and [4,5,9,10‐14C]pyrene in liquid and solid (straw) cultures in a period of 63 days. 3.2% phenanthrene and 8.6% pyrene were mineralized to 14CO2 in liquid cultures, respectively. A considerable higher mineralization of 11.2% (phenanthrene) and 46.5% (pyrene) was detected in straw cultures. Metabolites were identified by their UV absorption spectra. N. frowardii transformed phenanthrene to phenanthrene 9,10‐dihydrodiol. Pyrene 4,5‐dihydrodiol was identified as major metabolite in pyrene degradation.
Intracellular proteolytic activity of the haloalkaliphilic archaeon Natronococcus occultus. Effect of starvation
Authors: Seitz Karina Herrera , Studdert Claudia , Sanchez Jorge , de Castro Rosana
Published: February 2007

Intracellular proteolytic activity was detected in the haloalkaliphilic archaeon Natronococcus occultus during the stationary phase of cultures grown in complete medium and during carbon and nitrogen starvation. Puromycin prevented the occurrence of proteolytic activity in starved cells, suggesting that de novo synthesis of proteolytic enzymes might be required for protein degradation during starvation. Intracellular proteolytic activity degraded casein and gelatin. It had a temperature optimum of 60 °C in 2 M NaCl and depended on high salt concentration (NaCl or KCl) for activity and stability. Gelatin zymography of cell extracts from stationary phase or starved cells showed a complex pattern of proteolytic bands ranging from ∼ 20 to 120 kDa. All these proteolytic bands were inhibited by PMSF1) and chymostatin. However, they showed differences in stability to temperature and salt concentration.
The start of the rains in West Africa
Authors: Stern R. D. , Dennett M. D. , Garbutt D. J.
Published: February 2007

The start of the rains is defined as the first occurrence of a specified amount of rain within two successive days. The probability distribution of the date of the start of the rains is derived from the rainfall models of Stern (1980a). The probabilities of occurrence of dry spells are used to define an earliest practical starting date. Results are presented for eleven stations on a N‐S transect in West Africa. The variation in starting date with latitude is described. Advantages of the model approach over conventional analyses are discussed.
Correlations between the tropical atlantic trade winds and precipitation in northeastern Brazil
Authors: Chung James C.
Published: February 2007

Surface wind and sea surface temperature data for the tropical Atlantic Ocean for the period 1911‐1972 are analysed in relation to the precipitation at Quixeramobim, Ceará in northeastern (NE) Brazil. Stratified correlations between the March‐April‐May Quixeramobim rainfall and the December, January, February, and March values of SST, and u‐ and v‐components of surface wind are presented for the tropical Atlantic. The implications of the correlations are that the months preceding an abnormally dry rainy season in NE Brazil are characterized by a strengthened South Atlantic trade flow and a North Atlantic circulation slightly weaker than normal. Cold SST anomalies are found in the South Atlantic and warm anomalies in the North Atlantic, suggesting a wind‐induced change in surface mixing or in evaporation from the surface. The divergence over the South Atlantic is seen to be stronger and more extensive preceding a dry season, and the equatorial convergence appears to be compressed northward and also strengthened. This northward compression is concluded to be responsible for the lack of rainfall in Ceará.
On the intra‐annual variation in rainfall over the sub‐continent of southern Africa
Authors: Dyer T. G. J.
Published: February 2007

The variation in intra‐annual variance in rainfall over Southern Africa is examined for evidence to support the contention that it has undergone a systematic upward change over the period 1921‐1974. A principal components analysis on the data shows that the time series of intra‐annual variances may be represented by four components. Although each of the four principal component time series possesses an oscillation in the region of the biennial wave, there is little evidence to suggest that the within‐year variation in rainfall is undergoing any type of upward trend.
A study of the influence of surface albedo on July circulation in semi‐arid regions using the glas GCM
Authors: Sud Y. C. , Fennessy M.
Published: February 2007

A numerical simulation study of the influence of surface albedo on July circulation in semi‐arid regions, using the general circulation model (GCM) of the Goddard Laboratory of Atmospheric Sciences (GLAS) is presented. The results are based on two 47‐day integrations. In the first integration, called the control run, the surface albedo was normally prescribed, whereas in the second integration, called the anomaly run, the surface albedo was modified in four regions: the Sahel in Africa, the western Great Plains in the United States, the Thar Desert border in the Indian subcontinent, and northeast Brazil in South America. This experiment is similar to that of Charneyet al.(1977); however, it was performed with the GLAS model with vastly different boundary forcings and several changes in the physical parameterizations.

Each run was started from observed initial conditions for 15 June 1979, based on NMC analysis. An analysis of the two simulations shows that in the Sahel, and the Thar Desert border regions the current results again show reduced precipitation with increased surface albedo in accordance with Charneyet al.(1977) and Charney (1975). The semi‐arid northeast Brazil region, which had a winter circulation, also conforms with Charney's (1975) hypothesis. However, the Great Plains region was an exception. There the total precipitation in two simulations was unchanged, as was the total cloudiness. In this region, the convective precipitation was reduced somewhat, while the large‐scale precipitation compensated this decrease by approximately the same amount. The lack of albedo impact on precipitation in the Great Plains region could be due to the influence of the Rocky Mountains in generating variations in the large‐scale flow.

The purpose of repeating Charney's albedo experiment was to test the sensitivity of his earlier results with the current GLAS GCM which has substantially modified physical parameterizations, particularly the planetary boundary layer (PBL), crucially important for such impact studies. Taking into account that both the GCM and the initial conditions of the atmosphere were different, it is worth noting that this experiment still provides support for Charney's hypothesis (1975) regarding the influence of surface albedo on mean‐monthly climatology in the subtropical desert margin regions.

Another important influence noted was the variability of mean monthly simulation in areas far away from the albedo anomaly regions. Because the differences occur in regions of high observed climatological variability, it is necessary to separate the contribution of albedo anomalies as opposed to the model variability. The influence of surface albedo changes to produce large changes in the mean montly circulation elsewhere is very intriguing and needs further investigation.
Protection from cold stress in a Eucalyptus shelterwood
Authors: Nunez M. , Sander D.
Published: February 2007

Nocturnal measurements of air, temperature and longwave radiation were taken in a Eucalyptus delegatensis shelterwood and in a clearfelled control site. On average the shelterwood exhibited temperatures between 1°C and 2°C warmer. Longwave radiation correlated well with percentage sky view as determined from fish eye lens photographs. The shelterwood seems to decrease the radiation loss by an average figure of 21 per cent on a cloudless night. The Brunt cooling theory is used to relate the air temperature and radiation figures.
Zonal index and circulation change in the north Atlantic area, 1873–1972
Authors: Makrogiannis T. J. , Bloutsos A. A. , Giles B. D.
Published: February 2007

Monthly and annual values are calculated of a zonal index based on surface pressure at 35°N and 55°N between 60°W and 10°W. The period under study, 1873‐1972, is divided into three sub‐periods which approximate with three epochs proposed by Lamb (1972). A comparison of our indices with Lamb's results is followed by a discussion of our monthly index, and the rarity of easterly flow in the 100‐year period is noted. The results are subjected to a trend and a power spectrum analysis and the latter indicates a number of periodicities some of which are not easily explicable.
Associations among the tropical pacific wind and sea surface temperature fields and higher latitude circulation
Authors: Harnack Robert P. , Lanzante John R. , Harnack Jeremi
Published: February 2007

An empirical study was conducted examining associations between seasonal trade wind and sea surface temperature (SST) fields in the eastern half of the tropical Pacific Ocean for the period 1949‐1979. In addition, the tropical fields were statistically related to the extratropical circulation of the Northern Hemisphere (i.e. 700 mb heights). This study differs from most prior studies in that the trade wind field was examined primarily in terms of the horizontal trade wind divergence and seasonally stratified lag relationships were computed.

Seasonally stratified autocorrelations of empirical orthogonal function (EOF) amplitudes (out to four seasons) indicated significant persistence of EOF1 of SST and divergence until spring‐summer for any initial season; accordingly, spring and summer (summer and autumn) EOF1 for SST (divergence) exhibited the greatest persistence. For divergence some tendency for a reversal of sign was seen from the autumn, winter, or spring seasons to the following autumn, which may imply negative air‐sea feedback mechanisms operating.

Seasonally stratified cross correlations betwen the first EOF for SST and divergence indicated a significant contemporaneous relationship. When divergence leads SST, the relationship is significant at short lags (1‐3 seasons) until spring as a target season is reached. The same is true when SST leads divergence except that a significant relationship returns with opposite sign in the subsequent summer and auiumn. Winter SST and divergence, in particular, are well correlated with prior values of the other parameter.

When the tropical parameters were related to the extratropical circulation through correlation with gridded 700 mb heights, significant patterns were found only when winter 700 mb heights were the target parameter (i.e. tropical parameter leading winter 700 mb heights). Summer through winter tropical SST and divergence (EOF1) displays a good association with subsequent winter extratropical circulation in the form of an expanded/contracted circumpolar vortex. The relationship between trade wind divergence and subsequent winter circulation is significant using the prior winter (4 season lag), vanishes during spring, and returns with the opposite sign for summer through winter (lags 0‐2). Using either SST or divergence, the observed relationships are stronger at lags 1 and 2 than at lag 0.
Fluctuations in northeast monsoon rainfall of Tamil Nadu
Authors: Dhar O. N. , Rakhecha P. R. , Kulkarni A. K.
Published: February 2007

The average rainfall series of Tamil Nadu for the northeast monsoon months of October to December and the season as a whole were analysed for trends, periodicities and variability using standard statistical methods. The trend analysis showed that there are no long‐term trends of increasing or decreasing rainfall in the individual months or the season as a whole. The power spectrum analysis of rainfall series showed peaks at frequencies corresponding to the time periods of 2 to 2–44 years and 3–66 to 4–40 years.
The use of average annual rainfall to derive estimates of orographic enhancement of frontal rain over England and Wales for different wind directions
Authors: Hill Frank F.
Published: February 2007

A field of average annual enhancement, defined as the mean rainfall rate al inland sites minus the mean rate over the coast, has been derived for England and Wales. Past cases of frontal rain associated with low‐level winds from the SW quadrant were analysed so as to determine the typical distribution and intensity of orographic enhancement. It is shown that these results are sensitive to wind speed and, in particular, direction. Comparison of these results suggest relationships between orographic enhancement and average annual enhancement which are used to produce estimates of the distribution of enhancement which may occur with low‐level winds from other directions. These enhancement fields can he combined with radar observations of rain over the sea to produce short‐period forecasts of rainfall intensity when it moves overland.
Distinguishing signal and noise in climatological spectra
Authors: Gray B. M.
Published: February 2007

A simple statistical test is proposed for matching the peaks occurring in two spectra, and an application to rainfall data is described. By comparing the spectra of related variables, small peaks in the rainfall spectra are shown lo contain information. However regularities in the occurrence of minima and maxima in climatological spectra can be explained by non‐linearities in the noise portion of the input data.
The dynamic climatology of the beaufort to Laptev sea sector of the polar basin for the summers of 1975 and 1976
Authors: Ledrew Ellsworth F.
Published: February 2007

For the summer months of 1975 and 1976, the total vertical velocity at 850 millibars is computed from a diagnostic atmospheric model as an index of synoptic activity in the Beaufort to Laptev Sea sector of the Polar Basin. The objective is to identify the major modes of synoptic activity in the region and to determine the major formative mechanisms for significant synoptic vortices. This will lead to an understanding of the dynamics involved in the evolution and maintenance of synoptic patterns in the Arctic.

Cluster analysis is used to stratify the 850 mb geopotential height data into synoptic modes. The mean 850 mb total vertical velocity field for each cluster is calculated, and indices related to each of the formative mechanisms are related to these individual fields through regression analysis and pattern comparison. These mechanisms are: vorticity and thickness advection, diabatic effects of latent heat release and surface heating, and frictional and orographic influences at the surface. Explanations for the dynamics of the major regional vortices are discussed.
On the correlation between monthly and annual mean temperatures
Authors: Sawyer J. S.
Published: February 2007

Except for winter months, correlation between monthly and annual mean temperatures in Central England is, higher than would be expected if all monthly mean temperatures were uncorrelated. The correlation is increased if decadal means are taken, indicating an association of monthly temperature with some factor persisting over a decade or more. This correlation is not reduced if the association of the monthly mean temperature with the monthly mean pressure field is removed. It is suggested that there must be important factors causing climatic fluctuations in England which are not closely associated with changes in the frequency of synoptic types and which do not operate in winter.
African mean wind changes between sahelian wet and dry periods
Authors: Newell Reginald E. , Kidson John W.
Published: February 2007

African free air wind velocity data for wet and dry periods in the Sahel have been analysed objectively by the Cressman scheme and show that the lower troposphere easterly jet over west Africa is stronger in the dry period whereas the analogous easterly jet to the south of the equator exhibits greater vertical shear in the wet period. Two possible explanations, based on modulations of the meridional temperature gradients across the jet, are offered.
A method for correcting non‐linear chart recorder output
Authors: Smithson P. A. , Pickering W. M.
Published: February 2007

Non‐linear chart traces can be digitized if the output is corrected by a mathematical function. A procedure is described which is advantageous if the recorder output may be regarded as symmetric about the mid‐point of the chart.
A criterion for defining transitional zones between humid continental and mediterranean climates in the region of Greece
Authors: Kotinis‐Zambakas S. R. , Angouridakis Vi. E. , Zambakas J. D.
Published: February 2007

The annual march of the mean monthly number of thunderstorm days at a station shows certain characteristics, depending on the prevailing climate. For example, the main maxima in continental and marine climates occur in summer and in autumn to winter, respectively. A gradation of such an annual march of thunderstorm activity is successfully used in delineating transitional climatic zones in Greece, and it might also be applied to other regions of the earth.
Summer energy budget simulation for A latitudinal transect along the east coast of the Americas
Authors: Terjung Werner H. , O'Rourke Patricia A.
Published: February 2007

The physically‐based model BUDGET combined a solar radiation transmission model and a steady state slope energy budget model. Climatic observations, averaged for 10‐degree latitude bands, were used as input in order to systematically examine the changing energy budget components (net radiation, conduction, sensible, and latent heat flux) occurring at the various slope angles (0 to 90°) and directions (south‐, west‐, and north‐facing). Two contrasting landscapes were examined (barren and grassy) along a latitudinal transect of the east coast of the Americas (northern hemisphere). The response of energy budget components was systematic and orderly on a latitudinal basis. However, a great diversity among energy budgets between different slopes and their orientation at a particular latitude was characteristic and more pronounced in the higher latitudes. These findings were assumed to be general enough to encompass most of the possible contrasts encountered in a real‐world north‐south transect.