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PubMed2005

The use of the aquatic moss Fontinalis antipyretica L. ex Hedw. as a bioindicator for heavy metals: 3. Cd2+ accumulation capacities and biochemical stress response of two Fontinalis species.

We studied heavy metal stress responses of two Fontinalis species, F. antipyretica and F. dalecarlica, collected from two habitats in Germany and Canada. The capacities of the two species for extracellular adsorption (biosorption) and intracellular uptake (bioaccumulation) of Cadmium (Cd2+) were investigated in the laboratory. Time-dependent Cd2+ adsorption by cell wall and intracellular uptake differed significantly between the two species. These differences were related to the number of Cd2+ binding sites, resulting from differences in leaflet surface and cell wall composition. Glutathione (GSH) levels in response to Cd2+ exposure were monitored over a 10-day period. GSH synthesis differed significantly between the two species. Both Fontinalis species appear to be suitable for heavy metal biomonitoring in aquatic habitats.

Adsorption↗
PubMed2001

Simulation of motor-driven cochlear outer hair cell electromotility.

We propose a three-dimensional (3D) model to simulate outer hair cell electromotility. In our model, the major components of the composite cell wall are explicitly represented. We simulate the activity of the particles/motor complexes in the plasma membrane by generating active strains inside them and compute the overall response of the cell. We also consider the constrained wall and compute the generated active force. We estimate the parameters of our model by matching the predicted longitudinal and circumferential electromotile strains with those observed in the microchamber experiment. In addition, we match the earlier estimated values of the active force and cell wall stiffness. The computed electromotile strains in the plasma membrane and other components of the wall are in agreement with experimental observations in trypsinized cells and in nonmotile cells transfected with Prestin. We discover several features of the 3D mechanism of outer hair cell electromotilty. Because of the constraints under which the motors operate, the motor-related strains have to be 2-3 times larger than the observable strains. The motor density has a strong effect on the electromotile strain. Such effect on the active force is significantly lower because of the interplay between the active and passive properties of the cell wall.

Cell Membrane↗
PubMed2003

Structural and biological characterization of a crotapotin isoform isolated from Crotalus durissus cascavella venom.

Envenoming by Crotalus durissus subspecies leads to coagulation disorders, myotoxicity, neurotoxicity and acute renal failure. The most serious systemic alteration and primary cause of death after snakebite is acute renal failure. In this work, we isolated crotapotin, an acid component (Crtp) of crotoxin from Crotalus durissus cascavella venom and we investigated its bactericidal and pro-inflammatory activities as well as its renal effects in rat isolated perfused kidneys. Crtp was bactericidal to the Gram-negative species Xanthomonas axonopodis pv. passiflorae, but was less effective against the Gram-positive Claribacteri ssp, probably because of differences in the cell wall composition. Crtp showed a high amino acid sequence homology with other Crtps described in the literature (around of 90%) and its A and B chains had high conserved regions corresponding to the calcium-binding loop, catalytic site and helix 3 of PLA2. The Crtp showed moderate pro-inflammatory activity and increased significantly the inflammation evoked by PLA2 when co-injected or co-incubated with PLA2. The renal parameters evaluated included the perfusion pressure (PP), renal vascular resistance (RVR), urinary flow (UF), glomerular filtration rate (GFR) and percent of sodium tubular transport (%TNa+). Crotapotin (5 microg/ml) significantly increased the PP and RVR, whereas the GFR, UF and %TNa+ were unaffected. These results suggest that crotoxin is the main venom component responsible for nephrotoxicity and crotapotin contributes little to this phenomenom. The biological and bactericidal actions of Crtp also suggest that this protein may have functions other than simply acting as a chaperone for PLA2.

Actinomycetales↗
PubMed2000

Comparative characterization of two serine endopeptidases from Nocardiopsis sp. NCIM 5124.

A protease-producing, crude oil degrading marine isolate was identified as Nocardiopsis sp. on the basis of the morphology, cell wall composition, mycolic acid analysis and DNA base composition. The Nocardiopsis produces two extracellular proteases, both of which are alkaline serine endopeptidases. Protease I was purified to homogeneity by chromatography on CM-Sephadex at pH 5.0 and pH 9.0. Protease II was purified using DEAE-cellulose, Sephadex G-50, phenyl-Sepharose and hydroxyapatite chromatography. Protease I and II had almost similar M(r) of 21 kDa (Protease I) and 23 kDa (Protease II), pI of 8.3 and 7.0 respectively with pH and temperature optima for activity between 10.0 and 11.0 and about 60 degrees C. Specific activities were 152 and 14 U/mg respectively on casein. However, Protease I was antigenically unrelated to Protease II. Both proteases were endopeptidases and required extended substrate binding for catalysis. Both proteases had collagenolytic and fibrinolytic activity but only Protease I had elastinolytic activity. The proteases were chymotrypsin-like with respect to their amino acid compositions and N-terminal sequences.

Actinomycetales↗
PubMed2001

Studies on carboxymethyl cellulase produced by an alkalothermophilic actinomycete.

A novel alkalothermophilic actinomycete having optimum growth at pH 9 and 50 degrees C was isolated from self-heating compost from the Barabanki district of Uttar Pradesh, India. Based on its morphology, susceptibility of spores to heat and novobiocin, guaninecytosine content of chromosomal DNA and cell wall composition, the organism was classified under Thermomonospora. The alkalothermophilic actinomycete produced 23 IU/ml carboxymethyl cellulase (CMCase). The CMCase was purified by fractional ammonium sulphate precipitation followed by cellulose affinity chromatography and Sephacryl S-200 gel filtration. The CMCase had a molecular weight of 38 KD and pI of 4.1. The enzyme exhibited optimum activity at pH 5 and temperature 50 degrees C. The CMCase showed pH stability in the range 7-10. The enzyme retained 100% activity at 50 degrees C for 72 h and had half-lives of 7 and 3 h at 60 degrees C and 70 degrees C, respectively. The CMCase was stable in the presence of commercial detergents such as Ariel, Henko and Surf Excel, indicating its potential as an additive to laundry detergents.

Actinomycetales↗
PubMed2006

Isolation and antifungal and antioomycete activities of staurosporine from Streptomyces roseoflavus strain LS-A24.

The actinomycete strain LS-A24 active against some plant fungal and oomycete pathogens was isolated from a soil sample of the Sunghwan Lake in Korea. The cell wall composition and spore shape of strain LS-A24 were LL-diaminopimelic acid and spiral type, respectively. On the basis of the physiological and biochemical characteristics and 16S ribosomal DNA sequence analysis, strain LS-A24 was identical to Streptomyces roseoflavus. An antifungal and antioomycete antibiotic was isolated from LS-A24 using various chromatographic procedures. The molecular formular of the antibiotic was determined to be C(28)H(26)N(4)O(3), and on the basis of the NMR data, the antibiotic was confirmed to be staurosporine, 2,3,10,11,12,13-hexahydro-10R-methoxy-9S-methyl-11R-methylamino-9S,13R-epoxy-1H,9H-diindolo[1,2,3-gh:3',2',1'-lm]pyrrolo[3,4-j][1,7]benzodiazonin-1-one. Staurosporine completely inhibited the mycelial growth of Colletotrichum orbiculare, Phytophthora capsici, Rhizoctonia solani, Botrytis cinerea, and Cladosporium cucumerinum with minimum inhibitory concentration (MIC) values of 1-50 microg/mL for MICs. Staurosporine also was active against Saccharomyces cerevisiae, Bacillus subtilis ssp. subtilis, and Xanthomonas vesicatoria. Staurosporine and the commercial fungicide metalaxyl inhibited the development of Phytophthora blight on pepper plants. However, the control efficacy of staurosporine against the Phytophthora disease was somewhat less than that of metalaxyl. This is the first study to isolate staurosporine from S. roseoflavus and demonstrate its in vitro and in vivo antioomycete activity against P. capsici.

Fungicides, Industrial↗
PubMed2004

Histopathology of Sclerotinia sclerotiorum attack on flower parts of Helianthus annuus heads in tolerant and susceptible varieties.

Sunflower head rot is a major disease caused by Sclerotinia sclerotiorum. Sunflower varieties which are tolerant to the fungus have been developed. The changes occurring in flower parts at different times after inoculation with pathogen ascospores were studied for two sunflower varieties (tolerant HA 302 and susceptible HA 89). In variety HA 302 there was cell collapse, changes in cell wall composition, and an increase in phenolic compounds in the tissues of corolla and style, which prevented the pathogen from advancing. This response was weaker in susceptible variety HA 89, and occurred only in the style, so did not stop the pathogen from developing and reaching the ovary. Phenolic compounds were found in HA 302 corolla and style tissues only when the pathogen was present, constituted an induced response that prevented further development of the fungus. Principal component analysis (PCA) showed that at the beginning of the infection there was no difference in behavior between the two varieties. The difference arose during the final observation times, when in variety HA 89, the pathogen colonized ovary, style and base of filaments and produced noticeable colonization of the corolla.

Argentina↗
PubMed2000

Single point mutations in either gene encoding the subunits of the heterooctameric yeast phosphofructokinase abolish allosteric inhibition by ATP.

Yeast phosphofructokinase is a heterooctameric enzyme subject to a complex allosteric regulation. A mutation in the PFK1 gene, encoding the larger -subunits, rendering the enzyme insensitive to allosteric inhibition by ATP was found to be caused by an exchange of proline 728 for a leucine residue. By in vitro mutagenesis, we introduced this mutation in either PFK1 or PFK2 and found that the exchange in either subunit drastically reduced the sensitivity of the holoenzyme to ATP inhibition. This was accompanied by a lack of allosteric activation by AMP, fructose 2,6-bisphosphate, or ammonium and an increased resistance to heat inactivation. Yeast cells carrying either one mutation or both in conjunction did not display a strong phenotype when grown on fermentable carbon sources and did not show any significant changes in intermediary metabolites. Growth on non-fermentable carbon sources was clearly impaired. The strain carrying both mutant alleles was more sensitive to Congo Red than the wild-type strain or the single mutants indicating differences in cell wall composition. In addition, we found single pfk null mutants to be less viable than wild type at different storage temperatures and a pfk2 null mutant to be temperature-sensitive for growth at 37 degrees C. The latter mutant was shown to be respiration-dependent for growth on glucose.

Adenosine Triphosphate↗
PubMed2004

Light, conventional and environmental scanning electron microscopy of the trichomes of Cucurbita pepo subsp. pepo var. styriaca and histochemistry of glandular secretory products.

BACKGROUND AND AIMS: In the present study, the differences between glandular and non-glandular trichomes, the secretory process and the method of secretion were studied. Previous studies on leaves of Styrian oil pumpkin (Cucurbia pepo var. styriaca) plants have shown that four morphologically and ontogenetically independent glandular and non-glandular trichome types and one bristle hair type can be distinguished. The four types of trichomes can be categorized into three glandular trichome types: type I, a short-stalked trichome with four head cells including a 'middle-cell', two stalk cells and one basal cell; type II, a long-stalked trichome with two head cells, a 'neck-cell' region and a long stalk area; type IV, a 'stipitate-capitate' trichome with a mesophyll cell basement, a short stalk and a multicellular head; type III, a non-glandular 'columnar-digit' trichome, which consists of two head cells continuous with three-celled stalk, and the basal cell. METHODS: The histochemical studies (the main classes of metabolite in secreted material of glandular trichomes) were conducted in fresh and fixed hand sections, using the following tests: Sudan black B, Nile blue A, osmium tetroxide, neutral red, Naturstoffreagent A, FSA (fuchsin-safranin-astra blue), NADI (naphthol + dimethylparaphenylenediamine) and ruthenium red. Each suggested differences in the intercalations during the ontogenetical development of each trichome during the development stage. KEY RESULTS: The histochemical reactions revealed the main components of the materials secreted by all types of trichomes, which include lipids, flavones and terpenes and the different cell wall compositions. Glandular secretions were observed during environmental scanning electron microscopy (ESEM) and the trichomes compared with those seen by conventional scanning electron microscopy (CSEM). CONCLUSIONS: Scanning electron microscopy and histochemical analysis demonstrated that each of the trichomes studied produced and released secretory products in a characteristic way.

Cucurbita↗
PubMed2005

Genes encoding ADP-ribosylation factors in Arabidopsis thaliana L. Heyn.; genome analysis and antisense suppression.

Vesicle trafficking delivers proteins to intracellular and extracellular compartments, cellulose synthase to the plasma membrane, and non-cellulosic polysaccharides to the cell wall. The Arabidopsis genome potentially encodes 19 proteins with sequence similarities to ARFs (ADP-ribosylation factors) and its relatives such as ARLs (ARF-like proteins). ARFs are essential for vesicle coating and uncoating in all eukaryotic cells, while ARLs play more diverse roles. Nine proteins, six of them highly similar, are possible ARFs, three are putative ARL orthologues and the remainder were designated ARF-related proteins. The functions of the six highly similar, putative ARFs in whole plant development were probed by suppressing their expression with antisense. Antisense plants were severely stunted because cell production rate and final cell size were both reduced. Changed time-to-flowering, apical dominance, and fertility may reflect alterations to hormonal and other signalling pathways with which ARFs may interact. No gross changes in targeting or compartmentalization were seen in antisense plants containing GFP targeted to the ER and Golgi and changes in cell wall composition were limited to increases in some non-cellulosic polysaccharides and a relatively small decrease in cellulose. The reasons why these effects are less drastic than the effects on endomembranes and wall composition that are seen in short-term experiments with brefeldin A and with dominant negative ARF mutants are discussed.

ADP-Ribosylation Factors↗
PubMed2005

Calorie restriction protects against age-related rat aorta sclerosis.

Many theories have been advanced to account for the ageing process, among which the free radical theory deserves much attention. Numerous studies have also shown an association between tissue fibrosis and oxidative stress. Of note, fibrosis may be considered a significant index of tissue ageing. Calorie restriction (CR) has been demonstrated to maintain many physiological processes in a youthful state until a very advanced age. However the anti-ageing mechanisms of CR are still not fully understood. We thus evaluated the effect of CR on oxidative damage and its relationship with fibrosis during ageing. We found a significant increase of both oxidative stress and fibrosis parameters in the aortae from aged vs. young rats. CR reversed both phenomena. CR also protected against the age-associated increase of Jun-N-terminal kinase and p-38 activities, involved in TGFbeta1 expression and signaling. On the contrary, extracellular regulated kinases did not show any age-related change. CR similarly reversed the age-related increase of AP-1 DNA binding activity and the AP-1-dependent increase of vimentin gene expression. In parallel, CR reversed the age-related morphological alterations of the aorta wall cell composition. These data further support the relationship between oxidative stress and fibrosis in different diseases and during ageing. The protection exerted by CR against fibrosclerosis might be due to a decrease of oxidative stress, with consequent decreased MAPK activity and down-regulation of AP-1 activation and of TGFbeta1 expression and signaling.

Actins↗
PubMedDate not supplied

Interactions of vancomycin resistant enterococci with biomaterial surfaces.

Enterococci are a frequent cause of nosocomial infections and are often found adherent to indwelling catheters. Concern about such device associated infections has increased with the appearance of vancomycin resistant (VR) enterococci. However, the possible influence of vancomycin resistance in the pathogenesis of biomaterial centered infection has not yet been assessed. Using polyethylene terephthalate (PET) disks as model surfaces, the authors evaluated possible differences in the adherence and persistence of vancomycin sensitive (VS) and VR strains of Enterococcus faecium and Enterococcus faecalis on biomaterial surfaces in vitro and in vivo. The results indicate that: 1) as expected, the clearance of free VR and VS organisms after intraperitoneal injection into normal mice is equally efficient. 2) In vitro, VR bacteria are roughly twice as adherent to plasma coated PET surfaces as are VS organisms. 3) However, in vivo persistence of VS organisms preadherent to biomaterial implants is 5- to 10-fold better than that of preadherent VR organisms. The authors now believe that a discrete change in bacterial cell wall composition between VR and VS enterococci may contribute to the substantial differences in bacterial adhesion and survival of adherent organisms.

Animals↗
PubMed1992

Staphylococcus muscae, a new species isolated from flies.

A new coagulase-negative species of the genus Staphylococcus, Staphylococcus muscae, is described on the basis of the results of a study of four strains that were isolated from flies. 16S rRNA sequences of the type strains of S. muscae, Staphylococcus schleiferi, and Staphylococcus sciuri were determined and used, together with the corresponding sequences of Staphylococcus aureus and Staphylococcus epidermidis, for a comparative analysis. The new species is characterized taxonomically; this species is differentiated from the other novobiocin-susceptible staphylococci by its physiological and biochemical activities, cell wall composition, and levels of genetic relatedness. The type strain of this species is strain MB4 (= CCM 4175).

Animals↗
PubMed1994

Chemical and molecular classification of Saccharomonospora strains.

The results of our experiments showed that the 5'-terminal sequences of 23S rRNAs can be used to distinguish different genera of actinomycetes, including the genera Streptomyces, Micromonospora, Amycolatopsis, and Saccharomonospora. There are small differences (< 1%) among the sequences of some strains belonging to the genera Streptomyces (two strains) and Saccharomonospora (seven strains). On the basis of the results of morphological and biochemical analyses, strain 9022 belongs in the genus Saccharomonospora; however, there are distinct differences in the cell wall compositions and the 5' termini of the 23S rRNA sequences of this strain and members of the genus Saccharomonospora. Hence, strain 9022 cannot be classified in the genus Saccharomonospora.

Actinomycetales↗
PubMed1995

Staphylococcus pulvereri sp. nov., isolated from human and animal specimens.

A new coagulase-negative species of the genus Staphylococcus, Staphylococcus pulvereri, was isolated from human and animal specimens. The complete 16S rRNA sequence of the type strain of S. pulvereri, NT215, was determined and compared with the sequences of 16S rRNAs from the other staphylococci. Strains of S. pulvereri were differentiated from other novobiocin-resistant Staphylococcus species by their biochemical activities, cell wall composition, and levels of genetic relatedness. The type strain of this species is NT215 (= PCM 2443T).

Animals↗
PubMed1999

Agrococcus citreus sp. nov., isolated from a medieval wall painting of the chapel of Castle Herberstein (Austria).

A bacterial strain, D-1/1aT, isolated from a medieval wall painting of the chapel of Herberstein (Styria, Austria) was characterized by a polyphasic approach. Strain D-1/1aT shared 98.1% 16S rRNA sequence similarity to Agrococcus jenensis. The chemotaxonomic characteristics including polar lipid pattern, whole cell sugars, quinone system, polyamine pattern, cell wall composition and fatty acid profile were in good agreement with those of Agrococcus jenensis. The G+C content of the DNA was determined to be 74 mol%. The value of 47% DNA reassociation obtained after DNA-DNA hybridization between DNA of Agrococcus jenensis and strain D-1/1aT as well as differences in the amino acid composition of the peptidoglycan and in physiological characteristics demonstrate that the isolate represents a new species of the genus Agrococcus. The name Agrococcus citreus sp. nov. is proposed for the new species harbouring isolate D-1/1aT. The type strain is DSM 12453T.

Actinomycetales↗
PubMed2002

Agrococcus baldri sp. nov., isolated from the air in the 'Virgilkapelle' in Vienna.

Five coccoid, Gram-positive strains were isolated from the air of the 'Virgilkapelle' in Vienna. A representative of these five strains, V-108T, shared 99.0 and 98.4% 16S rDNA sequence similarity, respectively, with Agrococcus jenensis DSM 9580 and Agrococcus citreus DSM 12453T. Colonies of the five strains were white when grown in the dark and turned yellow in the light. The strains displayed highly similar biochemical and physiological characteristics and showed only small differences in their protein patterns obtained after SDS-PAGE. Based on Fourier-transform infra-red (FT-IR) spectra, the five strains were grouped together and separated from the other members of the genus, A. jenensis and A. citreus. Chemotaxonomic characteristics analysed from selected members of the five isolates, including polar lipids, quinone systems, polyamine patterns, cell wall composition and fatty acid profiles, were in good agreement with those of the two species of the genus Agrococcus described to date. The G+C content of the genomic DNA was determined to be within the narrow range of 73.8-74.9 mol%. The results of DNA-DNA hybridization with A. citreus DSM 12453T and A. jenensis DSM 9580T, as well as differences in biochemical/physiological characteristics, peptidoglycan composition, fatty acids, polar lipid profiles and FT-IR spectra, demonstrated that the five isolates represent a novel species of the genus Agrococcus. The name Agrococcus baldri sp. nov. is proposed for the novel species, of which strain V-108T (= DSM 14215T = CCM 4953T) is the type strain.

Actinomycetales↗
PubMed2002

Microbacterium aerolatum sp. nov., isolated from the air in the 'Virgilkapelle' in Vienna.

Three rod-shaped, Gram-positive strains were isolated from the air of the chapel 'Virgilkapelle' in Vienna. A representative of these three strains, strain V-73T, shared the highest 16S rDNA sequence similarities with members of the genus Microbacterium, in particular Microbacterium foliorum, Microbacterium testaceum, Microbacterium esteraromaticum, Microbacterium keratanolyticum and Microbacterium arabinogalactanolyticum. The strains displayed almost identical biochemical and physiological characteristics and showed no differences in their protein patterns obtained after SDS-PAGE. On the basis of Fourier-transform infra-red (FT-IR) spectra and genomic fingerprints, the three strains were grouped together and separated from the other relevant members of the genus Microbacterium. The chemotaxonomic characteristics analysed, including polar lipids, quinone systems, cell wall composition and fatty acid profiles, were in good agreement with the characteristics described for the genus Microbacterium. The G+C content of the DNAs was determined to be in the narrow range 69.3-69.7 mol %. The results of DNA-DNA hybridization, biochemical/physiological characterization, ERIC-PCR-generated genomic fingerprints and FT-IR spectra demonstrated that the three isolates represent a novel species of the genus Microbacterium. The name Microbacterium aerolatum sp. nov. is proposed for the novel species, of which strain V-73T (= DSM 14217T = CCM 4955T) is the type strain.

Actinomycetales↗