[The effects of geomagnetic storms on proteinase and glycosidase activities in fish intestinal mucosa]

It has been demonstrated that the glycosidase activity of cyprinoid fishes (carp and crucian carp) exposed to a geomagnetic storm for up to 20 h considerably decreases; however, the proteinase activity is weakly altered (a statistically significant decrease in the enzyme activity has been observed only in fasting fish). An in vitro study of the effects of individual half hour intervals of the geomagnetic storm that correspond to the main and recovery phases on the same enzyme activities demonstrates the opposite trend. Independently of the experimental conditions, geomagnetic storms have been shown to influence the enzyme system of fasting fish negatively.

Chemoenzymatic synthesis of α-L-rhamnosides using recombinant α-L-rhamnosidase from Aspergillus terreus

This study describes an efficient, large scale fermentation of a recombinant α-L-rhamnosidase originating from Aspergillus terreus. High-cell-density Pichia pastoris fermentation resulted in yields up to 627 U/L/h. The recombinant enzyme was used for the reverse rhamnosylation of various small organic compounds. A full factorial experimental design setup was applied to identify the importance of temperature, substrate concentrations, solvent type and concentration as well as the acidity of the reaction mixture. Careful optimization of these parameters allowed the synthesis of a range of α-L-rhamnosides among which cyclohexyl α-L-rhamnopyranoside, anisyl α-L-rhamnopyranoside and 2-phenylethyl α-L-rhamnopyranoside. In addition, α-L-rhamnosylation of phenolic hydroxyls in phenols such as hydroquinone, resorcinol, catechol and phenol was observed, which is a rather unique reaction catalyzed by glycosidases.

High-level expression of Bacillus naganoensis pullulanase from recombinant Escherichia coli with auto-induction: effect of lac operator

Pullulanase plays an important role in specific hydrolysis of branch points in amylopectin and is generally employed as an important enzyme in starch-processing industry. So far, however, the production level of pullulanase is still somewhat low from wide-type strains and even heterologous expression systems. Here the gene encoding Bacillus naganoensis pullulanase was amplified and cloned. For expression of the protein, two recombinant systems, Escherichia coli BL21(DE3)/pET-20b(+)-pul and E. coli BL21(DE3)/pET-22b(+)-pul, were constructed, both bearing T7 promoter and signal peptide sequence, but different in the existance of lac operator and lacI gene encoding lac repressor. Recombinant pullulanase was initially expressed with the activity of up to 14 U/mL by E. coli BL21(DE3)/pET-20b(+)-pul with IPTG induction in LB medium, but its expression level reduced continually with the extension of cryopreservation time and basal expression was observed. However, E. coli BL21(DE3)/pET-22b(+)-pul , involving lac operator downstream of T7 promoter to regulate foreign gene transcription, exhibited pullulanase activity consistently without detected basal expression. By investigating the effect of lac operator, basal expression of foreign protein was found to cause expression instability and negative effect on production of target protein. Thus double-repression strategy was proposed that lac operators in both chromosome and plasmid were bound with lac repressor to repress T7 RNA polymerase synthesis and target protein expression before induction. Consequently, the total activity of pullulanase was remarkably increased to 580 U/mL with auto-induction by lac operator-involved E. coli BL21(DE3)/pET-22b(+)-pul. When adding 0.6% glycine in culture, the extracellular production of pullulanase was significantly improved with the extracellular activity of 502 U/mL, which is a relatively higher level achieved to date for extracellular production of pullulanase. The successful expression of pullulanase with lac operator regulation provides an efficient way for enhancement of expression stability and hence high-level production of target protein in recombinant E. coli.

Optimization of pullulanase production in Escherichia coli by regulation of process conditions and supplement with natural osmolytes

In this study, the effects of temperature, IPTG (Isopropyl β-D-1-thiogalactopyranoside) concentration, and osmolytes (proline, K-glutamate, and betaine) on cell growth and soluble pullulanase productivity of recombinant Escherichia coli were investigated. The yield of soluble pullulanase was found to be enhanced with decrease in cultivation temperature, lower IPTG concentration, and betaine supplementation in a shake flask. In addition, a modified two-stage feeding strategy was proposed and applied in a 3-L fermentor supplied with 20mM betaine, which achieved a dry cell weight of 59.3 g L(-1). Through this cultivation approach at 25 °C, the total soluble activity of pullulanase reached 963.9 U mL(-1), which was 8.3-fold higher than that observed without addition of betaine at 30 °C (115.8 U mL(-1)). The higher expression of soluble pullulanase in a scalable semisynthetic medium showed the potential of the proposed process for the industrial production of soluble enzyme.

Cell wall components of Leptosphaeria maculans enhance resistance of Brassica napus

Preparations with elicitation activity were obtained from the mycelium of Leptosphaeria maculans , a fungal pathogen of oilseed rape (Brassica napus). Crude delipidated and deproteinized extract from fungal cell walls induced expression of pathogenesis related gene 1 (PR1), hydrogen peroxide accumulation, and enhanced resistance of B. napus plants toward infection by L. maculans. Elicitation activity significantly decreased after treatment of a crude extract with α- or β-glucanase. Monosaccharide composition analysis of a crude extract purified by ion-exchange chromatography revealed glucose (∼58 mol %), mannose (∼22 mol %), and galactose (∼18 mol %) as the major sugars. FT-IR and NMR spectra confirmed the presence of both carbohydrate and polypeptide components in the purified product. Correlation NMR experiments defined trisaccharide bound to O-3 of serine residue α-D-Glcp-(1→2)-β-D-Galf-(1→6)-α-D-Manp-(1→3)-L-Ser. Terminal α-D-Glcp and (1→6)-β-D-glucan were also detected. The obtained results strongly support the conclusion that these carbohydrates induce defense response in B. napus plants.

Experimental mixture design as a tool to enhance glycosyl hydrolases production by a new Trichoderma harzianum P49P11 strain cultivated under controlled bioreactor submerged fermentation

This work investigates the glycosyl hydrolase (GH) profile of a new Trichoderma harzianum strain cultivated under controlled bioreactor submerged fermentation. The influence of different medium components (delignified steam-exploded sugarcane bagasse, sucrose, and soybean flour) on GH biosynthesis was assessed using experimental mixture design (EMD). Additionally, the effect of increased component concentrations in culture media selected from the EMD was studied. It was found that that a mixed culture medium could significantly maximize GH biosynthesis rate, especially for xylanase enzymes which achieved a 2-fold increment. Overall, it was demonstrated that T. harzianumP49P11 enzymes have a great potential to be used in the deconstruction of biomass.

Isolation and characterization of an agarase-producing bacterial strain, Alteromonas sp. GNUM-1, from the West Sea, Korea

The agar-degrading bacterium GNUM-1 was isolated from the brown algal species Sargassum serratifolium, which was obtained from the West Sea of Korea, by using the selective artificial seawater agar plate. The cells were Gram-negative, 0.5-0.6 micrometer wide and 2.0-2.5 micrometer long curved rods with a single polar flagellum, forming nonpigmented, circular, smooth colonies. Cells grew at 20 degrees C- 37 degrees C, between pH 5.0 and 9.0, and at 1-10% (w/v) NaCl. The DNA G+C content of the GNUM-1 strain was 45.5 mol%. The 16S rRNA sequence of the GNUM-1 was very similar to those of Alteromonas stellipolaris LMG 21861 (99.86% sequence homology) and Alteromonas addita R10SW13 T (99.64% sequence homology), which led us to assign it to the genus Alteromonas. It showed positive activities for agarase, amylase, gelatinase, alkaline phosphatase, esterase (C8), lipase (C14), leucine arylamidase, valine arylamidase, alpha-chymotrypsin, acid phosphatase, naphthol- AS-BI-phosphohydrolase, alpha-galactosidase, beta-galactosidase, beta-glucosidase, catalase, and urease. It can utilize citrate, malic acid, and trisodium citrate. The major fatty acids were summed feature 3 (21.5%, comprising C16:1omega7c/iso- C15:0 2-OH) and C16:0 (15.04%). On the basis of the variations in many biochemical characteristics, GNUM-1 was considered as unique and thus was named Alteromonas sp. GNUM-1. It produced the highest agarase activity in modified ASW medium containing 0.4% sucrose, but lower activity in rich media despite superior growth, implying that agarase production is tightly regulated and repressed in a rich nutrient condition. The 30 kDa protein with agarase activity was identified by zymography, and this report serves as the very first account of such a protein in the genus Alteromonas.

High level lipid production by a novel inulinase-producing yeast Pichia guilliermondii Pcla22

In this study, an inulinase-producing yeast strain Pcla22 of Pichia guilliermondii was identified. It was found that the yeast strain Pcla22 could produce higher amount of oil and more lipid bodies in its cells than any other yeast strains tested in this study. Under the optimal conditions, 60.6%(w/w) of lipid based on cell dry weight, 20.4 g/l of the dry cell mass, SCO produced per g of consumed sugar of 0.19 g/g and biomass produced per g of consumed sugar of 0.32 g/g were obtained in the culture of the yeast strain Pcla22 after 96 h of the fed-batch fermentation. Over 79.8% of the fatty acids from the yeast strain Pcla22 grown in the oil production medium containing inulin was C(16:0) and C(18:1), especially C(18:1) (57.9%). The biodiesel obtained from the produced lipid could be burnt well.

Structural diversity of streptococcal mutans synthesized under different culture and environmental conditions and its effect on mutanase synthesis

Streptococcal mutans synthesized under different conditions by growing cultures or by their glucosyltransferases were shown to exhibit a great structural and property diversity. Culturing and environmental factors causing structural differences in mutans were specified. All of the obtained biopolymers (76 samples) were water-insoluble and most of them (72) had a structure with a predominance of α-(1→3)-linked glucose (i.e., the content of α-(1→3)-linkages in the glucan was always higher than 50%, but did not exceed 76%). An exception were four glucans containing more than 50% of α-(1→6)-sequences. In these structurally unique mutans, the ratio of α-(1→3)- to α-(1→6)-bonds ranged from 0.75 to 0.97. Aside from one polymer, all others had a heavily branched structures and differed in the number of α-(1→3), α-(1→6), and α-(1→3,6) linkages and their mutual proportion. The induction of mutanase production in shaken flask cultures of Trichoderma harzianum by the structurally diverse mutans resulted in enzyme activities ranging from 0.144 to 1.051 U/mL. No statistical correlation was found between the total percentage content of α-(1→3)-linkages in the α-glucan and mutanase activity. Thus, despite biosynthetic differences causing structural variation in the mutans, it did not matter which mutan structures were used to induce mutanase production.

L-rhamnose induction of Aspergillus nidulans α-L-rhamnosidase genes is glucose repressed via a CreA-independent mechanism acting at the level of inducer uptake

BACKGROUND

Little is known about the structure and regulation of fungal α-L-rhamnosidase genes despite increasing interest in the biotechnological potential of the enzymes that they encode. Whilst the paradigmatic filamentous fungus Aspergillus nidulans growing on L-rhamnose produces an α-L-rhamnosidase suitable for oenological applications, at least eight genes encoding putative α-L-rhamnosidases have been found in its genome. In the current work we have identified the gene (rhaE) encoding the former activity, and characterization of its expression has revealed a novel regulatory mechanism. A shared pattern of expression has also been observed for a second α-L-rhamnosidase gene, (AN10277/rhaA).

RESULTS

Amino acid sequence data for the oenological α-L-rhamnosidase were determined using MALDI-TOF mass spectrometry and correspond to the amino acid sequence deduced from AN7151 (rhaE). The cDNA of rhaE was expressed in Saccharomyces cerevisiae and yielded pNP-rhamnohydrolase activity. Phylogenetic analysis has revealed this eukaryotic α-L-rhamnosidase to be the first such enzyme found to be more closely related to bacterial rhamnosidases than other α-L-rhamnosidases of fungal origin. Northern analyses of diverse A. nidulans strains cultivated under different growth conditions indicate that rhaA and rhaE are induced by L-rhamnose and repressed by D-glucose as well as other carbon sources, some of which are considered to be non-repressive growth substrates. Interestingly, the transcriptional repression is independent of the wide domain carbon catabolite repressor CreA. Gene induction and glucose repression of these rha genes correlate with the uptake, or lack of it, of the inducing carbon source L-rhamnose, suggesting a prominent role for inducer exclusion in repression.

CONCLUSIONS

The A. nidulans rhaE gene encodes an α-L-rhamnosidase phylogenetically distant to those described in filamentous fungi, and its expression is regulated by a novel CreA-independent mechanism. The identification of rhaE and the characterization of its regulation will facilitate the design of strategies to overproduce the encoded enzyme - or homologs from other fungi - for industrial applications. Moreover, A. nidulans α-L-rhamnosidase encoding genes could serve as prototypes for fungal genes coding for plant cell wall degrading enzymes regulated by a novel mechanism of CCR.

[The Black Sea bacteria--producers of hydrolytic enzymes]

Investigation of 15 different glycoside activities of 64 strains isolated from water and invertebra of the Black Sea has shown that 64% of the studied strains displayed the capacity to synthesize enzymes with alpha-L-ramnosidase activity which varied from 0.01 to 0.20 un/ml depending on the strain. The greatest number of the enzyme producers was found in representatives of Alteromonas macleodii. Other investigated glycosidase activities: alpha-amylase, beta-N-acetyl-D-glucosaminidase, beta-D-glucuronide, alpha-N-acetyl-D-galactosaminidase, beta-N-acetyl-D-galactosaminidase, beta-D-galactosidase, alpha-D-galactosidase, beta-D-glucosidase, KM-cellulase activities though have been found, but mainly with inconsiderable indices, alpha-D-glucosidase, alpha-D-mannosidase, alpha-L-fucosidase, beta-D-xylosidase and alpha-D-xylosidase activities were found in neither of the studied strains. Strains with rather high proteolytic activity were found among marine species of bacteria. It has been established that 18 strains (28%) of 64 marine isolates were characterized by rather high level of total proteolytic activity (from 0.1 to 05 un/ml), 43.75% of them displayed inconsiderable (up to 0.1 un/ml) or only trace (up to 0.01 un/ml), 18.75% did not display any hydrolytic activity in respect of casein. Investigation of substrate specificity to a number of fibrillar and globular proteins of 9 studied strains, which displayed considerable general (caseinolytic) activity has shown that 8 of them displayed fibrinolytic activity from 0.15 to 2.175 un/ml. All 9 strains were characterized by gelatin activity. Collagenase and keratinase activity was also revealed. Neither of 9 studied strains displayed elastase activity.

[Optimization of cultivation conditions of alpha-L-rhamnosidases producers-- representatives of different taxonomic groups of microorganisms]

Influence ofsome technological parameters of cultivation ofproducers Cryptococcus albidus, Eupenicillinum erubescens, Bacillus sp. on the process of synthesis of extracellular enzyme alpha-L-rhamnosidase has been studied. The authors have determined optimal sources of carbon (0.2-0.3% rhamnose) and nitrogen (0.2% sodium nitrate for C. albidus and E. erubescens and ammonium sulphate for Bacillus sp.) (the ratio 1:2), cultivation temperature (28 degrees C, 25 degrees C, 42 degrees C, respectively) for maximum synthesis of alpha-L-rhamnosidase. Use of the medium with initial pH value from 4 to 8 was most efficient for all the studied strains. The maximum level of alpha-L-rhamnosidase activity of E. erubescens and Bacillus sp. was established at the value of sulphite number of 0.44, while for C. albidus--it was 0.56. Maximum alpha-L-rhamnosidase activity of C. albidus, E. erubescens, Bacillus sp. is achieved at 4, 8 days and 27 hours of cultivation, respectively. The cultures being grown in selected conditions, the alpha-L-rhamnosidase synthesis has increased by 30, 50 and 20%, respectively.

Direct conversion of inulin and extract of tubers of Jerusalem artichoke into single cell oil by co-cultures of Rhodotorula mucilaginosa TJY15a and immobilized inulinase-producing yeast cells

In this study, it was found that the immobilized inulinase-producing cells of Pichia guilliermondii M-30 could produce 169.3 U/ml of inulinase activity while the free cells of the same yeast strain only produced 124.3 U/ml of inulinase activity within 48 h. When the immobilized inulinase-producing yeast cells were co-cultivated with the free cells of Rhodotorula mucilaginosa TJY15a, R. mucilaginosa TJY15a could accumulate 53.2% oil from inulin in its cells and cell dry weight reached 12.2g/l. Under the similar conditions, R. mucilaginosa TJY15a could accumulate 55.4% (w/w) oil from the extract of Jerusalem artichoke tubers in its cells and cell dry weight reached 12.8 g/l within 48 h. When the co-cultures were grown in 2l fermentor, R. mucilaginosa TJY15a could accumulate 56.6% (w/w) oil from the extract of Jerusalem artichoke tubers in its cells and cell dry weight reached 19.6g/l within 48 h. Over 90.0% of the fatty acids from the yeast strain TJY15a grown in the extract of Jerusalem artichoke tubers was C(16:0), C(18:1) and C(18:2), especially C(18:1) (50.6%).

[Identification in the rat olfactory epithelium new subgroup YM-1 chitinase-like protein]

Novel protein with a molecular mass of ~43 kDa from rat olfactory epithelium in pathophysiological conditions was discovered. Its amino acid sequence and affiliation with the family 18 glycohydrolase subgroup of chitinase-like proteins YM-1 were determined.

[TL, the new bacteriophage of Pseudomonas aeruginosa and its application for the search of halo-producing bacteriophages]

The properties of new virulent bacteriophage TL of Pseudomonas aeruginosa belonging to the family Podoviridae (genome size of 46 kb) were investigated. This bacteriophage is capable of lysogenizing the bacterial lawn in halo zones around negative colonies (NC) of other bacteriophages. TL forms large NC, that are hardly distinguishable on the lawn of P. aeruginisa PAO1. At the same time, on the lawns of some phage-resistant PAO1 mutants, as well as on those produced by a number of clinical isolates, TL forms more transparent NC. It is suggested that more effective growth of the bacteriophage TL NC is associated with the differences in outer lipopolysaccharide (LPS) layer of the cell walls of different bacterial strains, as well as of the bacteria inside and outside of the halos. This TL property was used to optimize selection of bacteriophages producing halos around NC on the lawn of P. aeruginosa PAO1. As a result, a group of bacteriophages differing in the patterns of interaction between their halos and TL bacteriophage, as well as in some characters was identified. Taking into consideration the importance of cell-surfaced structures of P. aeruginosa in manifestation of virulence and pathogenicity, possible utilization of specific phage enzymes, polysacchadide depolymerases, for more effective treatment of P. aeruginosa infections is discussed.

[Optimization of cultivation conditions of Cryptococcus albidus--producers of alpha-L-rhamnosidase]

The influence of content of cultivation media and fermentation conditions on synthesis of alpha-L-rhamnosidase by Cryptococcus albidus 1001 and 1003 were studied. It was shown that L-rhamnose and NaNO, are the optimum sources of carbon and nitrogen, respectively. The temperature of 25 degrees C, pH 6.0, growing in 50 ml of the medium at rotation rate 220 rev/min during 6 days are optimum parameters for both strains.

[Transgenic tomato plants expressing recA and NLS-recA-licBM3 genes as a model for studying meiotic recombination]

Homologous DNA recombination in eukaryotes is necessary to maintain genome stability and integrity and for correct chromosome segregation and formation of new haplotypes in meiosis. At the same time, genetic determination and nonrandomness of meiotic recombination restrict the introgression of genes and generation of unique genotypes. As one of the approaches to study and induce meiotic recombination in plants, it is recommended to use the recA gene of Escherichia coli. It is shown that the recA and NLS-recA-licBM3 genes have maternal inheritance and are expressed in the progeny of transgenic tomato plants. Plants expressing recA or NLS-recA-licBM3 and containing one T-DNA insertion do not differ in pollen fertility from original nontransgenic forms and can therefore be used for comparative studies of the effect of bacterial recombinases on meiotic recombination between linked genes.

A novel glycosylation signal regulates transforming growth factor beta receptors as evidenced by endo-beta-galactosidase C expression in rodent cells

The αGal (Galα1-3Gal) epitope is a xenoantigen that is responsible for hyperacute rejection in xenotransplantation. This epitope is expressed on the cell surface in the cells of all mammals except humans and Old World monkeys. It can be digested by the enzyme endo-β-galactosidase C (EndoGalC), which is derived from Clostridium perfringens. Previously, we produced EndoGalC transgenic mice to identify the phenotypes that would be induced following EndoGalC overexpression. The mice lacked the αGal epitope in all tissues and exhibited abnormal phenotypes such as postnatal death, growth retardation, skin lesion and abnormal behavior. Interestingly, skin lesions caused by increased proliferation of keratinocytes suggest the role of a glycan structure [in which the αGal epitope has been removed or the N-acetylglucosamine (GlcNAc) residue is newly exposed] as a regulator of signal transduction. To verify this hypothesis, we introduced an EndoGalC expression vector into cultured mouse NIH3T3 cells and obtained several EndoGalC-expressing transfectants. These cells lacked αGal epitope expression and exhibited 1.8-fold higher proliferation than untransfected parental cells. We then used several cytokine receptor inhibitors to assess the signal transduction cascades that were affected. Only SB431542 and LY364947, both of which are transforming growth factor β (TGFβ) receptor type-I (TβR-I) inhibitors, were found to successfully reverse the enhanced cell proliferation rate of EndoGalC transfectants, indicating that the glycan structure is a regulator of TβRs. Biochemical analysis demonstrated that the glycan altered association between TβR-I and TβR-II in the absence of ligands.

Polysaccharidase and glycosidase production of avicel grown rumen fungus Orpinomyces sp. GMLF5

Extracellular and cell-associated enzyme preparations were obtained from ruminal anaerobic fungi Orpinomyces sp. GMLF5 grown in culture containing microcrystalline cellulose (avicel) as sole energy source and degradation capacities of the preparations towards several polysaccharides and glycosides were studied. Fungus showed substantial increases in xylanase, carboxymethyl cellulase (CMCase), lichenase, amylase, beta-xylosidase, beta-glucosidase and alpha-L-arabinofuranosidase activities between 72 and 168 hours. High amounts of cell associated beta-xylosidase were noted in 4 and 5 days old cultures. Optimum temperature and pH of the polysaccharidases were found at 50 degrees C and 6.0-6.5, respectively. Xylanase was found to be virtually stable at 50 degrees C, CMCase and lichenase were stable at 40 degrees C for 200 min, however amylase was found more sensitive to heat treatment. The fibrolytic enzymes of the isolate GMLF5 were observed to be capable of hydrolyze the avicel.

Production of multifunctional chimaeric enzymes in plants: a promising approach for degrading plant cell wall from within

Multifunctional chimaeric hydrolases can be created by covalently linking heterologous catalytic and functional domains in a single polypeptide. Previously, we have generated a number of chimaeric lignocellulosic hydrolases that contain two to five modules [Biotechnol Bioeng (2009) 102: 1045; Appl Environ Microbiol (2009) 75: 1754]. These chimaeras closely resemble the parental enzymes in kinetics and other enzymatic properties, and some exhibit improved synergy in degrading natural substrates when compared to mixtures of parental enzymes. In addition to the applications in fermentative enzyme production, the chimaeric genes can be used in the construction of a single plant transformation binary vector carrying several genes that encode a complete set of lignocellulosic hydrolase activities. The advantages of this approach include ease in vector construction and transformation, as well as downstream plant analysis and breeding. The hydrolases sequestered in biomass feedstock can potentially assist enzymatic pretreatment and sugar conversion. Here, we report the gene expression and functional characterization of a chimaeric hemicellulase in transgenic tobacco plants. T1 transgenic plants produced up to 19-mg active enzymes per gram of total-soluble leaf proteins. The results demonstrate the feasibility of producing multifunctional lignocellulosic hydrolases in plants. Key considerations in the design, construction and plant expression of the chimaeric genes are discussed.

Capsule depolymerase overexpression reduces Bacillus anthracis virulence

Capsule depolymerase (CapD) is a gamma-glutamyl transpeptidase and a product of the Bacillus anthracis capsule biosynthesis operon. In this study, we examined the effect of modulating capD expression on B. anthracis capsule phenotype, interaction with phagocytic cells and virulence in guinea pigs. Transcriptional fusions of capD were made to the genes encoding heat-shock protein 60 (hsp60) and elongation factor Tu (EFTu), and to capA, a B. anthracis capsule biosynthesis gene. Translation signals were altered to improve expression of capD, including replacing the putative ribosome-binding site with a consensus sequence and the TTG start codon with ATG. CapD was not detected by immunoblotting in lysates from wild-type B. anthracis Ames but was detected in strains engineered with a consensus ribosome-binding site for capD. Strains overexpressing capD at amounts detected by immunoblotting were found to have less surface-associated capsule and released primarily lower-molecular-mass capsule into culture supernatants. Overexpression of capD increased susceptibility to neutrophil phagocytic killing and adherence to macrophages and resulted in reduced fitness in a guinea pig model of infection. These data suggest that B. anthracis may have evolved weak capD expression resulting in optimized capsule-mediated virulence.

Heterologous expression, crystallization and preliminary X-ray characterization of CcCel6C, a glycoside hydrolase family 6 enzyme from the basidiomycete Coprinopsis cinerea

CcCel6C is a gene that encodes a glycoside hydrolase family 6 (GH6) enzyme in the Coprinopsis cinerea genome. In the evolutionary tree of GH6 enzymes, the encoded enzyme was closely related to Cel6B from Humicola insolens, previously called endoglucanase VI, while its amino-acid sequence revealed a region corresponding to the C-terminal active-site-enclosing loop typical of cellobiohydrolase II. Here, the crystallization of CcCel6C produced in Escherichia coli is reported. The square prismatic crystal belonged to the triclinic space group P1, with unit-cell parameters a = 44.04, b = 45.11, c = 48.90 A, alpha = 77.81, beta = 87.34, gamma = 68.79 degrees. Diffraction data were collected to 1.6 A resolution.

[O-glycosylhydrolases of embryos of the sea urchin Strongylocentrotus intermedius and effect of some natural substances on their biosynthesis]

Embryos of sea urchin Strongylocentrotus intermedius have been revealed to contain o-glycosylhydrolases: highly active 1,3-beta-D-glucanase and alpha-D-mannosidase as well as a lower activity of beta-D-glucosidase and beta-D-galactosidase. Dynamics of changes of the enzyme activities has been studied at various stages of the sea urchin embryo development. There also have been studied effects of some substances (natural fucoidans, beta-1,3; 1,6-glucans formed by enzymatic synthesis as well as a protein inhibitor of marine mollusc endo-1,3-beta-D-glucanases) on development of the embryos and biosynthesis of 1,3-beta-D-glucanase and alpha-D-mannosidase.

Production of extracellular exoinulinase from Kluyveromyces marxianus YS-1 using root tubers of Asparagus officinalis

Root tubers of Asparagus officinalis were used as a source of raw inulin for the production of exoinulinase (EC 3.2.1.7) from Kluyveromyces marxianus YS-1. Root extract prepared at 10kg/cm2 pressure for 10min showed maximum inulinase production. Medium components and process parameters were standardized to improve the enzyme production. Inulinase yield of 40.2IU/mL in a medium containing raw inulin (3.5%), beef extract (2%), SDS (0.001%), Mn2+ (2.0mM), Mg2+ (1.5mM), Co2+ (2mM) and pH 6.5 has been obtained under agitation (150rpm) after 60h of incubation at 30 degrees C at shake flask level. After optimization, the enzyme production was 4.8 times more than the basal medium. To test the feasibility of raw inulin from A. officinalis for the production of inulinase, trials were also made in a bioreactor (1.5L). Inulinase activity of 50.2IU/mL was obtained from raw inulin (4.0%) under agitation (200rpm) and aeration (0.75vvm) at 30 degrees C after 60h of fermentation. Inulinase yield in bioreactor was almost six times higher than the basal medium used initially in shake flask.