J. Zemek

Antibiotic properties of lignin components.

Inhibitory effects of compounds with guaiacyl and syringyl structure, representing the structure of native lignin, were studied on model cultures of bacteria, yeasts, yeast-like microorganisms and moulds. Isoeugenol exhibited the most pronounced inhibitory effect on growth of the studied microorganisms.

Antimicrobial properties of aromatic compounds of plant origin.

The antimicrobial action of 11 compounds involving guaiacyl- and syringyl-like structures (low-molecular-weight part of lignin), gallic acid and its derivatives, cinnamic acid and its derivatives, veratric acid, anisic acid and crotonic acid (a total of 25 compounds) against bacteria, yeast-like organisms and protozoa was examined. Aromatic compounds modified in the C-side chain and aldehydes were effective preferentially againstTrichomonas vaginalis, whereas against bacteria and yeast-like organisms eugenol was the most effective inhibitor.

Crosslinked polyethylenimine: An enzyme carrier with spacers of various lengths introduced in crosslinking reaction

Abstract Polyethylenimine (PEI) reacted with epichlorhydrin to various degrees of crosslinking was further activated with thiophosgene or with succinic anhydride; the carboxyl derivatives obtained were converted to hydrazide derivatives. d -Glucose oxidase (β- d -glucose:oxygen 1-oxidoreductase, EC 1.1.3.4), glucoamylase (exo-1,4-α- d -glucosidase, 1,4-α- d -glucan glucohydrolase, EC 3.2.1.3) and cholinesterase (acetyl-, butyryl-) [acetylcholinesterase (acetylcholine acetylhydrolase, EC 3.1.1.7), butyryl cholinesterase (acylcholine acylhydrolase, EC 3.1.1.8)] were bound in their native forms to the first two types of carriers, while in the case of the hydrazide derivative of crosslinked PEI this occurred just after periodate oxidation of a glycoenzyme. The PEI derivatives prepared from the crosslinked PEI with the lowest degree of crosslinking, i.e. from that having the longest mean length of the spacer (∼ 11.1 A), revealed the best binding properties towards low-molecular thiols, amino acids and proteins/enzymes. After enzyme coupling, the isothiocyanate derivatives of crosslinked PEI gave preparations with the highest residual activities.

Polysaccharide-hydrolyzing enzymes in the GenusBacillus

The production of α-amylase, glucoamylase, Cx- and C1-cellulase, lichenase, xylanase and mannanase was followed in 118 strains of 25 species of the genusBacillus using specific substrates obtained by crosslinking of polysaccharides with 2-chloromethyloxiran. The α-amylase production was also followed using a chromolytic substrate.

Biochemical similarities among strains ofAureobasidium pullulans (de Bary) Arnaud

Seventy-seven properties ofAureobasidium pullulans including utilization of various carbon sources, decomposition of the lignin-cellulose complex and the respective enzymes were checked in the present communication. According to these properties the group of 43 strains was separated in three parts, out of which two groups were found to belong to varietiesA. pullulans var.pullulans andA. pullulans var.melanigenum. The third group formed a marginal part. The two varieties differed in numerous biochemical markers, particularly in the absence of monophenol monooxygenase in the varietyA. pullulans var.pullulans.

Production of α-amylase by microscopic fungi

The amylolytic activity and especially the production of α-amylase (EC 3.2.1.1) and α-glucosidase (EC 3.2.1.20) was screened in imperfect fungi, mucoral fungi and some ascomycetes. The character of the polysaccharide system, which is responsible for the utilization of α (1 → 4) glucan, was specified with a conoominant screening of growth on soluble starch. The amylolytic activity was found in 29 strains out of the 49 tested.

Antibacterial effect of some phenylhydrazones.

In earlier work we demonstrated an inhibitory effect of sugar hydrazones on bacterial growth most powerful being peracetylated D-erythrose and D-galactose derivatives (Zemek and Linek, 1977). The present paper is concerned with the effect of subst i tut ion by a nitro group in phenylhydrazones of D-galactose and the effect of hydroxyl group removal from the aldose moiety of 2,4-dinitrophenylhydrazone on the antibacterial action of these compounds. The antibacterial effect was also investigated in some nonsugar 2,4-dinitrophenylhydrazones. The antibacterial effects of individual phenylhydrazones were studied as shown earlier (Zemek and Linek, 1977). The substances were used in the form of dimethyl sulphoxide solutions, the final concentration of the solvent in the cultivation medium being maintained at 1 ~ The carbonyl compounds were commercially available, mostly from Koch-Light; D-mannose deoxy derivatives were prepared according to KuSs et al. (in press), 3-deoxy-n-r ibo-hexose was prepared according to Ku5Ar et al. (1975). Phenylhydrazones were prepared according to Lloyd and Doher ty (1952), acetylated derivatives according to Kovs et al. (1974). The results of anbibacterial act ivi ty assays are summarized in Tables I I I I . As seen from Table I, the antibacterial effect of all phenylhydrazine derivatives under s tudy was increased with the formation of the corresponding D-galactose hydrazones. The effect of subst i tut ion by a nitro groups on the aromatic ring is perceptible in particular with sugar 2,4-dinitrophenylhydrazones; 2-nitrophenyland 4-nitrophenylhydrazones exhibit a lower effect. The antibacterial ac t iv i ty of D-glucose and D-mannose monodeoxy derivatives is higher in the case of peracetylated hydrazone derivatives as compared with the

Antimicrobial effect of 4-Nitrophenylhydrazones, isonicotinoylhydrazones and N-4-Nitrophenylglycosylamines of D- and L-aldoses

The antibacterial effect of 19 4-mtrophenylhydrazones, isonicotinoylhydrazones, and N-4-nitrophenylhydrazones, of 9 mono- and 2 disaccharides was tested withMicrococcus luteus, Bacillus licheniformis andEscherichia coli.

Antimicrobial effect of sugar osazones and anhydro sugars

The antimicrobial effect of 14 sugar osazones and anhydro sugars was studied with model strains ofMicrococcus luteus, Bacillus licheniformis, Escherichia coli and strainsStaphylococcus aureus andPseudomonas aeruginosa isolated from clinical material. The relationship between the structure of these compounds, their solubility in water and 1-octanol and antimicrobial effect was investigated.

Antimicrobial effects of sugar osazones

Antimicrobial effects onMicrococcus luteus, Bacillus licheniformis andEscherichia coli were determined using a group of sixteen aldose osazones.