The effect of medium composition on the production of valine byCorynebacterium 9366-EMS/184

The auxotrophic mutantCorynebacterium 9366-EMS/184, requiring isoleuoine accumulates about 22 g of L-valine per litre after a 96 h cultivation in a medium containing 15% sucrose and 1% ammonium acetate.     

Effect of medium composition on the production of lysine byCorynebacterium sp. 9366-H-454

The strainCorynebacterium sp. 9366-H-454 grown on medium containing 10% sucrose and 4% corn-steep was found to produce as much as three times or four times (under laboratory conditions and on a pilot plant scale, respectively) more lysine than on the original. H-medium. The values are economical for a fermentation preparation of lysine.     

Optimisation of L-lysine production byCorynebacterium sp in fed-batch cultures

Summary The influence of initial concentration of glucose from 60 to 233 g/l on the production of L-lysine byCorynebacterium sp was studied first in batch culture. The maximum conversion rate into L-lysine was obtained at 165 g/l and the best specific production rate for L-lysine was observed at 65 g/l of glucose. In fed-batch fermentations, better conversion and the specific production rates were obtained. Maintaining of a high glucose concentration in the fed-batch technique allowed a 54% increase of the L-lysine production compared to the batch culture.     

Enantioselective biotransformations of racemic 2-aryl-3-methylbutyronitriles using Rhodococcus sp. AJ270

Rhodococcus sp. AJ270 is a useful biocatalyst for the synthesis of some enantiopure S-(+)-2-aryl-3-methylbutyric acids and R-(+)-2-aryl-3-methylbutyramides from the hydrolysis of 2-aryl-3-methylbutyronitriles under mild conditions. The nitrile-hydrolyzing enzymes involved in this novel microorganism are very sensitive to the steric effect of the para-substituent on the aromatic ring. While the nitrile hydratase displays a low S-enantioselectivity against nitriles, the amidase has a strict S-enantioselectivity against 2-aryl-3-methylbutyramides.     

Purification and characterization of the enantioselective nitrile hydratase from Rhodococcus sp. AJ270

Nitrile hydratase (NHase, EC 4.2.1.84) from Rhodococcus sp. AJ270 was purified with 23.96% yield after sonication, ammonium sulfate fractionation, ion exchange, hydrophobic and gel-filtration column chromatography. The enzyme showed intriguing characteristics: it hydrated not only aliphatic and heterocyclic nitriles but also aromatic ones. Some substrates were also hydrated enantioselectively to the corresponding amides. The enantiomeric excess (ee) value of the enzyme hydrating trans-2,2-dimethyl-3-phenylcyclopropanecarbonitrile was 84.7. The enzyme is composed of two subunits: an alpha subunit and beta subunit of 22 975 Da and 23 493 Da, respectively. The optimal temperature and pH for the catalytic reaction of the enzyme was 25 degrees C and pH 7.6. The enzyme activity of the purified NHase was strongly inhibited by some oxidizing agents and heavy metals.     

Formation of clavicipitic acid in cell-free systems of Claviceps sp.

4-Dimethylallyltryptophan-[3-¹⁴C] was converted to clavicipitic acid in cell-free extracts from Claviceps sp. SD 58 and Claviceps purpurea PRL 1980. Activity was concentrated in the microsomal fraction. Oxygen was required but there was no cofactor requirement. p-(Hydroxymercuri)benzoic acid strongly inhibited the conversion. Addition of diethyldithiocarbamate increased conversion 2·5 ×. Conversion was favored at high pH. Clavicipitic acid [¹⁴C] added to cultures of Claviceps sp. SD 58 was not significantly incorporated into elymoclavine.     

Formation of Glucose Isomerase by Streptomyces sp.

Sophoradin (I) [2′,4,4′-trihydroxy-3,3′,5-tris(3-methyl-2-butenyl)chalcone] which had been isolated from “Guang-Dou-Gen” (the root of Sophora subprostrata Chun et T. Chen) was synthesized through Claisen rearrangement. The reaction of p-hydroxybenzaldehyde and 3-chloro-3-methyl-1-butyne (III) gave 4-(1,1-dimethylpropargyloxy)benzaldehyde (VIII), which was catalytically hydrogenated over Lindlar catalyst to afford 4-(1,1-dimethylallyloxy)benzaldehyde (IX). IX was converted to 4-hydroxy-3-(3-methyl-2-butenyl)benzaldehyde (X) by Claisen rearrangement. The reaction of X and III gave 3-(3-methyl-2-butenyl)-4-(1,1-dimethylpropargyloxy)benzaldehyde (XI). Condensation of 2-hydroxy-4-(1,1-dimethylpropargyloxy)acetophenone (IV) and XI in alkaline solution gave a chalcone (XIII), which was catalytically hydrogenated over Lindlar catalyst to give 2′-hydroxy-4,4′-bis(1,-dimethylallyloxy)-3-(3-methyl-2-butenyl)chalcone (XIV). XIV was converted to I by Claisen rearrangement.     

Differences in the mutagenic and lethal effect of ethyl methansulphonate in the isolation of auxotrophic mutants of the strain corynebacterium sp. 9366

Folia Microbiologica -     

Oospore Formation in Phytophthora drechsleri f. sp. cajani

Phytophthora drechsleri f. sp. cajani (Pal et al.) Kannaiyan et al. causes stem and leaf blight in pigeon pea (Cajanus cajan [L.] Millsp.) in India. The asexual phase occurs in artificial culture as well as on the host tissue. Sparse oospore formation has been observed in old cultures. A technique has been evolved in which abundant mature oospores are formed on the leaflets of pigeon pea and also on glass slides using zoospores and mycelial discs on the former butonly mycelial discs on the glass slides. The largest number of oospores was formed after incubation for 36 h at 25°C.     

Biotin-vitamer Formation from Salicylic Acid by Pseudomonas sp.

Biotin-vitamer formation from salicylic acid was investigated. Strains of Pseudomonas sp., No. 102 and No. 362, isolated from soil samples utilized well salicylic acid as a sole source of carbon, and formed biotin-vitamers in culture broth. The metabolites were partially purified by the methods of active carbon adsorption and anion-exchange column chromatography, and clarified as desthiobiotin, bisnordesthiobiotin and 7-keto-8-aminopelargonic acid.     

Scale Formation in an Amoeba, Cochliopodium sp.

During excystment of an amoeba, Cochliopodium sp., scale formation was examined with light and electron microscopy. This amoeba was covered with scales. When the amoeba encysted, the scales remained on the external surface of the cyst wall. Soon after the induction of excystment the Golgi complex began to develop. Many vesicles were extruded from it and changed into vacuoles. Scales were observed first in the vacuole adjacent to the Golgi complex and later in inside the cyst wall. When the amoeba excysted it had been coated by the newly formed scales. It is suggested that the scale formation is dependent on the activity of the Golgi complex.     

Formation of Desthiobiotin from Oleic Acid by Brevibacterium sp.

Microbial formation of biotin-vitamers from oleic acid was investigated. Many strains of bacteria which were able to utilize oleic acid as a sole carbon source were isolated from soils and other natural materials. Among these bacteria, some strains formed a biotin-vitamer from oleic acid in the culture broth during the cultivation. The vitamer was purified from the culture broth of strain No. 23, and identified as desthiobiotin by chromatographical and biological methods.

From the results of investigation on the taxonomical characteristics, the bacterial strain No. 23 was assumed to be Brevibacterium sp.     

Achromobacter animicus sp. nov., Achromobacter mucicolens sp. nov., Achromobacter pulmonis sp. nov. and Achromobacter spiritinus sp. nov., from human clinical samples

The phenotypic and genotypic characteristics of fourteen human clinical Achromobacter strains representing four genogroups which were delineated by sequence analysis of nusA, eno, rpoB, gltB, lepA, nuoL and nrdA loci, demonstrated that they represent four novel Achromobacter species. The present study also characterized and provided two additional reference strains for Achromobacter ruhlandii and Achromobacter marplatensis, species for which, thus far, only single strains are publicly available, and further validated the use of 2.1% concatenated nusA, eno, rpoB, gltB, lepA, nuoL and nrdA sequence divergence as a threshold value for species delineation in this genus. Finally, although most Achromobacter species can be distinguished by biochemical characteristics, the present study also highlighted considerable phenotypic intraspecies variability and demonstrated that the type strains may be phenotypically poor representatives of the species. We propose to classify the fourteen human clinical strains as Achromobacter mucicolens sp. nov. (with strain LMG 26685^T [=CCUG 61961^T] as the type strain), Achromobacter animicus sp. nov. (with strain LMG 26690^T [=CCUG 61966^T] as the type strain), Achromobacter spiritinus sp. nov. (with strain LMG 26692^T [=CCUG 61968^T] as the type strain), and Achromobacter pulmonis sp. nov. (with strain LMG 26696^T [=CCUG 61972^T] as the type strain).     

Description of Tropicibacter mediterraneus sp. nov. and Tropicibacter litoreus sp. nov.

Four strains (M15∅_3, M17^T, M49 and R37^T) were isolated from Mediterranean seawater at Malvarrosa beach, Valencia, Spain. Together with an older preserved isolate (strain 2OM6) from cultured oysters at Vinaroz, Castellón, Spain, the strains were thoroughly characterized in a polyphasic study and were placed phylogenetically within the Roseobacter clade in the family Rhodobacteraceae. Highest 16S rRNA sequence similarities of the five strains to the types of any established species corresponded to Tropicibacter multivorans (95.8–96.4%), Phaeobacter inhibens (95.9–96.3%) and Phaeobacter gallaeciensis (95.9–96.2%). On the other hand, whole genome (ANI) and protein fingerprinting (MALDI-TOF) data proved: (i) non clonality among the strains, and (ii) the existence of two genospecies, one consisting of strains M15∅_3, M17^T, M49 and 2OM6 and another one consisting of strain R37^T. Phenotypic traits determined allow differentiating both genospecies from each other and from closely related taxa. In view of all data collected we propose to accommodate these isolates in two species as members of the genus Tropicibacter, Tropicibacter mediterraneus sp. nov. (type strain M17^T = CECT 7615^T = KCTC 23058^T) and Tropicibacter litoreus sp. nov. (type strain R37^T = CECT 7639^T = KCTC 23353^T).     

假丝酵母原生质体形成与再生的研究

本文研究了菌龄、酶系统、脱壁促进剂、渗透压稳定剂对假丝酵母Y002 原生质体形成与再生的影响。综合考虑形成率与再生率后,选用对数生长中期的菌体于1%蜗牛酶、 35℃下作用60分钟制备原生质体,并于以17%蔗糖作渗透压稳定剂的再生培养基中再生效果为好。     

Formation of Lyso-glycosphingolipids by Streptomyces sp

The actinomycete strain Streptomyces sp. H37 produces a novel glycosphingolipid-degrading enzyme. This strain was capable of converting ganglioside GM1 to lyso-GM1. After cultivation for 5 days in medium containing GM1, peptone, and detergent, GM1 was found to be almost completely converted to lyso-GM1. The product was purified on a DEAE-Sephadex A-25 column and thin layer chromatographies. The purified lyso-GM1 was hydrolyzed by endoglycoceramidase, and the released oligosaccharide moiety was identified as that of GM1 by HPLC using the pyridylaminoderivative method. The counterpart sphingosine moiety was confirmed with TLC. Moreover, the structure of lyso-GM1 was ascertained by ¹H-NMR analysis. The maximum formation of lyso-GM1 was found in 50mM potassium phosphate buffer (pH 7.5) containing 0.1% glycodeoxycholate. Various lyso-glycoshingolipids, including those of ganglio-, neolacto-, and globo-types, were formed from their parent glycosphingolipids using this strain.