Cell-wall Type Research Articles

Macellibacteroides fermentans gen. nov., sp. nov., a member of the family Porphyromonadaceae isolated from an upflow anaerobic filter treating abattoir wastewaters

A novel obligately anaerobic, non-spore-forming, rod-shaped mesophilic bacterium, which stained Gram-positive but showed the typical cell wall structure of Gram-negative bacteria, was isolated from an upflow anaerobic filter treating abattoir wastewaters in Tunisia. The strain, designated LIND7H(T), grew at 20-45 °C (optimum 35-40 °C) and at pH 5.0-8.5 (optimum pH 6.5-7.5). It did not require NaCl for growth, but was able to grow in the presence of up to 2 % NaCl. Sulfate, thiosulfate, elemental sulfur, sulfite, nitrate and nitrite were not used as terminal electron acceptors. Strain LIND7H(T) used cellobiose, glucose, lactose, mannose, maltose, peptone, rhamnose, raffinose, sucrose and xylose as electron donors. The main fermentation products from glucose metabolism were lactate, acetate, butyrate and isobutyrate. The predominant cellular fatty acids were anteiso-C(15 : 0), C(15 : 0), C(17 : 0) 2-OH and a summed feature consisting of C(18 : 2)ω6,9c and/or anteiso-C(18 : 0), and the major menaquinones were MK-9, MK-9(H(2)) and MK-10. The G+C content of the genomic DNA was 41.4 mol%. Although the closest phylogenetic relatives of strain LIND7H(T) were Parabacteroides merdae, Parabacteroides goldsteinii and Parabacteroides gordonii, analysis of the hsp60 gene sequence showed that strain LIND7H(T) was not a member of the genus Parabacteroides. On the basis of phylogenetic inference and phenotypic properties, strain LIND7H(T) ( = CCUG 60892(T) = DSM 23697(T) = JCM 16313(T)) is proposed as the type strain of a novel species in a new genus within the family Porphyromonadaceae, Macellibacteroides fermentans gen. nov., sp. nov.

Anatomical Studies on Several Species of Heliotropium L. in Iran

Heliotropium spp. is distributed worldwide mainly in tropical and subtropical regions, with dry and warm temperate to semi-arid regions so that Southwest and center of Asia have considered as the main centre of origin and diversity of Heliotropium genus. Iran, with 32 species and 14 (sub) endemic species, has the highest diversity in the world followed by Pakistan and Turkey with 15 species and only one endemic species and the Arabian Peninsula with 15 species and three endemic species are in the next ranks. In order to anatomical studies on Heliotropium, twelve species of this genus were selected from different regions of Iran. The selected species included: H. bacciferum Forssk., H. ramossisimum BGE., H. brevilimb Boiss., H. transoxanum BGE., H. dasycarpum Ledeb, H. dyginum Forssk., H. aucheri Dc., H. carmanicum BGE. As perennial group and H. ellipticum Ledeb., H. lasiocarpum Fisch., H. suaveolens M.B. as annual group. In order to add more data to leaf anatomy characters, evaluating of systematic relevance and/or adaptive value of the morphological and anatomical diversity we have studied 24 anatomical characters in theses 12 species. For example shape and vascular bundles of main midrib, type of parenchyma cells located under lower epidermis of midrib, distance between vascular bundles and lower or upper epidermis, angle of between two parts of blade, number of cellular layers in lower or upper mesophylla, length of upper and lower mesophylla, type of cell wall in lower and upper mesophylla and thickness of lamina were investigated in this study. In order to this present obtained H. aucheri can be separated from H. carmanicum in H. aucheri subsp. carmanicum. It can be conclude that two species H. aucheri and H. carmanicum are independent species and can accept H. transoxanum as a sub group of H. dasycarpum.

Evolution of Multidrug Resistance during Staphylococcus aureus Infection Involves Mutation of the Essential Two Component Regulator WalKR

Antimicrobial resistance in Staphylococcus aureus is a major public health threat, compounded by emergence of strains with resistance to vancomycin and daptomycin, both last line antimicrobials. Here we have performed high throughput DNA sequencing and comparative genomics for five clinical pairs of vancomycin-susceptible (VSSA) and vancomycin-intermediate ST239 S. aureus (VISA); each pair isolated before and after vancomycin treatment failure. These comparisons revealed a frequent pattern of mutation among the VISA strains within the essential walKR two-component regulatory locus involved in control of cell wall metabolism. We then conducted bi-directional allelic exchange experiments in our clinical VSSA and VISA strains and showed that single nucleotide substitutions within either walK or walR lead to co-resistance to vancomycin and daptomycin, and caused the typical cell wall thickening observed in resistant clinical isolates. Ion Torrent genome sequencing confirmed no additional regulatory mutations had been introduced into either the walR or walK VISA mutants during the allelic exchange process. However, two potential compensatory mutations were detected within putative transport genes for the walK mutant. The minimal genetic changes in either walK or walR also attenuated virulence, reduced biofilm formation, and led to consistent transcriptional changes that suggest an important role for this regulator in control of central metabolism. This study highlights the dramatic impacts of single mutations that arise during persistent S. aureus infections and demonstrates the role played by walKR to increase drug resistance, control metabolism and alter the virulence potential of this pathogen.

Tissue‐specific biomass recalcitrance in corn stover pretreated with liquid hot‐water: Enzymatic hydrolysis (part 1)

Lignin content, composition, distribution as well as cell wall thickness, structures, and type of tissue have a measurable effect on enzymatic hydrolysis of cellulose in lignocellulosic feedstocks. The first part of our work combined compositional analysis, pretreatment and enzyme hydrolysis for fractionated pith, rind, and leaf tissues from a hybrid stay-green corn, in order to identify the role of structural characteristics on enzyme hydrolysis of cell walls. The extent of enzyme hydrolysis follows the sequence rind < leaves < pith with 90% conversion of cellulose to glucose in 24 h in the best cases. Physical fractionation of corn stalks or other C(4) grasses into soft and hard tissue types could reduce cost of cellulose conversion by enabling reduced enzyme loadings to hydrolyze soft tissue, and directing the hard tissue to other uses such as thermal processing, combustion, or recycle to the land from which the corn was harvested.

Cell wall polysaccharides from fern leaves: Evidence for a mannan-rich Type III cell wall in Adiantum raddianum

Primary cell walls from plants are composites of cellulose tethered by cross-linking glycans and embedded in a matrix of pectins. Cell wall composition varies between plant species, reflecting in some instances the evolutionary distance between them. In this work the monosaccharide compositions of isolated primary cell walls of nine fern species and one lycophyte were characterized and compared with those from Equisetum and an angiosperm dicot. The relatively high abundance of mannose in these plants suggests that mannans may constitute the major cross-linking glycan in the primary walls of pteridophytes and lycophytes. Pectin-related polysaccharides contained mostly rhamnose and uronic acids, indicating the presence of rhamnogalacturonan I highly substituted with galactose and arabinose. Structural and fine-structural analyses of the hemicellulose fraction of leaves of Adiantum raddianum confirmed this hypothesis. Linkage analysis showed that the mannan contains mostly 4-Man with very little 4,6-Man, indicating a low percentage of branching with galactose. Treatment of the mannan-rich fractions with endo-β-mannanase produced characteristic mannan oligosaccharides. Minor amounts of xyloglucan and xylans were also detected. These data and those of others suggest that all vascular plants contain xyloglucans, arabinoxylans, and (gluco)mannans, but in different proportions that define cell wall types. Whereas xyloglucan and pectin-rich walls define Type I walls of dicots and many monocots, arabinoxylans and lower proportion of pectin define the Type II walls of commelinoid monocots. The mannan-rich primary walls with low pectins of many ferns and a lycopod indicate a fundamentally different wall type among land plants, the Type III wall.

Comparative analysis of tertiary alcohol esterase activity in bacterial strains isolated from enrichment cultures and from screening strain libraries

The preparation of enantiopure tertiary alcohols is of great contemporary interest due to the application of these versatile building blocks in organic synthesis and as precursors towards high value pharmaceutical compounds. Herein, we describe two approaches taken towards the discovery of novel biocatalysts for the synthesis of these valuable compounds. The first approach was initiated with screening of 47 bacterial strains for hydrolytic activity towards the simple tertiary alcohol ester tert-butyl acetate. In conjunction, a second method focussed on the isolation of strains competent for growth on tert-butyl acetate as the sole source of carbon and energy. From functional screening, 10 Gram-positive Actinomycetes showed hydrolytic activity, whilst enrichment selection resulted in the identification of 14 active strains, of which five belong to the Gram-negative cell-wall type. Bacterial strains obtained from both approaches were viable for enantioselective hydrolysis of pyridine substituted tertiary alcohol esters in addition to bulky aliphatic and keto-derived substrates from the same class. Activity towards each of the test substrates was uncovered, with promising enantioselectivities of up to E = 71 in the hydrolysis of a para-substituted pyridine tertiary alcohol ester using a strain of Rhodococcus ruber. Interestingly strains of Microbacterium and Alcaligenes sp. gave opposite enantiopreference in the hydrolysis of a meta-substituted pyridine tertiary alcohol ester with E values of 17 and 54. These approaches show that via both possibilities, screening established strain collections and performing enrichment selection, it is possible to identify novel species which show activity towards sterically challenging substrates.

Seed Morphology of Some Species of &amp;lt;i&amp;gt;Indigofera&amp;lt;/i&amp;gt; (Fabaceae) from Saudi Arabia (Identification of Species and Systematic Significance)

Seeds of 18 species of Indigofera L. were examined with the scanning electron microscope and the light microscope. Macro- and micromorphological characters, including seed shape, colour, size, surface, epidermal cell shape, anticlinal boundaries, outer periclinal cell wall and relief of outer cell walls, are presented. Two types of basic anticlinal cell wall boundaries and two types of relief outer cell walls are recognized and two different shapes of the outer periclinal cell wall are described. A key for the identification of the investigated taxa based on seed characters is provided.

Actinomadura apis sp. nov., isolated from a honey bee (Apis mellifera) hive, and the reclassification of Actinomadura cremea subsp. rifamycini Gauze et al. 1987 as Actinomadura rifamycini (Gauze et al. 1987) sp. nov., comb. nov.

A Gram-reaction-positive aerobic actinomycete, designated strain IM17-1(T), was isolated from a honey bee (Apis mellifera) hive in Chiang Mai Province, Thailand. The strain formed a branched substrate mycelium and mature aerial mycelium bore short chains of arthrospores with warty surfaces. The cell wall contained meso-2,6-diaminopimelic acid (cell-wall type III) and the whole cell sugars were fucose, galactose, glucose, madurose, mannose and ribose. The major isoprenoid quinone was hexahydrogenated menaquinone with nine isoprene units and the predominant cellular fatty acids were C₁₆:₀ (33.8 %), C₁₈:₁ω9c (32.7 %), summed feature 3 (C₁₆:₁ω7c and/or iso-C₁₅:₀ 2-OH) (8.7 %) and 10-methyl C₁₈:₀ (8.2 %). The phospholipids were diphosphatidylglycerol, phosphatidylinositol and phosphatidylinositol mannosides. These morphological and chemotaxonomic characteristics were consistent with the classification of IM17-1(T) within the genus Actinomadura. Based on 16S rRNA gene sequence analysis, strain IM17-1(T) was closely related to the type strains of Actinomadura cremea subsp. cremea (98.1 %) and Actinomadura cremea subsp. rifamycini (98.6 %); however, it represented a distinct phylogenetic lineage from the other species within this genus. The unique genetic characteristics were reaffirmed by low levels of DNA-DNA relatedness between strain IM17-1(T) and the two most closely related type strains, A. cremea subsp. cremea JCM 3308(T) (56.5±4.9 %) and A. cremea subsp. rifamycini JCM 3309(T) (31.0±22.6 %), and further supported the proposal of IM17-1(T) as a novel species. Strain IM17-1(T) ( = JCM 16576(T) = TISTR 1980(T)) thus represents a novel species of the genus Actinomadura, for which the name Actinomadura apis sp. nov. is proposed. In addition, the genotypic and phenotypic data suggested the reclassification of Actinomadura cremea subsp. rifamycini Gauze et al. 1987 as a separate species, Actinomadura rifamycini sp. nov., comb. nov.

Reclassification of Leifsonia ginsengi (Qiu et al. 2007) as Herbiconiux ginsengi gen. nov., comb. nov. and description of Herbiconiux solani sp. nov., an actinobacterium associated with the phyllosphere of Solanum tuberosum L.

In the context of studying the effects of transgenic fructan-producing potatoes on the community structure of phyllosphere bacteria, a group of strains closely related to the species Leifsonia ginsengi was isolated. Phylogenetic analysis based on 16S rRNA gene sequences revealed that the new isolates and L. ginsengi DSM 19088(T) formed a lineage at the genus level and this finding was supported by chemotaxonomic characterization. The peptidoglycan type of the representative isolate, K134/01(T), and L. ginsengi DSM 19088(T) was B2γ, with d- and l-diaminobutyric acid as the diagnostic diamino acid and glycine, alanine and threo-3-hydroxyglutamic acid. The almost-complete substitution of glutamic acid by threo-3-hydroxyglutamic acid supported the differentiation of the new strains from recognized species of the genus Leifsonia. Furthermore, the detection of substantial amounts of the fatty acid cyclohexyl-C(17 : 0) in the new isolates and L. ginsengi DSM 19088(T) was a prominent chemotaxonomic feature for a clear demarcation of these strains from all genera of the family Microbacteriaceae that display the B2γ cell-wall type. Comparative phylogenetic and phenotypic analyses of the isolates and L. ginsengi DSM 19088(T) revealed the separate species status of the isolates. On the basis of these results, it is proposed that L. ginsengi should be classified as the type species of a novel genus, Herbiconiux gen. nov., with the name Herbiconiux ginsengi gen. nov., comb. nov. (type strain wged11(T) = CGMCC 4.3491(T) = JCM 13908(T) = DSM 19088(T) = NBRC 104580(T)). The phyllosphere isolates are assigned to a novel species, Herbiconiux solani sp. nov. (type strain K134/01(T) = DSM 19813(T) = LMG 24387(T) = NBRC 106740(T)).

Specific type of secondary cell wall formed by plant fibers

The review sums data indicating that, in many plant fibers, the secondary cell wall contains so-called gelatinous layers of peculiar structure along with those of common (xylan) structure. Sometimes these gelatinous layers comprise the main bulk of the cell wall. Key characteristics of gelatinous cell wall are presented and compared with those of classic xylan-type cell wall. The process of gelatinous cell wall formation is considered in detail for flax phloem fibers; several characteristic features of this process were revealed: intense rearrangement of already deposited cell-wall layers, unusual dynamics of Golgi vesicles, the occurrence of the stage-specific polysaccharide with specific properties, high activity of β-galactosidase, and the presence of substantial amount of free galactose. Similarity and differences in the gelatinous cell wall formation in the fibers of various plant species are discussed.

Seed morphology of some species of TephrosiaPers. (Fabaceae) from Saudi Arabia Identification of species and systematic significance

AbstractSeed morphology of eight species belonging to the genus Tephrosia Pers. were examined by using light and scanning electron microscopy. Macro‐ and micromorphological characters, including seed shape, colour, size, surface, epidermal cell shape, anticlinal boundaries, outer periclinal cell wall and relief of outer cell walls, are presented. Two types of basic anticlinal cell wall boundaries and two types of relief outer cell walls are recognized and two different shapes of the outer periclinal cell wall are described. A key for the identification of the investigated taxa based on seed characters is provided (© 2010 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)

Probing native lignin macromolecular configuration in Arabidopsis thaliana in specific cell wall types: Further insights into limited substrate degeneracy and assembly of the lignins of ref8, fah 1–2 and C4H::F5H lines

The interest in renewable, plant-derived, bioenergy/biofuels has resulted in a renaissance of plant cell-wall/lignin research. Herein, effects of modulating lignin monomeric compositions in a single plant species, Arabidopsis, are described. The earliest stage of putative "AcBr/Klason lignin" deposition was apparently unaffected by modulating p-coumarate 3-hydroxylase or ferulate 5-hydroxylase activities. This finding helps account for the inability of many other studies to fully suppress the reported putative levels of lignin deposition through monolignol biosynthesis manipulation, and also underscores limitations in frequently used lignin analytical protocols. The overall putative lignin content was greatly reduced (circa 62%) in a plant line harboring an H-(p-hydroxyphenyl) enriched lignin phenotype. This slightly increased H-monomer deposition level apparently occurred in cell-wall domains normally harboring guaiacyl (G) and/or syringyl (S) lignin moieties. For G- and S-enriched lignin phenotypes, the overall lignification process appeared analogous to wild type, with only xylem fiber and interfascicular fiber cells forming the S-enriched lignins. Laser microscope dissection of vascular bundles and interfascicular fibers, followed by pyrolysis GC/MS, supported these findings. Some cell types, presumably metaxylem and possibly protoxylem, also afforded small amounts of benzodioxane (sub)structures due to limited substrate degeneracy (i.e. utilizing 5-hydroxyconiferyl alcohol rather than sinapyl alcohol). For all plant lines studied, the 8-O-4' inter-unit frequency of cleavable H, G and/or S monomers was essentially invariant of monomeric composition for a given (putative) lignin content. These data again underscore the need for determination of lignin primary structures and identification of all proteins/enzymes involved in control of lignin polymer assembly/macromolecular configuration.

Fluorescence In Situ Hybridization for the Identification of Environmental Microbes

INTRODUCTIONThis protocol presents methods for the phylogenetic identification of microorganisms in environmental samples (e.g., water and sediments) by means of fluorescence in situ hybridization (FISH) with rRNA-targeted oligonucleotide probes, followed by signal amplification with catalyzed reporter deposition (CARD). In this procedure, FISH probes are conjugated with the enzyme horseradish peroxidase (HRP). After hybridization, the subsequent deposition of fluorescently labeled tyramides results in substantially higher signal intensities on target cells than after FISH with probes labeled directly with fluorochromes. This protocol describes the custom labeling of tyramides with different fluorochromes, as well as sample preparation and cell permeabilization strategies for various microbial cell wall types. A protocol for sequential multicolor CARD-FISH for the simultaneous detection of different phylogenetic groups is also presented.

Isolation and Characterization of Antagonistic Actinomycetes from Marine Soil

Soil sample was collected from the coastal region of Tamil Nadu with the aim of isolating actinobacteria and screen them for antagonistic activity against common bacterial and fungal pathogens. Serial dilution of the soil sample and subsequent screening of the isolates obtained, resulted in the identification of a potential strain VITDDK2 with significant activity against Klebsiella pneumoniae, Aspergillus flavus and Aspergillus niger. In addition, the strain VITDDK2 also possessed chitinolytic activity. Chemotaxonomic analysis showed that the isolate VITDDK2 belongs to cell wall Type I. 16 S rRNA partial gene sequence and phylogenetic analysis showed that the strain VITDDK2 shared 93% similarity with Streptomyces sp. strain 346. Also the secondary structure of the rRNA of VITDDK2 and the restriction sites were predicted using Genebee and NEBCutter softwares respectively.

Classification of ‘Anaerocellum thermophilum’ strain DSM 6725 as Caldicellulosiruptor bescii sp. nov.

The thermophilic, cellulolytic, anaerobic bacterium 'Anaerocellum thermophilum' strain Z-1320 was isolated from a hot spring almost two decades ago and deposited in the German Collection of Microorganisms and Cell Cultures (DSMZ) as DSM 6725. The organism was classified as representing a new genus, 'Anaerocellum', primarily on its growth physiology, cell-wall type and morphology. The results of recent physiological studies and of phylogenetic and genome sequence analyses of strain DSM 6725 of 'A. thermophilum' obtained from the DSMZ showed that its properties differed from those originally described for strain Z-1320. In particular, when compared with strain Z-1320, strain DSM 6725 grew at higher temperatures and had an expanded range of growth substrates. Moreover, the 16S rRNA gene sequence of strain DSM 6725 fell within the Caldicellulosiruptor clade. It is therefore suggested that 'Anaerocellum thermophilum' should be classified as a member of the genus Caldicellulosiruptor, for which the name Caldicellulosiruptor bescii sp. nov. is proposed (type strain DSM 6725(T)=ATCC BAA-1888(T)). C. bescii sp. nov. DSM 6725(T) is the most thermophilic cellulose-degrading organism known. The strain was able to grow up to 90 degrees C (pH 7.2) and degraded crystalline cellulose and xylan as well as untreated plant biomass, including potential bioenergy plants such as poplar and switchgrass.

CHEMOTAXONOMICAL IDENTIFICATION OF ACTINOBACTERIAL STRAINS ISOLATED FROM DAMP-AFFECTED OFFICE BUILDING

Four actinobacterial sporulating strains have been isolated from two damp-affected office buildings. They have been identified as streptomyces sp. (three strains) and cell wall type IV actinobacteria (one strain) by the chemotaxonomical approach.

Negativicoccus succinicivorans gen. nov., sp. nov., isolated from human clinical samples, emended description of the family Veillonellaceae and description of Negativicutes classis nov., Selenomonadales ord. nov. and Acidaminococcaceae fam. nov. in the bacterial phylum Firmicutes

Three strains of a hitherto unknown, Gram-negative, tiny, anaerobic coccus were collected from human clinical samples originating from skin and soft tissues. The three isolates displayed at least 99.9 % identity in their 16S rRNA gene sequences and more than 99.8 % identity in their dnaK gene sequences. The isolates were affiliated to the family Veillonellaceae, the coccobacillus Dialister micraerophilus being the most closely related species, but there was no more than 91.1 % identity in the 16S rRNA gene sequence between this species and the three isolates. Phylogeny based on the 16S rRNA gene confirmed that the three strains represent a novel and robust lineage within the current family Veillonellaceae. A similar genomic structure was demonstrated for the three isolates by PFGE-based analysis. Morphology and metabolic end products, as well as genotypic and phylogenetic data supported the proposal of the novel genus Negativicoccus gen. nov., with the novel species Negativicoccus succinicivorans sp. nov. [type strain ADV 07/08/06-B-1388(T) (=AIP 149.07(T)=CIP 109806(T)=DSM 21255(T)=CCUG 56017(T)) as type species]. Phylogenetic analyses based on the 16S rRNA gene sequences of members of the phylum Firmicutes and other phyla indicated that the family Veillonellaceae forms a robust lineage clearly separated from those of the classes 'Bacilli', 'Clostridia', Thermolithobacteria and 'Erysipelotrichi' in the phylum Firmicutes. Therefore, we propose that this family is a class-level taxon in the phylum Firmicutes, for which the name Negativicutes classis nov. is proposed, based on the Gram-negative type of cell wall of its members, with the type order Selenomonadales ord. nov. In this order, a novel family, Acidaminococcaceae fam. nov., is proposed and description of the family Veillonellaceae is emended.

Thiohalobacter thiocyanaticus gen. nov., sp. nov., a moderately halophilic, sulfur-oxidizing gammaproteobacterium from hypersaline lakes, that utilizes thiocyanate

A moderately halophilic, obligately chemolithoautotrophic, sulfur-oxidizing bacterium, designated strain HRh1(T), was obtained from mixed sediment samples from hypersaline chloride-sulfate lakes in the Kulunda Steppe, in south-western Siberia (Russia), using aerobic enrichment culture at 1 M NaCl with thiocyanate as substrate. Cells of the isolate were short, non-motile rods with a Gram-negative type of cell wall. The bacterium was an obligate aerobe capable of chemolithoautotrophic growth with thiocyanate and thiosulfate. With thiosulfate, it grew at NaCl concentrations of 0.2-3.0 M (optimum 0.5 M) and at pH 6.3-8.0 (optimum pH 7.3-7.5). During growth on thiocyanate, cyanate was identified as an intermediate. The dominant cellular fatty acids were C(16 : 0) and C(18 : 1)omega7. Phylogenetic analysis based on 16S rRNA gene sequencing placed the isolate in the class Gammaproteobacteria as an independent lineage, with an unclassified marine sulfur-oxidizing bacterium as the closest culturable relative (93 % sequence similarity). A single cbbL gene (coding for the key enzyme of the Calvin-Benson cycle of autotrophic CO(2) assimilation) with relatively low similarity to any homologous genes found in chemolithoautotrophs was detected in strain HRh1(T). On the basis of our phenotypic and phylogenetic analysis, the halophilic isolate is proposed to represent a new genus and novel species, Thiohalobacter thiocyanaticus gen. nov., sp. nov. The type strain of Thiohalobacter thiocyanaticus is HRh1(T) (=DSM 21152(T) =UNIQEM U249(T)).

Hemolytic activity of Streptomyces VITSDK1 spp. isolated from marine sediments in Southern India

A moderately halophilic actinomycete strain was isolated from marine sediments collected at the Marakkanam coast of Tamil Nadu, India. The taxonomic position was evaluated by polyphasic approach and the strain was identified as a member of the genus Streptomyces. The strain is congruent with the description of the genus Streptomyces due to the characteristics of white aerial cell mass, spiral spore chains and a rough spore surface, menaquinones of MK-9 (H4, H2 and H6) types and belongs to cell-wall type I. The G + C content of the isolated DNA is 71.3 mol% and the 16S rRNA sequence of the strain shows a maximum of 93% similarity with Streptomyces HBUM 49447. The comparison of phenotypic data of closest strains with the isolate clearly indicates that our strain belongs to the genus Streptomyces. Based on the phenotypic and phylogenetic analysis, the strain was classified as a new species of the genus Streptomyces and designated as VITSDK1. The media and cultural conditions for maximal growth have been optimized under shake-flask conditions by measuring the dry weight of the mycelium. The maximal growth was attained with the use of optimized production medium, pH of 7.2 and incubation temperature of 27 °C. The growth of the strain was salt concentration dependent and maximal growth was attained at 15% salt concentration which indicates the halophilic nature of the isolate. Streptomyces VITSDK1 spp. exhibits significant hemolytic activity against rat erythrocytes with the EC50 value of 127 μg/ml and for human erythrocytes 168 μg/ml. Further, it shows moderate antibiosis against fungi and bacterial pathogens. Une souche d’actinomycète modérément halophile a été isolée de sédiments marins récoltés sur la côte de Marakkanam du Tamil Nadu à l’est de l’Inde. La souche a été identifiée comme appartenant au genre Streptomyces. Elle est conforme à la description du genre Streptomyces par ses caractéristiques de culture, ses chaînes spiralées de spores à paroi rugueuse, ses ménaquinones MK-9 (H2, H4 et H6) et son appartenance à la paroi de type I. Le G + C de l’ADN isolé est de 73 % et la séquence du 16S ARN montre un maximum de similarité de 93 % avec la souche de Streptomyces HBUM 49447. La comparaison des travaux sur le phénotype de souches proches avec la souche isolée montre clairement qu’elle appartient au genre Streptomyces. Compte tenu de l’analyse phénotypique et génotypique, elle a été identifiée comme une nouvelle souche du genre Streptomyces et dénommée VITSDK1. Les milieux et les conditions de culture pour une croissance maximale ont été optimisés en culture en ballons agités par la mesure du poids sec du mycélium. Le maximum de culture est atteint à l’aide d’un milieu optimisé, à pH 7,2 et à température de 27 °C. La croissance de la souche est concentration dépendante en sel et la croissance maximale est obtenue pour 15 % de concentration saline qui montre l’halophilie de cette souche. Streptomyces VITSDK1 sp. montre une activité hémolytique significative contre les érythrocytes de souris et les érythrocytes humains avec une EC50 respectivement de 127 et 168 μg/ml. Par ailleurs, elle montre une activité antimicrobienne modérée contre des champignons et des bactéries pathogènes.

Sciscionella marina gen. nov., sp. nov., a marine actinomycete isolated from a sediment in the northern South China Sea

The taxonomic position of an actinomycete, designated SCSIO 00231(T), isolated from a sediment sample collected from the northern South China Sea, was determined by using a polyphasic approach. The organism formed fragmented substrate hyphae and sparse aerial mycelium on modified ISP 2 medium. Phylogenetic analysis based on the 16S rRNA gene sequence showed that strain SCSIO 00231(T) fell into the family Pseudonocardiaceae, in which it formed a distinct lineage and was loosely associated with Thermocrispum municipale DSM 44069(T), with 93 % similarity. The other closest phylogenetic neighbours were Saccharopolyspora erythraea NRRL 2338(T) (92.6 % similarity) and Amycolatopsis sacchari DSM 44468(T) (93.1 % similarity). The isolate had cell-wall type IV (meso-diaminopimelic acid and whole-cell sugars arabinose, galactose and glucose) and phospholipid type III. The predominant menaquinone was MK-9(H(4)). The G+C content of the genomic DNA was 69 mol%. Based on these data, strain SCSIO 00231(T) can be readily distinguished from previously described organisms and represents a new genus within the family Pseudonocardiaceae. The name Sciscionella gen. nov. is proposed, with the novel species Sciscionella marina sp. nov. The type strain of Sciscionella marina is SCSIO 00231(T) (=KCTC 19433(T) =CCTCC AA208009(T)).