Saccharopolyspora mangrovi sp. nov., a novel mangrove soil actinobacterium with distinct metabolic potential revealed by comparative genomic analysis.

A novel mangrove soil-derived actinomycete, strain S2-29T, was found to be most closely related to Saccharopolyspora karakumensis 5K548T based on 16 S rRNA sequence (99.24% similarity) and genomic phylogenetic analyses. However, significant divergence in digital DNA-DNA hybridization, average nucleotide identity, and unique biosynthetic gene cluster possession distinguished S2-29T as a distinct Saccharopolyspora species. Pan genome evaluation revealed exceptional genomic flexibility in genus Saccharopolyspora, with > 95% accessory genome content. Strain S2-29T harbored 718 unique genes, largely implicated in energetic metabolisms, indicating different metabolic capacities from its close relatives. Several uncharacterized biosynthetic gene clusters in strain S2-29T highlighted the strain's untapped capacity to produce novel functional compounds with potential biotechnological applications. Designation as novel species Saccharopolyspora mangrovi sp. nov. (type strain S2-29T = JCM 34,548T = CGMCC 4.7716T) was warranted, expanding the known Saccharopolyspora diversity and ecology. The discovery of this mangrove-adapted strain advances understanding of the genus while highlighting an untapped source of chemical diversity.

Comparative transcriptomic analysis of two Saccharopolyspora spinosa strains reveals the relationships between primary metabolism and spinosad production.

Saccharopolyspora spinosa is a well-known actinomycete for producing the secondary metabolites, spinosad, which is a potent insecticides possessing both efficiency and safety. In the previous researches, great efforts, including physical mutagenesis, fermentation optimization, genetic manipulation and other methods, have been employed to increase the yield of spinosad to hundreds of folds from the low-yield strain. However, the metabolic network in S. spinosa still remained un-revealed. In this study, two S. spinosa strains with different spinosad production capability were fermented and sampled at three fermentation periods. Then the total RNA of these samples was isolated and sequenced to construct the transcriptome libraries. Through transcriptomic analysis, large numbers of differentially expressed genes were identified and classified according to their different functions. According to the results, spnI and spnP were suggested as the bottleneck during spinosad biosynthesis. Primary metabolic pathways such as carbon metabolic pathways exhibited close relationship with spinosad formation, as pyruvate and phosphoenolpyruvic acid were suggested to accumulate in spinosad high-yield strain during fermentation. The addition of soybean oil in the fermentation medium activated the lipid metabolism pathway, enhancing spinosad production. Glutamic acid and aspartic acid were suggested to be the most important amino acids and might participate in spinosad biosynthesis.

Saccharopolyspora coralli sp. nov. a novel actinobacterium isolated from the stony coral Porites.

A novel Gram-stain-positive, aerobic, non-motile actinobacterium, designated strain E2AT, was isolated from a coral sample and examined using a polyphasic taxonomic approach. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain E2AT formed a distinct phyletic lineage in the genus Saccharopolyspora and was closely related to S. cavernae CCTCC AA 2012022T (96.4 %) and S. lacisalsi CCTCC AA 2010012T (95.3 %). The isolate grew at 15-35 °C, pH 5-12 and in the presence of 1-16 % (w/v) NaCl. The cell-wall diamino acid was meso-DAP. Major fatty acids identified were iso-C15 : 0, iso-C16 : 0 and C17 : 1 ω8c. The predominant menaquinone was MK-9(H4). The polar lipids detected were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylmethylethanolamine, one unidentified glycolipid, one unidentified phospholipid and one unidentified aminolipid. The genomic DNA G+C content was 68.6 mol%. Based on the data from the polyphasic taxonomic study reported here, strain E2AT represents a novel species within the genus Saccharopolyspora, for which the name Saccharopolyspora coralli sp. nov. is proposed. The type strain is E2AT=(JCM 31844T=MCCC 1A17150T).

Saccharopolyspora: an underexplored source for bioactive natural products.

Actinomycetes are a rich source for secondary metabolites with a diverse array of biological activities. Among the various genera of actinomycetes, the genus Saccharopolyspora has long been recognized as a potential source for antibiotics and other therapeutic leads that belong to diverse classes of natural products. Members of the genus Saccharopolyspora have been widely reported from several natural sources including both terrestrial and marine environments. A plethora of this genus has been chemically investigated for the production of novel natural products with interesting pharmacological effects. Therefore, Saccharopolyspora is considered one of the pharmaceutical important genera that could provide further chemical diversity with potential lead compounds. In this review, the literature from 1976 until December 2018 was covered, providing a comprehensive survey of all natural products derived from this genus and their semi-synthetic derivatives along with their biological activities, whenever applicable. Moreover, the biological diversity of Saccharopolyspora species and their habitats were also discussed.

Saccharopolyspora qinghaiensis sp. nov., a novel actinobacterium isolated from a salt lake.

A novel halophilic, Gram-positive and aerobic actinobacterium, designated strain AFM 20147T, was isolated from a sediment sample collected from Xiaochaidan Salt Lake of Qinghai, China. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain AFM 20147T belongs to the genus Saccharopolyspora, shows high sequence similarities to Saccharopolyspora griseoalba AFM 10238T (99.41%) and Saccharopolyspora halophila YIM 90500T (98.20%), and has low similarities (below 98.0%) with other members of the genus. The DNA-DNA relatedness values of strain AFM 20147T with S. griseoalba AFM 10238T and S. halophila YIM 90500T were 40 ± 1.7% and 37 ± 2.3%, respectively. Optimal growth was found to occur at 28 °C, pH 7.5 and in the presence of 7.5% (w/v) NaCl. Strain AFM 20147T was found to contain meso-diaminopimelic acid as the cell wall diamino acid, and galactose and arabinose as the whole cell sugars. The major fatty acids were identified as iso-C15:0, iso-C16:0 and anteiso-C17:0. The major polar lipids were identified as diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylmethylethanolamine, phosphatidylinositol and phosphatidylcholine. MK-9(H4) was found to be the predominant menaquinone and the DNA G+C content was determined to be 67.8 mol%. DNA-DNA relatedness data, together with phenotypic and chemotaxonomic differences, clearly distinguish the isolate from its close neighbours. On the basis of the data from this polyphasic analysis, a novel species Saccharopolyspora qinghaiensis sp. nov. is proposed. The type strain is S. qinghaiensis AFM 20147T (=KCTC 49190T =CGMCC 4.7556T).

Saccharopolyspora rhizosphaerae sp. nov., an actinomycete isolated from rhizosphere soil in Thailand.

A novel actinomycete, designated as strain H219T, was isolated from rhizosphere soil collected under an Elephant ear plant (Colocasiaesculenta) in Bangkok, Thailand. Strain H219T was characterised using a polyphasic approach. Phylogenetic analysis of the 16S rRNA gene sequences revealed that this isolate was most closely related to Saccharopolyspora tripterygii JCM 32123T (97.6 %), Saccharopolyspora dendranthemae NBRC 108675T (97.5 %) and Saccharopolyspora flava NBRC 16345T (97.5 %). However, DNA-DNA hybridization analyses showed a low relatedness in the range of 39-48 % between the novel isolate and the above closely related strains. The cell-wall peptidoglycan of strain H219T contained meso-diaminopimelic acid. The diagnostic whole-cell sugars consisted of arabinose and galactose. The cellular fatty acid profile mainly comprised iso-C16 : 0, anteiso-C17 : 0, iso-C15 : 0, and 10-methyl C17 : 0. The major menaquinone was MK-9(H4). The detected phospholipids were diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylethanolamine-containing hydroxylated fatty acids and an unknown phospholipid. The DNA G+C content was 70.6 mol%. Strain H219T represented chemotaxonomic and morphological characteristics that were consistent with members of the genus Saccharopolyspora. However, strain H219T could be distinguished from closely related strains by several phenotypic properties. Based on the data from the polyphasic studies, we propose that strain H219T is a novel species within the genus Saccharopolyspora, Saccharopolysporarhizosphaerae sp. nov. The type strain is H219T (=TBRC 8564T=NBRC 113388T).

Saccharopolyspora maritima sp. nov., an actinomycete isolated from mangrove sediment.

A novel Saccharopolyspora strain, designated 3SS5-12T, isolated from mangrove sediment collected from Ranong Province is described. The strain was characterized by pale yellow branching aerial mycelium which differentiated into flexuous chains of spores covered with tufts of short curved hairs. The whole-cell hydrolysates of the strain contained meso-diaminopimelic acid as the diagnostic diamino acid, with arabinose, galactose and ribose as the main sugars. A major menaquinone of this strain was MK-9(H4). Mycolic acids were absent. The DNA G+C content of the genomic DNA was 69.4 mol%. The predominant cellular fatty acids were iso-C16 : 0 and anteiso-C17 : 0. Polar lipids consisted of diphosphatidylglycerol, hydroxy-phosphatidylethanolamine, hydroxy-phosphatidylmonomethylethanolamine, phosphatidylethanolamine, phosphatidylmonomethylethanolamine, phosphatidylcholine, phosphatidylglycerol, phosphatidylinositol, unidentified phospholipids and unidentified lipids. Phylogenetic determination based on 16S rRNA gene sequences indicated that the organism was classified in the genus Saccharopolyspora and highly similar to Saccharopolyspora jiangxiensis W12T (98.8 % sequence similarity), Saccharopolyspora hirsutasubsp. kobensis JCM 9109T (98.8 %), Saccharopolyspora antimicrobica I05-00074T (98.2 %) and Saccharopolyspora indica VRC122T (98.1 %). Evidence from the chemotaxonomic, phenotypic and molecular systematic data indicated that strain 3SS5-12T should be classified as a representing novel species of the genus Saccharopolyspora, for which the name Saccharopolyspora maritima sp. nov. is proposed. The type strain is 3SS5-12T (=TBRC 7048T=NBRC 112863T).

Saccharopolyspora deserti sp. nov., a novel halotolerant actinobacterium isolated from a desert.

Strain SYSU D8010T was isolated from a desert sand sample collected in Saudi Arabia. The taxonomic position of the isolate was investigated by the polyphasic taxonomic approach. The isolate was found to be Gram-positive and aerobic. The strain was able to grow at 14-40 °C, pH 5.0-9.0 and in the presence of up to 22 % (w/v) NaCl. Strain SYSU D8010T contained meso-diaminopimelic acid as cell-wall diamino acid, and arabinose, fucose, galactose, glucose and rhamnose as the whole-cell sugars. The primary polar lipids were diphosphatidylglycerol, phosphatidylcholine, phosphatidylglycerol, phosphatidylinositol and phosphatidylinositolmannosides. Menaquinone MK-9(H4) was detected as the respiratory quinone; and anteiso-C17 : 0, iso-C16 : 0, iso-C15 : 0 and iso-C17 : 0 as the predominant fatty acids. Pairwise comparison of the 16S rRNA gene sequences indicated that strain SYSU D8010T had a sequence similarity of 97.8 % to Saccharopolyspora halophila YIM 90500T. The genomic DNA G+C content of strain SYSU D8010T was determined to be 69.9 mol%. Based on the analyses of the phenotypic, genotypic and phylogenetic characteristics, strain SYSU D8010T was determined to represent a novel species of the genus Saccharopolyspora, for which the name Saccharopolyspora deserti sp. nov. is proposed. The type strain of the species is SYSU D8010T (=KCTC 39989T=CPCC 204620T).

Eis, a novel family of arylalkylamine N-acetyltransferase (EC 2.3.1.87).

Enhanced intracellular survival (Eis) proteins were found to enhance the intracellular survival of mycobacteria in macrophages by acetylating aminoglycoside antibiotics to confer resistance to these antibiotics and by acetylating DUSP16/MPK-7 to suppress host innate immune defenses. Eis homologs composing of two GCN5 N-acetyltransferase regions and a sterol carrier protein fold are found widely in gram-positive bacteria. In this study, we found that Eis proteins have an unprecedented ability to acetylate many arylalkylamines, are a novel type of arylalkylamine N-acetyltransferase AANAT (EC 2.3.1.87). Sequence alignment and phyletic distribution analysis confirmed Eis belongs to a new aaNAT-like cluster. Among the cluster, we studied three typical Eis proteins: Eis_Mtb from Mycobacterium tuberculosis, Eis_Msm from Mycobacterium smegmatis, and Eis_Sen from Saccharopolyspora erythraea. Eis_Mtb prefers to acetylate histamine and octopamine, while Eis_Msm uses tyramine and octopamine as substrates. Unlike them, Eis_Sen exihibits good catalytic efficiencies for most tested arylalkylamines. Considering arylalkylamines such as histamine plays a fundamental role in immune reactions, future work linking of AANAT activity of Eis proteins to their physiological function will broaden our understanding of gram-positive pathogen-host interactions. These findings shed insights into the molecular mechanism of Eis, and reveal potential clinical implications for many gram-positive pathogens.

Saccharopolyspora aidingensis sp. nov., an actinomycete isolated from a salt lake.

A novel halophilic actinomycete strain, designated TRM 46074T, was isolated from Aiding salt lake in Turpan Basin, north-west China. Strain TRM 46074T was aerobic, Gram-stain-positive and grew optimally with 12 % (w/v) NaCl. The strain was observed to produce sparse aerial mycelium with long chains of spores that were non-motile and oval or spherical in shape with a rough or smooth surface; substrate mycelium was branched and well developed. The cell wall was determined to contain meso-diaminopimelic acid; the diagnostic whole-cell sugars were galactose, arabinose and ribose. The diagnostic polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, phosphatidylglycerol and phosphatidylinositol. The predominant menaquinones were MK-9(H4), MK-10(H8) and MK-10(H4). The G+C content of the DNA was 70.9 mol%. The major fatty acids were anteiso-C17 : 0, iso-C15 : 0, iso-C16 : 0 and iso-C17 : 0. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain TRM 46074T belongs to the genus Saccharopolyspora. Strain TRM 46074T had 16S rRNA gene sequence similarity of 99.6 % with the closest described species, Saccharopolyspora ghardaiensis H53T. DNA-DNA hybridization between strain TRM 46074T and Saccharopolysporaghardaiensis H53T showed 58.6 % relatedness. On the basis of the evidence from a polyphasic study, strain TRM 46074T is considered to represent a novel species in the genus Saccharopolyspora, for which the name Saccharopolyspora aidingensis sp. nov. is proposed. The type strain is TRM 46074T (=CCTCC AA 2012014T=JCM 30185T).

Salinifilum gen. nov., with description of Salinifilum proteinilyticum sp. nov., an extremely halophilic actinomycete isolated from Meighan wetland, Iran, and reclassification of Saccharopolyspora aidingensis as Salinifilum aidingensis comb. nov. and Saccharopolyspora ghardaiensis as Salinifilum ghardaiensis comb. nov.

A Gram-positive, halophilic actinobacterial strain Miq-12T was isolated from Meighan wetland in Iran. Strain Miq-12T was strictly aerobic, catalase positive and oxidase negative. The isolate grew at 12-25 % NaCl, at 30-50 °C and pH 5.5-10.5. The optimum NaCl, temperature and pH for growth were 15-20 %, 40 °C and 7.0-8.0, respectively. The cell wall of strain Miq-12T contained meso-diaminopimelic acid as diagnostic diamino acid and arabinose as whole-cell sugar. The polar lipid pattern consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine and phosphatidylinositol. It synthesized cellular fatty acids of anteiso and iso-branched types, anteiso-C17 : 0, iso-C17:0, iso-C15:0, iso-C16 : 0. The major respiratory quinone was MK-9(H4). The G+C content of its genomic DNA was 72.1 mol%. Phylogenetic analysis based on 16S rRNA gene sequence comparison revealed that strain Miq-12T belongs to the family Pseudonocardiaceae, constituted a separate clade, and showed the closest phylogenetic similarity to Saccharopolyspora aidingensis TRM 46074T (96.99 %) and Saccharopolyspora ghardaiensis CCUG 63370T (96.92 %). On the basis of phylogenetic analysis, phenotypic and chemotaxonomic characteristics, a novel genus and species of the family Pseudonocardiaceae, Salinifilum proteinilyticum gen. nov., sp. nov., are proposed. The type strain is Miq-12T (=IBRCM 11033T=LMG 28390T). We also propose that S. aidingensis and S. ghardaiensis should be transferred to this new genus and be named Salinifilum aidingensis comb. nov. and Salinifilum ghardaiensis comb. nov., respectively. The type strain of Salinifilum aidingensis comb. nov. is TRM 46074T (=CCTCCAA 2012014T=JCM 30185T) and the type strain of Salinifilum ghardaiensis comb. nov. is CCUG 63370T (=DSM 45606T=CECT 8304T).

Saccharopolyspora hattusasensis sp. nov., isolated from soil.

A Saccharopolyspora strain, designated CR3506T, isolated from a soil sample collected from Sungurlu, Corum, Turkey, was examinated using a polyphasic approach. Phylogenetic analysis based on an almost-complete 16S rRNA gene sequence analysis showed that the strain is closely related to the type strains of Saccharopolyspora spinosa NRRL 18395T (99.1%), Saccharopolyspora phatthalungensis NRRL B-24798T (98.4%) and Saccharopolyspora shandongensis 88T (98.1%); low levels of DNA-DNA relatedness were found between the isolate and S. spinosa and S. phatthalungensis (<50%). Strain CR3506T was found to have chemotaxonomic and phylogenetic properties consistent with its classification in the genus Saccharopolyspora. The strain contained meso-diaminopimelic acid as the diagnostic diamino acid. Whole-cell hydrolysates contained arabinose and galactose. The polar lipids were identified as phosphatidylmethylethanolamine, phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylcholine, phosphatidylglycerol and phosphatidylinositol. The predominant menaquinones (>10%) were MK-9(H4) and MK-8(H4). Major fatty acids were (>10%) iso-C16:0, C15:03OH, C18:0 and iso-C15:0. Further, the morphological, physiological and biochemical characteristics of strain CR3506T are distinct from S. spinosa and other species of the genus Saccharopolyspora with which this strain has high 16S rRNA gene sequence similarity (98.0-98.5%). Strain CR3506T has antimicrobial activity against Bacillus subtilis NRRL B-209, Citrobacter freundi NRRL B-2643 and Staphylococcus aureus ATCC 29213. Consequently, it is proposed that strain CR3506T represents a novel Saccharopolyspora species for which the name Saccharopolyspora hattusasensis sp. nov. is proposed. The type strain is CR3506T (=KCTC 29104T = DSM 45715T).

Saccharopolyspora spongiae sp. nov., a novel actinomycete isolated from the marine sponge Scopalina ruetzleri (Wiedenmayer, 1977).

A novel marine actinomycete, designated strain CMAA 1452T, was isolated from the sponge Scopalina ruetzleri collected from Saint Peter and Saint Paul Archipelago, in Brazil, and subjected to a polyphasic taxonomic investigation. The organism formed a distinct phyletic line in the Saccharopolyspora 16S rRNA gene tree and had chemotaxonomic and morphological properties consistent with its classification in this genus. It was found to be closely related to Saccharopolyspora dendranthemae KLBMP 1305T (99.5% 16S rRNA gene sequence similarity) and shared similarities of 99.3, 99.2 and 99.0 % with 'Saccharopolyspora endophytica' YIM 61095, Saccharopolyspora tripterygii YIM 65359T and 'Saccharopolyspora pathumthaniensis' S582, respectively. DNA-DNA relatedness values between the isolate and its closest phylogenetic neighbours, namely S. dendranthemae KLBMP 1305T, 'S. endophytica' YIM 61095 and S. tripterygii YIM 65359T, were 53.5, 25.8 and 53.2 %, respectively. Strain CMAA 1452T was also distinguished from the type strains of these species using a range of phenotypic features. On the basis of these results, it is proposed that strain CMAA 1452T (=DSM 103218T=NRRL B-65384T) merits recognition as the type strain of a novel Saccharopolyspora species, Saccharopolyspora spongiae sp. nov.

Saccharopolyspora griseoalba sp. nov., a novel actinomycete isolated from the Dead Sea.

A novel halotolerant actinomycete, designated strain AFM 10238T, was isolated from a sediment sample collected from the Dead Sea of Israel. The isolate grew at 15-45 °C, pH 6-12 and with 0-15 % (w/v) NaCl. Strain AFM 10238T contains meso-diaminopimelic acid as cell wall diamino acid, and galactose and arabinose as the whole cell sugars. The major polar lipids are phosphatidylcholine, phosphatidylglycerol, and diphosphatidylglycerol. Major fatty acids are iso-C16:0, iso-C17:0, iso-C15:0, anteiso-C17:0 and C17:1 ω8c. MK-9(H4) is the predominant menaquinone and the DNA G + C content is 72.7 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain AFM10238T belongs to the genus Saccharopolyspora. The 16S rRNA gene sequence similarity between strain AFM 10238T and its close neighbours, Saccharopolyspora halophila YIM 90500T , Saccharopolyspora spinosa DSM 44228T, Saccharopolyspora dendranthemae KLBMP 1305T and Saccharopolyspora cebuensis DSM 45019T were 98.2, 97.2, 97.1 and 97.0 %, respectively. Sequence similarities to other type strains of this genus were below 97 %. DNA-DNA relatedness data, together with phenotypic and chemotaxonomic differences, clearly distinguished the isolate from its close neighbours. On the basis of the data from this polyphasic analysis, a novel species Saccharopolyspora griseoalba sp. nov. is proposed. The type strain is AFM 10238T (= DSM 46,663 = CGMCC 4.7124).

Saccharopolyspora subtropica sp. nov., a thermophilic actinomycete isolated from soil of a sugar cane field.

A novel thermophilic actinomycete, designated strain T3T, was isolated from a soil sample of a sugar cane field. The strain grew at 25-60 °C (optimum 37-50 °C), at pH 6.0-11.0 (optimum 7.0-9.0) and with 0-12.0 % (w/v) NaCl (optimum 0-7 %). The aerial mycelium was white and the vegetative mycelium was colourless to pale yellow. The substrate mycelium fragmented into rod-shaped elements after 4-5 days at 50 °C. The aerial mycelium formed flexuous chains of 5-20 spores per chain; the oval-shaped spores had spiny surfaces and were non-motile. The organism contained meso-diaminopimelic acid as the diagnostic diamino acid in the cell-wall peptidoglycan. The whole-cell sugars consisted of arabinose, galactose and ribose. The cellular fatty acid profile consisted mainly of anteiso-C17 : 0, iso-C17 : 0 and iso-C16 : 0. The quinone system was composed predominantly of MK-9(H4). The phospholipids detected were diphosphatidylglycerol, phosphatidylcholine, phosphatidylinositol, phosphatidylethanolamine, phosphatidylmethylethanolamine and ninhydrin-positive glycophospholipids. The DNA G+C content of strain T3T was 71.3 mol%. The organism showed a combination of morphological and chemotaxonomic properties typical of members of the genus Saccharopolyspora. In the 16S rRNA gene tree of Saccharopolyspora it formed a distinct phyletic line and was related most closely to Saccharopolyspora thermophila 216T. However, the phenotypic characteristics of strain T3T were significantly different from those of S. thermophila 216T and DNA-DNA hybridization revealed a low level of relatedness (28.6-32.3 %) between them. Based on the phenotypic and phylogenetic data, strain T3T represents a novel species in the genus Saccharopolyspora, for which the name Saccharopolyspora subtropica sp. nov. is proposed. The type strain is T3T ( = DSM 46801T = CGMCC 4.7206T).

Unmasking the measles-like parchment discoloration: molecular and microanalytical approach.

Many ancient parchments are defaced by red or purple maculae associated with localized destruction of collagen fibres. Although the main characteristics of this damage were present in most of the manuscripts analysed by many authors, no common microbial or fungal denominator has been found so far, and little or no correspondence between the microbial or fungal species isolated from materials could be addressed. In this study, culture-independent molecular methods and scanning electron microscopy (SEM) were used to identify fungal and bacterial communities on parchments affected by the purple stains. Protocols for c extraction and nucleic-acid-based strategies were selected for assays examining the community structure of fungi and bacteria on biodeteriorated parchment. Both SEM and molecular analysis detected the presence of bacterial and fungal cells in the damaged areas. Halophilic, halotolerant proteolytic bacterial species were selected by the saline environment provided by the parchment samples. As common microbial denominators, members of the Actinobacteria, mainly Saccharopolyspora spp. and species of Aspergillus, were detected in all investigated cases. It is proposed that a relationship exists between the phenomenon of purple spots on ancient parchments and that of the 'red heat' phenomenon, known to be present in some products manufactured with marine salt.

Saccharopolyspora halotolerans sp. nov., a halophilic actinomycete isolated from a hypersaline lake.

A novel actinomycete strain, designated TRM 45123(T), was isolated from a hypersaline habitat in Xinjiang Province (40° 20' N 90° 49' E), north-west China. The isolate was characterized using a polyphasic approach. 16S rRNA gene sequence analysis indicated that strain TRM 45123(T) belonged to the genus Saccharopolyspora and was closely related to Saccharopolyspora gloriosae (96.7% similarity). The G+C content of the DNA was 69.07 mol%. The isolate contained meso-diaminopimelic acid as the diagnostic diamino acid, and arabinose and ribose as the major whole-cell sugars. The diagnostic phospholipids were phosphatidylethanolamine, phosphatidylcholine and phosphatidylglycerol. The predominant menaquinone was MK-9(H4). The major fatty acids were iso-C16 : 0, anteiso-C17:0, iso-C15:0 and anteiso-C15:0. On the basis of the evidence from this polyphasic study, a novel species, Saccharopolyspora halotolerans sp. nov., is proposed. The type strain of Saccharopolyspora halotolerans is TRM 45123(T) ( = CCTCC AA 2013006(T) = DSM 45990(T)).

SACE_3986, a TetR family transcriptional regulator, negatively controls erythromycin biosynthesis in Saccharopolyspora erythraea.

Erythromycin, a medically important antibiotic, is produced by Saccharopolyspora erythraea. Unusually, the erythromycin biosynthetic gene cluster lacks a regulatory gene, and the regulation of its biosynthesis remains largely unknown. In this study, through gene deletion, complementation and overexpression experiments, we identified a novel TetR family transcriptional regulator SACE_3986 negatively regulating erythromycin biosynthesis in S. erythraea A226. When SACE_3986 was further inactivated in an industrial strain WB, erythromycin A yield of the mutant was increased by 54.2 % in average compared with that of its parent strain, displaying the universality of SACE_3986 as a repressor for erythromycin production in S. erythraea. qRT-PCR analysis indicated that SACE_3986 repressed the transcription of its adjacent gene SACE_3985 (which encodes a short-chain dehydrogenase/reductase), erythromycin biosynthetic gene eryAI and the resistance gene ermE. As determined by EMSA analysis, purified SACE_3986 protein specifically bound to the intergenic region between SACE_3985 and SACE_3986, whereas it did not bind to the promoter regions of eryAI and ermE. Furthermore, overexpression of SACE_3985 in A226 led to enhanced erythromycin A yield by at least 32.6 %. These findings indicate that SACE_3986 is a negative regulator of erythromycin biosynthesis, and the adjacent gene SACE_3985 is one of its target genes. The present study provides a basis to increase erythromycin production by engineering of SACE_3986 and SACE_3985 in S. erythraea.

Saccharopolyspora ghardaiensis sp. nov., an extremely halophilic actinomycete isolated from Algerian Saharan soil.

A novel halophilic actinomycete, strain designated H53(T), was isolated from a Saharan soil sample collected from Chaâbet Ntissa, Béni-isguen, Ghardaïa (South of Algeria) and was characterized taxonomically by means of polyphasic approach. Optimal growth was found to occur at 30-35 °C, pH 6-7 and in the presence of 15-25% (w/v) NaCl. The strain was observed to produce abundant aerial mycelium, which formed long chains of rod-shaped spores at maturity, and well developed and fragmented substrate mycelium. The cell wall was determined to contain meso-diaminopimelic acid; the diagnostic whole-cell sugars were arabinose and galactose. The predominant menaquinones were found to be MK-9(H4) and MK-9(H6). The predominant cellular fatty acids were determined to be iso- and anteiso-C17:0, iso-C15:0, and cis9 iso-C17:1. The diagnostic phospholipid detected was phosphatidylcholine. The morphological and chemotaxonomic characteristics of the strain were consistent with those of members of the genus Saccharopolyspora. Phylogenetic analyses on the basis of the 16S ribosomal RNA (rRNA) gene sequence showed that this strain formed a distinct phyletic line within the radiation of the genus Saccharopolyspora. The 16S rRNA sequence similarities between strain H53(T) and other members of the genus Saccharopolyspora ranged from 92.1 to 94.3%. The DNA G+C content of strain H53(T) was 72.6%. The genotypic and phenotypic data showed that the strain H53(T) represents a novel species of the genus Saccharopolyspora, for which the name Saccharopolyspora ghardaiensis sp. nov. is proposed, with the type strain H53(T) (=DSM 45606(T)=CCUG 63370(T)=CECT 8304(T)).

Saccharopolyspora cavernae sp. nov., a novel actinomycete isolated from the Swallow Cave in Yunnan, south-west China.

A Gram-positive, aerobic, non-motile actinobacterial strain, designated YIM C01235(T), was isolated from a soil sample collected from the Swallow Cave, Yunnan province, south-west China. The isolate grew at 10-30 °C, pH 6.0-9.0 and 0-8 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences revealed highest similarity to Saccharopolyspora gloriosae YIM 60513(T) (96.8 %), and lower 16S rRNA gene sequence similarities (95.1-96.7 %) with the other species of the genus Saccharopolyspora. The whole-cell hydrolysates contained meso-diaminopimelic acid (meso-DAP), arabinose and galactose. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylmethylethanolamine, two unknown glycolipids, two unknown phospholipids and one polar lipid. MK-9(H4) was the predominant menaquinone. The major fatty acids were iso-C15:0, iso-C16:0, anteiso-C15:0 and anteiso-C17:0. Mycolic acids were not detected. The genomic DNA G+C content was 69.1 mol%. These chemotaxonomic data, together with its morphological properties, were consistent with the assignment of strain YIM C01235(T) to the genus Saccharopolyspora. The results of physiological and biochemical tests allowed strain YIM C01235(T) to be differentiated phenotypically from all the recognized Saccharopolyspora species. On the basis of evidence from this polyphasic study, the novel species Saccharopolyspora cavernae sp. nov. is proposed. The type strain is YIM C01235(T) (=DSM 45825(T) = CCTCC AA 2012022(T)).