A novel antimicrobial peptide S24 combats serious wound infections caused by Pseudomonas aeruginosa and Acinetobacter baumannii.

OBJECTIVES: Pseudomonas aeruginosa and Acinetobacter baumannii are ranked as top-priority organisms by WHO. Antimicrobial peptides (AMPs) are promising antimicrobial agents that are highly effective against serious bacterial infections. METHODS: In our previous study, a series of α-helical AMPs were screened using a novel multiple-descriptor strategy. The current research suggested that S24 exhibited strong antimicrobial activity against major pathogenic bacteria, and displayed minimal haemolysis, good serum stability and maintained salt resistance. RESULTS: We found that S24 exerted an antimicrobial effect by destroying outer membrane permeability and producing a strong binding effect on bacterial genomic DNA that inhibits genomic DNA migration. Furthermore, S24 exerted a strong ability to promote healing in wound infected by P. aeruginosa, A. baumannii and mixed strains in a mouse model. CONCLUSIONS: Overall, S24 showed good stability under physiological conditions and excellent antimicrobial activity, suggesting it may be a potential candidate for the development of serious bacterial infection treatment.

Associations of per- and polyfluoroalkyl substances (PFAS) and their mixture with risk of rheumatoid arthritis in the U.S. adult population.

BACKGROUND: Per- and polyfluoroalkyl substances (PFAS) are known environmental contaminants with immunosuppressive properties. Their connection to rheumatoid arthritis (RA), a condition influenced by the immune system, is not well studied. This research explores the association between PFAS exposure and RA prevalence. METHODS: This research utilized data from the NHANES, encompassing a sample of 10,496 adults from the 2003-2018 cycles, focusing on serum levels of several PFAS. The presence of RA was determined based on self-reports. This study used multivariable logistic regression to assess the relationship between individual PFAS and RA risk, adjusting for covariates to calculate odds ratios (ORs). The combined effects of PFAS mixtures were evaluated using BKMR, WQS regression, and quantile g-computation. Additionally, sex-specific associations were explored through stratified analysis. RESULTS: Higher serum PFOA (OR = 0.88, 95% CI: 0.79, 0.98), PFHxS (OR = 0.91, 95% CI: 0.83, 1.00), PFNA (OR = 0.87, 95% CI: 0.77, 0.98), and PFDA (OR = 0.89, 95% CI: 0.81, 0.99) concentration was related to lower odds of RA. Sex-specific analysis in single chemical models indicated the significant inverse associations were only evident in females. BKMR did not show an obvious pattern of RA estimates across PFAS mixture. The outcomes of sex-stratified quantile g-computation demonstrated that an increase in PFAS mixture was associated with a decreased odds of RA in females (OR: 0.76, 95% CI: 0.62, 0.92). We identified a significant interaction term of the WQS*sex in the 100 repeated hold out WQS analysis. Notably, a higher concentration of the PFAS mixture was significantly associated with reduced odds of RA in females (mean OR = 0.93, 95% CI: 0.88, 0.98). CONCLUSIONS: This study indicates potential sex-specific associations of exposure to various individual PFAS and their mixtures with RA. Notably, the observed inverse relationships were statistically significant in females but not in males. These findings contribute to the growing body of evidence indicating that PFAS may have immunosuppressive effects.

Biosynthesis Gene Cluster and Oxazole Ring Formation Enzyme for Inthomycins in Streptomyces sp. Strain SYP-A7193.

Inthomycins belong to a growing family of oxazole-containing polyketides and exhibit a broad spectrum of anti-oomycete and herbicidal activities. In this study, we purified inthomycins A and B from the metabolites of Streptomyces sp. strain SYP-A7193 and determined their chemical structures. Genome sequencing, comparative genomic analysis, and gene disruption of Streptomyces sp. SYP-A7193 showed that the inthomycin biosynthetic gene cluster (itm) belonged to the hybrid polyketide synthase (PKS)/nonribosomal peptide synthetase (NRPS) system. Functional domain comparison and disruption/complementation experiments of itm12 resulted in the complete loss of inthomycins A and B and the subsequent restoration of their production, confirming that itm12 encodes a discrete acyltransferase (AT), and hence, itm was considered to belong to the trans-AT type I PKS system. Moreover, the disruption/complementation experiments of itm15 also resulted in the loss and restoration of inthomycin A and B formation. Further gene cloning, expression, purification, and activity verification of itm15 revealed that Itm15 is a cyclodehydratase that catalyzes a straight-chain dehydration reaction to form an oxazole ring for the biosynthesis of inthomycins A and B. Thus, we discovered a novel enzyme that catalyzes oxazole ring formation and elucidated the complete biosynthetic pathway of inthomycins.IMPORTANCEStreptomyces species produce numerous secondary metabolites with diverse structures and pharmacological activities that are beneficial for human health and have several applications in agriculture. In this study, hybrid nonribosomal peptide synthetase/polyketide synthase metabolites inthomycins A and B were isolated from after fermenting Streptomyces sp. SYP-A7193. Genome sequencing, gene disruption, gene complementation, heterologous expression, and activity assay revealed that the biosynthesis gene assembly line of inthomycins A and B was a 95.3-kb trans-AT type I PKS system in the strain SYP-A7193. More importantly, Itm15, a cyclodehydratase, was identified to be an oxazole ring formation enzyme required for the biosynthesis of inthomycins A and B; it is significant to discover this catalyzation reaction in the PKS/NRPS system in the field of microbiology. Our findings could provide further insights into the diversity of trans-AT type I PKS systems and the mechanism of oxazole cyclization involved in the biosynthesis of natural products.

Insights into Streptomyces spp. isolated from the rhizospheric soil of Panax notoginseng: isolation, antimicrobial activity and biosynthetic potential for polyketides and non-ribosomal peptides.

BACKGROUND: Streptomycetes from the rhizospheric soils are a rich resource of novel secondary metabolites with various biological activities. However, there is still little information related to the isolation, antimicrobial activity and biosynthetic potential for polyketide and non-ribosomal peptide discovery associated with the rhizospheric streptomycetes of Panax notoginseng. Thus, the aims of the present study are to (i) identify culturable streptomycetes from the rhizospheric soil of P. notoginseng by 16S rRNA gene, (ii) evaluate the antimicrobial activities of isolates and analyze the biosynthetic gene encoding polyketide synthases (PKSs) and nonribosomal peptide synthetases (NRPSs) of isolates, (iii) detect the bioactive secondary metabolites from selected streptomycetes, (iv) study the influence of the selected isolate on the growth of P. notoginseng in the continuous cropping field. This study would provide a preliminary basis for the further discovery of the secondary metabolites from streptomycetes isolated from the rhizospheric soil of P. notoginseng and their further utilization for biocontrol of plants. RESULTS: A total of 42 strains representing 42 species of the genus Streptomyces were isolated from 12 rhizospheric soil samples in the cultivation field of P. notoginseng and were analyzed by 16S rRNA gene sequencing. Overall, 40 crude cell extracts out of 42 under two culture conditions showed antibacterial and antifungal activities. Also, the presence of biosynthesis genes encoding type I and II polyketide synthase (PKS I and PKS II) and nonribosomal peptide synthetases (NRPSs) in 42 strains were established. Based on characteristic chemical profiles screening by High Performance Liquid Chromatography-Diode Array Detector (HPLC-DAD), the secondary metabolite profiles of strain SYP-A7257 were evaluated by High Performance Liquid Chromatography-High Resolution Mass Spectrometry (HPLC-HRMS). Finally, four compounds actinomycin X2 (F1), fungichromin (F2), thailandin B (F7) and antifungalmycin (F8) were isolated from strain SYP-A7257 by using chromatography techniques, UV, HR-ESI-MS and NMR, and their antimicrobial activities against the test bacteria and fungus were also evaluated. In the farm experiments, Streptomyces sp. SYP-A7257 showed healthy growth promotion and survival rate improvement of P. notoginseng in the continuous cropping field. CONCLUSIONS: We demonstrated the P. notoginseng rhizospheric soil-derived Streptomyces spp. distribution and diversity with respect to their metabolic potential for polyketides and non-ribosomal peptides, as well as the presence of biosynthesis genes PKS I, PKS II and NRPSs. Our results showed that cultivatable Streptomyces isolates from the rhizospheric soils of P. notoginseng have the ability to produce bioactive secondary metabolites. The farm experiments suggested that the rhizospheric soil Streptomyces sp. SYP-A7257 may be a potential biological control agent for healthy growth promotion and survival rate improvement of P. notoginseng in the continuous cropping field.

Trichoderma panacis sp. nov., an endophyte isolated from Panax notoginseng.

An endophytic member of the genus Trichoderma was isolated from the root of a healthy 3-year-old Panax notoginseng in Yunnan province, PR China. The results of phylogenetic analyses based on a combined of ITS, tef1 and rpb2 indicated that this isolate was distinct from other species of the genus Trichoderma and closely related to Trichoderma songyi. It can be distinguished from T. songyi by its slower growth rates on PDA and colony morphology. The novel isolate formed conidia in thick white pustules scattered mostly at the margin. Its conidiophores tended to be regularly verticillium-like, little branched, sometimes substituted by phialides singly or in whorls. Conidia are smooth, mostly broadly subglobose to ellipsoidal. In combination with the genotypic and phenotypic characteristics, all data demonstrated that the fungus studied represented a unique and distinguishable novel species of the genus Trichoderma, for which the name Trichoderma panacis sp. nov. is proposed.

Peroxisome proliferator-activated receptor gamma participates in the acquisition of brain ischemic tolerance induced by ischemic preconditioning via glial glutamate transporter 1 in vivo and in vitro.

Glial glutamate transporter 1 (GLT-1) plays a vital role in the induction of brain ischemic tolerance (BIT) by ischemic preconditioning (IPC). However, the mechanism still needs to be further explained. The aim of this study was to investigate whether peroxisome proliferator-activated receptor gamma (PPARγ) participates in regulating GLT-1 during the acquisition of BIT induced by IPC. Initially, cerebral IPC induced BIT and enhanced PPARγ and GLT-1 expression in the CA1 hippocampus in rats. The ratio of nuclear/cytoplasmic PPARγ was also increased. At the same time, the up-regulation of PPARγ expression in astrocytes in the CA1 hippocampus was revealed by double immunofluorescence for PPARγ and glial fibrillary acidic protein. Then, the mechanism by which PPARγ regulates GLT-1 was studied in rat cortical astrocyte-neuron cocultures. We found that IPC [45 min of oxygen glucose deprivation (OGD)] protected neuronal survival after lethal OGD (4 h of OGD), which usually leads to neuronal death. The activation of PPARγ occurred earlier than the up-regulation of GLT-1 in astrocytes after IPC, as determined by western blot and immunofluorescence. Moreover, the preadministration of the PPARγ antagonist T0070907 or PPARγ siRNA significantly attenuated GLT-1 up-regulation and the neuroprotective effects induced by IPC in vitro. Finally, the effect of the PPARγ antagonist on GLT-1 expression and BIT was verified in vivo. We observed that the preadministration of T0070907 by intracerebroventricular injection dose-dependently attenuated the up-regulation of GLT-1 and BIT induced by cerebral IPC in rats. In conclusion, PPARγ participates in regulating GLT-1 during the acquisition of BIT induced by IPC. Cover Image for this issue: doi: 10.1111/jnc.14532. Open Science: This manuscript was awarded with the Open Materials Badge For more information see: https://cos.io/our-services/open-science-badges/.

Nitric Oxide Participates in the Brain Ischemic Tolerance Induced by Intermittent Hypobaric Hypoxia in the Hippocampal CA1 Subfield in Rats.

Previous studies have shown that intermittent hypobaric hypoxia (IH) preconditioning protected neurons survival from brain ischemia. However, the mechanism remains to be elucidated. The present study explored the role of nitric oxide (NO) in the process by measuring the expression of NO synthase (NOS) and NO levels. Male Wistar rats (100) were randomly assigned into four groups: sham group, IH + sham group, ischemia group and IH + ischemia group. Rats for IH preconditioning were exposed to hypobaric hypoxia mimicking 5000 m high-altitude (PB = 404 mmHg, PO2 = 84 mmHg) 6 h/day, once daily for 28 days. Global brain ischemia was established by four-vessel occlusion that has been created by Pulsinelli. Rats were sacrificed at 7th day after the ischemia for neuropathological evaluation by thionin stain. In addition, the expression of neuronal NOS (nNOS), inducible NOS (iNOS), and NO content in the hippocampal CA1 subfield were measured at 2nd day and 7th day after the ischemia. Results revealed that global brain ischemia engendered delayed neuronal death (DND), both nNOS and iNOS expression up-regulated, and NO content increased in the hippocampal CA1 subfield. IH preconditioning reduced neuronal injury induced by the ischemia, and prevented the up-regulation of NOS expression and NO production. In addition, L-NAME + ischemia group was designed to detect whether depressing NO production could alleviate the DND. Pre-administration of L-NAME alleviated DND induced by the ischemia. These results suggest that IH preconditioning plays a protective role by inhibiting the over expression of NOS and NO content after brain ischemia.

Correction to: Nitric Oxide Participates in the Brain Ischemic Tolerance Induced by Intermittent Hypobaric Hypoxia in the Hippocampal CA1 Subfield in Rats.

The order of corresponding author was inadvertently published. Hence, the first and the second corresponding authors should be Min Zhang (hebmuzhangmin@163.com) and Jing-Ge Zhang (zhangjg001@163.com).

Flavobacterium artemisiae sp. nov., isolated from the rhizosphere of Artemisia annua L. and emended descriptions of Flavobacterium compostarboris and Flavobacterium procerum.

A Gram-stain-negative, strictly aerobic, yellow-coloured, motile by gliding and elongated rod-shaped bacterial strain, designated SYP-B1015T, was isolated from the rhizosphere of Artemisia annua L. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain SYP-B1015T belonged to the genus Flavobacterium and had highest 16S rRNA gene sequence similarity to Flavobacterium compostarboris JCM 16527T (98.1 %) and Flavobacterium procerum JCM 30113T (97.2 %). The predominant respiratory quinone for the strain was MK-6, and the major cellular fatty acids were iso-C15 : 0, iso-C15 : 0 3-OH and iso-C17 : 0 3-OH. The polar lipid profile contained phosphatidylethanolamine as a major compound. The DNA G+C content of strain SYP-B1015T was 33.5 mol%. The DNA-DNA relatedness values between strain SYP-B1015T and F. compostarboris JCM 16527T and F. procerum JCM 30113T were 56.5±0.4 and 48.9±1.2 %, respectively. Combining the data from morphological, physiological, biochemical and chemotaxonomic characterizations presented in this study, strain SYP-B1015T represents a novel species of the genus Flavobacterium, for which the name Flavobacterium artemisiae sp. nov. is proposed. The type strain is SYP-B1015T (=CGMCC 1.16115T=KCTC 62025T).

Verruconis panacis sp. nov., an endophyte isolated from Panax notoginseng.

An endophytic strain (designated as strain SYPF 8337T) was isolated from the root of 3-year-old Panax notoginseng in Yunnan province of China. Strain SYPF 8337T grew slowly and formed pale brown to brown colonies. Phylogenetic analyses indicated that strain SYPF 8337T was placed in the Verruconis clade. Different from other Verruconis species, strain SYPF 8337T produced four-cell conidia. Furthermore, strain SYPF 8337T is the first fungus isolated as an endophyte of P. notoginseng in the genus Verruconis. Combined with the morphology and molecular analyses, a new species named Verruconis panacis sp. nov. is proposed.

Drechmeria panacis sp. nov., an endophyte isolated from Panax notoginseng.

An endophytic strain (designated as strain SYPF 8335T) was isolated from a root of Panax notoginseng in Wenshan district, Yunnan province of China. Strain SYPF 8335T grew very slowly and formed white colonies. Phylogenetic analysis of four loci indicated that strain SYPF 8335T was placed in the Drechmeria clade with Drechmeria campanulata as its closest phylogenetic neighbour. The nucleotide differences between strain SYPF 8335T and D. campanulata are 30 substitutions in the internal transcriber region region. A key morphological feature that differentiates the two fungi is that D. campanulata produces campanulate conidia. Combined with the morphology and molecular analyses, a new species named Drechmeria panacis sp. nov., is proposed.

Absidia panacisoli sp. nov., isolated from rhizosphere of Panax notoginseng.

A strain (SYPF 7183T) was isolated from rhizosphere soil of Panax notoginseng in southwest China. Phylogenetic analyses indicated that strain SYPF 7183T was distinct from the other Absidia species with well-supported values. Strain SYPF 7183T produced spherical or subpyriform sporangia and short cylindrical sporangiospores. The azygospores were globose to oval. Based on morphological and phylogenetic evidence, the novel strain Absidia panacisoli sp. nov. is proposed.

Establishing an innovative carbohydrate metabolic pathway for efficient production of 2-keto-L-gulonic acid in Ketogulonicigenium robustum initiated by intronic promoters.

BACKGROUND: 2-Keto-L-gulonic acid (2-KGA), the precursor of vitamin C, is currently produced by two-step fermentation. In the second step, L-sorbose is transformed into 2-KGA by the symbiosis system composed of Ketogulonicigenium vulgare and Bacillus megaterium. Due to the different nutrient requirements and the uncertain ratio of the two strains, the symbiosis system significantly limits strain improvement and fermentation optimization. RESULTS: In this study, Ketogulonicigenium robustum SPU_B003 was reported for its capability to grow well independently and to produce more 2-KGA than that of K. vulgare in a mono-culture system. The complete genome of K. robustum SPU_B003 was sequenced, and the metabolic characteristics were analyzed. Compared to the four reported K. vulgare genomes, K. robustum SPU_B003 contained more tRNAs, rRNAs, NAD and NADP biosynthetic genes, as well as regulation- and cell signaling-related genes. Moreover, the amino acid biosynthesis pathways were more complete. Two species-specific internal promoters, P1 (orf_01408 promoter) and P2 (orf_02221 promoter), were predicted and validated by detecting their initiation activity. To efficiently produce 2-KGA with decreased CO2 release, an innovative acetyl-CoA biosynthetic pathway (XFP-PTA pathway) was introduced into K. robustum SPU_B003 by expressing heterologous phosphoketolase (xfp) and phosphotransacetylase (pta) initiated by internal promoters. After gene optimization, the recombinant strain K. robustum/pBBR-P1_xfp2502-P2_pta2145 enhanced acetyl-CoA approximately 2.4-fold and increased 2-KGA production by 22.27% compared to the control strain K. robustum/pBBR1MCS-2. Accordingly, the transcriptional level of the 6-phosphogluconate dehydrogenase (pgd) and pyruvate dehydrogenase genes (pdh) decreased by 24.33 ± 6.67 and 8.67 ± 5.51%, respectively. The key genes responsible for 2-KGA biosynthesis, sorbose dehydrogenase gene (sdh) and sorbosone dehydrogenase gene (sndh), were up-regulated to different degrees in the recombinant strain. CONCLUSIONS: The genome-based functional analysis of K. robustum SPU_B003 provided a new understanding of the specific metabolic characteristics. The new XFP-PTA pathway was an efficient route to enhance acetyl-CoA levels and to therefore promote 2-KGA production.

Drechmerin H, a novel 1(2), 2(18)-diseco indole diterpenoid from the fungus Drechmeria sp. as a natural agonist of human pregnane X receptor.

A novel 1(2), 2(18)-diseco indole diterpenoid, drechmerin H (1), was isolated from the fermentation broth of Drechmeria sp. together with a new indole diterpenoid, 2'-epi terpendole A (3), and a known analogue, terpendole A (2). Their structures were determined by HRESIMS, 1D and 2D NMR, ECD, and X-ray single crystal diffraction analyses as well as quantum chemical calculation. The abosulte configuration of terpendole A (2) was determined for the first time. Compound 1 displayed the significant agonistic effect on pregnane X receptor (PXR) with EC50 value of 134.91 ±â€¯2.01 nM, and its interaction with PXR was investigated by molecular docking. Meantime, a plausible biosynthetic pathway for compounds 1-3 is also discussed in the present work.

A novel pigmented and heavy metal biosorptive bacterium, Leucobacter epilobiisoli sp. nov., isolated from rhizosphere soil of Epilobium hirsutum L.

A novel yellow pigmented, Gram-positive, aerobic and heavy metal biosorptive bacterium designated SYP-B2667T was isolated from rhizosphere soil of Epilobium hirsutum L. in Tongren, Guizhou province, China. Based on 16S rRNA gene sequence analyses, it was shown that strain SYP-B2667T represents a novel species in the genus Leucobacter, with Leucobacter chromiireducens subsp. solipictus JCM 15573T as a close phylogenetic neighbour (sequence similarity of 98.2%). Chemotaxonomic characteristics also supported the affiliation to the genus Leucobacter. Strain SYP-B2667T was determined to have a DNA G+C content of 66.6 mol%; 2,4-diaminobutyric acid in the cell wall peptidoglycan amino acids; MK-11 as predominant menaquinone; an abundance of anteiso-C15:0 and anteiso-C17:0 fatty acids; and polar lipids including diphosphatidylglycerol, phosphatidylglycerol, glycolipids and unidentified phospholipids. The DNA-DNA hybridization value between strain SYP-B2667T and L. chromiireducens subsp. solipictus JCM 15573T was 19.7 ± 2.8%. Based on these phylogenetic and phenotypic results, it can be concluded that strain SYP-B2667T represents a novel species, for which the name Leucobacter epilobiisoli sp. nov. is proposed. The type strain is SYP-B2667T (=DSM 105145T=CPCC 204976T). This strain can tolerate and adsorb five heavy metals and so may have potential to facilitate heavy metal removal and bioremediation.

A novel method of multiple nucleic acid detection: Real-time RT-PCR coupled with probe-melting curve analysis.

A novel method, real-time reverse transcription PCR (real-time RT-PCR) coupled with probe-melting curve analysis, has been established to detect two kinds of samples within one fluorescence channel. Besides a conventional TaqMan probe, this method employs another specially designed melting-probe with a 5' terminus modification which meets the same label with the same fluorescent group. By using an asymmetric PCR method, the melting-probe is able to detect an extra sample in the melting stage effectively while it almost has little influence on the amplification detection. Thus, this method allows the availability of united employment of both amplification stage and melting stage for detecting samples in one reaction. The further demonstration by simultaneous detection of human immunodeficiency virus (HIV) and hepatitis C virus (HCV) in one channel as a model system is presented in this essay. The sensitivity of detection by real-time RT-PCR coupled with probe-melting analysis was proved to be equal to that detected by conventional real-time RT-PCR. Because real-time RT-PCR coupled with probe-melting analysis can double the detection throughputs within one fluorescence channel, it is expected to be a good solution for the problem of low-throughput in current real-time PCR.

Development of a paper-based microfluidic analytical device by a more facile hydrophobic substrate generation strategy.

Microfluidic paper-based analytical devices (µPADs) have a significant potential in developing portable and disposable point-of-care testing (POCT). Herein, a facile, rapid, cost-effective and environment friendly strategy for µPADs fabrication is proposed. Specifically, the substrate paper was hydrophobized by coating with trimethoxysilane (TOS), and then the selected area was hydrophilized by treating with surfactant. The whole fabrication process was implemented within 7 min, with no need for complex pre-treatment, high-temperature and special equipment. As a proof-of-concept application, the as-prepared µPAD was applied to determination of the glucose content in human serum samples. The results agreed well with those obtained by a glucometer. We believe that the µPADs fabrication method proposed here could provide a facile, rapid and low-cost reference for other related studies.

Bacillus notoginsengisoli sp. nov., a novel bacterium isolated from the rhizosphere of Panax notoginseng.

A Gram-stain-positive, rod-shaped, motile bacterium designated as SYP-B691T was isolated from rhizospheric soil of Panax notoginseng. Phylogenetic analysis indicated that SYP-B691T clearly represented a member of the genus Bacillus and showed 16S rRNA gene similarity lower than 97.0 % with the type strains of species of the genus Bacillus, which indicates that it should be considered as a candidate novel species within this genus. The optimum growth of the strain was found to occur at 37 °C and pH 7.0-9.0. The genomic DNA G+C content was determined to be 45.2 mol%. It contained meso-2,6-diaminopimelic acid in the cell-wall peptidoglycan. The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and an unknown phospholipid. MK-7 was the only menaquinone identified. The major cellular fatty acids of SYP-B691T were identified as iso-C15 : 0 and anteiso-C15 : 0. On the basis of phenotypic, chemotaxonomic and phylogenetic characteristics, SYP-B691T merits recognition as a representative of a novel species of the genus Bacillus, for which the name Bacillus notoginsengisoli sp. nov. is proposed, with SYP-B691T(=DSM 29196T=JCM 30743T) as the type strain.

Arthrobacter ginkgonis sp. nov., an actinomycete isolated from rhizosphere of Ginkgo biloba L.

A Gram-stain-positive, aerobic actinobacterial strain (designated SYP-A7299T), which displayed a rod-coccus growth lifecycle, was isolated from the rhizosphere of Ginkgo biloba L. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain SYP-A7299T belongs to the genus Arthrobacter and is most closely related to Arthrobacter halodurans JSM 078085T (97.4 % 16S rRNA gene sequence similarity). The DNA-DNA relatedness value between strain SYP-A7299T and A. halodurans JSM 078085T was 37 % ±2.9. The cell-wall peptidoglycan was A4α, and glucose and galactose were whole-cell sugars. The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, two glycolipids and an unknown polar lipid. The major menaquinone were MK-8(H2) (72 %) and MK-9(H2) (28 %), and the predominant cellular fatty acids were anteiso-C15 : 0, iso-C15 : 0 and anteiso-C17 : 0. The DNA G+C content was 68.9 mol%. Based on the morphological, physiological, biochemical and chemotaxonomic characters presented in this study, strain SYP-A7299T represents a novel species of the genus Arthrobacter, for which the name Arthrobacter ginkgonis sp. nov. is proposed. The type strain is SYP-A7299T (=DSM 100491T=KCTC 39 592T).

Nocardioides ginkgobilobae sp. nov., an endophytic actinobacterium isolated from the root of the living fossil Ginkgo biloba L.

A Gram-stain-positive, aerobic and yellow actinobacterial strain, designated SYP-A7303T, was isolated from the root of Ginkgo biloba L. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain SYP-A7303T belongs to the genus Nocardioides. The 16S rRNA gene sequence of strain SYP-A7303T showed highest similarity to Nocardioides marinus CL-DD14T ( = JCM 15615T) (98.3 %) and Nocardioides aquiterrae GW-9T ( = JCM 11813T) (97.1 %), and less than 96.9 % to the type strains of other species of the genus Nocardioides. Strain SYP-A7303T grew optimally at 28 °C, pH 7.0 and in the absence of NaCl. It contained ll-2,6-diaminopimelic acid in the cell-wall peptidoglycan, with mannose, ribose, rhamnose, glucose and galactose as whole-cell sugars. The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and an unknown lipid. The menaquinone was MK-8(H4) and the predominant cellular fatty acids were iso-C16 : 0, C18 : 1ω9c and C17 : 1ω8c. The DNA G+C content was 72 mol%. Mean DNA-DNA relatedness values between strain SYP-A7303T and the closely related strains N. marinus JCM 15615T and N. aquiterrae JCM 11813T were 62.5 ± 2.4 and 56.5 ± 3.5 %, respectively. Based on the morphological, physiological, biochemical and chemotaxonomic characteristics presented in this study, strain SYP-A7303T represents a novel species of the genus Nocardioides, for which the name Nocardioides ginkgobilobae sp. nov. is proposed. The type strain is SYP-A7303T ( = DSM 100492T = KCTC 39594T).