Rapid detection and quantification of adulteration in saffron by excitation-emission matrix fluorescence combined with multi-way chemometrics.

BACKGROUND: Saffron has gained people's attention and love for its unique flavor and valuable edible value, but the problem of saffron adulteration in the market is serious. It is urgent for us to find a simple and rapid identification and quantitative estimation of adulteration in saffron. Therefore, excitation-emission matrix (EEM) fluorescence combined with multi-way chemometrics was proposed for the detection and quantification of adulteration in saffron. RESULTS: The fluorescence composition analysis of saffron and saffron adulterants (safflower, marigold and madder) were accomplished by alternating trilinear decomposition (ATLD) algorithm. ATLD and two-dimensional principal component analysis combined with k-nearest neighbor (ATLD-kNN and 2DPCA-kNN) and ATLD combined with data-driven soft independent modeling of class analogies (ATLD-DD-SIMCA) were applied to rapid detection of adulteration in saffron. 2DPCA-kNN and ATLD-DD-SIMCA methods were adopted for the classification of chemical EEM data, first with 100% correct classification rate. The content of adulteration of adulterated saffron was predicted by the N-way partial least squares regression (N-PLS) algorithm. In addition, new samples were correctly classified and the adulteration level in adulterated saffron was estimated semi-quantitatively, which verifies the reliability of these models. CONCLUSION: ATLD-DD-SIMCA and 2DPCA-kNN are recommended methods for the classification of pure saffron and adulterated saffron. The N-PLS algorithm shows potential in prediction of adulteration levels. These methods are expected to solve more complex problems in food authenticity. © 2023 Society of Chemical Industry.

Haloterrigena gelatinilytica sp. nov., a new extremely halophilic archaeon isolated from salt-lake.

Two extremely halophilic strains, designated SYSU A558-1T and SYSU A121-1, were isolated from a saline sediment sample collected from Aiding salt-lake, China. Cells of strains SYSU A558-1T and SYSU A121-1 were Gram-stain-negative, coccoid, and non-motile. The strains were aerobic and grew at NaCl concentration of 10-30% (optimum, 20-22%), at 20-55 °C (optimum, 37-42 °C) and at pH 6.5-8.5 (optimum, 7.0-8.0). Cells lysed in distilled water. The polar lipids were phosphatidyl choline, phosphatidylglycerol phosphate methyl ester, disulfated diglycosyl diether-1 and unidentified glycolipid. Phylogenetic analysis based on the 16S rRNA gene sequence revealed that the two strains SYSU A558-1T and SYSU A121-1 were closely related to the membranes of the genus Haloterrigena. Phylogenetic and phylogenomic trees of strains SYSU A558-1T and SYSU A121-1 demonstrated a robust clade with Haloterrigena turkmenica, Haloterrigena salifodinae and Haloterrigena salina. The genomic DNA G + C content of strains SYSU A558-1T and SYSU A121-1 were 65.8 and 65.0%, respectively. Phenotypic, phylogenetic, chemotaxonomic and genome analysis suggested that the two strains SYSU A558-1T and SYSU A121-1 represent a novel species of the genus Haloterrigena, for which the name Haloterrigena gelatinilytica sp. nov. is proposed. The type strain is SYSU A558-1T (= KCTC 4259T = CGMCC 1.15953T).

Metagenomic analysis further extends the role of Chloroflexi in fundamental biogeochemical cycles.

Chloroflexi members are ubiquitous and have been extensively studied; however, the evolution and metabolic pathways of Chloroflexi members have long been debated. In the present study, the evolution and the metabolic potentials of 17 newly obtained Chloroflexi metagenome-assembled genomes (MAGs) were evaluated using genome and horizontal gene transfer (HGT) analysis. Taxonomic analysis suggests that the MAGs of the present study might be novel. One MAG encodes genes for anoxygenic phototrophy. The HGT analysis suggest that genes responsible for anoxygenic phototrophy in the MAG might have been transferred from Proteobacteria/Chlorobi. The evolution of anaerobic photosynthesis, which has long been questioned, has now been shown to be the result of HGT events. An incomplete Wood-Ljungdahl pathway (with missing genes metF, acsE, fdh, and acsA) was reported in Dehalococcoidetes members. In the present study, MAGs that were not the Dehalococcoidetes members encode genes acsA, acsB, metF and acsE. The genes responsible for sulfate reduction (sat, cysC and sir), dissimilatory sulfite reductase (dsrA and dsrB), and aerobic and anaerobic carbon monoxide oxidation (coxSML and cooSF) were detected in the present study MAGs. The present study expands our knowledge of the possible metabolic potentials of the phylum Chloroflexi and clarifies the evolution of anaerobic photosynthesis.

[Preparation of monoclonal antibodies against Pinellia ternata lectin protein and establishment of double-antibody sandwich ELISA].

To determine the content of endogenous toxic substance Pinellia ternata lectin(PTL) protein in Pinelliae Rhizoma and the related processed products, this study prepared specific monoclonal antibodies against PTL by hybridoma cell technology, and established a quantitative double-antibody sandwich enzyme linked immunosorbent assay(ELISA) for PTL antigen. The detection conditions were 2.5 µg·mL~(-1) working concentration of the captured antibody and 1∶450 of the dilution multiple of detected antibody. The coating condition was staying overnight at 4 ℃. The blocking time and incubation times of antigen and detected antibody were all 90 minutes. The incubation time of horseradish peroxidase conjugated streptavidin-horseradish peroxidase(SA-HRP) was 15 minutes. The quantitative limit of the method for PTL antigen was 0.375 ng·mL~(-1). The linear range was 75.000-4 800.000 pg·mL~(-1), and R~2=0.997 1. The recovery rate was 90.0%-110.0%, and the variation coefficients of intra-test and inter-test precision were 2.0%-3.0% and 2.0%-8.5%.The content of PTL in three batches of Pinelliae Rhizoma and the related processed products was determined by the method, and the average content of PTL in Pinelliae Rhizoma was 35.42 mg·g~(-1). The average content of PTL in Pinelliae Rhizoma Praeparatum Cum Alumine, Pinelliae Rhizoma Praeparatum, and Pinelliae Rhizoma Praeparatum Cum Zingibere Et Alumine were 1.15 mg·g~(-1), 16.53 µg·g~(-1), and 122.63 ng·g~(-1), respectively, indicating that the content of PTL decreased significantly after processing. The quantitative double-antibody sandwich ELISA for PTL antigen established in this paper had good linearity, sensitive response, and high accuracy, which provided a simple and effective monitoring method for the detection of PTL content in the processing of Pinelliae Rhizoma.

[Irritant toxicity and lectin content of different processed products of Pinelliae Rhizoma].

The present study aims to investigate the correlation between irritant toxicity variation and lectin content variation during the processing of Pinelliae Rhizoma products and to explore the feasibility of Western blot as a method for the detection of lectin. We processed Pinelliae Rhizoma Praeparatum Cum Alumine, Pinelliae Rhizoma Praeparatum, and Pinelliae Rhizoma Praeparatumcum Zingibere et Alumine to different degrees and then analyzed their irritant toxicity via Draize rabbit eye test. Western blot was employed to determine the lectin content in Pinelliae Rhizoma products processed with different methods. The correlation between toxicity variation and lectin content variation was then analyzed. Different decoction pieces of Pinelliae Rhizoma were collected for the determination of lectin content. The three processed products of Pinelliae Rhizoma showed gradually decreased toxicity and lectin content as the processing continued. The decreasing trend of lectin content was consistent with that of irritant toxicity during processing, which indicated that the change in lectin content could reflect the trend of irritant toxicity. No band of lectin appeared in the Western blot of processed products of Pinelliae Rhizoma, which suggested that western blotting can be used for the detection of toxic lectin in the processed products of Pinelliae Rhizoma. Lectin should not be detected in the Pinelliae Rhizoma products processed according to the methods in the Chinese Pharmacopoeia.

[Simulated processing with vinegar changes chemical structures of main terpenoids in Euphorbiae Ebracteolatae Radix].

This study aims to explore the chemical structure transformation mechanisms of the main terpenoids in the effective fraction of Euphorbiae Ebracteolatae Radix(EER) during the processing with vinegar. The terpenoids including ent-11α-hydroxyabicta-8(14),13(15)-dien-16,12-olide(HAO), jolkinolide B(JNB), fischeria A(FA), and eupractenoid A(EA) were heated at 160 ℃ with 6% acetic acid for 40 min, and then LC-MS/MS was employed to analyze the structural transformation rules of the terpenoids. Further, we analyzed the changes in the relative content of the four compounds and their transformation products in raw and vinegar processed EER to verify the transformation rules during the simulated processing with vinegar. In addition, JNB and FA were processed with single heating, heating with water or heating with acetic acid. We then employed HPLC to compare the content of these two terpenoids and their transformation products before and after processing, so as to investigate the effect of different processing methods on chemical structure transformation. The results showed that the lactone ring of the abietane-type diterpenoids HAO and JNB and the norditerpene lactone FA were opened by heating with acetic acid. When there were hydroxyl groups in the structures, terpenoids were esterized to esters and oxidized to form carbonyl groups. When there was epoxy ring in the structures, ring opening reaction was easy to occur. During the heating with acetic acid, the heterodimeric diterpenoid EA underwent the cleavage of ether bond to produce the rosane-type diterpenoid euphebracteolatin A(EHTA) and another abietane-type diterpenoid. The changes in the relative content of terpenoids and their transformation products in raw and vinegar-processed EER were basically consistent with those of simulated processing of components with vinegar. The HPLC results revealed that the effect of different simulated processing methods on structural transformation varied. Heating with acid can change JNB and FA into new components. Heating with water can also promote the structural transformation, with the efficiency obviously lower than that of heating with acid. Direct heating had no influence on the structure of JNB, while it significantly reduced the relative content of FA. The components treated with direct heating did not produce the products like those of the heating with acid. These results indicated that vinegar plays a key role in the structural transformation of diterpenoids during the processing of EER with vinegar. The structural transformation of diterpenoids in EER during the processing with vinegar may be the material basis for vinegar processed EER to reduce toxicity and preserve effect.

Haloechinothrix aidingensis sp. nov., an actinomycete isolated from salt lake in Xinjiang province, north-west China.

An actinomycete strain, designated YIM 98757T, was isolated from the hypersaline sediment of Aiding Lake in Xinjiang province, north-west China. The strain grew well on most media tested and no diffusible pigment was produced. The substrate mycelium was well developed and fragmented. No spores were formed. The whole-cell hydrolysates contained meso-diaminopimelic acid as the cell-wall diamino acid. Xylose, galactose, ribose were the major whole-cell sugars. The phospholipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol mannosides and an unknown phospholipid. The predominant menaquinone was MK-8(H4). The major fatty acid was iso-C16:0. The DNA G + C content was 69.1 mol%. Phylogenetic analysis indicated that the isolate belongs to the genus Haloechinothrix. However, it differed from its closest relative, H. alba YIM 98757 T in many phenotypic and chemotaxonomic characteristics. Moreover, the DNA-DNA and ANI relatedness values between the novel isolate and H. alba YIM 93221 T were 53.3% and 92.5%, respectively. Based on comparative analysis of polyphasic taxonomic data, strain YIM 98757 T represents a novel species of the genus Haloechinothrix, for which the name Haloechinothrix aidingensis sp. nov. is proposed. The type strain is YIM 98757T (= CGMCC 4.7627T = CCTCC AA 2020012).

Gulosibacter sediminis sp. nov., isolated from Indian Ocean marine sediment.

A novel Gram-stain-positive, catalase-positive, oxidase-negative, aerobic, non-motile, rod-shaped bacterium, designated strain YIM M12148T, was isolated from a marine sediment sample collected from the Indian Ocean. The strain grew optimally at 28 °C, pH 8.0 and in the presence of 1-3 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain YIM M12148T belongs to the genus Gulosibacter, with the highest sequence similarity to Gulosibacter faecalis NBRC 15706T (96.12 %). The cell-wall sugars of strain YIM M12148T were rhamnose, ribose, glucose and mannose. The predominant isoprenoid quinones were MK-8 and MK-9. The polar lipids consisted of major amounts of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, one unknown phospholipid and one unknown lipid. Major fatty acids (>5 % of the total) of the novel isolate were anteiso-C15 : 0, iso-C15 : 0, iso-C13 : 0 and anteiso-C13 : 0. The genomic DNA G+C content of strain YIM M12148T was 67.15 mol%. On the basis of genotypic and phenotypic data, it is apparent that strain YIM M12148T represents a novel species of the genus Gulosibacter, for which the name Gulosibacter sediminis sp. nov. is proposed. The type strain is YIM M12148T (=KCTC 29660T=DSM 29154T).

Brachybacterium subflavum sp. nov., a novel actinobacterium isolated from the foregut of grass carp.

A novel actinobacterium, designated CFH 10395T, was isolated from the foregut of grass carp (Ctenopharyngodon idella), which had been fed with ginseng extract supplement. The taxonomic position was investigated by a polyphasic approach. Cells of CFH 10395T were Gram-staining-positive, aerobic, ovoid-shaped, non-spore-forming and non-motile. On the basis of the results of 16S rRNA gene sequence analysis, CFH 10395T was most closely related to Brachybacterium endophyticum KCTC 49087T, Brachybacterium squillarum JCM 16464T and Brachybacterium paraconglomeratum JCM 17781T (97.85%, 97.51 and 97.29% similarity, respectively). CFH 10395T grew at 4-37 °C, pH 5.0-9.0 and in the presence of up to 10.0 % NaCl (w/v). The dominant menaquinone was MK-7. The whole-cell sugars were rhamnose, glucose, mannose and galactose. meso-diaminopimelic acid was the diagnostic diamino acid in the cell-wall peptidoglycan. The major fatty acids were anteiso-C15 : 0, anteiso-C17 : 0 and iso-C16 : 0. The genome size was 3.99 Mbp with a DNA G+C content of 71.9 mol%. On the basis of the results of phylogenetic analysis, physiological properties, chemotaxonomic characteristics, low average nucleotide identity (ANI) and digital DDH (dDDH) results [ANI calculated using MUMmer (ANIm) <87 %, ANI calculated using blast (ANIb) <83 % and dDDH <23 %], it is concluded that CFH 10395T represents a novel species of the genus Brachybacterium, for which the name Brachybacterium subflavum sp. nov., is proposed. The type strain is CFH 10395T (=CGMCC 1.13804T=KCTC 49235T).

Halegenticoccus tardaugens sp. nov., an extremely halophilic archaeon isolated from a saline soil.

Two extremely halophilic archaea, isolates SYSU A00711T and SYSU A00630, were isolated from a sediment soil sample collected from the Aiding lake, China. Cells of these isolates were cocci, non-motile and stained Gram-negative. They grew optimally at 37 °C, with 20-22% NaCl (w/v) and at pH 7.5-8.0. Cells lysed in distilled water. Major polar lipids were phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, mannosyl glucosyl diether, sulfated mannosyl glucosyl diether, and two unidentified glycolipids. Pairwise sequence comparison revealed that isolates SYSU A00711T and SYSU A00630 were closely related to Halegenticoccus soli SYSU A9-0T (94.1 and 94.0% 16S rRNA gene sequence similarities; 94.0 and 94.2% rpoB' gene similarities, respectively). The overall genomic relatedness indices values between the two isolates and Halegenticocus soli SYSU A9-0 T were: AAI, both 79.6%; ANI, 84.6 and 84.5%; dDDH, 32.5 and 26.3%, respectively. Phylogenetic trees based on the 16S rRNA gene, rpoB' gene, and genome sequences demonstrated a robust clade of these two isolates with Halegenticoccus soli SYSU A9-0T. The DNA G + C contents of these two isolates are both 64.7% (genome method). Based on the differences in phenotypic, chemotaxonomic, and phylogenetic properties, isolates SYSU A00711T and SYSU A00630 are characterized to represent a novel species in the genus Halegenticoccus, for which the name Halegenticoccus tardaugens sp. nov. is proposed. The type strain of the species Halegenticoccus tardaugens is SYSU A00711T (= KCTC 4245T = CGMCC 1.15768T).

Transcriptomic responses of haloalkalitolerant bacterium Egicoccus halophilus EGI 80432T to highly alkaline stress.

The haloalkalitolerant bacterium Egicoccus halophilus EGI 80432T exhibits high adaptability to saline-alkaline environment. The salinity adaptation mechanism of E. halophilus EGI 80432T was fully understood based on transcriptome analyses and physiological responses; however, the alkaline response mechanism has not yet been investigated. Here, we investigated the alkaline response mechanism of E. halophilus EGI 80432T by a transcriptomic comparison. In this study, the genes involved in the glycolysis, TCA cycle, starch, and trehalose metabolism for energy production and storage, were up-regulated under highly alkaline condition. Furthermore, genes responsible for the production of acidic and neutral metabolites, i.e., acetate, pyruvate, formate, glutamate, threonine, and ectoine, showed increased expression under highly alkaline condition, compared with the control pH condition. In contrast, the opposite results were observed in proton capture or retention gene expression profiles, i.e., cation/proton antiporters and ATP synthases. The above results revealed that E. halophilus EGI 80432T likely tended to adopt an "acidic metabolites production" strategy in response to a highly alkaline condition. These findings would pave the way for further studies in the saline-alkaline adaptation mechanisms of E. halophilus EGI 80432T, and hopefully provide a new insight into the foundational theory and application in ecological restoration with saline-alkaline strains.

Correction to: Description of Paenibacillus yunnanensis sp. nov., Isolated from a Tepid Spring.

It was brought to our attention that the proposed name Paenibacillus yunnanensis is an illegitimate homonym of Paenibacillus yunnanensis Niu et al. 2015. We therefore propose changing the name of the newly proposed species to Paenibacillus tengchongensis as follows.

Description of Paenibacillus yunnanensis sp. nov., Isolated from a Tepid Spring.

A Gram stain-positive, rod-shaped and motile bacterium, designated SYSU G01003T was isolated from a sediment sample collected from tepid spring in Tengchong, Yunnan province, southwestern China. Growth observed at temperature ranging 28-37 °C (optimum 37 °C) and pH 6.0-8.0 (optimum pH 7.0). Tolerance to NaCl was up to 2.5% (w/v) (optimal in the absence of NaCl). The cell wall peptidoglycan is meso-2,6-diaminopimelic acid and MK-7 as the only respiratory quinone. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and unidentified aminophospholipid, phospholipid, and polar lipid. The major fatty acids are C16:0, anteiso-C15:0 and C14:0. The genomic DNA G + C content of the type strain was 54.0 mol%. The average nucleotide identity (ANIb and ANIm) values between SYSU G01003T and Paenibacillus azotifigens LMG 29963T were below the cut-off level (95-96%) recommended as the average nucleotide identity (ANI) criterion for interspecies identity. Based on the above results strain SYSU G01003T represents a novel species of the genus Paenibacillus, for which the name Paenibacillus yunnanensis sp. nov. is proposed. The type strain, SYSU G01003T (=KCTC 43132T = CGMCC 1.17384T).

Description of Halegenticoccus soli gen. nov., sp. nov., a halophilic archaeon isolated from a soil sample of Ebi lake.

Two extreme halophilic archaeal strains, SYSUA9-0T and SYSUA9-1, were isolated from Ebi lake of Xinjiang, China. The colonies were Gram-negative, coccoid, and non-motile. Strains were aerobic and grew at 25-50 °C (optimum at 37 °C), in the presence of 10-35% (w/v) NaCl (optimum at 20-22%), and pH 6.0-8.0 (optimum at 7.0). The 16S rRNA gene sequence result revealed that the two strains were closely related to Haloprofundus marisrubri SB9T (92.7% similarity). The DNA-DNA hybridization value (97% ± 1%) suggested that SYSUA9-0T and SYSUA9-1 were similar; however, their sequence similarities with other archaeal members suggested that they were novel candidates. The genomic G + C content of SYSUA9-0T was 66.9%. The average nucleotide identity value between SYSU A9-0T and Haloprofundus marisrubri SB9T was 69.1%, which was far below the cutoff value (95-96%) proposed to define the species boundary. The polar lipids were phosphatidylglycerol (PG), phosphatidylglycerolphosphate methylester (PGP-Me), sulfated mannosyl glucosyl diether, mannosyl glucosyldiether, and four unidentified glycolipids. Phenotypic, chemotaxonomic and comparative genome analysis suggested that SYSU A9-0T and SYSU A9-1 represent a novel species of a new genus within the family Haloferacaceae, for which the name Halegenticoccus soli gen. nov., sp. nov., is proposed. The type strain is SYAUA9-0T (= KCTC4241T = CGMCC 1.15765T).

Olivibacter flavus sp. nov., a novel endophytic bacterium isolated from the root of Camellia sinensis.

A novel Gram-negative rod, endophytic bacterium, designated strain TMCC 8258T, was isolated from the root of Camellia sinensis collected from Puer, south-west China. Comparative 16S rRNA gene sequence analysis showed that the strain belongs to the family Sphingobacteriaceae and a neighbour-joining phylogenetic tree suggested that strain TMCC 8258T formed a cluster with the type strain of Olivibacter ginsengisoli (showed the highest 16S rRNA gene sequence similarity of 95.8%). Chemotaxonomic data [major fatty acid iso-C15:0, summed feature 3 (C16:1 ω7c and/or C16:1 ω6c), iso-C17:0 3-OH and major respiratory quinone MK-7] confirmed the affiliation of strain TMCC 8258T to the genus Olivibacter. The G + C content was 39.1 mol %. The results of the phylogenetic analysis, together with the physiological, morphological and biochemical tests, suggested that strain TMCC 8258T should be classified as representing a novel species of the genus Olivibacter, for which the name Olivibacter flavus is proposed. The type strain is TMCC 8258T (=CGMCC 1.16141 = KCTC 42683).

Saliphagus infecundisoli gen. nov., sp. nov., an extremely halophilic archaeon isolated from a saline soil.

Two extremely halophilic archaea, strains YIM 93745T and YIM 93707, were isolated from a saline soil sample collected from Loulan, China. Cells of the two strains were coccus, non-motile and Gram-stain negative. The strains were aerobic and grew at 25-50 °C (optimum, 37 °C), in the presence of 5-35 % (w/v) NaCl (optimum, 20 %), 0.01-0.1 M Mg2+ (optimum, 0.03 M) and pH 6.0-8.5 (optimum, 7.0-7.5). Cells lysed in distilled water and with 0-5 % NaCl. Major polar lipids were phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulfate, sulfated mannosyl glycosyl diether and two unidentified glycolipids. Phylogenetic analysis based on the 16S rRNA sequence revealed that the two strains were most closely related to Halovivax cerinus IC35T (95.1 and 95.2 % sequence similarities, respectively). The two strains, however, shared highest rpoB' gene sequence identities with Natrinema pellirubrum JCM 10476T (87.8 and 87.7 % respectively). Phylogenetic trees based on 16S rRNA and rpoB' gene sequences demonstrated a robust clade of the two strains with members of related genera of the family Natrialbaceae. The DNA G+C contents of the two strains were 64.6 and 64.4 mol%, respectively. DNA-DNA relatedness values between them were 95±2 %. Phenotypic, chemotaxonomic characteristics and phylogenetic properties suggested that the two strains YIM 93745T and YIM 93707 represent a novel species in a new genus within the family Natrialbaceae, for which the name Saliphagus infecundisoli gen. nov., sp. nov. is proposed. The type strain is YIM 93745T (=KCTC 4228T=CGMCC 1.15824T).

Siccirubricoccus deserti gen. nov., sp. nov., a proteobacterium isolated from a desert sample.

Strain SYSU D8009T was isolated from a desert sample collected from Saudi Arabia. The taxonomic position of the isolate was investigated by a polyphasic approach. The novel isolate was Gram-stain-negative, non-motile, aerobic and non-spore-forming. It was able to grow at 4-45 °C and pH 4.0-8.0, and exhibited NaCl tolerance of up to 1.5 % (w/v). Strain SYSU D8009T shared the closest 16S rRNA gene sequence similarities with members of the family Acetobacteraceae, with a value of less than 96.0 %. In the phylogenetic dendrograms, the strain clustered with the genera Paracraurococcus, Craurococcus and Crenalkalicoccus within the family Acetobacteraceae but with a distinct lineage, thereby demonstrating that the strain should be classified within the family Acetobacteraceae. The respiratory ubiquinone was found to be Q-10. The polar lipids of the strain comprised diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol and four unidentified aminolipids. The predominant cellular fatty acids were summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c) and C16 : 0. The genomic DNA G+C content of strain SYSU D8009T was determined to be 71.6 mol%. Based on the results of the phylogenetic analyses and differences in the physiological and biochemical characteristics, strain SYSU D8009T merits representation of a novel species of a new genus within the family Acetobacteraceae, for which the name Siccirubricoccus deserti gen. nov., sp. nov. is proposed. The type strain of Siccirubricoccus deserti sp. nov. is SYSU D8009T (=CGMCC 1.15936T=KCTC 62088T).

Redox-dependent Ligand Switching in a Sensory Heme-binding GAF Domain of the Cyanobacterium Nostoc sp. PCC7120.

The genome of the cyanobacterium Nostoc sp. PCC7120 carries three genes (all4978, all7016, and alr7522) encoding putative heme-binding GAF (cGMP-specific phosphodiesterases, adenylyl cyclases, and FhlA) proteins that were annotated as transcriptional regulators. They are composed of an N-terminal cofactor domain and a C-terminal helix-turn-helix motif. All4978 showed the highest affinity for protoheme binding. The heme binding capability of All7016 was moderate, and Alr7522 did not bind heme at all. The "as isolated" form of All4978, identified by Soret band (λmax = 427 nm), was assigned by electronic absorption, EPR, and resonance Raman spectroscopy as a hexa-coordinated low spin Fe(III) heme with a distal cysteine ligand (absorption of δ-band around 360 nm). The protoheme cofactor is noncovalently incorporated. Reduction of the heme could be accomplished by chemically using sodium dithionite and electrospectrochemically; this latter method yielded remarkably low midpoint potentials of -445 and -453 mV (following Soret and α-band absorption changes, respectively). The reduced form of the heme (Fe(II) state) binds both NO and CO. Cysteine coordination of the as isolated Fe(III) protein is unambiguous, but interestingly, the reduced heme instead displays spectral features indicative of histidine coordination. Cys-His ligand switches have been reported as putative signaling mechanisms in other heme-binding proteins; however, these novel cyanobacterial proteins are the first where such a ligand-switch mechanism has been observed in a GAF domain. DNA binding of the helix-turn-helix domain was investigated using a DNA sequence motif from its own promoter region. Formation of a protein-DNA complex preferentially formed in ferric state of the protein.

Aurantimonas endophytica sp. nov., a novel endophytic bacterium isolated from roots of Anabasis elatior (C. A. Mey.) Schischk.

An orange-coloured, aerobic, motile, short-rod-shaped bacterial strain, designated EGI 6500337T, was isolated from the surface-sterilized root of a halophyte, Anabasis elatior (C. A. Mey.) Schischk, collected from Urumqi, Xinjiang province, north-west China. Growth occurred at 5-35 °C (optimum 30 °C), at pH 6.0-9.0 (optimum pH 7.0) and in the presence of 0-6 % (w/v) NaCl (optimum 0-1 %). Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain EGI 6500337T formed a distinct lineage in the cluster that comprised the genera Aurantimonas and Aureimonas in the family Aurantimonadaceae. The 16S rRNA gene sequence of strain EGI 6500337T shared highest similarity with those of Aurantimonas coralicida DSM 14790T (97.15 %) and Aurantimonas manganoxydans DSM 21871T (97.15 %). Strain EGI 6500337T contained Q-10 as the dominant isoprenoid quinone. The major cellular fatty acids were C18 : 1ω7c and C19 : 0ω8c cyclo. The polar lipid profile of strain EGI 6500337T contained diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine and phosphatidylethanolamine as major components, similarly to members of the genus Aurantimonas. The DNA G+C content of strain EGI 6500337T was 66.8 mol%. The level of DNA-DNA relatedness between strain EGI 6500337T and Aurantimonas coralicida DSM 14790T was 24.7±2.9 %. On the basis of the phylogenetic analysis, chemotaxonomic data and phenotypic characteristics, strain EGI 6500337T represents a novel species of the genus Aurantimonas, for which the name Aurantimonas endophytica sp. nov. is proposed. The type strain is EGI 6500337T (=KCTC 52296T=CPCC 100904T).

Mariniluteicoccus endophyticus sp. nov., an endophytic actinobacterium isolated from root of Ocimum basilicum.

Two strains of Gram-stain-positive, aerobic, non-motile, irregular coccus-shaped bacteria, designated YIM 2617T and YIM 2617-2, were isolated from the root of Ocimum basilicum. Phylogenetic analysis on the basis of 16S rRNA gene sequence comparison revealed that the two strains were closely related to Mariniluteicoccus flavus YIM M13146T (98.1 and 98.0 % similarities, respectively) and formed a robust clade with M. flavus in the neighbour-joining tree. Optimum growth of the strains was observed at 28-32 °C, at pH 7.0-8.0 and in the presence of 0-2 % (w/v) NaCl. The chemotaxonomic profiles of the strains comprised anteiso-C15 : 0 as the major cellular fatty acid, MK-9(H4) as the predominant menaquinone, alanine, glycine, glutamic acid and ll-diaminopimelic acid as peptidoglycan components, and phosphatidylcholine and diphosphatidylglycerol as the major polar lipids. The G+C contents of the genomic DNA of strains YIM 2617T and YIM 2617-2 were 66.4 and 66.6 mol%, respectively. DNA-DNA hybridizations of the two strains with M. flavus YIM M13146T gave mean relatedness values of 47.6 ± 2.0 and 43.2 ± 1.5 %, respectively, while the relatedness value between them was 92.1 ± 2.2 %. On the basis of the data recorded from the present study, strains YIM 2617T and YIM 2617-2 represent a novel species of the genus Mariniluteicoccus, for which the name Mariniluteicoccus endophyticus sp. nov. is proposed. The type strain is YIM 2617T ( = KCTC 29482T = DSM 28728T = JCM 30097T).