A modular toolkit for environmental Rhodococcus, Gordonia, and Nocardia enables complex metabolic manipulation.

Soil-dwelling Actinomycetes are a diverse and ubiquitous component of the global microbiome but largely lack genetic tools comparable to those available in model species such as Escherichia coli or Pseudomonas putida, posing a fundamental barrier to their characterization and utilization as hosts for biotechnology. To address this, we have developed a modular plasmid assembly framework, along with a series of genetic control elements for the previously genetically intractable Gram-positive environmental isolate Rhodococcus ruber C208, and demonstrate conserved functionality in 11 additional environmental isolates of Rhodococcus, Nocardia, and Gordonia. This toolkit encompasses five Mycobacteriale origins of replication, five broad-host-range antibiotic resistance markers, transcriptional and translational control elements, fluorescent reporters, a tetracycline-inducible system, and a counter-selectable marker. We use this toolkit to interrogate the carotenoid biosynthesis pathway in Rhodococcus erythropolis N9T-4, a weakly carotenogenic environmental isolate and engineer higher pathway flux toward the keto-carotenoid canthaxanthin. This work establishes several new genetic tools for environmental Mycobacteriales and provides a synthetic biology framework to support the design of complex genetic circuits in these species.IMPORTANCESoil-dwelling Actinomycetes, particularly the Mycobacteriales, include both diverse new hosts for sustainable biomanufacturing and emerging opportunistic pathogens. Rhodococcus, Gordonia, and Nocardia are three abundant genera with particularly flexible metabolisms and untapped potential for natural product discovery. Among these, Rhodococcus ruber C208 was shown to degrade polyethylene; Gordonia paraffinivorans can assimilate carbon from solid hydrocarbons; and Nocardia neocaledoniensis (and many other Nocardia spp.) possesses dual isoprenoid biosynthesis pathways. Many species accumulate high levels of carotenoid pigments, indicative of highly active isoprenoid biosynthesis pathways which may be harnessed for fermentation of terpenes and other commodity isoprenoids. Modular genetic toolkits have proven valuable for both fundamental and applied research in model organisms, but such tools are lacking for most Actinomycetes. Our suite of genetic tools and DNA assembly framework were developed for broad functionality and to facilitate rapid prototyping of genetic constructs in these organisms.

Gordonia prachuapensis sp. nov. and Gordonia sesuvii sp. nov., two novel actinobacteria isolated from mangrove sediments and leaves of halophyte Sesuvium portulacastrum in Thailand.

A polyphasic approach was used to characterize two novel actinobacterial strains, designated PKS22-38T and LSe1-13T, which were isolated from mangrove soils and leaves of halophyte Sesuvium portulacastrum (L.), respectively. Phylogenetic analyses based on 16S rRNA gene sequences showed that they belonged to the genus Gordonia and were most closely related to three validly published species with similarities ranging from 98.6 to 98.1 %. The genomic DNA G+C contents of strains PKS22-38T and LSe1-13T were 67.3 and 67.2 mol%, respectively. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between the two strains were 93.3 and 54.9 %, respectively, revealing that they are independent species. Meanwhile, the ANI and dDDH values between the two novel strains and closely related type strains were below 80.5 and 24.0 %, respectively. Strains PKS22-38T and LSe1-13T contained C16 : 0, C18 : 1 ω9c and C18 : 0 10-methyl (TBSA) as the major fatty acids and diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylinositol as the main phospholipids. The predominant menaquinone was MK-9(H2). Based on phenotypic, chemotaxonomic, phylogenetic and genomic data, strains PKS22-38T and LSe1-13T are considered to represent two novel species within the genus Gordonia, for which the names Gordonia prachuapensis sp. nov. and Gordonia sesuvii sp. nov. are proposed, with strain PKS22-38T (=TBRC 17540T=NBRC 116256T) and strain LSe1-13T (=TBRC 17706T=NBRC 116396T) as the type strains, respectively.

Biodegradation of low-density polyethylene film by two bacteria isolated from plastic debris in coastal beach.

Low-density polyethylene (LDPE) conduces massive environmental accumulation due to its high production and recalcitrance to environment. In this study, We successfully enriched and isolated two strains, Nitratireductor sp. Z-1 and Gordonia sp. Z-2, from coastal plastic debris capable of degrading LDPE film. After a 30-day incubation at 30 ℃, strains Z-1 and Z-2 decreased the weight of branched-LDPE (BLDPE) film by 2.59 % and 10.27 % respectively. Furthermore, high temperature gel permeation chromatography (HT-GPC) analysis revealed molecular weight reductions of 7.69 % (Z-1) and 23.22 % (Z-2) in the BLDPE film. Scanning electron microscope (SEM) image showed the presence of microbial colonization and perforations on the film's surface. Fourier transform infrared spectroscopy (FTIR) analysis indicated novel functional groups, such as carbonyl and carbon-carbon double bonds in LDPE films. During LDPE degradation, both strains produced extracellular reactive oxygen species (ROS). GC-MS analysis revealed the degradation products included short-chain alkanes, alkanols, fatty acids, and esters. Genomic analysis identified numerous extracellular enzymes potentially involved in LDPE chain scission. A model was proposed suggesting a coordinated role between ROS and extracellular enzymes in the biodegradation of LDPE. This indicates strains Z-1 and Z-2 can degrade LDPE, providing a basis for deeper exploration of biodegradation mechanisms.

Efficient biodegradation of Polyethylene terephthalate (PET) plastic by Gordonia sp. CN2K isolated from plastic contaminated environment.

Since we rely entirely on plastics or their products in our daily lives, plastics are the invention of the hour. Polyester plastics, such as Polyethylene Terephthalate (PET), are among the most often used types of plastics. PET plastics have a high ratio of aromatic components, which makes them very resistant to microbial attack and highly persistent. As a result, massive amounts of plastic trash accumulate in the environment, where they eventually transform into microplastic (<5 mm). Rather than macroplastics, microplastics are starting to pose a serious hazard to the environment. It is imperative that these polymer microplastics be broken down. Through the use of enrichment culture, the PET microplastic-degrading bacterium was isolated from solid waste management yards. Bacterial strain was identified as Gordonia sp. CN2K by 16 S rDNA sequence analysis and biochemical characterization. It is able to use polyethylene terephthalate as its only energy and carbon source. In 45 days, 40.43 % of the PET microplastic was degraded. By using mass spectral analysis and HPLC to characterize the metabolites produced during PET breakdown, the degradation of PET is verified. The metabolites identified in the spent medium included dimer compound, bis (2-hydroxyethyl) terephthalate (BHET), mono (2-hydroxyethyl) terephthalate (MHET), and terephthalate. Furthermore, the PET sheet exposed to the culture showed considerable surface alterations in the scanning electron microscope images. This illustrates how new the current work is.

Characteristics and Treatment of Gordonia spp. Bacteremia, France.

Systemic Gordonia spp. infections are rare and occur mostly among immunocompromised patients. We analyzed 10 cases of Gordonia bacteremia diagnosed in 3 tertiary care centers in France to assess risk factors, treatment, and clinical outcomes. Most patients were cured within 10 days by using ß-lactam antimicrobial therapy and removing central catheters.

Evaluation of distinct molecular architectures and coordinated regulation of the catabolic pathways of oestrogenic dioctyl phthalate isomers in Gordonia sp.

Bacterial strain GONU, belonging to the genus Gordonia, was isolated from a municipal waste-contaminated soil sample and was capable of utilizing an array of endocrine-disrupting phthalate diesters, including di-n-octyl phthalate (DnOP) and its isomer di(2-ethylhexyl) phthalate (DEHP), as the sole carbon and energy sources. The biochemical pathways of the degradation of DnOP and DEHP were evaluated in strain GONU by using a combination of various chromatographic, spectrometric and enzymatic analyses. Further, the upregulation of three different esterases (estG2, estG3 and estG5), a phthalic acid (PA)-metabolizing pht operon and a protocatechuic acid (PCA)-metabolizing pca operon were revealed based on de novo whole genome sequence information and substrate-induced protein profiling by LC-ESI-MS/MS analysis followed by differential gene expression by real-time PCR. Subsequently, functional characterization of the differentially upregulated esterases on the inducible hydrolytic metabolism of DnOP and DEHP revealed that EstG5 is involved in the hydrolysis of DnOP to PA, whereas EstG2 and EstG3 are involved in the metabolism of DEHP to PA. Finally, gene knockout experiments further validated the role of EstG2 and EstG5, and the present study deciphered the inducible regulation of the specific genes and operons in the assimilation of DOP isomers.

Gordonia metallireducens sp. nov., a tellurite- and selenite-resistant bacterium isolated from the sediment of an acid mine drainage stream.

A polyphasic taxonomic study was carried out on strain TSed Te1T, isolated from sediment of a stream contaminated with acid drainage from a coal mine. The bacterium forms pink-pigmented colonies and has a rod-coccus growth cycle, which also includes some coryneform arrangements. This bacterium is capable of growing in the presence of up to 750 µg ml-1 tellurite and 5000 µg ml-1 selenite, reducing each to elemental form. Nearly complete 16S rRNA gene sequence analysis associated the strain with Gordonia, with 99.5 and 99.3 % similarity to Gordonia namibiensis and Gordonia rubripertincta, respectively. Computation of the average nucleotide identity and digital DNA-DNA hybridization comparisons with the closest phylogenetic neighbour of TSed Te1T revealed genetic differences at the species level, which were further substantiated by differences in several physiological characteristics. The dominant fatty acids were C16 : 0, C18 : 1, C16 : 1 and tuberculostearic acid. The DNA G+C content was 67.6 mol%. Major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and phosphatidylinositol mannoside, while MK-9(H2) was the only menaquinone found. Mycolic acids of C56-C60 were present. Whole-cell hydrolysates contained meso-diaminopimelic acid along with arabinose and galactose as the major cell-wall sugars. On the basis of the results obtained in this study, the bacterium was assigned to the genus Gordonia and represents a new species with the name Gordonia metallireducens sp. nov. The type strain is TSed Te1T (=NRRL B-65678T=DSM 114093T).

Gordonia aquimaris sp. nov., a novel marine actinobacterium isolated from seawater in the upper gulf of Thailand.

An actinobacterium strain, SW21T, was isolated from seawater collected in the upper Gulf of Thailand. Cells were Gram-stain-positive, aerobic and rod-shaped. Growth was observed from 15 to 37 °C and at pH 6-8. Maximum NaCl for growth was 14 % (w/v). meso-Diaminopimelic acid, arabinose, galactose, glucose, rhamnose and ribose were detected in the whole-cell hydrolysate. Diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and phosphatidylinositol mannoside were detected as the phospholipids in the cells. The major menaquinones were MK-9(H2) and MK-7(H2). The major cellular fatty acids were C16 : 0, C18 : 1 ω9c, C18 : 0 and C18 : 010-methyl (TBSA). The 16S rRNA gene sequence data supported the assignment of strain SW21T to the genus Gordonia and showed that Gordonia mangrovi KCTC 49383T (98.7 %) was the closest relative. Moreover, the average nucleotide identity-blast (85.5 %) and digital DNA-DNA hybridization (30.7 %) values between strain SW21T and its closest neighbour were below the threshold values for delineation of a novel species. The combination of genotypic and phenotypic data indicated that strain SW21T is representative of novel species of the genus Gordonia. The name Gordonia aquimaris sp. nov. is proposed for strain SW21T. The type strain is SW21T (=TBRC 15691T=NBRC 115558T).

Synthetic bacterial consortia enhanced the degradation of mixed priority phthalate ester pollutants.

Dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DBP), butyl benzyl phthalate (BBP), bis(2-ethylhexyl) phthalate (DEHP), and di-n-octyl phthalate (DOP) are hazardous chemicals listed as priority pollutants that disrupt endocrine systems. According to available reports, these six priority phthalate esters (PAEs) are considered the most polluting; however, no studies have been conducted on the efficient remediation of these PAEs. We therefore designed and constructed a synthetic bacterial consortium capable of the simultaneous and efficient degradation of six priority PAEs in minimal inorganic salt medium (MSM) and soil. The consortium comprised Glutamicibacter sp. ZJUTW, which demonstrates priority for degrading short-chain PAEs; Cupriavidus sp. LH1, which degrades phthalic acid (PA) and protocatechuic acid (PCA), intermediates of the PAE biodegradation process; and Gordonia sp. GZ-YC7, which efficiently degrades long-chain priority PAEs, including DEHP and DOP. In MSM containing the six mixed PAEs (250 mg/L each), the ZJUTW + YC + LH1 consortium completely degraded the four short-chain PAEs within 48 h, and DEHP (100%) and DOP (62.5%) within 72 h. In soil containing the six mixed PAEs (DMP, DEP, BBP, and DOP, 400 mg/kg each; DBP and DEHP, 500 mg/kg, each), the ZJUTW + YC + LH1 consortium completely degraded DMP, DEP, BBP, and DBP within 6 days, and 70.84% of DEHP and 66.24% of DOP within 2 weeks. The consortium efficiently degraded the six mixed PAEs in both MSM and soil. We thus believe that this synthetic microbial consortium is a strong candidate for the bioremediation of environments contaminated with mixed PAE pollutants.

Biotransformation of 3-cyanopyridine to nicotinic acid using whole-cell nitrilase of Gordonia terrae mutant MN12.

In the present study, the Gordonia terrae was subjected to chemical mutagenesis using ethyl methane sulfonate (EMS) and methyl methane sulfonate (MMS), N-methyl-N-nitro-N-nitrosoguanidine (MNNG), 5-bromouracil (5-BU) and hydroxylamine with the aim of improving the catalytic efficiency of its nitrilase for conversion of 3-cyanopyridine to nicotinic acid. A mutant MN12 generated with MNNG exhibited increase in nitrilase activity from 0.5 U/mg dcw (dry cell weight) (in the wild G. terrae) to 1.33 U/mg dcw. Further optimizations of culture conditions using response surface methodology enhanced the enzyme production to 1.2-fold. Whole-cell catalysis was adopted for bench-scale synthesis of nicotinic acid, and 100% conversion of 100 mM 3-cyanopyridine was achieved in potassium phosphate buffer (0.1 M, pH 8.0) at 40 °C in 15 min. The whole-cell nitrilase of the mutant MN12 exhibited higher rate of product formation and volumetric productivity, i.e., 24.56 g/h/g dcw and 221 g/L as compared to 8.95 g/h/g dcw and 196.8 g/L of the wild G. terrae. The recovered product was confirmed by HPLC, FTIR and NMR analysis with high purity (> 99.9%). These results indicated that the mutant MN12 of G. terrae as whole-cell nitrilase is a very promising biocatalyst for the large-scale synthesis of nicotinic acid.

Diagnosis and Treatment of Gordonia Species Infection in a Peach-Faced Lovebird (Agapornis roseicollis).

Respiratory distress is a common presentation for avian species. A 9-week-old peach-faced lovebird (Agapornis roseicollis) was presented with a 2-week history of progressive dyspnea. Computed tomographic (CT) images were suggestive of splenomegaly and bilateral granulomatous pulmonary disease. Polymerase chain reaction testing of samples from the choana, cloaca, and distal tracheal/syringeal area were positive for Mycobacterium species hsp65. A comparison search of the 400 base pair sequence in the NCBI/BLAST/blastn database revealed a best match of 93% similarity to Gordonia species and 91% similarity to Gordonia bronchialis. Gordonia is a genus in the phylum Actinomycetota, the same lineage that includes Mycobacterium species. Gordonia species can be mistaken for Mycobacterium species unless more definitive diagnostic testing is pursued. Infection caused by Gordonia species is rare in humans. Reports commonly cite infection of immunocompromised patients, and to our knowledge, no reports of treatment have been published in the veterinary literature. After the test results were obtained, the patient was treated with azithromycin and pradofloxacin for 3 months. The lovebird was presented for reexamination when the antibiotic treatment was complete. When reexamined, and a second series of CT images evaluated, it was determined that the treatment achieved clinical resolution of signs and lesions.

Gordonia zhenghanii sp. nov. and Gordonia liuliyuniae sp. nov., isolated from bat faeces.

Four mesophilic actinobacteria (HY002T, HY442, HY366T and HY285) isolated from the faeces of bats collected in southern China were found to be strictly aerobic, non-motile, rod-shaped, oxidase-negative, Gram-stain-positive and catalase-positive. Strains HY002T and HY366T contained meso-diaminopimelic acid as the diagnostic diamino acid and MK-9(H2) the sole respiratory quinone. Arabinose, galactose and ribose were detected in the whole-cell hydrolysates of both type strains. The main cellular fatty acids (> 10.0%) of all strains were C16 : 0, C18 : 1 ω9c, 10-methyl-C18 : 0 and summed feature 3. Strains HY002T and HY366T contained diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and phosphatidyl inositol mannosides as the major polar lipids. The phylogenetic/phylogenomic analyses based on 16S rRNA gene and genomic sequence comparison revealed that the four strains belong to the genus Gordonia, most closely related to G. neofelifaecis NRRL B-59395T(98.2-98.3% sequence similarity) on the EzBioCloud database. The G+C contents of strains HY002T and HY366T based on genomic DNA were 66.5 and 66.9%, respectively. The DNA-DNA relatedness values between the two types strains and members of the genus Gordonia were far below 70 % (18.6-23.1 %). All genotypic and phenotypic data indicated that the four strains are representatives of two novel separate species, for which the names Gordonia zhenghanii sp. nov. and Gordonia liuliyuniae sp. nov. are proposed, with HY002T (=CGMCC 4 7757T=JCM 34 878T) and HY366T (=CGMCC 1 19146T=JCM 34 879T) as the respective type strains.

Gordonia tangerina sp. nov., isolated from seawater.

A Gram-stain-positive, aerobic bacterium, designated GW1C4-4T, was isolated from the seawater sample from the tidal zone of Guanyinshan Coast, Xiamen, Fujian Province, PR China. The strain was reddish-orange, rod-shaped and non-motile. Cells of strain GW1C4-4T were oxidase-negative and catalase-positive. The strain could grow at 10-42 °C (optimum, 32-35 °C), pH 5-9 (optimum, pH 6) and with 0-10 % NaCl (w/v; optimum, 1 %). Phylogenetic analysis based on the 16S rRNA sequences indicated that strain GW1C4-4T belonged to the genus Gordonia, having the highest similarity to Gordonia mangrovi HNM0687T (98.5 %), followed by Gordonia bronchialis DSM 43247T (98.4 %). The G+C DNA content was 66.5 mol %. Average nucleotide identity and digital DNA-DNA hybridization values between strain GW1C4-4T and G. mangrovi HNM0687T were 85.8 and 30.0 %, respectively. The principal fatty acids of strain GW1C4-4T were C16 : 0, C18 : 0 10-methyl (TBSA) and summed feature 3 (C16 : 1 ω7c/C16 : 1 ω6c). MK-9 (H2) was the sole respiratory quinone. The polar lipids included diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine and an unidentified lipid. Based on its phylogenetic, phenotypic, chemotaxonomic and genomic characteristics, it is proposed that strain GW1C4-4T represents a novel species within the genus Gordonia, for which the name Gordonia tangerina sp. nov. is proposed. The type strain is GW1C4-4T (=MCCC 1A18727T=KCTC 49729T).

Gordonia pseudamarae sp. nov., a home for novel actinobacteria isolated from stable foams on activated sludge wastewater treatment plants.

The taxonomic status of two Gordonia strains, designated BEN371 and CON9T, isolated from stable foams on activated sludge plants was the subject of a polyphasic study which also included the type strains of Gordonia species and three authenticated Gordonia amarae strains recovered from such foams. Phylogenetic analyses of 16S rRNA gene sequences showed that these isolates formed a compact cluster suggesting a well-supported lineage together with a second branch containing the G. amarae strains. A phylogenomic tree based on sequences of 92 core genes extracted from whole genome sequences of the isolates, the G. amarae strains and Gordonia type strains confirmed the assignment of the isolates and the G. amarae strains to separate but closely associated lineages. Average nucleotide index (ANI) and digital DNA-DNA hybridisation (dDDH) similarities showed that BEN371 and CON9T belonged to the same species and had chemotaxonomic and morphological features consistent with their assignment to the genus Gordonia. The isolates and the G. amarae strains were distinguished using a range of phenotypic features and by low ANI and dDDH values of 84.2 and 27.0 %, respectively. These data supplemented with associated genome characteristics show that BEN371 and CON9T represent a novel species of the genus Gordonia. The name proposed for members of this taxon is Gordonia pseudamarae sp. nov. with isolate CON9T (=DSM 43602T=JCM 35249T) as the type strain.

Peritoneal dialysis-related peritonitis caused by Gordonia bronchialis: first pediatric report.

INTRODUCTION: Gordonia species, aerobic, weakly acid-fast, Gram-positive bacilli, are a rare cause of peritonitis in patients undergoing peritoneal dialysis (PD). We report the first pediatric case of PD-related peritonitis caused by Gordonia bronchialis. CASE PRESENTATION: A 13-year-old girl with chronic kidney disease (CKD) stage 5D, on continuous cycling PD (CCPD) for 8 years, presented with cloudy PD effluent, with no abdominal discomfort or fever. Intra-peritoneal (IP) loading doses of vancomycin and ceftazidime were started at home after obtaining a PD effluent sample, which showed WBC 2,340 × 10 /L (59% neutrophils) and Gram-positive bacilli. On admission, she was clinically well and afebrile, with no history of methicillin-resistant Staphylococcus aureus (MRSA) infection, so vancomycin was discontinued, and IP ceftazidime and cefazolin were started, following a loading dose of intravenous cefazolin. Gordonia species grew after 5 days of incubation and later identified as Gordonia bronchialis. IP vancomycin was restarted as monotherapy, empirically for a total of 3 weeks therapy. A 2-week course of oral ciprofloxacin was added, based on susceptibility testing. PD catheter replacement was advised due to the risk of recurrence but was refused. A relapse occurred 16 days after discontinuing antibiotics, successfully treated with a 2-week course of IP ceftazidime and vancomycin. The PD catheter was removed and hemodialysis initiated. She received a further 2-week course of oral ciprofloxacin and amoxicillin-clavulanate post PD catheter removal. CONCLUSIONS: Gordonia bronchialis is an emerging pathogen in PD peritonitis and appears to be associated with a high risk of relapse. PD catheter replacement is strongly suggested.

A pediatric case of Gordonia otitidis bacteremia detected by long-term blood culture.

For immunocompromised patients receiving chemotherapy or bone mallow transplantation, slow-growing bacteria should also be considered one of the pathogenic microorganisms. However, there is no evidence pertaining to the microbiological tests associated with a patient with febrile neutropenia before peripheral blood stem cell harvest (PBSCH). We report a case of a 4-year-old cancer-bearing female presenting with a catheter-related bloodstream infection due to Gordonia otitidis. We detected G. otitidis from long-term blood cultures for approximately 6 days and prevented iatrogenic bacteremia by identifying the same organism from the culture of the PBSC sample and postponing the scheduled PBSCH. If febrile neutropenia occurs before PBSCH, we should collect multiple sets of blood cultures and culture them for a longer period.

Biological control of problematic bacterial populations causing foaming in activated sludge wastewater treatment plants-phage therapy and beyond.

The production of a stable foam on the surfaces of reactors is a global operating problem in activated sludge plants. In many cases, these foams are stabilized by hydrophobic members of the Mycolata, a group of Actinobacteria whose outer membranes contain long-chain hydroxylated mycolic acids. There is currently no single strategy which works for all foams. One attractive approach is to use lytic bacteriophages specific for the foam stabilizing Mycolata population. Such phages are present in activated sludge mixed liquor and can be recovered readily from it. However, no phage has been recovered which lyses Gordonia amarae and Gordonia pseudoamarae, probably the most common foaming Mycolata members. Whole genome sequencing revealed that both G. amarae and G. pseudoamarae from plants around the world are particularly well endowed with genes encoding antiviral defence mechanisms. However, both these populations were lysed rapidly by a parasitic nanobacterium isolated from a plant in Australia. This organism, a member of the Saccharibacteria, was also effective against many other Mycolata, thus providing a potential agent for control of foams stabilized by them.

Biodegradation and metabolic pathway of phenanthrene by a newly isolated bacterium Gordonia sp. SCSIO19801.

The bacterium Gordonia sp. SCSIO19801, which could effectively utilize phenanthrene as the sole carbon source, was isolated from the seawater of the South China Sea. Its biodegradation characteristics, whole genome sequence, and biodegradation pathway were investigated. The phenanthrene biodegradation process of Gordonia sp. SCSIO19801 was estimated to be a first-order kinetic model with a k value of 0.26/day. Based on the identification of metabolites, utilization of probable intermediates, and genomics analysis of related genes, the degradation of phenanthrene by Gordonia sp. SCSIO19801 was proposed to occur via the salicylate metabolic pathway. This is the first report of a phenanthrene degradation pathway in Gordonia species. In addition, the Gordonia sp. SCSIO19801 could use other aromatic compounds as the sole source of carbon and energy. These characteristics indicate that Gordonia sp. SCSIO19801 can be utilized for developing effective methods for the biodegradation of petroleum hydrocarbons in marine environments.

Gordonia jinghuaiqii sp. nov. and Gordonia zhaorongruii sp. nov., isolated from Tibetan Plateau wildlife.

Four mesophilic and Gram-stain-positive strains (zg-686T/zg-691 and HY186T/HY189) isolated from Tibetan Plateau wildlife (PR China) belong to the genus Gordonia according to 16S rRNA gene and genomic sequence-based phylogenetic/genomic results. They have a DNA G+C content range of 67.4-68.3 mol% and low DNA relatedness (19.2-27.6 %) with all available genomes in the genus Gordonia. Strains zg-686T/zg-691 and HY186T/HY189 had C18 : 1ω9c, C18 : 0 10-methyl, C16 : 1 ω7c/C16 : 1ω6c and C16 : 0 as major cellular fatty acids. The polar lipids detected in strains zg-686T and HY186T included diphosphatidylglycerol, phosphatidylethanolamine, phosphatidyl inositol mannoside and phosphatidylinositol. The respiratory quinones comprised MK8(H2) (10.8 %) and MK9(H2) (89.2 %) for strain zg-686T, and MK6 (7.7 %), MK8(H2) (8.4 %), MK8(H4) (3.1 %) and MK9(H2) (80.8 %) for strain HY186T. Optimal growth conditions were pH 7.0, 35-37 °C and 0.5-1.5 % NaCl (w/v) for strains pair zg-686T/zg-691, and pH 7.0, 28 °C and 1.5 % (w/v) NaCl for strains pair HY186T/HY189. Based on these genotypic and phenotypic results, these four strains could be classified as two different novel species in the genus Gordonia, for which the names Gordonia jinghuaiqii sp. nov. and Gordonia zhaorongruii sp. nov. are proposed. The type strains are zg-686T (=GDMCC 1.1715T =JCM 33890T) and HY186T (=CGMCC 4.7607T =JCM 33466T), respectively.

Cliona varians-Derived Actinomycetes as Bioresources of Photoprotection-Related Bioactive End-Products.

Sunscreen and sunblock are crucial skincare products to prevent photoaging and photocarcinogenesis through the addition of chemical filters to absorb or block ultraviolet (UV) radiation. However, several sunscreen and sunblock ingredients, mostly UV filters, have been associated with human and environmental safety concerns. Therefore, the exploration and discovery of promising novel sources of efficient and safer compounds with photoprotection-related activities are currently required. Marine invertebrates, particularly their associated microbiota, are promising providers of specialized metabolites with valuable biotechnological applications. Nevertheless, despite Actinobacteria members being a well-known source of bioactive metabolites, their photoprotective potential has been poorly explored so far. Hence, a set of methanolic extracts obtained from Cliona varians-derived actinomycetes was screened regarding their antioxidant and UV-absorbing capacities (i.e., photoprotection-related activities). The active extract-producing strains were identified and classified within genera Streptomyces, Micrococcus, Gordonia, and Promicromonospora. This is the first report of the isolation of these microorganisms from C. varians (an ecologically important Caribbean coral reef-boring sponge). The in vitro cytotoxicity on dermal fibroblasts of oxybenzone and the selected active extracts revealed that oxybenzone exerted a cytotoxic effect, whereas no cytotoxic effect of test extracts was observed. Accordingly, the most active (SPFi > 5, radical scavenging > 50%) and nontoxic (cell viability > 75%) extracts were obtained from Streptomyces strains. Finally, LC-MS-based characterization suggested a broad chemical space within the test strains and agreed with the reported streptomycetes' chemodiversity. The respective metabolite profiling exposed a strain-specific metabolite occurrence, leading to the recognition of potential hits. These findings suggest that marine Streptomyces produce photoprotectants ought to be further explored in skincare applications.