Sulforaphane triggers iron overload-mediated ferroptosis in gastric carcinoma cells by activating the PI3K/IRP2/DMT1 pathway.

OBJECTIVE: Increasing evidence indicates that prolonged exposure to sulforaphane (SFN) can improve malignancies. However, the role of iron in SFN-triggered death in gastric carcinoma cells and the underlying molecular mechanisms remain unclear. Thus, the current study explored the effects of SFN on iron overload-mediated ferroptosis and the PI3K/IRP2/DMT1 pathway in gastric carcinoma cells. METHODS: We utilized the MGC-803 cell line to assess whether SFN affected iron metabolism and whether this effect contributed to cell death. Pharmacological inhibition of iron metabolism also was performed to determine the molecular mechanism underlying SFN-triggered iron overload and the disturbance in iron metabolism. RESULTS: Our data revealed that SFN treatment altered iron homeostasis and led to iron overload in vitro. Interestingly, SFN-stimulated cell death resulted from ferroptosis, a recently identified iron-dependent form of regulated cell death. Furthermore, an iron chelator, deferiprone, ameliorated the SFN-triggered mitochondrial dysfunction and reduced the iron overload. In addition, we found that the SFN-triggered iron overload was regulated by the PI3K/IRP2/DMT1 signaling pathway. CONCLUSION: We discovered that disturbance in iron metabolism might be involved in the SFN-triggered cell death in gastric carcinoma cells. Blockade of the PI3K/IRP2/DMT1 axis could provide a feedback effect on SFN-induced ferroptosis to protect tumor cells from growth.

Association between serum baseline C1q and IgG levels and the efficacy of combined immunotherapy in patients with esophageal squamous cell carcinoma: a retrospective study.

BACKGROUND: To assess the clinical value of serum complement component 1q (C1q) and immunoglobulin G (IgG) levels in predicting the response to combined immunotherapy in patients with esophageal squamous cell carcinoma. METHODS: We conducted a retrospective study of 44 patients with esophageal squamous cell carcinoma who received combined immunotherapy in our hospital. Serum IgG and C1q levels were collected before and three weeks after immunotherapy treatment, together with other data on clinical and demographic characteristics. RESULTS: Twenty seven patients (61.4%) showed partial response (PR), 13 (29.5%) stable disease (SD), and 4 (9.1%) progressive disease (PD). None of the patients presented complete response (CR). The PR group displayed lower IgG and higher C1q levels both before and after immunotherapy than patients showing SD or PD. The IgG reduction (59.3%) and C1q increment (70.3%) in the PR group three weeks post-treatment were significantly larger than those in patients showing SD or PD. Moreover, the pretreatment C1q level and the post-treatment change of C1q levels were strongly associated with the immunotherapy response. CONCLUSIONS: High pre- and post-treatment C1q levels and reduced post-treatment IgG levels correlate with efficacy of combined immunotherapy in patients with esophageal squamous cell carcinoma. Serum baseline C1q level may predict immunotherapy response in such patients.

Characterization of a novel class A carbapenemase PAD-1 from Paramesorhizobium desertii A-3-ET, a strain highly resistant to ß-lactam antibiotics.

Although clinical antibiotic-resistant bacteria have attracted tremendous attention in the microbiology community, the resistant bacteria that persist in natural environments have been overlooked for a longtime. We previously proposed a new species Paramesorhizobium desertii, isolated from the soil of the Taklimakan Desert in China that is highly resistant to most ß-lactam antibiotics. To identify potential ß-lactamase(s) in this bacteria, we first confirmed the carbapenemase activity in the freeze-thawed supernatant of a P. desertii A-3-ET culture using the modified Hodge assay. We then identified a novel chromosome-encoded carbapenemase (PAD-1) in strain A-3-ET, using a shotgun proteomic analysis of the supernatant and genomic information. The bioinformatics analysis indicated that PAD-1 is a class A carbapenemase. Subsequent enzyme kinetic assays with purified PAD-1 confirmed its carbapenemase activity, which is similar to that of clinically significant class A carbapenemases, including BKC-1 and KPC-2. Because the location in which A-3-ET was isolated is not affected by human activity, PAD-1 is unlikely to be associated with the selection pressures exerted by modern antibiotics. This study confirmed the diversity of antibiotic-resistant determinants in the environmental resistome.

Production of taxadiene by engineering of mevalonate pathway in Escherichia coli and endophytic fungus Alternaria alternata TPF6.

Taxol (paclitaxel) is a diterpenoid compound with significant and extensive applications in the treatment of cancer. The production of Taxol and relevant intermediates by engineered microbes is an attractive alternative to the semichemical synthesis of Taxol. In this study, based on a previously developed platform, the authors first established taxadiene production in mutant E. coli T2 and T4 by engineering of the mevalonate (MVA) pathway. The authors then developed an Agrobacterium tumefaciens-mediated transformation (ATMT) method and verified the strength of heterologous promoters in Alternaria alternata TPF6. The authors next transformed the taxadiene-producing platform into A. alternata TPF6, and the MVA pathway was engineered, with introduction of the plant taxadiene-forming gene. Notably, by co-overexpression of isopentenyl diphosphate isomerase (Idi), a truncated version of 3-hydroxy-3-methylglutaryl-CoA reductase (tHMG1), and taxadiene synthase (TS), the authors could detect 61.9 ± 6.3 µg/L taxadiene in the engineered strain GB127. This is the first demonstration of taxadiene production in filamentous fungi, and the approach presented in this study provides a new method for microbial production of Taxol. The well-established ATMT method and the known promoter strengths facilitated further engineering of taxaenes in this fungus.

Roseomonas arcticisoli sp. nov., isolated from Arctic tundra soil.

A pale pink, Gram-reaction-negative, non-motile, aerobic bacterium, designated MC 3624T, was isolated from a tundra soil near Ny-Ålesund, Svalbard Archipelago, Norway (78° N). Growth occurred at 10-37 °C (optimum 25-30 °C) and at pH 6.0-9.0 (optimum pH 8.0). The predominant fatty acids were C16 : 0 (17.7 %), C18 : 1ω7c 11-methyl (13.4 %), summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) (10.1 %) and summed feature 8 (C18 : 1ω6c and/or C18 : 1ω7c) (38.3 %). The major respiratory quinone was ubiquinone-10, and the main polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylcholine and an unidentified aminolipids. The DNA G+C content was 68.9 mol%. Carotenoids of the spirilloxanthin series were produced. The nearest neighbour to the novel strain was Roseomonas wooponensis WW53T (94.36 % 16S rRNA gene sequence similarity). On the basis of phenotypic, chemotaxonomic and phylogenetic data, strain MC 3624T represents a novel species of the genus Roseomonas, for which the name Roseomonas arcticisoli sp. nov. is proposed. The type strain is MC 3624T (=CCTCC AB 2014278T=LMG 28637T).

Undibacterium arcticum sp. nov., isolated from arctic alpine soil.

A Gram-stain-negative, aerobic, motile rod-shaped bacterium, designated 6-67T, was isolated from a soil sample collected from Longyearbyen, Svalbard. Its taxonomic position was investigated by genotypic, phenotypic and chemotaxonomic analyses. This isolate grew at 4-28 °C (optimum, 20 °C), at pH 5.0-9.0 (optimum, pH 7.0) and with 0-0.2 % (w/v) NaCl. Strain 6-67T contained Q-8 as a major respiratory quinone and MK-7 as a minor component; the major fatty acids were summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c) and C16 : 0. The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, two unidentified phospholipids and one unidentified aminophospholipid. The polyamines were putrescine and 2-hydroxyputrescine. 16S rRNA gene sequence analysis indicated that the novel strain 6-67T belonged to the family Oxalobacteraceae within the class Betaproteobacteria. The DNA G+C content of strain 6-67T was 56.21 mol%. On the basis of phylogenetic, physiological and chemotaxonomic data, strain 6-67T is considered to represent a novel species of the genus Undibacterium, for which the name Undibacterium arcticum sp. nov. is proposed. The type strain is 6-67T (=CCTCC AB 2015162T=KCTC 42986T).

Draft Genome Sequence of "Paramesorhizobium deserti" A-3-ET, a Strain Highly Resistant to Diverse ß-Lactam Antibiotics.

Here, we report the draft genome sequence of "Paramesorhizobium deserti" A-3-E(T), a strain isolated from the Taklimakan Desert of Xinjiang, China, which is resistant to multiple ß-lactam antibiotics and other antibiotics (kanamycin, erythromycin, streptomycin, etc.) as well.

Complete genome sequence of Kocuria flava strain HO-9041, a heavy metal removal bacterium from Xinjiang.

Kocuria flava HO-9041 isolated from the air of Xinjiang of China, is a Gram-positive, aerobic, coccoid, nonencapsulated, non-halophilic, and non-endospore-forming, in the genus Kocuria, and it shows the ability to remove heavy metal. Here, we report the finished and annotated genome sequence of this organism.

Pseudorhodobacter collinsensis sp. nov., isolated from a till sample of an icecap front.

A Gram-stain-negative, rod-shaped, aerobic and non-motile strain, designated 4-T-34T, was isolated from a till sample of Collins icecap front, Antarctica, and its taxonomic position was investigated by genotypic, phenotypic and chemotaxonomic analysis. The isolate grew at 4-30 °C (optimum 20-25 °C), at pH 6.0-10.0 and with 0-1.0 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain 4-T-34T belonged to the genus Pseudorhodobacter, with the closest relatives being Pseudorhodobacter wandonensis WT-MW11T (96.9 % 16S rRNA gene sequence similarity), Pseudorhodobacter antarcticus ZS3-33T (96.8 %), Pseudorhodobacter ferrugineus IAM 12616T (96.5 %) and Pseudorhodobacter aquimaris HDW-19T (95.4 %). Strain 4-T-34T contained Q-10 as the only ubiquinone and C18 : 1ω7c as the major fatty acid. The major polar lipids were phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, two unidentified aminophospholipids and two unidentified phospholipids. The DNA G+C content of strain 4-T-34T was 61 mol%. On the basis of phylogenetic, physiological and chemotaxonomic data, strain 4-T-34T is considered to represent a novel species of the genus Pseudorhodobacter, for which the name Pseudorhodobacter collinsensis sp. nov. is proposed. The type strain is 4-T-34T ( = CCTCC AB 2014005T = LMG 28256T).

Chryseobacterium frigidum sp. nov., isolated from high-Arctic tundra soil, and emended descriptions of Chryseobacterium bernardetii and Chryseobacterium taklimakanense.

A yellow, Gram-reaction-negative, non-motile, aerobic bacterium, designated D07T, was isolated from a tundra soil near Ny-Ålesund, Svalbard archipelago, Norway (78° N). Growth occurred at 4-37 °C (optimum 28-30 °C) and at pH 6.0-9.0 (optimum pH 7.0-8.0). The strain produced flexirubin-type pigments. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain D07T belonged to the genus Chryseobacterium in the family Flavobacteriaceae. The 16S rRNA gene sequence of this strain showed 93.83 and 93.31 % sequence similarity, respectively, to those of Chryseobacterium contaminans C26T and Chryseobacterium taklimakanense X-65T. Strain D07T contained anteiso-C15 : 0 (25.91 %), iso-C15 : 0 (16.05 %), iso-C16 : 0 3-OH (9.64 %), iso-C16 : 0 (9.42 %) and iso-C14 : 0 (7.36 %) as the predominant cellular fatty acids, MK-6 as the major respiratory quinone and phosphatidylethanolamine, five unknown aminolipids and three unknown lipids as the main polar lipids. The DNA G+C content was 49.3 mol%. On the basis of phenotypic, chemotaxonomic and phylogenetic data, strain D07T is considered to represent a novel species of the genus Chryseobacterium, for which the name Chryseobacterium frigidum sp. nov. is proposed. The type strain is D07T ( = CCTCC AB 2011160T = KCTC 42897T). Emended descriptions of Chryseobacterium bernardetii and Chryseobacterium taklimakanense are also provided.

Sphingoaurantiacus polygranulatus gen. nov., sp. nov., isolated from high-Arctic tundra soil, and emended descriptions of the genera Sandarakinorhabdus, Polymorphobacter and Rhizorhabdus and the species Sandarakinorhabdus limnophila, Rhizorhabdus argentea and Sphingomonas wittichii.

An orange, Gram-reaction-negative and aerobic bacterium, designated MC 3718T, was isolated from a tundra soil near Ny-Ålesund, Svalbard archipelago, Norway (78° N). The cells were motile with either a polar or a subpolar flagellum and reproduced by budding or asymmetrical cell division. Growth occurred at 4-37 °C (optimum 28-30 °C) and at pH 6.0-10.0 (optimum pH 9.0). Many cells accumulated poly-ß-hydroxybutyrate granules and contained a single large polyphosphate granule at a pole or in the middle of the cell. Cell walls contained meso-diaminopimelic acid as the diagnostic diamino acid, and ubiquinone 10 was the main respiratory quinone. Strain MC 3718T contained summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c; 29.49 %), summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c; 29.38 %), C17 : 1ω6c (10.15 %), C14 : 0 2-OH (9.05 %) and C16 : 0 (6.84 %) as the major cellular fatty acids. The main polar lipids were two sphingoglycolipids, phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, three unknown phospholipids and two unknown polar lipids. Carotenoids were detected. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain MC 3718T belonged to the family Sphingomonadaceae. The DNA G+C content was 67.2 mol%. On the basis of phenotypic, chemotaxonomic and phylogenetic data, strain MC 3718T is considered to represent a novel genus and species in the family Sphingomonadaceae, for which the name Sphingoaurantiacus polygranulatus gen. nov., sp. nov. is proposed. The type strain of Sphingoaurantiacus polygranulatus is MC 3718T ( = CCTCC AB 2014274T = LMG 28636T). Emended descriptions of the genera Sandarakinorhabdus, Polymorphobacter and Rhizorhabdus and the species Sandarakinorhabdus limnophila, Rhizorhabdus argentea and Sphingomonas wittichii are also provided.

Flavobacterium collinsense sp. nov., isolated from a till sample of an Antarctic glacier.

A novel rod-shaped, Gram-stain-negative, non-gliding and aerobic strain surrounded by a multilayer capsule, designated 4-T-2T, was isolated from a till sample of Collins glacier front, Antarctica. The bacterium formed yellow, circular, convex and smooth colonies. Growth occurred at 4-28 °C (optimum18-20 °C), at pH 7.0-10.0 (optimum pH 9.0) and with 0-1 % NaCl. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain 4-T-2T belonged to the genus Flavobacterium. Strain 4-T-2T shared the highest 16S rRNA gene sequence similarity with the type strain of Flavobacterium algicola (96.7 %). The DNA G+C content of strain 4-T-2T was 36.2 mol%. The only menaquinone was MK-6. The major cellular fatty acids were iso-C15 : 0, iso-C15 : 1 G, iso-C16 : 0 and summed feature 9 (comprising iso-C17 : 1ω9c and/or 10-methyl C16 : 0). Polar lipid profile consisted phosphatidylethanolamine, one unidentified aminolipid, one unidentified aminophospholipid and one unidentified lipid. On the basis of phylogenetic, physiological and chemotaxonomic data, strain 4-T-2T is considered to represent a novel species of the genus Flavobacterium, for which the name Flavobacterium collinsense sp. nov. is proposed. The type strain is 4-T-2T ( = CCTCC AB 2014004T = LMG 28257T).

Roseomonas arctica sp. nov., isolated from arctic glacial foreland soil.

A novel psychrotolerant bacterium, designed strain M6-79T, was isolated from an arctic glacial foreland soil sample collected from Ny-Ålesund in the Svalbard Archipelago, Norway. Cells of strain M6-79T were Gram-stain-negative, rod-shaped and produced a red-pigment. Strain M6-79T was strictly aerobic, non-motile, non-endospore-forming, oxidase-negative and catalase-positive. Based on 16S rRNA gene sequence analysis, strain M6-79T was phylogenetically related to Roseomonas aquatica TR53T (95.2 % 16S rRNA gene sequence similarity), Roseomonas lacus TH-G33T (94.3 %), 'Roseomonas sediminicola' FW-3 (94.3 %), Roseomonas terrae DS-48T (94.1 %) and Roseomonas soli 5N26T (94.1 %). The unique isoprenoid quinone detected in strain M6-79T was Q-9. The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, one unknown aminolipid and one unknown lipid. Strain M6-79T possessed C18 : 1ω7c, C16 : 0 and summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c) as the predominant fatty acids, and the DNA G+C content was 71.2 mol%. Combined data from phylogenetic, phenotypic and chemotaxonomic studies revealed that strain M6-79T represents a novel species of the genus Roseomonas, for which the name Roseomonas arctica sp. nov. is proposed. The type strain is strain M6-79T ( = CCTCC AB 2013101T = LMG 28251T).

Effects of Space Environment on Genome, Transcriptome, and Proteome of Klebsiella pneumoniae.

BACKGROUND AND AIMS: The aim of this study was to explore the effects of space flight on Klebsiella pneumoniae. METHODS: A strain of K. pneumoniae was sent to space for 398 h aboard the ShenZhou VIII spacecraft during November 1, 2011-November 17, 2011. At the same time, a ground simulation with similar temperature conditions during the space flight was performed as a control. After the space mission, the flight and control strains were analyzed using phenotypic, genomic, transcriptomic and proteomic techniques. RESULTS: The flight strains LCT-KP289 exhibited a higher cotrimoxazole resistance level and changes in metabolism relative to the ground control strain LCT-KP214. After the space flight, 73 SNPs and a plasmid copy number variation were identified in the flight strain. Based on the transcriptomic analysis, there are 232 upregulated and 1879 downregulated genes, of which almost all were for metabolism. Proteomic analysis revealed that there were 57 upregulated and 125 downregulated proteins. These differentially expressed proteins had several functions that included energy production and conversion, carbohydrate transport and metabolism, translation, ribosomal structure and biogenesis, posttranslational modification, protein turnover, and chaperone functions. At a systems biology level, the ytfG gene had a synonymous mutation that resulted in significantly downregulated expression at both transcriptomic and proteomic levels. CONCLUSIONS: The mutation of the ytfG gene may influence fructose and mannose metabolic processes of K. pneumoniae during space flight, which may be beneficial to the field of space microbiology, providing potential therapeutic strategies to combat or prevent infection in astronauts.

Unraveling adaptation of Pontibacter korlensis to radiation and infertility in desert through complete genome and comparative transcriptomic analysis.

The desert is a harsh habitat for flora and microbial life due to its aridness and strong radiation. In this study, we constructed the first complete and deeply annotated genome of the genus Pontibacter (Pontibacter korlensis X14-1(T) = CCTCC AB 206081(T), X14-1). Reconstruction of the sugar metabolism process indicated that strain X14-1 can utilize diverse sugars, including cellulose, starch and sucrose; this result is consistent with previous experiments. Strain X14-1 is also able to resist desiccation and radiation in the desert through well-armed systems related to DNA repair, radical oxygen species (ROS) detoxification and the OstAB and TreYZ pathways for trehalose synthesis. A comparative transcriptomic analysis under gamma radiation revealed that strain X14-1 presents high-efficacy operating responses to radiation, including the robust expression of catalase and the manganese transport protein. Evaluation of 73 novel genes that are differentially expressed showed that some of these genes may contribute to the strain's adaptation to radiation and desiccation through ferric transport and preservation.

Risungbinella pyongyangensis gen. nov., sp. nov., a mesophilic member of the family Thermoactinomycetaceae isolated from an agricultural soil sample.

A mesophilic strain, designed MC 210T, was isolated from an agricultural soil sample from Pyongyang, Democratic People's Republic of Korea, and its taxonomic position was investigated by using a polyphasic approach. The novel strain grew well on PYI medium, and no diffusible pigments were produced. The optimum temperature for growth was 37 °C. The aerial mycelium was well developed, but not fragmented. The strain was Gram-reaction-positive and non-motile and formed endospores on the aerial mycelium. Phylogenetic analysis based on the 16S rRNA gene sequence indicated that strain MC 210T belongs to the family Thermoactinomycetaceae. Strain MC 210T showed 16S rRNA gene sequence similarities of 92.90 and 92.54% to the type strains of Geothermomicrobium terrae and Shimazuella kribbensis, respectively. The cell wall of strain MC 210T contained meso-diaminopimelic acid, glutamic acid and alanine as the diagnostic amino acids, and whole-cell hydrolysates contained glucose, arabinose and galactose. Strain MC 210T contained anteiso-C13 : 0, iso-C14 : 0, C14 : 0, anteiso-C15 : 0, C16 : 0 and iso-C13 : 0 as the major cellular fatty acids. The main polar lipids were phosphatidylethanolamine, phosphatidylmethylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, two unknown aminophospholipids, an unknown aminolipid, three unknown phospholipids and five unknown polar lipids. The predominant menaquinone was MK-7.The G+C content of the genomic DNA was 42.1 mol%. On the basis of our phylogenetic, physiological and chemotaxonomic data, strain MC 210T is considered to represent a novel genus and species, for which we propose the name Risungbinella pyongyangensis gen. nov., sp. nov., in the family Thermoactinomycetaceae. The type strain of Risungbinella pyongyangensis is MC 210T (CCTCC AA 2013021T = NRRL B-59118T).