Major Fatty Acids Research Articles

Thermobacterium salinum gen. nov., sp. nov., a novel member of the family Flavobacteriaceae isolated from a hydrothermal zone.

A Gram-stain-negative, aerobic, non-motile and rod-shaped bacterial strain, designated as strain TK19130T, was isolated from the Lonqi hydrothermal zone in the Southwest Indian Ridge. Growth occurred with 1-12 % (w/v) NaCl (optimum, 2-4 %), at 10-40 °C (optimum, 30-35 °C) and at pH 6.0-9.0 (optimum, pH 7.0-8.0). The genome of strain TK19130T was 3.15 Mb, with a DNA G+C content of 41.35 %. Based on the results of 16S rRNA gene sequence analysis, strain TK19130T was affiliated with the family Flavobacteriaceae, in which the highest similarity was 90.54 % to Aureisphaera salina A6D-50T, under the genus demarcation boundary (94.50 %). Average nucleotide identity values between strain TK19130T and adjacent strains were 67.17-72.00 %, lower than the recommended threshold of 73.98 % for genus delineation. The predominant respiratory quinone of strain TK19130T was menaquinone 6. Major polar lipids were phosphatidylethanolamine, three aminolipids and one unidentified polar lipid. Major fatty acids were detected as iso-C15 : 1 G, iso-C15 : 0 and iso-C17 : 0 3-OH. Based on the polyphasic taxonomic evidence presented above, strain TK19130T formed an independent branch representing a new species of a novel genus within the family Flavobacteriaceae, for which the name Thermobacterium salinum gen. nov., sp. nov. is proposed. The type strain is TK19130T (=CGMCC 1.18993T=JCM 35842T=MCCC M28200T).

Neopusillimonas aromaticivorans sp. nov. isolated from poultry manure.

A polyphasic taxonomic approach was used to characterize a novel bacterium, designated strain CC-YST667T, isolated from poultry manure sampled in Taiwan. The cells were observed to be aerobic, motile and non-spore-forming rods, displaying positive reactions for oxidase. Optimal growth of CC-YST667T was observed at 25 °C, pH 8.0 and with 1 % (w/v) NaCl. The polar lipid profile consisted of phosphatidylmonomethylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine and multiple unidentified polar lipids. The major polyamine was spermidine. The major cellular fatty acids (>5 %) included C16 : 0, C17 : 0cyclo, C19 : 0cyclo ω8c and C14 : 0 3OH/iso-C16 : 1 I. On the basis of the results of analysis of 16S rRNA gene sequences, this isolate showed the closest phylogenetic relationship with 'Neopusillimonas minor' (with 98.2 % similarity) and Paralcaligenes ureilyticus (with 97.3 % similarity) of the family Alcaligenaceae. The draft genome, (3.3 Mb) with a DNA G+C content of 57.2 mol%, harboured various genes involved in the biodegradation of aromatic hydrocarbons. CC-YST667T shared highest orthologous average nucleotide identity (OrthoANI) with the type strains of species of of the genera Neopusillimonas (72.4‒77.9 %, n=2), Pusillimonas (72.8‒73.0 %, n=2) and Pollutimonas (71.7‒73.0 %, n=5). On the basis of its distinct phylogenetic, phenotypic and chemotaxonomic traits together with the results of comparative 16S rRNA gene sequencing, OrthoANI, digital DNA-DNA hybridization (DDH) and the phylogenomic placement, strain CC-YST667T is considered to represent a novel species of the genus Neopusillimonas, for which the name Neopusillimonas aromaticivorans sp. nov. is proposed. The type strain is CC-YST667T (=BCRC 81321T =JCM 34761T).

Nutritional Composition and Odor-Contributing Volatile Compounds of the Edible Mushroom Cantharellus alborufescens.

Chanterelles are one of the most highly valued wild edible mushroom genera worldwide. This work aimed to investigate the nutritional characteristics and volatile compounds' profile of Cantharellus alborufescens for the first time. Proximate analysis was performed according to the Association of Official Agricultural Chemists, while the mineral contents and the volatile compounds were determined using ICP-MS and GC-MS, respectively. C. alborufescens had an average of 25.8% protein, 5.5% fat, 12.7% ash, and 55.9% carbohydrates, including 11.4% fiber per dw of mushroom. Further analyses of the fat and protein contents revealed high amounts of polyunsaturated fatty acids as well as monosodium glutamate-like amino acids. Linoleic acid (42.0% of fat) and oleic acid (28.6% of fat) were the major fatty acids, while leucine (1.2%) and lysine (0.9%) were the most abundant essential amino acids. The results showed that C. alborufescens contained 3.1 µg/g vitamin D2 and 4.9 mg/g vitamin E per dw, as well as notable quantities of macro- and microelements, such as potassium, calcium, magnesium, and iron. GC-MS analysis revealed various volatile compounds such as acetaldehyde, n-hexanal, 3-methylbutanal, 1-octen-3-ol, etc. In conclusion, this study supports the use of C. alborufescens as a food rich in fiber and vitamin E, with a suitable amount of protein and other nutrients.

Moringa oleifera and Ruta angustifolia fixed oils and a prospective method to obstruct pupal development in cotton leafworm

The cotton leafworm, Spodoptera littoralis, is a polyphagous pest that attacks various economic crops. Integrated Pest Management (IPM) uses different techniques to combat this pest unfortunately chemical control is the predominant. However, it does not target the pupal stage of the insect. Therefore, a safe and cost-effective technique must be developed to address this issue.This technique integrates using plant-based agents; M. oleifera and R. angustifolia seed oils as pupaicids. Various concentrations (1%, 2%, and 4%) of both oils were employed by means of the dipping method of pre-pupae. The study delved into the biological, and biochemical aspects of pupal development to adult emergence. Analysis of the fatty acids along with the hydrocarbons and sterols was conducted through GLC analysis for oils composition.Our research has shown that Moringa oleifera and Ruta angustifolia oils at a concentration of 4 % have a significant impact on pre-pupal mortality (42.57& 61.9 %) and pupation of survival pre-pupa (57.42&38.09 %) However, emerged adults were reduced to 83.33 % and 60 %, respectively. Chitinase recording significantly disturbance after 1 day for Ruta (6.21 µg/min/g) and Moringa oil (2.12 µg/min/g). Also, Phosphatase enzyme showed a significant disturbance after 4 and 7 days of treatments. GLC data of fatty acids showed that oleic acid (74.42 %) was the major fatty acid in M. oleifera oil, while linolenic, linoleic, and oleic acids represented 31.39 %, 22.70 %, and 21.95 %, respectively, in R. angustifolia oil. Sterols in M. oleifera oil were β-sitosterol and stigmasterol, while Ruta oil contained additional amounts of cholesterol and campesterol,Briefly, the suggested technique was effective in disturbing pupal development and reducing emerged adults. Ruta was more effective than Moringa oil due to its contents of sterols and hydrocarbons that may affect ecdysis.

Ligilactobacillus cholophilus sp. nov., isolated from pickled potherb mustard (Brassica juncea Coss.).

Strain BD7642T was isolated from Chinese pickled potherb mustard (Brassica juncea Coss.) purchased from a local market in Shanghai, PR China. A polyphasic approach, including 16S rRNA gene sequence, housekeeping gene, average nucleotide identity (ANI), digital DNA-DNA hybridization (dDDH), G+C content and phenotypic analyses, was employed to characterize strain BD7642T. Cells of the bacterium were short round rods, Gram-stain-positive, non-spore-forming and catalase-negative. The strain grew at 30-45 °C and pH 4.0-8.0. Optimum growth occurred at 35-40 °C and pH 6.0-7.0. The strain exhibited growth with salt (NaCl) concentrations of up to 5 % (w/v). The G+C content of the strain's genomic DNA was 31.37 mol%. The major fatty acids were C16 : 0, C18 : 1 c9 and summed feature 10 (C18 : 1 c11/t9/t6). 16S rRNA gene sequencing revealed that strain BD7642T represents a member of the genus Ligilactobacillus and it had high sequence similarity to Ligilactobacillus aviarius NBRC 102162T (96.73 %), Ligilactobacillus araffinosus LGM 23560 (96.66 %) and Ligilactobacillus salivarius JCM 1231T (95.82 %). The dDDH values between strain BD7642T and its phylogenetically related species within the genus Ligilactobacillus ranged from 12.6 to 25.4 %. The ANI values between strain BD7642T and its closely related taxa were far lower than the threshold (95 %-96 %) used for species differentiation. Results of phylogenetic, physiological and phenotypic characterization confirmed that strain BD7642T represents a novel species within the genus Ligilactobacillus, for which the name Ligilactobacillus cholophilus sp. nov. is proposed. The type strain is BD7642T (=CCTCC AB 2022398T=JCM 36074T).

Robiginitalea aurantiaca sp. nov. and Algoriphagus sediminis sp. nov., isolated from coastal sediment.

Two novel rod-shaped, Gram-stain-negative, aerobic and non-motile bacterial strains, designated M39T and C2-7T, were isolated from the coastal sediment of Xiaoshi Island, Weihai, PR China. Growth of strain M39T occurred at 15-37 °C, at pH 6.0-9.0 and in the presence of 1.0-9.0 % (w/v) NaCl. Strain C2-7T grew at 15-40 °C, at pH 6.0-8.0 and in the presence of 0.5-8.0 % (w/v) NaCl. Phylogenetic analysis based 16S rRNA gene sequences revealed that strains M39T and C2-7T belong to the phylum Bacteroidota. Based on the results of 16S rRNA gene sequence analysis, the closest relative of strain M39T was Robiginitalea marina KCTC 92035T (95.4 %), and the closest relative of strain C2-7T was Algoriphagus namhaensis DPG-3T (97.0 %). The percentage of conserved protein and average nucleotide identity values between strain M39T and some species of the genus Robiginitalea were 66.9-77.6% and 69.3-71.0 %, respectively, while those between strain C2-7T and some species of the genus Algoriphagus were 68.0-70.1% and 56.1-72.6 %, respectively. The major cellular fatty acids (>10 %) of strain M39T consisted of iso-C15 : 1 F, iso-C15 : 0 and iso-C17 : 0 3-OH, while those of strain C2-7T were iso-C15 : 0 and C16 : 1 ω7c/C16 : 1 ω6c. MK-6 was the only respiratory quinone that was compatible with the genus of strain M39T. The predominant menaquinone of strain C2-7T was MK-7. The major polar lipids of strain M39T were phosphatidylethanolamine and glycolipids, and those of strain C2-7T were phosphatidylethanolamine, one unidentified aminolipid and four unidentified lipids. The DNA G+C contents of strains M39T and C2-7T were 46.9 and 40.8 mol%, respectively. Based upon the results presented in this study, strains M39T and C2-7T represent novel species of the genera Robiginitalea and Algoriphagus, respectively, for which the names Robiginitalea aurantiaca sp. nov. and Algoriphagus sediminis sp. nov. are proposed with the type strains M39T (=MCCC 1H00498T=KCTC 92014T) and C2-7T (=MCCC 1H00414T=KCTC 92027T).

Lysinibacillus irui sp. nov., isolated from Iru, fermented African locust beans.

A Gram-positive, motile, aerobic, rod-shaped, endospore-forming strain designated IRB4-01T was isolated from fermented African locust beans (Iru) obtained from Bodija market in the city of Ibadan, southwestern Nigeria, during a screening process from food-related sources. IRB4-01T grew at 10-50 °C (optimum, 35-37 °C), pH 6-10 (optimum, pH 7) and in 0-6 % NaCl (optimum, 1-3 %). Phylogenetic analyses based on 16S rRNA and combined short- and long-read genome sequencing revealed that IRB4-01T is closely related to Lysinibacillus cavernae SYSU K30005T and Lysinibacillus boronitolerans 10aT. The cell-wall peptidoglycan type was A4α (Lys-Asp), containing the diagnostic diamino acid lysine. The major polar lipids in strain IRB4-01T were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol and an unidentified phospholipid, while the predominant menaquinone was MK-7. The major cellular fatty acids were iso-C15 : 0, anteiso-C15 : 0 and iso-C16 : 0. Genomic DNA G+C content was 37.4 mol%, while the digital DNA-DNA hybridization revealed 33.6 and 32.3 % relatedness to L. cavernae SYSU K30005T and L. boronitolerans 10aT, respectively. Based on phenotypic, physiological and chemotaxonomic characteristics, as well as genome comparisons, strain IRB4-01T represents a novel species of the genus Lysinibacillus, for which the name Lysinibacillus irui sp. nov. is proposed. The type strain is IRB4-01T (NCIMB 15452T=LMG 32887T). Hybrid genome data are provided on the NCBI database using the Bioproject number PRJNA906010 and accession numbers CP113527 and CP113528. Additionally, a representative 16S rRNA sequence is available with the GenBank accession number OQ566940.

Curtobacterium caseinilyticum sp. nov., Curtobacterium subtropicum sp. nov. and Curtobacterium citri sp. nov., isolated from citrus phyllosphere.

Three novel Gram-stain-positive, aerobic and rod-shaped bacterial strains, designated RHCKG28T, RHCJP20T and RHCKG23T, were isolated from phyllosphere of healthy citrus leaves collected from Renhua County in Guangdong Province, PR China. 16S rRNA gene sequences comparison and phylogenetic analyses showed that they all belonged to the genus Curtobacterium, among which strain RHCKG28T showed the highest similarity to Curtobacterium herbarum NBRC 103064T (99.3 %), while strains RHCJP20T and RHCKG23T showed 99.2 and 99.0 % similarity to Curtobacterium citreum JCM 1345T, respectively. Phylogenomic analysis showed that the three novel strains were most closely related to C. citreum JCM 1345T and Curtobacterium albidum JCM 1344T. The novel strains could be distinguished from their closely related type strains in terms of enzyme activities, substrate assimilation and fatty acid profiles. In addition, the average nucleotide identity and digital DNA-DNA hybridization values between the novel strains and closely related type strains were 84.4‒89.5 % and 24.5‒34.1 %, respectively, which were below the threshold values for species delimitation. They all took anteiso-C15 : 0, iso-C16 : 0 and anteiso-C17 : 0 as the major fatty acids, menaquinone 9 (MK-9) as the sole predominant respiratory quinone, and ornithine as the principal cell-wall diamino acid. The major polar lipids consisted of phosphatidylglycerol, diphosphatidylglycerol and several unidentified glycolipids. The phenotypic, genotypic and chemotaxonomic data supported that they represent three distinct novel species of the genus Curtobacterium, for which the names Curtobacterium caseinilyticum sp. nov., Curtobacterium subtropicum sp. nov. and Curtobacterium citri sp. nov. are proposed, with RHCKG28T (=GDMCC 1.2667T=JCM 34828T), RHCJP20T (=GDMCC 1.2668T=JCM 34829T) and RHCKG23T (=GDMCC 1.2669T=JCM 34830T) as the type strains, respectively.

Isolation and characterization of Pinibacter soli sp. nov., and in silico genome mining of Pinibacter for biosynthetic gene cluster prediction

A Gram-stain-negative, aerobic, rod-shaped, non-motile and non-flagellated novel bacterial strain, designated MAH-24T, was isolated from the rhizospheric soil of a pine garden. The colonies were observed to be orange-coloured, smooth, spherical and 0.4–0.8 mm in diameter when grown on Reasoner's 2A agar medium for 2 days. Strain MAH-24T was found to be able to grow at 10–35 °C, at pH 6.0–9.0 and in the presence of 0–1.0 % NaCl (w/v). The strain was found to be positive for the catalase and oxidase tests. The strain was positive for hydrolysis of aesculin and l-tyrosine. According to the 16S rRNA gene sequence comparisons, the isolate was identified as a member of the genus Pinibacter and to be closely related to Pinibacter aurantiacus MAH-26T (99.2 % sequence similarity). The novel strain MAH-24T has a draft genome size of 5 918 133 bp (13 contigs), annotated with 4613 protein-coding genes, 47 tRNA and three rRNA genes. The average nucleotide identity (ANI) and digital DNA–DNA hybridization (dDDH) values between strain MAH-24T and the closest type strain P. aurantiacus MAH-26T were in the range of 85.3 and 29.9 %, respectively. In silico genome mining revealed that both novel strain MAH-24T and P. aurantiacus MAH-26T have a significant potential for the production of novel natural products in the future. The genomic DNA G+C content was determined to be 41.0 mol%. The predominant isoprenoid quinone was menaquinone-7. The major fatty acids were identified as C15:0 iso, C15:1 iso G and C17:0 iso 3OH. On the basis of dDDH, ANI, genotypic, chemotaxonomic and physiological data, strain MAH-24T represents a novel species within the genus Pinibacter , for which the name Pinibacter soli sp. nov. is proposed, with MAH-24T (=KACC 19747T=CGMCC 1.13659T) as the type strain.

Pan-Genome Analyses of the Genus Cohnella and Proposal of the Novel Species Cohnella silvisoli sp. nov., Isolated from Forest Soil.

Two strains, designated NL03-T5T and NL03-T5-1, were isolated from a soil sample collected from the Nanling National Forests, Guangdong Province, PR China. The two strains were Gram-stain-positive, aerobic, rod-shaped and had lophotrichous flagellation. Strain NL03-T5T could secrete extracellular mucus whereas NL03-T5-1 could not. Phylogenetic analysis based on 16S rRNA gene sequences revealed that the two strains belong to the genus Cohnella, were most closely related to Cohnella lupini LMG 27416T (95.9% and 96.1% similarities), and both showed 94.0% similarity with Cohnella arctica NRRL B-59459T, respectively. The two strains showed 99.8% 16S rRNA gene sequence similarity between them. The draft genome size of strain NL03-T5T was 7.44 Mbp with a DNA G+C content of 49.2 mol%. The average nucleotide identities (ANI) and the digital DNA-DNA hybridization (dDDH) values between NL03-T5T and NL03-T5-1 were 99.98% and 100%, indicating the two strains were of the same species. Additionally, the ANI and dDDH values between NL03-T5T and C. lupini LMG 27416T were 76.1% and 20.4%, respectively. The major cellular fatty acids of strain NL03-T5T included anteiso-C15:0 and iso-C16:0. The major polar lipids and predominant respiratory quinone were diphosphatidylglycerol (DPG) and menaquinone-7 (MK-7). Based on phylogenetic analysis, phenotypic and chemotaxonomic characterization, genomic DNA G+C content, and ANI and dDDH values, strains NL03-T5T and NL03-T5-1 represent novel species in the genus Cohnella, for which the name Cohnella silvisoli is proposed. The type strain is NL03-T5T (=GDMCC 1.2294T = JCM 34999T). Furthermore, comparative genomics revealed that the genus Cohnella had an open pan-genome. The pan-genome of 29 Cohnella strains contained 41,356 gene families, and the number of strain-specific genes ranged from 6 to 1649. The results may explain the good adaptability of the Cohnella strains to different habitats at the genetic level.

Streptomyces changanensis sp. nov. Isolated from Soil in China.

An aerobic, Gram-positive, and non-motile actinomycete, designated HL-66T, was isolated from a soil sample collected in the Meridian Valley, Shaanxi Province, China. Morphological, chemotaxonomic, and phylogenetic characteristics showed a high similarity to the genus Streptomyces. Based on 16S rRNA gene sequence analysis, the closest phylogenetic neighbour of HL-66T were Streptomyces lavendofoliae NBRC 12882T (99.17%), Streptomyces gobitricini NBRC 15419T (99.03%) and Streptomyces roseolilacinus NBRC 12815T (98.96%). Genome relatedness indexes revealed that the average nucleotide identity and digital DNA-DNA hybridization values between HL-66T and its closest phylogenomic relative (S. roseolilacinus JCM 4335T) were 88.61% and 32.10%, respectively. The cell-wall peptidoglycan contains LL-diaminopimelic acid. Predominant menaquinones are MK-9 (H6), MK-9(H4) and MK-9(H8). The major cellular fatty acids were iso-C16:0, anteiso-C15:0, iso-C16:1 H, and C16:1 ω7c. The polar lipid pattern consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol, phosphatidylinositol mannosides, and an unknown phospholipid. Based on phylogenetic analyses, genome-genome distance calculation, and average nucleotide identity, strain HL-66T represents a novel species of the genus Streptomyces. Therefore, a new species Streptomyces changanensis sp. nov. is proposed with strain HL-66T (= CGMCC 22674 = JCM 35800) as the type strain.

Biotechnological production of omega-3 fatty acids: current status and future perspectives.

Omega-3 fatty acids, including alpha-linolenic acids (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), have shown major health benefits, but the human body's inability to synthesize them has led to the necessity of dietary intake of the products. The omega-3 fatty acid market has grown significantly, with a global market from an estimated USD 2.10 billion in 2020 to a predicted nearly USD 3.61 billion in 2028. However, obtaining a sufficient supply of high-quality and stable omega-3 fatty acids can be challenging. Currently, fish oil serves as the primary source of omega-3 fatty acids in the market, but it has several drawbacks, including high cost, inconsistent product quality, and major uncertainties in its sustainability and ecological impact. Other significant sources of omega-3 fatty acids include plants and microalgae fermentation, but they face similar challenges in reducing manufacturing costs and improving product quality and sustainability. With the advances in synthetic biology, biotechnological production of omega-3 fatty acids via engineered microbial cell factories still offers the best solution to provide a more stable, sustainable, and affordable source of omega-3 fatty acids by overcoming the major issues associated with conventional sources. This review summarizes the current status, key challenges, and future perspectives for the biotechnological production of major omega-3 fatty acids.

Tumebacillus lacus sp. nov., isolated from lake water.

A Gram-stain-positive, aerobic, rod-shaped, endospore-forming and motile, by means of peritrichous flagella, bacterium, designated DT12T, was isolated from a lake water sample from Datun Lake of Yunnan Province, PR China. The results of phylogenetic analysis based on 16S rRNA gene sequence and the concatenated alignment of 120 ubiquitous single-copy proteins indicated that the novel strain represented a member of the genus Tumebacillus. The sole quinone was menaquinone-7 and the cell-wall peptidoglycan was type-A1γ. The major fatty acids (>10 %) of the novel strain were iso-C15 : 0 and anteiso-C15 : 0, while the major polar lipids were phosphatidylmonomethylethanolamine, phosphatidylethanolamine and phosphatidylglycerol. The results of phylogenetic analyses combined with phylogenetic, phenotypic and chemotaxonomic features, strongly supported the hypothesis that the strain should be classified as representing a novel species of the genus Tumebacillus, for which the name Tumebacillus lacus sp. nov. is proposed. The type strain is DT12T (=KCTC 33958T= MCCC 1H00320T). The genomic analysis revealed that DT12T has various biosynthetic gene clusters for secondary metabolites, and members of the genus Tumebacillus may represent a promising source of new natural products. Our study also showed that members of the genus Tumebacillus are widely distributed in a variety of habitats throughout the globe, particularly in soils, human-, animal- and plant-associated environments. Members of the genus Tumebacillus may have an important role in the growth and health of humans, plants and animals.

PSI-20 Trans Vaccenic Acid Does Not Improve Insulin Resistance in Diet Induced Obese Mice

Abstract Trans vaccenic acid (TVA, trans11-18:1) is a natural trans fatty acid that is exclusively found in ruminant fats such as dairy, beef, and lamb. Increased circulating concentrations of TVA and its metabolites are epidemiologically related to a reduced risk of insulin resistance and type 2 diabetes (T2D). However, direct causative evidence is lacking, and the mechanisms are poorly understood. The objective of this study was to evaluate whether TVA can alleviate insulin resistance in diet-induced obese mice when compared with oleic acid (OA, cis9-18:1, the major dietary cis 18:1 isomer) or trans10-18:1 (a major industrial trans fatty acid isomer). Forty-eight male C57BL/6J mice (7 weeks old) were fed either a low-fat diet (LFD,10% kcal total fat), a high-fat diet (HFD) enriched with OA (HFD-OA; 45% kcal total fat, 6% kcal from pure OA), an HFD enriched with TVA (HFD-TVA; 45% kcal total fat, 6% kcal from pure TVA), or an HFD enriched with trans-10 18:1 (HFD-T10; 45% kcal total fat, 6% kcal from pure trans-10 18:1) for 19 weeks. The metabolic phenotype was characterized using a glucose tolerance test (GTT) and insulin tolerance test (ITT). Insulin-sensitive tissues (muscle, liver, and adipose) were harvested and extracted for protein, which was analyzed for protein kinase B (Akt) and phosphorylated Akt (pAKT) by western blot using Vinculin as a loading control. The resulting band intensities were quantitated using the FluorChem 9900 program (Alpha Innotech). pAkt expression was normalized to Akt. Data were analyzed using one-way analysis of variance (ANOVA) followed by Tukey’s test. Our GTT results suggested a greater (P < 0.05) glucose intolerance in both HFD-TVA and HFD-T10 groups compared with the LFD group. Whereas HFD-OA-fed mice maintained their glucose tolerance and insulin sensitivity despite greater body weight and adiposity. In agreement with GTT and ITT results, we found reduced (P < 0.05) Akt phosphorylation in the muscle of both HFD-TVA and HFD-T10 groups compared with LFD while there was no difference in phosphorylation level in the liver and adipose. In conclusion, this work demonstrates that contrary to our initial hypothesis, a large dose of TVA (6% of calorie intake) promotes glucose intolerance and insulin resistance in HFD-fed mice. Further studies using the typical intake of TVA in humans (0.5 to 1% of calorie intake) are required to better understand the effects of TVA on glucose homeostasis.

Two novel alkalitolerant species Pseudalkalibacillus spartinae sp. nov. and Pseudalkalibacillus sedimenti sp. nov.

In this study, two novel alkalitolerant strains (FJAT-53046T and FJAT-53715T) were isolated from sediment samples collected in Zhangzhou, PR China. Phylogeny based on 16S rRNA gene sequences suggested that strains FJAT-53046T and FJAT-53715T were new members of the genus Pseudalkalibacillus. The two novel strains showed the highest 16S rRNA gene sequence similarity to Pseudalkalibacillus hwajinpoensis DSM 16206T, with values of 97.4 and 97.6 %, respectively. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between the two strains and the reference strain were 77.2 and 79.6 %, 20.9 and 30.2 %, respectively, which were below the prokaryotic species delineation thresholds. The ANI and dDDH values between strains FJAT-53046T and FJAT-53715T were 86.0 and 30.2 %, respectively, suggesting that they belonged to different species in the genus Pseudalkalibacillus. The major respiratory quinone in both strains was MK-7 and the major cellular fatty acids were anteiso-C15 : 0 and anteiso-C17 : 0. Diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine were the major polar lipids in both novel strains. Combined with results stemming from the determination of physical and biochemical characteristics, chemical properties, and genome analysis, strains FJAT-53046T and FJAT-53715T are proposed to represent two novel species of the genus Pseudalkalibacillus, for which the names Pseudalkalibacillus spartinae sp. nov. and Pseudalkalibacillus sedimenti sp. nov. are proposed. The type strains are FJAT-53046T (=GDMCC 1.3077T=JCM 35611T) and FJAT-53715T (=GDMCC 1.3076T=JCM 35610T), respectively.

Alteriqipengyuania flavescens sp. nov., isolated from Pearl River Estuary sediment.

Two Gram-stain-negative, aerobic, rod-shaped, non-motile and golden yellow pigmented bacteria, designated as SCSIO 75105T and SCSIO 75732, were isolated from sediment in the Pearl River Estuary, Guangdong Province, PR China. Cells were positive for catalase and oxidase. Growth occurred at 10-37 °C (optimum, 28 °C), pH 6.0-10.0 (optimum, pH 7.0) and 0-5.0 % (w/v) NaCl (optimum, 2.0-3.0 %). The 16S rRNA gene analysis indicated that these two isolates shared a similarity of 100 % each other. The 16S rRNA gene sequence analysis indicated that these two isolates showed highest similarity to Altererythrobacter ishigakiensis CGMCC 1.14979T (97.3 %). However, a phylogenetic tree based on 288 orthologous clusters indicated that these two isolates were closely related to Alteriqipengyuania halimionae CPA5T. The average nucleotide identity, average amino acid identity, digital DNA-DNA hybridization and evolutionary distance values between the two isolates and Alteriqipengyuania halimionae CPA5T were 73.7-74.0 %, 65.2 %, 19.5 % and 0.24, respectively. The genomic DNA G+C content of both isolates was 65.2 mol%. The major cellular fatty acids were C18 : 1 ω7c, C17 : 1 ω6c and summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c), and Q-10 was the respiratory quinone. The polar lipid profile contained diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, sphingoglycolipid and one unidentified glycolipid. On the basis of the results of phenotypic, physiological, chemotaxonomic and genotypic characterization, strains SCSIO 75105T and SCSIO 75732 are considered to represent a novel species in the genus Alteriqipengyuania, for which the name Alteriqipengyuania flavescens sp. nov. is proposed. The type strain is SCSIO 75105T (=KCTC 92502T=MCCC 1K07993T).

Metformin-Induced Ferroptosis Is a Therapeutic Vulnerability in IDH2-Mutant AML Linked to Metabolic Rewiring Towards Fatty Acid Oxidation

Metabolic rewiring is an essential feature of leukemic cells to sustain tumorigenesis and is largely influenced by mutational status. We previously demonstrated this phenomenon in FLT3-ITD acute myeloid leukemia (AML) upon combined inhibition of complex II activity and lactate import (Erdem et al., 2022). Mutations in isocitrate dehydrogenase ( IDH1/2mut) occur in about 20% of AML cases, and despite the emergence of targeted therapies, patients often relapse. The molecular and epigenetic outcomes of 2-R-hydroxyglutarate accumulation and competitive inhibition of histone demethylases have been extensively studied in IDH1/2mut AMLs, but the metabolic consequences are still largely unexplored. Here, we applied multi-omics studies on cell line models and primary AML samples combined with functional studies to unravel the metabolic rewiring of IDH1/2mut AMLs. Transcriptional characterization of isogenic TF1 wt and IDH2R140Q cell lines (10978 genes) revealed increased expression of CD36, a major fatty acid (FA) transporter, and gene set enrichment analysis (GSEA) associated IDH2R140Q cells with terms related to FA processes and activity of mitochondrial complex I. Quantitative metabolome analysis of TF1 wt and IDH2R140Q (180 metabolites) revealed lower levels of acylcarnitines of variable carbon lengths, suggesting increased FA oxidation, and upregulation of glycerophospholipid and glycerolipid metabolism in IDH2R140Q cells. Next, we validated our findings by performing a metabolomic profiling (172 metabolites) on primary AML samples (n=26, including 4 IDH1mut and 2 IDH2mut), for which label-free quantitative proteome data (11272 proteins) was also generated. Proteome analysis confirmed increased CD36 expression and enrichment for FA and mitochondrial processes in IDH1/2mut patients. In line, metabolome data also revealed increased oxidation of branched-chain FAs in this sample group. Altogether, these findings suggested a profound disturbance in lipid metabolism and supported the notion that IDH1/2 mutant cells rely on mitochondrial respiration, whereby FAs seem to be the preferred carbon source. Next, we performed an in vitro drug screen targeting the main metabolic pathways, which revealed increased sensitivity of IDH2R140Q cells to the FDA-approved complex I inhibitor metformin. Extracellular flux analysis indicated no significant difference in the oxygen consumption rate (OCR) between TF1 wt and IDH2R140Q upon metformin treatment, while the viability of mutant cells was significantly diminished. Contrarily, the basal extracellular acidification rate (ECAR) was increased in TF1 wt cells upon complex I inhibition, suggesting that these cells rewire their metabolism towards glycolysis more efficiently than mutant cells. Furthermore, we knocked down CD36 expression to investigate whether disrupting lipid metabolism in IDH2R140Q cells would constitute a metabolic vulnerability. Notably, CD36 knockdown resulted in increased resistance to metformin in IDH2R140Q cells. These data suggested that enhanced lipid uptake mediated by CD36 in IDH2R140Q cells not only boosts OCR but may also disrupt lipid homeostasis, causing cells to become more susceptible to lipid peroxidation. Since the role of metformin-induced ferroptosis in AML is still unclear, we performed an RNA-seq analysis on TF1 wt and IDH2R140Q cells treated with metformin (5 mM) for 72 hours (10326 genes). Single-sample GSEA associated the transcriptome of metformin-treated cells with ferroptosis signatures in both cell lines but to a significantly higher extent in IDH2R140Q. We functionally validated this finding by using the BODIPY C11 probe, a lipid peroxidation sensor. After 24h of metformin treatment, both TF1 wt and IDH2R140Q displayed increased lipid ROS. Lipid peroxidation levels were further enhanced by combining metformin with palmitate, a saturated FA, supporting the notion that elevated lipid availability and uptake may increase cell death via ferroptosis. Altogether, we identified a new metabolic vulnerability in IDH1/2mut AMLs associated with a profound disturbance in lipid metabolism. Moreover, we show that treatment with metformin not only inhibits complex I but also induces cell death via ferroptosis in IDH2mut cells providing an alternative treatment option in combination with available IDH2mut targeted therapies for this subgroup of patients.

Trinickia violacea sp. nov. and Trinickia terrae sp. nov., isolated from forest soil.

Two Gram-stain negative, aerobic and rod-shaped bacterial strains, DHOD12T and 7GSK02T, were isolated from forest soil of Dinghushan Biosphere Reserve, Guangdong Province, PR China. Strain DHOD12T grew at 4-42 °C (optimum, 28-33 °C), pH 4.0-8.5 (optimum, pH 5.5-6.5) and in the presence of 0-1.5 % (w/v; optimum, 0-0.5 %)NaCl; while strain 7GSK02T grew at 12-42 °C (optimum, 28-33 °C), pH 4.0-8.5 (optimum, pH 5.0-6.0) and in the presence of 0-0.5 % (w/v; optimum, 0 %) NaCl. Strains DHOD12T and 7GSK02T had the highest 16S rRNA sequence similarities of 98.0 and 98.3 % with the same species Trinickia mobilis DHG64T, respectively, and 98.4 % between themselves. In the 16S rRNA phylogeny, they formed a clade that was sister to a major cluster consisting of all described Trinickia species. Phylogenomic analyses with the UBCG and PhyloPhlAn methods consistently showed that strains DHOD12T and 7GSK02T formed a clade with T. mobilis DHG64T that was a sister of a cluster containing the remainder of the Trinickia species. The DNA G+C contents of strains DHOD12T and 7GSK02T were 63.1 and 64.6 mol%, respectively. Digital DNA-DNA hybridization and average nucleotide identity values of strains DHOD12T, 7GSK02T and their closely related strains were in the ranges of 21.6-31.4 % and 77.1-86.9 %, respectively. These two strains had the same major respiratory quinone, ubiquinone-8, and both had C16 : 0, C17 : 0 cyclo and summed feature 8 (C18 : 1 ω7c/C18 : 1 ω6c) as their major fatty acids. Their major polar lipids were phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. Genomic analysis indicated that the two strains could have the potential to degrade aromatic compounds like other Trinickia species. On the basis of phenotypic and phylogenetic results, strains DHOD12T and 7GSK02T represent two novel species of the genus Trinickia, for which the names Trinickia violacea sp. nov. (type strain DHOD12T=LMG 30258T=CGMCC 1.15436T) and Trinickia terrae sp. nov. (type strain 7GSK02T=CGMCC 1.15432T=KCTC 62468T) are proposed.

Lacibacter sediminis sp. nov., isolated from contaminated freshwater sediment.

Two Gram-stain-negative bacterial strains, S13-6-6 and S13-6-22T, were isolated from sediment sample collected at a water depth of 4 m from Lake Hongze, Jiangsu Province, PR China. The cells of strains S13-6-6 and S13-6-22T were non-spore-forming, aerobic, non-motile and formed orange colonies on R2A agar. Comparative 16S rRNA gene sequence studies revealed a clear affiliation of the two strains with he phylum Bacteroidota, and revealed the highest pairwise sequence similarities with Lacibacter daechungensis H32-4T (97.8 %), Lacibacter cauensis NJ-8T (97.8 %), Lacibacter luteus TTM-7T (97.4 %) and Lacibacter nakdongensis SS2-56T (97.4 %). The results of phylogenetic analysis based on 16S rRNA gene sequences indicated that the strains formed a clear phylogenetic lineage with the genus Lacibacter. The major fatty acids were identified as iso-C15 : 1G, iso-C15 : 0, iso-C17 : 0 3-OH and summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) (>10 %), and the respiratory quinone was identified as menaquinone MK-7. The polar lipids consisted of phosphatidylethanolamine, two unidentified aminolipids, an unidentified phospholipid and six unidentified lipids. The genomic DNA G+C content was determined to be 40.2 mol% (HPLC) for strain S13-6-6 and 40.3 % (genome) for strain S13-6-22T. The combined genotypic and phenotypic data indicated that strains S13-6-6 and S13-6-22T represent a novel species of the genus Lacibacter, for which the name Lacibacter sediminis sp. nov. is proposed. The type strain is S13-6-22T (=CGMCC 1.17450T =JCM 35802T).

Nocardioides cremeus sp. nov., Nocardioides abyssi sp. nov. and Nocardioides oceani sp. nov., three actinobacteria isolated from Western Pacific Ocean sediment.

Three Gram-stain-positive, non-motile, short rod-shaped, catalase-positive and oxidase-negative actinomycete strains (SOB44T, SOB72T and SOB77T) were isolated from a deep-sea sediment sample collected from the Western Pacific Ocean. Cells of the three strains showed optimum growth at 30 °C and pH 7.0. Strains SOB44T, SOB72T and SOB77T could tolerate up to 10, 9 and 9 % (w/v) NaCl concentration and grow at pH 5.0-12.0, 5.0-11.0 and 5.0-11.0, respectively. Phylogenetic results based on 16S rRNA gene sequences showed that the three isolates belonged to the genus Nocardioides and were identified as representing three novel species based on 78.0-93.1 % average nucleotide identity and 21.3-50.0 % DNA-DNA hybridization values with closely related reference strains. Strains SOB44T, SOB72T and SOB77T showed highest 16S rRNA gene sequence similarity to Nocardioides salarius CL-Z59T (99.2 %), Nocardioides deserti SC8A-24T (99.2 %) and Nocardioides marmotae zg-579T (98.5 %), respectively. All three strains had MK-8(H4) as the respiratory quinone, iso-C16 : 0 as the major fatty acid, and phosphatidylglycerol, diphosphatidylglycerol and phosphatidylinositol as the major polar lipids. The diagnostic diamino acid in the cell-wall peptidoglycan of all three isolates was ll-diaminopimelic acid. The DNA G+C contents of strains SOB44T, SOB72T and SOB77T were 71.1, 72.9 and 72.9 mol%, respectively. Based on the phenotypic, phylogenetic and genotypic data, strains SOB44T, SOB72T and SOB77T clearly represent three novel taxa within the genus Nocardioides, for which the names Nocardioides cremeus sp. nov. (type strain SOB44T=JCM 35774T= MCCC M28400T), Nocardioides abyssi sp. nov. (type strain SOB72T=JCM 35775T=MCCC M28318T) and Nocardioides oceani sp. nov. (type strain SOB77T=JCM 35776T=MCCC M28544T) are proposed.