Exploring the prognostic value and potential therapeutic strategies of MS4A6A in glioblastoma: A comprehensive analysis of single-cell and multi-omics data.

Glioblastoma (GBM) is a highly aggressive and treatment-resistant malignancy that poses a significant challenge in modern medicine. Despite advances in surgical resection, radiotherapy and chemotherapy, complete eradication of GBM remains elusive due to its diffuse invasion into the brain parenchyma and propensity for recurrence. The tumour microenvironment (TME), particularly macrophages, has emerged as a critical player in GBM progression, invasion and metastasis. In the immune microenvironment of glioma, MS4A6A exhibits unique expression characteristics in macrophages. This study aimed to investigate the potential role of MS4A6A, a gene associated with aging and neurodegenerative diseases, in GBM and its potential as a prognostic biomarker and therapeutic target.

Improved Standard Addition Method for Measuring Stable Isotopic Compositions and Its Application to Sulfur Isotope Composition.

The standard addition method (SAM) is widely used to measure the isotopic compositions of natural samples, particularly those with a complex matrix. However, traditional SAM has limitations for isotope systems with significant variations in isotope composition due to its reliance on approximation in calculation and the requirement for a priori estimates of analyte isotopic compositions and accurate concentrations. To overcome the issues, our work proposes an improved SAM that explicitly calculates isotope ratio R (i.e., XE/YE, 34S/32S for example) instead of approximating R* (mass number of isotope X divided by total mass number of all isotopes of an element) with R in SAM. Additionally, the sample fraction within standard-sample mixture in improved SAM is determined using the isotope compositions of standards, sample-standard mixtures, and the mixtures of both standards, rather than relying on sample concentrations and volumes. Both improvements not only overcome the shortcomings of traditional SAM but also empowered the approach's ability to accurately determine sample concentrations. To validate its effectiveness, we applied the improved SAM to natural samples with substantial sulfur (S) isotope variation (1.94 to 27.19‰) and low S concentration (0.81 to 3.47 µg g-1). The calculated δ34S values and concentrations of these samples are consistent with direct measurements within the error ranges while reducing sample sizes to 20% of those required for direct measurement. Moreover, our method achieves higher accuracy in δ34S values compared with traditional SAM. Both comparisons affirm the reliability and superiority of improved SAM.

Design, synthesis and structure-activity relationship of 1,8-naphthalimide derivatives as highly potent hCYP1B1 inhibitors.

Human cytochrome P450 1B1 enzyme (hCYP1B1), a member of hCYP1 subfamily, plays a crucial role in multiple diseases by participating in many metabolic pathways. Although a suite of potent hCYP1B1 inhibitors have been previously reported, most of them also act as aryl hydrocarbon receptor (AhR) agonists that can up-regulate the expression of hCYP1B1 and then counteract their inhibitory potential in living systems. This study aimed to develop novel efficacious hCYP1B1 inhibitors that worked well in living cells but without AhR agonist effects. For these purposes, a series of 1,8-naphthalimide derivatives were designed and synthesized, and their structure-activity relationships (SAR) as hCYP1B1 inhibitors were analyzed. Following three rounds SAR studies, several potent hCYP1B1 inhibitors were discovered, among which compound 3n was selected for further investigations owing to its extremely potent anti-hCYP1B1 activity (IC50 = 0.040 nM) and its blocking AhR transcription activity in living cells. Inhibition kinetic analyses showed that 3n potently inhibited hCYP1B1 via a mix inhibition manner, showing a Ki value of 21.71 pM. Docking simulations suggested that introducing a pyrimidine moiety to the hit compound (1d) facilitated 3n to form two strong interactions with hCYP1B1/heme, viz., the C-Br⋯π halogen bond and the N-Fe coordination bond. Further investigations demonstrated that 3n (5 µM) could significantly reverse the paclitaxel (PTX) resistance in H460/PTX cells, evidenced by the dramatically reduced IC50 values, from 632.6 nM (PTX alone) to 100.8 nM (PTX plus 3n). Collectively, this study devised a highly potent hCYP1B1 inhibitor (3n) without AhR agonist effect, which offered a promising drug candidate for overcoming hCYP1B1-associated drug resistance.

Design, synthesis, and biological evaluation of novel 1-amido-2-one-4-thio-deoxypyranose as potential antitumor agents for multiple myeloma.

This study reported the design and synthesis of novel 1-amido-2-one-4-thio-deoxypyranose as inhibitors of potential drug target TRIP13 for developing new mechanism-based therapeutic agents in the treatment of multiple myeloma (MM). In comparison with the positive control DCZ0415, the most active compounds C16, C18, C20 and C32 exhibited strong anti-proliferative activity against human MM cell lines (ARP-1 and NCI-H929) with IC50 values of 1 âˆ¼ 2 µM. While the surface plasmon resonance (SPR) and ATPase activity assays demonstrated that the representative compound C20 is a potent inhibitor of TRIP13, C20 also showed good antitumor activity in vivo on BALB/c nude mice xenografted with MM tumor cells. An initial structure-activity study showed that the carbonyl group is crucial for anticancer activity. Overall, this study provided novel 1-amido-2-one-4-thio-deoxypyranoses, which are entirely different from previously reported potent inhibitor structures of TRIP13, and thus would aid the development of carbohydrate-based novel agents in MM pharmacotherapy.

Knockdown of lncRNA AU020206 could inhibit microglia apoptosis in ischemic stroke.

The diagnostic biomarkers associated with ischemic stroke (IS) that may have clinical utility remain elucidated. Thus, the potential functional lncRNAs in IS were explored. The Gene Expression Omnibus database provided the transcriptome profile of IS for download. WGCNA analysis and integrated bioinformatics were used to find genes that were differentially expressed (DEGs). The Starbase database created the lncRNA-based ceRNA network. In order to investigate the molecular mechanism and involved pathways of DEGs in IS, functional enrichment analysis was carried out. Using qRT-PCR, lncRNAs identified as putative IS biomarkers were confirmed to be expressed in a permanent middle cerebral artery occlusion (MCAO) model. Using the annexin V/PI apoptosis test, the amount of apoptosis in oxygen-glucose deprivation (OGD) cells was measured. A total of 1600 common differentially expressed - protein-coding RNA (DE-pcRNAs) and 26 DE-lncRNAs were identified. The results of enrichment analysis indicate that the cytokine may be regulated by common DE-pcRNAs and are vital in the progress of IS. A lncRNAs-mediated ceRNA network including lncRNAs AU020206, Brip1os, F630028O10Rik and 9530082P21Rik was constructed. The expression of these lncRNAs was significantly increased in MCAO model. Knockdown of lncRNA AU020206 inhibited microglia apoptosis in OGD cell model. We constructed a lncRNAs-mediated ceRNA network and found that lncRNA AU020206 inhibited microglia apoptosis in OGD cell model. These findings provided further evidence for the diagnosis and a novel avenue for targeted therapy of IS.

Double Spike-Standard Addition Technique and Its Application in Measuring Isotopes.

Double spike (DS) method has been extensively used in determining stable isotope ratios of many elements. However, challenges remain in obtaining high-precision isotope data for ultra-trace elements owing to the limitations of instrumental signal-to-noise ratios and the systematics of precision of DS-based measurements. Here, the DS-standard addition (SA) (DSSA) technique is proposed to improve measurements of isotope compositions of ultra-trace elements in natural samples. According to the U-shaped relationship between DS measurement uncertainty and the spike/sample ratio, theoretical equations and an error propagation model (EPM) were constructed comprehensively. In our method, a spiked secondary standard solution with a high, precisely known spike/sample ratio is mixed with samples such that the mixtures have spike/sample ratios within the optimal range. The abundances of the samples relative to the added standards (sample fraction; fspl) and the samples' isotope ratios can then be obtained exactly using a standard DS data reduction routine and the isotope binary mixing model. The accuracy and precision of the DSSA approach were verified by measurements of cadmium and molybdenum isotopes at as low as 5 ng levels. Compared with traditional DS measurements, the sample size for isotope analysis is reduced to 1/6-1/5 of the original with no loss of measurement precision. The optimal mixing range fspl = 0.15-0.5 is recommended. The DSSA method can be extended to isotope measurement of more than 33 elements where the DS method is applicable, especially for the ultra-trace elements such as platinum group and rare earth element isotopes.

Dynamic patterns of quorum sensing signals in phycospheric microbes during a marine algal bloom.

In the marine environment, the interactions among various species based on chemical signals play critical roles in influencing microbial structure and function. Quorum sensing (QS), the well-known signal-dependent communication autoinducer, is an important regulator in complex microbial communities. Here, we explored the QS gene profiles of phycosphere bacteria during a microcosmic phytoplankton bloom using metagenomic sequence data. More than fifteen subtypes of QS systems and 211,980 non-redundant amino acid sequences were collected and classified for constructing a hierarchical quorum-sensing database. The abundance of the various QS subtypes varied at different bloom stages and showed a strong correlation with phycosphere microorganisms. This suggested that QS is involved in regulating the phycosphere microbial succession during an algal bloom. A neutral community model revealed that the QS functional gene community assemblies were driven by stochastic processes. Co-occurrence model analysis showed that the QS gene networks of phycospheric microbes had similar topological structure and functional composition, which is a potential cornerstone for maintaining signal communication and population stabilization among microorganisms. Overall, QS systems have a strong relationship with the development of algal blooms and participate in regulating algal-associated microbial communities as chemical signals. This research reveals the chemical and ecological behavior of algal symbiotic bacteria and expands the current understanding of microbial dynamics in marine algal blooms.

Antibiotic Resistance Determinants and Virulence Factors of Hypervirulent and Carbapenem Non-Susceptible Pseudomonas aeruginosa.

BACKGROUND: The aim was to investigate the distribution of antibiotic resistance determinants and virulence factors in a group of carbapenem non-susceptible Pseudomonas aeruginosa (P. aeruginosa). METHODS: From March 2018 to May 2019, a total of 98 P. aeruginosa samples were collected from 6 hospitals in Ningbo and Hangzhou, Zhejiang Province, China. Drug susceptibility tests to 13 antimicrobial agents were conducted. The presence of antibiotic resistance determinants and virulence factors were investigated by PCR, including 39 ß-lactamase genes, 14 aminoglycoside modifying enzyme genes, 10 16SrRNA methylase genes, and 11 virulence genes. Phylogenetics of 98 P. aeruginosa was analyzed by sample cluster analysis (UPGMA). RESULTS: PCR revealed the presence of 7 ß-lactamase genes, 5 aminoglycoside modifying enzymes, 1 16S rRNA methylase gene, and 8 virulence genes in total, at least 2 ß-lactamase genes and 4 virulence genes were positive in every isolate. In addition, regional differences in distributions of resistance and virulence genes remained between 2 cities. Sample cluster analysis showed that the strains had obvious aggregation and were divided into several clusters, strains in the same cluster were isolated from different hospitals, even from different cities. CONCLUSIONS: Carrying resistance genes blaPDC and blaOXA-50 group and virulence genes plcH, aprA, and algD were the important epidemiological characteristics of this group of P. aeruginosa. The present findings provide insights into the mechanisms of hypervirulence as well as resistance to ß-lactams and aminoglycosides. To the best of our knowledge, this is the first report of blaPDC, blaOXA-50, and aph(3')-XV in P. aeruginosa in China.

Adsorption of cadmium on clay-organic associations in different pH solutions: The effect of amphoteric organic matter.

Clay minerals are important soil components and usually coexist with organic matter, forming mineral-organic associations (MOAs), which control the speciation, mobility, and bioavailability of heavy metals. However, the adsorption mechanism of cadmium (Cd) by MOAs is still unclear, especially for the associations of amphotericorganic matter and clay minerals. In this study, 12-aminododecanoic acid (ALA) and montmorillonite (Mt) were chosen to prepare MOAs via intercalation (Mt-ALA composite) and physical mixing (Mt-ALA mixture). Batch experiments were conducted to investigate the adsorption mechanism of Cd(II) by MOAs under different pH values and initial Cd(II) concentrations. The results showed that the Cd(II) adsorption capacities followed as Mt > Mt-ALA mixture > Mt-ALA composite under acidic conditions, Mt-ALA mixture > Mt > Mt-ALA composite under neutral conditions, and Mt-ALA mixture > Mt-ALA composite > Mt under alkaline conditions, suggesting the adsorption behaviors of Cd(II) by MOAs were primarily constrained by the speciation of ALA and solution pH. Under acidic conditions, cationic HALA+ could intercalate into the interlayer of Mt and occupy the adsorption sites, reducing the adsorption capacity of Cd(II). As pH increased to neutral, HALA+ decreased and changed to a zwitterionic state, which caused ALA to release out from the interlayer of Mt-ALA composite or not easily enter into Mt-ALA mixture and promoted Cd(II) adsorption. Under alkaline conditions, the increase of anion ALA- would cause ALA to be mainly adsorbed on the surface of Mt and chelate with Cd(II), enhancing the adsorption of Cd(II). Further analysis by Fourier transform infrared and X-ray photoelectron spectroscopy indicated that the carboxyl and amino groups of ALA both participated in the adsorption of Cd(II). These findings could extend the knowledge on the mobility and fate of Cd in clay-based soils and be used as a basis for understanding the biogeochemical behavior of Cd in the environment.

Noninvasive Blood Glucose Concentration Measurement Based on Conservation of Energy Metabolism and Machine Learning.

Blood glucose (BG) concentration monitoring is essential for controlling complications arising from diabetes, as well as digital management of the disease. At present, finger-prick glucometers are widely used to measure BG concentrations. In consideration of the challenges of invasive BG concentration measurements involving pain, risk of infection, expense, and inconvenience, we propose a noninvasive BG concentration detection method based on the conservation of energy metabolism. In this study, a multisensor integrated detection probe was designed and manufactured by 3D-printing technology to be worn on the wrist. Two machine-learning algorithms were also applied to establish the regression model for predicting BG concentrations. The results showed that the back-propagation neural network model produced better performance than the multivariate polynomial regression model, with a mean absolute relative difference and correlation coefficient of 5.453% and 0.936, respectively. Here, about 98.413% of the predicted values were within zone A of the Clarke error grid. The above results proved the potential of our method and device for noninvasive glucose concentration detection from the human wrist.

Arsenic and Cadmium in Soils from a Typical Mining City in Huainan, China: Spatial Distribution, Ecological Risk Assessment and Health Risk Assessment.

In order to determine the ecological risk and health risk of Arsenic (As) and Cadmium (Cd) in soils from a typical mining city in Huainan, a total of 99 soil samples were collected and analyzed. The results showed that the concentrations of As and Cd ranged from 3.2 to 39.50 and 0.01 to 0.19 mg/kg, respectively, which exceeded the soil background values by 6.06 and 14.14%, respectively. The soil pH and content of organic carbon demonstrated no significant (P > 0.05) correlation with the As and Cd concentrations, while the land use types significantly (P < 0.05) affected the As and Cd distribution. According to the Nemero synthesis pollution index, three spot areas were identified as moderately to strongly polluted. The potential ecological risk index ranged from 4.34 to 108.64, which represented that the potential ecological risk was low. In addition, children faced more carcinogenic risk of As. Consequently, mining has increased the concentrations of As and Cd in soils, and the carcinogenic risk of As to children should be paid more attention.

Microscale Investigation into Selenium Distribution and Speciation in Se-Rich Soils from Enshi, China.

In this study, we investigated the distribution and chemical speciation of Se in Se-rich soil by using micro-focused X-ray absorption near-edge structure (µ-XANES) spectroscopy coupling with X-ray fluorescence (µ-XRF) mapping. The microscale distribution showed that Se is heterogeneously distributed in the soil from seleniferous areas in Enshi, China. Se K-edge µ-XANES analysis suggested that Se is mainly present as Se(IV), organic Se(-II) or Se(0) species in Se-rich agricultural soil. The findings from this study would help improve the understanding of the fate, mobility, bioavailability, and biogeochemical cycling of Se in the seleniferous soil environment.

Thermus thermophilus DNA Ligase Connects Two Fragments Having Exceptionally Short Complementary Termini at High Temperatures.

Thermus thermophilus DNA ligase (Tth DNA ligase) is widely employed for cloning, enzymatic synthesis, and molecular diagnostics at high temperatures (e.g., 65 °C). It has been long believed that the complementary ends must be very long (e.g., >30 bp) to place two DNA fragments nearby for the ligation. In the current study, the length of the complementary portion was systematically varied, and the ligation efficiency was evaluated using the high resolution melting (HRM) method. Unexpectedly, very short oligonucleotides (7-10 nt) were successfully ligated on the complementary overhang attached to a dsDNA at 70 °C. Furthermore, sticky ends with the overhang of only 4 nt long, available after scission with many restriction enzymes, were also efficiently ligated at 45-70 °C. The ligation yield for the 6-nt-long sticky ends was as high as 80%. It was concluded that Tth DNA ligase can be used as a unique tool for DNA manipulation that cannot be otherwise easily accomplished.

Opportunistic bacteria use quorum sensing to disturb coral symbiotic communities and mediate the occurrence of coral bleaching.

Coral associated microorganisms, especially some opportunistic pathogens can utilize quorum-sensing (QS) signals to affect population structure and host health. However, direct evidence about the link between coral bleaching and dysbiotic microbiomes under QS regulation was lacking. Here, using 11 opportunistic bacteria and their QS products (AHLs, acyl-homoserine-lactones), we exposed Pocillopora damicornis to three different treatments: test groups (A and B: mixture of AHLs-producing bacteria and cocktail of AHLs signals respectively); control groups (C and D: group A and B with furanone added respectively); and a blank control (group E: only seawater) for 21 days. The results showed that remarkable bleaching phenomenon was observed in groups A and B. The operational taxonomic units-sequencing analysis shown that the bacterial network interactions and communities composition were significantly changed, becoming especially enhanced in the relative abundances of Vibrio, Edwardsiella, Enterobacter, Pseudomonas, and Aeromonas. Interestingly, the control groups (C and D) were found to have a limited influence upon host microbial composition and reduced bleaching susceptibility of P. damicornis. These results indicate bleaching's initiation and progression may be caused by opportunistic bacteria of resident microbes in a process under regulation by AHLs. These findings add a new dimension to our understanding of the complexity of bleaching mechanisms from a chemoecological perspective.

High-Sensitivity Measurement of Cr Isotopes by Double Spike MC-ICP-MS at the 10 ng Level.

High-sensitivity and high-precision (2 SD ≤ 0.06‰) measurement of chromium (Cr) isotopes at the 10 ng level was successfully carried out using double spike multiple-collector inductively couple plasma mass spectrometry (MC-ICP-MS). To enhance the signal sensitivity and stability, the Aridus II desolvating nebulizer system was improved by placing its waste gas trap bottle in an ice chamber (5 °C cold trap). This setup, beyond Cr isotope analysis, can be applied to most heavy metal isotope measurements. The sensitivity of the 52Cr signal is ≥300 V mg-1 L (with a 1011Ω amplifier and a 110 µL min-1 uptake rate), an enhancement of ≥1.5 times compared to the Aridus II without the cold trap. In addition, the relative standard deviation of the 52Cr signal varied ≤4% over 8 h, demonstrating high stability. The δ53Cr values of common geological reference materials determined using 10 ng of Cr are in excellent agreement with results measured at 25 ng and 50 ng and are consistent with previous determinations, validating the accurate and precise Cr isotope ratio measurements. An empirical method is proposed to correct for the residual (after subtraction) effect of Fe interference on δ53Cr determination. This method relies on a linear relationship between the [Fe]/[Cr] and δ53Cr shift within one analytical session. Finally, we report the δ53Cr values of 19 new reference materials, ranging from -0.44‰ to 0.49‰. Among them, GSS-7 (-0.44 ± 0.02‰, 2 SD, n = 5), GSS-4 (0.48 ± 0.02‰, 2 SD, n = 5), and GSD-10 (0.49 ± 0.05‰, 2 SD, n = 5) can be used as candidate reference materials for interlaboratory comparisons to complement existing ones that are mostly isotopically unfractionated from the bulk silicate earth.

Effective Characterization of DNA Ligation Kinetics by High-Resolution Melting Analysis.

High-resolution melting (HRM) analysis has been improved and applied for the first time to quantitative analysis of enzymatic reactions. By using the relative ratios of peak intensities of substrates and products, the quantitativity of conventional HRM analysis has been improved to allow detailed kinetic analysis. As an example, the ligation of sticky ends through the action of T4 DNA ligase has been kinetically analyzed, with comprehensive data on substrate specificity and other properties having been obtained. For the first time, the kinetic parameters (kobs and apparent Km ) of sticky-end ligation were obtained for both fully matched and mismatched sticky ends. The effect of ATP concentration on sticky-end ligation was also investigated. The improved HRM method should also be applicable to versatile DNA-transforming enzymes, because the only requirement is that the products have Tm values different enough from the substrates.

A FRET-based ratiometric fluorescent probe to detect cysteine metabolism in mitochondria.

As an important biothiol in living cells, cysteine is closely related to oxidative damage in living organisms. Sulfite from cysteine metabolism in living cells plays a crucial role in maintaining homeostasis in an organism, and the unbalance of sulfite in vivo would lead to multiple diseases. Thus the development of a new fluorescent probe for cysteine metabolism is needed urgently in mitochondria which are the main place of cysteine metabolism. Herein we construct a novel targeting mitochondria fluorescent probe CP-K based on the FRET mechanism to visualize sulfite in living MCF-7 cells. Probe CP-K displays a large Stokes shift of 150 nm, a low detection limit (26.3 nM) and "naked eye" detection after the addition of HSO3-. Importantly, it is appropriate for imaging the endogenous sulfite from cysteine metabolism in living cells.

Tropicibacter alexandrii sp. nov., a novel marine bacterium isolated from the phycosphere of a dinoflagellate, Alexandrium minutum.

An aerobic, Gram-negative, rod-shaped, non-motile bacterium was isolated from a liquid culture of the dinoflagellate Alexandrium minutum and designated as strain LMIT003T. Analyses of 16S rRNA gene sequences revealed that this strain is affiliated with the genus Tropicibacter in the family Rhodobacteraceae of the class Alphaproteobacteria and shows high similarity (97.3%) with the type species Tropicibacter naphthalenivorans C02T. Phylogenetic analysis based on core genes showed that the isolate groups with members of the genus Tropicibacter. The G + C content of strain LMIT003T was determined to be 61.9 mol%. The major fatty acids identified included summed feature 8 (C18:1 ω7c/C18:1 ω6c), C18:0, C12:1 3-OH and C16:0. The sole respiratory lipoquinone was found to be ubiquinone-10. The major polar lipids were found to be phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, two unidentified aminolipids and four unidentified phospholipids. The draft genome size of strain LMIT003T was determined to be 4.8 Mbp. The average nucleotide identity values between strain LMIT003T and reference Tropicibacter species were determined to be 78.7% (T. naphthalenivorans) and 74.2% (Tropicibacter phthalicicus). Based on physiological, chemotaxonomic and phylogenetic analysis, strain LMIT003T is concluded to represent a novel species in the genus Tropicibacter, for which the name Tropicibacter alexandrii sp. nov., is proposed. The type strain is LMIT003T (= CICC 24660T = KCTC 62895T).

The Rhodamine Isothiocyanate Analogue as a Quorum Sensing Inhibitor Has the Potential to Control Microbially-Induced Biofouling.

Quorum sensing inhibitors (QSIs) have been proven to be an innovative approach to interfering with biofilm formation, since this process is regulated by QS signals. However, most studies have focused on single-species biofilm formation, whereas studies of the effects of signal interference on the development of multispecies biofilm, especially in the natural environment, are still lacking. Here we develop and evaluate the anti-biofilm capability of a new QSI (rhodamine isothiocyanate analogue, RIA) in natural seawater. During the experiment, biofilm characteristics, microbial communities/functions and network interactions were monitored at 36, 80, and 180 h, respectively. The results showed that the biomass and 3D structure of the biofilm were significantly different in the presence of the QSI. The expression of genes involved in extracellular polysaccharide synthesis was also downregulated in the QSI-treated group. Dramatic differences in microbial composition, ß-diversity and functions between the RIA-treated group and the control group were also observed, especially in the early stage of biofilm development. Furthermore, co-occurrence model analysis showed that RIA reduced the complexity of the microbial network. This study demonstrates that rhodamine isothiocyanate analogue is an efficient QS inhibitor and has potential applications in controlling biofouling caused by multispecies biofilm, especially in the early stage of biofouling formation.

Azo dye degrading bacteria tolerant to extreme conditions inhabit nearshore ecosystems: Optimization and degradation pathways.

Nearshore ecosystems are transitional zones, and they may harbor a diverse microbial community capable of degrading azo dyes under extreme environmental conditions. In this study, thirteen bacterial strains capable of degrading eight azo dyes were isolated in nearshore environments and characterized using high throughput 16 S rRNA sequencing. The results of this study demonstrate that the biodegradability of azo dyes was influenced by their chemical structure and position of functional groups as well as the type of bacteria. The decolorization rate of Methyl Orange (95%) was double that of the heavier and sterically hindered Reactive Yellow 84 (<40%). Shewanella indica strain ST2, Oceanimonas smirnovii strain ST3, Enterococcus faecalis strain ST5, and Clostridium bufermentans strain ST12 demonstrated potential application in industrial effluent treatment as they were tolerant to a wide range of environmental parameters (pH: 5-9, NaCl: 0-70 g L-1, azo dye concentration: 100-2000 mg L-1) including exposure to metals. Analysis of the transformation products using GC-MS revealed that different bacterial strains may have different biotransformation pathways. This study provides critical insight on the in-situ biotransformation potential of azo dyes in marine environments.