Achromobacter denitrificans SP1 produces pharmaceutically active 25C prodigiosin upon utilizing hazardous di(2-ethylhexyl)phthalate

Decylprodigiosin: a new member of the prodigiosin family isolated from a seaweed-associated Streptomyces

Bioprospecting actinobacterial secondary metabolism from untapped marine sources may lead to the discovery of biotechnologically-relevant compounds. While studying the diversity and bioactive potential of Actinomycetota associated with Codium tomentosum, a green seaweed collected in the northern Portuguese cost, strain CT-F61, identified as Streptomyces violaceoruber, was isolated. Its extracts displayed a strong anticancer activity on breast carcinoma T-47D and colorectal carcinoma HCT116 cells, being effective as well against a panel of human and fish pathogenic bacteria. Following a bioactivity-guided isolation pipeline, a new analogue of the red-pigmented family of the antibiotics prodigiosins, decylprodigiosin (1), was identified and chemically characterized. Despite this family of natural products being well-known for a long time, we report a new analogue and the first evidence for prodigiosins being produced by a seaweed-associated actinomycete.

Concerted regulation of OPG/RANKL/ NF‑κB/MMP-13 trajectories contribute to ameliorative capability of prodigiosin and/or low dose γ-radiation against adjuvant- induced arthritis in rats

BACKGROUND

Prodigiosin (PDG) is a microbial red dye with antioxidant and anti-inflammatory properties, although its effect on rheumatoid arthritis (RA) remains uncertain. Also, multiple doses of low dose γ- radiation (LDR) have been observed to be as a successful intervention for RA. Thus, the purpose of this study was to investigate the ameliorative potential of PDG and/or LDR on adjuvant-induced arthritis (AIA) in rats.

METHODS

The anti-inflammatory and anti-arthritic effects of PDG and/or LDR were examined in vitro and in vivo, respectively. In the AIA model, the arthritic indexes, paw swelling degrees, body weight gain, and histopathological assessment in AIA rats were assayed. The impact of PDG (200 µg/kg; p.o) and/or LDR (0.5 Gy) on the levels of pro- and anti-inflammatory cytokines (IL-1β, TNF-α, IL-6, IL-18, IL-17A, and IL-10) as well as the regulation of osteoprotegrin (OPG)/ receptor activator of nuclear factor κB ligand (RANKL)/ nuclear factor-κB (NF-κB)/MMP-13 pathways was determined. Methotrexate (MTX; 0.05 mg/kg; twice/week, i.p) was administered concurrently as a standard anti-arthritic drug.

RESULTS

PDG and/or LDR markedly diminished the arthritic indexes, paw edema, weigh loss in AIA rats, alleviated the pathological alterations in joints, reduced the levels of pro-inflammatory cytokines IL-1β, TNF-α, IL-6, IL-18, IL-17A, and RANKL in serum and synovial tissues, while increasing anti-inflammatory cytokines IL-10 and OPG levels. Moreover, PDG and/or LDR down-regulated the expression of RANKL, NF-κBp65, MMP13, caspase-3, and decreased the RANKL/OPG ratio, whereas OPG and collagen II were enhanced in synovial tissues.

CONCLUSION

PDG and/or LDR exhibited obvious anti-RA activity on AIA.

Quorum sensing mediated response of Achromobacter denitrificans SP1 towards prodigiosin production under phthalate stress

Quorum sensing is a density-dependent chemical process between bacteria, which may be intergenus or intragenus. N-acyl homoserine lactones (HSLs) are a type of small signaling molecules associated with Gram-negative bacteria for monitoring their own population density. The present study unveils the mechanism of HSLs in Achromobacter denitrificans SP1 while transforming di(2-ethylhexyl) phthalate (DEHP) into prodigiosin in a simple basal salt medium. The primary detection of HSLs was done by the colorimetric method. Fourier-transform infrared spectroscopy and liquid chromatography-mass spectrometry-quadrupole time-of-flight confirmed and identified the HSLs. The maximum production of HSLs was observed between 24 and 72 h of incubation, which is noted to be a peak time of DEHP degradation. A total of 57.2% of DEHP was degraded within 30 h and complete degradation was observed within 72 h of incubation. Regulation in the synthesis of various acyl-HSL molecules, viz. 3OC6-HSL in the initial stage of DEHP stress, 3OC8-HSL, and C10-HSL during the time of degradation and 3OC12-HSL on completion of degradation was noticed. The role of HSLs on the production of prodigiosin was confirmed using vanillin as an HSL inhibitor. Through the selective activation of HSL molecules, A. denitrificans SP1 sustain the changing stressful conditions. Supplementation of acyl-HSL signal molecules may boost up the efficacy of A. denitrificans SP1 in both DEHP degradation and prodigiosin production which offers great potential towards the management of DEHP containing plastic wastes.

Enhanced biodegradation of an endocrine disrupting micro-pollutant: Di (2-ethylhexyl) phthalate using biogenic self-assembled monolayer of silver nanoparticles

Di (2-ethylhexyl) phthalate (DEHP) is one of the predominant plasticizer and an endocrine disrupting chemical occurring almost in all partitions of the environment. Though DEHP occur at lower concentration, reluctance arises due to their ability to disrupt endocrine system even lower concentration. In the present study, DEHP was assessed for degradation at minimal level (1-100 μg L^-1) by a novel bacterial strain, Rhodococcus jostii PEVJ9. In the experimental design, significant variables were concentration of silver nitrate and DEHP, pH, temperature, time and agitation. Degradation without SAM-silver nanoparticles was 30-66% (predicted value = 30.8-66.8%, R² = 99.7%) while, degradation in the presence of SAM-silver nanoparticles onto bacterial cells was 100% (predicted value = 98.4-102.1%, R² = 99.6%) within 72 h. In short, this is the first report illustrating the experimental designs in biogenic synthesis of SAM-silver nanoparticles and enhanced degradation of DEHP at minimal level. The study overcomes poor bioavailability and assimilation of DEHP at lower concentration by the microbial population present in the environment. Thus, an efficient clean-up would prevent or minimize DEHP exposure at all trophic levels ranging from feminization of fishes to reproductive disorders in humans.

Prodigiosins from a marine sponge-associated actinomycete attenuate HCl/ethanol-induced gastric lesion via antioxidant and anti-inflammatory mechanisms

Gastric ulcer is sores that form in the stomach mucosal layer because of erosion caused by high acid secretion and excessive use of non-steroidal anti-inflammatory drugs. Prodigiosins (PdGs) are red-pigmented secondary metabolites produced by bacteria, including actinomycetes. Butylcycloheptylprodigiosin (1) and undecylprodigiosin (2) were identified and isolated from a crude extract of the actinomycete RA2 isolated from the Red Sea Sponge Spheciospongia mastoidea. Chemical structure of 1 and 2 was determined by NMR and mass spectroscopy. Although their antioxidant and anti-inflammatory properties are known, their effect on gastric lesion is unknown. Therefore, this study aimed to investigate gastroprotective effects of PdGs against HCl/ethanol-induced gastric lesion in rats. Oral pretreatment with PdGs (100, 200, and 300 mg/kg) attenuated severity of HCl/ethanol-induced gastric mucosal injury, as evidenced by decreases in gastric lesion index scores, ulceration area, histopathologic abnormality, and neutrophil infiltration. These effects were comparable to those of omeprazole, a standard anti-gastric ulcer agent. HCl/ethanol-induced gastric erosions was associated with tremendous increases in lipid peroxidation, nitric oxide, and pro-inflammatory cytokines and mediators (myeloperoxidase, interleukin-1β, tumor necrosis factor-α, and cyclooxygenase-2), and with significant decreases in enzymatic and non-enzymatic antioxidant activities. However, PdGs ameliorated gastric inflammation and oxidative stress by downregulating nuclear factor kappa B and inducible nitric oxide synthase expression and upregulating heme oxygenase-1 expression. PdGs prevented gastric mucosal apoptosis by downregulating Bax and caspase-3 expression and upregulating Bcl-2 expression, thereby increasing prostaglandin E2 production. Our results suggested that PdGs exerted gastroprotective effects by decreasing the levels of inflammatory mediators, apoptotic markers, and antioxidants.

Achromobacter denitrificans SP1 efficiently utilizes 16 phthalate diesters and their downstream products through protocatechuate 3,4-cleavage pathway

This study provides physical and analytical evidences for the efficient utilization of most of the commercially available phthalate diesters by Achromobacter denitrificans SP1, coupled with the demonstration of a plausible degradation pathway. We tested 17 phthalate diesters [viz., ditridecyl phthalate, diisodecyl phthalate (DIDP), di(2-ethylhexyl)phthalate (DEHP), di-n-octyl phthalate (DOP), bis(2-ethylhexyl)isophthalate (BEIP), dihexyl phthalate (DHP), dibutyl phthalate (DBP), dicyclohexyl phthalate (DCHP), diphenyl phthalate (DPP), benzyl butyl phthalate (BBP), diamyl phthalate (DAmP), diisobutyl phthalate, dipropyl phthalate, dially phthalate (DAlP), diethyl phthalate, diethyl terephthalate and dimethyl phthalate (DMP)], and their major degradation products for the degradation efficiency of A. denitrificans SP1 in Wx medium. It efficiently utilized 16 phthalate diesters (except DAlP), and showed general preference toward phthalate diesters with longer side chains (utilized ~10mM in 48h) than those with shorter side chains and with cyclic structures (utilized ~5mM in 48h) accompanied by a sharp decline of pH to ~5 from initial 7. In a detailed study, about 37mM (~15g/L) DEHP was utilized in 48h. Moreover, A. denitrificans SP1 produced reddish-pink pigment when DIDP, DEHP, DOP, DHP, DBP, DIBP, BBP, DAmP, DCHP, DPP or DMP was supplied in the medium. From the available evidences, it seems that its putative phthalate diester degradation pathway contains the following check points: phthalate diesters, phthalate monoesters, phthalate (4,5-dioxygenase), protocatechuate (3,4-dioxygenase), and TCA cycle. Nonspecificity toward utilization of phthalate diesters, especially with greater specificity to phthalate diesters having longer side chain, and the characteristic sticky reddish-pink (or colorless) cell clump formation in the presence of phthalate diesters makes A. denitrificans SP1 a very attractive candidate to be employed as an efficient biofactory in waste water treatment processes.

Removal of nitrogen by heterotrophic nitrification-aerobic denitrification of a novel metal resistant bacterium Cupriavidus sp. S1

A novel heterotrophic nitrifying and metal resistant bacterium was isolated and identified as Cupriavidus sp. S1. The utilization of ammonium, nitrate and nitrite as well as the production of N2 proved the heterotrophic nitrification and aerobic denitrification ability of S1. The ammonium, nitrate and nitrite removal efficiencies were 99.68%, 98.03% and 99.81%, with removal rates of 10.43, 8.64 and 8.36mg/L/h, respectively. A multiple regression equation well described the relationship between carbon source utilization, cell growth and nitrification. Keeping the shaking speed at 120rpm was beneficial for denitrification. Moreover, different forms of nitrogen source could be utilize in simultaneous nitrification and denitrification. Additionally, the efficient removal of ammonium occurred at 20.0mg/LZn(2+), or 10.0mg/LNi(2+) or 8.0mg/LCu(2+) or 5.0mg/LCr(6+), 33.35mmol/L sodium pyruvate, C/N 12-28. These findings demonstrate that S1 was effective for nitrogen removal in industrial wastewater containing heavy metal.

A monograph on the remediation of hazardous phthalates

Phthalates or phthalic acid esters are a group of xenobiotic and hazardous compounds blended in plastics to enhance their plasticity and versatility. Enormous quantities of phthalates are produced globally for the production of plastic goods, whose disposal and leaching out into the surroundings cause serious concerns to the environment, biota and human health. Though in silico computational, in vitro mechanistic, pre-clinical animal and clinical human studies showed endocrine disruption, hepatotoxic, teratogenic and carcinogenic properties, usage of phthalates continues due to their cuteness, attractive chemical properties, low production cost and lack of suitable alternatives. Studies revealed that microbes isolated from phthalate-contaminated environmental niches efficiently bioremediate various phthalates. Based upon this background, this review addresses the enumeration of major phthalates used in industry, routes of environmental contamination, evidences for health hazards, routes for in situ and ex situ microbial degradation, bacterial pathways involved in the degradation, major enzymes involved in the degradation process, half-lives of phthalates in environments, etc. Briefly, this handy module would enable the readers, environmentalists and policy makers to understand the impact of phthalates on the environment and the biota, coupled with the concerted microbial efforts to alleviate the burden of ever increasing load posed by phthalates.

Achromobacter denitrificans strain SP1 efficiently remediates di(2-ethylhexyl)phthalate

This study describes how Achromobacter denitrificans strain SP1, a novel isolate from heavily plastics-contaminated sewage sludge efficiently consumed the hazardous plasticizer, di(2-ethylhexyl)phthalate (DEHP) as carbon source supplemented in a simple basal salt medium (BSM). Response surface methodology was employed for the statistical optimization of the process parameters such as temperature (32°C), agitation (200 rpm), DEHP concentration (10 mM), time (72 h) and pH (8.0). At these optimized conditions, experimentally observed DEHP degradation was 63%, while the predicted value was 59.2%; and the correlation coefficient between them was 0.998, i.e., highly significant and fit to the predicted model. Employing GC-MS analysis, the degradation pathway was partially deduced with intermediates such as mono(2-ethylhexyl)phthalate and 2-ethyl hexanol. Briefly, this first report describes A. denitrificans strain SP1 as a highly efficient bacterium for completely remediating the hazardous DEHP (10 mM) in 96 h in BSM (50% consumed in 60 h), which offers great potentials for efficiently cleaning the DEHP-contaminated environments such as soil, sediments and water upon its deployment.