The production and bioactivity of prodigiosin: quo vadis?

Enzyme-responsive mannose-grafted magnetic nanoparticles for breast and liver cancer therapy and tumor-associated macrophage immunomodulation

BACKGROUND

Chemo-immunotherapy modifies the tumor microenvironment to enhance the immune response and improve chemotherapy. This study introduces a dual-armed chemo-immunotherapy strategy combating breast tumor progression while re-polarizing Tumor-Associated Macrophage (TAM) using prodigiosin-loaded mannan-coated magnetic nanoparticles (PG@M-MNPs).

METHODS

The physicochemical properties of one-step synthetized M-MNPs were analyzed, including X-ray diffraction, FTIR, DLS, VSM, TEM, zeta potential analysis, and drug loading content were carried out. Biocompatibility, cancer specificity, cellular uptake, and distribution of PG@M-MNPs were investigated using fluorescence and confocal laser scanning microscopy, and flow cytometry. Furthermore, the expression levels of IL-6 and ARG-1 after treatment with PG and PG@M-MNPs on M1 and M2 macrophage subsets were studied.

RESULTS

The M-MNPs were successfully synthesized and characterized, demonstrating a size below 100 nm. The release kinetics of PG from M-MNPs showed sustained and controlled patterns, with enzyme-triggered release. Cytotoxicity assessments revealed an enhanced selectivity of PG@M-MNPs against cancer cells and minimal effects on normal cells. Additionally, immuno-modulatory activity demonstrates the potential of PG@M-MNPs to change the polarization dynamics of macrophages.

CONCLUSION

These findings highlight the potential of a targeted approach to breast cancer treatment, offering new avenues for improved therapeutic outcomes and patient survival.

Induction of Endoplasmic Reticulum Stress by Prodigiosin in Yeast Saccharomyces cerevisiae

Prodigiosin, a red pigment produced by numerous bacterial species, exerts various antibiotic effects on prokaryotic and eukaryotic organisms. For instance, human carcinoma cell lines appear to suffer from endoplasmic reticulum (ER) stress in the presence of prodigiosin. Here, we demonstrated that prodigiosin also triggers the unfolded-protein response (UPR), which is a cytoprotective response against ER stress, in yeast Saccharomyces cerevisiae. An S. cerevisiae mutant carrying a UPR-deficient mutation was hypersensitive to prodigiosin. Our observations cumulatively indicate that protein folding in the ER is impaired by prodigiosin, illustrating a new mode of action.

AHL-Based Quorum Sensing Regulates the Biosynthesis of a Variety of Bioactive Molecules in Bacteria

Bacteria are social microorganisms that use communication systems known as quorum sensing (QS) to regulate diverse cellular behaviors including the production of various secreted molecules. Bacterial secondary metabolites are widely studied for their bioactivities including antibiotic, antifungal, antiparasitic, and cytotoxic compounds. Besides playing a crucial role in natural bacterial niches and intermicrobial competition by targeting neighboring organisms and conferring survival advantages to the producer, these bioactive molecules may be of prime interest to develop new antimicrobials or anticancer therapies. This review focuses on bioactive compounds produced under acyl homoserine lactone-based QS regulation by Gram-negative bacteria that are pathogenic to humans and animals, including the Burkholderia, Serratia, Pseudomonas, Chromobacterium, and Pseudoalteromonas genera. The synthesis, regulation, chemical nature, biocidal effects, and potential applications of these identified toxic molecules are presented and discussed in light of their role in microbial interactions.

Red bioactive pigment from Himalayan Janthinobacterium sp. ERMR3:09: optimization, characterization, and potential applications

Prodigiosin is a red pigment commonly produced as a secondary metabolite by Serratia marcescens. It exhibits inherent bioactivities, including antimicrobial and anticancer, with low to no toxic effects on normal cells. The present study investigates a bioactive prodigiosin production from an atypical, red-pigmented, potentially novel Janthinobacterium sp. ERMR3:09 isolated from a glacial moraine. Statistically optimized culture parameters, i.e., w/v 1.0% glucose and 0.08% peptone as carbon and nitrogen sources, temperature 20 °C, and media pH 7, resulted in a four-fold increase in the pigment yield. The upscaled production in an 8 L volume resulted in higher pigment production within a shorter period of 48 h. The ultra-performance liquid chromatography (UPLC) analysis validated the identity of the purified pigment as prodigiosin that showed thermostability at 75 °C for 3 h. Evaluation of antimicrobial activity showed potent inhibitory effects (> 50%) against the opportunistic pathogenic fungal and Gram-positive bacterial strains. The pigment showed significant cytotoxicity (p < 0.05) towards A549 and HeLa cell lines with IC50 values of 42.2 μM and 36.11 μM, respectively. The study demonstrated that microbial communities from extreme niches can be ideal sources of bioactive pigments with immense pharmaceutical potential vital for the development of non-synthetic therapeutic agents.

Development of a bacterial gene transcription activating strategy based on transcriptional activator positive feedback

INTRODUCTION

Transcription of biological nitrogen fixation (nif) genes is activated by the NifA protein which recognizes specific activating sequences upstream of σ54-dependent nif promoters. The large quantities of nitrogenase which can make up 20% of the total proteins in the cell indicates high transcription activating efficiency of NifA and high transcription level of nifHDK nitrogenase genes.

OBJECTIVES

Development of an efficient gene transcription activating strategy in bacteria based on positive transcription regulatory proteins and their regulating DNA sequences.

METHODS

We designed a highly efficient gene transcription activating strategy in which the nifA gene was placed directly downstream of its regulating sequences. The NifA protein binds its regulating sequences and stimulates transcription of itself and downstream genes. Overexpressed NifA causes transcription activation by positive reinforcement.

RESULTS

When this gene transcription activating strategy was used to overexpress NifA in Pseudomonas stutzeri DSM4166 containing the nif gene cluster, the nitrogenase activity was increased by 368 folds which was 16 times higher than that obtained by nifA driven by the strongest endogenous constitutive promoter. When this strategy was used to activate transcription of exogenous biosynthetic genes for the plant auxin indole-3-acetic acid and the antitumor alkaloid pigment prodigiosin in DSM4166, both of them resulted in better performance than the strongest endogenous constitutive promoter and the highest reported productions in heterologous hosts to date. Finally, we demonstrated the universality of this strategy using the positive transcriptional regulator of the psp operon, PspF, in E. coli and the pathway-specific positive transcription regulator of the polyene antibiotic salinomycin biosynthesis, SlnR, in Streptomyces albus.

CONCLUSION

Many positive transcription regulatory proteins and their regulating DNA sequences have been identified in bacteria. The gene transcription activating strategy developed in this study will have broad applications in molecular biology and biotechnology.

In silico exploration of Serratia sp. BRL41 genome for detecting prodigiosin Biosynthetic Gene Cluster (BGC) and in vitro antimicrobial activity assessment of secreted prodigiosin

The raising concern of drug resistance, having substantial impacts on public health, has instigated the search of new natural compounds with substantial medicinal activity. In order to find out a natural solution, the current study has utilized prodigiosin, a linear tripyrrole red pigment, as an active ingredient to control bacterial proliferation and prevent cellular oxidation caused by ROS (Reactive Oxygen Species). A prodigiosin-producing bacterium BRL41 was isolated from the ancient Barhind soil of BCSIR Rajshahi Laboratories, Bangladesh, and its morphological and biochemical characteristics were investigated. Whole genome sequencing data of the isolate revealed its identity as Serratia sp. and conferred the presence of prodigiosin gene cluster in the bacterial genome. "Prodigiosin NRPS", among the 10 analyzed gene clusters, showed 100% similarity with query sequences where pigC, pigH, pigI, and pigJ were identified as fundamental genes for prodigiosin biosynthesis. Some other prominent clusters for synthesis of ririwpeptides, yersinopine, trichrysobactin were also found in the chromosome of BRL41, whilst the rest displayed less similarity with query sequences. Except some first-generation beta-lactam resistance genes, no virulence and resistance genes were found in the genome of BRL41. Structural illumination of the extracted red pigment by spectrophotometric scanning, Thin-Layer Chromatography (TLC), Fourier Transform Infrared Spectroscopy (FTIR), and change of color at different pH solutions verified the identity of the isolated compound as prodigiosin. Serratia sp. BRL41 attained its maximum productivity 564.74 units/cell at temperature 30˚C and pH 7.5 in two-fold diluted nutrient broth medium. The compound exhibited promising antibacterial activity against Gram-positive and Gram-negative bacteria with MIC (Minimum Inhibitory Concentration) and MBC (Minimum Bactericidal Concentration) values ranged from 3.9 to15.62 μg/mL and 7.81 to 31.25 μg/mL respectively. At concentration 500 μg/mL, except in Salmonella enterica ATCC-10708, prodigiosin significantly diminished biofilm formed by Listeria monocytogens ATCC-3193, Pseudomonas aeruginosa ATCC-9027, Escherichia coli (environmental isolate), Staphylococcus aureus (environmental isolate). Cellular glutathione level (GSH) was elevated upon application of 250 and 500 μg/mL pigment where 125 μg/mL failed to show any free radical scavenging activity. Additionally, release of cellular components in growth media of both Gram-positive and Gram-negative bacteria were facilitated by the extract that might be associated with cell membrane destabilization. Therefore, the overall findings of antimicrobial, antibiofilm and antioxidant activities suggest that in time to come prodigiosin might be a potential natural source to treat various diseases and infections.

Transcriptomic analysis of the antimicrobial activity of prodigiosin against Cutibacterium acnes

Prodigiosin, a red pigment produced by Hahella chejuensis, a marine-derived microorganism, has several biological functions, including antimicrobial activity and inflammatory relief. In this study, the antibacterial activity of prodigiosin against skin microorganisms was explored. Paper disc assay on skin bacterial cells revealed that Cutibacterium acnes related to acne vulgaris highly susceptible to prodigiosin. MIC (Minimal Inhibitory Concentration) and MBC (Minimal Bactericidal Concentration) were determined on Cutibacterium species. The RNA-seq analysis of prodigiosin-treated C. acnes cells was performed to understand the antibacterial mechanism of prodigiosin. Among changes in the expression of hundreds of genes, the expression of a stress-responsive sigma factor encoded by sigB increased. Conversely, the gene expression of cell wall biosynthesis and energy metabolism was inhibited by prodigiosin. Specifically, the expression of genes related to the metabolism of porphyrin, a pro-inflammatory metabolite, was significantly reduced. Therefore, prodigiosin could be used to control C. acnes. Our study provided new insights into the antimicrobial mechanism of prodigiosin against C. acnes strains.

Antioxidant prodigiosin-producing cold-adapted Janthinobacterium sp. ERMR3:09 from a glacier moraine: Genomic elucidation of cold adaptation and pigment biosynthesis

Janthinobacterium from cold niches has been studied broadly for bioactive violacein production. However, reports on the atypical red-pigmented Janthinobacterium strains are shallow. The bioactive red prodigiosin pigment has immense pharmacological significance, including antioxidant, antimicrobial and anticancer potential. Here, we report the first complete genome of a prodigiosin-producing Janthinobacterium sp. ERMR3:09 from Sikkim Himalaya in an attempt to elucidate its cold adaptation and prodigiosin biosynthesis. Nanopore sequencing and Flye assembly of the ERMR3:09 genome resulted in a single contig of 6,262,330 bp size and 62.26% GC content. Phylogenomic analysis and genome indices indicate that ERMR3:09 is a potentially novel species of the genus Janthinobacterium. The multicopy cold-responsive genes and gene upregulation under cold stress denoted its cold adaptation mechanisms. Genome analysis identified the unique genes, gene cluster and pathway for prodigiosin biosynthesis in ERMR3:09. Considering the notable antioxidant activity, it can be the next powerhouse of bioactive prodigiosin production.

Advancing PHBV Biomedical Potential with the Incorporation of Bacterial Biopigment Prodigiosin

The quest for sustainable biomaterials with excellent biocompatibility and tailorable properties has put polyhydroxyalkanoates (PHAs) into the research spotlight. However, high production costs and the lack of bioactivity limit their market penetration. To address this, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) was combined with a bacterial pigment with strong anticancer activity, prodigiosin (PG), to obtain functionally enhanced PHBV-based biomaterials. The samples were produced in the form of films 115.6-118.8 µm in thickness using the solvent casting method. The effects of PG incorporation on the physical properties (morphology, biopolymer crystallinity and thermal stability) and functionality of the obtained biomaterials were investigated. PG has acted as a nucleating agent, in turn affecting the degree of crystallinity, thermal stability and morphology of the films. All samples with PG had a more organized internal structure and higher melting and degradation temperatures. The calculated degree of crystallinity of the PHBV copolymer was 53%, while the PG1, PG3 and PG3 films had values of 64.0%, 63.9% and 69.2%, respectively. Cytotoxicity studies have shown the excellent anticancer activity of films against HCT116 (colon cancer) cells, thus advancing PHBV biomedical application potential.

Hyperspectral Visualization-Based Mass Spectrometry Imaging by LMJ-SSP: A Novel Strategy for Rapid Natural Product Profiling in Bacteria

Mass spectrometry imaging (MSI) has been widely used to discover natural products (NPs) from underexplored microbiological sources. However, the technique is limited by incompatibility with complicated/uneven surface topography and labor-intensive sample preparation, as well as lengthy compound profiling procedures. Here, liquid micro-junction surface sampling probe (LMJ-SSP)-based MSI is used for rapid profiling of natural products from Gram-negative marine bacteria Pseudoalteromonas on nutrient agar media without any sample preparation. A conductance-based autosampling platform with 1 mm spatial resolution and an innovative multivariant analysis-driven method was used to create one hyperspectral image for the sampling area. NP discovery requires general spatial correlation between m/z and colony location but not highly precise spatial resolution. The hyperspectral image was used to annotate different m/z by straightforward color differences without the need to directly interrogate the spectra. To demonstrate the utility of our approach, the rapid analysis of Pseudoalteromonas rubra DSM6842, Pseudoalteromonas tunicata DSM14096, Pseudoalteromonas piscicida JCM20779, and Pseudoalteromonas elyakovii ATCC700519 cultures was directly performed on Agar. Various natural products, including prodiginine and tambjamine analogues, were quickly identified from the hyperspectral image, and the dynamic extracellular environment was shown with compound heatmaps. Hyperspectral visualization-based MSI is an efficient and sensitive strategy for direct and rapid natural product profiling from different Pseudoalteromonas strains.

Sustainable strategies for management of the "false root-knot nematode" Nacobbus spp

The genus Nacobbus, known as the false root-knot nematode, is native to the American continent and comprises polyphagous species adapted to a wide range of climatic conditions. Alone or in combination with other biotic and abiotic factors, Nacobbus spp. can cause significant economic yield losses on main food crops such as potato, sugar beet, tomato, pepper and bean, in South and North America. Although the genus distribution is restricted to the American continent, it has quarantine importance and is subject to international legislation to prevent its spread to other regions, such as the European Union. The management of Nacobbus spp. remains unsatisfactory due to the lack of information related to different aspects of its life cycle, survival stages in the soil and in plant material, a rapid and reliable diagnostic method for its detection and the insufficient source of resistant plant genotypes. Due to the high toxicity of chemical nematicides, the search for alternatives has been intensified. Therefore, this review reports findings on the application of environmentally benign treatments to manage Nacobbus spp. Biological control strategies, such as the use of different organisms (mainly bacteria, fungi and entomopathogenic nematodes) and other eco-compatible approaches (such as metabolites, essential oils, plant extracts, phytohormones and amendments), either alone or as part of a combined control strategy, are discussed. Knowledge of potential sources of resistance for genetic improvement for crops susceptible to Nacobbus spp. are also reported. The sustainable strategies outlined here offer immediate benefits, not only to counter the pathogen, but also as good alternatives to improve crop health and growth.

In vitro study of the modulatory effects of heat-killed bacterial biomass on aquaculture bacterioplankton communities

Recent studies have shown that the addition of non-viable microbial biomass or their components (postbiotics) to fish feed can modulate the gut microbiome and positively influence fish health in aquaculture systems. However, no information was hitherto available on the use of non-viable microbial biomass to manipulate aquaculture bacterioplankton communities. To fill this gap, here we used an in vitro model to assess the effects of heat-killed biomasses of an antagonistic strain Pseudoalteromonas rubra SubTr2 and a non-antagonist strain Escherichia coli DH5α on bacterioplankton communities of a recirculating aquaculture system (RAS). Our results showed that these biomasses can have generalist and species-specific effects on aquaculture bacterioplankton structure and function. In addition, they enriched the abundance of bacterial predators, reduced bacterial load and potentially influenced nutrient cycling and pathogen development in aquaculture water. Despite its preliminary nature, for the first time, this study showed that heat-killed microbial biomass has potential application as an in situ modulator of bacterioplankton in aquaculture systems.

Synthesis, Anticancer Potential and Comprehensive Toxicity Studies of Novel Brominated Derivatives of Bacterial Biopigment Prodigiosin from Serratia marcescens ATCC 27117

Prodigiosins (prodiginines) are a class of bacterial secondary metabolites with remarkable biological activities and color. In this study, optimized production, purification, and characterization of prodigiosin (PG) from easily accessible Serratia marcescens ATCC 27117 strain has been achieved to levels of 14 mg/L of culture within 24 h. Furthermore, environmentally friendly bromination of produced PG was used to afford both novel mono- and dibrominated derivatives of PG. PG and its Br derivatives showed anticancer potential with IC₅₀ values range 0.62–17.00 µg/mL for all tested cancer cell lines and induction of apoptosis but low selectivity against healthy cell lines. All compounds did not affect Caenorhabditiselegans at concentrations up to 50 µg/mL. However, an improved toxicity profile of Br derivatives in comparison to parent PG was observed in vivo using zebrafish (Danio rerio) model system, when 10 µg/mL applied at 6 h post fertilization caused death rate of 100%, 30% and 0% by PG, PG-Br, and PG-Br_2, respectively, which is a significant finding for further structural optimizations of bacterial prodigiosins. The drug-likeness of PG and its Br derivatives was examined, and the novel Br derivatives obey the Lipinski’s “rule of five”, with an exemption of being more lipophilic than PG, which still makes them good targets for further structural optimization.

Prodigiosin: a promising biomolecule with many potential biomedical applications

Pigments are among the most fascinating molecules found in nature and used by human civilizations since the prehistoric ages. Although most of the bio-dyes reported in the literature were discovered around the eighties, the necessity to explore novel compounds for new biological applications has made them resurface as potential alternatives. Prodigiosin (PG) is an alkaloid red bio-dye produced by diverse microorganisms and composed of a linear tripyrrole chemical structure. PG emerges as a really interesting tool since it shows a wide spectrum of biological activities, such as antibacterial, antifungal, algicidal, anti-Chagas, anti-amoebic, antimalarial, anticancer, antiparasitic, antiviral, and/or immunosuppressive. However, PG vehiculation into different delivery systems has been proposed since possesses low bioavailability because of its high hydrophobic character (XLogP3-AA = 4.5). In the present review, the general aspects of the PG correlated with synthesis, production process, and biological activities are reported. Besides, some of the most relevant PG delivery systems described in the literature, as well as novel unexplored applications to potentiate its biological activity in biomedical applications, are proposed.

Discovery of New Secondary Metabolites from Marine Bacteria Hahella Based on an Omics Strategy

Hahella is one characteristic genus under the Hahellaceae family and shows a good potential for synthesizing new natural products. In this study, we examined the distribution of the secondary metabolite biosynthetic gene cluster (SMBGC) under Hahella with anti-SMASH. The results derived from five genomes released 70 SMBGCs. On average, each strain contains 12 gene clusters, and the most abundant ones (45.7%) are from the family of non-ribosomal peptide synthetase (NRPS) and non-ribosomal peptide synthetase hybrid with polyketide synthase (NRPS/PKS), indicating a great potential to find bioactive compounds. The comparison of SMBGC between H. chejuensis and other species showed that H. chejuensis contained two times more gene clusters than H. ganghwensis. One strain, designed as NBU794, was isolated from the mangrove soil of Dongzhai Port in Haikou (China) by iChip. The 16S rRNA gene of NBU794 exhibited 99% identity to H. chejuensis KCTC 2396 and clustered with the H. chejuensis clade on the phylogenetic trees. Genome mining on strain NBU794 released 17 SMBGCs and two groups of bioactive compounds, which are chejuenolide A-C and nine prodiginines derivatives. The prodiginines derivatives include the well-known lead compound prodigiosin and two new compounds, 2-methyl-3-pentyl-4-O-methyl-prodiginine and 2-methyl-3-octyl-prodiginine, which were identified through fragmentation analysis based on LC-MS/MS. The anti-microbial activity assay showed prodigiosin and 2-methyl-3-heptyl-prodiginine exhibited the best performance in inhibiting Escherichia coli, Salmonella paratyphi B, MASA Staphylococcus aureus, Bacillus subtilis, and Candida albicans. Moreover, the yield of prodigiosin in H. chejuensis NBU794 was also evaluated, which could reach 1.40 g/L under the non-optimized condition and increase to 5.83 g/L in the modified ISP4 medium with macroporous adsorption beads added, indicating that NBU794 is a promising source of prodigiosin.

Lignocellulosic substrates as starting materials for the production of bioactive biopigments

The search for sustainable processes is constantly increasing in the last years, so reusing, recycling and adding value to residues and by-products from agroindustry is a consolidated area of research. Particularly in the field of fermentation technology, the lignocellulosic substrates have been used to produce a diversity of chemicals, fuels and food additives. These residues or by-products are rich sources of carbon, which may be used to yield fermentescible sugars upon hydrolysis, but are usually inaccessible to enzyme and microbial attack. Therefore, pre-treatments (e.g. hydrolysis, steam explosion, biological pretreatment or others) are required prior to microbial action. Biopigments are added-value compounds that can be produced biotechnologically, including fermentation processes employing lignocellulosic substrates. These molecules are important not only for their coloring properties, but also for their biological activities. Therefore, this paper discusses the most recent and relevant processes for biopigment production using lignocellulosic substrates (solid-state fermentation) or their hydrolysates.

Draft genome of Serratia sp. R1 gives an insight into the antibiotic resistant genes against multiple antibiotics

BACKGROUND

Serratia is a pathogenic bacterium, commonly associated with neonatal intensive care units, and harbors antibiotic-resistant genes against multiple antibiotics e.g., resistance against penams, aminoglycosides, tetracyclines, cephalosporins, and macrolides. In the long-term contaminated habitat, the bacterial communities carry both antibiotic and metal resistance genes. This draft genome sequencing aimed to explore the alarming level of ARGs in the environment, additionally heavy metal-resistant genes were also explored in the draft genome.

METHODS

Whole-genome sequencing was used to investigate ARGs in Serratia sp. R1. The bacteria were sequenced using Illumina Nova seq sequencer and subjected to genome annotation. The bacterial genome was explored for antibiotic- and metal-resistant genes.

RESULTS

Sequencing resulted in 8.4 Mb genome and a total of 4411 functional genes were characterized in the draft genome. Genes resistant to Beta-lactams, cephalosporins, macrolides, fluoroquinolones, and tetracycline are present in the draft genome. Multiple metal-resistant genes are also present in the sequenced genome.

CONCLUSION

The genes and proteins providing heavy metal and antibiotic resistance may be used in the bioremediation of environmental antibiotic residues to prevent the spread of antibiotic resistance. The current study can help us to adopt suitable mitigation measures against the multidrug-resistant Serratia.

Prodigiosin Production and Photoprotective/Antigenotoxic Properties in Serratia marcescens Indigenous Strains from Eastern Cordillera of Colombia

Serratia marcescens is a bacterial species that produces an antibacterial pigment (Prodigiosin) showing a wide adaptive response to environmental stresses. The study aimed to investigate Prodigiosin production in S. marcescens wild-type strains, as well as its relation to photoprotection and antigenotoxicity against UVB. Prodigiosin yield was spectrophotometrically assayed in extracts of bacterial strains grown in different culture media. In vitro photoprotection efficacy was evaluated using the in vitro indices sun protection factor (SPF_in vitro ) and critical wavelength (λc). The percentage of UVB antigenotoxicity estimates (%GI) in the SOS Chromotest was also evaluated. Correlation analysis was used to examine the relationship between Prodigiosin yield, SPF_in vitro , %GI estimates and environmental traits (altitude, temperature, rainfall and solar irradiance). Prodigiosin yield in S. marcescens strains varied depending on culture media used for its growth, and it was correlated with environmental variables such as temperature and solar irradiance. SPF_in vitro estimates were well correlated with Prodigiosin concentration and %GI values in the bacterial strains being studied. UVB photoprotective efficacy of the extracts obtained from S. marcescens strains depends on the strain's Prodigiosin yield and its antigenotoxic potential. The extracts with Prodigiosin yield higher than ˜17 μg mL^-1 could be used as sources of sunscreen ingredients.

Associations between cellular levels of ATP and prodigiosin pigment throughout the growth cycle of Serratia marcescens

Serratia marcescens is a prolific producer of the red, membrane-associated pigment prodigiosin. Earlier work has established both a positive role for prodigiosin in ATP production during the population lag phase and a negative role during high-rate, low cell density growth. This study uses the growth rate and growth phase modulation afforded by chemostat culture to extend prodigiosin functional analysis to the high-density and stationary phases. Cellular levels of prodigiosin were positively associated with cellular levels of ATP during high-density growth, and artificial pigment induction during this phase increased cellular ATP levels. Following peak high-density ATP per cell, the early stationary phase enabled significant population growth, while prodigiosin levels remained high and ATP declined. During the late stationary phase, ATP per cell was positively associated with prodigiosin per cell, while both declined during continued growth. These results provide correlational evidence for the multiple effects of prodigiosin pigment on ATP production throughout the growth cycle. Earlier work and the data presented here enable the formulation of a working model for the oscillating relationships between cellular levels of ATP and prodigiosin during batch culture.

Bioengineering of Anti-Inflammatory Natural Products

Inflammatory processes occur as a generic response of the immune system and can be triggered by various factors, such as infection with pathogenic microorganisms or damaged tissue. Due to the complexity of the inflammation process and its role in common diseases like asthma, cancer, skin disorders or Alzheimer's disease, anti-inflammatory drugs are of high pharmaceutical interest. Nature is a rich source for compounds with anti-inflammatory properties. Several studies have focused on the structural optimization of natural products to improve their pharmacological properties. As derivatization through total synthesis is often laborious with low yields and limited stereoselectivity, the use of biosynthetic, enzyme-driven reactions is an attractive alternative for synthesizing and modifying complex bioactive molecules. In this minireview, we present an outline of the biotechnological methods used to derivatize anti-inflammatory natural products, including precursor-directed biosynthesis, mutasynthesis, combinatorial biosynthesis, as well as whole-cell and in vitro biotransformation.