Dual activity of Serratia marcescens Pt-3 in phosphate-solubilizing and production of antifungal volatiles

Background Soil fertility decline and pathogen infection are severe issues for crop production all over the world. Microbes as inherent factors in soil were effective in alleviating fertility decrease, promoting plant growth and controlling plant pathogens et al. Thus, screening microbes with fertility improving and pathogen controlling properties is of great importance to humans. Results Bacteria Pt-3 isolated from tea rhizosphere showed multiple functions in solubilizing insoluble phosphate, promoting plant growth, producing abundant volatile organic compounds (VOCs) and inhibiting the growth of important fungal pathogens in vitro. According to the 16S rRNA phylogenetic and biochemical analysis, Pt-3 was identified to be Serratia marcescens. The solubilizing zone of Pt-3 in the medium of lecithin and Ca3(PO4)2 was 2.1 cm and 1.8 cm respectively. In liquid medium and soil, the concentration of soluble phosphorus reached 343.9 mg.L− 1, and 3.98 mg.kg− 1, and significantly promoted the growth of maize seedling, respectively. Moreover, Pt-3 produced abundant volatiles and greatly inhibited the growth of seven important phytopathogens. The inhibition rate ranged from 75.51 to 100% respectively. Solid phase micro-extraction coupled with gas chromatography tandem mass spectrometry proved that the antifungal volatile was dimethyl disulfide. Dimethyl disulfide can inhibit the germination of Aspergillus flavus, and severely destroy the cell structures under scanning electron microscopy. Conclusions S. marcescens Pt-3 with multiple functions will provide novel agent for the production of bioactive fertilizer with P-solubilizing and fungal pathogens control activity.

Genomic analysis and plant growth-promoting potential of a Serratia marcescens isolated from food

A genomic analysis of the potential application of a Serratia marcescens strain in the plant-growth promotion. We performed whole-genome sequencing of Serratia marcescens isolated from a Minas Frescal Cheese. The genomic repertoire revealed a bacterium of agricultural and biotechnological interest. In the plant-growth promotion traits, we highlight genes encoding proteins possibly responsible for the biosynthesis of phytohormone indole acetic acid, organic compounds that act in iron uptake, and the Phosphate solubilization system. Genes encoding for enzymes like the versatile L-asparaginase stimulates the development of seeds and grains and can benefit the food industry due to a mitigation effect on acrylamide and notably, has medical applications as a chemotherapeutic agent or is applicable by its antimicrobial and anti-inflammatory properties. Moreover, functional diversity of genes encoding for resistance to different metals and metabolism of xenobiotics genes can be found in this strain, reinforcing its biotechnological potential. The versatile enzymes that can be produced by S. marcescens benefit the food, pharmaceutical, textile, agronomic, and cosmetic industries. The relevant genetic systems of S. marcescens described here may be used to promote plant growth and health and improve the environment. To the best of our knowledge, this is the first genome sequence report on S. marcescens isolated from cheese, with potential application as promoting plant growth and providing a baseline for future genomic studies on the development of this species.

Debridement, antibiotics, and implant retention in infected shoulder arthroplasty caused by Serratia marcescens: a case report

Periprosthetic joint infection (PJI) is one of the most devastating complications that can occur after shoulder arthroplasty. Although staged revision arthroplasty is the standard treatment in many cases, surgical intervention with debridement, antibiotics, and implant retention (DAIR) can be an effective option for acute PJI. We report a complex case of infected reverse shoulder arthroplasty (RSA) in a 73-year-old male. The patient had been previously treated for infected nonunion of a proximal humerus fracture caused by methicillin-resistant Staphylococcus epidermidis. He presented with a sinus tract 16 days after the implantation of RSA and was diagnosed with PJI caused by Serratia marcescens. The patient was successfully treated with DAIR and was free of infection at the last follow-up visit at four years postoperatively.

Transcriptomic Analysis Reveals Competitive Growth Advantage of Non-pigmented Serratia marcescens Mutants

Serratia marcescens is a common bacterium well-known for the red secondary metabolite prodigiosin. However, color mutants have long been described. Non-pigmented strains can be found to exist both naturally and under laboratory conditions. It is unclear why S. marcescens loses prodigiosin synthesis capacity in certain conditions. In the present study, we find that the spontaneous color mutants arise within a few generations (about five passages) and rapidly replace the wild-type parent cells (about 24 passages), which indicates a growth advantage of the former. Although, the loss of prodigiosin synthesis genes (pigA-N) is frequently reported as the major reason for pigment deficiency, it was unexpected that the whole gene cluster is completely preserved in the different color morphotypes. Comparative transcriptomic analysis indicates a dramatic variation at the transcriptional level. Most of the pig genes are significantly downregulated in the color morphotypes which directly lead to prodigiosin dyssynthesis. Besides, the transcriptional changes of several other genes have been noticed, of which transcriptional regulators, membrane proteins, and nearly all type VI secretion system (T6SS) components are generally downregulated, while both amino acid metabolite and transport systems are activated. In addition, we delete the transcription regulator slyA to generate a non-pigmented mutant. The ΔslyA strain loses prodigiosin synthesis capacity, but has a higher cell density, and surprisingly enhances the virulence as an entomopathogen. These data indicate that S. marcescens shuts down several high-cost systems and activates the amino acid degradation and transport pathways at the transcriptional level to obtain extra resources, which provides new insights into the competitive growth advantage of bacterial spontaneous color mutants.

Antigenic properties of serration bacteriophages

The genus Serratia is one of the poorly studied among enterobacteria, which explains the interest in these microorganisms and bacteriophages active towards these microorganisms. The aim of this work was to study the antigenic properties of bacteriophages isolated by us from lysogenic cultures of serrations and from environmental objects. The work investigated 16 phages active against bacteria Serratia marcescens, isolated from various sources.

Antimicrobial activities of certain seaweeds from muddy shore places of kerala

A study was carried out to reveal the growth inhibitory effect of methanol crude extract (MCE) and methanol supernatant extract (MSE) of sea weeds: 1) Gracillaria corticata, 2) Hypnea musciforms, 3) Gelidium micropterum and 4) Hypnea valentiae against six bacterial pathogens, 1) Pseudomonas aeruginosa, 2) Bacillus licheniformis, 3) Serratia marcescens, 4) Aeromonas hydrophila, 5) Acinetobacter baumanii, 6) Escherichia coli and two fungal strains, 1) Aspergillus niger and 2) Candida albicans respectively. Well diffusion method using zone of inhibition as indicator for growth inhibition was adopted. The results showed that methanol extracts of seaweeds viz., Gracillaria corticata, Hypnea musciforms, and Hypnea valentiae prevented the growth of pathogenic bacteria and fungi. The effect on growth was observed as zone of inhibition, the diameter of which was indicated in the units of a millimeter. The growth of the bacterium, Serratia marcescens was affected by methanol supernatant extract of the three types of seaweeds, Gracillaria corticata, Hypnea musciforms, and Hypnea valentiae, and by the methanolic crude extract of Hypnea musciforms and Hypnea valentiae. However, the growths of other species of bacteria were not controlled by either of the extracts of the seaweeds except, Bacillus licheniformis which was controlled by only Gracillaria corticata. The growth of fungi: Aspergillus niger and Candida albicans were inhibited by the methanol extracts of Gracillaria corticata. Between the two forms of methanolic extracts i.e., supernatant and crude, the efficiency of the supernatant extract was greater than that of crude one. Further, among the three types of seaweeds which showed an effect on the growth of microbes, the level of the zone of inhibition caused by Gracillaria corticata was statistically higher than that of the other two, Hypnea musciforms, and Hypnea valentiae.

REMOCIÓN DE CADMIO Y PLOMO EN UN EFLUENTE MINERO DE TICAPAMPA-RECUAY, ANCASH CON BIOMASA SECA DE Serratia marcescens M8a-2T

En el presente trabajo se utilizó biomasa seca de Serratia marcescens M8a-2T con el objetivo de remover cadmio y plomo presentes en una muestra de efluente minero en concentraciones de 496,18 µg/L y 513,55 µg/L respectivamente. La optimización de la remoción de dichos metales se realizó usando la Metodología de Superficie de Respuesta (RSM) y el diseño experimental de Box-Behnken considerando las variables pH (2; 3 y 4), concentración de biomasa (1; 2 y 3 mg/mL) y tiempo de contacto (15; 30 y 45 minutos). El porcentaje máximo de remoción de cadmio que se obtuvo fue de 97,11% a pH 4, con 2 mg/mL de biomasa durante 45 minutos. Mientras que el porcentaje máximo de remoción de plomo fue de 98,63% a pH 4, con 1 mg/mL de biomasa durante 30 minutos de contacto. Los altos niveles de significancia (p<0.05) de los modelos de regresión y ANOVA obtenidos indican al pH como la variable de mayor influencia. La Metodología de Superficie de Respuesta demostró ser de mucha utilidad para optimizar procesos de biorremediación.