Bacterium Pseudomonas Research Articles

Hydrocarbon Degradation and Biodegraders in Oil Spillage Sites in Port Harcourt

Information on remediation of soils polluted from the activities of artisanal crude oil refining is lacking. The functional capability of the indigenous microbial community and prospects for recovery of important bio-resources has also not been explored. The aim of this study was to identify the hydrocarbon biodegrader present in oil spillage sites in Port Harcourt. Samples were taken from various sites (labelled ss1, ss2, ss3 and controls) in Port Harcourt and the samples were transported to the lab for bacteriological assessment. The samples were cultured in Nutrient agar and Basal Salt Medium (BSM). The total heterotrophic bacteria counts were enumerated by serially diluting the fluid sample. Microbial characterization was done based on morphological, physiological and biochemical tests. From the results, Pseudomonas species and Bacillus species were the probable isolated from the culture of hydrocarbon contaminated environment. The results also revealed increased compared to the control organism that maintained the same growth level throughout the 5 days of incubation, the isolated bacteria (Pseudomonas species and Bacillus species) had steady bacterial growth. This study has shown that Bacillus species and Pseudomonas aeroginosa are potential agents of bioremediation of environmental hydrocarbon pollution.

The Use of Bacteria, Actinomycetes and Fungi in the Bioprotection of Solanaceous Crops against Tobacco Mosaic Virus (TMV)

Tobacco mosaic virus (TMV) is one of the most persistent and infectious plant viruses. The substantial economic losses caused by TMV in the production of tobacco and vegetables (especially in the Solanaceae family) are prompting the introduction of innovative solutions that effectively inhibit infection by this pathogen. Biological control agents based on bacteria of the genera Pseudomonas, Bacillus, Pantoea and actinomycetes are becoming increasingly popular in the fight against TMV. Some fungi, including Fusarium spp., Trichoderma spp., Alternaria spp. and Sepedonium spp., as well as wood-rotting fungi, also exhibit high anti-TMV activity. This article presents a comprehensive review of recent scientific advances in the bioprotection of selected solanaceous crops against TMV. It provides information on the structure of the virus, its host range, pathogenicity and the severity of losses caused in pepper, tomato and tobacco production. The review characterises environmentally safe techniques involving biological control agents naturally occurring in the environment and the bioactive compounds extracted from them. It also identifies their effects on crops at the morphological, physiological and molecular levels. In addition, the manuscript outlines prospects for the future applications of beneficial micro-organisms and active compounds derived from them in the protection against TMV.

Kraft Lignin Decomposition by Forest Soil Bacterium Pseudomonas kribbensis CHA-19.

Identification of the biochemical metabolic pathway for lignin decomposition and the responsible degradative enzymes is needed for the effective biotechnological valorization of lignin to renewable chemical products. In this study, we investigated the decomposition of kraft lignin by the soil bacterium Pseudomonas kribbensis CHA-19, a strain that can utilize kraft lignin and its main degradation metabolite, vanillic acid, as growth substrates. Gel permeation chromatography revealed that CHA-19 decomposed polymeric lignin and degraded dehydrodivanillin (a representative lignin model compound); however, the degradative enzyme(s) and mechanism were not identified. Quantitative polymerase chain reaction with mRNAs from CHA-19 cells induced in the presence of lignin showed that the putative genes coding for two laccase-like multicopper oxidases (LMCOs) and three dye-decolorizing peroxidases (DyPs) were upregulated by 2.0- to 7.9-fold compared with glucose-induced cells, which indicates possible cooperation with multiple enzymes for lignin decomposition. Computational homology analysis of the protein sequences of LMCOs and DyPs also predicted their roles in lignin decomposition. Based on the above data, CHA-19 appears to initiate oxidative lignin decomposition using multifunctional LMCOs and DyPs, producing smaller metabolites such as vanillic acid, which is further degraded via ortho- and meta-ring cleavage pathways. This study not only helps to better understand the role of bacteria in lignin decomposition and thus in terrestrial ecosystems, but also expands the biocatalytic toolbox with new bacterial cells and their degradative enzymes for lignin valorization.

As(III)-oxidizing and plant growth-promoting bacteria increase the starch biosynthesis-related enzyme activity, 2-AP levels, and grain quality of arsenic-stressed rice plants

BackgroundGrain quality is an important index of rice production, particularly when plants are grown under stress. Arsenic (As) contamination in paddy fields severely affects rice grain yield and quality. Here, the effects of As and combinations of As(III)-oxidizing bacteria (Pseudomonas stutzeri 4.25, 4.27, and 4.44) and plant growth-promoting bacteria (Delftia acidovorans KKU2500-12 and Cupriavidus taiwanensis KKU2500-3) on enzymes related to starch accumulation in grains and the grain quality of Khao Dawk Mali 105 rice cultivated in As-contaminated soil under greenhouse conditions were investigated.ResultsArsenic affected the activities of starch biosynthesis-related enzymes, and decreases of up to 76.27%, 71.53%, 49.74%, 73.39%, and 47.46% in AGPase, SSS, GBSS, SBE, and SDBE activities, respectively, and 9.42–61.07% in starch accumulation in grains were detected after growth in As-contaminated soil. However, the KKU2500-3/4.25 and KKU2500-3/4.44 combinations yielded the greatest enzyme activities in grains, and compared with the results observed in uninoculated seedlings, increases in starch accumulation of up to 51.16% and 23.81% were found in the inoculated seedlings after growth in medium- and high-As-contaminated soils, at 10–17 and 10–24 days after anthesis, respectively. The bacteria increased the 2-AP content in rice under As stress, possibly via the induction of proline, a 2-AP substrate. Bacterium-inoculated rice had significantly greater 2-AP levels than uninoculated rice, and 2.16–9.93% and 26.57–42.04% increases were detected in rice plants grown in medium- and high-As-contaminated soils, respectively.ConclusionsArsenic toxicity can be mitigated in rice growing under greenhouse conditions by maintaining starch biosynthesis, accumulating amylose, and increasing 2-AP content. The effectiveness of these bacteria should be validated in paddy fields; hence, safe rice grains with a good starch content and aroma could be produced.

Cooperative effects of three preservatives on physiological quality, endophytic bacterial community and volatile organic compounds of postharvest Codonopsis pilosula var. modesta roots.

Codonopsis pilosula var. modesta (CPVM) is a famous medicinal and edible plant of Campanulaceae. However, fresh CPVM roots (FCPVR) are prone to softening, browning and spoilage after concentrated harvesting in the main production area of Gansu Province, China in autumn, which poses great challenges to their large-scale storage and modern processing. In this study, effects of chitosan (CS), natamycin (NA) and modified atmosphere agent (MA) on the postharvest quality of FCPVR were first investigated. The roots after different treatments were stored at 4 °C and relative humidity of 75 ± 5% for 100 days. Their overall quality changes were evaluated from three perspectives: physiological quality, endophytic bacterial community and volatile organic compounds. The clustering heatmap and principal component analysis results indicated that CS (2 g kg-1), NA (0.5 g kg-1) and MA (5 g) had a synergistic effect on physiological quality. The roots in the CS + NA + MA group maintained better physiological state, effective components and antioxidant capacity throughout the storage process. On this basis, compared with room temperature storage, the relative abundance of the main spoilage bacterium Pseudomonas in the CS + NA + MA group roots decreased by 44% on the 100th day of storage. Furthermore, after CS + NA + MA composite treatment, the roots produced richer esters with fruit aroma during low-temperature storage. The CS + NA + MA composite treatment could maintain the physiological quality and flavor of FCPVR, inhibit spoilage by microbial contamination and maintain the optimal quality during low-temperature storage for up to 100 days. © 2024 Society of Chemical Industry.

Expanding the Pseudomonas diversity of the wheat rhizosphere: four novel species antagonizing fungal phytopathogens and with plant-beneficial properties.

Plant-beneficial Pseudomonas bacteria hold the potential to be used as inoculants in agriculture to promote plant growth and health through various mechanisms. The discovery of new strains tailored to specific agricultural needs remains an open area of research. In this study, we report the isolation and characterization of four novel Pseudomonas species associated with the wheat rhizosphere. Comparative genomic analysis with all available Pseudomonas type strains revealed species-level differences, substantiated by both digital DNA-DNA hybridization and average nucleotide identity, underscoring their status as novel species. This was further validated by the phenotypic differences observed when compared to their closest relatives. Three of the novel species belong to the P. fluorescens species complex, with two representing a novel lineage in the Pseudomonas phylogeny. Functional genome annotation revealed the presence of specific features contributing to rhizosphere colonization, including flagella and components for biofilm formation. The novel species have the genetic potential to solubilize nutrients by acidifying the environment, releasing alkaline phosphatases and their metabolism of nitrogen species, indicating potential as biofertilizers. Additionally, the novel species possess traits that may facilitate direct promotion of plant growth through the modulation of the plant hormone balance, including the ACC deaminase enzyme and auxin metabolism. The presence of biosynthetic clusters for toxins such as hydrogen cyanide and non-ribosomal peptides suggests their ability to compete with other microorganisms, including plant pathogens. Direct inoculation of wheat roots significantly enhanced plant growth, with two strains doubling shoot biomass. Three of the strains effectively antagonized fungal phytopathogens (Thielaviopsis basicola, Fusarium oxysporum, and Botrytis cinerea), demonstrating their potential as biocontrol agents. Based on the observed genetic and phenotypic differences from closely related species, we propose the following names for the four novel species: Pseudomonas grandcourensis sp. nov., type strain DGS24T ( = DSM 117501T = CECT 31011T), Pseudomonas purpurea sp. nov., type strain DGS26T ( = DSM 117502T = CECT 31012T), Pseudomonas helvetica sp. nov., type strain DGS28T ( = DSM 117503T = CECT 31013T) and Pseudomonas aestiva sp. nov., type strain DGS32T ( = DSM 117504T = CECT 31014T).

In vivo toxicity evaluation and antibacterial assessment of vanadium doped Bi2Se3 synthesized by cost effective method

Bismuth selenide-based nanomaterials are introduced as theranostic agents, primarily enhancing their antimicrobial, anti-cancerous, antitumor, and antioxidant properties. Pure Bi2Se3 and V doped Bi2Se3 with V = 0.07 g, 0.12 g, and 0.15 g were synthesized by using Sol-gel Technique. X-ray Diffraction (XRD) patterns demonstrated that the manufactured samples were crystalline in nature having rhombohedral structure. The average crystallite sizes of VxBi2-xS3 were calculated by Scherrer formula in the range (24.9–11.0 nm). The average crystallite size reduced as doping concentrations increased (0–0.15 g). The FTIR (Fourier transform infrared) spectra confirms that the peaks corresponds to 900–600 cm−1 indicates Bi–Se bond stretching, whereas vibrations exhibit peaks between 704 cm−1 - 830 cm−1 in doped samples correspond to V–O bond. UV–Visible analysis shows that the band gap of doped Bi2Se3 increased from (2.57 eV–2.90 eV) having standard error 0.02, 0.01, 0.02, and 0.02 respectively as the concentrations of doping increased (0.0–0.15 g), respectively. SEM (Scanning electron microscopy) study of pure Bi2Se3 showed nanosized particles, and for doped, a clear change in morphology occurred with the particles tending to agglomerate. EDAX also confirms the purity of synthesized samples. XPS analysis confirms the presence of Bi, Se and Vanadium along with chemisorbed oxygen. Antibacterial potential of synthesized samples was analyzed against Pseudomonas, Escherichia coli and cocci bacteria, which showed that the vanadium doped bismuth selenide has greater zone of inhibition than undoped bismuth selenide. Pseudomonas shows more ZOI (Zone of Inhibition) than E.coli and cocci. The maximum inhibition zone was 25 mm against Pseudomonas for V0.15Bi1.85Se3. The In-Vivo toxicity experiment was also applied on mice's (Swiss Albino) with a higher dosage of 20 mg per kg of the prepared doped sample. The blood samples were collected and examined after 3rd, 7th, 14th and 21st day of treatment. The entire treatment does not cause any severe damage to mice. An evaluation of a p-value based on hematological and biochemical data was non-significant this ensures that vanadium doped Bi2Se3 nanoparticles are non-toxic and biocompatible. This work proves that V-doped Bi2Se3 is good for further study in many other Applications in the biomedical field, such as photo thermal therapy, imaging etc.

Effect of Effective Microorganisms on Vegetative Growth of Wheat

Background: environmental pollution has led to climate change and agriculture is an aspect of this pollution, Pesticides, fertilizers and plant growth regulators are pollutants in soil and water. Therefore, beneficial microorganisms found in nature to provide plants with nutrients, resist pests and reduce mineral fertilizers is an ambitious goal for researchers. On the environment. Pseudomonas bacteria, baker’s yeast and mycorrhizal fungi are known for their ability to increase a group of nutrients’ organic and amino acids, as well as plant hormones that stimulate growth. Methods: A field experiment was conducted at University of Baghdad to assess the impact of beneficial microorganisms on wheat growth traits during winter Of 2019-2020., using a randomized complete block design (RCBD) with eight treatments.: Pseudomonas fluorescens bacteria (Pse), Mycorrhizae Glomusspp. (Gl.), Saccharomyces cerevisiae yeast (Sa.), Ps+Gl, Gl+Sa, Ps+Sa, Ps+Sa+Gl and control. Result: Experimental indicated that treatments significantly outperformed in plant height, tiller number, CGR (crop growth rate) and total dry weight. Additionally, the Ps+Sa+Gl treatment demonstrated a significant superiority over all other treatments in terms of plant height and tiller number. These observations suggest that the combination of biological factors within a single treatment resulted in a synergistic interaction, that led to enhancement of the vegetative growth indices in wheat plants.

Algae promotes the biogenic oxidation of Mn(II) by accelerated extracellular superoxide production

Microbial manganese (Mn) oxidation, predominantly occurs within the anaerobic-aerobic interfaces, plays an important role in environmental pollution remediation. The anaerobic-aerobic transition zones, notably riparian and lakeside zones, are hotspots for algae-bacteria interactions. Here, we adopted a Mn(II)-oxidizing bacterium Pseudomonas sp. QJX-1 to investigate the impact of algae on microbial Mn(II) oxidation and verify the underlying mechanisms. Interestingly, we achieved a remarkable enhancement in bacterial Mn(II)-oxidizing activity within the algae-bacteria co-culture, despite the inability to oxidize Mn(II) for the algae used in this study. In addition, the bacterial density almost remains constant in the presence of algal cells. Therefore, the increased Mn(II) oxidation by QJX-1 in the presence of algae cannot be due to the increased biomass. Within this co-culture system, the Mn(II) oxidation rate surged to an impressive 0.23 mg/L/h, in stark contrast to 0.02 mg/L/h recorded within pure QJX-1 system. The presence of algae could inhibit the Fe-S cluster activity of QJX-1 by the produced active substance in co-culture, and result in the acceleration of extracellular superoxide production due to the impairment of electron transfer functions located in QJX-1 cell membranes. Moreover, elevated peroxidase gene expression and heightened extracellular catalase activity not only expedited Mn(II) ions oxidation but also facilitated conversion of intermediate Mn(III) ions into microbial Mn oxides, achieved through the degradation of hydrogen peroxide. Therefore, the acceleration of extracellular superoxide production and the decomposition of hydrogen peroxide are identified as the principal mechanisms behind the observed enhancement in Mn(II) oxidation within algae-bacteria co-cultures. Our findings highlight the need to consider the effect of algae on microbial Mn(II) oxidation, which plays an important role in the environmental pollution remediation.

Effect of VP, MAP and combined packaging systems on the physicochemical properties and microbiological status of veal from unweaned calves

The packaging system is one of the factors influencing the preservation of the nutritional value, microbiological safety, and sensory attributes of meat. The study investigated changes in physicochemical and microbiological properties taking place during 15-day refrigerated storage of two calf muscles, the longissimus lumborum (LL) and semitendinosus (ST), packaged in three systems, respectively, vacuum packing (VP), modified atmosphere packaging (MAP, 80% O2 + 20% CO2), and a combined system (VP + MAP, 8 d in VP followed by 7 d in MAP). LL and ST stored in VP had significantly lower levels of lipid oxidation, higher α-tocopherol content, and higher instrumentally measured tenderness in comparison with the samples stored in MAP. On the other hand, the MAP samples had lower purge loss at 5 and 15 days, a higher proportion of oxymyoglobin up to 10 days of storage, and a better microbiological status. Calf muscle samples stored in the VP + MAP system had intermediate values for TBARS and α-tocopherol content and at the same time were the most tender and had the lowest counts of Pseudomonas and Enterobacteriaceae bacteria at 15 days. All packaging systems ensured relatively good quality of veal characteristics up to the last day of storage. However, for MAP at 15 days of storage, unfavourable changes in colour (a high level of metmyoglobin and a decrease in oxymyoglobin, redness and R630/580 ratio) and in the lipid fraction (a high TBARS value and a significant decrease in α-tocopherol content) were observed.

The effectiveness of garlic extracts on biogenic amine formation by foodborne pathogens and fish spoilage bacteria

SummaryImpacts of aqueous and ethanolic extracts of garlic were investigated in suppressing bacterial growth and biogenic amine (BA) formation by selected foodborne pathogens (Candida albicans, Salmonella paratyphi A, Escherichia coli and Staphylococcus aureus) and fish spoilage bacteria (Enterococcus faecalis, Photobacterium damselae and Pseudomonas luteola). The spread‐plate method was used to monitor bacterial growth in histidine decarboxylase broth (HDB), whereas the rapid high‐performance liquid chromatographic (HPLC) method was used for BA analysis. Bacterial growth and their ammonia and BA production were monitored using HDB. The results showed that bacterial growth on HDB was in the range from 9.13, for P. luteola, to 9.54 log CFU (colony‐forming units) mL−1, for S. aureus and C. albicans. The presence of garlic extracts in HDB resulted considerably in lowering bacterial growth and BA formation (P < 0.05). The highest inhibitory activities of ethanolic and water garlic extracts were obtained for Gram‐positive S. aureus with 1.4 and 1.5 logarithmic reduction on bacterial growth, followed by Gram‐negative Salmonella Paratyphi A and E. coli. Application of garlic extracts, mainly ethanolic ones, showed a significant inhibitory effect on bacterial ammonia production, with 4‐100‐fold lower ammonia accumulation (P < 0.05). Bacteria produced all tested BAs, mainly dopamine, agmatine and tryptamine. The highest levels of histamine and tyramine (61.99 and 36.45 mg L−1) were produced by S. aureus. In the presence of aqueous or ethanolic garlic extracts, putrescine production by E. faecalis was around 110‐fold lower than that of the control group. Results revealed that both garlic extracts are potent antimicrobials that can control the growth of foodborne pathogens and their harmful BA formation.

تثبيط تكوين الاغشية الحيوية في بكتيريا Agrobacterium tumefaciens بالمادة الطافية الخالية من خلايا Pseudomonas aeruginosa والمحللة بجهاز GC-MS

تعد Agrobacterium tumefaciens من أنواع البكتيريا المسببة للأمراض النباتية المهمة اقتصاديا، وتحصل الاصابة نتيجة استخدام اغشيتها الحيوية لالصاق نفسها بالجروح المتكونة على سطح العائل النباتي، ونظرًا لمحدودية العلاجات الحالية وفعاليتها، أصبح البحث عن عوامل جديدة مضادة لهذه البكتيريا أمرا ضروريا، لذلك تم تسليط الضوء في هذه الدراسة على معرفة التأثير التثبيطي للمادة الطافية الخالية من خلايا Pseudomonas aeruginosa على تكوين الاغشية الحيوية من قبل A. tumefaciens، فضلا عن تحديد المركبات الكيمياوية المكونة لها بجهاز GC-MS. بناءا على ذلك عزلت P. aeruginosa من التربة وتم تشخيصها باستخدام العدةAPI 20 E وتفاعل البلمرة المتسلسل باستخدام الجين 16S rRNA واظهرت تطابقا بنسبة 93% مع البكتيريا القياسية Pseudomonas sp.SeaQual P_B_845W, MT626817.1 في بنك الجينات. وعند الكشف عن قدرة المادة الطافية المجفدة وبتسعة تراكيز10، 15، 20 ،25 ، 30، 35، 40، 45، 17، 17، 15 ،على التوالي. وحسب عدد القمم التي تم إنتاجها بعد حقنها بجهاز GC، تبين انها مكونة من 30 مادة كيميائية، وبعد إدخال هذه المعلومات في جهاز MS، تم تشخيصها بأسمائها ومنها(Pyrrolo[1,2-a]pyrazine-1,4-dione, hexahydro-، Hexadecanoic acid, methyl ester، Pyrrolo[1,2-a]pyrazine-1,4-dione, hexahydro-3-(2-methylpropyl)-،9-Octadecenoic acid (Z)-,methyl ester،cis-13-Octadecenoic acid,methyl ester،Octadecanoic acid, methyl ester)، البالغ وزنها الجزيئي(154، 270، 210، 296، 296، 298) دالتون ومقدار المساحة التي تشغلها (9.38، 19.12، 6.8، 4.45، 8.33، 5.90)%، على التوالي. أهم النتائج التي شخصتها هذه الدراسة هو تحديد المركبات الكيميائية لأول مرة للمادة الطافية الخالية من خلايا الزائفة الزنجارية وتأثيرها المثبط على إنتاج الأغشية الحيوية من قبل A. tumefaciens.

Weather-related changes in the dehydration of respiratory droplets on surfaces bolster bacterial endurance

HypothesisThe study shows for the first time a fivefold difference in the survivability of the bacterium Pseudomonas Aeruginosa (PA) in a realistic respiratory fluid droplet on fomites undergoing drying at different environmental conditions. For instance, in 2023, the annual average outdoor relative humidity (RH) and temperature in London (UK) is 71 % and 11 °C, whereas in New Delhi (India), it is 45 % and 26 °C, showing that disease spread from fomites could have a demographic dependence. Respiratory fluid droplet ejections containing pathogens on inanimate surfaces are crucial in disease spread, especially in nosocomial settings. However, the interplay between evaporation dynamics, internal fluid flow and precipitation and their collective influence on the distribution and survivability of pathogens at different environmental conditions are less known. ExperimentsShadowgraphy imaging is employed to study evaporation, and optical microscopy imaging is used for precipitation dynamics. Micro-particle image velocimetry (MicroPIV) measurements reveal the internal flow dynamics. Confocal imaging of fluorescently labelled PA elucidates the bacterial distribution within the deposits. FindingsThe study finds that the evaporation rate is drastically impeded during drying at elevated solutal concentrations, particularly at high RH and low temperature conditions. MicroPIV shows reduced internal flow under high RH and low temperature (low evaporation rate) conditions. Evaporation rate influences crystal growth, with delayed efflorescence and extending crystallization times. PA forms denser peripheral arrangements under high evaporation rates and shows a fivefold increase in survivability under low evaporation rates. These findings highlight the critical impact of environmental conditions on pathogen persistence and disease spread from inanimate surfaces.

New Insights into Pseudomonas spp.-Produced Antibiotics: Genetic Regulation of Biosynthesis and Implementation in Biotechnology.

Pseudomonas bacteria are renowned for their remarkable capacity to synthesize antibiotics, namely mupirocin, gluconic acid, pyrrolnitrin, and 2,4-diacetylphloroglucinol (DAPG). While these substances are extensively employed in agricultural biotechnology to safeguard plants against harmful bacteria and fungi, their potential for human medicine and healthcare remains highly promising for common science. However, the challenge of obtaining stable producers that yield higher quantities of these antibiotics continues to be a pertinent concern in modern biotechnology. Although the interest in antibiotics of Pseudomonas bacteria has persisted over the past century, many uncertainties still surround the regulation of the biosynthetic pathways of these compounds. Thus, the present review comprehensively studies the genetic organization and regulation of the biosynthesis of these antibiotics and provides a comprehensive summary of the genetic organization of antibiotic biosynthesis pathways in pseudomonas strains, appealing to both molecular biologists and biotechnologists. In addition, attention is also paid to the application of antibiotics in plant protection.

The potency of yellow pigment extract from the marine bacterium Pseudomonas oryzihabitans SAB E-3 as an antioxidant agent

Abstract. Putri DA, Astuti RI, Wahyudi AT. 2024. The potency of yellow pigment extract from the marine bacterium Pseudomonas oryzihabitans SAB E-3 as an antioxidant agent. Biodiversitas 25: 2565-2575. Metabolic processes in cells can produce byproducts in the form of Reactive Oxygen Species (ROS). Excessive amounts of ROS are one of the causes of oxidative stress. Antioxidants are known to act as free radical-scavenging compounds. Pigment-producing bacteria associated with sponges have been widely reported to have antioxidant compounds. In this study, the marine bacterium Pseudomonas oryzihabitans SAB E-3 produced intracellular yellow pigments with potential antioxidant activity. Therefore, this study aimed to assess the in vitro antioxidant and mitochondrial activity at the cellular level and identify chemical compounds. The intracellular pigments produced by P. oryzihabitans SAB E-3 were extracted using methanol, acetone, chloroform, and ethyl acetate. The methanol pigment extract contained the highest number of phenolic and flavonoid compounds, which may have contributed to its antioxidant activity. Furthermore, the active fraction obtained from the bioautographic TLC and harvested using preparative TLC had stronger antioxidant activity against DPPH radicals (75.71 µg/mL) than the crude pigment extract. However, the ABTS radical-reducing activity was lower (226.59 µg/mL) than the crude pigment extract. The maximum wavelength of the pigment extract was 453 nm, indicating the presence of carotenoids. In addition, the lowest concentration of the crude pigment extract (50 µg/mL) and selected active fractions (18.75 µg/mL) increased yeast Schizosaccharomyces pombe ARC039 tolerance to oxidative stress and induced mitochondrial activity. Active fraction one extract analyzed using LC-MS/MS contained piceatannol, resveratrol, isorhapontigenin, isoliquiritigenin, liquiritin, and 2-Omethylisohemigossylic acid lactone, which may contribute to its antioxidant activity. Therefore, the yellow pigment extract and the active fraction produced by P. oryzihabitans SAB E-3 are potential candidates for natural antioxidant sources.

Characteristics of Psychrotolerant Bacteria Isolated from Clay Organogenic Deposits of Mramorny Cave (Primorsky Territory)

A cultivated community of bacteria of the genus Pseudomonas was researched in clayey organogenic deposits of the Mramorny Cave (Primorsky Territory). The bacterial strains studied in this work are eurythermal and psychrotolerant. Their phylogenetic affiliation was found by high throughput sequencing of 16S rRNA gene fragments. It is known that bacteria of the genus Pseudomonas represent all the Earth ecological niches and, accordingly, have a wide range of adaptive functions. Using microscopy methods, a change in the nature of mobility and the cell size stability with changes in the temperatures of cultivating bacteria were established. The studied strains are of scientific and practical interest due to the enzymatic activity detection to several substrates simultaneously at different temperatures (25 and 4℃), as well as the ability to secrete cold active pectinase, protease and lipase. However, phosphate-solubilizing activity both at 4 and at 25℃ became preferable for the strains. The Mramorny Cave is karst and is characterized by carbonate karst, which explains the preference for the studied strains in calcium phosphate. An analysis of the obtained data shows that the collection of cultivated bacteria obtained by us includes both typical psychrotolerant ones, which exhibit enzymatic activity under conditions of optimal growth temperature, and unique ones, capable of synthesizing a wide range of enzymes under conditions not characteristic of its optimum growth.

Varietal Susceptibility of Olive to Pseudomonas savastanoi pv. savastanoi and the Antibacterial Potential of Plant-Based Agents.

Olive knot disease, caused by the bacterium Pseudomonas savastanoi pv. savastanoi, causes great damage in olive orchards. While control measures of P. savastanoi pv. savastanoi in olive orchards primarily rely on pruning and copper-based treatments, the use of antibiotics as bactericidal preparations in agriculture is limited and highly restricted. However, plants are naturally endowed with protective molecules, such as phenolic compounds, which defend them against herbivores, insects, and microorganisms. This research aimed to test the virulence of five strains of P. savastanoi pv. savastanoi isolated from different growing regions and olive varieties, and to examine whether there is a difference in plant susceptibility based on the variety. An additional goal was to test the antimicrobial activity of olive mill wastewater, known for its high content of phenolic compounds, and aqueous garlic hydrolysate, as well as to compare them with a commercial copper-based product, pure hydroxytyrosol, and a standard antibiotic as references. Analysis of knot characteristics showed variations in the virulence of the P. savastanoi pv. savastanoi strains, with the highest virulence being observed for the strain I7L and the lowest virulence for the strain B45C-PR. The olive cultivar Rosinjola displayed higher susceptibility compared to Frantoio, Buža, and Leccino, while cv. Istarska bjelica exhibited the least susceptibility compared to the other investigated olive cultivars. In an attempt to explore alternative solutions for disease control, in vitro tests revealed that the phenol HTyr, GE, and the wastewater with the highest total phenolic content (cv. Istarska bjelica) possess the highest antibacterial activity. This supports the role of polyphenols in host defense, aligning with previous field observations of lower susceptibility of cv. Istarska bjelica to olive knot disease. These findings highlight the complex nature of olive knot interactions with bacterial strains and olive cultivars, simultaneously accentuating and underscoring the importance of considering the host's defenses as well as bacterial virulence in disease management strategies.

Effect of Specific Spoilage Organisms on the Degradation of ATP-Related Compounds in Vacuum-Packed Refrigerated Large Yellow Croaker (Larimichthys crocea).

This study examined the spoilage potential of specific spoilage organisms on the degradation of adenosine triphosphate (ATP)-related compounds in vacuum-packed refrigerated large yellow croaker. The total viable count (TVC), ATP-related compounds and related enzymes of vacuum-packed refrigerated large yellow croaker inoculated with different bacteria (Pseudomonas fluorescens and Shewanella putrefaciens) were characterized using the spread plate method, high-performance liquid chromatography and assay kits, respectively. Results indicated that the TVC for both control and Shewanella putrefaciens groups reached spoilage levels at days 9 and 15, respectively. The changes of adenosine triphosphate (ATP), adenosine diphosphate (ADP), adenosine monophosphate (AMP) and adenosine deaminase activity across all groups showed no significant difference attributable to microbial growth. The results suggested that ATP to inosine monophosphate (IMP) degradation primarily occurs via fish's endogenous enzymes, with minimal microbial involvement. On day 12, the IMP content in fillets inoculated with Pseudomonas fluorescens (0.93 μmol/g) was half higher than in those inoculated with Shewanella putrefaciens (0.57 μmol/g). Both spoilage organisms facilitated IMP degradation, with Shewanella putrefaciens making a more substantial contribution. Analysis of K values and correlation coefficients revealed that Shewanella putrefaciens was the primary factor in the freshness loss of refrigerated vacuum-packed large yellow croaker. These findings offer a reference for understanding quality changes in refrigerated large yellow croaker, especially regarding umami degradation at the microbial level.

Molecular and functional characterization of ILYS-5, a major invertebrate lysozyme of Caenorhabditis elegans

To overcome bacterial invasion and infection, animals have evolved various antimicrobial effectors such as antimicrobial peptides and lysozymes. Although C. elegans is exposed to a variety of microbes due to its bacterivorous lifestyle, previous work on the components of its immune system mainly based on the description of transcriptional changes during bacterial challenges. Very few effector components of its immune system have been characterized so far. To investigate the role of lysozymes in terms of antibacterial defense and digestion, we studied a member of the widely neglected family of C. elegans invertebrate lysozymes (ILYS). We focused on the so far virtually undescribed ILYS-5, which we purified from protein extracts of C. elegans tracing its peptidoglycan-degrading activity and localized the tissue expression of the gene in vivo using a translational reporter construct. We recombinantly synthesized ILYS-5 and determined the physicochemical activity optimum and the antibacterial spectrum of a lysozyme from C. elegans for the first time. With an activity optimum at low ionic strength (≤100 mM) and at acidic pH (≤ pH 4.0), ILYS-5 is likely to be involved in killing and digestion of bacteria within acidified phagolysosomes and acidic regions of the gut, presumably secreted by lysosome-like vesicles. This notion is supported by potent activity against various live Gram-positive and Gram-negative bacteria. Notably, members of the natural associated microbiome of C. elegans are substantially less susceptible to ILYS-5. Ablation of the ilys-5 gene resulted in reduction of lifespan and fertility when cultured on the standard food bacterium Escherichia coli OP50, whereas exposure of the ilys-5 knock-out mutant to the host-associated bacterium Pseudomonas lurida MYb11 did not have a clear effect. These findings indicate a role of ILYS-5 in immunity and nutrition and a co-evolved adaptation of host and bacteria to the mutualistic nature of their interaction.

Potato Growth Promotion Using an Ecological Phosphate Fertiliser Composed of the Phosphate-Solubilising Bacterium Pseudomonas rhizophila S211 and Natural Rock Phosphate

Potato Growth Promotion Using an Ecological Phosphate Fertiliser Composed of the Phosphate-Solubilising Bacterium Pseudomonas rhizophila S211 and Natural Rock Phosphate