scholarly journals Effects of Gelling Agent and Extracellular Signaling Molecules on the Culturability of Marine Bacteria

2017 ◽  
Vol 83 (9) ◽  
Author(s):  
Anita Mac Rygaard ◽  
Mariane Schmidt Thøgersen ◽  
Kristian Fog Nielsen ◽  
Lone Gram ◽  
Mikkel Bentzon-Tilia
Keyword(s):  
Marine Bacteria ◽  
Incubation Temperature ◽  
Amplicon Sequencing ◽  
Signaling Molecules ◽  
Medium Composition ◽  
Gellan Gum ◽  
Gelling Agent ◽  
Marine Microorganisms ◽  
Medium Components ◽  
Cell Counts

ABSTRACT Only 1% of marine bacteria are currently culturable using standard laboratory procedures, and this is a major obstacle for our understanding of the biology of marine microorganisms and for the discovery of novel microbial natural products. Therefore, the purpose of this study was to investigate if improved cultivation conditions, including the use of an alternative gelling agent and supplementation with signaling molecules, improve the culturability of bacteria from seawater. Replacing agar with gellan gum improved viable counts 3- to 40-fold, depending on medium composition and incubation conditions, with a maximum of 6.6% culturability relative to direct cell counts. Through V4 amplicon sequencing we found that culturable diversity was also affected by a change in gelling agent, facilitating the growth of orders not culturable on agar-based substrates. Community analyses showed that communities grown on gellan gum substrates were significantly different from communities grown on agar and that they covered a larger fraction of the seawater community. Other factors, such as incubation temperature and time, had less obvious effects on viable counts and culturable diversity. Supplementation with acylated homoserine lactones (AHLs) did not have a positive effect on total viable counts or a strong effect on culturable diversity. However, low concentrations of AHLs increased the relative abundance of sphingobacteria. Hence, with alternative growth substrates, it is possible to significantly increase the number and diversity of cultured marine bacteria. IMPORTANCE Serious challenges to human health, such as the occurrence and spread of antibiotic resistance and an aging human population in need of bioactive pharmaceuticals, have revitalized the search for natural microbial products. The marine environment, representing the largest ecosystem in the biosphere, harbors an immense and virtually untapped microbial diversity producing unique bioactive compounds. However, we are currently able to cultivate only a minute fraction of this diversity. The lack of cultivated microbes is hampering not only bioprospecting efforts but also our general understanding of marine microbes. In this study, we present a means to increase the number and diversity of cultured bacteria from seawater, showing that relatively simple changes to medium components may facilitate the isolation and growth of hitherto unknown bacterial orders.

A medium, solidified with gellan gum, for determining the Na+ requirement of Vibrio species

1993 ◽  
Vol 39 (8) ◽  
pp. 804-808 ◽  
Author(s):  
Lisa D. Noble ◽  
John A. Gow
Keyword(s):  
Marine Bacteria ◽  
Solid Medium ◽  
Specific Growth ◽  
Basal Medium ◽  
Gellan Gum ◽  
Growth Responses ◽  
Prolonged Incubation ◽  
Low Sodium ◽  
Growth Requirements ◽  
Lag Period

Until now there has not been a satisfactory solid medium for determining the growth responses, to Na+, of marine and other bacteria that have specific growth requirements for Na+. A solid medium would be useful to investigators who would like to take advantage of the efficiency of multipoint inoculation when testing for a Na+ requirement. By using 1% gellan gum (Gel-GroTM) as the solidifying agent a medium was formulated that had a contaminating level of Na+ of slightly less than 2 mM in the basal medium. Two species of Aeromonas, which do not require Na+ for growth, and 31 species of Vibrio, which require Na+, were tested for their growth responses to Na+ on this medium. The Aeromonas strains grew well, within 24 h, at all of the Na+ concentrations tested. Approximately 75% of the Vibrio strains did not grow on the basal medium even after a prolonged incubation period. The remaining species were able to grow on the basal medium, but not without a lag period. These lag periods were as short as 36 h for two of the species and in some instances as long as 312 h. These lag periods were of sufficient duration to determine that Na+ stimulated the growth of the Vibrio strains that were able to grow on the basal medium. Approximately 75% of the strains, representing most species of Vibrio, were able to grow if as little as 25 mM Na+ was present in the medium.Key words: low-sodium medium, Na+ requirement, gellan gum, agar substitute, marine bacteria.

Evaluation of the Petrifilm Aerobic Count Plate for Enumeration of Aerobic Marine Bacteria from Seawater and Caulerpa lentillifera

2010 ◽  
Vol 73 (8) ◽  
pp. 1529-1532 ◽  
Author(s):  
JUN KUDAKA ◽  
TORU HORII ◽  
KOJI TAMANAHA ◽  
KIYOMASA ITOKAZU ◽  
MASAJI NAKAMURA ◽  
...  
Keyword(s):  
Marine Bacteria ◽  
Close Correlation ◽  
Marine Microorganisms ◽  
Marine Agar ◽  
Suitable Alternative ◽  
Edible Seaweed ◽  
Sterile Seawater ◽  
Caulerpa Lentillifera ◽  
Simple Detection ◽  
Aerobic Count Plate

The enumeration and evaluation of the activity of marine bacteria are important in the food industry. However, detection of marine bacteria in seawater or seafood has not been easy. The Petrifilm aerobic count plate (ACP) is a ready-to-use alternative to the traditional enumeration media used for bacteria associated with food. The purpose of this study was to evaluate the usefulness of a simple detection and enumeration method utilizing the Petrifilm ACP for enumeration of aerobic marine bacteria from seawater and an edible seaweed, Caulerpa lentillifera. The efficiency of enumeration of total aerobic marine bacteria on Petrifilm ACP was compared with that using the spread plate method on marine agar with 80 seawater and 64 C. lentillifera samples. With sterile seawater as the diluent, a close correlation was observed between the method utilizing Petrifilm ACP and that utilizing the conventional marine agar (r = 0.98 for seawater and 0.91 for C. lentillifera). The Petrifilm ACP method was simpler and less time-consuming than the conventional method. These results indicate that Petrifilm ACP is a suitable alternative to conventional marine agar for enumeration of marine microorganisms in seawater and C. lentillifera samples.

scholarly journals Use of Alternative Gelling Agents Reveals the Role of Rhamnolipids in Pseudomonas aeruginosa Surface Motility

Biomolecules ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1468
Author(s):  
Charles D. Morin ◽  
Eric Déziel
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Strong Dependence ◽  
Gellan Gum ◽  
Gelling Agent ◽  
Gelling Agents ◽  
Bacterial Surface ◽  
Solid Media ◽  
Surface Motility ◽  
Wetting Agents ◽  
The Impact

Pseudomonas aeruginosa is a motile bacterium able to exhibit a social surface behaviour known as swarming motility. Swarming requires the polar flagellum of P. aeruginosa as well as the secretion of wetting agents to ease the spread across the surface. However, our knowledge on swarming is limited to observed phenotypes on agar-solidified media. To study the surface behaviour and the impact of wetting agents of P. aeruginosa on other surfaces, we assessed surface motility capabilities of the prototypical strain PA14 on semi-solid media solidified with alternative gelling agents, gellan gum and carrageenan. We found that, on these alternative surfaces, the characteristic dendritic spreading pattern of P. aeruginosa is drastically altered. One striking feature is the loss of dependence on rhamnolipids to spread effectively on plates solidified with these alternative gelling agents. Indeed, a rhlA-null mutant unable to produce its wetting agents still spreads effectively, albeit in a circular shape on both the gellan gum- and carrageenan-based media. Our data indicate that rhamnolipids do not have such a crucial role in achieving surface colonization of non-agar plates, suggesting a strong dependence on the physical properties of the tested surface. The use of alternative gelling agent provides new means to reveal unknown features of bacterial surface behaviour.

scholarly journals Effect of Gellan Gum and Xanthan Gum Synergistic Interactions and Plasticizers on Physical Properties of Plant-Based Enteric Polymer Films

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 121 ◽  
Author(s):  
Na Zhang ◽  
Xiaohui Li ◽  
Jing Ye ◽  
Yucheng Yang ◽  
Yayan Huang ◽  
...  
Keyword(s):  
Water Vapor ◽  
Polymer Films ◽  
Xanthan Gum ◽  
Tensile Elongation ◽  
Gellan Gum ◽  
Gelling Agent ◽  
Mixed System ◽  
Synergistic Interactions ◽  
Peg 400 ◽  
Enteric Polymer

The mechanical and barrier properties of plant-based enteric polymer films were enhanced by synergistic interactions between binary gum mixtures and adding plasticizers. The results indicated that the best ratio of gellan gum (GG) and xanthan gum (XG) was 7:3 by comparing tensile strength, tensile elongation, transmittance, and water vapor permeability of plant-based enteric polymer films and rheological properties of solutions. Polyethylene glycol 400 (PEG-400) was an effective plasticizer in improving plasticity and water vapor barrier property of the plant-based enteric polymer film. Rheology measurement and different characterization methods, including Fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, X-ray diffraction, and scanning electron microscopy, were used to explain interactions between GG and XG as well as PEG-400 and components of the film. The new mixed system, composed of GG/XG mixture with ratio of 7:3 as a novel gelling agent and PEG-400 as a plasticizer, was applied to prepare plant-based enteric hard capsules, which have potential applications in medicines and functional food preparations.

scholarly journals Influence of Culture Conditions and Medium Composition on the Production of Cellulose by Shiga Toxin-Producing Escherichia coli Cells

2009 ◽  
Vol 75 (13) ◽  
pp. 4630-4632 ◽  
Author(s):  
Byong Kwon Yoo ◽  
Jinru Chen
Keyword(s):  
Escherichia Coli ◽  
Water Activity ◽  
Shiga Toxin ◽  
Incubation Temperature ◽  
Culture Conditions ◽  
Luria Bertani ◽  
Medium Composition ◽  
Cellulose Production ◽  
Escherichia Coli Cells

ABSTRACT Culture conditions favoring cellulose production by Shiga toxin-producing Escherichia coli included a 28°C incubation temperature, an aerobic atmosphere, and the presence of 2% ethanol in Luria-Bertani no-salt agar with pH 6.0 and a water activity of 0.99. These findings will assist in formulating microbiological media useful for cellulose and biofilm research.

scholarly journals Novel Factors Affecting Shoot Culture of Chrysanthemum (Dendranthema × Grandiflora)

2014 ◽  
Vol 20 (1) ◽  
pp. 27-40 ◽  
Author(s):  
Jaime A. Teixeira Da Silva
Keyword(s):  
Tissue Culture ◽  
Corn Starch ◽  
Shoot Culture ◽  
Stevia Rebaudiana ◽  
Gellan Gum ◽  
Gelling Agent ◽  
Root Production ◽  
Dendranthema Grandiflora ◽  
Poor Growth ◽  
Factors Affecting

Abstract Teixeira da Silva J.A., 2014: Novel factors affecting shoot culture of chrysanthemum (Dendranthema × grandiflora) [Alternatyvių standiklių, skystų terpės priedų, CO2 sodrinimo ir kitų faktorių įtaka chrizantemų (Dendranthema × grandiflora (Ramat.) Kitamura) ūglių kultūrų auginimui]. - Bot. Lith., 20(1): 27-40. Chrysanthemum (Dendranthema × grandiflora (Ramat.) Kitamura) continues to be one of the most important ornamental plants in the world. Although the tissue culture of chrysanthemum has been widely explored, several unexplored topics remain, and, in developing countries, there is always the constant search for reducing the cost of raising tissue cultured plants. In this study, by focusing on a leading market cultivar in Japan, ‘Shuhouno- chikara’, alternatives to agar (as the gelling agent) and sucrose (as the carbon source) for chrysanthemum tissue culture were sought. Both Gellan gum and agar resulted in greater shoot and root production than all other gelling agents tested, including Bacto agar, phytagel, oatmeal agar, potato dextrose agar, barley starch and corn starch. All of the alternative liquid-based medium additives tested (low and full fat milk, Coca-cola ®, coffee, Japanese green, Oolong and Darjeeling teas) negatively impacted plant growth, stunted roots and decreased chlorophyll content (SPAD value) of leaves. There was no difference between plants grown on medium with refined sucrose or table sugar, although poor growth was observed when stevia (Stevia rebaudiana) extract was used. Photoautotrophic micropropagation increased significantly the shoot mass relative to control plants, even when the density of plants was doubled. Aeration improved plantlet growth. The tetrazolium test was a simple, but effective essay to see the intensity and strength of root growth in different basal media. MDH activity decreased in the root+shoot extract of plants grown on most alternative media, but remained high on TCSGM (Teixeira’s chrysanthemum shoot growth medium), Gellan gum, aerated and CO2-enriched cultures. A similar trend was observed for deaminating GDH, while an opposite trend was observed for aminating GDH activity. These experiments indicate that tissue culture research for chrysanthemum still provides a rich field for exploration with interesting and valuable results

Optimization of Medium Components for β-Glucosidase Production from Aspergillus Niger by Response Surface Methodology

2013 ◽  
Vol 419 ◽  
pp. 328-333 ◽  
Author(s):  
Chao Zhang ◽  
Rui Huang ◽  
Hui Tian ◽  
Ru Ming Zhao ◽  
Fa Shun Yu ◽  
...  
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Yeast Extract ◽  
Influence Factors ◽  
Mutual Effect ◽  
Tween 80 ◽  
Fermentation Medium ◽  
Medium Composition ◽  
Malt Extract ◽  
Medium Components

β-Glucosidase is the key enzyme for the utilization of lignocellulose.But the commercial β-glucosidase can’t be produced. This paper focuses on the study of the β-glucosidase fermentation process.The fermentation medium components for β-glucosidase production from Aspergil lusniger was optimized by response surface methodology (RSM). Firstly, the three of the most important influence factors yeast extract, MnSO4•H2O and MgSO4•7H2O was obtained from Plackett-Burman design screening. Then the path of steepest ascent experiment was adopted to approach the optimal region of the medium composition. Lastly, the optimal concentration and mutual effect of three factors were predicted by RSM. The results showed that the best medium composition was Malt extract 18g/L, Yeast extract 3.22g/L, KH2PO4 3g/L, MnSO4•H2O 0.58mM, Tween-80 0.5mL/L and MgSO4•7H2O 0.23g/L. Under these fermentation conditions, the activity of β-glucosidase was up to 7.33IU/mL with increasing 23.2% than before.

scholarly journals Research Progress in Anti-Inflammatory Bioactive Substances Derived from Marine Microorganisms, Sponges, Algae, and Corals

Marine Drugs ◽  
2021 ◽  
Vol 19 (10) ◽  
pp. 572
Author(s):  
Chao-Qun Li ◽  
Qin-Yuan Ma ◽  
Xiu-Zhen Gao ◽  
Xuan Wang ◽  
Bei-Li Zhang
Keyword(s):  
Marine Bacteria ◽  
Marine Organism ◽  
Research Progress ◽  
Defense Reaction ◽  
Marine Microorganisms ◽  
Bioactive Substances ◽  
Evaluation Models ◽  
Inflammatory Drugs ◽  
Anti Inflammatory ◽  
Bacteria And Fungi

Inflammation is the body’s defense reaction in response to stimulations and is the basis of various physiological and pathological processes. However, chronic inflammation is undesirable and closely related to the occurrence and development of diseases. The ocean gives birth to unique and diverse bioactive substances, which have gained special attention and been a focus for anti-inflammatory drug development. So far, numerous promising bioactive substances have been obtained from various marine organisms such as marine bacteria and fungi, sponges, algae, and coral. This review covers 71 bioactive substances described during 2015–2020, including the structures (65 of which), species sources, evaluation models and anti-inflammatory activities of these substances. This review aims to provide some reference for the research progress of marine-organism-derived anti-inflammatory metabolites and give more research impetus for their conversion to novel anti-inflammatory drugs.

scholarly journals Preparation, Characterization, and Wound Healing Activity of Papaya Leaves Extract on Spray Gel

2020 ◽  
Vol 25 (2) ◽  
pp. 103
Author(s):  
Dina Permata Wijaya ◽  
Herlina Herlina ◽  
Najma Annuria Fitri ◽  
Mardiyanto Mardiyanto ◽  
Mustikasanti Mustikasanti ◽  
...  
Keyword(s):  
Wound Healing ◽  
Positive Control ◽  
Negative Control ◽  
Gellan Gum ◽  
Gelling Agent ◽  
Carbopol 940 ◽  
Ph Range ◽  
Wound Healing Activity

Papaya leaves have been using for wound healing that contains flavonoids, saponins, phenolics, chymopapain, and papain enzymes. The aim of this research were preparation, characterization, and wound healing activity of papaya leaves extract on spray gel. Spray gel was formulated with variation of gelling agent such as carbopol 940, HPMC, gellan gum, and hydroxyethylcellulose. The spray gel were characterizated by organoleptic, pH, stickiness test, viscosity, homogeneity, weight, and wound healing activity in rats. The results showed were all of formula spray gel have brown and homogeneous, pH between 5,947-6,347 within pH range of skin, stickiness test between 1,92-8,12 s, viscosity between 880-1740 cPs. Papaya leaves extract on spray gel has wound healing activity in rats faster than extract and positive control that is 16 days. The wound healing of papaya leaves extract on spray gel exhibited significantly different (p<0,05) than negative control.

scholarly journals Isolation of SAR11 Marine Bacteria from Cryopreserved Seawater

mSystems ◽  
2020 ◽  
Vol 5 (6) ◽  
pp. e00954-20
Author(s):  
Elizabeth A. Monaghan ◽  
Kelle C. Freel ◽  
Michael S. Rappé
Keyword(s):  
High Throughput ◽  
Marine Bacteria ◽  
Mixed Cultures ◽  
Rrna Gene ◽  
Marine Microorganisms ◽  
Culture Collections ◽  
Natural Systems ◽  
Wide Range ◽  
Long Time ◽  
Cultivation Experiment

ABSTRACTWhile marine microorganisms are frequently studied in their natural environment, isolated strains are invaluable resources that can be used in controlled experiments to expand upon direct observations from natural systems. Here, we sought a means to enhance culture collections of SAR11 marine bacteria by testing the use of seawater cryopreserved with glycerol as an inoculum. Using a raw seawater sample collected from the tropical Pacific Ocean, a subsample was diluted in seawater growth medium to create 576 2-ml dilution cultures containing 5 cells each and incubated for a high-throughput culturing (HTC) experiment, while another portion was cryopreserved in 10% glycerol. After 10 months, a cryopreserved aliquot was thawed and used to create a second cultivation experiment of 480 2-ml cultures containing 5 cells each and 470 cultures containing 105 cells each. The raw seawater cultivation experiment resulted in the successful isolation of 54 monocultures and 29 mixed cultures, while cryopreserved seawater resulted in 59 monocultures and 29 mixed cultures. Combined, the cultures included 51 SAR11 isolates spanning 11 unique 16S rRNA gene amplicon sequence variants (ASVs) from the raw seawater inoculum and 74 SAR11 isolates spanning 13 unique ASVs from cryopreserved seawater. A vast majority (92%) of SAR11 isolates from the two HTC experiments were members of SAR11 subclade Ia, though subclades IIIa and Va were also recovered from cryopreserved seawater and subclade Ib was recovered from both. The four most abundant SAR11 subclade Ia ASVs found in the initial seawater environmental sample were isolated by both approaches.IMPORTANCE High-throughput dilution culture has proved to be a successful approach to bring some difficult-to-isolate planktonic microorganisms into culture, including the highly abundant SAR11 lineage of marine bacteria. While the long-term preservation of bacterial isolates by freezing them in the presence of cryoprotectants, such as glycerol, has been shown to be an effective method of storing viable cells over long time periods (i.e., years), to our knowledge it had not previously been tested for its efficacy in preserving raw seawater for later use as an inoculum for high-throughput cultivation experiments. We found that SAR11 and other abundant marine bacteria could be isolated from seawater that was previously cryopreserved for nearly 10 months at a rate of culturability similar to that of the same seawater used fresh, immediately after collection. Our findings (i) expand the potential of high-throughput cultivation experiments to include testing when immediate isolation experiments are impractical, (ii) allow for targeted isolation experiments from specific samples based on analyses such as microbial community structure, and (iii) enable cultivation experiments across a wide range of other conditions that would benefit from having source inocula available over extended periods of time.

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