Cyanobacterial and microalgal bioactive compounds – the role of secondary metabolites in allelopathic interactions

2016 ◽  
Vol 45 (1) ◽  
Author(s):  
Adam Żak ◽  
Alicja Kosakowska
Keyword(s):  
Secondary Metabolites ◽  
Current Knowledge ◽  
Inhibitory Effect ◽  
Aquatic Environments ◽  
Practical Application ◽  
Ecological Importance ◽  
Bacteria And Fungi ◽  
Allelopathic Interactions ◽  
Allelopathic Compounds

AbstractSecondary metabolites produced by plants, algae, bacteria and fungi may affect the growth and development of biological systems. This is a natural process which occurs worldwide and is known as allelopathy. A relatively small number of these allelopathic compounds has been identified. The majority of studies describe the inhibitory effect of investigated compounds, extracts, cell-free filtrates and living cells on other organisms, although stimulatory interactions have also been noticed. Allelopathic interactions in aquatic environments could provide a competitive advantage to some species over other primary producers. Furthermore, allelopathy occurs in all aquatic habitats and all groups of autotrophs are capable of producing and releasing allelopathically active compounds. Moreover, secondary metabolites obtained from phytoplankton could demonstrate other useful bioactive properties. This review is intended to summarize the current knowledge of allelopathic interactions between microalgae and cyanobacteria in aquatic environments, as well as to provide a brief overview of the ecological importance of these interactions and their potential practical application in different branches of industry.

scholarly journals The Role of Gulls as Reservoirs of Antibiotic Resistance in Aquatic Environments: A Scoping Review

2021 ◽  
Vol 12 ◽  
Author(s):  
Danae Zeballos-Gross ◽  
Zulma Rojas-Sereno ◽  
Marília Salgado-Caxito ◽  
Patricia Poeta ◽  
Carmen Torres ◽  
...  
Keyword(s):  
Current Knowledge ◽  
Anthropogenic Sources ◽  
Future Research ◽  
Resistant Bacteria ◽  
Aquatic Environments ◽  
Antibiotic Resistant ◽  
Domestic Species ◽  
Sampling Protocols ◽  
Longitudinal Sampling

The role of wildlife with long-range dispersal such as gulls in the global dissemination of antimicrobial resistance (AMR) across natural and anthropogenic aquatic environments remains poorly understood. Antibiotic-resistant bacteria have been detected in resident and migratory gulls worldwide for more than a decade, suggesting gulls as either sentinels of AMR pollution from anthropogenic sources or independent reservoirs that could maintain and disperse AMR across aquatic environments. However, confirming either of these roles remains challenging and incomplete. In this review, we present current knowledge on the geographic regions where AMR has been detected in gulls, the molecular characterization of resistance genes, and the evidence supporting the capacity of gulls to disperse AMR across regions or countries. We identify several limitations of current research to assess the role of gulls in the spread of AMR including most studies not identifying the source of AMR, few studies comparing bacteria isolated in gulls with other wild or domestic species, and almost no study performing longitudinal sampling over a large period of time to assess the maintenance and dispersion of AMR by gulls within and across regions. We suggest future research required to confirm the role of gulls in the global dispersion of AMR including the standardization of sampling protocols, longitudinal sampling using advanced satellite tracking, and whole-genome sequencing typing. Finally, we discuss the public health implications of the spread of AMR by gulls and potential solutions to limit its spread in aquatic environments.

scholarly journals Allelopathic Interactions between Seeds of Portulaca oleracea L. and Various Crop Species

2021 ◽  
Vol 11 (8) ◽  
pp. 3539
Author(s):  
Sakineh Rashidi ◽  
Ali Reza Yousefi ◽  
Nieves Goicoechea ◽  
Majid Pouryousef ◽  
Parviz Moradi ◽  
...  
Keyword(s):  
Growth Parameters ◽  
Inhibitory Effect ◽  
Portulaca Oleracea ◽  
Crop Species ◽  
Screening Programs ◽  
Root And Shoot Length ◽  
Allium Cepa L ◽  
Negative Effect ◽  
Allelopathic Interactions

Allelopathy is described as the interference to plant growth resulting from chemical interactions among plants and other organisms mediated through the release of bioactive secondary metabolites. Since only a few studies have been reported about the role of seed allelopathy, an experiment was designed to evaluate the interactions among seeds of Portulaca oleracea L. and the crop species common bean (Phaseolus vulgaris L.), onion (Allium cepa L.), sugar beet (Beta vulgaris L.), broad bean (Vicia faba L.), and pea (Pisum sativum L.) on seed and seedling growth parameters. The results indicated that P. oleracea seeds had a negative effect on the germination of P. vulgaris and A. cepa. Conversely, germination of P. oleracea in the presence of P. vulgaris, A. cepa, and B. vulgaris seeds was strongly reduced with a higher inhibitory effect found for the seeds of A. cepa. The highest negative effect on root and shoot length was observed in P. vulgaris. Seedling vigor of all crop species decreased in the presence of P. oleracea. Our results suggest that seeds of P. vulgaris, A. cepa, and B. vulgaris exhibited high allelopathic effects against seeds of P. oleracea and can be used as potential bio-herbicides in future screening programs.

THE ROLE OF FISH AS CONVEYORS OF MICROORGANISMS IN AQUATIC ENVIRONMENTS

1961 ◽  
Vol 7 (4) ◽  
pp. 595-605 ◽  
Author(s):  
Louise F. Potter ◽  
Gladys E. Baker
Keyword(s):  
Aquatic Environments ◽  
Additional Species ◽  
Gram Negative ◽  
Microbial Distribution ◽  
Surface Samples ◽  
Flathead Lake ◽  
Bottom Mud ◽  
Microbial Analysis ◽  
Bacteria And Fungi

Microbial analysis of 60 fish caught in three areas of Flathead Lake, Montana, substantiated the theory that fish carry a significant population of bacteria and fungi on their body surfaces and in their digestive tracts. Bacterial counts often were in the hundred thousands per square centimeter. Numbers and kinds of bacteria varied from fish to fish, showing no relation to location or kind of fish. Gram-negative, chromogenic rods were found most frequently. The ease with which these organisms were removed indicates that fish are important as passive carriers of bacteria in the aquatic environment.There was no evidence that the fungi isolated were commensal with the fish or parasitic on them. Since all the fungus species isolated except one have been found in water or bottom mud of Flathead Lake, it would appear that fish operate also as passive conveyors of fungi. The idea that fish play a major role in microbial distribution is given substance by the fact that 48 species of fungi have been isolated from surface samples and 8 additional species from the contents of stomach and oesophagus.

scholarly journals Biofilms: hot spots of horizontal gene transfer (HGT) in aquatic environments, with a focus on a new HGT mechanism

2020 ◽  
Vol 96 (5) ◽  
Author(s):  
Kimihiro Abe ◽  
Nobuhiko Nomura ◽  
Satoru Suzuki
Keyword(s):  
Antibiotic Resistance ◽  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Hot Spots ◽  
Bacterial Communities ◽  
Current Knowledge ◽  
Antibiotic Resistance Genes ◽  
Membrane Vesicles ◽  
Aquatic Environments

ABSTRACT Biofilms in water environments are thought to be hot spots for horizontal gene transfer (HGT) of antibiotic resistance genes (ARGs). ARGs can be spread via HGT, though mechanisms are known and have been shown to depend on the environment, bacterial communities and mobile genetic elements. Classically, HGT mechanisms include conjugation, transformation and transduction; more recently, membrane vesicles (MVs) have been reported as DNA reservoirs implicated in interspecies HGT. Here, we review the current knowledge on the HGT mechanisms with a focus on the role of MVs and the methodological innovations in the HGT research.

scholarly journals Role of the phosphopantetheinyltransferase enzyme, PswP, in the biosynthesis of antimicrobial secondary metabolites by Serratia marcescens Db10

Microbiology ◽  
2014 ◽  
Vol 160 (8) ◽  
pp. 1609-1617 ◽  
Author(s):  
Amy J. Gerc ◽  
Nicola R. Stanley-Wall ◽  
Sarah J. Coulthurst
Keyword(s):  
Secondary Metabolites ◽  
Serratia Marcescens ◽  
Protein Domain ◽  
Carrier Protein ◽  
Negative Bacterium ◽  
Peptide Synthetases ◽  
Primary And Secondary Metabolism ◽  
Fatty Acid Synthases ◽  
Bacteria And Fungi

Phosphopantetheinyltransferase (PPTase) enzymes fulfil essential roles in primary and secondary metabolism in prokaryotes, archaea and eukaryotes. PPTase enzymes catalyse the essential modification of the carrier protein domain of fatty acid synthases, polyketide synthases (PKSs) and non-ribosomal peptide synthetases (NRPSs). In bacteria and fungi, NRPS and PKS enzymes are often responsible for the biosynthesis of secondary metabolites with clinically relevant properties; these secondary metabolites include a variety of antimicrobial peptides. We have previously shown that in the Gram-negative bacterium Serratia marcescens Db10, the PPTase enzyme PswP is essential for the biosynthesis of an NRPS-PKS dependent antibiotic called althiomycin. In this work we utilize bioinformatic analyses to classify PswP as belonging to the F/KES subfamily of Sfp type PPTases and to putatively identify additional NRPS substrates of PswP, in addition to the althiomycin NRPS-PKS, in Ser . marcescens Db10. We show that PswP is required for the production of three diffusible metabolites by this organism, each possessing antimicrobial activity against Staphylococcus aureus. Genetic analyses identify the three metabolites as althiomycin, serrawettin W2 and an as-yet-uncharacterized siderophore, which may be related to enterobactin. Our results highlight the use of an individual PPTase enzyme in multiple biosynthetic pathways, each contributing to the ability of Ser. marcescens to inhibit competitor bacteria by the production of antimicrobial secondary metabolites.

Bacillus subtilis – Arabidopsis thaliana: a model interaction system for studying the role of volatile organic compounds in the interchange between plants and bacteria

Botany ◽  
2019 ◽  
Vol 97 (12) ◽  
pp. 661-669
Author(s):  
Fei Li ◽  
Min Tang ◽  
Xiaoxin Tang ◽  
Wei Sun ◽  
Jiyi Gong ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Bacillus Subtilis ◽  
Molecular Mechanisms ◽  
Current Knowledge ◽  
Model System ◽  
Model Systems ◽  
Model Interaction ◽  
Volatile Organic ◽  
Ecological Importance

Plant–bacteria interactions are known to play important physiological roles in plant growth. Determining the mechanisms behind these interactions has paramount agricultural and ecological importance. Therefore, it is essential to study Plant–bacteria interactions and determine the relevant molecular mechanisms by using model systems. This review summarizes the current knowledge regarding plant–bacteria interactions based on the Arabidopsis thaliana – Bacillus subtilis model system, and highlights future areas for research.

Mesophyll conductance: the leaf corridors for photosynthesis

2020 ◽  
Vol 48 (2) ◽  
pp. 429-439 ◽  
Author(s):  
Jorge Gago ◽  
Danilo M. Daloso ◽  
Marc Carriquí ◽  
Miquel Nadal ◽  
Melanie Morales ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Current Knowledge ◽  
Main Role ◽  
Mesophyll Conductance ◽  
Future Studies ◽  
Cell Structures ◽  
Leaf Tissues ◽  
Change Framework ◽  
Chloroplast Stroma

Besides stomata, the photosynthetic CO2 pathway also involves the transport of CO2 from the sub-stomatal air spaces inside to the carboxylation sites in the chloroplast stroma, where Rubisco is located. This pathway is far to be a simple and direct way, formed by series of consecutive barriers that the CO2 should cross to be finally assimilated in photosynthesis, known as the mesophyll conductance (gm). Therefore, the gm reflects the pathway through different air, water and biophysical barriers within the leaf tissues and cell structures. Currently, it is known that gm can impose the same level of limitation (or even higher depending of the conditions) to photosynthesis than the wider known stomata or biochemistry. In this mini-review, we are focused on each of the gm determinants to summarize the current knowledge on the mechanisms driving gm from anatomical to metabolic and biochemical perspectives. Special attention deserve the latest studies demonstrating the importance of the molecular mechanisms driving anatomical traits as cell wall and the chloroplast surface exposed to the mesophyll airspaces (Sc/S) that significantly constrain gm. However, even considering these recent discoveries, still is poorly understood the mechanisms about signaling pathways linking the environment a/biotic stressors with gm responses. Thus, considering the main role of gm as a major driver of the CO2 availability at the carboxylation sites, future studies into these aspects will help us to understand photosynthesis responses in a global change framework.

Prospective Memory Development Across the Lifespan

2020 ◽  
Vol 25 (3) ◽  
pp. 162-173 ◽  
Author(s):  
Sascha Zuber ◽  
Matthias Kliegel
Keyword(s):  
Prospective Memory ◽  
Healthy Aging ◽  
Present Model ◽  
Current Knowledge ◽  
Well Being ◽  
The Elderly ◽  
Cognitive Factors ◽  
Everyday Functioning ◽  
Integrative Framework

Abstract. Prospective Memory (PM; i.e., the ability to remember to perform planned tasks) represents a key proxy of healthy aging, as it relates to older adults’ everyday functioning, autonomy, and personal well-being. The current review illustrates how PM performance develops across the lifespan and how multiple cognitive and non-cognitive factors influence this trajectory. Further, a new, integrative framework is presented, detailing how those processes interplay in retrieving and executing delayed intentions. Specifically, while most previous models have focused on memory processes, the present model focuses on the role of executive functioning in PM and its development across the lifespan. Finally, a practical outlook is presented, suggesting how the current knowledge can be applied in geriatrics and geropsychology to promote healthy aging by maintaining prospective abilities in the elderly.

Effect of Dipyridamole on Spontaneous Platelet Aggregation in Whole Blood Decreases with the Time After Venepuncture: Evidence for the Role of ADP

1987 ◽  
Vol 58 (02) ◽  
pp. 744-748 ◽  
Author(s):  
A R Saniabadi ◽  
G D O Lowe ◽  
J C Barbenel ◽  
C D Forbes
Keyword(s):  
Platelet Aggregation ◽  
Correlation Coefficient ◽  
Whole Blood ◽  
Blood Platelet ◽  
Inhibitory Effect ◽  
Time Interval ◽  
Adp Receptor ◽  
Spontaneous Platelet Aggregation

SummarySpontaneous platelet aggregation (SPA) was studied in human whole blood at 3, 5, 10, 20, 30, 40 and 60 minutes after venepuncture. Using a whole blood platelet counter, SPA was quantified by measuring the fall in single platelet count upon rollermixing aliquots of citrated blood at 37° C. The extent of SPA increased with the time after venepuncture, with a correlation coefficient of 0.819. The inhibitory effect of dipyridamole (Dipy) on SPA was studied: (a) 10 μM at each time interval; (b) 0.5-100 μM at 3 and 30 minutes and (c) 15 μM in combination with 100 μM adenosine, 8 μM 2-chloroadenosine (2ClAd, an ADP receptor blocker) and 50 μM aspirin. There was a rapid decrease in the inhibitory effect of Dipy with the time after venepuncture; the correlation coefficient was -0.533. At all the concentrations studied, Dipy was more effective at 3 minutes than at 30 minutes after venepuncture. A combination of Dipy with adenosine, 2ClAd or aspirin was a more effective inhibitor of SPA than either drug alone. However, when 15 μM Dipy and 10 μM Ad were added together, the inhibitory effect of Dipy was not increased significantly, suggesting that Dipy inhibits platelet aggregation independent of Ad. The increase in SPA with the time after venepuncture was abolished when blood was taken directly into the anticoagulant containing 5 μM 2ClAd. It is suggested that ADP released from the red blood cells is responsible for the increased platelet aggregability with the time after venepuncture and makes a serious contribution to the artifacts of in vitro platelet function studies.

Effect of human galanin on the response of circulating catecholamines to hypoglycemia in man

1995 ◽  
Vol 133 (6) ◽  
pp. 723-728 ◽  
Author(s):  
Ettore C degli Uberti ◽  
Maria R Ambrosio ◽  
Marta Bondanelli ◽  
Giorgio Transforini ◽  
Alberto Valentini ◽  
...  
Keyword(s):  
Heart Rate ◽  
Healthy Subjects ◽  
Sympathetic Nerve Activity ◽  
Heart Rate Response ◽  
Statistical Significance ◽  
Inhibitory Effect ◽  
Amino Acid Residues ◽  
Nerve Activity ◽  
Receptor Stimulation

degli Uberti EC, Ambrosio MR, Bondanelli M, Trasforini G, Valentini A, Rossi R, Margutti A, Campo M. Effect of human galanin on the response of circulating catecholamines to hypoglycemia in man. Eur J Endocrinol 1995;133:723–8. ISSN 0804–4643 Human galanin (hGAL) is a neuropeptide with 30 amino acid residues that has been found in the peripheral and central nervous system, where it often co-exists with catecholamines. In order to clarify the possible role of hGAL in the regulation of sympathoadrenomedullary function, the effect of a 60 min infusion of hGAL (80 pmol·kg−1 · min−1) on plasma epinephrine and norepinephrine responses to insulin-induced hypoglycemia in nine healthy subjects was investigated. Human GAL administration significantly reduced both the release of basal norepinephrine and the response to insulin-induced hypoglycemia, whereas it attenuated the epinephrine response by 26%, with the hGAL-induced decrease in epinephrine release failing to achieve statistical significance. Human GAL significantly increased the heart rate in resting conditions and clearly exaggerated the heart rate response to insulin-induced hypoglycemia, whereas it had no effect on the blood pressure. We conclude that GAL receptor stimulation exerts an inhibitory effect on basal and insulin-induced hypoglycemia-stimulated release of norepinephrine. These findings provide further evidence that GAL may modulate sympathetic nerve activity in man but that it does not play an important role in the regulation of adrenal medullary function. Ettore C degli Uberti, Chair of Endocrinology, University of Ferrara, Via Savonarola 9, I-44100 Ferrara, Italy

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