Marine Ecosystems. Land fossils are about : 450 million years old. The oldest known marine fossils are about : 3:5 billion years

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2 Marine Ecosystems Land fossils are about : 450 million years old The oldest known marine fossils are about : 3:5 billion years More than different kinds of species are present in the marine environment More than 80% of living organisms on earth are found in the aquatic ecosystem.

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4 The oceans cover 70% of the earth s surface Marine environment offers a diversity of habitats which is reflected in the biological diversity that is found in marine organisms.

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6 Food and Agricultural Organization (FAO) Any technological application that uses biological systems, living organisms, or derivatives thereof, to make or modify products or processes for specific use. The application of scientific and engineering principles to the processing of materials by marine biological agents provide good and services

7 Examples of products and services developed by technological applications using marine bioresources

8 Important marine sources in the research are microorganisms, algae, and sponges It is notable that the major international effort involved 2700 researchers, about 44% from USA and Canada, 31% from Europe, 25% from the rest of the world, notably Australia, New Zealand, Japan, China, South Africa, India, Indonesia, and Brazil

9 Countries and their marine biotechnology research priorities

10 Total number of new compounds isolated from different types of marine sources,

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12 The largest structures made by living creatures They contain an enormous diversity of organisms,

13 The economic value of coral reefs has been estimated to be US$375 billion per year 2 (largely derived from fishing, tourism and coastal protection activities)

14 of two layers of cells, the epidermis and gastrodermis, covered by a surface mucus layer and connected to a large, porous calcium carbonate skeleton

15 Very simple body many materials previously isolated from macroorganisms, such as sponges and tunicates, are in fact, metabolic products of associated microorganisms

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17 The mucus layer, skeleton and tissues of healthy corals all contain large populations of: I. eukaryotic algae, II. bacteria III. and archaea. Corals mucus layer

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21 The role of microorganism in coral

22 The role of microorganism in coral These microorganisms confer benefits to their host by various mechanisms, including I. photosynthesis, II. nitrogen fixation, III. provision of nutrients IV. infection prevention.

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24 The apparent uniformity of the symbionts isolated from various hosts led to the assumption that all symbiotic dinoflagellates belonged to a single species Symbiodinium microadriaticum Molecular evidence has since demonstrated that the genus Symbiodinium is diverse, containing multiple taxa

25 Each coral has its own symbiotic micro-algae

26 The energy requirements of their hosts by transferring photosynthetically fixed carbon to the coral The production of large amounts of molecular oxygen that allows for efficient respiration by the coral The high concentration of oxygen results in formation of oxygen radicals which provide protection against infection A pathogen of Symbiodinium in the coral required SOD to initiate infection

27 Symbiodinium Produce Mycosporines and Mycosporine-like amino acids (MAAs) : low-molecular-weight water-soluble molecules absorbing UV radiation in the wavelength range nm Mycosporines localize to the coral mucus and are hypothesized to protect the holobiont against UV radiation and to serve as antioxidants

28 Symbiodinium and Microbial communities Coral microbial communities have been shown to differ based on the clade of Symbiodinium present in coral species Under both stressed and non-stressed conditions supporting the hypothesis that unknown factors associated with different Symbiodinium genotypes influence the coral microbiota composition.

29 Healthy and bleached corals can be modeled in the laboratory by studying the Symbiodinium symbiosis.

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32 Bacteria satisfy 50% of the total nitrogen needs of the coral Bacteria provide organic compounds (produced by photosynthesis) to the coral tissue Bacteria could be crucial for the survival of the coral when it loses its endosymbiotic algae

33 Surface mucus layer Coral tissue (including the gastrodermal cavity) Calcium carbonate skeleton, each of which harbour a distinct bacterial population

34 The coral bacterial community differs from seawater surrounding the coral the coral and its microbiota is specific suggesting the association between

35 The coral probiotic hypothesis The ability of coral to adapt to environmental stresses temperature conditions infection by specific pathogens A dynamic relationship exists between symbiotic microorganisms and corals at different environmental conditions

36 The transmission of symbionts in corals Vertical transmission transfer of symbionts from parent to offspring Horizontal transmission uptake of symbionts from the environment

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38 Microbial associations over evolutionary time scales are likely to contribute to genome differentiation in both the host and its associated microbial partners

39 Bacterial genome evolution in the holobiont Data on genome size reduction come from studies on insect endosymbiosis If a bacterial symbiont is both vertically transmitted and an endosymbiont, its genome will be more likely to be reduced in size relative to other bacterial that have free-living stages. Observation The coral-associated bacterial genomes are of a similar size as their non-coral associated relatives For example : coral-associated genomes from Proteobacteria is similar with free-living Proteobacteria

40 Environmental stress factors Climate change, water pollution over-fishing Stress resistance: the coral probiotic hypothesis corals contain an innate immunity system, they do not produce antibodies lack an adaptive immunity system

41 Innate immunity Like other invertebrates, corals possess innate or natural immunity include I. Physical barriers, such as the epidermis and mucus (the mucus surrounds the coral and is shed periodically removing trapped microorganisms II. Cellular components (phagocytic cells) that can engulf and destroy microorganisms on contact III. Soluble factors, including organic acids and antimicrobial products coral-associated bacteria inhibit pathogen invasion and actively

42 Evidence for metabolic complementation Oligotrophic habitat of corals Makes metabolic complementation desirable Association between diazotrophic bacteria and coral Nitrogen fixation For instance Coral Acropora digitifera lacked a key enzyme that synthesizes the essential amino acid cysteine from homocysteine or serine Cysteinethione β synthase (CBS) is missing also from two other Acropora species but it has been reported in many corals

43 How coral microbe interactions facilitate the coral life cycle Microbial interactions can play a role at each of the stages in a coral s life cycle Scleractinian corals reproduce I. asexually through budding and fragmentation II. sexually by gamete spawning

44 How coral microbe interactions facilitate the coral life cycle

45 How coral microbe interactions facilitate the coral life cycle (1) fertilization and spawning fertilization of gametes and formation of a motile pelagic planula larva Mucus layer surrounding the gametes of spawning corals as media for transfer of symbionts (Symbiodinium and bacterial species) from parent colony to larvae after gamete release

46 How coral microbe interactions facilitate the coral life cycle (1) fertilization and spawning Antimicrobial activity of resident microbes may serve a protective function for coral spawn or newly hatched larvae

47 How coral microbe interactions facilitate the coral life cycle (2) Settlement and metamorphosis the selection of appropriate settlement substrate by the free-swimming planula and metamorphosis into polyp Bacteria have a fundamental role in moderating metamorphosis and settlement of larvae in the marine environment This event may be triggered by diffusible or potentially contact-mediated signals Mechanism behind induction of coral metamorphosis by various Pseudoalteromonas strains led to isolation of the inducing Compound tetrabromopyrrole (TBP) Certain populations of bacteria may also deter coral settlement through diffusible signals larvae avoid settling adjacent to benthic cyanobacteria hypothesized to produce toxic secondary metabolites

48 Coral colony formation High mortality (up to 100%) of coral nubbins grown with algal competitors Coral must overcome competition with other benthic organisms to grow and form adult colony. Bacteria help coral colonies versus competitors such as macro- and turf algae Antibacterial compound ampicillin rather than algal toxins, mediated the inhibitory effects

49 Coral colony formation organic carbon by primary producers may enrich for heterotrophic bacteria including pathogens and opportunists that may impact the survival of coral

50 How do corals influence the composition and/or functions of the associated microbiota? To effectively structure the associated microbiota, hosts must either (i) be able to detect specific micro-organism associated molecular patterns (MAMPs) (ii) excrete broadly active antimicrobial compounds to select against general environmental organisms, (iii) release chemical cues and/or nutrients attract micro-organisms with potentially beneficial functions, (iv) attract and maintain keystone microbes which is resistant to invasions by potential pathogens

51 How do corals influence the composition and/or functions of the associated microbiota? Strong evidence for scenarios (i) and (ii) would indicate that the composition of the associated microbiota is more important, scenarios (iii) and (iv) would argue that the function, rather than composition of the microbiota is more consequential to the holobiont s health and stability.

52 (i) be able to detect specific micro-organism associated molecular patterns (MAMPs) I. Their surface structures (lipopolysaccharide, peptidoglycan, flagellin, etc.) II. Genomes of Cnidarians encode homologues of proteins capable of recognizing micro-organisms and their associated molecular patterns (ii) excrete broadly active antimicrobial compounds to select against general environmental organisms, For example: Antimicrobial peptide Damicornin was most active against a fungus and some (but not all) Gram-positive bacteria, and had no effect on the four tested vibrios

53 (iii) release chemical cues and/or nutrients that would attract micro-organisms Organic extracts of the coral Siderastrea siderea showed selective antimicrobial activity against two of four strains of Gram-positive bacteria isolated from coral surfaces Exposure of corals to pathogens also induces production of enzymes with predicted defence functions: Phenoloxidase, Peroxidases Chitinases, Melanin

54 Coral microbiota can change based on environmental conditions Contact between corals and macroalgae can lead to changes in microbial assemblages in corals Macroalgae may affect coral-associated microbes by (i) smothering coral tissues or creating persistent hypoxic conditions (ii) poisoning any member of the coral holobiont via algal secondary metabolites (iii) Harbouring pathogenic bacteria (iv) inhibiting or stimulating microbial growth by releasing dissolved organic carbon or antibiotic secondary metabolites

55 Diversity of marine bacteria associated with Soft Coral The major bacteria Nitrogen-fixing Bioluminescent Gliding myxobacteria 38 % Gamma proteabacteria 17% Alpha proteabacteria 13 % CFP Group* 6% Cyanobacteria CFP Group*: includes: cytophagea,flavobacter/flexibacter, bacteriodes

56 Microbial Community Associated with the Zoanthid Palythoa australiae from the South China Sea

57 Phylogenetic tree of identified isolates associated with the soft coral Sarcophyton glaucum

58 Marine actinobacteria associated with marine organisms Large number of new compounds with pharmacological potentials from the actinobacteria associated with the marine organisms polyketides, isoprenoids, phenazines, peptides, indolocarbazoles, and sterols

59 Distribution and abundance of actinobacteria associated with the marine organisms

60 Natural products derived from the marine organism-associated actinobacteria

61 Distribution of natural product-producing actinobacteria associated with the marine organisms All these natural products were isolated from the genera belonging to Actinomycetales

62 Polyketide Synthases : PKSs are a family of large, modular enzymes that produce PKs, a large class of secondary metabolites, in bacteria, fungi, plants and vertebrate lineages PKSs found in I. actinobacteria, II. mycobacteria, III. pseudomonas IV. cyanobacteria Polyketide synthases are a class of enzymes that are involved in the biosynthesis of secondary metabolites (erythromycin, rapamycin, tetracycline, lovastatin, and resveratrol)

63 Non-Ribosomal Peptide Synthetase NRPs are peptide-derived molecules not produced by the ribosome but synthesised by assembly-line enzymes (NRPSs) whose function is similar to that of PKSs

64 In 2013, 1163 new marine compounds BUT only eight approved drugs of bacterial orgin 12 NPs (or derivatives) in different clinical phases

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66 تکنیک های جداسازی و کشت اکتینوباکترهای دریا.

67 why more than 70 bacterial phyla have no cultured representatives 1% of coral bacteria can presently be cultured Many organisms require special growth parameters (physical and chemical) that are hard or even impossible to reproduce in the laboratory

68 Our knowledge is still poor about specific, natural nutrients and growth factors required for their cultivation. I. Common media constituents such as simple sugars, peptone replaced with complex carbon sources such as chitin, sulfated polysaccharides, and marine proteins I. Effects of uncommon inorganic elements, such as lithium, silicon, etc., which are also abundant in marine sediments.

69 Marine metagenomics, a valuable tool for enzymes and bioactive compounds discovery

70 Metagenomics The enormous potential in diversity of the marine life is still not fully exploited due to the difficulty in culturing many of the microorganisms under laboratory conditions. Using metagenomics technique to access the uncultured majority of microbial communities

71 Culture-free techniques Using database sequences as a starting point, I. we can clone biosynthetic genes directly from the symbiosis II. and reconstitute them in a heterologous host for expression and compound production

72 Metagenomic-based strategies are powerful tools to isolate and identify enzymes with novel biocatalytic activities from the uncultivable component of microbial communities

73 Culture-free techniques I. 16S r DNA library was constracted by isolation of DNA directly from the coral sample, II. PCR amplification with bacterial-specific primers III. coloning I. We can obtain sequence information from ribosomal RNA (rrna) genes directly from the symbiosis without cultivation, II. and design specific oligonucleotide probes from these sequences

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75 Metagenomics may be focused on gene clusters or genes encoding enzymes and on the discovery of biocatalysts for synthesis and production of secondary metabolites like bioactive compounds

76 S AVE OUR CORAL