Antiviral property of marine actinomycetes against White Spot Syndrome Virus in penaeid shrimps

Aquaculture farms, particularly in Southeast Asia are facing severe crisis due to increasing incidences of White Spot Syndrome Virus (WSSV). Actinomycetes have provided many important bioactive compounds of high prophylactic and therapeutic value and are continually being screened for new compounds. In this communication, the results of a study made to determine the effectiveness of marine actinomycetes against the white spot disease in penaeid shrimps are presented. Twenty-five isolates of actinomycetes were tested for their ability to reduce infection due to WSSV among cultured shrimps. When these actinomycetes were made available as feed additives to the post-larvae of the black tiger shrimp Penaeus monodon for two weeks and challenged with WSSV, the post challenge survival showed variations from 11 to 83%. However, six isolates have shown to be the most potential candidates for further study.

Marine Actinomycetes as Source of Antiviral Agents and as Probionts for Penaeus monodon Culture Systems

The present study revealed the importance of marine actinomycetes as a potent source of bio active secondary metabolites. The selected isolates were capable of protecting Peaneus monodon against WSSV infection. They also proved to be inhibitory to vibrios and is a rich pool of hydrolytic enzymes. Their capacity to proliferate in saline environments and their property of non-pathogenicity to prawns makes them good candidates to be applied as probionts in penaeid shrimp aquaculture. They also enhanced the immune status of shrimps challenged with WSSV and act as a good source of antioxidants. Exploitation of the potential for the prophylactic and therapeutic measures in aquatic animal health management would be highly rewarding. This work is a preliminary study targeting marine actinomycetes as a source of antiviral compounds and as probionts in Penaeus monodon culture systems. More work is needed to understand the nature and mode of action of the bioactive compound, the various aspects of immune and antioxidant responses under challenge and when exposed to pro active treatments, and the dose and frequency of application of such compounds under rearing conditions.

Marine Actinomycetes as Source of Antimicrobial Compounds and as Probiotics and Single Cell Protein for Application in Penaeid Prawn Culture Systems

This thesis Entitled Marine actinomycetes as source of antimicrobial compounds and as probiotics and single cell protein for application in penaeid peawn culture systems. Ocean harbours more than 80% of all life on earth and remains our greatest untapped natural resource. The study revealed the potential of marine actinomycetes as a source of antimicrobial compounds. The selected streptomycetes were found to be capable of inhibiting most of the pathogenic vibrios, whichis a major problem both in hatcheries and grow out systems. The bioactive principle can be incorporated with commercial feeds and applied as medicated diet for the control of vibrios in culture systems.The hydrolytic potential inhibitory property against pathogens and non—pathogenicity to penaeid prawns make the selected Streptomycesspp.an effective probioic in aquaculture. Since there is considerably less inhibition to the natural in pond ecosystem the microbial diversityis being maintained and thereby the water quality. Actinomycetes was found to be a good source of single cell protein as an ingredient inaquaculture feed formulations. Large amount of mycelial waste (actinomycete biomassO is produced from antibiotic industries and this nutrient rich waste can be effectively used as a protein source in aquaculture feeds.This study reveals the importance of marine actinomycetes as a source of antimicrobial compounds and as a probiotic and single cell protein for aquaculture applications.

Marine actinomycetes related to the 'Salinospora' group from the Great Barrier Reef sponge Pseudoceratina clavata

Ten strains identified as marine actinomycetes related to the 'Salinospora ' group previously reported only from marine sediments were isolated from the Great Barrier Reef marine sponge Pseudoceratina clavata. The relationship of the isolates to 'Salinospora' was confirmed by phylogenetic analysis of 16S rRNA gene sequences. Colony morphology and pigmentation, occurrence and position of spores, and salinity requirements for growth were all consistent with this relationship. Genes homologous to beta-ketosynthase, an enzyme forming part of a polyketide synthesis complex, were retrieved from these isolates; these genes shared homology with other Type I ketosynthase genes, and phylogenetic comparison with amino acid sequences derived from database beta-ketosynthase genes was consistent with the close relationship of these isolates to the actinomycetes. Primers based on 16S rRNA gene sequences and designed for targeting amplification of members of the 'Salinospora' group via polymerase chain reaction have been used to demonstrate occurrence of these actinomycetes within the sponge tissue. In vitro bioassays of extracts from the isolates for antibiotic activity demonstrated that these actinomycetes have the potential to inhibit other sponge symbionts in vivo, including both Gram-negative and Gram-positive bacteria.

Chandrananimycins A-C: Production of novel anticancer antibiotics from a marine Actinomadura sp isolate M048 by variation of medium composition and growth conditions

In our screening of marine actinomycetes for bioactive principles, three novel antibiotics designated as chandrananimycin A (3c), B (3d) and C (4) were isolated from the culture broth of a marine Actinomadura sp. isolate M045. The structures of the new antibiotics were determined by detailed interpretation of mass, 1 D and 2 D NMR spectra.

Two anthraquinone compounds from a marine actinomycete isolate M097 isolated from Jiaozhou Bay

Two anthraquinone compounds were isolated from the culture broth of a marine actinomycete isolate M097. The structures were elucidated as Aloesaponarin II and 1,6-dihydroxy-8-hydroxymethyl-anthraquinone by detailed interpretation of their spectra. It is the first time that the latter has ever been reported as a secondary metabolite from a wild-type strain. The results showed that the actinomycete isolate M097 could be a promising material for studying the biosynthetic pathway of polyketides and the production of novel recombinant polyketides.

三种海洋红藻和两株放线菌次级代谢产物研究

海洋是一个巨大的天然产物宝库，约占地球表面积70%的海洋蕴藏着80%的生物资源。由于海洋生态环境的特殊性，导致海洋生物能够产生大量结构独特多变和活性特殊多样的代谢产物。我国海域辽阔，海洋资源丰富，为寻找结构新颖、生理活性独特的先导化合物，加强对海洋资源的开发利用，本论文对中国沿海的三种海洋红藻和两株放线菌次生代谢产物以及生物活性进行研究，为新药研究与开发提供模式结构和药物前体。 对红藻似瘤凹顶藻Laurencia similis乙酸乙酯萃取物进行分离纯化，从中得到单体化合物35个，通过波谱学方法（IR、MS、NMR等）鉴定了他们的结构。分别为：2, 2, 5, 5, 6, 6-sixibromo-3, 3-bi-1H-indole (1)，3,5-dibromo- 1-methyl-indole (2)，3',5',6,6'-tetrabromo-2,4-dimmethyldiphenyl ether (3)，1,2,5- tribromo-3-bromoamino-7-bromomethylnaphthalene (4)，2,5,8-tribromo-3-bromo- amino-7-bromomethylnaphthalene (5)，2,5,6-tribromo-3-bromoamino-7-bromo- methylnaphthalene (6), 2,5,6,5',6'-pentabromo-3,4,3',4'-tetramethoxybenzophenone (7), (4E)-1-bromo-5-[(1'S*,3'R*)-3'-bromo-2',2'-dimethyl-6'-methylenecyclohexyl] -3-methylpent-4-ene-2,3-diol (8)，4-hydroxy-Palisadin C (9)，Isopalisol (10)，Luzonensol (11)，Palisadin B (12)，Aplysistatin (13)，Palisadin A (14)，5-Acetoxypalisadin B (15)，Aristolan-1(10)- en-9-ol (16)，Aristol-8-en-1-one (17)，Aristolan-9-en-1-one (18)，Aristolan-1(10)-en- 9-one (19)，Aristofone (20)，Aristolan-1(10)-8-diene (21)，Aristolan-1,9-diene (22)，10-Hydroxyaristolan-9-one (23)，7,11,15-trimethyl-3-methylene-hexadecan-1,2-diol (24)，3β-Hydroxyergosta- 5,24(28)-dien-7-one (25)，Isofucosterol (26)，β-sitosterol (27)，豆甾-4-烯-3α,6β-二醇 (28)，Cholesta-5-en-3β-ol (29)，Stigmasterol (30)，2,3,5,6-四溴-吲哚 (31)，2,3,6-tribromo-1H-indole (32)，3,5,6-tribromo-1-methylindole (33)，3,5,6-tribromo -1H-indole (34)，2,3,5-tribromo-1-methylindole (35)，其中化合物1-9为新化合物，化合物10-15、20和化合物24-30均为首次从该种海藻中得到。对新化合物1-9进行PTP1B酶抑制剂活性筛选，新化合物1、3、7显示强的PTP1B酶抑制活性。 对红藻齐藤凹顶藻Laurencia saitoi乙酸乙酯萃取物进行分离纯化，从中得到单体化合物11个，通过波谱学方法（IR、MS、NMR等）鉴定了他们的结构，分别为：2-hydroxyl-Luzofuranone (1)，2-hydroxyl-Luzofuranone B (2)，4-hydroxyl-Palisudin C (3)，2-bromo-γ-ionone (4)，Aplysistatin (5)，5-Acetoxypalisadin B (6)，Palisadin B (7)，Palisadin A (8)，Pacifigorgiol (9)，豆甾-4-烯-3α,6β-二醇 (10)，2, 3, 5, 6-四溴-吲哚 (11)，其中化合物1-4为新化合物，所有化合物均为首次从该种海藻中得到。通过MTT法对分离得到的新化合物1-4进行肿瘤细胞毒活性筛选，结果显示4个新化合物对所测肿瘤细胞株均无明显的活性。 对红藻瘤状软骨凹顶藻Chondrophycus papillous乙酸乙酯萃取物进行分离纯化，从中得到单体化合物5个，通过波谱学方法（MS、NMR等）鉴定了他们的结构，分别为邻苯二甲酸二丁酯 (1)，邻苯二甲酸二异辛酯 (2)，胆甾醇 (3)，3,7,11,15-tetramethyl-hexadec-2-en-1-ol (4)，4-羟基苯甲醛 (5)，所有化合物均为首次从该种海藻中得到。 对海洋放线菌M159乙酸乙酯萃取物进行分离纯化，从中得到单体化合物13个，通过波谱学方法（MS、NMR等）鉴定了他们的结构，分别为：5-(4',6'-dihydroxy-6-methyloctyl)furan-2(5H)-one (A)，phenethyl alcohol (1)，4-羟基苯甲醛(2)，anthranilic acid (3)，4-Hydroxy-3-methoxy- phenyl-propionic acid (4)，5-(6,7-dihydroxy-6-methyloctyl)furan-2(5H)-one (5)，p-Hydroxyphenylethyl alcohol (6)，3-Indoleacrylic acid (7)，Indol-3-carboxylic acid (8)，Adenine cordyceposide (9)，腺嘌呤核苷(10)，尿嘧啶核苷(11)，Thymidine (12)，其中化合物A为新化合物。所有化合物均为首次从该株放线菌中得到。 对海洋放线菌L211乙酸乙酯萃取物进行分离纯化，从中得到单体化合物15个，通过波谱学方法（MS、NMR等）鉴定了7个结构，分别为：spatozoate (1)，anthranilic acid (2)，3-Indolylethanol (3)，1-Acetyl-β-carbolin (4)，p-Hydroxyphen- ylethyl alcohol (5)，Indole-3-acetic acid (6)，Indol-3-carboxylic acid (7)，所有化合物均为首次从该株放线菌中得到。

Actinomycete Isolates from Arabian Sea and Bay of Bengal: Biochemical, Molecular and Functional Characterization

The thesis is comprised of seven chapters. Chapter 1 gives a general introduction to marine actinomycetes; Chapter 2 gives an account on the morphological, biochemical and physiological characterization of marine actinomycetes. Comprehensive description of molecular identification and phylogenetic analysis of actinomycetes is dealt with in Chapter 3. The antimicrobial property with special reference to antivibrio activity is described in Chapter 4. Chapter 5 explores the melanin production ability of marine actinomycetes, characterization of melanin and evaluation of its bioactivity. Chapter 6 illustrates the study on chitinolytic Streptomyces as antifungal and insecticidal agents. Summary and Conclusion of the study is presented in Chapter 7, followed by References and Appendices.The present study provides an insight into the various actinomycetes occurring in the sediments of Arabian Sea and Bay of Bengal. Streptomyces was found to be the dominant group followed by Nocardiopsis. Eventhough generic level identification is possible by traditional phenotypic methods, species level identification necessitate a polyphasic approach including both phenotypic and genotypic characterization. Antibiotic production coupled with biogranulation property helped in the effective utilization of the actinomycetes for the control of vibrios. Melanin from Streptomyces bikiniensis was proved to be a promising antioxidant and photoprotectant. Marine actinomycetes were found to be a good source of hydrolytic enzymes and the chitinolytic isolates could be explored as biocontrol agents in terms of antifungal and insecticidal property. The present study explored the potential of marine actinomycetes especially Streptomycetes as a promising source of bioactive molecules for application in aquaculture and pharmaceutical industry.

Diversity of Bacillus And Actinomycetes in the water and sediment samples from Kumarakom region of Vembanadu lake

Diversity of different groups of Bacillus and Actinomycetes in the water and sediment samples from kumarakom estuary was analysed to find out potential strains for further application. Bacillus genera was identified and grouped into five phenogroups .Phenogroups show differences in the shape of the spore,position of the spore,and swelling of the sporangium.Ability of the isolates to elaborate various hydrolytic enzymes and their ability to reduce nitrate and ferment various carbohydrate sources were also studied.

Brucite Microbialites in Living Coral Skeletons: Indicators of Extreme Microenvironments in Shallow-Marine Settings

Brucite [Mg(OH)2] microbialites occur in vacated interseptal spaces of living scleractinian coral colonies (Acropora, Pocillopora, Porites) from subtidal and intertidal settings in the Great Barrier Reef, Australia, and subtidal Montastraea from the Florida Keys, United States. Brucite encrusts microbial filaments of endobionts (i.e., fungi, green algae, cyanobacteria) growing under organic biofilms; the brucite distribution is patchy both within interseptal spaces and within coralla. Although brucite is undersaturated in seawater, its precipitation was apparently induced in the corals by lowered pCO2 and increased pH within microenvironments protected by microbial biofilms. The occurrence of brucite in shallow-marine settings highlights the importance of microenvironments in the formation and early diagenesis of marine carbonates. Significantly, the brucite precipitates discovered in microenvironments in these corals show that early diagenetic products do not necessarily reflect ambient seawater chemistry. Errors in environmental interpretation may arise where unidentified precipitates occur in microenvironments in skeletal carbonates that are subsequently utilized as geochemical seawater proxies.