Construction and Analysis of Metagenome Library from Bacterial Community Associated with Toxic Dinoflagellate <em>Alexandrium tamiyavanichii</em>

Previous studies have suggested that a specific community of bacteria coexists within the phycosphere of marine dinoflagellates. In order to better understand the dinoflagellate-bacteria relationships, a fosmid clone library was constructed from the metagenome DNA and analyzed. Some of the fosmid clones were end-sequenced. A total of 1501 fosmid clones with insert sizes of 30–40 Kbp were produced. End sequencing of 238 clones showed that 55% of the genes had known functions, 11% were of putative function and 34% were genes of unknown function or had no match in Genbank. There were approximately 14% sequences with no classification and could potentially represent novel genes. Analysis of these partial sequences also revealed some promising enzymes that possess various potential industrial applications such as chitinases, kinases, agarases and oxygenases. The results also showed that the bacterial flora of the Alexandrium tamiyavanichii culture was dominated by the Alpha-proteobacteria, followed by Bacteroidetes and Gamma-proteobacteria. The findings in this study suggested that the bacterial community may play various role in the association with dinoflagellate. This study had also shown that dinoflagellate-associated bacterial community is a valuable source for discovery of novel genes and gene products

Immune and bacterial toxin genes expression in different giant tiger prawn, Penaeus monodon post-larvae stages following AHPND-causing strain of Vibrio parahaemolyticus challenge

Acute Hepatopancreatic Necrosis Disease (AHPND), a disease caused by Vibrio parahaemolyticus (V-PAHPND), kills Penaeid shrimps worldwide, resulting in severe economic losses during aquaculture. To further understand how Penaeus monodon post-larvae (PL) respond towards infection of this pathogenic bacterium, the expression of several important immune and bacterial toxin genes in three stages of P. monodon PL (PL15, PL30 and PL45) upon V-PAHPND challenge, were determined. A 20-hrs challenge test with 2.7 x 10(7) cfu ml(-1) of V-PADPND resulted 81, 65 and 1.7% mortality respectively for PL30, PL15 and PL45, indicating that PL30 was most vulnerable to V-PADPNEP The immune response of shrimp PL at this stage was robust, with Toll-like receptor (TLR), prophenoloxidase (proPO), lysozyme (lyso) and penaeidin (PEN) augmented approximately 10.7, 4.7, 6.5 and 3.2-fold, respectively. The expression initiated at one hour post-infection (h.p.i), peaked at 16 h.p.i and 20 h.p.i, and decreased at 18 h.p.i, indicating the crucial involvement of these immune related genes in the defence and recovery of the first-line defence mechanisms during V-PADPND infection. This work also revealed that toxR gene represents a good indicator gene for Vibrio detection whereas PIR A, for V-PADPND pathogenicity determination of P. monodon. Overall, these findings provided novel insights into the immune response and V-PADPND No susceptibility of different P. monodon PL stages during infection, with outcomes potentially useful in enhancing the application of health therapy and biosecured aquaculture practices to minimize the damaging risk of AHPND towards sustainable production of P. monodon

Transcriptome profile and pathway analysis of starch and sucrose metabolism in Euglena gracilis

Euglena gracilis, a single cell flagellate eukaryote, produces secondary metabolites known as paramylon, a carbohydrate similar to starch with beneficial health properties. In this study, we sequenced the transcriptome and identified the pathways and key enzymes involved in the starch and sucrose metabolism of E. gracilis. A total of 120,086 unigenes were assembled with the Trinity software, of which 48,031 were annotated. The genes involved in the starch and sucrose metabolism of E. gracilis were further identified, leading to the construction of a preliminary pathway map of starch metabolism for this single cell flagellate eukaryote species. Both β-amy and Spase2 were identified to play major roles in starch catabolism, whereas glucose-1-phosphate adenylyltransferase functions in starch anabolism. It is anticipated that the starch content of E. gracilis can either be augmented by inhibiting the starch breakdown with β-amy or Spase2 gene interference or by elevating the level of AGPase activity of Glucose-1-phosphate transferase to promote starch anabolism. Whatever the outcomes, results from this study provided a fundamental understanding on how E. gracilis regulates its starch metabolic pathways, and the impact of genetic modification on starch synthesis

Applications of next-generation sequencing technologies and computational tools in molecular evolution and aquatic animals conservation studies : a short review

Aquatic ecosystems that form major biodiversity hotspots are critically threatened due to environmental and anthropogenic stressors. We believe that, in this genomic era, computational methods can be applied to promote aquatic biodiversity conservation by addressing questions related to the evolutionary history of aquatic organisms at the molecular level. However, huge amounts of genomics data generated can only be discerned through the use of bioinformatics. Here, we examine the applications of next-generation sequencing technologies and bioinformatics tools to study the molecular evolution of aquatic animals and discuss the current challenges and future perspectives of using bioinformatics toward aquatic animal conservation efforts

Live foods for juveniles production of blue swimming crab, Portunus pelagicus (Linnaeus, 1766)

The study were aim to demonstrate the affects of live food type’s i.e., mixed diatom, Artemia nauplii and rotifer on survival rate and molt time of larvae stage till 1st day juvenile crabs (C1) of P. pelagicus. Three types of feeding regimes given to the crab larvae through out the study trials are with and without mixed diatom, with and without Artemia nauplii and with and without rotifer. The study shows that zoea fed with rotifer alone was not enough to sustain survival in the next zoea stages and to promote metamorphosis up to megalopa stage. Survival of zoea fed with Artemia nauplii alone shows that this type of food is not suitable for the very early zoea stages. The study also shows that the adding of mixed diatom to larvae rearing system where rotifer and Artemia nauplii is main food items did not produced high survival rate as compared to larvae rearing fed on rotifer and Artemia nauplii alone. The results of the study demonstrated that the food types not only effect survival rate but also the growth of crab larvae. The study generally ended that the combination diet of rotifer and Artemia nauplii alone is enough to produced C

Antioxidant capacity of five microalgae species and their effect on heat shock protein 70 expression in the brine shrimp Artemia

Oxidative stress caused by chemicals brings about mass mortalities in aquatic organisms and in this context, antioxidants and heat shock protein 70 (Hsp70) stimulating compounds represent potential alternatives to alleviate this problem during aquaculture. The antioxidant capacity and efficacies of five Malaysian indigenous microalgae, namely Auxenochlorella pyrenoidosa, Chlorella vulgaris, Messastrum gracile, Desmodesmus subspicatus and Parachlorella kessleri to regulate Hsp70 expression in the brine shrimp Artemia, an important live food species, were examined. A. pyrenoidosa contained the highest total phenol and flavonoid content (48.3 mg GAE/g extract and 34.7 mg QE/g) across all the microalgae examined in this study, whereas the lowest occurred with C. vulgaris (24.4 mg GAE/g extract and 14.0 mg QE/g). The ferric reducing antioxidant power of A. pyrenoidosa, C. vulgaris, M. gracile, D. subspicatus and P. kessleri respectively stood at 0.78, 0.62, 1.01, 0.77 and 0.68 ferrous equivalents (mM), with trolox equivalent antioxidant capacity assay revealed that A. pyrenoidosa possessed the highest scavenging activity at 1 mg/mL concentration. Interestingly, application of 1.0-2.0 x 10(6) cells/mL C. vulgaris, M. gracile, D. subspicatus, and P. kessleri as feed enhanced Hsp70 accumulation in Artemia, indicating that these microalgae consist stimulating compound(s) which potentially promote the synthesis of the 70-kDa stress protein in this crustacean species. Taken together, results from this study revealed that microalgae possess various antioxidant properties and coupled with their abilities to induce Hsp70, they are potential oxidative stress control alternatives in Artemia and perhaps other aquatic organisms used in aquaculture

Induction of apoptosis and role of paclitaxel-loaded hyaluronic acid-crosslinked nanoparticles in the regulation of AKT and RhoA

Cancer is a complex multifactorial disease and leading causes of death worldwide. Despite the development of many anticancer drugs, there is a reduced survival rate due to severe side effects. The nontargeted approach of convention drugs is one of the leading players in context to toxicity. Hyaluronan is a versatile bio-polymer and ligand of the receptor (CD44) on cancer cells. The MCF-7 and HT-29 cancer cell lines treated with hyaluronic acid-paclitaxel (HA-PTX) showed the distinguishing morphological features of apoptosis. Flow cytometric analysis showed that HA-PTX induces apoptosis as a significant mode of cell death. The activation level of tumor suppressor protein (p53) increased after PTX treatment in MCF-7, but no changes observed in HT-29 might be due to hereditary mutations. The lack of suppression in AKT and Rho A protein suggest the use of possible inhibitors in future studies which might could play a role in increasing the sensitivity of drug towards mutated cells line and reducing the possibilities for cancer cell survival, migration, and metastasis

A review of mercury pathological effects on organs specific of fishes

Rapid development has been associated with mercury pollution in the aquatic environment, leading to mercury toxicity in fish and other aquatic organisms. Histopathological abnormalities such as hyperplasia, inflammation, and necrosis have been observed in various fish tissues as a result of mercury contamination based on organic mercury (methylmercury) and inorganic mercury (mercuric chloride) exposure via dietary or water exposure, respectively, with different duration doses of mercury. Knowing that tissue changes occurred at an important part of each organ that played various critical roles in the normal physiological actions of fish, it is critical to understand how fish respond to mercury contamination and how this heavy metal element affects their general well-being. This review paper focuses on major tissue histopathology changes in response to mercury toxicity and their potential use as a mercury contamination indicator in fish

Abundance and ecological footprint of Pseudoalteromonas phage vB_PhoS_XC in the Ulva prolifera green tide

Pseudoalteromonas is a ubiquitous and abundant genus of marine bacteria commonly associated with algae. In this study, a novel siphoviral-morphological bacteriophage, vB_PhoS_XC, was isolated from the coastal seawaters of Qingdao (China) during a bloom of the Ulva prolifera (U. prolifera) green tide. The morphology of this phage (icosahedron head 51 ± 1 nm in diameter; a tail length of 86 ± 1 nm) was characterized through transmission electron microscope. The biological properties of this virus showed a short latent period (45 minutes), a large burst size (241 virions per cell) and a relatively wide range of temperatures/pH level tolerance (-20°C to 45°C and pH 4 to pH 10, respectively). The vB_PhoS_XC has a 46,490-bp double-stranded DNA genome with a G+C content of 40.0%, and encodes 72 open reading frames (ORFs). Thirty-five of these ORFs were assigned into known functions based on BLAST-based algorithm against NR database of GenBank. In addition, eco-genomic analysis provides the evidence of vB_PhoS_XC accompanied by bloom of U. prolifera, and confirmed the high expression of two phosphatase-metabolism-related auxiliary metabolic genes (AMGs). This study provides new insights into the functional and ecological roles of the Pseudoalteromonas phage vB_PhoS_XC, shedding light on the virological study approach combined with traditional isolation and meta-omics data