Background Penaeus monodon is the second most widely cultured marine shrimp species in the global shrimp aquaculture industry. However, the growth of P. monodon production has been constantly impaired by disease outbreaks. Recently, there is a lethal bacterial infection, known as acute hepatopancreatic necrosis disease (AHPND) caused by Vibrio parahaemolyticus AHPND strain ( Vp AHPND ), which led to mass mortalities in P. monodon . Unfortunately, there is still insufficient knowledge about the underlying immune response of P. monodon upon AHPND infection. The present study aims to provide an insight into the antibacterial immune response elicited by P. monodon hepatopancreas towards AHPND infection. Methods We have employed high-throughput RNA-Seq technology to uncover the transcriptome changes of P. monodon hepatopancreas when challenged with Vp AHPND . The shrimps were challenged with Vp AHPND through immersion method with dissected hepatopancreas samples for the control group (APm-CTL) and treatment group at 3 (APm-T3), 6 (APm-T6), and 24 (APm-T24) hours post-AHPND infection sent for RNA-Seq. The transcriptome de novo assembly and Unigene expression determination were conducted using Trinity, Tgicl, Bowtie2, and RSEM software. The differentially expressed transcripts were functionally annotated mainly through COG, GO, and KEGG databases. Results The sequencing reads generated were filtered to obtain 312.77 Mb clean reads and assembled into 48662 Unigenes. Based on the DEGs pattern identified, it is inferred that the PAMPs carried by Vp AHPND or associated toxins are capable of activating PRRs, which leads to subsequent pathway activation, transcriptional modification, and antibacterial responses (Phagocytosis, AMPs, proPO system). DAMPs are released in response to cell stress or damage to further activate the sequential immune responses. The comprehensive interactions between Vp AHPND , chitin, GbpA, mucin, chitinase, and chitin deacetylase were postulated to be involved in bacterial colonization or antibacterial response. Conclusions The outcomes of this research correlate the different stages of P. monodon immune response to different time points of AHPND infection. This finding supports the development of biomarkers for the detection of early stages of Vp AHPND colonization in P. monodon through host immune expression changes. The potential genes to be utilized as biomarkers include but not limited to C-type lectin, HMGB1, IMD, AL...

The possibility of using flocculation technique for the separation of microalgae, Chaetoceros calcitrans, biomass from the culture broth was investigated. The flocculation experiments were conducted in 500 mL beaker using culture broth obtained from 10 L photobioreactor. The harvesting efficiency of 90 and 60% was obtained in flocculation without flocculants conducted for 10 days at 27ºC (in light and dark) and 4ºC (dark), respectively. Harvesting efficiency higher than 90% with short settling time was achieved by adjusting the culture pH to 10.2 using either sodium hydroxide (NaOH) or potassium hydroxide (KOH). Improved cell viability (> 80%) and settling time with a slight improvement of flocculation efficiency was achieved by the addition of polyelectrolytes flocculant (Magnafloc ® LT 27 and LT 25). However, the flocculants were only functioned when the pH of the microalgae culture was pre-adjusted to a certain value that promotes cells entrapment and surface charge neutralization prior to flocculation process. The flocculation efficiency and cell viability obtained in flocculation with Magnafloc ® (LT 25 and LT 27) was comparable to that obtained in flocculation with chitosan. When chitosan and Magnafloc ® (LT 25 and LT 27) were used as flocculants, the highest flocculation efficiency of C. calcitrans cells was observed at pH 8 and 10.2, respectively. Substantial increased in sedimentation rate was observed with increasing flocculants dosage though the flocculation efficiency and cell viability were not significantly varied.

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Penaeid bacterial septicemia in juvenile market:-size tiger shrimp, Penaeus monodon, on three brackishwater pond farms in Jahore, Malaysia, is described. Histologically, tissue changes typical of experimental Gram-negative bacterial infections in marine crustaceans were observed in affected shrimp. Vibrio alginolyticus, V. parahaemolyticus, Pseudomonas sp., and other Gram-negative bacteria were isolated in low numbers from the hemolymph. The diagnosis and control of penaeid bacterial septicemia are discussed.

Harmful microalgae and cyanobacterial bloom cause deteriorated water quality and raises severe health concerns. This study discussed the demonstrations of simplified bioanalytical tools to enhance the natural resources of microalgae and cyanobacteria, to be given its importance, and how this knowledge can be used for wealth creation. Three bioanalytical approaches; (1) gas chromatography-mass spectrometry (GC-MS), (2) Raman spectroscopy, and (3) universal plastid biomarker, were successfully incorporated in selected microalgae and cyanobacteria. GC-MS analysis via solvent extraction characterized the organic compounds such as hydrocarbons and silicones derivatives. Air-dried thin layer of microalgae and cyanobacteria analyzed in Raman spectroscopy corresponded to three major spectra peaks, which fingerprints saffron and carotene photosynthetic pigments. Lastly, the taxonomic classification was simplified via the plastid 23S ribosomal ribonucleic acid (rRNA) biomarker, whereby, the Neighbor-Joining tree showed a clear separation between the phylogenetic clade of brown and green microalgae (eukaryotic), and cyanobacteria (prokaryotic). In short, this simplified multi-approaches; using molecular biomarkers provided an accurate identification on the species of microalgae and cyanobacteria, chemical biomarkers GC-MS characterized the organic compounds for sustainable green technology in industrial application, and finally, Raman spectroscopy can be future developed as a miniaturized handheld device for field sample detection for its fingerprinting characterization.