Cloning, heterologous expression and characterisation of a recombinant cellobiohydrolase from Humicola insolens ATCC16454 in Pichia pastoris

A cellobiohydrolase gene from the thermophilic fungus Humicola insolens ATCC 16454 was expressed in the methylotrophic yeast Pichia pastoris X-33, and the biochemical properties of the recombinant protein were characterised. The full-length cDNA of the cellobiohydrolase gene avi2 was cloned into the P. pastoris expression vector pPICZαC and expressed extracellularly as a recombinant cellobiohydrolase protein with a molecular weight of approximately 52.3 kDa. The purified recombinant Avi2 enzyme displayed an optimal activity at 50°C and was found stable between temperatures of 30°C and 60°C. The optimal pH of the enzyme was pH 5.0. More than 80% of the enzyme activity was retained at pH values ranging from pH3.0 to pH9.0. Recombinant Avi2 enzyme showed its highest activity towards the substrates Avicel (0.075 U mg-1) and Sigmacell-cellulose (0.018 U mg-1). Very low or undetectable hydrolysis was observed with cellobiose and filter paper. Metal ions, such as Mn2+, Co2+, and Ba2+, increased the activity of the recombinant enzyme. Manganese ions caused the highest increase in activity of approximately 1.38-fold compared to the control assay. Other ions such as Pd2+, Cu2+, Zn2+, Fe2+, and SDS, however, inhibited Avi2 enzyme activity. Interestingly, this recombinant enzyme showed high pH stability when it was incubated in either acidic or basic solutions

Biochemical changes of cryopreserved seminal plasma and spermatozoa of the giant grouper Epinephelus lanceolatus after preservation and transportation using dry-ice

The present study aims to investigate the effects of exposure of the seminal plasma and spermatozoa of the giant grouper Epinephelus lanceolatus to dry ice ( 79 C) during transport on their quality. In all, 15 amino acid compounds were determined. The quantification of total proteins were measured using the Bradford method, and amino acid concentration were measured using the HPLC method. The cryopreserved seminal plasma was transferred from a liquid nitrogen tank to a styrofoam box filled with dry ice. Total protein and amino acids were measured after 24, 48, and 72 h. For comparative purposes, total protein and fifteen compound of amino acid were also measured. Both parameters were also measured after the cryopreserved seminal plasma were immersed in liquid nitrogen after 24 and 48 h exposed to dry ice. The results showed that the exposure of seminal plasma to dry ice for 24, 48 and 72 h during transportation or immersion back into the liquid nitrogen after 24 and 48 h does not change the total protein levels either in seminal plasma or spermatozoa. However, the level of each amino acid compound in the seminal plasma had significantly decrease

The genome sequence of Vibrio parahaemolyticus C5A causing acute hepatopancreatic necrosis disease in shrimps isolated from a Malaysia shrimp culture pond

We report the complete genome sequence of Vibrio parahaemolyticus strain C5A causing an acute hepatopancreatic necrosis disease (AHPND) in Penaeus vannamei sampled from a culture pond in the east of peninsular Malaysia isolated in 2017

DNA Barcoding and Phylogenetics Relationship of Pangasiid Catfishes in Peninsular Malaysia Revealed the Impacts of Aquaculture on the Native Species Conservation

Pangasiids are an economically significant group of catfish, and many pangasiids are threatened in the wild from anthropogenic pressures, including increases in fishing pressure, habitat degradation, and improperly managed aquaculture practices. This study demonstrates the usage of DNA barcoding of the Cytochrome Oxidase subunit I (COI) gene as an identification tool in detecting potentially threatening invasive pangasiid species by establishing the diversity and phylogenetic relationship of Pangasiidae catfishes in Peninsular Malaysia. A neighbour-joining (NJ) dendrogram (Kimura-2-parameter model) generated five clades to represent distinct genera. Pangasius was further subdivided into two clades (Clade A: Pangasius bocourti-P. djambal and Clade B: P. nasutus-P. conchophilus). Given the marginal genetic divergence, indigenous and non-native species should be treated cautiously in allopatrically distributed species. The analysis used Automatic Barcode Gap Discovery (ABGD) and revealed barcode gaps between the intraspecific and interspecific distances. The sequences were partitioned into five groupings, corresponding with the species delineation based on the distribution of pairwise differences, which could not be differentiated using the NJ dendrogram. ABGD allows the recognition of one or two additional species using the recursive approach, but other taxonomic methods should be considered for a solid conclusion. DNA barcoding demonstrates the identification of closely related species, thus justifying its application towards the conservation of these fish

Draft genome sequence data of Vibrio harveyi VH1 isolated from a diseased tiger grouper, Epinephelus fuscoguttatus, cultured in Malaysia

Vibriosis accounts for 66.7% of diseases reported in groupers' cultures and affects almost all stages of growth. The disease could lead up to mortality up to 50% mortality, and it was reported that high stocking density and poor fish handling were among the factors that contributed to the disease dissemination. V. harveyi has been reported to be among the causative agent and has caused acute mortality in cage groupers. In this study, we report the genome of V. harveyi VH1 isolated from a diseased tiger grouper Epinephelus fuscoguttatus, reared in a cage farm located in the coastal area of Langkawi. (c) 2022 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/

Prevalence, Antibiotics Resistance and Plasmid Profiling of <i>Vibrio</i> spp. Isolated from Cultured Shrimp in Peninsular Malaysia

Vibrio is the most common bacterium associated with diseases in crustaceans. Outbreaks of vibriosis pose a serious threat to shrimp production. Therefore, antibiotics are commonly used as preventative and therapeutic measures. Unfortunately, improper use of antibiotics leads to antibiotic resistance. Nevertheless, information on the occurrence of Vibrio spp. and antibiotic use in shrimp, particularly in Malaysia, is minimal. This study aimed to provide information on the occurrence of Vibrio spp., its status of antibiotic resistance and the plasmid profiles of Vibrio spp. isolated from cultured shrimp in Peninsular Malaysia. Shrimp were sampled from seven farms that were located in different geographical regions of Peninsular Malaysia. According to the observations, 85% of the shrimp were healthy, whereas 15% were unhealthy. Subsequently, 225 presumptive Vibrio isolates were subjected to biochemical tests and molecular detection using the pyrH gene. The isolates were also tested for antibiotic susceptibility against 16 antibiotics and were subjected to plasmid profiling. Eventually, 13 different Vibrio spp. were successfully isolated and characterized using the pyrH gene. They were the following: V. parahaemolyticus (55%), V. communis (9%), V. campbellii (8%), V. owensii (7%), V. rotiferianus (5%), Vibrio spp. (4%), V. alginolyticus (3%), V. brasiliensis (2%), V. natriegens (2%), V. xuii (1%), V. harveyi (1%), V. hepatarius (0.4%) and P. damselae (3%). Antibiotic susceptibility profiles revealed that all isolates were resistant to penicillin G (100%), but susceptible to norfloxacin (96%). Furthermore, 16% of the isolates revealed MAR of less than 0.2, while 84% were greater than 0.2. A total of 125 isolates harbored plasmids with molecular weights between 1.0 and above 10 kb, detected among the resistant isolates. The resistant isolates were mediated by both chromosomal and plasmid factors. These findings support the use of surveillance data on the emerging patterns of antimicrobial-resistance and plasmid profiles of Vibrio spp. in shrimp farms. The findings from this study can be used to develop a better disease management strategy for shrimp farming

Genome sequence of Vibrio parahaemolyticus C5A causing acute hepatopancreatic necrosis disease in shrimp isolated from a Malaysian shrimp culture pond

We report the complete genome sequence of Vibrio parahaemolyticus strain C5A causing an acute hepatopancreatic necrosis disease (AHPND) in Penaeus vannamei sampled from a culture pond in the east of peninsular Malaysia isolated in 2017