Molecular characterization of 16S rRNA and internal transcribed spacer (ITS) regions of Aeromonas spp. isolated from cultured freshwater fishes in Malaysia

The Aeromonas spp., which are found mostly in freshwater fishes are known to cause uncontrolled disease outbreak in aquaculture system. In the present study, twenty-two of Aeromonas spp. strains isolated from diseased freshwater fishes were identified using the 16S ribosomal RNA (rRNA) and internal transcribed spacer (ITS) regions gene amplification where they produced a 1500 bp and 1000-1200 bp amplicon each. Phylogenetic analysis with BLASTn and 16S rRNA neighbor-joining bootstrapping methods revealed that all strains were identified up to genus level with 15 strains were classified as Aeromonas hydrophila (A. hydrophila) and the rest were Aeromonas veronii (A. veronii). Further ITS gene analysis disclosed strains identification up to species level; A. hydrophila (14 strains) and A. veronii (8 strains). These rapid DNA-based detection methods are simple, easy to perform and faster in identifying Aeromonas spp., thus are absolutely efficient for regular monitoring of Aeromonas spp. in a potential outbreak situation

A prospect of using Vibrio harveyi isolated from the intestine of healthy farmed Tiger Grouper, Epinephelus fuscoguttatus (Forsskal, 1775) as probiotics

Two bacterial strains Vibrio harveyi JAQ01 and JAQ02 isolated from the intestine of farmed Tiger Grouper (Epinephelus fuscoguttatus) were studied to illustrate their in vitro characteristics as probiotics. Phenotypic characterization of the test strains was performed following a standard physiological test aided by commercial identification kits. A comparative phenotypic data between the test strain and a reference strain V. harveyi ATCC35084 was generated. These bacterial strains were eventually designated as V. harveyi JAQ01 and JAQ02 following 16S rRNA gene sequences analysis. Both strains were successfully exhibited a significance level of inhibition of target strains using a modified bacteriocin-like inhibitory substance (BLIS) method to fulfill their functional requirement as probiotics. Assessment on the safety aspects regarding their haemolytic activity and antibiotic resistance profile completed this study. Our investigation revealed the presence of two antagonists V. harveyi that may play a role in diseased control of farmed E. fuscoguttatus. This is the first report made to assess in vitro characterization of intestinal V. harveyi of farmed E. fuscoguttatus suggesting the prospect of using V. harveyi JAQ01 and JAQ02 in aquaculture is worth an advance research

Protein identification of vitellogenin in river catfish (Hemibagrus nemurus)

Mass production of fish broodstock with high quality eggs requires the knowledge on the chemical composition and physiochemical properties of vitellogenin (Vtg) during ovulation. Vtg is an egg yolk precursor phospholipoglycoprotein, and has been analysed to evaluate the reproductive conditions and determine the spawning period in captive and wild fish. In this study, Vtg was induced in male H. nemurus through three intramuscular injections of 17- estradiol (E2). The Vtg was purified from the serum using gel filtration chromatography and thepurified protein was reduced via SDS-PAGE. One major polypeptide corresponding to 130 kDa was observed. Vtg identification was done using peptide mass fingerprint (PMF) from the trypsin digestion of male H. nemurus Vtg induced with E2. The sequence homology of H. nemurus AYLAGAAADVLEVGVR matched the Vtg of other fish species when analysedusing MALDI-TOF. Vtg was confirmed by MASCOT at 95% significant level. The potential protein that controls the reproductive process and oocyte development isolated from this study was discussed to understand the structure and function of Vtg

Positive Affectivity and Employee Engagement: Mediating Role of Social Support

Purpose: Previous studies have found that employees’ positive affectivity personality contributes to positive organizational outcomes. However, little is known about the mechanisms by which positive affectivity is related to social support and employee engagement. Therefore, drawing on the conservation of resources theory, this study examined the role of social support as a mediator that links positive affectivity and employee engagement. Method: The study was conducted using a quantitative approach. It used a survey method to collect data from 260 professional registered nurses in public hospitals in Lagos, Nigeria, who were selected as research participants using a stratified random sampling technique. Result: The structural model analysis revealed that positive affectivity significantly affects social support and employee engagement. Also, social support significantly correlates with employee engagement and partially mediates the relationship between positive affectivity and employee engagement. Implications: The findings of this study contributed to the limited literature on positive affectivity, social support, and employee engagement. Practically, this study has implications for clinical practice and management. To enhance employee engagement among nurses, hospital administrators should develop intervention programs that can enhance the nurses' ability to maintain positive emotions in stressful situations

Identification and characterization of the lactic acid bacteria isolated from Malaysian fermented fish (Pekasam)

Recently researchers are interested with the biotherapeutic potential of probiotics in gut disease treatment. The bacteria are generally regarded as a safe, have a stability of usage and originate from the natural resources. The study aims to identify and characterize the potential probiotic Lactic Acid Bacteria (LAB) isolated from Malaysian fermented fish product known as Pekasam. Fourty isolates obtained were firstly screened for their antagonism activities against the common pathogenic bacteria; Esherichia coli, Staphylococcus aureus and Klebsiella sp. Our study revealed only three (labeled as L8, L20 and S1) of the isolates tested showed broad antimicrobial effects towards the pathogenic bacteria. All of the isolates were also γ-hemolytic and tolerant to various pH (pH 3, 5 and 7.5) and 0.3% (w/v) bile salts. The bacteria isolates of strain L8 and L20 were susceptible to seven antibiotics tested except vancomycin and tetracycline whereas S1 was resistant to all antibiotics. Phenotypic tests revealed that both bacteria isolates of strain L8 and L20 were Bacillus megaterium while S1 was Pediococcus pentosaceus whereas 16S rRNA gene sequence analysis showed potential bacteria isolates of strain L8 and L20 belonged to the Lactobacillus plantarum (99% similarity) and S1 was characterized as Lactobacillus pentosus (100% similarity) respectively. Our present study showed that the probiotics of strain L8, L20 and S1 isolated from the fermented fish (Pekasam) exhibited the potential probiotic properties to be developed as biotherapeutic agents

Duplex PCR assay for the species-specific detection of the marine pathogen, vibrio alginolyticus, using dnaJ and ompK genes

Vibrio alginolyticus, is an important opportunistic pathogen for worldwide aquatic animals and marine environment. However, the microbiological methods like culture-based diagnosis and biochemical identification of V. alginolyticus is time consuming and unspecific. Thus, the aim of the study was to develop a duplex PCR assay for the species-specific identification of V. alginolyticus. To evaluate PCR specificity, this assay directed toward the ompK-virulence gene and dnaJ gene tested on six Vibrio species and three non- Vibrio species. Two specific bands with the expected sizes of 846 bp and 144 bp, respectively, were produced in isolates belong to V. alginolyticus and only one band were produced by others Vibrio species, 846 bp for ompK gene indicating a high specificity of duplex PCR assay. The sensitivity test of duplex PCR was detected by using different cells concentration of V. alginolyticus. The detecting capability of the duplex PCR from crude DNA was at 102 and 103 cells/mL. The sensitivity and efficacy of the assay were clarified using artificially infected Artemia and water culture which a clear PCR bands of 846 bp and 144 bp were generated from Artemia homogenates and water culture infected with V. alginolyticus. Our results showed that this newly developed duplex PCR would offer an accuracy and ideal tool for species-specific detection of V. alginolyticusin preventing disease outbreak in marine aquaculture

Implicit social cognition mediator for the development of Malaysian Career Factor Inventory (MYCFI)

Current and existing Career Factor Inventory (CFI) lacks the depth in sociocultural parameters and social psychological ‘imaginations’. Implicit social cognition may offer some pertinent viable understandings in career indecision, which has been one of the central research issues of counselling and psychology, especially in young adults who are in the midst of making critical life decisions. According to Schneider (1991; Bazerman & Tenbrussel, 1998), social cognition has become the dominant perspective in psychology. However, it is important to understand that the ‘dark matter; of the mind involves the implicit processes (Schacter, 1987; Amodio & Ratner, 2011). Malaysia’s economy had been growing enormously by investing heavily in education and technology. The Malaysia success has had a tremendous sociological impact that is rarely mentioned but highly meaningful to all Malaysians. This is indeed the driving force behind the career-mindedness of most young Malaysians whose career choice-making is often fraught with numerous challenges. Therefore, this study is premised in an effort to discover the career indecision’s phenomena among the potential graduates and students from the Institution of Higher Learning in Malaysia through the development of Malaysian Career Factor Inventory (My-CFI) with denomination of social psychological’ lenses as eigenvector mediators. It is argued that behaviour or at least some of the mediators can be influenced by implicit social cognition. Theory of Planned Behaviour is used as the underpinning theory, which is hypothesised to be understood and it should be viewed together with the Theory of Cognitive Dissonance. It is meant to give the fundamental understandings that acknowledge both social cognition and planned behaviour approaches. The predictability of the precision measurement of extrapolating intention before one commits to any behaviour is also discussed. Preliminary results are presented and analysed

Antigenicity analysis and molecular characterization of two outer membrane proteins of Vibrio alginolyticus strain VA2 as vaccine candidates in tiger grouper culture

Vibriosis is one of the most prevalent fish diseases caused by bacteria from the genus Vibrio. An effective method to counter Vibriosis is vaccination which increases the resistance of the immune system to subsequent pathogen infection. In this study, Vibrio alginolyticus strain VA2 isolated from infected tiger groupers was selected for determination of the antigenicity and molecular characterization of its Outer Membrane Proteins (OMPs). Protein profiling of OmpK and OmpW were evaluated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) while their antigenicity were tested by Western Blot. Results of the Western Blot assay revealed three antigenic OMP bands about 23, 31 and 34 kDa. Sequencing results showed that the full length of the target genes OmpK and OmpW of V. alginolyticus strain VA2 were 846 and 642 bp, respectively. Multiple alignment analysis showed that both regions of OmpK and OmpW were highly conserved among Vibrio species, thus are good candidates for vaccine development. Phylogenetic analysis of OmpK and OmpW showed that most branches in which they were grouped with had bootstrap values higher than 50%, indicating high confidence level of the branches. The antigenic sites of OmpK and OmpW proteins were predicted which were 34 and 27, respectively, thus are good candidates for vaccine development

A snapshot study on larval fish diversity in selected mangrove areas of Peninsular Malaysia, Malaysia / Izzati Adilah Azmir... [et al.]

The study on composition, abundance and diversity of larval fish was conducted with the aim to attain information on larval fish breeding ground and made easy for fishery management. Larval fish were collected during September 2015 from mangrove areas of Pekan Pahang, Pendas Johor, Matang Perak and Setiu Terengganu using a bongo net, towed at a depth of about 0.5 m from the surface for 5 min against the tidal flow. A total of 354 larval fish were collected, representing 21 families and 51 species. The top 3 families were Gobiidae (39.26%), Engraulidae (14.97%) and Clupeidae (14.40%), occurred in all sampling areas except in Setiu. The most abundant 11 species formed about 50% of all collected larval fish. Gobiidae spp. were the most abundant, making up 17.8% of the total catch, followed by Clupeidae spp. (12.7%), Engraulidae spp. (8.2%), Ambassis dusumieri (6.5%), Thryssa kammalensis (4.8%), Pseudogobius masago (both 4.8%), Sillaginidae spp. (4.2%), Ambassidae spp. (3.4%), Pseudogobius sp. (3.4%), Blenniidae spp. (2.8%), and Hemigobius hoevenii (2.5%). The highest diversity of larval fish was recorded for Pendas, Johor with Shannon Wiener index Hs = 2.699, and the lowest was Setiu, Terengganu (Hs = 0.832). The highest evenness index of larval fish species was recorded for Pekan, Pahang with Es = 0.815 and the lowest for Setiu Terengganu with Es = 0.465, indicating high single-species dominance. Species overlapping was the highest between Pendas and Setiu at 14.3%, and zero similarity of fish composition was recorded between Matang and Setiu according to Jaccard coefficient. Findings from surveillance of larval fish species provide valuable information for future biodiversity studies and allow better management of biodiversity resources in the mangrove ecosystem of Malaysia

Recombinant luteinizing hormone development to improve the reproductive performance of female Malaysia catfish, Hemibagrus nemurus (Valenciennes, 1840)

Gonadotropins (GTHs), follicle-stimulating hormone (FSH), and luteinizing hormone (LH) are the major regulators of gonadal development in fish. This study reported the production of recombinant LH (rLH) in Hemibagrus nemurus. A single-chain rLH from H. nemurus was cloned into pET-32 and expressed in Escherichia coli. A specific band at 45.4 kDa was detected; this band corresponded to the molecular size of fusion rLH. Immature female H. nemurus were divided into four different treatment groups. Each group received a single injection of either 1X PBS, 0.5 ml/kg Ovaprim, rLH50 μg/kg, or rLH150 μg/kg. Gonad histology revealed that the fish treated with rLH50 μg/kg, rLH150 μg/kg, and Ovaprim could induce oocyte maturation at 48h post injection (p.i.). The 17ᵝ-estradiol (E2) plasma level in fish treated with rLH50 μg/kg significantly increased after 12h p.i., and the level was sustained up to 24h p.i. The mRNA expression levels of GTH subunits also significantly increased in fish treated with rLH50 μg/kg after 48h p.i. Fish treated with Ovaprim showed significantly increased E2 plasma levels after 6h p.i., but this level decreased after 12h p.i. No significant increase was found among mRNA subunits in fish treated with Ovaprim after 48h p.i. Treatment with rLH150 μg/kg had a weak stimulatory effect on the E2 production and the mRNA transcript level of GTH subunits