Evaluation of different methods for the effective isolation of high-quality DNA from rodent faecal samples

Aims@#The inefficient lysis of recalcitrant bacterial cell wall and subsequent isolation of DNA from environmental samples can lead to a bias in the qualitative and quantitative assessment of bacteria present in the sample. Thus, the selection of an optimum DNA isolation method is the important first step for biosurveillance and metagenomic analyses. This study aims to determine the optimal DNA isolation method out of four commercial DNA isolation kits (A, B, C and D) and two conventional methods (E and F), for rodent faecal droppings. The key selection criterion is the general bacterial diversity contained in the isolated DNA, as evaluated by the Shannon-Weaver index based on the maximal number of PCR-amplicons of partial 16S rRNA gene, derived from each method. The amplicons were separated in accordance with their difference in nucleotide sequences via DGGE. @*Methodology and results@#Five faecal samples of wild rodents were collected from different sites and preserved in DNA/RNA shield reagent (Zymo Research). Each sample was extracted, and the DNA extracts were then subjected to amplification of the bacterial 16S rRNA and DGGE separation of the amplicons. Method E showed a higher yield of DNA (average 324.22 ng/µL) as compared to the other methods. However, the majority of the DNA extracts showed partial degradation. The DGGE profiles showed the highest number of amplicons were generated from DNA extracted from Method A and B with a total of 168 and 167 respectively. This is indicated by the Shannon-Weaver index which were 0.306 and 0.305, respectively. @*Conclusion, significance and impact of study@#Method A is the optimum DNA isolation method for rodent faecal samples as its isolated DNA contains the most diverse bacteria. The isolated DNA can then be used for PCR-biosurveillance or metagenomic sequencing and analyses.

Bioelectricity generation using banana peel as substrate in dual-chamber Pseudomonas aeruginosa based microbial fuel cell

Aims@#Banana peel (BP) waste is still underutilized in Malaysia, which can be used as source of renewable energy. Microbial fuel cell (MFC) is a device that utilizes biomass to convert chemical energy into electrical energy with help of the microbial catalysis. The present study evaluates the current generation of MFC supplemented with BP waste as substrate for Pseudomonas aeruginosa ATCC 27853.@*Methodology and results@#The CHNS result shows that the C:N ratio of BP is 27:1 which is within the optimum C:N ratio for the microbial food requirement. Fluctuation of current increases as concentration of banana peel extract (BPE) decreases from 1:10, 1:20, 1:40 and 1:80, thus making 1:10 BPE optimum. Current fluctuation is related to microbial activity due to the sufficiency of nutrients which subsequently affect the performance of MFC. BPE and banana peel slurry (BPS) comparison shows that BPS is optimum. BPE reaches a maximum current of 3.91 µA in ascending phase which is higher compared to BPS (3.65 µA). In descending phase, BPE current drops to 2.31 µA compared to 2.98 µA of BPS. In stationary phase, BPS able to maintain a higher current compared to BPE. MFC maximum current was doubled to 6.52 µA when PEM was treated priorly.@*Conclusion, significance and impact of study@#Besides exploring and improving the ability of MFC as an alternative for power production other than fossil fuel, this research also encourage society to fully utilize waste as a source of renewable energy instead of throwing it into garbage without productivity.

Optimizing electrochemical DNA biosensors for the detection of avian infectious bronchitis virus

Aims@#The aim of the study is to develop the optimised parameters of electrochemical DNA biosensors for the specific detection of the Infectious Bronchitis Virus (IBV) in chickens. The goal is to further create a highly sensitive and specific biosensor that can be used for on-site monitoring of IBV on poultry farms. @*Methodology and results@#In this study, an electrochemical DNA biosensor was developed for detecting a specific sequence in the IBV genome. The process involved attaching a NH2-ssDNA probe to a gold electrode, followed by hybridization with the target DNA. Various parameters like buffer, pH, scan rate, incubation time, redox indicators and temperature were optimised using cyclic voltammetry. The probe DNA was designed to enhance hybridization efficiency, which was assessed by measuring current signals. The biosensor, under optimal conditions, demonstrated high sensitivity and specificity when tested with different sequences, including complementary, non-complementary and mismatched ones. Cross-reactivity studies against non-IBV viruses showed distinguishable current signals. These findings have implications for developing a portable on-site IBV monitoring device for use on farms. @*Conclusion, significance and impact of study @#The optimised parameters and specificity of the electrochemical DNA biosensor suggest its potential for the development of a portable device for on-site monitoring of IBV on poultry farms. This device could prove to be a valuable tool for the early detection of IBV, helping to prevent further spread of the disease. However, it's essential to conduct further research to ensure the practicality and accuracy of the biosensor in real-world farm settings.

Comparative screening of anti-dengue activity in aqueous and ethanol extracts of mangrove plants from Sabah

Aims@#Dengue virus is a global pathogen that lacks an effective vaccine or therapy. Screening medicinal plants for anti-dengue properties provides a promising avenue to identify potent compounds. Mangroves, known for their resilience in harsh conditions, produce a diverse range of natural products with unique biochemical profiles, which hold potential for anti-dengue treatments. This study aims to evaluate the anti-dengue activity of selected mangrove plant species from Sabah against DENV2 NS2B-NS3pro, utilizing an enzymatic protease assay. @*Methodology and results @#Six mangrove species (Avicennia marina, Bruguiera gymnorrhiza, Ceriops tagal, Rhizophora apiculata, Rhizophora mucronata and Xylocarpus granatum) were investigated, with various plant parts subjected to aqueous and ethanol extraction. The results demonstrated significant anti-dengue activity in both aqueous and ethanolic extracts of the mangroves against DENV2 NS2B-NS3pro, with IC50 values ranging from 0.95 µg/mL to 6.24 µg/mL. Notably, the ethanolic extract of R. apiculata leaves exhibited the highest inhibition, with an IC50 value of 0.95 µg/mL. @*Conclusion, significance and impact of study@#These findings suggest that the ethanolic extracts from R. apiculata leaves hold promise as potential candidates for dengue treatment. This study underscores the importance of natural products as valuable sources for the development of novel anti-dengue treatments, highlighting the need to explore mangroves in the quest for effective therapeutic options.

Mycobacterium tuberculosis as a resilient foe in the mechanisms of colonisation, pathogenesis and host immune responses serves as a prerequisite for the development of potential mangrove plant-derived anti-TB drugs

@#Mycobacterium tuberculosis (MTB) is a highly adaptive pathogen that emerged as a devastating and mortality-related disease agent. The limited efficacy of the Mycobacterium bovis BCG vaccine, antibiotics and intensive treatment to prevent mortality have piqued researchers' interest in host-pathogen interactions. Besides the emergence of multi-drug resistant TB as a drawback, the host immune responses could be successfully subverted and exploited by the MTB-host pathogenesis during the early stages of innate immunity. Factors contributing to mycobacterial pathogenesis are concomitant and multifactorial, including virulence factors such as adhesins, toxins and enzymes that drive the progression of MTB infection. Initially, alveolar macrophage (AM), which has been considered to restrain bacterial growth, facilitates the spread of disease through interactions with MTB. The progression to bacterial replication and systemic infection before the initiation of cell-mediated immunity (CMI) indicates a delay in the activation of adaptive immunity, which is crucial. The findings are supported by the bacterial multiplication and dissemination in the infected alveolar macrophage in animal models. On the other hand, mangrove plants have revealed a structural diversity and a plethora of compounds responsible for antibacterial, antifungal and antiviral activities. These may serve as potential bioactive compounds for anti-TB drugs. In this review, we discuss mycobacterial colonisation, tissue invasion and host inflammatory responses that lead to the pathogenesis of MTB, along with the potential bioactive compounds for alternative plant-derived anti-TB drugs. The mechanistic insights provide significant discoveries on the limitations of immunity, offering important strategies for developing immunomodulating drugs.

Fin fish vaccination as prevention in aquaculture: A review

@#Fisheries and aquaculture are notably known as the most important sources of protein that can provide food for billions of people worldwide. The aquatic farming production keeps expanding gradually in recent years professing that fisheries and aquaculture has become the fastest growing food-producing market. This sector continues to attract great interest from everyone due to its promising contribution in global food security, economic and social development. However, growing high density of marine culture to maximize the production has caused the aquatic animals to be vulnerable to diseases. Various infectious fish diseases have led to high fish mortality that later poses a significant threat to companies’ long-term viability and countries’ socio-economic development. Therefore, this review discusses fish diseases and the overview of fish vaccines as one of the approaches to ensure a sustainable future for aquaculture.

Biofilm formation of serotype 19 Streptococcus pneumoniae clinical isolates in relation to clinical isolate source, pH and Fe(III) supplementation

Aims@#Streptococcus pneumoniae is one the world’s foremost bacterial pathogens that cause massive global mortality and morbidity in young children and immunocompromised adults especially in developing countries. Biofilms have been increasingly recognized as an important prerequisite to disease. Individual S. pneumoniae strains differ markedly in their virulence phenotypes, but genetic heterogeneity has complicated attempts to identify any association between a given clonal lineage and propensity to cause a particular disease type. This study investigated serotype 19 S. pneumoniae from blood and ear isolates for biofilm formation capacity in relation to isolate source, pH and ferric oxide [Fe(III)] supplementation.@*Methodology and results@#Viable count and density biofilm assays, microscopy and multi locus sequence typing (MLST) were applied to investigate biofilm formation capacity and genetic diversity of serotype 19 S. pneumoniae from blood and ear isolates. Generally, blood isolates were observed to produce more biofilms at both pH 7.4 and 6.8 compared to the ear isolates. The supplementation of Fe(III) was also found to support biofilm growth. Upon MLST typing of the isolates, marked differences in biofilm formation within the same sequence types (ST) of ST199 and ST177 was observed. This strongly indicated that strains within the same sequence type show differences in biofilm formation capacity.@*Conclusion, significance and impact of study@#This study showed that despite belonging to the same serotype, serotype 19, S. pneumoniae blood and ear isolates showed high diversity in biofilm formation ability in relation to pH and Fe(III) supplementation. Additionally, pneumococcal isolates from sequence types ST199 and ST177 also gave rise to differences in biofilm formation ability within the same sequence type (ST). The diversity of biofilm formation within serotype 19 seen in this study is significant to further inform of vaccination strategies against pneumococcal infections, in that due to variations in biofilm formation capacity within the same ST. It is possible that within serotype 19 may show variable vaccination or drug treatment responses. This also indicates that the current treatment strategy which employs specific serotype selection as for PCV14 and PCV7 pneumococcal vaccines may not produce the desired therapeutic results.