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Microbial fuel cell (MFC), a bio-electrochemical device that exploits electroactive microbes, has gained more attention in developing countries, such as Indonesia. Unfortunately, studies related to bio-electrochemistry are often constrained due to the need for precise and high-cost instrumentation, such as data logger/acquisition or data logging-multimeter for continuously monitoring electricity generation of MFCs in the rigid time interval. This present work aimed at two issues: (1) to evaluate the use of a low-cost microcontroller-based data logger, the developed multi-channels Arduino UNO-based data logging system, for monitoring the electricity generation of ten MFC bioreactors simultaneously, and (2) to evaluate the electrochemical performance of MFCs biocatalysts by ten electroactive microbes isolated from aquaculture pond sediment in Indonesia. The monitoring system worked with a multi-channels Arduino UNO, a multiplexer, an external 16-bit ADC (analogue to digital converter) ADS1115, and a RTC (real time clock) module. The MFC performance was evaluated in the terms of open circuit voltage and close circuit voltage (polarization curve, power density, and losses). Statistical analysis confirmed the high accuracy of the developed system with the average of absolute and relative error values of 1.21 mV and 1.26%, respectively, comparable to traditional multimeter utilized for MFC electricity measurement. These results suggested that the developed data logging system could be a considerable option as a low-cost monitoring device for electrochemical studies of MFCs. Electrochemical performances of ten anodic biocatalysts were also evaluated, suggesting that there were three effective bacteria (isolate KCf2, KCf4, and KCf10) for producing relatively stable bioelectricity in the reactor of MFCs. These three electroactive microbes can produce power density of 0.069 W m−2, 0.021 W m−2, and 0.010 W m−2, respectively. [ABSTRACT FROM AUTHOR]

Candidiasis has become increasingly widespread in the community alongside with the developing resistance of Candida sp. to some antifungals. A prevalence study in the present research is required to surveil the distribution of Candida-related infections to administrate the appropriate antifungal treatments. The objective of this research was to determine the species distribution of candidiasis with their antifungal susceptibility isolated from clinical specimens at the Zainoel Abidin Hospital (ZAH) Banda Aceh, Indonesia. The clinical specimens were from inpatients and outpatients in the hospital during January to June 2019. The identification of Candida species and antifungal sensitivity assay were conducted by using VITEK® 2 Compact. Of a total of 68 isolates, there were six species of Candida with the highest species prevalence was Candida tropicalis (52.94%). Additionally, the highest prevalence of candidiasis came from urine specimen (54.41%) and mostly from inpatients in the internal medicine unit (54.41%). Candidiasis occurred predominantly in men (58.82%) and during adulthood (55.88%). The antibiogram of Candida sp. shows a high percentage of sensitivity towards some antifungals including fluconazole (100%), voriconazole (100%), caspofungin (100%), micafungin (100%), amphotericin B (99.5%), and flucytosine (100%). From this result, it can be concluded that candidiasis cases in the ZAH Banda Aceh, Indonesia has prevalently occurred with the few antifungal therapies for candidiasis of were still effective empirically and definitively. This is an initial study of Candida prevalence within different clinical samples in Banda Aceh and the study is expected to be a basis for prevention and control of Candida-related infections in the area. [ABSTRACT FROM AUTHOR]

The virulence gene expression of phytopathogenic bacteria, such as Dickeya dadantii is regulated by quorum sensing (QS) mechanism. The QS mechanism is induced by acyl homoserine lactone (AHL) that is universal autoinducer of Gram-negative bacteria. Degradation of AHL compound can be used to control the virulence of phytopathogenic bacteria. The enzyme of AHL lactonase is encoded by the aiiA gene and can degrade the lactone ring of AHL. This study was aimed to characterize aiiA gene encoding AHL lactonase from 20 isolates of shrimp pond and soil forest, Indonesia and examine the isolates ability to reduce violacein pigment of Chromobacterium violaceum and soft rot disease symptoms caused by D. dadantii. The results showed nine bacterial isolates (B4, B10, B11, B13, B14, B16, B17, B18 and B19) containing the aiiA gene encoding AHL lactonase. Based on 16S rRNA gene identification, 9 isolates had the highest similarity with Bacillus toyonensis, B. cereus, B. thuringiensis, B. mycoides and B. subtilis. These isolates had the capability to reduce the formation of violacein pigment and the symptoms of soft rot disease in potatoes. These results show that the AHL lactonase produced by these isolates can be used as Quorum Quenching (QQ) agent to inhibit the QS mechanism [ABSTRACT FROM AUTHOR]

Rice blast is the main disease of rice plants in Indonesia and several countries worldwide. Controlling this disease using chemical fungicides has harmful effects on the environment. Therefore, we need biocontrol agents which are more environmentally friendly such as rice phyllosphere bacteria. This study aimed to explore bacteria producing bioactive compounds from the rice phyllosphere environment to control blast disease. A total of 88 isolates were successfully isolated from rice leaves in Sukabumi, Situgede, and Jasinga (West Java, Indonesia). From them, we obtained 22 bacteria isolates with antifungal activity against Pyricularia oryzae in vitro assay. In addition, seven non-pathogenic bacteria were obtained from further screening in hypersensitivity, hemolysis and pathogenicity assays, namely STGG 3, STGG 7, STGG 8, STGG 14, SKBV 1, STGV 8, and SKBG 78. To show their antifungal activity, we tested crude extracts of these seven isolates and the results revealed that all the crude extracts can inhibit the growth of P. oryzae. Based on a genetic approach, isolates STGG 3, STGG 7, and STGG 14 were found to have both nonribosomal peptide synthetases (NRPS) and polyketide synthases (PKS) genes, while isolate SKBV 1 only had the NRPS gene. The NRPS and PKS genes from potential isolates were similar to NRPS and PKS genes of Bacillus sp. in different strains. Furthermore, molecular identification based on the 16S rRNA gene revealed that the seven potential isolates belong to three genera, i.e. Bacillus (STGG 3, STGG 7, STGG 8, STGG 14, SKBV 1), Enterobacter (STGV 8) and Brachybacterium (SKBG 78). We suggest that the seven isolates found in this study have potency and could be recommended as biocontrol agents of blast disease caused by P. oryzae. [ABSTRACT FROM AUTHOR]

Alterations in the use of land for oil palm plantations can change the domination and activity of soil bacteria. More specifically, alteration in soil microbial communities can directly affect soil ecosystem functioning, particularly with respect to carbon and nitrogen cycles. Nitrogen can be a limiting nutrient, and the availability of nitrogen in the soil environment becomes a major factor in controlling the production of biomass. This research project aimed at studying the abundance of nitrogen-fixing, nitrogen-oxidizing, nitrogen-reducing, and ammonifying bacteria based on their functional genes in the tropical rain forests of Taman Nasional Bukit Duabelas (TNBD) and the oil palm plantations in Sarolangun Jambi. Samples were collected in November 2015. Soil sampling was performed randomly at three points representing each area of the tropical rainforests of TNBD and the seven- to eight-year-old oil palm plantations. Soil samples were collected using a soil sample core from 0-15 cm below the surface with depth strata of 0-5 cm, 5-10 cm, and 10-15 cm. Composite assessment was conducted on samples from each point corresponding to each respective depth strata. Soil samples were stored at -20°C prior to testing. Microbial abundance was measured using the most probable number (MPN) method. The abundance of microbes that play a role in nitrogen metabolism between strata of 5-10 cm and 10-15 cm does not appear to be different. The highest abundance of microbes in oil palm plantation land in Jambi was found in samples with nitrifying bacteria, later followed by denitrifying, nitrogen-fixing, and ammonifying bacteria. Ultimately, it was found that microbial abundance in oil palm plantations was higher than the corresponding rates in samples from tropical rainforests. [ABSTRACT FROM AUTHOR]

The research was conducted to study the metagenomic of actinomycetes based on 16S ribosomal RNA (rRNA) and bacterial nifH genes in soil and roots of four rice cultivars. The denaturing gradient gel electrophoresis profile based on 16S rRNA gene showed that the diversity of actinomycetes in roots was higher than soil samples. The profile also showed that the diversity of actinomycetes was similar in four varieties of rice plant and three types of agroecosystem. The profile was partially sequenced and compared to GenBank database indicating their identity with closely related microbes. The blast results showed that 17 bands were closely related ranging from 93% to 100% of maximum identity with five genera of actinomycetes, which is Geodermatophilus, Actinokineospora, Actinoplanes, Streptomyces and Kocuria. Our study found that Streptomyces species in soil and roots of rice plants were more varied than other genera, with a dominance of Streptomyces alboniger and Streptomyces acidiscabies in almost all the samples. Bacterial community analyses based on nifH gene denaturing gradient gel electrophoresis showed that diversity of bacteria in soils which have nifH gene was higher than that in rice plant roots. The profile also showed that the diversity of those bacteria was similar in four varieties of rice plant and three types of agroecosystem. Five bands were closely related with nifH gene from uncultured bacterium clone J50, uncultured bacterium clone clod-38, and uncultured bacterium clone BG2.37 with maximum identity 99%, 98%, and 92%, respectively. The diversity analysis based on 16S rRNA gene differed from nifH gene and may not correlate with each other. The findings indicated the diversity of actinomycetes and several bacterial genomes analyzed here have an ability to fix nitrogen in soil and roots of rice plant. [ABSTRACT FROM AUTHOR]