No abstract

Heating in honey processing can inhibit fermentation, crystallization, and the growth of microorganisms, such as bacteria. However, the effect of the honey heating process on the properties of honey and its antibacterial activity has not been further studied. Therefore, in this study, the properties of honey of both Apis and Trigona species from Bogor, Kalimantan, Sulawesi, Sumatra, and Lombok, were tested. The properties of honey, including water content, acidity, reducing sugar, 5-hydroxymethylfurfural (HMF), and diastase enzyme activity, were tested at heating temperatures 50, 70, and 90 °C. The antibacterial activity was determined using the disc method against Escherichia coli and Staphylococcus aureus. The results showed that the average water content and acidity values decreased after heating. However, the values met the SNI quality requirements with a water content value of < 22% and the acidity value not exceeding 50 mL NaOH 0.1 N/kg in the Apis and Trigona types of honey. The reduced sugar content fluctuated after heating all samples, and the average HMF level of honey increased after heating. However, the activity of the diastase enzyme decreased, although the value was still within the SNI standard value. The selected honey samples of the Apis and Trigona types were active in inhibiting the growth of Staphylococcus aureus but were not active against Escherichia coli.

Enteropathogenic Escherichia coli (EPEC) is a Gram-negative pathogenic bacterium that causes diarrheal disease, especially in infants and children. Aptamers are short chain oligonucleotides that have high affinity, specificity, and selectivity to their targets, which have potential to be developed as a method for diagnosing pathogens. In this study, aptamer was isolated through the Systematic Evolution of Ligands by Exponential Enrichment (SELEX) method using whole cells bacteria (Bacterial-SELEX) for recognizing pathogenic E. coli EPEC K1.1 which was isolated from children with diarrhea in Indonesia. Ten rounds of bacterial-SELEX procedure were conducted with modification conditions by using Top10, DH5a E. coli cells, Listeria monocytogenes, and Lactobacillus plantarum S34 as counter-selections. The selection process was started with a pool of ssDNA random library consisting of a random base with 40-nucleotides long flanked with fixed primers sequence for aptamer amplification purpose. Short single-stranded DNA amplification was done by symmetric and asymmetric PCR. The highly enriched oligonucleotide pools (pooled 8, 9, and 10) were cloned and the resulting ssDNA aptamers were identified by Sanger DNA sequencing. Finally, twelve aptamers with unique sequences and various secondary structures including G-quadruplex sequence motif within aptamers were obtained as candidates specific aptamer for detection and capturing of EPEC K1.1.