The weaver ant Oecophylla smaragdina is an aggressive predator of other arthropods and has been employed as a biological control agent against many insect pests in plantations. Despite playing important roles in pest management, information about the microbiota of O. smaragdina is limited. In this work, a number of O. smaragdina colonies (n = 12) from Malaysia had been studied on their microbiome profile using Illumina 16S rRNA gene amplicon sequencing. We characterized the core microbiota associated with these O. smaragdina and investigated variation between colonies from different environments. Across all 12 samples, 97.8% of the sequences were assigned to eight bacterial families and most communities were dominated by families Acetobacteraceae and Lactobacillaceae. Comparison among colonies revealed predominance of Acetobacteraceae in O. smaragdina from forest areas but reduced abundance was observed in colonies from urban areas. In addition, our findings also revealed distinctive community composition in O. smaragdina showing little taxonomic overlap with previously reported ant microbiota. In summary, our work provides information regarding microbiome of O. smaragdina which is essential for establishing healthy colonies. This study also forms the basis for further study on microbiome of O. smaragdina from other regions.
The relationship of Atlantic salmon gastrointestinal (GI) tract bacteria to environmental factors, in particular water temperature within a commercial mariculture system, was investigated.
Two traditional fermented food 'tapai' (fermented tapioca) and 'tempoyak' (fermented durian flesh), chilli puree and fresh goat's milk were used as sources for the isolation of lactic acid bacteria (LAB). A total of 126 isolates were obtained and by sequential screening for catalase activity and Gram-staining, 55 were determined to be LAB out of which 16 were established to be homofermentative by the gel plug test. Seven isolates were identified by use of the API 50CHL kit and two lactobacilli strains and one lactococci strain were selected to study their growth and lactic acid production profiles in a time course experiment. The lactobacilli strains, both isolated from 'tapai', produced higher amounts of cells and lactic acid from glucose as compared to the lactococci strain isolated from fresh goat's milk.
Paralactobacillus selangorensis gen. nov., sp. nov. is described. This organism, isolated from a Malaysian food ingredient called chili bo, is an obligatory homofermentative, rod-shaped lactic acid bacterium. The G+C content is 46.1-46.2+/-0.3 mol%. Earlier 16S rRNA studies showed that this organism constitutes a new taxon distantly related to the Lactobacillus casei-Pediococcus group. A phenotypic description that distinguishes Paralactobacillus selangorensis from other genera of lactic acid bacteria is presented. The type strain of Paralactobacillus selangorensis is LMG 17710T.
This study aims to determine physio-chemical properties of tempoyak, characterise the various indigenous species of lactic acid bacteria (LAB) present at different stages of fermentation and also to determine the survival of selected foodborne pathogens in tempoyak. The predominant microorganisms present in tempoyak were LAB (8.88-10.42 log CFU/g). Fructobacillus durionis and Lactobacillus plantarum were the dominant members of LAB. Other LAB species detected for the first time in tempoyak were a fructophilic strain of Lactobacillus fructivorans, Leuconostoc dextranicum, Lactobacillus collinoides and Lactobacillus paracasei. Heterofermentative Leuconostoc mesenteroides and F. durionis were predominant in the initial stage of fermentation, and as fermentation proceeded, F. durionis remained predominant, but towards the end of fermentation, homofermentative Lb. plantarum became the predominant species. Lactic, acetic and propionic acids were present in concentrations ranging from 0.30 to 9.65, 0.51 to 7.14 and 3.90 to 7.31 mg/g, respectively. Genotyping showed a high degree of diversity among F. durionis and Lb. plantarum isolates, suggesting different sources of LAB. All tested Lb. plantarum and F. durionis (except for one isolate) isolates were multidrug resistant. Salmonella spp., Listeria monocytogenes and Staphylococcus aureus were not detected. However, survival study showed that these pathogens could survive up to 8-12 days. The results aiming at improving the quality and safety of tempoyak.
Red dragon fruit or red pitaya is rich in potassium, fiber, and antioxidants. Its nutritional properties and unique flesh color have made it an attractive raw material of various types of food products and beverages including fermented beverages or enzyme drinks. In this study, phenotypic and genotypic methods were used to confirm the identity of lactic acid bacteria (LAB) appeared in fermented red dragon fruit (Hylocereus polyrhizus) beverages. A total of 21 isolates of LAB were isolated and characterized. They belonged to the genus of Enterococcus based on their biochemical characteristics. The isolates can be clustered into two groups by using the randomly amplified polymorphic DNA method. Nucleotide sequencing and restriction fragment length polymorphism of the 16S rRNA region suggested that they were either Enterococcus faecalis or Enterococcus durans.