Ageing and the gut-brain axis: lessons from the Drosophila model.

The steady decline of physiological function and increased vulnerability to age-related disorders are two features of the complicated biological process of ageing. As a key organ for nutrient absorption, metabolism, and immunological regulation, the gut plays a major part in the ageing process. Drosophila melanogaster, a well-established model organism, has emerged as a significant tool for exploring the intricate rapport between the gut and ageing. Through the use of Drosophila models, the physiological and molecular elements of the gut-brain axis have been thoroughly explored. These models have also provided insights into the mechanisms by which gut health impacts ageing and age-related illnesses. Drosophila's gut microbiota experience dysbiosis with age which has been linked to age-related diseases. To prevent this and promote healthy ageing in Drosophila, gut microbiota modification methods, such as dietary restriction in tandem with time-restricted feeding, administration of pro-, pre- and synbiotics, as well as pharmaceutical interventions have been generated with positive impacts. The article also covers the drawbacks and difficulties of investigating the gut via the Drosophila. Thus, with an emphasis on the lessons discovered from Drosophila research, this review provides an extensive description of the current studies on the role of the gut-brain axis in ageing and health.

Lactic acid bacteria feeding reversed the malformed eye structures and ameliorated gut microbiota profiles of Drosophila melanogaster Alzheimer's disease model.

AIMS: To utilize transgenic GMR-Aß42 Drosophila melanogaster as a model to evaluate potential Alzheimer's disease (AD)-reversal effects via the administration of lactic acid bacteria (LAB) strains, and associations of LAB with changes in gut microbiota profiles. METHODS AND RESULTS: Wild-type flies (Oregon-R) were crossed with glass multimer reporter-GAL4 (GMR-GAL4) to produce GMR-OreR (Control), while UAS-Aß42 (#33769) were crossed with GMR-GAL4 to produce transgenic Drosophila line that expressed Aß42 (GMR-Aß42). Feed containing seven different LAB strains (Lactobacillus paracasei 0291, Lactobacillus helveticus 1515, Lactobacillus reuteri 30242, L. reuteri 8513d, Lactobacillus fermentum 8312, Lactobacillus casei Y, Lactobacillus sakei Probio65) were given to GMR-Aß42 respectively, while feed without LAB strains were given to control and transgenic GMR-Aß42.nf Drosophila lines. The morphology of the eyes was viewed with scanning electron microscopy (SEM). The changes in gut microbiota profiles associated with LAB were analysed using 16s high throughput sequencing. Malformation of eye structures in transgenic GMR-Aß42 Drosophila were reversed upon the administration of LAB strains, with more prevalent effects from L. sakei Probio65 and L. paracasei 0291. The GMR-Aß42.nf group showed dominance of Wolbachia in the gut, a genus that was almost absent in the normal control group (P < 0·05). The administration of L. sakei Probio65 and L. paracasei 0291 reduced the abundance of Wolbachia accompanied by increased abundance of Stenotrophomonas and Acetobacter (P < 0·05), resembling the microbial profile of the control group. CONCLUSIONS: Lactobacillus sakei Probio65 and Lactobacillus paracasei 0291 have more prominent effects in reversing malformed eye of transgenic GMR-Aß42 Drosophila, and reducing the abundance of Wolbachia accompanied by an increased abundance of Stenotrophomonas and Acetobacter. SIGNIFICANCE AND IMPACT OF THE STUDY: Potentials of LAB to prevent and/or alleviate the onset and pathogenesis of neurodegenerative diseases such as AD, supporting brain health strategies along the gut-brain axis.

Recombinant turnip yellow mosaic virus coat protein as a potential nanocarrier.

AIMS: To display a short peptide (GSRSHHHHHH) at the C-terminal end of turnip yellow mosaic virus coat protein (TYMVc) and to study its assembly into virus-like particles (TYMVcHis6 VLPs). METHODS AND RESULTS: In this study, recombinant TYMVcHis6 expressed in Escherichia coli self-assembled into VLPs of approximately 30-32 nm. SDS-PAGE and Western blot analysis of protein fractions from the immobilized metal affinity chromatography (IMAC) showed that TYMVcHis6 VLPs interacted strongly with nickel ligands in IMAC column, suggesting that the fusion peptide is protruding out from the surface of VLPs. These VLPs are highly stable over a wide pH range from 3·0 to 11·0 at different temperatures. At pH 11·0, specifically, the VLPs remained intact up to 75°C. Additionally, the disassembly and reassembly of TYMVcHis6 VLPs were studied in vitro. Dynamic light scattering and transmission electron microscopy analysis revealed that TYMVcHis6 VLPs were dissociated by 7 mol l-1 urea and 2 mol l-1 guanidine hydrochloride (GdnHCl) without impairing their reassembly property. CONCLUSIONS: A 10-residue peptide was successfully displayed on the surface of TYMVcHis6 VLPs. This chimera demonstrated high stability under extreme thermal conditions with varying pH and was able to dissociate and reassociate into VLPs by chemical denaturants. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first C-terminally modified TYMVc produced in E. coli. The C-terminal tail which is exposed on the surface can be exploited as a useful site to display multiple copies of functional ligands. The ability of the chimeric VLPs to self-assemble after undergo chemical denaturation indicates its potential role to serve as a nanocarrier for use in targeted drug delivery.

Bone health among older persons in medical clinic: A clinical audit.

Osteoporosis is commonly underdiagnosed and undertreated. We performed a clinical audit to assess the risk factors and clinical care for osteoporosis among older persons who attended medical clinic during a 4-week period in August 2013. There was a total of 128 patients with a mean age of 73.1±5.8 years, and 20.3%. had a history of fall. Fracture Risk Assessment Tool (FRAX) scores assessment showed 14.2% and 68.8% had a 10-year risk of major osteoporotic and hip fractures respectively. Only 6.3% underwent Dual-energy X-ray absorptiometry (DXA) and 73.4% did not receive any preventive treatment for osteoporosis. Older persons attending medical clinic at high risk of osteoporosis fractures did not receive appropriate screening and treatment. There is a need to improve the suboptimal care for bone health among older persons.

Lactobacillus probiotics improved the gut microbiota profile of a Drosophila melanogaster Alzheimer's disease model and alleviated neurodegeneration in the eye.

Alzheimer's disease (AD) is a progressive disease and one of the most common forms of neurodegenerative disorders. Emerging evidence is supporting the use of various strategies that modulate gut microbiota to exert neurological and psychological changes. This includes the utilisation of probiotics as a natural and dietary intervention for brain health. Here, we showed the potential AD-reversal effects of Lactobacillus probiotics through feeding to our Drosophila melanogaster AD model. The administration of Lactobacillus strains was able to rescue the rough eye phenotype (REP) seen in AD-induced Drosophila, with a more prominent effect observed upon the administration of Lactobacillus plantarum DR7 (DR7). Furthermore, we analysed the gut microbiota of the AD-induced Drosophila and found elevated levels of Wolbachia. The administration of DR7 restored the gut microbiota diversity of AD-induced Drosophila with a significant reduction in Wolbachia's relative abundance, accompanied by an increase of Stenotrophomonas and Acetobacter. Through functional predictive analyses, Wolbachia was predicted to be positively correlated with neurodegenerative disorders, such as Parkinson's, Huntington's and Alzheimer's diseases, while Stenotrophomonas was negatively correlated with these neurodegenerative disorders. Altogether, our data exhibited DR7's ability to ameliorate the AD effects in our AD-induced Drosophila. Thus, we propose that Wolbachia be used as a potential biomarker for AD.