👤 Shiler Khaledi

Encapsulation of Lactiplantibacillus plantarum (L. plantarum) ZGP-Lpl.19 in alginate-pectin-chitosan microcapsules significantly improved its survival under simulated gastrointestinal conditions and attenuated Shigella flexneri (S. flexneri) growth and pathogenicity through downregulation of the mdoH and IcsA virulence genes. Microencapsulation was achieved via extrusion using a polysaccharide blend, yielding an encapsulation efficiency of 98.44%. Structural integrity of the microcapsules was confirmed by scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR). Encapsulation markedly enhanced probiotic survivability, with viable counts of 5.37 log CFU/mL after 60 min in gastric fluid and 120 min in intestinal fluid, compared with 2.25 log CFU/mL for free cells. Both encapsulated and free L. plantarum ZGP-Lpl.19 demonstrated potent antimicrobial activity against S. flexneri ATCC 12022, with comparable antimicrobial metabolite production. The minimum inhibitory concentration (MIC) of cell-free supernatants from both forms was 1/8 of the original concentration. Importantly, real-time PCR analysis confirmed that both encapsulated and free cells significantly downregulated mdoH and IcsA expression. Overall, these findings demonstrate that alginate-pectin-chitosan microencapsulation provides effective protection for L. plantarum and enhances its functional delivery, positioning encapsulated L. plantarum as a promising therapeutic strategy to mitigate S. flexneri infections. Show less

The accumulation of amyloid beta (Aβ) plaques and neurofibrillary tangles (NFTs) composed of Tau protein is two characteristic brain pathologies in Alzheimer's disease (AD). However, the Aβ hypothesis has recently faced challenges due to the limited clinical efficacy of anti-Aβ antibodies, such as aducanumab and lecanemab. This comprehensive review highlights recent advances and debates regarding the pathophysiology of Aβ peptides and plaques in AD, as well as their use as biomarkers and drug targets. Aβ aggregation is primarily driven by an imbalance between its generation from amyloid precursor protein (APP) and its clearance from the brain, processes influenced by various risk factors. The toxicity of amyloid plaques is affected by the accumulation of different Aβ species with varying lengths and post-translational modifications of Aβ. Additionally, pathways including neuroinflammation, blood-brain barrier deterioration, autophagy and mitochondrial dysfunction, lipid raft changes, and oxidative stress have pivotal roles in AD. Therefore, a clear map of Aβ's upstream regulators and downstream effectors is crucial for developing effective diagnostics and treatments for AD. Incorporating new research findings and ongoing debates surrounding the Aβ cascade hypothesis is crucial for improving early diagnosis and for guiding the development of effective treatments for AD. Show less