Biodegradation of polyvinyl chloride, polystyrene, and polylactic acid microplastics in Tenebrio molitor larvae: Physiological responses.

It is widely understood that microplastics (MPs) can induce various biological stresses in macroinvertebrates that are incapable of biodegrading plastics. However, the biodegradation and physiological responses of plastic-degrading macroinvertebrates toward MPs of different degradability levels remain unexplored. In this study, Tenebrio molitor larvae (mealworms) were selected as a model of plastics-degrading macroinvertebrate, and were tested against three common plastics of different degradability rankings: polyvinyl chloride (PVC), polystyrene (PS), and polylactic acid (PLA) MPs (size <300 µm). These three MPs were biodegraded with the rate sequence of PLA > PS > PVC, resulting in a reversed order of negative physiological responses (body weight loss, decreased survival, and biomass depletion) of mealworms. Simultaneously, the levels of reactive oxygen species (ROS), antioxidant enzyme activities, and lipid peroxidation were uniformly increased as polymer degradability decreased and intermediate toxicity increased. PVC MPs exhibited higher toxicity than the other two polymers. The oxidative stresses were effectively alleviated by supplementing co-diet bran. The T. molitor larvae fed with PLA plus bran showed sustainable growth without an increase in oxidative stress. The results provide new insights into the biotoxicity of MPs on macroinvertebrates and offer comprehensive information on the physiological stress responses of plastic-degrading macroinvertebrates during the biodegradation of plastics with different degradability levels.

Effects of microwave on extracellular vesicles and microRNA in milk.

This study demonstrates the effects of microwaves on the microRNA (miRNA) content of milk and milk extracellular vesicles (EV). We determined the miRNA concentration in milk subjected to different treatments using real-time PCR and a spectrophotometer. The miRNA expression and total RNA content of the microwaved milk samples were lower when compared with untreated milk. We measured the microstructure and the size distribution by scanning electron microscopy and dynamic light scattering to verify the loss of miRNA in microwaved milk due to damage to the EV. The results revealed that 2 different-sized EV were present and had an average size of 147.50 and 22.14 nm, respectively. Furthermore, acridine orange staining showed that the total RNA content in microwaved milk EV was lower than that in cow milk. These results suggest that EV may confer the protection and the stability of the miRNA in milk.

Synthesis and bioactivity of tripolinolate A from Tripolium vulgare and its analogs.

A new coniferol derivative, named as tripolinolate A (1), and 11 known compounds (2-12) were isolated from whole plants of Tripolium vulgare Nees. The structure of this new compound was determined as 4-(2S-methylbutyryl)-9-acetyl-coniferol based on its NMR and HRESIMS spectral analyses. A simple and efficient method was designed to prepare tripolinolate A and its 19 analogs including nine new chemical entities for bioactive assay. Tripolinolate A and its analog 4,9-diacetyl-coniferol were found to be the two most active compounds that significantly inhibited the proliferation of different cancer cell lines with IC50 values ranging from 0.36 to 12.9µM and induced apoptosis in tumor cells. Structure-activity relationship analysis suggested that the molecular size of acyl moieties at C-4 and C-9 position might have an effect on the activity of this type of coniferol derivatives.

Bioactive sulfated saponins from sea cucumber Holothuria moebii.

The bioactive ingredients of sea cucumber Holothuria moebii were investigated, and four sulfated saponins (1-4) and one desulfated saponin (3B) with an unusual 3,4-epoxy xylose were obtained from this study. Compound 2 is a new triterpenoid saponin and 3B is a new artificial compound. On the basis of the extensive NMR and HRESIMS data, their structures were assigned as 3-O-[ß-D-quinovopyranosyl-(1 → 2)-4-sodium sulfato-ß-D-xylopyranosyl]-25-acetoxy-22-oxo-9(11)-holostene-3ß,12α,17α-triol (2) and 3-O-[ß-D-quinovopyranosyl-(1 → 2)-3,4-epoxy-ß-xylopyranosyl]-22,25-epoxy-9(11)-holostene-3ß,12α,17α-triol (3B). Compounds 1-4 showed activity suppressing the proliferation of four different glioma cells with IC50 values ranging from 0.99 to 8.64 µM. New saponin 2 significantly induced apoptosis in human glioblastoma U87-MG cells and reduced the expression levels of several glioma metabolic enzymes of glycolysis and glutaminolysis. This study reveals for the first time that selectively targeting multiple glioma metabolic regulators of glycolysis and glutaminolysis might be one of the anti-glioma mechanisms of saponin 2.

Bioactive triterpenoid saponins and phenolic compounds against glioma cells.

A total of 54 natural origin compounds were evaluated for their activity in inhibiting the proliferation of glioma cells. Results showed that four Aesculus polyhydroxylated triterpenoid saponins (3-6), six Gleditsia triterpenoid saponins (7-12), and five phenolic compounds (43-46, 51) had dose-dependent activity suppressing the proliferation of both C6 and U251 cells. Structure-activity relationship analysis suggested that the acetyl group at C-28 for the Aesculus saponins and the monoterpenic acid moiety for the Gleditsia saponins could be critical for the activity of these active compounds. Aesculioside H (4), gleditsioside A (7), and feuric acid 3,4-dihydroxyphenethyl ester (FADPE, 46) were the three most active compounds from the different types of the active compounds and induced apoptosis and necrosis in glioma cells.

Fatsioside A, a rare baccharane-type glycoside inhibiting the growth of glioma cells from the fruits of Fatsia japonica.

A novel baccharane-type triterpenoid glycoside named fatsioside A (1), together with ten oleanane glycosides, were isolated from the fruits of Fatsia japonica. The structure of fatsioside A was assigned as 3ß,15α,18α-trihydroxy-18,19-secolupane-12,19-dione 3-O-ß-D-glucopyranosyl-(1 → 2)-ß-D-glucopyranoside by extensive NMR and HRESIMS analyses. F. japonica is the third baccharane glycoside-containing species reported to date in the plant kingdom, while fatsioside A represents the first baccharane glycoside found in the Araliaceae family. Fatsioside A inhibited the growth of rat glioma C6 cells and human glioma U251 cells with IC50 values of 33.48 ± 2.01 µM and 77.58 ± 6.19 µM, respectively. Further investigation indicated that fatsioside A induced apoptosis and necrosis in glioma cells, and arrested the cell cycle at the G0/G1 phase.

New capoamycin-type antibiotics and polyene acids from marine Streptomyces fradiae PTZ0025.

Capoamycin-type antibiotics (2-5) and polyene acids (6, 7) were isolated from marine Streptomyces fradiae strain PTZ0025. Their structures were established by extensive nuclear magnetic resonance (NMR) and high resolution electron spray ionization mass spectroscopy (HRESIMS) analyses and chemical degradation. Compounds 3, 4, 6, 7 were found to be new and named as fradimycins A (3) and B (4), and fradic acids A (6) and B (7). Compounds 3-5 showed in vitro antimicrobial activity against Staphylococcus aureus with a minimal inhibitory concentration (MIC) of 2.0 to 6.0 µg/mL. Interestingly, Compounds 3-5 also significantly inhibited cell growth of colon cancer and glioma with IC50 values ranging from 0.13 to 6.46 µM. Fradimycin B (4), the most active compound, was further determined to arrest cell cycle and induce apoptosis in tumor cells. The results indicated that fradimycin B (4) arrested the cell cycle at the G0/G1 phase and induced apoptosis and necrosis in colon cancer and glioma cells. Taken together, the results demonstrated that the marine natural products 3-5, particularly fradimycin B (4), possessed potent antimicrobial and antitumor activities.

Biological Functions and Cross-Kingdom Host Gene Regulation of Small RNAs in Lactobacillus plantarum-Derived Extracellular Vesicles.

Extracellular vesicle-mediated transfer of microRNAs is a novel mode of cell-to-cell genetic transmission. Extracellular vesicles produced by microbes have been shown to contain significant quantities of physiologically active molecules such as proteins, lipids, and RNA, which could be transported to host cells and play a key role in both inter-kingdom signaling and physiological responses. In this study, we identified sRNAs by sequencing small RNAs (sRNAs) from Lactobacillus plantarum-derived extracellular vesicles (LDEVs) and detected the expression levels of vesicular sRNAs using quantitative reverse transcription-polymerase chain reaction (RT-PCR), which demonstrated the presence of microRNA-sized RNAs (msRNAs) within these vesicles. We chose sRNA71, a highly expressed msRNA, for further investigation, predicted its potential target genes for the human genome, and indicated that it could be translocated into mammalian cells. The biological functions of this sRNA71 were subsequently explored through cellular proteomics, western blot, and luciferase reporter assay. According to the findings, transfection with synthetic sRNA71 mimics substantially reduced Tp53 expression in HEK293T cells and suppressed the gene expression through binding to the 3' UTR of Tp53 mRNA. In conclusion, it is hypothesized that microbial-derived extracellular vesicles serve as carriers of functional molecules such as sRNAs, which play an essential role in regulating microbial-host communication.

Characterization of three different types of extracellular vesicles and their impact on bacterial growth.

Recently body fluids have been found to contain a class of nanoparticles released from cells, referred to as extracellular vesicles; exosomes are a type of small-diameter extracellular vesicle. We selected three types of sample: milk-derived exosomes, adipose-derived stem cell exosomes, and nanoparticles extracted from coconut water, to investigate their morphology, particle size distribution, protein content, and microRNA expression levels. Among the vesicles investigated, coconut nanoparticles had the greatest size distribution, and the protein content of coconut nanoparticles differed from that of mammalian exosomes. Using fluorescence microscopy, we determined that DiI-labeled extracellular vesicles could be absorbed by bacteria. Prominently, milk-derived exosomes could promote the growth of Escherichia coli K-12 MG1655 and Lactobacillus plantarum WCFS1. The studied extracellular vesicles could alter bacterial gene expression. Overall, this study identified differences in exogenous extracellular vesicles from different sources and revealed their supportive effects on microbial growth to make better utilization of microbial resources.

Isolation of Exosome-Like Nanoparticles and Analysis of MicroRNAs Derived from Coconut Water Based on Small RNA High-Throughput Sequencing.

In this study, the presence of microRNAs in coconut water was identified by real-time polymerase chain reaction (PCR) based on the results of high-throughput small RNA sequencing. In addition, the differences in microRNA content between immature and mature coconut water were compared. A total of 47 known microRNAs belonging to 25 families and 14 new microRNAs were identified in coconut endosperm. Through analysis using a target gene prediction software, potential microRNA target genes were identified in the human genome. Real-time PCR showed that the level of most microRNAs was higher in mature coconut water than in immature coconut water. Then, exosome-like nanoparticles were isolated from coconut water. After ultracentrifugation, some particle structures were seen in coconut water samples using 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate fluorescence staining. Subsequent scanning electron microscopy observation and dynamic light scattering analysis also revealed some exosome-like nanoparticles in coconut water, and the mean diameters of the particles detected by the two methods were 13.16 and 59.72 nm, respectively. In conclusion, there are extracellular microRNAs in coconut water, and their levels are higher in mature coconut water than in immature coconut water. Some exosome-like nanoparticles were isolated from coconut water, and the diameter of these particles was smaller than that of animal-derived exosomes.