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Methods in Enzymology 2024Terpenes constitute one of the largest family of natural products with potent applications as renewable platform chemicals and medicines. The low activity, selectivity...
Terpenes constitute one of the largest family of natural products with potent applications as renewable platform chemicals and medicines. The low activity, selectivity and stability displayed by terpene biosynthetic machineries can constitute an obstacle towards achieving expedient biosynthesis of terpenoids in processes that adhere to the 12 principles of green chemistry. Accordingly, engineering of terpene synthase enzymes is a prerequisite for industrial biotechnology applications, but obstructed by their complex catalysis that depend on reactive carbocationic intermediates that are prone to undergo bifurcation mechanisms. Rational redesign of terpene synthases can be tedious and requires high-resolution structural information, which is not always available. Furthermore, it has proven difficult to link sequence space of terpene synthase enzymes to specific product profiles. Herein, the author shows how ancestral sequence reconstruction (ASR) can favorably be used as a protein engineering tool in the redesign of terpene synthases without the need of a structure, and without excessive screening. A detailed workflow of ASR is presented along with associated limitations, with a focus on applying this methodology on terpene synthases. From selected examples of both class I and II enzymes, the author advocates that ancestral terpene cyclases constitute valuable assets to shed light on terpene-synthase catalysis and in enabling accelerated biosynthesis.
Topics: Alkyl and Aryl Transferases; Terpenes; Protein Engineering; Evolution, Molecular
PubMed: 38942509
DOI: 10.1016/bs.mie.2024.04.025 -
Korean Journal of Radiology Jul 2024
Topics: Humans; Pulmonary Artery; Iatrogenic Disease; Enbucrilate; Male; Embolization, Therapeutic; Female; Middle Aged
PubMed: 38942462
DOI: 10.3348/kjr.2024.0311 -
International Journal of Biological... Jun 2024Alzheimer's disease (AD) is a neurodegenerative disorder marked by cognitive impairment and memory loss. In this study, AD was experimentally induced in rats using...
Fisetin-loaded pluronic-based nanogel: Radiation synthesis for alleviating neurocognitive impairments in a rat model of alzheimer's disease via modulation of the apoptotic cascade.
Alzheimer's disease (AD) is a neurodegenerative disorder marked by cognitive impairment and memory loss. In this study, AD was experimentally induced in rats using aluminum chloride (AlCl) and D-galactose (D-gal). Fisetin (Fis), a natural compound with antioxidant and anti-inflammatory properties, has potential for neurodegeneration management, but its low bioavailability limits clinical applications. To address this, we synthesized and characterized Pluronic-2-Acrylamido-2-methylpropane sulfonic acid (PLUR-PAMPS) nanogels using gamma radiation and successfully loaded Fis onto them (Fis-PLUR-PAMPS). The optimal formulation exhibited minimal particle size, a highly acceptable polydispersity index, and the highest zeta-potential, enhancing stability and solubilization efficiency. Our goal was to improve Fis's bioavailability and assess its efficacy against AlCl/D-gal-induced AD. Male albino Wistar rats were pre-treated orally with Fis (40 mg/kg) or Fis-PLUR-PAMPS for seven days, followed by a seven-day intraperitoneal injection of AlCl and D-gal. Behavioral assessments, histopathological analysis, and biochemical evaluation of markers related to AD pathology were conducted. Results demonstrated that Fis-PLUR-PAMPS effectively mitigated cognitive impairments and neurodegenerative signs induced by AlCl/D-gal. These findings suggest that Fis-PLUR-PAMPS nanogels enhance Fis's bioavailability and therapeutic efficacy, offering a promising approach for AD management.
PubMed: 38942410
DOI: 10.1016/j.ijbiomac.2024.133472 -
International Journal of Biological... Jun 2024This study investigates the conversion of highly acetylated sugarcane bagasse into high-modulus carbon nanofibers (CnNFs) with exceptional electrical conductivity. By...
This study investigates the conversion of highly acetylated sugarcane bagasse into high-modulus carbon nanofibers (CnNFs) with exceptional electrical conductivity. By electrospinning the bagasse into nanofibers with diameters ranging from 80 nm to 800 nm, a cost-effective CnNFs precursor is obtained. The study reveals the transformation of the cellulose crystalline structure into a stable antiparallel chain arrangement of cellulose II following prolonged isothermal treatment, leading to a remarkable 50 % increase in CnNFs recovery with carbon contents ranging from 80 % to 90 %. This surpasses the performance of any other reported biomass precursors. Furthermore, graphitization-induced shrinkage of CnNFs diameter results in significant growth of specific surface area and pore volume in the resulting samples. This, along with a highly ordered nanostructure and high crystallinity degree, contributes to an impressive tensile modulus of 9.592 GPa, surpassing that of most petroleum-based CnNFs documented in the literature. Additionally, the prolonged isothermal treatment influences the d002 value (measured at 0.414 nm) and CnNFs degree of crystallinity, leading to an enhancement in electrical conductivity. However, the study observes no size effect advantages on mechanical properties and electrical conductivity, possibly attributed to the potential presence of point defects in the ultrathin CnNFs. Overall, this research opens a promising and cost-effective pathway for converting sugarcane biomasses into high-modulus carbon nanofibers with outstanding electrical conductivity. These findings hold significant implications for the development of sustainable and high-performance materials for various applications, including electronics, energy storage, and composite reinforcement.
PubMed: 38942408
DOI: 10.1016/j.ijbiomac.2024.133480 -
The Science of the Total Environment Jun 2024Antarctica has traditionally been viewed as a relatively isolated ecosystem. Although still considered pristine, it is increasingly also being affected by microplastic...
Antarctica has traditionally been viewed as a relatively isolated ecosystem. Although still considered pristine, it is increasingly also being affected by microplastic pollution. Reported high sea floor concentrations raise concern that these ecosystems might act as major sink for microplastic pollution. This is significant as species in those remote ecosystems are likely more sensitive to rapid environmental change due to a high level of specialization, and lower tolerance levels. Microplastic ingestion in fish has barely been assessed in high latitude environments. Here we aimed to provide baseline data for the eastern Weddell Sea, which is particularly remote, and suggested for an area of conservation. By analyzing gastrointestinal tracts of 40 specimens from five species, we report an overall microplastic incidence rate of 0.23. This is lower than recent studies have found for other species in the Southern Ocean, and below global means. The highest incidence rate was detected in L. squamifrons (0.67), followed by P. evansii (0.29). The most common polymer was polyethylene recovered as 8 particles (42.1 %) from one specimen, while from the remaining 11 microplastics polyester was most common (36.8 %). This study shows that even in a remote region of the Antarctic Ocean with almost no vessel traffic, fisheries or touristic activity, bathydemersal and bathypelagic fish exhibit microplastic particles in their gastrointestinal tract.
PubMed: 38942313
DOI: 10.1016/j.scitotenv.2024.174320 -
The Science of the Total Environment Jun 2024Microplastics (MPs) have found extensive application globally due to their low cost, flexibility and light weight. Microplastic pollution is a growing environmental... (Review)
Review
Microplastics (MPs) have found extensive application globally due to their low cost, flexibility and light weight. Microplastic pollution is a growing environmental concern that poses significant threats to aquatic ecosystems worldwide, including African freshwater systems. Nevertheless, although Africa houses some of the deepest and largest freshwater rivers and lakes in the world such as Lake Tanganyika and Victoria, River Congo and the Nile, there is limited information available regarding the presence of MPs in these inland waters. Selected published data on MPs in African freshwater systems, including sediments, biota, rivers, and lakes, were incorporated in this review. The study discovered that the sampling technique employed has a major impact on the morphological characteristics and abundance of MPs in African freshwater systems. Fibers and fragments were the most common shapes; black, white, and transparent were the most prevalent colors; and polyethene terephthalate, polystyrene, and polypropylene were the frequently dominant polymers. As the distance between the sampling sites increased geographically, the polymer similarities declined. MPs have been found to translocate into body cells and tissues where they are capable of causing genetic mutations, cytotoxicity, oxidative stress and neurotoxicity. In Africa, MPs are poorly managed and monitored, and there has been insufficient research done on the possibility that they could be present in drinking water. Considering the fact that humans in the continent are exposed to freshwater and aquatic organisms, the risk assessment routes are currently unvalidated, therefore it was recommended that African nations should strengthen their capacity for plastic management and environmental monitoring. This review provides up to date information on the occurrence, prevalence, ecotoxicity and management of MPs across African freshwater systems.
PubMed: 38942312
DOI: 10.1016/j.scitotenv.2024.174092 -
The Science of the Total Environment Jun 2024Soil environments across the globe, particularly in agricultural settings, have now been shown to be contaminated with microplastics. Agricultural plastics - such as...
Soil environments across the globe, particularly in agricultural settings, have now been shown to be contaminated with microplastics. Agricultural plastics - such as mulching films - are used in close or direct contact with soils and there is growing evidence demonstrating that they represent a potential source of microplastics. There is a demand to undertake fate and effects studies to understand the behaviour and potential long-term ecological risks of this contamination. Yet, there is a lack of test materials available for this purpose. This study describes the manufacture and characterisation of five large (1-40 kg) batches of microplastic test materials derived from agricultural mulching films. Batches were produced from either polyethylene-based conventional mulching films or starch-polybutadiene adipate terephthalate blend mulching films that are certified biodegradable in soil. Challenges encountered and overcome during the micronisation process provide valuable insights into the future of microplastic test material generation from these material types. This includes difficulties in micronising virgin polyethylene film materials. All five batches were subjected to a thorough physical and chemical characterisation - both of the original virgin films and the subsequent microplastic particles generated - including a screening for the presence of chemical additives. This is a critical step to provide essential information for interpreting particle fate or effects in scientific testing. Trade-offs between obtaining preferred particle typologies and time and cost constraints are elucidated. Several recommendations emerging from the experiences gained in this study are put forward to advance the research field towards greater harmonisation and utilisation of environmentally relevant test materials.
PubMed: 38942306
DOI: 10.1016/j.scitotenv.2024.174325 -
Journal of Pharmaceutical Sciences Jun 2024This study aimed to investigate the impact of amorphous solubility and colloidal drug-rich droplets on drug absorption. The amorphous solubility of cilnidipine (CND) in...
This study aimed to investigate the impact of amorphous solubility and colloidal drug-rich droplets on drug absorption. The amorphous solubility of cilnidipine (CND) in AS-HF grade of hypromellose acetate succinate (HPMC-AS) solution was significantly reduced compared to that in non-polymer solution due to AS-HF partitioning into the CND-rich phase. In contrast, AS-LF grade of HPMC-AS has minimal effect on the amorphous solubility. The size of colloidal CND-rich droplets formed in the CND-supersaturated solution was less than 100 nm in the presence of AS-HF, while 200-450 nm in the presence of AS-LF. When the CND concentrations were near the amorphous solubility, CND membrane flux was reduced in the presence of AS-HF due to the decrease in the amorphous solubility of CND. However, the CND flux increased with the increase in CND-rich droplets, especially in the AS-HF solution. The size reduction of the CND-rich droplets led to their effective diffusion into the unstirred water layer, enhancing CND flux. In higher CND concentration regions, the CND flux became higher in the AS-HF solution than in the AS-LF solution. Thus, it is essential to elucidate the drug concentration-dependent impact of the colloidal drug-rich droplets on the drug absorption performance to optimize supersaturating formulations.
PubMed: 38942292
DOI: 10.1016/j.xphs.2024.06.017 -
Environmental Pollution (Barking, Essex... Jun 2024The microbial community colonized on microplastics (MPs), known as the 'plastisphere', has attracted extensive concern owing to its environmental implications. Coastal...
The microbial community colonized on microplastics (MPs), known as the 'plastisphere', has attracted extensive concern owing to its environmental implications. Coastal salt marshes, which are crucial ecological assets, are considered sinks for MPs. Despite their strong spatial heterogeneity, there is limited information on plastisphere across diverse environments in coastal salt marshes. Herein, a 1-year field experiment was conducted at three sites in the Yancheng salt marsh in China. This included two sites in the intertidal zone, bare flat (BF) and Spartina alterniflora vegetation area (SA), and one site in the supratidal zone, Phragmites australis vegetation area (PA). Petroleum-based MPs (polyethylene and expanded polystyrene) and bio-based MPs (polylactic acid and polybutylene succinate) were employed. The results revealed significant differences in bacterial community composition between the plastisphere and sediment at all three sites examined, and the species enriched in the plastisphere exhibited location-specific characteristics. Overall, the largest difference was observed at the SA site, whereas the smallest difference was observed at the BF site. Furthermore, the MP polymer types influenced the composition of the bacterial communities in the plastisphere, also exhibiting location-specific characteristics, with the most pronounced impact observed at the PA site and the least at the BF site. The polybutylene succinate plastisphere bacterial communities at the SA and PA sites were quite different from the plastispheres from the other three MP polymer types. Co-occurrence network analyses suggested that the bacterial community network in the BF plastisphere exhibited the highest complexity, whereas the network in the SA plastisphere showed relatively sparse interactions. Null model analyses underscored the predominant role of deterministic processes in shaping the assembly of plastisphere bacterial communities across all three sites, with a more pronounced influence observed in the intertidal zone than in the supratidal zone. This study enriches our understanding of the plastisphere in coastal salt marshes.
PubMed: 38942280
DOI: 10.1016/j.envpol.2024.124465 -
Environmental Research Jun 2024Microplastics (MPs) can enter the reproductive system and can be potentially harmful to human reproductive health. In this study, 13 types of microplastics (MPs) were...
Microplastics (MPs) can enter the reproductive system and can be potentially harmful to human reproductive health. In this study, 13 types of microplastics (MPs) were identified in patient blood, cancer samples, and paracarcinoma samples using Raman spectroscopy, with polyethylene, polypropylene and polyethylene-co-polypropylene being the most abundant polymer types. Futher, cotton was also found in our study. The diversity and abundance of MPs were higher in blood samples than in cancerous tissues, and there was a significant positive correlation between diversity (p < 0.05). Furthermore, the diversity and abundance of MPs in cancerous tissues were higher than in paracancerous tissues. The dimensional sizes of MPs in these samples were also very similar, with the majority of detected MPs being smaller in size. Correlation analysis showed that patient's age correlated with the abundance of MPs in blood samples, body mass index (BMI) correlated with the abundance of MPs in cancerous tissues. Notably, the frequency with which patients consume bottled water and beverages may also increase the abundance of MPs. This study identifies for the first time the presence of MPs and cotton in cancerous and paracancerous tissues of human cervical cancer patients. This provides new ideas and basic data to study the risk relationship between MP exposure and human health.
PubMed: 38942254
DOI: 10.1016/j.envres.2024.119498