-
Angewandte Chemie (International Ed. in... Jun 2024Understanding the properties of the precursor can provide deeper insight into the crystallization and nucleation mechanisms of perovskites, which is vital for the...
Understanding the properties of the precursor can provide deeper insight into the crystallization and nucleation mechanisms of perovskites, which is vital for the solution-process device performance. In this work, we conducted a detailed investigation into the photophysics properties of all-inorganic perovskite (CsPbBr₃) precursors in a broad concentration and various solvents. The precursor gradually transformed from the solution state into the colloidal state and exhibited aggregation-induced emission (AIE) character as the concentration increased. The aggregative luminescence from the precursors originates from the polybromide plumbous that is formed through the coordination of solvent molecules to the lead metal center. Two adducts with monodentate (PbBr₂⋅solvent) and bidentate (PbB₂⋅2solvent) ligands can be obtained based on the coordination capability, accompanied by a red and green emission with photoluminescence peak at 610 and 565 nm, respectively. Furthermore, the aggregative luminescence intensity and color could be regulated by changing the solvent and precursor ratio. Besides, we discussed the difference between the molecular aggregate in the organic system and the ionic aggregate in the inorganic system. The fluorescence that is sensitive to Pb²⁺ coordination reported here could be applied to screen perovskite additives and judge the precursor aging.
PubMed: 38853460
DOI: 10.1002/anie.202408586 -
Developmental Biology Dec 2018Melanocytes derive from neural crest cells, which are a highly migratory population of cells that play an important role in pigmentation of the skin and epidermal...
Melanocytes derive from neural crest cells, which are a highly migratory population of cells that play an important role in pigmentation of the skin and epidermal appendages. In most vertebrates, melanocyte precursor cells migrate solely along the dorsolateral pathway to populate the skin. However, zebrafish melanocyte precursors also migrate along the ventromedial pathway, in route to the yolk, where they interact with other neural crest derivative populations. Here, we demonstrate the requirement for zebrafish paralogs pcdh10a and pcdh10b in zebrafish melanocyte precursor migration. pcdh10a and pcdh10b are expressed in a subset of melanocyte precursor and somatic cells respectively, and knockdown and TALEN mediated gene disruption of pcdh10a results in aberrant migration of melanocyte precursors resulting in fully melanized melanocytes that differentiate precociously in the ventromedial pathway. Live cell imaging analysis demonstrates that loss of pchd10a results in a reduction of directed cell migration of melanocyte precursors, caused by both increased adhesion and a loss of cell-cell contact with other migratory neural crest cells. Also, we determined that the paralog pcdh10b is upregulated and can compensate for the genetic loss of pcdh10a. Disruption of pcdh10b alone by CRISPR mutagenesis results in somite defects, while the loss of both paralogs results in enhanced migratory melanocyte precursor phenotype and embryonic lethality. These results reveal a novel role for pcdh10a and pcdh10b in zebrafish melanocyte precursor migration and suggest that pcdh10 paralogs potentially interact for proper transient migration along the ventromedial pathway.
Topics: Animals; Cadherins; Cell Differentiation; Cell Movement; Melanocytes; Neural Crest; Pigmentation; Protocadherins; Skin; Zebrafish; Zebrafish Proteins
PubMed: 29604249
DOI: 10.1016/j.ydbio.2018.03.022 -
Frontiers in Plant Science 2017Tocochromanols are organic compounds mostly produced by photosynthetic organisms that exhibit vitamin E activity in animals. They result from the condensation of... (Review)
Review
Tocochromanols are organic compounds mostly produced by photosynthetic organisms that exhibit vitamin E activity in animals. They result from the condensation of homogentisate with four different polyprenyl side chains derived all from geranylgeranyl pyrophosphate. The core tocochromanol biosynthesis has been investigated in several photosynthetic organisms and is now well-characterized. In contrast, our current knowledge of the biosynthesis and transport of tocochromanol biosynthetic precursors is much more limited. While tocochromanol synthesis occurs in plastids, converging genetic data in Arabidopsis and soybean demonstrate that the synthesis of the polar precursor homogentisate is located in the cytoplasm. These data implies that tocochromanol synthesis involves several plastidic membrane transporter(s) that remain to be identified. In addition, the metabolic origin of the lipophilic isoprenoid precursor is not fully elucidated. While some genetic data exclusively attribute the synthesis of the prenyl component of tocochromanols to the plastidic methyl erythritol phosphate pathway, multiple lines of evidence provided by feeding experiments and metabolic engineering studies indicate that it might partially originate from the cytoplasmic mevalonate pathway. Although this question is still open, these data demonstrate the existence of membrane transporter(s) capable of importing cytosolic polyprenyl pyrophosphate such as farnesyl pyrophosphate into plastids. Since the availability of both homogentisate and polyprenyl pyrophosphates are currently accepted as major mechanisms controlling the type and amount of tocochromanols produced in plant tissues, we summarized our current knowledge and research gaps concerning the biosynthesis, metabolic origins and transport of tocochromanol biosynthetic precursors in plant cells.
PubMed: 29184568
DOI: 10.3389/fpls.2017.01959 -
Molecular & Cellular Proteomics : MCP Feb 2023Data-independent acquisition (DIA) methods have become increasingly popular in mass spectrometry-based proteomics because they enable continuous acquisition of fragment...
Data-independent acquisition (DIA) methods have become increasingly popular in mass spectrometry-based proteomics because they enable continuous acquisition of fragment spectra for all precursors simultaneously. However, these advantages come with the challenge of correctly reconstructing the precursor-fragment relationships in these highly convoluted spectra for reliable identification and quantification. Here, we introduce a scan mode for the combination of trapped ion mobility spectrometry with parallel accumulation-serial fragmentation (PASEF) that seamlessly and continuously follows the natural shape of the ion cloud in ion mobility and peptide precursor mass dimensions. Termed synchro-PASEF, it increases the detected fragment ion current several-fold at sub-second cycle times. Consecutive quadrupole selection windows move synchronously through the mass and ion mobility range. In this process, the quadrupole slices through the peptide precursors, which separates fragment ion signals of each precursor into adjacent synchro-PASEF scans. This precisely defines precursor-fragment relationships in ion mobility and mass dimensions and effectively deconvolutes the DIA fragment space. Importantly, the partitioned parts of the fragment ion transitions provide a further dimension of specificity via a lock-and-key mechanism. This is also advantageous for quantification, where signals from interfering precursors in the DIA selection window do not affect all partitions of the fragment ion, allowing to retain only the specific parts for quantification. Overall, we establish the defining features of synchro-PASEF and explore its potential for proteomic analyses.
Topics: Tandem Mass Spectrometry; Proteomics; Proteome; Peptides
PubMed: 36566012
DOI: 10.1016/j.mcpro.2022.100489 -
Current Opinion in Structural Biology Apr 2018The small subunit processome is the first precursor of the small eukaryotic ribosomal subunit. During its assembly in the nucleolus, many ribosome biogenesis factors, an... (Review)
Review
The small subunit processome is the first precursor of the small eukaryotic ribosomal subunit. During its assembly in the nucleolus, many ribosome biogenesis factors, an RNA chaperone, and ribosomal proteins associate with the nascent pre-rRNA. Biochemical studies have elucidated the rRNA-subdomain dependent recruitment of these factors during SSU processome assembly and have been complemented by structural studies of the assembled particle. Ribosome biogenesis factors encapsulate and guide subdomains of pre-ribosomal RNA in distinct compartments. This prevents uncoordinated maturation and enables processing of regions not accessible in the mature subunit. By sequentially reducing conformational freedom, flexible proteins facilitate the incorporation of dynamic subcomplexes into a globular particle. Large rearrangements within the SSU processome are required for compaction into the mature small ribosomal subunit.
Topics: Animals; Humans; Models, Molecular; Nucleic Acid Conformation; Protein Conformation; RNA Precursors; RNA, Ribosomal; Ribosomal Proteins; Ribosome Subunits, Small
PubMed: 29414516
DOI: 10.1016/j.sbi.2018.01.008 -
Water Research Apr 2023Both quantifiable and semi-quantifiable poly- and perfluoroalkyl substances (PFAS) were evaluated in the influent, effluent, and biosolids of 38 wastewater treatment...
Both quantifiable and semi-quantifiable poly- and perfluoroalkyl substances (PFAS) were evaluated in the influent, effluent, and biosolids of 38 wastewater treatment plants. PFAS were detected in all streams at all facilities. For the means of the sums of detected, quantifiable PFAS concentrations were 98 ± 28 ng/L, 80 ± 24 ng/L, and 160,000 ± 46,000 ng/kg (dry weight basis) in the influent, effluent, and biosolids (respectively). In the aqueous influent and effluent streams this quantifiable PFAS mass was typically associated with perfluoroalkyl acids (PFAAs). In contrast, quantifiable PFAS in the biosolids were primarily polyfluoroalkyl substances that potentially serve as precursors to the more recalcitrant PFAAs. Results of the total oxidizable precursor (TOP) assay on select influent and effluent samples showed that semi-quantified (or, unidentified) precursors accounted for a substantial portion (21 to 88%) of the fluorine mass compared to that associated with quantified PFAS, and that this fluorine precursor mass was not appreciably transformed to perfluoroalkyl acids within the WWTPs, as influent and effluent precursor concentrations via the TOP assay were statistically identical. Evaluation of semi-quantified PFAS, consistent with results of the TOP assay, showed the presence of several classes of precursors in the influent, effluent, and biosolids; perfluorophosphonic acids (PFPAs) and fluorotelomer phosphate diesters (di-PAPs) occurred in 100 and 92% of biosolid samples, respectively. Analysis of mass flows showed that, for both quantified (on a fluorine mass basis) and semi-quantified PFAS, the majority of PFAS exited WWTPs through the aqueous effluent compared to the biosolids stream. Overall, these results highlight the importance of semi-quantified PFAS precursors in WWTPs, and the need to further understand the impacts of their ultimate fate in the environment.
Topics: Water Pollutants, Chemical; Biosolids; Fluorine; Fluorocarbons; Water Purification; Water
PubMed: 36801573
DOI: 10.1016/j.watres.2023.119724 -
Pharmacological Research Mar 2016Brain-derived neurotrophic factor (BDNF) is one of the most active members of the neurotrophin family. BDNF not only regulates neuronal survival and differentiation, but... (Review)
Review
Brain-derived neurotrophic factor (BDNF) is one of the most active members of the neurotrophin family. BDNF not only regulates neuronal survival and differentiation, but also functions in activity-dependent plasticity processes such as long-term potentiation (LTP), long-term depression (LTD), learning, and memory. Like other growth factors, BDNF is produced by molecular and cellular mechanisms including transcription and translation, and functions as a bioactive molecule in the nervous system. Among these mechanisms, a particular post-translational mechanism, namely the conversion of precursor BDNF into mature BDNF by proteolytic cleavage, was not fully understood. In this review, we discuss the manner through which this post-translational mechanism alters the biological actions of BDNF protein. In addition to the initially elucidated findings on BDNF, the biological roles of precursor BDNF and the BDNF pro-peptide, especially synaptic plasticity, will be extensively discussed. Recent findings on the BDNF pro-peptide will provide new insights for understanding the mechanisms of action of the pro-peptides of growth factors.
Topics: Animals; Brain-Derived Neurotrophic Factor; Humans; Long-Term Synaptic Depression; Neuronal Plasticity; Polymorphism, Genetic; Protein Precursors; Protein Processing, Post-Translational; Signal Transduction; Synapses; Synaptic Transmission
PubMed: 26747403
DOI: 10.1016/j.phrs.2015.12.019 -
Critical Reviews in Food Science and... Jul 2023Natural animal-based flavors have great appeal to consumers and have broad applications in the food industry. In this review, we summarized findings related to bacon and... (Review)
Review
Natural animal-based flavors have great appeal to consumers and have broad applications in the food industry. In this review, we summarized findings related to bacon and Cheddar cheese flavors' components and their precursors, reaction mechanisms, influential factors, and characterization methods. The results show that free sugars, free amino acids, peptides, vitamins, lipids, and nitrites are precursors to bacon flavor. The conditions governing the formation of bacon flavor are thermally dependent, which facilitates the use of thermal food processing to generate such a flavor. For Cheddar cheese flavor, milk ingredients such as lactose, citrate, fat, and casein are reported as precursors. The optimum conditions to generate Cheddar cheese flavor from precursors are quite strict, which limits its application in food processing. As an alternative, it is more practical to generate Cheddar cheese flavor by combining key aroma compounds using thermal food processing. This review provides the food industry the comprehensive information about the generation of bacon and Cheddar cheese flavors using precursor molecules.
PubMed: 37431669
DOI: 10.1080/10408398.2023.2230497 -
Journal of Agricultural and Food... Mar 2018Pioneering investigations into precursors of fruity and floral flavors established the importance of terpenoid and C-norisoprenoid glycosides to the flavor of aromatic... (Review)
Review
Pioneering investigations into precursors of fruity and floral flavors established the importance of terpenoid and C-norisoprenoid glycosides to the flavor of aromatic wines. Nowadays flavor precursors in grapes and wine are known to be structurally diverse, encompassing glycosides, amino acid conjugates, odorless volatiles, hydroxycinnamic acids, and many others. Flavor precursors mainly originate in the grape berry but also from oak or other materials involved in winemaking. Flavors are released from precursors during crushing and subsequent production steps by enzymatic and nonenzymatic transformations, via microbial glycosidases, esterases, C-S lyases, and decarboxylases, and through acid-catalyzed hydrolysis and chemical rearrangements. Flavors can also be liberated from glycosides and amino acid conjugates by oral microbiota. Hence, it is increasingly likely that flavor precursors contribute to retronasal aroma formation through in-mouth release during consumption, prompting a shift in focus from identifying aroma precursors in grapes to understanding aroma precursors present in bottled wine.
Topics: Fermentation; Flavoring Agents; Fruit; Humans; Microbiota; Taste; Vitis; Wine
PubMed: 28220693
DOI: 10.1021/acs.jafc.6b05255 -
Trends in Pharmacological Sciences Dec 2021RNA splicing, the process by which precursor mRNA (pre-mRNA) is processed to mature mRNA, is catalyzed by the spliceosome. Recently, Chatrikhi et al. identified...
RNA splicing, the process by which precursor mRNA (pre-mRNA) is processed to mature mRNA, is catalyzed by the spliceosome. Recently, Chatrikhi et al. identified pharmacologic means to perturb splicing by enhancing the spliceosome's binding to pre-mRNA. This represents a novel chemical target and mechanism for therapeutic modulation of splicing.
Topics: Humans; Mutation; RNA Precursors; RNA Splicing Factors; RNA, Messenger; Spliceosomes
PubMed: 34602305
DOI: 10.1016/j.tips.2021.09.006