5-Hydroxymethylfurfural and its Downstream Chemicals: A Review of Catalytic Routes.

Biomass assumes an increasingly vital role in the realm of renewable energy and sustainable development due to its abundant availability, renewability, and minimal environmental impact. Within this context, 5-hydroxymethylfurfural (HMF), derived from sugar dehydration, stands out as a critical bio-derived product. It serves as a pivotal multifunctional platform compound, integral in synthesizing various vital chemicals, including furan-based polymers, fine chemicals, and biofuels. The high reactivity of HMF, attributed to its highly active aldehyde, hydroxyl, and furan ring, underscores the challenge of selectively regulating its conversion to obtain the desired products. This review highlights the research progress on efficient catalytic systems for HMF synthesis, oxidation, reduction, and etherification. Additionally, it outlines the techno-economic analysis (TEA) and prospective research directions for the production of furan-based chemicals. Despite significant progress in catalysis research, and certain process routes demonstrating substantial economics, with key indicators surpassing petroleum-based products, a gap persists between fundamental research and large-scale industrialization. This is due to the lack of comprehensive engineering research on bio-based chemicals, making the commercialization process a distant goal. These findings provide valuable insights for further development of this field.

A Mettl16/m6A/mybl2b/Igf2bp1 axis ensures cell cycle progression of embryonic hematopoietic stem and progenitor cells.

Prenatal lethality associated with mouse knockout of Mettl16, a recently identified RNA N6-methyladenosine (m6A) methyltransferase, has hampered characterization of the essential role of METTL16-mediated RNA m6A modification in early embryonic development. Here, using cross-species single-cell RNA sequencing analysis, we found that during early embryonic development, METTL16 is more highly expressed in vertebrate hematopoietic stem and progenitor cells (HSPCs) than other methyltransferases. In Mettl16-deficient zebrafish, proliferation capacity of embryonic HSPCs is compromised due to G1/S cell cycle arrest, an effect whose rescue requires Mettl16 with intact methyltransferase activity. We further identify the cell-cycle transcription factor mybl2b as a directly regulated by Mettl16-mediated m6A modification. Mettl16 deficiency resulted in the destabilization of mybl2b mRNA, likely due to lost binding by the m6A reader Igf2bp1 in vivo. Moreover, we found that the METTL16-m6A-MYBL2-IGF2BP1 axis controlling G1/S progression is conserved in humans. Collectively, our findings elucidate the critical function of METTL16-mediated m6A modification in HSPC cell cycle progression during early embryonic development.

The splicing factor Prpf31 is required for hematopoietic stem and progenitor cell expansion during zebrafish embryogenesis.

Pre-mRNA splicing is a precise regulated process and is crucial for system development and homeostasis maintenance. Mutations in spliceosomal components have been found in various hematopoietic malignancies (HMs) and have been considered as oncogenic derivers of HMs. However, the role of spliceosomal components in normal and malignant hematopoiesis remains largely unknown. Pre-mRNA processing factor 31 (PRPF31) is a constitutive spliceosomal component, which mutations are associated with autosomal dominant retinitis pigmentosa. PRPF31 was found to be mutated in several HMs, but the function of PRPF31 in normal hematopoiesis has not been explored. In our previous study, we generated a prpf31 knockout (KO) zebrafish line and reported that Prpf31 regulates the survival and differentiation of retinal progenitor cells by modulating the alternative splicing of genes involved in mitosis and DNA repair. In this study, by using the prpf31 KO zebrafish line, we discovered that prpf31 KO zebrafish exhibited severe defects in hematopoietic stem and progenitor cell (HSPC) expansion and its sequentially differentiated lineages. Immunofluorescence results showed that Prpf31-deficient HSPCs underwent malformed mitosis and M phase arrest during HSPC expansion. Transcriptome analysis and experimental validations revealed that Prpf31 deficiency extensively perturbed the alternative splicing of mitosis-related genes. Collectively, our findings elucidate a previously undescribed role for Prpf31 in HSPC expansion, through regulating the alternative splicing of mitosis-related genes.

The splicing factor DHX38 enables retinal development through safeguarding genome integrity.

DEAH-Box Helicase 38 (DHX38) is a pre-mRNA splicing factor and also a disease-causing gene of autosomal recessive retinitis pigmentosa (arRP). The role of DHX38 in the development and maintenance of the retina remains largely unknown. In this study, by using the dhx38 knockout zebrafish model, we demonstrated that Dhx38 deficiency causes severe differentiation defects and apoptosis of retinal progenitor cells (RPCs) through disrupted mitosis and increased DNA damage. Furthermore, we found a significant accumulation of R-loops in the dhx38-deficient RPCs and human cell lines. Finally, we found that DNA replication stress is the prerequisite for R-loop-induced DNA damage in the DHX38 knockdown cells. Taken together, our study demonstrates a necessary role of DHX38 in the development of retina and reveals a DHX38/R-loop/replication stress/DNA damage regulatory axis that is relatively independent of the known functions of DHX38 in mitosis control.

Tulp1 deficiency causes early-onset retinal degeneration through affecting ciliogenesis and activating ferroptosis in zebrafish.

Mutations in TUB-like protein 1 (TULP1) are associated with severe early-onset retinal degeneration in humans. However, the pathogenesis remains largely unknown. There are two homologous genes of TULP1 in zebrafish, namely tulp1a and tulp1b. Here, we generated the single knockout (tulp1a-/- and tulp1b-/-) and double knockout (tulp1-dKO) models in zebrafish. Knockout of tulp1a resulted in the mislocalization of UV cone opsins and the degeneration of UV cones specifically, while knockout of tulp1b resulted in mislocalization of rod opsins and rod-cone degeneration. In the tulp1-dKO zebrafish, mislocalization of opsins was present in all types of photoreceptors, and severe degeneration was observed at a very early age, mimicking the clinical manifestations of TULP1 patients. Photoreceptor cilium length was significantly reduced in the tulp1-dKO retinas. RNA-seq analysis showed that the expression of tektin2 (tekt2), a ciliary and flagellar microtubule structural component, was downregulated in the tulp1-dKO zebrafish. Dual-luciferase reporter assay suggested that Tulp1a and Tulp1b transcriptionally activate the promoter of tekt2. In addition, ferroptosis might be activated in the tulp1-dKO zebrafish, as suggested by the up-regulation of genes related to the ferroptosis pathway, the shrinkage of mitochondria, reduction or disappearance of mitochondria cristae, and the iron and lipid droplet deposition in the retina of tulp1-dKO zebrafish. In conclusion, our study establishes an appropriate zebrafish model for TULP1-associated retinal degeneration and proposes that loss of TULP1 causes defects in cilia structure and opsin trafficking through the downregulation of tekt2, which further increases the death of photoreceptors via ferroptosis. These findings offer insight into the pathogenesis and clinical treatment of early-onset retinal degeneration.

Accumulation of Lipid Droplets in a Novel Bietti Crystalline Dystrophy Zebrafish Model With Impaired PPARα Pathway.

Purpose: Bietti crystalline dystrophy (BCD) is a progressive retinal degenerative disease primarily characterized by numerous crystal-like deposits and degeneration of retinal pigment epithelium (RPE) and photoreceptor cells. CYP4V2 (cytochrome P450 family 4 subfamily V member 2) is currently the only disease-causing gene for BCD. We aimed to generate a zebrafish model to explore the functional role of CYP4V2 in the development of BCD and identify potential therapeutic targets for future studies. Methods: The cyp4v7 and cyp4v8 (homologous genes of CYP4V2) knockout zebrafish lines were generated by CRISPR/Cas9 technology. The morphology of photoreceptor and RPE cells and the accumulation of lipid droplets in RPE cells were investigated at a series of different developmental stages through histological analysis, immunofluorescence, and lipid staining. Transcriptome analysis was performed to investigate the changes in gene expression of RPE cells during the progression of BCD. Results: Progressive retinal degeneration including RPE atrophy and photoreceptor loss was observed in the mutant zebrafish as early as seven months after fertilization. We also observed the excessive accumulation of lipid droplets in RPE cells from three months after fertilization, which preceded the retinal degeneration by several months. Transcriptome analysis suggested that multiple metabolism pathways, especially the lipid metabolism pathways, were significantly changed in RPE cells. The down-regulation of the peroxisome proliferator-activated receptor α (PPARα) pathway was further confirmed in the mutant zebrafish and CYP4V2-knockdown human RPE-1 cells. Conclusions: Our work established an animal model that recapitulates the symptoms of BCD patients and revealed that abnormal lipid metabolism in RPE cells, probably caused by dysregulation of the PPARα pathway, might be the main and direct consequence of CYP4V2 deficiency. These findings will deepen our understanding of the pathogenesis of BCD and provide potential therapeutic approaches.

Efficient Etherification of 2,5-Bis(hydroxymethyl)furan to 2,5-Bis(propoxymethyl)furan by an Amorphous Silica-Alumina Catalyst in a Fixed-Bed Reactor.

The efficient etherification of 2,5-bis(hydroxymethyl)furan (BHMF) to 2,5-bis(propoxymethyl)furan (BPMF) was achieved by using low-cost amorphous silica-aluminas (ASA) catalysts in a fixed-bed reactor. A considerable yield of BPMF up to 85.1 % was obtained over ASA-30 catalyst under the reaction conditions of 140 °C, 2.0 MPa of N2 , and 0.015 h-1 of WHSV. The excellent performance of ASA-30 catalyst could be attributed to the relatively stronger acidity (>375 °C) and larger mesoporous size (6 nm), thereby facilitating the conversion of BHMF to BPMF. In addition, the lower ratio of Brønsted/Lewis acid sites for ASA catalyst was found to efficiently suppress the occurrence of side reactions.

Knockout of mafba Causes Inner-Ear Developmental Defects in Zebrafish via the Impairment of Proliferation and Differentiation of Ionocyte Progenitor Cells.

Zebrafish is an excellent model for exploring the development of the inner ear. Its inner ear has similar functions to that of humans, specifically in the maintenance of hearing and balance. Mafba is a component of the Maf transcription factor family. It participates in multiple biological processes, but its role in inner-ear development remains poorly understood. In this study, we constructed a mafba knockout (mafba-/-) zebrafish model using CRISPR/Cas9 technology. The mafba-/- mutant inner ear displayed severe impairments, such as enlarged otocysts, smaller or absent otoliths, and insensitivity to sound stimulation. The proliferation of p63+ epidermal stem cells and dlc+ ionocyte progenitors was inhibited in mafba-/- mutants. Moreover, the results showed that mafba deletion induces the apoptosis of differentiated K+-ATPase-rich (NR) cells and H+-ATPase-rich (HR) cells. The activation of p53 apoptosis and G0/G1 cell cycle arrest resulted from DNA damage in the inner-ear region, providing a mechanism to account for the inner ear deficiencies. The loss of homeostasis resulting from disorders of ionocyte progenitors resulted in structural defects in the inner ear and, consequently, loss of hearing. In conclusion, the present study elucidated the function of ionic channel homeostasis and inner-ear development using a zebrafish Mafba model and clarified the possible physiological roles.

Comparison of bacterial communities between midgut and midgut contents in two silkworms, Antheraea pernyi and Bombyx mori.

Bacterial communities living inside the midgut of insects have been attracting increasing interest. Previous studies have shown that both the midgut and midgut contents harbor bacterial communities. However, whether the bacterial communities of the insect midgut are similar to those of the insect midgut contents (including the peritrophic membrane, food particles, and digestive fluids secreted by the midgut in this study) remains unknown. In the present study, we analyzed two economically important silkworms, the Chinese oak silkworm Antheraea pernyi (Lepidoptera: Saturniidae) and the mulberry silkworm Bombyx mori (Lepidoptera: Bombycidae), through Illumina MiSeq technology to address this issue. In A. pernyi larvae, 17 phyla and 162 genera were found in the midgut, while 7 phyla and 36 genera were found in the midgut contents. For B. mori larvae, 30 phyla and 465 genera were found in the midgut, but 22 phyla and 344 genera were found in the midgut contents. This evidence from the two silkworms suggests that the bacterial composition and diversity in the midgut are more diverse than those in the midgut contents. Principal component analysis revealed a significant difference in the bacterial community structure between the midgut and midgut contents of B. mori. To our knowledge, this is the first study to compare the bacterial communities between the midgut and midgut contents in insects, and the results will provide useful information for probing the functional differentiation within the midgut in the future.

A high level of chloroplast genome sequence variability in the Sawtooth Oak Quercus acutissima.

The Sawtooth Oak, Quercus acutissima Carruth., is an economically and ecologically important tree species in the family Fagaceae with a wide distribution in China. Here, we examined its intraspecific chloroplast (cp) genome variability using available and a newly sequenced genome. The new cp genome comes from a Q. acutissima individual collected from Shenyang (Northeast China; "Q. acutissima Shenyang" in the following), and then is compared with two recently published cp genomes from Tongchuan (Northwest China) and Nanjing (East China). The cp genome of Q. acutissima Shenyang exhibits a slightly larger genome size than the other two individuals, although each encodes 86 protein-coding genes, 40 tRNA genes and eight rRNA genes. We also found the length difference for the IR/SC boundary region among the three cp genomes. Sequence comparison revealed a high intraspecific genetic divergence: the three cp genomes differ by 332 sequence patterns including 77 single nucleotide polymorphisms, and 255 indels (each gap considered) scattering across 67 regions. Phylogenetic analyses based on the cp genome recovered the split between the subgenus Cerris and the subgenus Quercus, but revealed that three Q. acutissima individuals did not cluster together, indicating that even complete cp genome data fail to reproduce species boundaries in Asian members of section Cerris. Our results show that more complete plastomes covering remote ranges needs to be sequenced to provide a solid backbone for future population-scale in-depth studies and phylogenetic analysis of section Cerris.

Efficient production of 5-hydroxymethylfurfural from fructose over CuAPO-5 molecular sieves synthesized using an ionothermal method.

A group of CuAPO-5 molecular sieves with trace Cu were successfully synthesized via an ionothermal method and used for fructose dehydration to 5-hydroxymethylfurfural (HMF) in [BMIM]Br ionic liquid. The 0.06-CuAPO-5 sample displayed excellent performance and a HMF yield of 93.8% was obtained, which could be ascribed to the balance between acid strength and mass transfer efficiency. This work demonstrates that the ionothermal synthesized CuAPO-5 molecular sieve was also a good candidate for the efficient production of HMF.

The complete chloroplast genome sequence of Salix viminalis (Salicaceae).

Here, the complete chloroplast (cp) genome of Salix viminalis was reported. The genome is 155,531 bp long, with a GC content of 36.71%, and contains four sub-regions: 84,395 bp of large single copy (LSC) and 16,218 bp of small single copy (SSC) regions, separated by 27,459 bp of inverted repeat (IR) regions. A total of 129 genes were annotated, including 83 protein-coding genes, 38 tRNA genes, and 8 rRNA genes. The Phylogenetic analyses based on the whole cp genome sequence placed S. viminalis into a clade containing Salix rehderiana, Salix taoensis, Salix koriyanagi, and Salix suchowensis. This is the first complete cp genome for S. viminalis that would be useful for phylogenetic and population genetic studies of this species.

The complete chloroplast genome of Quercus fenchengensis and the phylogenetic implication.

Quercus fenchengsis is a rare Chinese oak species sporadically recorded in Fengcheng, Liaoning, Yuntai Mountain, Henan, and Qinling Mountains, Shaanxi. Here, the complete chloroplast (cp) genome of Q. fenchengensis was first reported. The cp genome is 161,296 bp in length with a GC content of 36.81%, and encodes 134 genes (86 protein-coding genes, 40 tRNA genes and eight rRNA genes). The phylogenetic tree based on the cp genome confirmed that Q. fenchengensis has a close relationship with Quercus aliena acutiserrata and Quercus dentata, consistent with the previous morphology-based suggestion that it would be a hybrid of Q. aliena acutiserrata and Q. dentata.

The complete chloroplast genome sequence of the threatened Cypripedium calceolus (Orchidaceae).

The complete chloroplast genome of Cypripedium calceolus, a rare species in the family Orchidaceae was reported in this study. The genome size is 175,122 bp in length, and contains four sub-regions: 97,486 bp of large single copy (LSC) and 22,260 bp of small copy (SSC) regions, separated by 27,688 bp of inverted repeat (IR) regions. A total of 133 genes were annotated, including 87 protein-coding genes, 38 tRNA genes and 8 rRNA genes. The GC content of this cp genome is 34.36%. Phylogenetic analysis revealed a close relationship between C. calceolus with C. japonicum and C. formosanum. This is the first complete cp genome for C. calceolus that would be useful for conservation and phylogenetic studies of this species.

The Complete Mitochondrial Genome of the Longhorn Beetle Dorysthenes paradoxus (Coleoptera: Cerambycidae: Prionini) and the Implication for the Phylogenetic Relationships of the Cerambycidae Species.

The longhorn beetle Dorysthenes paradoxus (Faldermann, 1833) (Coleoptera: Cerambycidae) is not only a serious agricultural pest but also a traditionally edible insect in China. However, no genetic information on this species has been acquired. In the present study, we report the mitochondrial genome (mitogenome) of Do. paradoxus, as the first complete mitogenome of Prioninae. The circular mitogenome of 15,922 bp encodes 13 protein-coding genes (PCGs), 22 transfer RNAs (tRNAs), and two ribosomal RNAs (rRNAs), and it contains an A+T-rich region. This mitogenome exhibits the lowest A+T content (71.13%) but harbors the largest AT skew (0.116) among the completely sequenced Cerambycidae species. Eleven of the 13 PCGs have a typical ATN start codon, whereas COI and ND1 are tentatively designated by AAT and TTG, respectively. Only 4 of the 13 PCGs harbor a complete termination codon, and the remaining 9 possess incomplete termination codons (T or TA). Apart from tRNASer(AGN), the other 21 tRNAs can fold into a typical clover-leaf secondary structures. The Do. paradoxus A+T-rich region contains two poly-T stretches and a tandem repeat that comprises two 47-bp-long copies. Both Bayesian inference and Maximum likelihood analyses confirmed the subfamily ranks of Cerambycidae ([Prioninae + Cerambycinae] + Lamiinae) and the close relationship between Philinae and Prioninae/Cerambycinae. However, the data did not support the monophyly of Prioninae and Cerambycinae. The mitogenome presented here provides basic genetic information for this economically important species.

Acidic Zeolite†L as a Highly Efficient Catalyst for Dehydration of Fructose to 5-Hydroxymethylfurfural in Ionic Liquid.

Zeolite L was synthesized by the hydrothermal method and post-treated by NH4 exchange to adjust its acidity. The samples were systematic characterized by various techniques including XRD, X-ray fluorescence spectroscopy, N2 adsorption-desorption, scanning electron microscopy, pyridine IR spectroscopy, and NH3 temperature-programmed desorption. The results demonstrated that the NH4 -exchange post-treatment increased the surface area, micropore volume, and acidity of zeolite L. The catalytic performance of the samples was tested in the dehydration of fructose to 5-hydroxymethylfurfural (HMF) in ionic liquid (1-butyl-3-methylimidazolium bromide, [bmim]Br). 99.1 % yield of HMF was obtained when the KL-80 °C-1 h sample (KL zeolite treated with 1 m NH4 NO3 solution at 80 °C for 1 h) was used. The high efficiency could be attributed to the appropriate acid properties of the catalyst. The zeolite catalyst could be reused four times without significant decrease in activity.