This Review discusses, along with the historical background, the principles as well as proof‐of‐concept studies of the crystalline sponge (CS) method, a new single‐crystal X‐ray diffraction (SCXRD) ...method for the analysis of the structures of small molecules without sample crystallization. The method uses single‐crystalline porous coordination networks (crystalline sponges) that can absorb small guest molecules within their pores. The absorbed guest molecules are ordered in the pores through molecular recognition and become observable by conventional SCXRD analysis. The complex {(ZnI2)3(tpt)2⋅x(solvent)}n (tpt=tris(4‐pyridyl)‐1,3,5‐triazine) was first proposed as a crystalline sponge and has been most generally used. Crystalline sponges developed later are also discussed here. The principle of the CS method can be described as “post‐crystallization” of the absorbed guest, whose ordering is templated by the pre‐latticed cavities. The method has been widely applied to synthetic chemistry as well as natural product studies, for which proof‐of‐concept examples will be shown here.
Crystal growth is not needed for single‐crystal X‐ray structure analysis when the crystalline sponge method is used. This method makes use of single‐crystalline porous coordination networks (“crystalline sponges”) that can absorb small guest molecules within the pores and make the absorbed guests observable by conventional single‐crystal diffraction. This Review focuses on the principles of this approach as well as proof‐of‐concept studies.
Traditionally, generation of new plants with improved or desirable features has relied on laborious and time-consuming breeding techniques. Genome-editing technologies have led to a new era of genome ...engineering, enabling an effective, precise, and rapid engineering of the plant genomes. Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (CRISPR/Cas9) has emerged as a new genome-editing tool, extensively applied in various organisms, including plants. The use of CRISPR/Cas9 allows generating transgene-free genome-edited plants ("null segregants") in a short period of time. In this review, we provide a critical overview of the recent advances in CRISPR/Cas9 derived technologies for inducing mutations at target sites in the genome and controlling the expression of target genes. We highlight the major breakthroughs in applying CRISPR/Cas9 to plant engineering, and challenges toward the production of null segregants. We also provide an update on the efforts of engineering Cas9 proteins, newly discovered Cas9 variants, and novel CRISPR/Cas systems for use in plants. The application of CRISPR/Cas9 and related technologies in plant engineering will not only facilitate molecular breeding of crop plants but also accelerate progress in basic research.
Abstract
Adoption of CRISPR–Cas systems, such as CRISPR–Cas9 and CRISPR–Cas12a, has revolutionized genome engineering in recent years; however, application of genome editing with CRISPR type I—the ...most abundant CRISPR system in bacteria—remains less developed. Type I systems, such as type I-E, and I-F, comprise the CRISPR-associated complex for antiviral defense (‘Cascade’: Cas5, Cas6, Cas7, Cas8 and the small subunit) and Cas3, which degrades the target DNA; in contrast, for the sub-type CRISPR–Cas type I-D, which lacks a typical Cas3 nuclease in its CRISPR locus, the mechanism of target DNA degradation remains unknown. Here, we found that Cas10d is a functional nuclease in the type I-D system, performing the role played by Cas3 in other CRISPR–Cas type I systems. The type I-D system can be used for targeted mutagenesis of genomic DNA in human cells, directing both bi-directional long-range deletions and short insertions/deletions. Our findings suggest the CRISPR–Cas type I-D system as a unique effector pathway in CRISPR that can be repurposed for genome engineering in eukaryotic cells.
Mycosporine-like amino acids (MAAs) are water-soluble molecules that absorb UV-A and UV-B radiation and disperse the energy as heat. MAAs show great diversity in their molecular structures, which ...exhibit a range of molecular weights spanning 188 to 1050 Daltons. MAAs are utilized in a wide variety of organisms including prokaryotes and eukaryotic micro-organisms that inhabit aquatic, terrestrial, and marine environments. These features suggest that MAAs are stable and fundamental molecules that allow these organisms to live under UV irradiation. MAAs are thought to have been greatly important to ancient forms of life on Earth, functioning as a primary sunscreen to reduce short-wavelength light. Structurally different MAAs might have been developed in MAA-producing organisms during their environmental adaptation. Harmful irradiation directly damages biomolecules, including lipids, proteins and DNA, and induces oxidative stress through radical-propagating processes. Thus, MAAs are expected to play an additional role in the antioxidant system. This review focuses on MAAs with radical scavenging activities. To cover all the reported MAAs known thus far, we surveyed the CAS database and have summarized the structures and the chemical and physical properties of these MAAs, including their antioxidant activities.
Abstract
Exercise intolerance is a primary manifestation in patients with heart failure with preserved ejection fraction (HFpEF) and is associated with abnormal hemodynamics and a poor quality of ...life. Two multiparametric scoring systems have been proposed to diagnose HFpEF. This study sought to determine the performance of the H
2
FPEF and HFA-PEFF scores for predicting exercise capacity and echocardiographic findings of intracardiac pressures during exercise in subjects with dyspnea on exertion referred for bicycle stress echocardiography. In a subset, simultaneous expired gas analysis was performed to measure the peak oxygen consumption (VO
2
). Patients with HFpEF (n = 83) and controls without HF (n = 104) were enrolled. The H
2
FPEF score was obtainable for all patients while the HFA-PEFF score could not be calculated for 23 patients (feasibility 88%). Both H
2
FPEF and HFA-PEFF scores correlated with a higher E/e′ ratio (r = 0.49 and r = 0.46), lower systolic tricuspid annular velocity (r = − 0.44 and = − 0.24), and lower cardiac output (r = − 0.28 and r = − 0.24) during peak exercise. Peak VO
2
and exercise duration decreased with an increase in H
2
FPEF scores (r = − 0.40 and r = − 0.32). The H
2
FPEF score predicted a reduced aerobic capacity (AUC 0.71,
p
= 0.0005), but the HFA-PEFF score did not (
p
= 0.07). These data provide insights into the role of the H
2
FPEF and HFA-PEFF scores for predicting exercise intolerance and abnormal hemodynamics in patients presenting with exertional dyspnea.
Background
Sarcopenia is closely associated with morbidity after pancreatic surgery. We investigated the impact of preoperative nutritional support and rehabilitation on patients undergoing ...pancreaticoduodenectomy.
Methods
This was a retrospective analysis of 101 patients who underwent pancreaticoduodenectomy. Skeletal muscle (SM) loss was defined using the SM index (cutoff level: 42 cm
2
/m
2
in men and 38 cm
2
/m
2
in women). A total of 33 and 30 patients received preoperative nutrition and prehabilitation, respectively. The neutrophil-to-lymphocyte ratio (NLR), Prognostic Nutritional Index (PNI), and modified Glasgow Prognostic Score (mGPS) values were calculated during the first visit and immediately before surgery.
Results
SM loss was present in 65 of 101 patients and was significantly correlated with female sex, older age, lower body mass index, and low PNI. Preoperative nutritional support and prehabilitation prevented the decrease in PNI values in patients with SM loss. The NLR significantly improved in patients with SM loss who received nutritional support and prehabilitation. In patients with SM loss, the lack of preoperative nutrition and prehabilitation was an independent risk factor for postoperative pancreatic fistula.
Conclusions
Preoperative nutritional support and prehabilitation may reduce the incidence of pancreatic fistula in patients with SM loss and improve the surgical outcomes of patients undergoing pancreaticoduodenectomy.
Diosgenin is a spiroketal steroidal natural product extracted from plants and used as the single most important precursor for the world steroid hormone industry. The sporadic occurrences of diosgenin ...in distantly related plants imply possible independent biosynthetic origins. The characteristic 5,6-spiroketal moiety in diosgenin is reminiscent of the spiroketal moiety present in anthelmintic avermectins isolated from actinomycete bacteria. How plants gained the ability to biosynthesize spiroketal natural products is unknown. Here, we report the diosgenin-biosynthetic pathways in himalayan paris (Paris polyphylla), a monocot medicinal plant with hemostatic and antibacterial properties, and fenugreek (Trigonella foenum-graecum), an eudicot culinary herb plant commonly used as a galactagogue. Both plants have independently recruited pairs of cytochromes P450 that catalyze oxidative 5,6-spiroketalization of cholesterol to produce diosgenin, with evolutionary progenitors traced to conserved phytohormone metabolism. This study paves the way for engineering the production of diosgenin and derived analogs in heterologous hosts.
Bacterial cellulose, as an important renewable bioresource, exhibits excellent mechanical properties along with intrinsic biodegradability. It is expected to replace non-degradable plastics and ...reduce severe environmental pollution. In this study, using dry jet-wet spinning and stretching methods, we fabricate cellulose composite macrofibers using nanofibrillated bacterial cellulose (BCNFs) which were obtained by agitated fermentation. Ionic liquid (IL) was used as a solvent to perform wet spinning. In this process, force-induced alignment of BCNFs was applied to enhance the mechanical properties of the macrofibers. The results of scanning electron microscopy revealed the well-aligned structure of BCNF along the fiber axis. The fiber prepared with an extrusion rate of 30 m min
and a stretching ratio of 46% exhibited a strength of 174 MPa and a Young's modulus of 13.7 GPa. In addition, we investigated the co-spinning of carboxymethyl cellulose-containing BCNF with chitosan using IL as a "container", which indicated the compatibility of BCNFs with other polysaccharides. Recycling of the ionic liquid was also verified to validate the sustainability of our strategy. This study provides a scalable method to fabricate bacterial cellulose composite fibers, which can be applied in the textile or biomaterial industries with further functionalization.
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•Tailoring the interactions in PAN/lignin blends for carbon nanofiber production.•Acetylation of lignin improves PAN/lignin polymer miscibility.•Acetylation hinders ...thermostabilization processes that involve hydroxyl groups.•Partial acetylation is essential for improving the mechanical properties.
Lignin/polyacrylonitrile (PAN) precursors can provide a green solution for lowering the cost while adequately maintaining the mechanical performance of carbon fibers, opening the gates for energy efficient lightweight materials to reach price-sensitive markets. We anticipated that improving the interactions between hydrophobic PAN chains and lignin, abundant in hydrophilic –OH groups, is important issue for obtaining a more aligned polymeric network, advantageous for the mechanical performance of carbon fibers. A controlled acetylation using acetic anhydride or isopropenyl acetate (IPA; in DMSO/EmimOAc) allowed us to step-by-step increase the degree of substitution of lignin and fine-tune the thermal characteristics as well as the miscibility of the blends, thus tailoring the mechanical properties of the resulting electrospun carbon fiber mats, along with the morphological evolution of the fibrous network. Differential scanning calorimetry and rheometry results indicated that by increasing the amount of substituents, the complex hydrogen bonding network connecting lignin molecules gradually breaks down leading to an increase in lignin/PAN polymer blend miscibility. However, it also became apparent that by masking hydroxyl groups important free radical mediated processes during the stabilization step might be inhibited, this phenomenon appeared to be more pronounced when aliphatic hydroxyl groups are selectively acetylated (IPA in DMSO/EmimOAc). Carbon fiber mats with the best mechanical performance were obtained only via controlled partial acetylation of kraft lignin with an almost 3-fold improvement in tensile strength (about 2-fold increase in elastic modulus) compared to the unmodified lignin-based fibrous materials. Our study holds promise for the realization of potentially low-cost quality carbon fibers.
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