Unveiling the Noncovalent Interactions between Formamide and Heteroaromatics: Microwave Spectroscopy of the Formamide Complexes with Furan and Thiophene.

The noncovalent interactions between formamide (FM) and the heteroaromatic compounds (furan and thiophene) were investigated through microwave spectroscopy and theoretical calculations. Each of the investigated complexes exhibits a single rotational spectrum corresponding to the lowest energy structure predicted theoretically. In the detected structures, N-H···O and C-H···O hydrogen bonds dominate the complexation between FM and furan, resulting in a planar configuration. Conversely, a superposed configuration linked by a N-H···π hydrogen bond and C═O···π contact is observed for the FM-thiophene complex. In both cases, hydrogen bonding interactions with N-H as proton donor rank as the dominant forces, and the interaction energy of N-H···O is larger than that of N-H···π. It was found that the electrostatic component is the largest contributor to the attraction between FM and furan, while the dispersion component is the most significant attractive factor in the FM-thiophene complex. These findings highlight the distinct features of hydrogen bonding interactions of amides with heteroaromatics in the studied complexes.

Unveiling the underappreciated: The bonding features of C-H⋯S-S interactions observed from rotational spectroscopy.

The C-H⋯S-S interactions are fundamentally important to understand the stability of biomacromolecules and their binding with small molecules, but they are still underappreciated. Herein, we characterized the C-H⋯S-S interactions in model molecular complexes. The rotational spectra of the complexes of diethyl disulfide with CH2CH2 and CH2CHF were measured and analyzed. All the detected structures are mainly stabilized by a C-H⋯S-S hydrogen bond, providing stabilization energies of 2.3-7.2 kJ mol-1. Incidental C-H⋯π or C-H⋯F interactions enhance the stabilization of the complexes. London dispersion, which accounts for 54%-68% of the total attractions, is the main driving force of stabilization. The provided bonding features of C-H⋯S-S are crucial for understanding the stabilizing role of this type of interaction in diverse processes such as supramolecular recognition, protein stability, and enzyme activity.

Intermolecular amide and aldehyde interactions: rotational spectroscopy of the complexes of formaldehyde with 2-azetidinone and formamide.

The binary intermolecular complexes of amides and formaldehyde can be taken as suitable models to investigate the non-covalent interactions of a peptide with the carbonyl group. We herein studied the rotational spectra of the model complexes of 2-azetidinone-H2CO and formamide-H2CO generated in a helium supersonic jet. For each complex, one rotational spectra featuring hyperfine structures caused by the 14N quadrupole coupling effect was observed and assigned to its global minimum conformation. The detected isomers of both studied complexes are stabilized by a dominant amide hydrogen bond N-H⋯OC and a weaker C-H⋯O interaction, preferring the Cs symmetry. NBO and SAPT analyses provide quantitative estimation of the non-covalent interactions stabilizing the complexes.

Noncovalent Interactions between Aromatic Heterocycles and Carboxylic Acids: Rotational Spectroscopy of the Furan-Formic Acid and Thiophene-Formic Acid Complexes.

The binary molecular complexes formed between the aromatic heterocycles furan and thiophene with formic acid were investigated using pulsed-jet Fourier transform microwave spectroscopy and quantum chemical computations. For both of the complexes, rotational spectra of the lowest energy isomer were detected and assigned. Rotational spectroscopic results and density functional theory calculations support that the preferred conformation of the furan-formic acid complex is characterized by a relatively strong O-H···O and a weak C-H···O hydrogen bonds while the O-H···π and C-H···O hydrogen bonds stabilize the thiophene-formic acid complex. Natural bond orbital analysis further proves the experimental observation, suggesting that the strength of the O-H···O(furan) interaction is about two times stronger than that of O-H···π(thiophene). The symmetry adapted perturbation theory analysis reveals that electrostatic interaction is dominant in stabilizing the two complexes and that dispersion becomes significant in the thiophene-formic acid complex compared to furan-formic acid.

The transcription factor OsbHLH138 regulates thermosensitive genic male sterility in rice via activation of TMS5.

Thermosensitive genic male sterile (TGMS) lines favored heterosis exploitation in two-line hybrid rice. TMS5, a member of RNase Z cleavages the UbL40 mRNAs, plays an important role in two-line hybrid rice. Here, we identified a new TGMS mutant 93-11s, which lost two amino acids in the first exon of TMS5 gene and caused thermosensitive genic male sterility in rice. The tms5-2 cannot process mRNAs of the ubiquitin fusion ribosomal protein L40 (UbL40) and hence cause the mRNAs accumulation in restrictive temperature. Further, we identified a nucleus-localized bHLH transcription factor OsbHLH138, which can form the basic helix-loop-helix structure and bind the core region of tms5-2 promoter sequences by bHLH domain, and activate expression of tms5-2 by the acidic amino acid-rich domain. These results indicate a novel mechanism for the tms5-2 regulating thermosensitive male sterility of rice. By altering expression of OsbHLH138, we can regulate the expression level of TMS5 and the accumulation of UbL40 mRNAs to command the male fertility in different temperatures. The identification of OsbHLH138 provides breeders a new choice for development of TGMS rice lines, which will favor the sustainable development of two-line hybrid rice.

Hierarchical porous biochar from kelp: Insight into self-template effect and highly efficient removal of methylene blue from water.

Biochar is known to efficiently remove dyes especially for biochar with hierarchical pores and partial N-species. Here, a facile pyrolysis is used to yield N-doped biochar from kelp without additives, showing surface areas of 771 m2/g as temperature up to 1000 °C and hierarchical small-sized mesopores (2-4 nm) and wide meso-macropores (8-60 nm). A possible self-template mechanism from inorganics is proposed to form hierarchical pore architecture in biochar and used for methylene blue (MB) removal. Biochar pyrolyzed at 1000 °C is found to be efficient for MB removal with uptake of 379.8 mg/g under ambient conditions, one of the largest ever recorded uptakes for other biochar without activation, owing to synergistic effects of high surface areas, mesopores, and graphitized N-species. These results confirm that a facile pyrolysis for transformation of kelp into efficient dyes adsorbent is a cost-effective process for economic and environmental protection.

CoSe2 hollow microspheres with superior oxidase-like activity for ultrasensitive colorimetric biosensing.

As one of the transition metal dichalcogenide, CoSe2 has received much attention because of its superior physicochemical properties. In this work, a self-templated approach was proposed for constructing CoSe2 hollow microspheres by utilizing ZIF-67 hollow sphere as a template. In the followed selenylation process, selenium vapor reacts with cobalt ion in ZIF-67 to form CoSe2 microspheres. The obtained CoSe2 microspheres retain the cavity of the ZIF-67 and massive uniformly dispersed CoSe2 nanoparticles are embedded throughout carbon walls. The hollow interior and porous structure of CoSe2 microspheres provide an enhanced surface-volume ratio and short charge/mass transfer distance. The CoSe2 microspheres show a typical oxidase-like property able to promote 3,3',5,5'-tetramethylbenzidine (TMB) oxidation by dissolved oxygen to produce an intensive color reaction. Reactive oxygen species trials demonstrate that ·OH, 1O2 and O2•- radicals coexist in the TMB-CoSe2 system. Based on its inhibitive role, a rapid and ultrasensitive determination of glutathione was reached, showing four orders of magnitude linear range from 0.005 to 10 µM and a limit of detection of 4.62 nM (S/N = 3). The assay has been successfully used to glutathione determination in practical samples.

QTL Mapping of Seed Vigor of Backcross Inbred Lines Derived From Oryza longistaminata Under Artificial Aging.

Seed vigor is an important character of seed quality that promotes rice to germinate rapidly from soil and developing to a strong seedling, especially in the current rice direct-sowing production system. However, previous studies for seed vigor mainly concentrate in cultivars, and less reports involving in wild rice. In this study, 152 backcross inbred lines (BILs) derived from wild rice Oryza longistaminata were genotyped with re-sequencing technology, and QTLs for seed vigor related traits under normal and artificial aging treatment were analyzed. Totally, 36 QTLs were detected, of which, eight for germination potential (GP), 10 for germination rate (GR), 9 for seedling length (SL), and 9 for root length (RL). Among these, 14 novel QTLs were identified from O. longistaminata. Of which, six QTLs were related to germination, and eight related to seedling growth under aging stress. What's more, the major QTLs q9SL1.1, q6SL1.1, and q3SL1.1 for seedling length were fallen in the same locus and fine-mapped an interval about 90 Kb. The major QTLs q9GR8.1 and q9GP8.1 related with germination were fine-mapped to an interval about 90 Kb. This work will provide us basis for breeding of high seed vigor rice in rice breeding programs and further cloning of these genes.

Artificial Selection of Gn1a Plays an Important role in Improving Rice Yields Across Different Ecological Regions.

BACKGROUND: Rice is one of the most important crops, and it is essential to improve rice productivity to satisfy the future global food supply demands. Gn1a (OsCKX2), which encodes cytokinin oxidase/dehydrogenase, plays an important role in regulating rice grain yield. RESULTS: In this study, we analyzed the genetic variation of Gn1a, which influences grain yield through controlling the number of spikelets in rice. The allelic variations in the promoter, 5' untranslated region (UTR) and coding sequence (CDS) of Gn1a were investigated in 175 cultivars and 21 wild rice accessions. We found that Gn1a showed less sequence variation in the cultivars, but exhibited significant nucleotide diversity in wild rice. A total of 14 alleles, named AP1 to AP14, were identified in the cultivars based on the amino acid divergence of GN1A. Association analysis revealed that the number of spikelets and grain yield were significantly different between the different alleles. Phylogenetic analysis indicated that the three main alleles, AP3, AP8 and AP9, in the cultivars might originate from a common ancestor allele, AP1, in wild rice. CONCLUSIONS: Of these alleles in the cultivars, AP9 was suggested as the best allele in indica, as it has shown strong artificial selection in breeding high-yield rice in the past. It might be valuable to explore the high-yield-related alleles of Gn1a to develop high-yield rice cultivars in future breeding programs.