[Effects of exogenous 6-BA on flag leaf physiology, yield, and quality of wheat after low temperature stress at booting stage]. / 外源6-BA对孕穗期低温胁迫后小麦旗叶生理、产量及品质的影响.

Low temperature (LT) in spring usually occurs at the booting of winter wheat, resulting in reduction of wheat yield. In this study, we used the LT-sensitive wheat cultivar 'Wanmai 52' and the LT-insensitive wheat cultivar 'Yannong 19' as experimental materials to conduct LT treatment (-2 ℃ and 0 ℃) at booting stage. After the LT treatment, we sprayed 6-benzylaminoadenine (6-BA) solutions with concentrations of 10, 20, and 30 mg·L-1 respectively, with equal mass distilled water as control to investigate the effects of spraying 6-BA on the physiological characteristics, yield and quality of wheat flag leaves after LT stress at booting stage. The results showed that compared with the control, young ear of wheat treated with exogenous spraying 6-BA was fuller, the floret morphology was improved, and the number of vascular bundles under the spike was increased. 6-BA application promoted the accumulation of soluble sugar, soluble protein, and proline in flag leaves. The activities of peroxidase and superoxide dismutase were increased, and the content of malondialdehyde was decreased. Exogenous 6-BA application decreased the number of degenerated spikes of wheat, increased the number of grains per spike and 1000-grain weight, as well as the contents of grain protein, wet gluten, and sedimentation value. In summary, exogenous 6-BA application could effectively alleviate the effects of LT stress on flag leaf and yield of wheat. Under the conditions of this experiment, the mitigation effect of spraying 6-BA solution on Yannong 19 was higher than that of Wanmai 52, and the mitigation effect of spraying 20 mg·L-1 6-BA solution on low temperature stress was the best.

Single-neuron projectome-guided analysis reveals the neural circuit mechanism underlying endogenous opioid antinociception.

Endogenous opioid antinociception is a self-regulatory mechanism that reduces chronic pain, but its underlying circuit mechanism remains largely unknown. Here, we showed that endogenous opioid antinociception required the activation of mu-opioid receptors (MORs) in GABAergic neurons of the central amygdala nucleus (CEA) in a persistent-hyperalgesia mouse model. Pharmacogenetic suppression of these CEAMOR neurons, which mimics the effect of MOR activation, alleviated the persistent hyperalgesia. Furthermore, single-neuron projection analysis revealed multiple projectome-based subtypes of CEAMOR neurons, each innervating distinct target brain regions. We found that the suppression of axon branches projecting to the parabrachial nucleus (PB) of one subtype of CEAMOR neurons alleviated persistent hyperalgesia, indicating a subtype- and axonal-branch-specific mechanism of action. Further electrophysiological analysis revealed that suppression of a distinct CEA-PB disinhibitory circuit controlled endogenous opioid antinociception. Thus, this study identified the central neural circuit that underlies endogenous opioid antinociception, providing new insight into the endogenous pain modulatory mechanisms.

Brønsted Acid-Catalyzed Intramolecular Tandem Double Cyclization of γ-Hydroxy Acetylenic Ketones with Alkynes into Naphtho[1,2-b]furan-3-ones.

A metal-free and atom-economic route for the synthesis of naphtho[1,2-b]furan-3-ones has been realized via p-TsOH·H2O-catalyzed intramolecular tandem double cyclization of γ-hydroxy acetylenic ketones with alkynes in formic acid. The benzene-linked furanonyl-ynes are the key intermediates obtained by the scission/recombination of C-O double bonds. Further, the structural modifications of the representative product were implemented by reduction, demethylation, substitution, and [5 + 2]-cycloaddition.

A non-canonical binding interface in the crystal structure of HIV-1 gp120 core in complex with CD4.

Numerous crystal structures of HIV gp120 have been reported, alone or with receptor CD4 and cognate antibodies; however, no sole gp120/CD4 complex without stabilization by an antibody is available. Here, we report a crystal structure of the gp120/CD4 complex without the aid of an antibody from HIV-1 CRF07_BC, a strain circulating in China. Interestingly, in addition to the canonical binding surface, a second interacting interface was identified. A mutagenesis study on critical residues revealed that the stability of this interface is important for the efficiency of Env-mediated membrane fusion. Furthermore, we found that a broad neutralizing antibody, ibalizumab, which targets CD4 in the absence of gp120, occupies the same binding surface as the second interface identified here on gp120. Therefore, we identified the possibility of the involvement of a second gp120-CD4 interaction interface during viral entry, and also provided a reasonable explanation for the broad activity of neutralizing antibody ibalizumab.

[Construction of expression vector pLCK-CD69-IRES-EGFP and generation of CD69 transgenic mice].

OBJECTIVE: To construct the expression vector pLCK-CD69-IRES-EGFP that contains mouse cell surface activation protein CD69 and enhanced green fluorescent protein(EGFP),and to generate CD69 transgenic mice based on this vector. METHODS: First, RNA was extracted from mouse lung tissue and cDNA was synthesized via reverse transcription. PCR primer was designed through the PubMed searching, then mouse CD69 DNA fragment was amplified with PCR. Second, this DNA fragment was subcloned to the pInsulater-LCK-IRES-EGFP plasmid and constructed the transgenic vector after the verification of nucleotide sequence. Third, the expression vector was then transfected into 293 T cells and its expression in 293 T cells was observed under fluorescence microscope. Last, microinjection was performed to transfer the expression vector pLCK-CD69-IRES-EGFP into fertilized eggs, which were implanted into pseudo-pregnant recipient mice. After birth the tail samples of the pups were obtained for the purpose of genotyping to determine the transgenic founders. Fluorescence microscope and flow cytometer were used to measure the expression of CD69 on cells. RESULTS: The construction of the expression vector pLCK-CD69-IRES-EGFP was verified by enzyme digestion and DNA sequencing. The transfected 293 T cell showed expression of the protein under fluorescence microscope. Identification of PCR for the tail tissue of the pups confirmed the present of CD69 transgene and resting lymphocytes demonstrated the expression of CD69. CONCLUSION: The construction of expression vector pLCK-CD69-IRES-EGFP and generation of CD69 transgenic mice have been successfully processed, which lays a foundation of the solid pattern studies in inflammatory diseases.