Extraction and Antioxidant Activity Analysis of Crude Polysaccharides from Wild Lactarius volemus Fr. in Yunnan Province

[ Objective ] This study aimed to investigate the optimal extraction process of crude polysaccharides from wild Lactarius volemus Fr. in Yunnan Province and preliminarily analyzed its antioxidant activity in vitro. [ Method ] With water extraction and alcohol precipitation method, the optimal conditions for extracting crude polysaccharides from wild L. volemus Ft. were screened by single-factor and orthogonal experiments. The antioxidant activity of the extracted crude polysac- charides was determined with DPPH assay. [ Result ] The optimal conditions for pigment removal with activated carbon were： activated carbon amount of 20 g/L, water bath time of 40 min, water bath temperature of40 ℃ ; the optimal conditions for extracting crude polysaccharides from wild L. vo/emus Fr. with hot water ex- traction method were： hot water extraction time of 3 h, solid-liquid ratio of 1： 45, extraction frequency of twice. Under the optimized extraction conditions, the yield of crude polysaccharides was 21.33 mg/g. In addition, the antioxidant activity of 0. 665 mg/ml crude polysaccharides was 52.46% ; the amount of crude polysac- eharides was proportional to the antioxidant activity. [ Conclusion] Hot water extraction method can be used as a high-efficiency extraction technology of crude pol- ysaecharides from wild L. volemus Fr. with simple operation and low costs. Crude polysaccharides extracted from L. volemus Ft. exhibited certain antioxidant activi- ty in vitro.

PKC-SWI6 signaling regulates asexual development,cell wall integrity,stress response,and lifestyle transition in the nematode-trapping fungus Arthrobotrys oligospora

Predatory fungi possess intricate signal transduction systems that regulate their development and support successful infection of the host.Herein,we characterized three components of the cell wall integrity-controlling pathway,namely protein kinase C(Ao PKC),SLT2-MAPK(Ao SLT2),and SWI6(Ao SWI6),in a representative nematode-trapping fungus Arthrobotrys oligospora,using gene disruption and multi-omics approaches.The phenotypic traits(such as mycelia development,conidiation,stress response,and trap morphogenesis) and metabolic profiles of ΔAopkc and ΔAoswi6 mutants were similar but differed from those of the ΔAoslt2 mutants.Transcriptomic analysis indicated that the genes differentially expressed in the absence of Aoswi6 were involved in DNA replication,repair,and recombination during trap formation.Moreover,the yeast two-hybrid assay showed that Ao PKC interacted with Ao SWI6,suggesting that in A.oligospora,PKC can directly regulate SWI6,bypassing the SLT2signaling cascade.Conclusively,our findings deepen our understanding of the regulatory mechanism of asexual development and lifestyle switching in nematode-trapping fungi.

AoATG5 plays pleiotropic roles in vegetative growth,cell nucleus development,conidiation,and virulence in the nematode-trapping fungus Arthrobotrys oligospora

Autophagy is an evolutionarily conserved process in eukaryotes,which is regulated by autophagy-related genes(ATGs).Arthrobotrys oligospora is a representative species of nematode-trapping(NT)fungi that can produce special traps for nematode predation.To elucidate the biological roles of autophagy in NT fungi,we characterized an orthologous Atg protein,AoAtg5,in A.oligospora.We found that AoATG5 deletion causes a significant reduction in vegetative growth and conidiation,and that the transcript levels of several sporulation-related genes were significantly downregulated during sporulation stage.In addition,the cell nuclei were significantly reduced in theΔAoATG5 mutant,and the transcripts of several genes involved in DNA bio-synthesis,repair,and ligation were significantly upregulated.InΔAoATG5 mutants,the autophagic process was significantly impaired,and trap formation and nematocidal activity were significantly decreased.Comparative transcriptome analysis results showed that AoAtg5 is involved in the regulation of multiple cellular processes,such as autophagy,nitrogen metabolism,DNA biosynthesis and repair,and vesicular transport.In summary,our results suggest that AoAtg5 is essential for autophagy and significantly contributes to vegetative growth,cell nucleus development,sporulation,trap formation,and pathogenicity in A.oligospora,thus providing a basis for future studies focusing on related mechanisms of autophagy in NT fungi.

Metal Free Mono- and 2,3-Bis-sulfenylation of Indoles in Water with Sodium Sulfinates as a Sulfur Source

An iodine-PPh3 mediated sulfenylation of indoles in water with stable and odorless sodium sulfinates as the sulfur source is described. The reaction could afford monosulfenylated indoles in moderate to excellent yields under metal free conditions. Moreover, double C--H sulfenylation of in- doles at 2- and 3-positions has also been achieved by using excess sodium sulfinates under the optimized reaction conditions.

Square Planar Nickel（II） Complexes with Halogenated o-Diiminobenzosemiquinonato Ligation： Synthesis, Characterization, and Redox Property

Seven square planar bis（o-diiminobenzosemiquinonato）nickel（II） complexes, [Ni（o-C6H4（NH）（NAr））2] （Ar= Mes, 1; p-F-C6H4, 2; p-CI-C6H4, 3）, [Ni（o-4,5-F2-C6H2（NH）（NPh））2] （4）, and [Ni（o-4,5-CIz-C6H2（NH）（NAr））2] （Ar =Ph, 5; 2,6-F2-C6H3, 6; 2,6-C12-C6H3, 7）, have been synthesized and characterized by 1H NMR, 13C NMR, 19F NMR, IR, UV-Vis-NIR, elemental analyses, HRMS, as well as single-crystal X-ray diffraction studies （1 and 7）. The cyclic voltammograms of these complexes exhibit two reversible redox processes of [NiLe]0n- and [NIL2]l /2 , and one irreversible process of [NiL2]~n＋. Substituent effects on the redox properties of these complexes, in addi- tion with those of the known complexes [Ni（o-C6Ha（NH）（NPh））2] （8） and [Ni（o-3,5-Butz-C6Hz（NH）2）2] （9）, are identified by comparing the half-wave potentials of the reduction waves, as 1 ~ 9 〈 8 ~ 2 〈 3 〈 4 〈 5 〈 7 〈 6, reflect- ing the ease of reduction of [NIL2] parallels the electron-donating and -withdrawing ability of the substituent group. Reduction of 1 with one or two equivalents of sodium metal in THF has led to the isolation of [Na（THF）3][I] and [Na（THF）3]2[1]. The structure data of these two complexes revealed by low-temperature X-ray crystallography suggest their corresponding electronic structures of [Nill（lL-1 ）（IL2-）]1- and [Ni1]（1L2 ）212-, which are in line with those of [9]n （n = 1-, 2-） suggested by spectroelectrochemical study.

Regioselective Synthesis of Aurone Derivatives via PBu_(3)-Catalyzed Cyclization of 2-Alkynoylphenols

Aurone derivatives were synthesized in good to high yields by PBu_(3)-catalyzed intramolecular 5-exo cyclization of 2-alkynoylphenols.The reaction proceeds in high regioselectivity without forming 6-endo cyclization products.

K_(2)S_(2)O_(8)-mediated acylarylation of unactivated alkenes via acyl radical addition/C–H annulation cascade of N-allyl-indoles with silver cocatalysis

A silver-catalyzed,K_(2)S_(2)O_(8)-mediated protocol to access regioselective acylarylation of unactivated alkenes was developed.The reaction between N-allyl-indoles andα-oxocarboxylic acids proceeded smoothly and involved an acyl radical addition/C–H cyclization cascade.The protocol showed a broad substrate scope and good tolerance of functional groups.The reaction proceeded with both internal and terminal alkenes to furnish many functional pyrrolo[1,2-a]indoles bearing the ketone carbonyl group,and this feature also provides the potential to construct structurally complex N-containing heterocycles.