Publications by authors named "Mengmeng Kong"

8 Publications

  • Page 1 of 1

Comparison of Fecal Collection Methods on Variation in Gut Metagenomics and Untargeted Metabolomics.

mSphere 2021 Sep 15:e0063621. Epub 2021 Sep 15.

State Key Laboratory of Genetic Engineering School of Life Sciences, Human Phenome Institute, Fudan Universitygrid.8547.e, Shanghai, China.

Integrative analysis of high-quality metagenomics and metabolomics data from fecal samples provides novel clues for the mechanism underpinning gut microbe-human interactions. However, data regarding the influence of fecal collection methods on both metagenomics and metabolomics are sparse. Six fecal collection methods (the gold standard [GS] [i.e., immediate freezing at -80°C with no solution], 95% ethanol, RNAlater, OMNIgene Gut, fecal occult blood test [FOBT] cards, and Microlution) were used to collect 88 fecal samples from eight healthy volunteers for whole-genome shotgun sequencing (WGSS) and untargeted metabolomic profiling. Metrics assessed included the abundances of predominant phyla and α- and β-diversity at the species, gene, and pathway levels. Intraclass correlation coefficients (ICCs) were calculated for microbes and metabolites to estimate (i) stability (day 4 versus day 0 within each method), (ii) concordance (day 0 for each method versus the GS), and (iii) reliability (day 4 for each method versus the GS). For the top 4 phyla and microbial diversity metrics at the species, gene, and pathway levels, generally high stability and reliability were observed for most methods except for 95% ethanol; similar concordances were seen for different methods. For metabolomics data, 95% ethanol showed the highest stability, concordance, and reliability (median ICCs = 0.71, 0.71, and 0.65, respectively). Taken together, OMNIgene Gut, FOBT cards, RNAlater, and Microlution, but not 95% ethanol, were reliable collection methods for gut metagenomic studies. However, 95% ethanol was the best for preserving fecal metabolite profiles. We recommend using separate collecting methods for gut metagenomic sequencing and fecal metabolomic profiling in large population studies. The choice of fecal collection method is essential for studying gut microbe-human interactions in large-scale population-based research. In this study, we examined the effects of fecal collection methods and storage time at ambient temperature on variations in the gut microbiome community composition; microbial diversity metrics at the species, gene, and pathway levels; antibiotic resistance genes; and metabolome profiling. Our findings suggest using different fecal sample collection methods for different data generation purposes. OMNIgene Gut, FOBT cards, RNAlater, and Microlution, but not 95% ethanol, were reliable collection methods for gut metagenomic studies. However, 95% ethanol was the best for preserving fecal metabolite profiles.
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http://dx.doi.org/10.1128/mSphere.00636-21DOI Listing
September 2021

PetM is Essential for the Stabilization and Function of the Cytochrome b6f Complex in Arabidopsis.

Plant Cell Physiol 2021 Jul 20. Epub 2021 Jul 20.

National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences/Institutes of Plant Physiology and Ecology, 300 Fenglin Road, Shanghai, 200032, PR China.

The cytochrome b6f (cyt b6f) acts as a center linker of electron transport between photosystem I and II in oxygenic photosynthesis. PetM, one of the eight subunits of the cyt b6f complex, is a small hydrophobic subunit at the outside periphery, the functional mechanism of which remains to be elucidated in higher plants. In this work, we found that unlike the PetM mutant in Synechocystis sp. PCC 6803, the Arabidopsis thaliana PetM mutant showed a bleached phenotype with yellowish leaves, block of photosynthetic electron transport and loss of photo-autotrophy, similar to the Arabidopsis PetC mutant. Although PetM is relatively conserved between higher plants and cyanobacteria, Synechocystis PetM could not rescue the PetM-knockout phenotype in Arabidopsis. We provide evidence that the Synechocystis PetM did not stably bind to the Arabidopsis cyt b6f complex. Based on these results, we suggest that PetM is required in Arabidopsis to maintain function of the cyt b6f complex, likely through its close link with core subunits to form a tight "fence" which stabilizes the core of the complex.
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http://dx.doi.org/10.1093/pcp/pcab116DOI Listing
July 2021

Melatonin and Its Homologs Induce Immune Responses Receptors trP47363-trP13076 in .

Front Plant Sci 2021 30;12:691835. Epub 2021 Jun 30.

Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Department of Plant Pathology, College of Plant Protection, Ministry of Education, Nanjing Agricultural University, Nanjing, China.

Melatonin (N-acetyl-5-methoxytryptamine), a naturally occurring small molecule, can protect plants against abiotic stress after exogenous treatmenting with it. It is not known if melatonin homologs, such as 5-methoxytryptamine and 5-methoxyindole, that are easy and more cost-effective to synthesize can stimulate the plant immune system in the same manner as melatonin. In the present study, we assessed the biological activity of the melatonin homologs, 5-methoxytryptamin and 5-methoxyindole. The results showed that melatonin and its homologs all induced disease resistance against in plants. The application of all three compounds also induced stomatal closure and the production of reactive oxygen species. Gene expression analysis indicated that the expression of genes involved in hydrogen peroxide (HO), nitric oxide (NO) production, and salicylic acid (SA) biosynthesis was significantly upregulated by all three compounds. Four homologs of the melatonin receptors were identified by blasting search with the phytomelatonin receptor in . Molecular docking studies were also used to identify four putative melatonin receptors in . Further experimentation revealed that silencing of the melatonin receptors trP47363 and trP13076 in compromised the induction of stomatal closure, gene expression and SA accumulation by all three compounds. Collectively, our data indicate that the induction of defense responses in by melatonin, 5-methoxytryptamine, and 5-methoxyindole involves the melatonin receptors trP47363 and trP13076.
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http://dx.doi.org/10.3389/fpls.2021.691835DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8278317PMC
June 2021

High-speed giant magnetostrictive actuator using laminated silicon steel core.

Rev Sci Instrum 2021 May;92(5):055004

Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, HeFei 230026, China.

The high-frequency eddy current loss limits the output speed of the giant magnetostrictive actuator (GMA). This paper investigates a GMA using a laminated silicon steel core. Compared with the integral silicon steel core, the laminated silicon steel core can reduce the equivalent conductivity and eddy currents. The laminated structure reduces the magnetic reluctance of the core and increases the magnetic field intensity in the giant magnetostrictive material rod. Therefore, the actuator can output large vibration amplitude under high-frequency magnetic field. At the sinusoidal excitation current of 35 A (rms) @ 2 kHz, the output vibration amplitude of the actuator using the laminated silicon steel core is 11.1 µm @ 4 kHz, which is 44.2% higher than that of the actuator with the integral silicon steel core. This indicates that the laminated structure of the magnetic core is beneficial to improve the output speed of GMA.
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http://dx.doi.org/10.1063/5.0044522DOI Listing
May 2021

Discovery and preliminary mechanism of 1-carbamoyl β-carbolines as new antifungal candidates.

Eur J Med Chem 2021 Oct 2;222:113563. Epub 2021 Jun 2.

Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, 210095, China. Electronic address:

Natural β-carboline alkaloids are ideal models for the discovery of pharmaceutically important entities. Various 1-substituted β-carbolines were synthesized from commercially inexpensive tryptophan and demonstrated significant in vitro antifungal activity against G. graminis. Significantly, compound 4m (EC = 0.45 μM) with carboxamide at 1-position displayed the best efficacy and nearly 20 folds enhancement in antifungal potential compared to Silthiopham (EC = 8.95 μM). Moreover, compounds 6, 7, and 4i exhibited excellent in vitro antifungal activities and in vivo protective and curative activities against B. cinerea and F. graminearum. Preliminary mechanism studies revealed that compound 4m caused reactive oxygen species accumulation, cell membrane destruction, and deregulation of histone acetylation. These findings indicated that 1-carbamoyl β-carboline can be selected as a promising model for the discovery of novel and broad-spectrum fungicide candidates.
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http://dx.doi.org/10.1016/j.ejmech.2021.113563DOI Listing
October 2021

More stories to tell: NONEXPRESSOR OF PATHOGENESIS-RELATED GENES1, a salicylic acid receptor.

Plant Cell Environ 2021 06 3;44(6):1716-1727. Epub 2021 Feb 3.

Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base of Ministry of Science and Technology, Nanjing, China.

Salicylic acid (SA) plays pivotal role in plant defense against biotrophic and hemibiotrophic pathogens. Tremendous progress has been made in the field of SA biosynthesis and SA signaling pathways over the past three decades. Among the key immune players in SA signaling pathway, NONEXPRESSOR OF PATHOGENESIS-RELATED GENES1 (NPR1) functions as a master regulator of SA-mediated plant defense. The function of NPR1 as an SA receptor has been controversial; however, after years of arguments among several laboratories, NPR1 has finally been proven as one of the SA receptors. The function of NPR1 is strictly regulated via post-translational modifications and transcriptional regulation that were recently found. More recent advances in NPR1 biology, including novel functions of NPR1 and the structure of SA receptor proteins, have brought this field forward immensely. Therefore, based on these recent discoveries, this review acts to provide a full picture of how NPR1 functions in plant immunity and how NPR1 gene and NPR1 protein are regulated at multiple levels. Finally, we also discuss potential challenges in future studies of SA signaling pathway.
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http://dx.doi.org/10.1111/pce.14003DOI Listing
June 2021

[Preparation and identification of polyclonal antibodies against Moraxella catarrhalis UspA1].

Sheng Wu Gong Cheng Xue Bao 2018 Jan;34(1):102-109

Key Laboratory of Fermentation Engineering, Ministry of Education, School of Food and Biological of Engineering, Hubei University of Technology, Wuhan 430068, Hubei, China.

To prepare polyclonal antibodies (PcAb) against UspA1 of Moraxella catarrhalis (Mc), we used bioinformatic analysis to determine the surface exposed region in this protein that holds the antigen epitopes. Then the corresponding coding sequences for this fragment was artificially synthesized according to the codon usage of Escherichia coli. The gene fragment was then subcloned into the prokaryotic expression vector pET-28a(+) and expressed in E. coli rosseta (DE3), and then the recombinant UspA1-His proteins were purified. Two New Zealand white rabbits were immunized with this protein to prepare antiserum. The resulting PcAb was then purified from the antiserum with Protein A affinity column. The results of fluorescence antibody assay, enzyme linked immunosorbent assay and Western blotting analysis showed that the PcAb could specifically recognize the surface exposed region of UspA1 on Mc. The preparation of the PcAb laid a foundation of further development of rapid detection technique for M. catarrhalis.
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http://dx.doi.org/10.13345/j.cjb.170095DOI Listing
January 2018

Gene expression in benzene-exposed workers by microarray analysis of peripheral mononuclear blood cells: induction and silencing of CYP4F3A and regulation of DNA-dependent protein kinase catalytic subunit in DNA double strand break repair.

Chem Biol Interact 2010 Mar 29;184(1-2):207-11. Epub 2009 Dec 29.

School of Public Health, Wuhan University, 185 Donghu Rd, Wuhan, Hubei 430071, China.

Benzene causes hematotoxicity and leukemia in humans. To analyze benzene-caused aberrant gene expression, we examined differential gene expression by microarray analysis of peripheral mononuclear blood cells from seven workers diagnosed with benzene poisoning and seven matched controls. Twenty-two genes were found up-regulated and 18 down-regulated in benzene patients compared with controls. Here we report the characterization of two benzene-regulated genes. CYP4F3A, which encodes the leukotriene B(4) (LTB(4)) omega-hydroxylase, is important for inactivation of LTB(4) in neutrophils. CYP4F3A mRNA was found elevated in all patients; moreover, CYP4F3A mRNA and protein were induced by benzene metabolite phenol in HL-60 and K562 cells as well as ex vivo in human peripheral neutrophils. Silencing of CYP4F3A in HL-60 cells by lentiviral delivery of CYP4F3A-specific siRNA reduced cell survival to 56%, 44%, 22%, 14%, and 3% at 3, 4, 5, 6, and 7 days, respectively; the results suggest that CYP4F3A is a critical positive regulator of HL-60 proliferation. DNA-dependent protein kinase catalytic subunit (DNA-PKcs) regulates non-homologous end joining (NHEJ) in DNA double strand break (DSB) repair. DNA-PKcs mRNA was found consistently increased in the patients and DNA-PKcs mRNA and protein were induced by hydroquinone in HL-60 cells. In a DSB model, hydroquinone induced the formation of gamma-H2AX foci, a marker of DSBs, in HL-60 cells. The findings indicate that hydroquinone induces DSBs and induction correlates with elevated levels of DNA-PKcs and NHEJ. Similar results were obtained in K562 cells treated with phenol. Since NHEJ is error-prone, induction of DNA-PKcs and NHEJ may contribute to mutagenesis and leukemia by benzene. To our knowledge, the study demonstrated for the first time that benzene and metabolites induce CYP4F3A and DNA-PKcs both in vivo and in vitro. Induction of the genes may play a role in the pathogenesis of benzene hematotoxicity and serve as biomarkers of benzene exposure.
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http://dx.doi.org/10.1016/j.cbi.2009.12.024DOI Listing
March 2010
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