Safety assessment of a novel marine multi-stress-tolerant yeast Meyerozyma guilliermondii GXDK6 according to phenotype and whole genome-sequencing analysis

The application of microorganisms as probiotics is limited due to lack of safety evaluation.Here,a novel multi-stress-tolerant yeast Meyerozyma guilliermondii GXDK6 with aroma-producing properties was identified from marine mangrove microorganisms.Its safety and probiotic properties were assessed in accordance with phenotype and whole-genome sequencing analysis.Results showed that the genes and phenotypic expression of related virulence,antibiotic resistance and retroelement were rarely found.Hyphal morphogenesis genes(SIT4,HOG1,SPA2,ERK1,ICL1,CST20,HSP104,TPS1,and RHO1)and phospholipase secretion gene(VPS4)were annotated.True hyphae and phospholipase were absent.Only one retroelement(Tad1-65_BG)was found.Major biogenic amines(BAs)encoding genes were absent,except for spermidine synthase(JA9_002594),spermine synthase(JA9_004690),and tyrosine decarboxylase(inx).The production of single BAs and total BAs was far below the food-defined thresholds.GXDK6 had no resistance to common antifungal drugs.Virulence enzymes,such as gelatinase,DNase,hemolytic,lecithinase,and thrombin were absent.Acute toxicity test with mice demonstrated that GXDK6 is safe.GXDK6 has a good reproduction ability in the simulation gastrointestinal tract.GXDK6 also has a strong antioxidant ability,β-glucosidase,and inulinase activity.To sum up,GXDK6 is considered as a safe probiotic for human consumption and food fermentation.

Action of circulating and infiltrating B cells in the immune microenvironment of colorectal cancer by single-cell sequencing analysis

BACKGROUND The complexity of the immune microenvironment has an impact on the treatment of colorectal cancer(CRC),one of the most prevalent malignancies worldwide.In this study,multi-omics and single-cell sequencing techniques were used to investigate the mechanism of action of circulating and infiltrating B cells in CRC.By revealing the heterogeneity and functional differences of B cells in cancer immunity,we aim to deepen our understanding of immune regulation and provide a scientific basis for the development of more effective cancer treatment strategies.AIM To explore the role of circulating and infiltrating B cell subsets in the immune microenvironment of CRC,explore the potential driving mechanism of B cell development,analyze the interaction between B cells and other immune cells in the immune microenvironment and the functions of communication molecules,and search for possible regulatory pathways to promote the anti-tumor effects of B cells.METHODS A total of 69 paracancer(normal),tumor and peripheral blood samples were collected from 23 patients with CRC from The Cancer Genome Atlas database(https://portal.gdc.cancer.gov/).After the immune cells were sorted by multicolor flow cytometry,the single cell transcriptome and B cell receptor group library were sequenced using the 10X Genomics platform,and the data were analyzed using bioinformatics tools such as Seurat.The differences in the number and function of B cell infiltration between tumor and normal tissue,the interaction between B cell subsets and T cells and myeloid cell subsets,and the transcription factor regulatory network of B cell subsets were explored and analyzed.RESULTS Compared with normal tissue,the infiltrating number of CD20+B cell subsets in tumor tissue increased significantly.Among them,germinal center B cells(GCB)played the most prominent role,with positive clone expansion and heavy chain mutation level increasing,and the trend of differentiation into memory B cells increased.However,the number of plasma cells in the tumor microenvironment decreased significantly,and the plasma cells secreting IgA antibodies decreased most obviously.In addition,compared with the immune microenvironment of normal tissues,GCB cells in tumor tissues became more closely connected with other immune cells such as T cells,and communication molecules that positively regulate immune function were significantly enriched.CONCLUSION The role of GCB in CRC tumor microenvironment is greatly enhanced,and its affinity to tumor antigen is enhanced by its significantly increased heavy chain mutation level.Meanwhile,GCB has enhanced its association with immune cells in the microenvironment,which plays a positive anti-tumor effect.

Isolation and Analysis of α-Gliadin Gene Coding Sequences from Triticum durum

Three coding sequences of gliadins genes, designed as Gli2_Dul, Gli2_Du2 and Gli2_Du3, were isolated from the genomic DNA of Triticum durum accessions CItr5083. Gli2_Dul and Gli2_Du2 contain 945 and 864 bp, encoding the mature proteins with 314 and 287 amino acid residues, respectively. Gli2_Du3 is recognized as a pseudogene due to the stop codon occurring in the coding region. The pseudogenes, commonly occurring in gliadins family, are attributed to the single base change C→T. The amino acid sequences deduced from these gene sequences were characterized with the typical structure of α-gliadin proteins, including the toxic sequences （PSQQQP）. The peptide fraction PF（Y）PP（Q）is thought to be an extra unit of repetitive domain, slightly diverging from the previous report. Six cysteine residues were observed within two unique domains. Phylogenetic analysis showed Gli2_Du2 and Gli2_Du3 were closely related to the genes on chromosome 6A, whereas Gli2_Dul seems to be more homologous with the genes on chromosome 6B.

Cloning and Expression Analysis of Downy Mildew Resistance-Related cDNA Sequences in Melon

Melon downy mildew caused by Pseudoperonospora cubensis leads to significant losses in melon yields worldwide. Reverse-transcription Polymerase Chain Reaction （RT-PCR） was performed using cDNAs as templates from melon-Huangdanzi induced with fungus Pseudoperonospora cubensis, and degenerate primers designed based on the conserved amino acid sequences of known plant disease-resistance genes. A polymorphic cDNA fragment which we named rap-19 was cloned and sequenced. The Open Reading Frame （ORF） of this product comprised of 510 base pairs which encodes DNA or RNA-binding protein with 170 amino acids. The putative amino acid sequence of mp-19 appeared highly homologous with those of NBS-type resistant-genes isolated from other plants. Southern blot indicated that the melon genome contained more than 3 copies of rap-19. The obvious expression differences detected by semi-quantitative RT- PCR could be observed between resistant-line Huangdanzi and susceptible-line Jiashi after Pseudoperonospora cubensis infection, which implied that mp-19 gene may be related to the resistance of downy mildew in melon.

Analysis of LMW-GS,α-and γ-Gliadin Gene Coding Sequences from Triticum macha

Novel LMW-GS （low molecular weight glutenin subunit）,α- and γ-gliadin from Triticum macha accessions were characterized via genomic PCR, which can do favor to improve the wheat quality. The complete coding regions of two α-gliadin, two γ-gliadin and two LMW-GS gene sequences, which designed as Gli-Mal, Gli-Ma2, Gli-Mrl, Gli-Mr2, Glu-LM1 and Glu-LM2, encoded the mature proteins with 307, 241, 348, 302, 474 and 377 amino acid residues, respectively. Gli-Mal and Gli-Ma2 were recognized as pseudogenes due to the in-frame stop codons. The amino acid sequences deduced from these gene sequences were characterized with the typical structure of α- or γ-gliadin or LMW- m type proteins with the exception of Gli-Ma2. Phylogenetic analysis showed Gli-Mal was closely related to those from T. aestivum, whereas Gli-Ma2 seemed to be more homologous with the gene sequences from Dasypyrum breviaristatum. Gli-Mrl was closely related to those from T. turgidum ssp. dicoccoides, while Gli-Mr2 was the nearest to those from T. aestivum. Glu-LM1 was closely related to those from Aegilops tauschii, whereas GIu-LM2 seemed to be more homologous with those from T. durum.

Vitis amuerensis CBF3 Gene Isolation,Sequence Analysis and Expression

The full length cDNA sequence of CBF3 （CRT/DRE-binding factor） was cloned from Vitis amurensis by reverse transcription polymerase chain reaction （RT-PCR） using the primers designed based on CBF genes available in GenBank. Sequence analysis showed that the gene had 854 bp long and its coding sequence contained 720 bp, encoding a protein with 239 amino acids and an AP2 structural domain. The molecular mass of CBF3 was predicted to be 25.9 kDa and its theoretical isoelectric point was 7.02 and aliphatic index was 59.29. The average hydropathicity of the protein was -0.551. The tertiary structures of CBF3 were also analyzed. The prokaryotic expression vector pGEX-4T-CBF3 containing CBF3 gene was constructed and CBF3 fusion protein （52 kDa） was produced in Escherichia coli after induction with 1 mmol L-1 IPTG. Further studies are needed to evaluate its potential application for improving plant resistance to cold and other stress condition such as drought and salinity.

Isolation and Sequence Analysis of HMW Glutenin Subunit 1Dy10.1 Ecoding Gene from Xinjiang Wheat (Triticum petropavlovskyi Udacz. et Migusch)

A novel HMW glutenin subunit gene 1Dy10. 1 was isolated and characterized from Xinjiang wheat （Triticum petropavlovskyi. Udacz. et Migusch） accession Daomai 2. The complete open reading frame （ORF） of 1Dy10. 1 was 1 965 bp, encoding 655 amino acids. The numbers and distribution of cysteines in 1Dy 10.1 were similar to those of 1Dy10 and other y-type subunits. In the N-terminal of 1Dy 10.1, an amino acid was changed from L （leucine） to P （proline） at position 55. The repetitive domain of 1Dy10.1 differed from those of known HMW subunits by substitutions, insertions or/and deletions involving single or more amino acid residues. In the repetitive domain of subunit 1Dyl 0.1, the deletion of tripeptide GQQ in the consensus unit PGQGQQ resulted in the appearance of the motif PGQ that have not been observed in other known y-type HMW subunits. In comparison with the subunit 1Dy 12, a deletion of dipeptide GQ, which occurred in subunit IDy10, was also observed in subunit 1Dy10.1. The cloned IDylO. 1 gene had been successfully expressed in Escherichia coli, and the expressed protein had the identical mobility with the endogenous subunit IDy10.1 from seed.

A new Multilocus Sequence Analysis Scheme for Mycobacterium tuberculosis

Objective Tuberculosis remains one of the most serious infectious diseases in the world. In this study, a scheme of Mycobacterium tuberculosis （M. tuberculosis） multilocus sequence analysis （MLSA） was established for the phylogenetic and epidemiology analysis. Methods To establish the scheme of M. tuberculosis MLSA, the genome of H37Rv, CCDC5079 and CCDC5180 were compared, and some variable genes were chosen to be the MLSA typing scheme. 44 M. tuberculosis clinical isolates were typed by MLSA, IS6110-RFLP, and soligotyping, to evaluate the MLSA methods. Results After comparison of the genome, seven high discrimination gene loci （recX, rpsL, rmlC, rpmG1, mprA, gcvH, ideR） were chosen to be the MLSA typing scheme finally. 11 variable SNP sites of those seven genes were found among the 44 M. tuberculosis isolate strains and 11 sequence types （STs） were identified. Based on the Hunter-Gaston Index （HGI）, MLSA typing was not as good for discrimination at the strain level as IS6110-RFLP, but the HGI was much better than that of spoligotyping. In addition, the MEGA analysis result of MLSA data was similar to spoligotyping/PGG lineage, showing a strong phylogenetic signal in the modern strains of M. tuberculosis. The MLSA data analysis by eBURST revealed that 4 sequence types （ST） came into a main cluster, showing the major clonal complexes in those 44 strains. Conclusion MLSA genotyping not only can be used for molecular typing, but also is an ideal method for the phylogenetic analysis for M. tuberculosis.

Cloning and Sequence Analysis of Expansin Genes from Litchi chinensis Fruit

Using PCR degenerate primers, designed with reference to the sequences of the conserved amino acids of known expansins, to amplify cDNA fragments in litchi fruit by RT-PCR, two different cDNA fragments , named as Lc-Exp1 and Lc-Exp2 , were cloned. Lc-Exp1 and Lc-Exp2 was respectively composed of 531 bp encoding 177 amino acids and 537 bp encoding 179 amino acids. Eight cysteine residues and three tryp-tophan residues, which is supposed to be the characteristics of expansins, are conserved in both Lc-Exp1 and c-Exp2. In addition, the homology between the two expansins is 71. 6% at nucleotide acid sequences and 76.3% at amino acid sequences. The homology of Lc-Exp1 with Fa-Exp2 or Pp-Exp1 was 92.7% or 92.1%, but that of Lc-Exp2 with Fa-Exp2 or Pp-Exp1 was only 77. 4% or 76.3% at amino acid sequences.

Cloning and Sequence Analysis of a Novel Cold-Adapted Lipase Gene from Strain lip35 (Pseudomonas sp.)

A combination method of the usual-PCR and reverse-PCR for the cloning of a novel lipase gene directly from the total genomic DNA of strain lip35 （Pseudomonas sp.） is described, whereby a lipase gene （lip） was cloned directly from genomic DNA. The sequence data have been deposited in the GenBank and EMBL data bank with the accession number EU414288. The nucleotide sequence showed a major open reading frame encoding a 59-kDa protein of 566 amino acid residues, which contained a lipase consensus sequence GXSXG. The lipase lip had 74 and 70% homologies with the lipases of an uncultured bacterium and P. fluorescens PfO-1, respectively, but it did not show any overall homology with lipases from other origins. The functional lipase was obtained when the lip gene was expressed in Pichia pastoris GS115.

Cloning and sequence analysis of the partial sequence of the rbcL from Bryopsis hypnoides

The partial sequence of the rbcL from Bryopsis hypnoides, including the sequences of the upstream, extron and partial intron, was amplified by PCR and their sequences were determined. With Spinacia oleracea as the outgroup, neighbor-joining method and maximum parsimony method were used respectively to build phylogenetic trees according to the rbcL exon sequence among 13 species that were the typical species of six phyla. Two kinds of trees showed clearly that there were two groups among those species, the green lineage and the non-green lineage. And the relationships of algae in the green lineage were similar in the two trees but those in the non-green lineage were not consistent. Analysis of codon preference indicated that the codon preference of the rbcL exon of Bryopsis hypnoides distinctly differed from that of the relevant sequence of photosynthetic bacteria.

Aequorea taiwanensis n. sp. (Hydrozoa,Leptomedusae) and mtCOI sequence analysis for the genus Aequorea

Nine species of Prionospio complex are recorded from China＇s waters,including one new species and six newly recorded species.Prionospio（Prionospio） pacifica sp.nov.,is characterized by having first and forth pairs of branchiae pinnate,second and third pairs of apinnate,ventral crest on Setiger 9 and dorsal crests on Setigers 10-25.Apoprionospio kirrae（Wilson,1990）,Prionospio（Aquilaspio） convexa Imajima,1990,Prionospio（Minuspio） multibranchiata Berkeley,1927,Prionospio（Prionospio） bocki Sderstrm,1920,Prionospio（Prionospio） dubia Maciolek,1985 and Prionospio（Prionospio） paradisea Imajima,1990 are recorded for the first time from China＇s waters.

Molecular Cloning and cDNA Sequence Analysis of Two New Lepidopteran OR83b Orthologue Chemoreceptors

The aim of this study was to isolate the full-length cDNA sequences of an unusually highly conserved olfactory receptor （orthologue to the Drosophila melanogaster DOR83b） from the antennae of Spodoptera exigua and S. litura by using reverse transcription-polymerase chain reaction （RT-PCR） and rapid amplification of cDNA ends （RACE） methods. Bioinformatics methods were used to further analyze the cDNA sequences and putative amino acid sequences. The two full-length cDNA sequences from olfactory receptor （OR） of male S. exigua and S. litura were named as SexiOR2 and SlitOR2, respectively. SexiOR2 and SlitOR2 consisted of nucleotide sequence of 1 906 and 2 483 bp, respectively, and both with deduced amino acid sequences of 473 residues. The sequence analysis indicated that the deduced amino acid sequences of the cDNA shared the high homologies with OR83b orthologue chemoreceptor sequences from previously reported moths, implying that the cDNA sequences were of OR83b orthologue chemoreceptor genes.

HA Gene Variation Analysis of H9N2 Sub-type Avian Influenza Virus from Three Strains in Different Times

HA Gene of H9N2. sub-type avian influenza virus from three strains in different times was amplified, purified and then sequenced. The results of its sequence analysis showed that the whole length of the amplified HA Gene was 1 683 bp, encoding 560 amino acids. The amino acid sequence of three virulent strains at cleavage site was R-S-S-R, which was low-pathogenicity strain. According to the amino acid sequence of the isolated strains, there were 7 potential glycosylation sites, and the receptor-binding site was the specific sequence of the avian-derived influenza virus. Amino acids on the left edge of receptor-binding site were all NGQQG, while amino acids on the right edge of receptor-binding site were GTSKA. From the comparative sequence analysis of HA Gene from some referenced strains, the results indicated that nucleotide and amino acid homology between isolated strains and referenced strains was higher. Evolutionary tree analysis showed that three strains were all Eurasian species, and there was a close relationship with the representative strains of A / duck / Hong Kong/Y280/97.

Gene cloning and sequence analysis of the cold-adapted chaperones DnaK and DnaJ from deep-sea psychrotrophic bacterium Pseudoalteromonas sp. SM9913

Pseudoalteromonas sp. SM9913 is a phychrotmphic bacterium isolated from the deep-sea sediment. The genes encoding chaperones DnaJ and DnaK of P. sp. SM9913 were cloned by normal PCR and TAIL - PCR （GenBank accession Nos DQ640312, DQ504163 ）. The chaperones DnaJ and DnaK from the strain SM9913 contain such conserved domains as those of many other bacteria, and show some cold-adapted characteristics in their structures when compared with those from psychro-, meso-and themophilic bacteria. It is indicated that chaperones DnaJ and DnaK of P. sp. SM9913 may be adapted to low temperature in deep-sea and function well in assisting folding, assembling and translocation of proteins at low temperature. This research lays a foundation for the further study on the cold-adapted mechanism of chaperones DnaJ and DnaK of cold-adapted microorganisms.

Isolation and Sequence Analysis of NSP2, ORF3 and ORF5 of PRRSV XH-GD Strain from Guangdong Province

The diseased samples collected from Guangdong Province were inoculated to Marc-145 cells, PRRSV-specific cytopathogenic effects （CPE） such as cell aggregation, cell shrinkage and cell exfoliation were observed and a PRRSV strain XH-GD was obtained. By using primers designed in accordance with the pub- lished gene se^lences of PRRSV in GenBank, NSP2, ORF3 and ORF5 fragments were amplified by reverse transcription polymerase chain reaction and analyzed by sequence aligment. The results demonstrated that PRRSV strain XH-GD belonged to the North American genotype and the NSP2 gene contained discontinuous de- letions of 30 amino acids. NSP2, ORF3 and ORF5 genes of XH-GD shared 83.3% -98.9%, 88.6% -99.2% and 88.1% -99.2% nucleotide homology, and 76.8% -98.3%, 83.7% -98.8% and 88.1% -99.2% amino acid homology with HUB1, NX06, BJsy06, VR-2332, HB-1（sh）2002, HB-2（sh）2002, CH-1a and RespPRRS MLV, respectively; however, NSP2, ORb3 and ORF5 genes of XH-GD shared only 52.9%, 65.0% and 64. 3% nucleotide homology, and 31.3%, 57.5% and 58.9% amino acid homology with LV, respectively. Phylogenetic analysis revealed that XH-GD had a closer relationship with HUB1, NX06, BJsy06, VR-2332, HB-1 （sh） 2002, HB-2 （sh） 2002, CH-la and RespPRRS MLV strains compared with LV strain.

Genetic relationship between Neobenedenia girellae and N. melleni inferred from 28S rRNA sequences

The fragments of 350 bp in 28S rRNA from the closely related monogenea of trematoda, Neobenedenia girellaeand N. melleni are obtained by polymerase chain reaction (PCR) amplified using a couple of special primers andthen sequenced. The results show that the comparison of 28S rRNA sequences, with only a base varying in 337bp accounting for 0.3% genetic difference, from the relative species N. girellae and N. melleni parasitized on thedifferent fishes in different farms displays that they possess a very high genetic similarity of 99.7%, higher thanthat of 99.41% for the single species N. melleni sampled in different areas, and the intraspecific divergence of N.melleni is 0.59%. Meanwhile, the interspecific differences between the two Neobenedenia and three Benedenia (i.e., B. lutjani, B. rohdei and B. seriolae) range from 2.08% to11.73%. In addition, UPGMA and MP molecularphylogenetic trees are constructed and proved to be consistent with each other. Though the morphologicalcharacteristics and the results of genetic diversity for the two Neobenedenia show a high similarity, whether theybelong to a single species or not are still undefined, and the more genes of them should be further investigated, incombination with the systematical and detailed morphological study.

Sequence Analysis of Polypeptide by Mass Spectrometry

The method described in this work provides a sensitive and fast technique for investigating the primary structure of peptides with molecular weight up to 3340 amu. Usually, the metastable ion kinetic energy spectra (MIKES) and collisional activated decomposition (CAD) spectra provide complementary information for the FAB mass spectra, the MIKES and CAD spectra generally contain high-mass sequence ions.

Cloning and analysis of cross-intron genomic gene encoding ACO in Paeonia suffruticosa Andr.

The last step of ethylene biosynthesis in higher plants is to convert 1-aminocyclopropane-1-carboxylic acid （ACC） to ethylene by ACC oxidase （ACO）. In our investigation, a cross-introns genomic DNA gene encoding ACC oxidase, PsgACO, was isolated from Paeonia suffruticosa. It revealed that PsgACO （FJ855434） has 1281 bases, containing four exons and three introns, en- coding 312 amino acids. The four exons stretched from 1 to 105, 217 to 434, 592 to 925 and 1000 to 1281 bases. A splicing junction sequence of all the exon-introns conformed to the GT-AG rule in the cross-intron genomic DNA sequence of the ACO gene. PsgACO showed high homology to many characterized ACC oxidases both at the nucleic acid and amino acid levels. As well, twelve amino acid residues were conserved among many ACOs from other species. A phylogenetic tree analysis indicated that the amino acid of ACOs is quite conserved among the different eudicots. The phylogenetic tree showed that both the tree peony and herbaceous peony are quite isolated taxa. Bioinformatic analysis showed that the molecular weight of ACO is 35.29 kD, with a theoretical pI of 5.25. It is a non-secrete, stable hydrophilic protein, located in the cytoplasm.

Sequence Analysis on Interleukin-2 Gene and Interleukin-6 Gene in a Hybrid Pig

[ Objective] To understand the functions of interteukin-2 （IL-2） and interleukin-6 （IL-6） in immune response. [ Method] Peripheral lymphocytas were isolated from a hybrid pig （ Duroc x Landrace x Shandong local pig） and stimulated with canavalin A in vitro. With total RNA as templates, the IL-2 and IL-6 cDNA were amplified by the RT-PCR and sequenced, respectively. [Result] The sequence of IL-2 gene had 100.0% nucleotide homology to the published IL-2 sequences. The sequence of IL-6 gene had 99.8% -100.0% nucleotide homology to the published IL-6 sequences, and the amino acid homology was 99.1% -100.0%. [ Conclusion] NO great variation of the IL-2 gene and IL-6 gene is observed in the hybdd pig, and these results provide a basis for research about functions of IL-2 and IL-6 protein.