16S rRNA Cloning and Identification of a Strain Isolated from Intestinal Tract of Rex Rabbit

This study was conducted to identify bacterial strain HeNan-001 isolated from intestinal tract of healthy rex rabbit. The strain was identified by gram staining, and OD600 values at different culture time were measured to develop a bacterial growth curve. The metabolic pathways of the bacterium using sugar in fermentation was identified with biochemical tubes. Total RNA of the strain was extracted, and total eDNA was obtained by Oligo （dT） method. Primers were designed using Primer 5.0 hip-software according to the 16S rRNA sequence published in GenBank, through cloning, ligation to vector PMD18T, construction of PMD18T/16S rRNA vector and transformation into DHSα, plasmid was extracted and sequenced, and the sequencing result was compared with sequences in NCBI followed by drawing of phylogenetic tree. The strain was verified to be double-stranded gram-positive cocci, which could ferment glucose, mannose, maltose and sorbitol, producing acids production, but failed to ferment sucrose, serum inulin and β-galactosidase. The phylogenetie tree analysis showed that the isolated bacterium shared the highest homology with an India isolate, and belongs to diplostreptococcus. This study provides significance experimental data and theoretical guidance for further development and utilization of the bacterial strain.

Phylogenetic Analysis of Morels Based on ITS and LSU Sequences

[Objectives]Fifty two strains were identified and phylogenetically analyzed to solve the current phenomenon of"synonym and homonym"in morels.[Methods]Based on the ITS and LSU sequences of ribosomal DNA,the collected 52 morel samples were sequenced,and BLAST alignment was performed by NCBI to construct phylogenetic trees.[Results]The collected morel strains were mainly divided into two major groups:namely black morel and yellow morel groups,of which the black morel group was most,mainly including Morchella sextelata,Morchella importuna,Morchella crassipes,and Morchella eximia.There were very few yellow morel strains,including M.crassipes and M.eximia.[Conclusions]This study lays a foundation for the classification and research of morel germplasm resources,and provides a powerful reference value for the research and production of high-quality morel strains.

Aspergillus cristatus LJSC.2006的分离鉴定及对茯茶发花品质的影响

This study investigated the effect of self-isolated and purified strain LJSC.2006 on the quality of Hunan Fu tea,a primary dark tea.Strain LJSC.2006 was identified as Aspergillus cristatus(Aspergillus cristatus LJSC.2006,GenBank accession number:MZ147025)through colony plate morphology,spore electron microscopy,and mycelial molecular marker identification.Sensory evaluation,biochemical composition analysis and head space solid phase microextraction/gas chromatography-mass spectrometry methods were applied to assess the flavor and aroma qualities of dark tea raw materials and fermented Jinhua loose tea.The results indicate that compared with the primary dark tea,the fermented loose tea sample exhibited a deeper color,the golden flowers,a richer fungus aroma,and a mellower taste.After fermentation by Aspergillus cristatus LJSC.2006,there was a decrease in the levels of flavor quality components such as tea polyphenols,soluble carbohydrates,free amino acids,flavonoids,ester-catechins,myricetin,quercetin and kaempferol.The aroma components,esters and aldehydes of the loose tea samples increased after fermentation.Styrene and cedrol were the common aroma components in the primary dark tea.(E)-linalool 3,7-oxide and acetophenone were the common aroma components in the fermented loose tea.Additionally,ten characteristic volatile components relative content were significantly increased,including methyl salicylate,(E,E)-2,4-heptadienal,(E)-linalool-3,7-oxide,(E)-furan oxidized linalool,(E)-2-nonanal,(E)-2-hexenal,(E,Z)-6-nonanal,acetophenone,(E)-2-nonanal,and methyl vanillate,which together contributed to the distinctive fungal fragrance of Jinhua loose tea.