Biomedical subjects

Ningjia He

Publications and source records attributed to Ningjia He.

6 recordsLinked to original sources

PubMed2026

Precision UV-B irradiation for flavonoid biofortification in indoor-cultivated Morus nigra: Integrated multi-omics and molecular docking insights.

Precision application of UV irradiation represents an effective strategy for improving the quality of functional food crops under controlled environmental conditions. Morus nigra serves as a significant functional food resource in Xinjiang, with its leaves being rich in diverse bioactive compounds with nutritional and health-promoting properties. In this study, a low-dose UV-B treatment regimen was developed to enhance flavonoids in indoor-cultivated M. nigra without growth penalty. Multi-omics revealed a hormone shift (suppressed auxin vs. activated JA signaling). This triggered transcriptional reprogramming of PAL/4CL and CHS/CYP75B1, redirecting carbon flux towards flavonoid biosynthesis. Transient overexpression of MYB, NAC, and TIFY variants validated this regulatory network. The UV-B-induced NAC upregulated key genes and flavonoids, while different TIFY members showed diverse regulatory effects. Molecular docking predicted that the induced flavonoids had hypoglycemic, antioxidant, and anti-browning potential. This study indicates targeted UV-B as a green biofortification strategy for high-value crops in controlled environments.

Flavonoid biosynthesis↗

PubMed2006

Silkworm midgut proteins interacting with a hemolymph protease inhibitor, CI-8.

CI-8 is the chymotrypsin inhibitor in hemolymph from the silkworm, Bombyx mori. It occurs in the midgut at the spinning stage of larva, but little information on the mechanism of its uptake in the midgut is available. We found that two polypeptides interacting with CI-8 are in the midgut membrane, and we purified them using a biotinylated CI-8, viz., p29 and p60, having molecular sizes of 29 kDa and 60 kDa respectively. The structures of p29 and p60 were examined by N-terminal amino acid sequencing and peptide mass mapping, including tryptic digestion. p29 was highly similar to the matured 19G1-30K lipoprotein from hemolymph, but p60 was novel. Purified p29 was recognized by anti-19G1-30K antibody, and was confirmed to be similar to 19G1-30K. The antibody also neutralized the CI-8 binding ability of p29 in the midgut membrane. p29 and p60 are perhaps proteinaceous factors involved in the uptake of CI-8 into the midgut through the membrane.

Amino Acid Sequence↗

PubMed2005

Molecular and biochemical characterization of manganese-containing superoxide dismutase from the silkworm, Bombyx mori.

Superoxide dismutase (SOD) is responsible for the removal of superoxide anion from living organisms. In this study, cDNA encoding the manganese-containing SOD (MnSOD) from the silkworm, Bombyx mori, was isolated by reverse transcriptase-polymerase chain reaction and sequenced. The deduced amino acid sequence of the MnSOD revealed 62% identity to that of the Drosophila melanogaster; both were close to each other in a phylogenetic tree. The MnSOD was overproduced in Escherichia coli and purified. The internal structure of the recombinant MnSOD was confirmed by peptide mass fingerprinting method. The recombinant MnSOD facilitating the reduction reaction of superoxide anion retained 75% of its original activity after incubation at pH 4-11 for 24 h at 4 degrees C. Its activity was never affected by incubation at pH 7 for 30 min below 50 degrees C.

Amino Acid Sequence↗

PubMed2004

Overexpression in Escherichia coli and purification of recombinant CI-b1, a Kunitz-type chymotrypsin inhibitor of silkworm.

Present research provided an efficient approach to obtain large quantities of active recombinant CI-b1, a Kunitz-type chymotrypsin inhibitor of silkworm, Bombyx mori. The cDNA encoding mature CI-b1 was cloned into pDEST17 vector. Recombinant protein with hexa-histidine tag attached to the N-terminal of CI-b1 was expressed in Escherichia coli Origami B cells. It can be purified to homogeneity via the gel filtration chromatography on a Sephacryl S-200 column followed the affinity chromatography on a Ni-NTA column. The two sequential purification procedures yielded 4.3mg purified (His)(6)-tagged CI-b1 from 200ml of culture medium. Studies on (His)(6)-tagged CI-b1 revealed that three disulfide bonds were formed in the recombinant CI-b1 and the inhibitory properties of recombinant CI-b1 against alpha-chymotrypsin were similar to those of native CI-b1. Recombinant CI-b1 immobilized on Ni-NTA resin was used to detect the interactions occurring between the CI-b1 and its target factors.

Animals↗

PubMed2004

In vivo and in vitro interactions of the Bombyx mori chymotrypsin inhibitor b1 with Escherichia coli.

Various chymotrypsin inhibitors occur in the hemolymph of silkworm larvae. Interaction of chymotrypsin inhibitor b1 (CI-b1) with Escherichia coli was examined from the viewpoint of action against invading bacteria. Injection of dead E. coli cells into larva reduced the CI-b1 content of the hemolymph, suggesting in vivo binding of CI-b1 to the outer membrane of the cell. Results from incubation of E. coli in cell-free hemolymph in the presence or absence of lipopolysaccharide indicated that CI-b1 is the only CI bound to E. coli and that it interacts with lipopolysaccharide. CI-b1 formed a complex with lipopolysaccharide in vitro; the value of the dissociation constant was relatively large. Inhibitory activity of CI-b1 changed insignificantly in mixture with lipopolysaccharide. CI-b1 affected the growth of E. coli but never worked lethally. CI-b1 is speculated to be a mediator that scavenges intruding bacteria rather than a direct anti-bacterial factor. This is the first report confirming that CI-b1 is a lipopolysaccharide binding protein.

Animals↗

PubMed2003

Genomic structure and expression analysis of the gene encoding a silkworm basic Kunitz-type chymotrypsin inhibitor.

Kunitz-type chymotrypsin inhibitor CIb1 of silkworm Bombyx mori is a basic peptide consisting of 62 amino acid residues. To elucidate the mechanisms of transcriptional regulation of CIb1 gene expression, we cloned it for genomic structure analysis. CIb1 cDNA was used as a probe to screen a BAC sub-library. One positive clone containing the upstream sequences was isolated and the sequence result showed that CIb1 gene consists of three exons spaced by two introns. In the 5'-flanking region, consensus TATA and CCAAT boxes were identified. Other binding sites for transcription factors such as NF-kappaB, GATA, C/EBP, COUP-TF/HNF-4, RORalpha1, SRY, and HOXA3 were also detected. Southern blot analysis suggested a single copy of CIb1 gene in the silkworm genome. Northern blot analysis indicated that the expression of CIb1 gene is transcriptionally regulated during development and is apparently tissue-specific. The CIb1 mRNA was detected in fat body, ovary, trachea, and skin. We furthermore investigated the CIb1 expression profiles after LPS and E. coli injection. The fluctuations of CIb1 transcript in challenged larvae confirm our proposal that CIb1 is an immune responsible gene. According to our data, we discussed the transcriptional factors putatively responsible for the physiological role of CIb1 in the silkworm hemolymph.

Animals↗