Unraveling the seed endosperm proteome of the lotus (Nelumbo nucifera Gaertn.) utilizing 1DE and 2DE separation in conjunction with tandem mass spectrometry

Prophylactic effects of alkaloids from Ba lotus seeds on L-NNA-induced hypertension in mice

Alkaloids from Ba lotus seeds (ABLS) are a kind of important functional compounds in lotus seeds. The present study was designed to determine its hypertension prophylactic effects in the L-NNA-induced mouse hypertension model. The mice were treated with ABLS, the serum and tissues levels of NO, MDA, ET-1, VEGF, and CGRP were determined using the experimental kits, the mRNA levels of various genes in the heart muscle and blood vessel tissues were further determined by RT-PCR assay. ABLS could reduce the systolic blood pressure (SBP), mean blood pressure (MBP), and diastolic blood pressure (DBP), compared to that of the model control group. After ABLS treatment, the NO (nitric oxide) contents in serum, heart, liver, kidney and stomach of the mice were higher than that of the control mice, but the MDA (malonaldehyde) contents were lower than that of the control mice. The serum levels of ET-1 (endothelin-1), VEGF (vascular endothelial growth factor) were decreased after ABLS treatment, but CGRP (calcium gene related peptide) level was increased. The ABLS treated mice had higher mRNA expressions of HO-1, nNOS, and eNOS and lower expressions of ADM, RAMP2, IL-1β, TNF-α, and iNOS than the control mice. Higher concentration of ABLS had greater prophylactic effects, which were close to that of the hypertension drug captopril. These results indicated the hypertension prophylactic effects of ABLS could be further explored as novel medicine or functional food in the future.

Metabolomic and Proteomic Profiles Reveal the Dynamics of Primary Metabolism during Seed Development of Lotus (Nelumbo nucifera)

Sacred lotus (Nelumbo nucifera) belongs to the Nelumbonaceae family. Its seeds are widely consumed in Asian countries as snacks or even medicine. Besides the market value, lotus seed also plays a crucial role in the lotus life cycle. Consequently, it is essential to gain a comprehensive understanding of the development of lotus seed. During its development, lotus seed undergoes cell division, expansion, reserve accumulation, desiccation, and maturation phases. We observed morphological and biochemical changes from 10 to 25 days after pollination (DAP) which corresponded to the reserve synthesis and accumulation phase. The volume of the seed expanded until 20 DAP with the color of the seed coat changing from yellow-green to dark green and gradually fading again. Starch and protein rapidly accumulated from 15 to 20 DAP. To further reveal metabolic adaptation, primary metabolites and proteins profiles were obtained using mass spectrometry based platforms. Metabolites and enzymes involved in sugar metabolism, glycolysis, TCA cycle and amino acid metabolism showed sequential dynamics enabling the clear separation of the different metabolic states during lotus seed development. The integration of the data revealed a highly significant metabolic switch at 15 DAP going through a transition of metabolically highly active tissue to the preparation of storage tissue. The results provide a reference data set for the evaluation of primary metabolism during lotus seed development.

Immature Seed Endosperm and Embryo Proteomics of the Lotus (Nelumbo Nucifera Gaertn.) by One-Dimensional Gel-Based Tandem Mass Spectrometry and a Comparison with the Mature Endosperm Proteome

Lotus (Nelumbo nucifera Gaertn.) seed proteome has been the focus of our studies, and we have recently established the first proteome dataset for its mature seed endosperm. The current study unravels the immature endosperm, as well as the embryo proteome, to provide a comprehensive dataset of the lotus seed proteins and a comparison between the mature and immature endosperm tissues across the seed's development. One-dimensional gel electrophoresis (SDS-PAGE) linked with tandem mass spectrometry provided a protein inventory of the immature endosperm (122 non-redundant proteins) and embryo (141 non-redundant proteins) tissues. Comparing with the previous mature endosperm dataset (66 non-redundant proteins), a total of 206 non-redundant proteins were identified across all three tissues of the lotus seed. Results revealed some significant differences in proteome composition between the three lotus seed tissues, most notably between the mature endosperm and its immature developmental stage shifting the proteins from nutrient production to nutrient storage.