Characterization of natural peptides in Pheretima by integrating proteogenomics and label-free peptidomics

Pheretima,also called“earthworms”,is a well-known animal-derived traditional Chinese medicine that is extensively used in over 50 Chinese patent medicines(CPMs)in Chinese Pharmacopoeia(2020 edition).However,its zoological origin is unclear,both in the herbal market and CPMs.In this study,a strategy for integrating in-house annotated protein databases constructed from close evolutionary relationship-sourced RNA sequencing data from public archival resources and various sequencing algorithms(restricted search,open search,and de novo)was developed to characterize the phenotype of natural peptides of three major commercial species of Pheretima,including Pheretima aspergillum(PA),Pheretima vulgaris(PV),and Metaphire magna(MM).We identified 10,477 natural peptides in the PA,7,451 in PV,and 5,896 in MM samples.Five specific signature peptides were screened and then validated using synthetic peptides;these demonstrated robust specificity for the authentication of PA,PV,and MM.Finally,all marker peptides were successfully applied to identify the zoological origins of Brain Heart capsules and Xiaohuoluo pills,revealing the inconsistent Pheretima species used in these CPMs.In conclusion,our integrated strategy could be used for the in-depth characterization of natural peptides of other animal-derived traditional Chinese medicines,especially non-model species with poorly annotated protein databases.

Changes of the Content and Antioxidant Activity of Natural Peptides in Germinated Soybeans

[ Objective] This study aimed to investigate the content and antioxidant activity of natural peptides in various soybean sprouts during the germination process. [Method] By using black soybean sprouts, yellow soybean sprouts and green soybean sprouts as raw materials, the content, DPPH ·clearance rate, OH · clearance rate and reduction capacity of natural peptides in various soybean sprouts at different germination time were determined, to evaluate the antioxidant capacity of natural peptides and compare it with that of Vc. [ Result] The results showed that the contents of natural peptides in black soybean sprouts, yellow soybean sprouts and green soybean sprouts varied at different germination time. To be specific, the content of natural peptides in black soybean sprouts reached the maximmn of 0. 194 mg/g at 2 d post-germination; the content of natural pepfides in yellow soybean sprouts reached the maximum of 0.231 mg/g at 2 d post-germination; the content of natural peptides in green soybean sprouts exhibited a negative correlation with the germination time, which reached the maximum of 0. 164 mg/g at 1 d post-germination. [ Conclusion] According to the determination of DPPH ·clearance rate, OH ·clearance rate and reduction capacity of natural peptides in three varieties of soybean sprouts, natural peptides in yellow soybean sprouts possess the highest antioxidant activity, followed by those in black soybean

To resolve recent natural immune defense effects of antimicrobial peptides in the gastrointestinal tract

The human gut is the normal habitat of a lot of microorganisms; in the long process of evolution they have developed a symbiotic relationship with the host. Under normal circumstances they do not damage the health, which totally owes to the barrier functions of the integral intestinal mucosa. Intestinal lnucosal barriers are mainly composed of four parts： mechanical barrier, immune barrier, chemical and biological barrier. Each of these functions has corresponding structural basis, an important barrier to prevent harmful substances and pathogens in the gut into the inner environment of the body, and to maintain a stable internal environment.

Immunomodulation of polypeptides fromChlamys farreri in vitro

The aim of this study was to investigate the effects of polypeptides from Chlamys farreri （PCF） on immunoeytes or immunocytes treated with dexamethasone （DEX） in vitro. After incubating immunoeytes with 25 mg/L PCF or/and DEX for a given time, the proliferative response of thymocytes and splenoeytes to ConA were measured bv MTF assay; the subpopulations of thymocytes and splenic T lymphoeytes was analyzed by flow cytomety; the cytotoxicity of natural killer cells was measured by Llactate dehydrogenase （LDH） assay; the phagocytosis of rat peritoneal macrophages was measured by Neutral red assay and the Bel-2 protein expression of macrophages was detected by imrnunocytoehemical stain. The proliferative ability of rat thymocytes and splenocytes induced with ConA was enhanced and the depression of lymphoproliferation caused by DEX was reversed by PCF. The percentages of mouse thymic L3 T4^- Lyt-2^- and Lyt-2^＋ subpopulations and splenic Lyt-2 ^＋ cells were decreased and the percentage of splenic L3 T4^ ＋ cells was increased by PCF. The NK cytotoxicity, phagocytosis of macraphages and Bcl-2 protein expression of macrophages were enhanced and the decrease of NK cytotoxicity and Bel-2 protein expression of maerophages caused by DEX were reversed by PCF. PCF could not only enhance the normal immunity function, but also reverse the imrnunosuppression induced by DEX.

Complex peptide natural products: Biosynthetic principles, challenges and opportunities for pathway engineering

Complex peptide natural products exhibit diverse biological functions and a wide range of physico-chemical properties.As a result,many peptides have entered the clinics for various applications.Two main routes for the biosynthesis of complex peptides have evolved in nature:ribosomally synthesized and post-translationally modified peptide(RiPP)biosynthetic pathways and non-ribosomal peptide synthetases(NRPSs).Insights into both bioorthogonal peptide biosynthetic strategies led to the establishment of universal principles for each of the two routes.These universal rules can be leveraged for the targeted identification of novel peptide biosynthetic blueprints in genome sequences and used for the rational engineering of biosynthetic pathways to produce non-natural peptides.In this review,we contrast the key principles of both biosynthetic routes and compare the different biochemical strategies to install the most frequently encountered peptide modifications.In addition,the influence of the fundamentally different biosynthetic principles on past,current and future engineering ap-proaches is illustrated.Despite the different biosynthetic principles of both peptide biosynthetic routes,the arsenal of characterized peptide modifications encountered in RiPP and NRPS systems is largely overlapping.The continuous expansion of the biocatalytic toolbox of peptide modifying enzymes for both routes paves the way towards the production of complex tailor-made peptides and opens up the possibility to produce NRPS-derived peptides using the ribosomal route and vice versa.

A new technique helps to uncover unknown peptides and disinfection by-products in water

Environmental water samples can be extremely complex,with potentially thousands of molecules that can derive from natural organic matter（NOM）and thousands that derive from anthropogenic contaminants.As complex as these samples are,drinking water can be even more complex.Due to disinfectants that are used to treat drinking water（e.g.,chlorine,chloramines,