Effect of Duodenal Soybean Small Peptides Infusion on Mammary Uptake of Amino Acid and Expression of APN in Lactating Goat

The aim of this study was to investigate the effect of duodenal infusion of soybean small peptides(SSP) on mammary uptake of amino acids(AA).Eight Chinese Saanen goats with duodenal fistulae and catheters were used in a crossover design trial.Goats were infused with 0,60,120,180 g/d SSP.The experimental period lasted for 14 d.The results showed:1) milk protein yield and content were increased,with the increment in milk protein yield being significant(P【0.05).Milk fat yield and content were decreased with the increased amount of SSP infused(P【0.05).2) Mammary plasma flow was not changed(P】0.05) by SSP infusion though the average was slightly higher.Mammary plasma flow/milk yield was decreased by SSP infusion and there was significant difference between the 120 g/d treatment and the control(P【0.05).3) Compared with the control treatment,uptakes of most free amino acids were increased in the 60 and 120 g/d treatments,but decreased by the 180 g/d treatment.The uptakes of all peptide-bound essential amino acids(PB-EAA) were increased except for PB-Ile.Uptake of PB-Val,PB-Leu, PB-Phe,PB-Thr,PB-Met and PB-Lys was highest in the 120 g/d treatment.Among the peptide-bound nonessential amino acids(PB-NEAA),uptake of PB-Ser,PB-Tyr,and PB-Pro was increased(P【0.05) while that of PB-Gly was decreased(P】0.05).4) With the exception of Lys,secretion of all essential AA(EAA) was increased by SSP infusion from 0-120 g/d(P【0.05),while in the 180 g/d treatment the increase was not significant and was lower than that in the 120 g/d treatment.5) The expression of APN was increased by SSP;in the 60,120,180 g/d treatments expression was 13.55-,18.69-,and 10.01-fold over that of the controls.Conclusion:SSP might be used as substrates for milk protein synthesis by mammary gland,and can increase synthesis and secretion of milk protein.There was reason to believe that uptake and use of AA was either saturated or inhibited at high levels of infusion of SSP.Increased APN expression with infusion of SSP related to mammary uptake of PBAA by mammary gland,which suggested that APN was one of the peptidases regulating use of AA from small peptides in mammary tissue.

Theoretical Study of the Sensitivity-Improvement Effect of Phosphoryl Group in Mass Spectrometry of Small Peptides

It was found that phosphorylation of small peptide could improve the sensitivity in mass spectrometry. Density functional theory calculations showed that the energy for the protonation of N-(O,O'-dimethyl) phosphoryl glycylglycine is lower than that of glycylglycine. These could help to understanding the experimental results.

Shining in the dark:the big world of small peptides in plants

Small peptides represent a subset of dark matter in plant proteomes.Through differential expression patterns and modes of action,small peptides act as important regulators of plant growth and development.Over the past 20 years,many small peptides have been identified due to technical advances in genome sequencing,bioinformatics,and chemical biology.In this article,we summarize the classifi-cation of plant small peptides and experimental strategies used to identify them as well as their potential use in agronomic breeding.We review the biological functions and molecular mechanisms of small peptides in plants,discuss current problems in small peptide research and highlight future research directions in this field.Our review provides crucial insight into small peptides in plants and will contribute to a better understanding of their potential roles in biotechnology and agriculture.

Novel Rearrangement of Small Peptides in Electrospray Ionization Tandem Mass Spectrometry

Electrospray ionization mass spectrometry (ESI-MS) is a powerful method for sequencing peptides. A novel fragmentation pattern with the loss of a neutral fragment of 45 Da was observed with the dipeptides, tripeptides, tetrapeptides and pentapeptides containing phenylalanine or histidine residues. A novel rearrangement reaction with the extrusion of a formamide piece was studied and the rearrangement mechanism was proposed and confirmed by deuterium labeling experiments with ESI-MSn and high-resolution mass spectrometry. These findings are poten-tially helpful in identifying the specific sequence pattern in the peptide sequencing.

Small peptides, big roles-RALFs regulate pollen tube growth and burst in plant reproduction

In flowering plants,the pollen grain generates a pollen tube to deliver two immotile sperm cells to the embryo sac for double fertilization.After landing on the stigma of the pistil,the pollen grain hydrates and germinates to produce a pollen tube,which penetrates the style and grows into the transmitting tract.The pollen tube then emerges onto the surface of the septum,grows along the funiculus,responds to the attraction signals from the synergid cells of the embryo sac and targets the ovule micropyle.

Protective Effect of Wheat Peptides Against Small Intestinal Damage Induced by Non-Steroidal Anti-Inflammatory Drugs in Rats

Non-steroidal anti-inflammatory drugs（NSAIDs） were able to produce tissue damage and oxidative stress in animal models of small intestinal damage. In this study, the putative protective effect of wheat peptides was evaluated in a NSAID-induced small intestinal damage model in rats, different doses of wheat peptides or distilled water were administered daily by intragastric administration for 30 d until small intestinal damage was caused. Before sacrificing, NSAIDs（aspirin and indomethacin） or physiological saline were infused into the digestive tract twice. Wheat peptides administration reduced edema and small intestinal damage, and significantly decreased the level of tumor necrosis factor（TNF）-α in mucous membrane of small intestine. Oxidative stress was significantly increased after NSAID infusion and was reduced by wheat peptides. Wheat peptides increased glutathione peroxidase（GSH-Px） activity in mucous membrane of small intestine. μ-Opioid receptor mRNA expression decreased more significantly in wheat peptides treated rats than in the model control group. Overall, the results suggest that non-steroidal anti-inflammatory drugs induced small intestinal damage in rats and wheat peptides administration may be an effective tool for protecting small intestinal tissue against NSAID-induced small intestinal damage and oxidative stress.

Discussion of the Composition of Jaboticaba in Different Processes

This study discusses the composition analysis and comparison of Jaboticaba under different processing conditions for fermented liquid, jam, fruit powder, and fruit vinegar. The differences and comparison of the contents of total polyphenols, anthocyanins, resveratrol, superoxide dismutase, small molecular peptides and ellagic acid in their products were analyzed. After analysis and comparison of results, the content of total polyphenols was found to be the highest 44.82 ± 0.89 (mg/g) after being fermented directly from fresh fruit. The fresh fruit was dried at low temperature and ground into powder, with a maximum ellagic acid content of 12.799 ± 0.12 (mg/g). Fresh fruit was then made into jam, with the highest anthocyanin content of 57.39 ± 1.20 (mg/g). The fruit vinegar was produced by fermentation. Except for the content of small molecule peptides, which was similar to the content of fermentation broth and fruit powder, they were 20.63 ± 1.61, 23.84 ± 2.51 and 20.52 ± 1.21 (mg/g), and the rest of the composition was not as good as other samples. In the fresh fruit fermentation broth samples, resveratrol was produced and detected, and its content was 2.14 (mg/L), while it was not detected in other samples, and a superoxide dismutase (SOD)-like enzyme was detected in the fresh fruit fermentation broth. The highest activity was 49002.5 units/mL. Jaboticaba is prepared using a fermentation broth processing method with fresh fruit, and its total polyphenol content is higher than that of fruit powder, jam, and fruit vinegar. The commercial value of Jaboticaba and the establishment of composition content data are relatively improved, which is more promising for the future.

A Study on Bioactivity of Corn Peptides with Low Molecular Weight(Ⅰ)Effect of an Intake of them on Alcohol Metabolism in Rats

This study aims at the effects of an intake of low molecular weight corn peptides(LMCPs) prepared from zein on alcohol metablism in rats. LMCPs(1.0 g/kg body weight) in 15% ethanol(10 mL/kg body weight) were given to Wister rats by intragastric gavage. The assay of blood ethanol was conducted by using the enzyme based assay kit. The amino acid analysis was made with an amino acid analyzer. The data of the animal experiments showed that LMCPs could accelerate the metabolism of alcohol in rats. In the control group, the blood ethanol concentration reached the maximum level of (827.0±77.3) mg/L after ethanol loading for 30 min, then gradually decreased. In contrast, the blood ethanol concentration only reached (527.25±47.0) mg/L after 30 min in the group of LMCPs taken. These results indicate that LMCPs could decrease ethanol concentration in blood rapidly.

Effects of Small Peptide Chelated Copper,Iron,Manganese and Zinc on Growth Performance,Chicken Quality and Antioxidant Capacity of Yellow Feather Broilers

[Objective]The paper was to study effects of small peptide chelated trace elements(copper,iron,zinc and manganese)on growth performance,chicken quality and antioxidant capacity of rapid yellow feather broilers.[Method]Three hundred one-day-old yellow feather broilers with similar body weight were selected and randomly divided into three treatments:inorganic trace element group(basal diet+inorganic trace elements),organic trace element group(basal diet+small peptide chelated trace elements)and compound group(basal diet+50%inorganic trace elements+50%small peptide chelated trace elements).There were 10 replicates per treatment and 10 chickens per replicate.The trial lasted for 63 d.[Result]①Compared to inorganic trace element group,average daily gain(ADG)of yellow feather broilers in organic trace element group was significantly increased over the whole period(P<0.05).②There was no significant difference in slaughter performance and immune organ indices among the three test groups(P>0.05).③There was no significant difference in breast muscle pH,chicken color,drip loss,and shear force among the three groups(P>0.05),but cooking loss of chicken breast in inorganic trace element group was 27.46%and 22.53%higher than those in organic trace element group and compound group,respectively(P<0.05).④MDA content in serum in organic trace element group was 15.61%lower than that in inorganic trace element group(P<0.05).[Conclusion]Complete substitution of inorganic copper,iron,zinc and manganese by small peptide chelated copper,iron,zinc,and manganese significantly increases ADG of broilers,improves quality of chicken breast,and enhances antioxidant capacity.

Research progress on the source,function and application of AMPs

Antibacterial peptide,also known as a host defense peptide,is a small molecular peptide that exhibits antibacterial activity.It disrupts the cell membrane structure of bacteria,leading to the release of internal contents and subsequent cell death,all without promoting the development of drug resistance in bacteria.It serves as a crucial component of the body’s innate immunity,forming the initial defense against the invasion of pathogenic microorganisms.However,the functionality of this small molecule peptide extends beyond this role.It also demonstrates positive effects in promoting organism growth,maintaining the balance of beneficial bacteria within organisms,combating cancer,enhancing immune function,and combating viruses,among other benefits.Additionally,it finds applications in biomaterials,food preservation,animal husbandry,and aquaculture.In summary,this small molecular peptide plays a significant role in various domains.

The relevance of dipeptides and tripeptides in the bioactivity and taste of dry-cured ham

Dry-cured ham has been described as a good source of bioactive peptides and taste-active compounds.Some of them are dipeptides and tripeptides that are released in a large amount from different muscle proteins due to the action of exopeptidases during the dry-cured ham processing.The potential of dipeptides and tripeptides to exert bioactivities and impart taste characteristics to dry-cured ham has been evaluated using the BIOPEP database,since in silico approaches are a time-and cost-effective alternative to empirical approaches.Most of the studied dipeptides and tripeptides showed ACE and DPP inhibitory activities as well as imparted bitter taste.In fact,more than one bioactivity and/or taste could be assigned to a given peptide sequence,and there could be a correlation between both,like ACE inhibitory and bitter EA,EI and LG peptides.Furthermore,several dipeptides such as EK,KP,LA,PL,PP,RG,and VE,among others,were found to be multifunctional(ACE and DPP IV inhibitory)which would be determined by their structure,sequence and amino acid composition.In silico analysis evidences the relevance of dipeptides and tripeptides in the bioactivity and taste of dry-cured hams,but further empirical assays including in vitro and in vivo studies are necessary to confirm such theoretical results.Possible degradation of the small peptides during gastrointestinal digestion and intestinal absorption as well as interactions with the food matrix could reduce their bioavailability and bioaccessibility,and modify their biological activities.

Genome-Wide Identification of Coding Small Open Reading Frames:The Unknown Transcriptome

The identification of the complete repertoire of functional peptides in a cell is ultimately essential for a systems-wide understanding of its behavior. There have indeed been a plethora of studies purportedly designed to this end. However, these studies in fact routinely overlook a potentially significant portion of their data that might encode for peptides that are smaller than 100 amino acids. This is largely owing to technical reasons associated with the difficulty of distinguishing, with statistical significance, a coding sequence of this length from a non-coding sequence. Recently, a growing number of studies have shown that there are indeed many small open reading frame(s ORF) encoded peptides that play important roles in a wide range of different biological processes.As such, there is now significant interest in methodologies that can be used to identify this drastically neglected portion of the cellular proteome. In this review, we introduce the presently known annotated s ORFs and describe the new strategies that have been used to determine the coding s ORFs, genome-wide.

Structural Insight into Recognition of Plant Peptid Hormones by Receptors

Secreted signaling peptides or peptide hormones play crucial roles in plant growth and development through coordination of cell-cell communication. Perception of peptide hormones in plants generally relies on membrane-localized receptor kinases （RKs）. Progress has recently been made in structural elucidation of interactions between posttranslationally modified peptide hormones and RKs. The structural studies suggest conserved receptor binding and activation mechanisms of this type of peptide hormones involving their conserved C-termini. Here, we review these structural data and discuss how the conserved mecha- nisms can be used to match peptide-RK pairs.