Utilization of the waste aqueous phase from tea residue hydrothermal carbonization for preparing active food packaging films.

Hydrothermal carbonization (HTC) is an effective strategy for high-value utilization of tea residue (TR), and it was noticed the aqueous phase (AP) has not been extensively studied. This study aimed to investigate the chemical components and characteristics of the AP, and applied it in active food packaging films. The results showed that the total phenolic content of AP was 1.86 mg GAE/mL, and the main compounds in AP were organic acids, alcohols, and amino acids. The AP showed excellent antibacterial activity and antioxidant capacity. The active films were prepared using the casting method. The 4:7-AP/PVA film showed outstanding mechanical properties (tensile strength = 34.18 MPa, elongation at break = 458.67%), antioxidant ability (DPPH scavenging capacity 92.01%), antibacterial activity, water resistance and biocompatibility. The banana preservation test showed the AP/PVA films could successfully prolong the shelf-life of bananas and have the potential to be food packaging films.

The characterization and analysis of the compound hemostatic cotton based on Ca2+/poly (vinyl alcohol)/soluble starch-fish skin collagen.

Accidental bleeding is an unavoidable problem in daily life. To avoid the risk of excessive blood loss, it is urgent to design a functional material that can quickly stop bleeding. In this study, an efficient wound dressing for hemostasis was investigated. Based on the characteristics that Ca2+ and fish skin collagen (FSC) could activate the coagulation mechanism, hemostatic cotton was prepared by solvent replacement method using CaCl2, FSC, soluble starch (SS), and polyvinyl alcohol (PVA) as raw materials. The cytotoxicity test showed the Ca2+PVA/FSC-SS hemostatic cottons had good biocompatibility. The activated partial thromboplastin time (APTT) of Ca2+PVA/FSC-SS(4) was 35.34 s, which was 22.07 s faster than that of PVA/FSC-SS, indicating Ca2+PVA/FSC-SS mediated the endogenous coagulation system. In vitro coagulation test, Ca2+PVA/FSC-SS(4) could stop bleeding rapidly within 39.60 ± 5.16 s, and the ability of wound healing was higher than commercial product (Celox). This study developed a rapid procoagulant and hemostatic material, which had a promising application in a variety of environments.

Novel pH-responsive indicator films based on bromothymol blue-anchored chitin for shrimp freshness monitoring.

The cellulose nanofibers (CNFs) based pH-sensitive indicator films were developed by mixing guar gum (GG) with bromothymol blue-anchored chitin (BTB-Chitin) as an indicator to monitor shrimp freshness. The BTB-Chitin was prepared by grafting hydroxypropyltriethylamine groups (HPTA) to chitin first, then anchoring bromothymol blue (BTB) to prepare intelligent pH response BTB-Chitin. The 0.08 BTB-Chitin films had a good tensile strength of 11.76 MPa and the water contact angle values were 125°, which displayed obvious color response to pH buffers and acid base volatile gas. Besides, the homogeneous and flexible composite films showed good color stability and reversibility. The released amount of BTB was very low from the BTB-Chitin films in heptane and corn oil. The composite films had been degraded completely in 15 days in soil. The pH and volatile base nitrogen were measured to determine the degree decay of shrimp (Litopenaeus vannamei), and the prepared pH-sensitive films changed from yellow (fresh) to cyan (spoiled) with the freshness of shrimp decreased, indicating the BTB-Chitin films could detect the shrimp freshness in real-time and high visibility.

Preparation of a multifunctional silver nanoparticles polylactic acid food packaging film using mango peel extract.

As high-efficiency, safe, and low-drug resistant antibacterial agents, silver nanoparticles (AgNPs) have been widely applied in food and biomedicine. AgNPs was prepared using mango peel extract (MPE) as green and cheap reducing agent and stabilizer. In addition, a novel of preservative film material was developed with polylactic acid (PLA) as protective and substrate. AgNPs was characterized by XPS, XRD and TEM, and the size of AgNPs were in the range of 2.5-6.5 nm. The addition of AgNPs improved the mechanical properties of the film and its barrier ability to water vapor and oxygen. The film exhibited excellent antibacterial properties, and the inhibition rate against Escherichia coli and Staphylococcus aureus were above 95%. Furthermore, in terms of safety, the silver migration and cytotoxicity of the film met the relevant standards, and the shelf life of strawberries was significantly extended.

Protein Conjugation via SpyStapler-Mediated SpyTag/BDTag Coupling.

Genetically encoded peptide-protein coupling reactions, such as the SpyTag/SpyCatcher chemistry, are recent additions to the expanding toolbox of protein bioconjugation. The alternative three-component ligation system, e.g., SpyStapler-mediated SpyTag/BDTag coupling, retains most advantages of the Tag/Catcher chemistry, yet requires only two short peptide tags in the genetic fusion for side-chain ligation. Not only does this facilitate the construction of large protein conjugates directly from as-expressed protein components with minimal disruption to their function, but it also provides an entirely new mode of bioconjugation via mechanical bonding, which could impart additional functional benefits such as improved activity and enhanced stability to the conjugate. Such features are attractive for improving the pharmacokinetic performance of protein therapeutics. Herein we describe protocols for SpyStapler-mediated SpyTag/BDTag coupling for protein bioconjugation. © 2021 Wiley Periodicals LLC. Basic Protocol 1: Conjugation via isopeptide bond Support Protocol: Purification by size-exclusion chromatography Basic Protocol 2: Conjugation via mechanical bond.

The Associations between the Duration of Folic Acid Supplementation, Gestational Diabetes Mellitus, and Adverse Birth Outcomes based on a Birth Cohort.

This study aimed to examine the associations between the duration of folic acid (FA) supplementation, gestational diabetes mellitus (GDM), and adverse birth outcomes. A total of 950 mother-offspring pairs participated in the cohort study during 2015 in Changsha, China. The data were collected through home visits and perfected by maternal and child healthcare handbooks. Generalized linear models and stratified analyses were used for statistical analyses. The incidence of GDM in our cohort was 10.2%. FA supplementation for ≥3 months before pregnancy was associated with an increased risk of GDM (adjusted relative risk (aRR): 1.72; 95% CI: 1.17-2.53) and decreased risk of small-for-gestational-age (SGA) birth (aRR: 0.40; 95% CI: 0.18-0.88). In the group of FA supplementation for ≥3 months during pregnancy, GDM was associated with an increased risk of cesarean delivery (aRR: 1.36; 95% CI: 1.06-1.75) and macrosomia (aRR: 2.11; 95% CI: 1.06, 4.20), but the aRRs were lower than the RRMH 1.53 (95% CI: 1.01-2.34) and 2.43 (95% CI: 1.27-4.66). Our study suggested that the longer duration of FA supplementation before pregnancy might increase the risk of GDM, but decrease the risk of SGA birth. Longer duration of FA supplementation during pregnancy had beneficial effects on birth outcomes in women with GDM. Further studies should consider a larger sample size to confirm these findings.

Effect of feeding patterns on growth and nutritional status of children aged 0-24 months: A Chinese cohort study.

OBJECTIVE: This study was aimed to examine the effect of feeding patterns on growth and nutritional status of children aged 0~24 months. METHODS: We conducted a cohort study with an initial sample of 927 children. Considering the follow-up losses, 903, 897, 895, 897, 883, 827 and 750 children were followed up at 1, 3, 6, 8, 12, 18 and 24 months, respectively. Children were grouped according to exclusive breastfeeding (EBF) duration in the first 6 months: (1) never EBF; (2) EBF ≤ 3 months: EBF ≤ 3 months and stopped BF after 3 months or EBF ≤ 3 months and BF = 6 months or EBF ≤ 3 months and BF after 3 months, had formula and/or solids; (3) EBF for 3 ~ 6 months: BF < 3 months and EBF for 3 ~ 6 months or EBF for 3 ~ 6 months and BF < 3 months, had formula and/or solids; (4) EBF = 6 months. We used Z-scores to evaluate the growth and nutritional status of children, used the generalized estimation equation to compare the difference between feeding patterns. RESULTS: The generalized estimation equation results showed that Weight-for-age Z-score (WAZ), Length-for-age Z-score (LAZ), and Weight-for-length Z-score (WLZ) in different feeding patterns had statistical significance. The WAZ in EBF for 6 months group was higher in the first 8 months, in never EBF group was higher after 12 months old; the LAZ in EBF for 6 month group was lower than other groups; the WLZ in EBF for 6 months group was higher than EBF for 3 ~ 6 months group. The EBF ≤ 3 months group had higher underweight, stunting, and wasting rates. The EBF for 6 months had a higher stunting rate; the never EBF and EBF for 6 months groups had higher overweight and obesity rates. CONCLUSIONS: In conclusion, different feeding patterns affect growth and nutritional status in children, so proper guidelines should be implemented to improve nutritional status and promote the growth of children.

A prospective study of maternal postnatal depressive symptoms with infant-feeding practices in a Chinese birth cohort.

BACKGROUND: The first few weeks after childbirth are critical, as women may encounter lactation problems and postpartum depression during this period. However, it is still unclear whether early breastfeeding behaviours are related to the symptoms of postnatal depression (PND) in Chinese populations. Therefore, the current study aimed to investigate the association between symptoms of PND and infant feeding practices based on a large-scale Chinese cohort. METHODS: A prospective study of the community-based cohort was conducted from January 2015 to December 2016. Infant feeding outcomes, including exclusive/partial breastfeeding and formula feeding, were assessed according to the WHO guidelines. Symptoms of PND were assessed by the Edinburgh Postnatal Depression Scale at 4 weeks postpartum. Multivariate generalized estimating equation models were applied to investigate the associations between depressive symptoms and infant feeding behaviours. RESULTS: A total of 956 mother-infant pairs were included. Fifty-six mothers presented screen-positive symptoms of PND with a cut-off ≥10. The percentage of early breastfeeding initiation was 75.8%, while the average duration of exclusive breastfeeding was 3.90 ± 2.33 months. Postnatal depressive symptoms were associated with a shorter breastfeeding duration (8.02 vs. 6.32 months, P < 0.05) and earlier formula introduction (4.98 vs. 3.60 months, P < 0.05). After adjustments were made for covariates, postnatal depressive symptoms were associated with an increased risk of the discontinuation of exclusive and partial breastfeeding (ß = - 0.049, P = 0.047 and ß = - 0.082, P = 0.006, respectively). Compared to mothers without symptoms of PND, mothers with depressive symptoms were more likely to supplement formula for their infants in the first year of life (ß =0.074, P = 0.016). These associations were still significant in the sensitivity analyses, using an EPDS cut-off of ≥13. CONCLUSIONS: Our findings indicate that depressive symptoms at 4 weeks postpartum are associated with the cessation of exclusive and partial breastfeeding duration and the introduction of formula in the 12 months of delivery. Early psychosocial assessment and social support should be offered to mothers in the early postpartum period to indirectly prevent adverse breastfeeding outcomes.

Effects of Maternal Prenatal Multi-Micronutrient Supplementation on Growth and Development until 3 Years of Age.

At present, there is insufficient evidence on whether prenatal multi-micronutrient (MM) supplementation can be an antenatal nutritional intervention or not. This study aimed to explore the sustained effect of prenatal MM supplementation on early childhood health. A total of 939 mother-offspring pairs were followed up in the study between 2015 to 2018 in Changsha, China. Information was mainly collected through household surveys at the ages of 1, 3, 6, 8, 12, 18, 24, and 36 months. General linear models and generalized estimating equation models were used to estimate the effects of maternal prenatal MM compared with IFA supplementation on infant growth and development. Offspring of women who used prenatal MM compared with IFA supplements had lower weight-for-age z score (WAZ) (adjusted ß: -0.23, 95% CI: (-0.40, -0.06)) and weight-for-length z score (WLZ) (adjusted ß: -0.20, 95% CI: (-0.37, -0.02)) at 3 months old, but a reduced risk of obesity at birth (aRR: 0.30, 95% CI: 0.11-0.78) and being overweight at 3 months old (aRR: 0.52, 95% CI: 0.32-0.84). Moreover, offspring of women who used prenatal MM compared with IFA supplements had significantly higher scores for communication (adjusted ß: 0.41, 95% CI: 0.61-0.21), gross motor (adjusted ß: 0.68, 95% CI: 0.49-0.88), fine motor (adjusted ß: 1.64, 95% CI: 1.45-1.84), problem solving (adjusted ß: 0.29, 95% CI: 0.10-0.49), and personal-social (adjusted ß: 0.90, 95% CI: 0.70-1.10) skills at 36 months old. Prenatal MM supplementation could result in better infant growth in the first few months of life and improve development scores at the age of 3 years compared with IFA supplementation.

Associations of Pre-Pregnancy BMI, Gestational Weight Gain and Maternal Parity with the Trajectory of Weight in Early Childhood: A Prospective Cohort Study.

BACKGROUND: The association of maternal parity, pre-pregnancy body mass index (BMI) and gestational weight gain (GWG) with childhood weight status has been well studied; however, little is known about these factors with respect to the rate of weight changes in early childhood. METHODS: This study was based on a prospective longitudinal study. The follow-up surveys were conducted at the ages of 1, 3, 6, 8, 12, and 18 months. Child weight was investigated twice at each wave. Data on maternal parity, pre-pregnancy weight and height were collected at baseline. The latent growth curve model was used to examine the effects of interested predictors on the trajectory of weight in early childhood. RESULTS: Finally, 893 eligible mother-child pairs were drawn from the cohort. In adjusted models, multiparas were associated with higher birth weight (ß = 0.103) and slower weight change rate of children (ß = -0.028). Pre-conception BMI (ß = 0.034) and GWG (ß = 0.014) played important roles in the initial status of child weight but did not have effects on the rate of weight changes of the child. CONCLUSIONS: Multiparous pregnancy is associated with both higher mean birth weight and slower weight-growth velocity in early childhood, while pregravid maternal BMI and GWG are only related to the birth weight.

[Factors associated with postpartum weight retention based on the generalized estimation equation in Kaifu Districtin Changsha].

OBJECTIVE: To investigate the current status of the postpartum weight retention (PPWR) in Kaifu District of Changsha, and explore the influential factors with PPWR based on the generalized estimating equation model.
 Methods: A cluster sampling method was applied to select women who gave birth at the health service centers of 3 street communities in Kaifu District of Changsha during 2015. According to the inclusion and exclusion criteria, 783 cases were finally included in the study. Data on PPWR were collected prospectively by using the self-made questionnaire at 1, 3, 6 and 8 months after childbirth. Analysis were performed to investigate the associations between PPWR and its potential factors with generalized estimation equation model.
 Results: The mean PPWR of women was gradually decreased with the increase of postpartum time, and 34.6% of them have returned to the pre-pregnancy weight in the 8 months postpartum. Our findings revealed that gestation weight gain (GWG), pre-pregnancy body mass index, feeding patterns, and delivery mode were significantly associated with maternal PPWR (P<0.05). In contrast, maternal age, educational level, per capita income of family, parity and postpartum depression were not contributed to PPWR (P>0.05).
 Conclusion: GWG is one of the most important predictors for PPWR. The key to reducing PPWR is to control GWG systematically. Early targeted interventions and health education should be taken to prevent women from excessive PPWR at the first-year postpartum, in particular to the women who underwent cesarean deliveries and breastfed their infants. It is conducive to reduce the risks of overweight or obesity caused by PPWR.

Modifiable Individual Factors Associated with Breastfeeding: A Cohort Study in China.

Breast milk is an ideal first food for infants in the initial months of life. This study aimed to identify modifiable individual factors in breastfeeding during the first six months of life in Hunan. This birth cohort study was conducted in three communities in Changsha, Hunan province. Data were collected through maternal health manuals and self-administered questionnaires during the follow-up period. To find risk factors and calculate odds ratios, generalized estimating equation models were applied. The final study included 951 mother-infant pairs. The prevalence of exclusive breastfeeding and any breastfeeding in this study was below the World Health Organization's breastfeeding goals. Infant age, passive smoking after delivery, minor postnatal depression, and feeding-bottles were shown to act negatively on both exclusive breastfeeding and any breastfeeding. In addition, cesarean delivery and delayed breastfeeding initiation had adverse effects on exclusive breastfeeding. Multiparas were less likely to continue any breastfeeding during the first few months. This study highlights the importance of screening probable maternal depression during primary care service and reducing secondhand smoke and feeding-bottle use. The results also suggest that healthcare professionals should provide more assistance and education to multiparas and mothers with cesarean delivery or delayed breastfeeding initiation.

Differences between WHO Growth Standards and China Growth Standards in Assessing the Nutritional Status of Children Aged 0-36 Months Old.

Background: At present, whether to use the World Health Organization's (WHO) growth standards or native growth standards to assess the nutritional status in a given population is unclear. This study aimed to compare the differences between the WHO's growth standards and China's growth standards in assessing the nutritional status of children aged 0~36 months. Methods: We used z-scores to evaluate the nutritional status of children. The weight-for-age z-scores (WAZs), length/height-for-age z-scores (LAZ/HAZs), and weight-for-length/height z-scores (WLZ/WHZs) were calculated using the WHO's growth standards and China's growth standards. MeNemar's test was used to compare the nutritional status of children. Results: The results in this study showed that there were differences between the WHO's standards and China's standards in assessing children's nutritional status except for stunting and obesity. The prevalence of underweight assessed using China's standards was higher than when using the WHO's standards (except when 3 and 36 months old). The prevalence of wasting was significantly higher when assessed using China's standards than when using the WHO's standards from 12 to 36 months. The prevalence of overweight was higher when assessed using the WHO's standards from 3 to 8 months. Conclusions: Both the WHO's and China's growth standards are useful measures in assessing children's nutritional status but with key significant differences. Therefore, caution should be taken in selecting appropriate measures in a given population.

An Intrinsically Disordered Peptide-Peptide Stapler for Highly Efficient Protein Ligation Both in Vivo and in Vitro.

Herein, we report an intrinsically disordered protein SpyStapler that can catalyze the isopeptide bond formation between two peptide tags, that is, SpyTag and BDTag, both in vitro and in vivo. SpyStapler and BDTag are developed by splitting SpyCatcher-the cognate protein partner of SpyTag-at the more solvent exposed second loop region. Regardless of their locations in protein constructs, SpyStapler enables efficient covalent coupling of SpyTag and BDTag under a variety of mild conditions in vitro (yield ∼80%). Co-expression of SpyStapler with telechelic dihydrofolate reductase (DHFR) bearing a SpyTag at N-terminus and a BDTag at C-terminus leads to direct cellular synthesis of a circular DHFR. Mechanistic studies involving circular dichroism and nuclear magnetic resonance spectrometry reveal that SpyStapler alone is disordered in solution and forms a stable folded structure ( Tm ∼ 55 °C) in the presence of both SpyTag and BDTag upon isopeptide bonding. No ordered structure can be formed in the absence of either tag. The catalytically inactive SpyStapler-EQ mutant cannot form a stable physical complex with SpyTag and BDTag, but it can fold into ordered structure in the presence of the ligated product (SpyTag-BDTag). It suggests that the isopeptide bond is important in stabilizing the complex. Given its efficiency, resilience, and robustness, SpyStapler provides new opportunities for bioconjugation and creation of complex protein architectures.

SpyCatcher-NTEV: A Circularly Permuted, Disordered SpyCatcher Variant for Less Trace Ligation.

The SpyTag/SpyCatcher reaction has emerged as a powerful way for bioconjugation, but it leaves a folded complex in the product after the formation of the isopeptide bond. To vary the location of the reactive residue and reduce the size of the complex and its potential immunogenicity, we engineer two circularly permuted SpyCatcher variants, SpyCatcher-N and SpyCatcher-NTEV, the latter of which possesses a TEV-recognition site for removal of the fragment containing the catalytic site. Surprisingly, both variants are found to be disordered in solution, yet still retain the ability to form an ordered complex upon reaction with SpyTag with second-order rate constants of ∼10 M-1 s-1. Cellular expression of a telechelic protein bearing SpyCatcher-NTEV at the N-terminus and SpyTag at the C-terminus gives both cyclized and chain-extended products. Notably, the monomers exist almost exclusively in the cyclic form owing to its high reactivity in vivo. The fragment containing the catalytic site of SpyCatcher-NTEV can then be removed by TEV digestion, giving a circular protein with minimal trace from the ligation reaction. The plasticity of SpyTag/SpyCatcher reactive pair has promised an ever-expanding toolbox of genetically encoded peptide-protein reaction with versatile features.

Tuning SpyTag-SpyCatcher mutant pairs toward orthogonal reactivity encryption.

Genetically encoded covalent peptide tagging technology, such as the SpyTag-SpyCatcher reaction, has emerged as a unique way to do chemistry with proteins. Herein, we report the reactivity engineering of SpyTag-SpyCatcher mutant pairs and show that distinct reactivity can be encrypted for the same reaction based on protein sequences of high similarity. Valuable features, including high selectivity, inverse temperature dependence and (nearly) orthogonal reactivity, could be achieved based on as few as three mutations. This demonstrates the robustness of the SpyTag-SpyCatcher reaction and the plasticity of its sequence specificity, pointing to a family of engineered protein chemistry tools.

Topology Engineering of Proteins in Vivo Using Genetically Encoded, Mechanically Interlocking SpyX Modules for Enhanced Stability.

Recombinant proteins are traditionally limited to linear configuration. Herein, we report in vivo protein topology engineering using highly efficient, mechanically interlocking SpyX modules named AXB and BXA. SpyX modules are protein domains composed of p53dim (X), SpyTag (A), and SpyCatcher (B). The p53dim guides the intertwining of the two nascent protein chains followed by autocatalytic isopeptide bond formation between SpyTag and SpyCatcher to fulfill the interlocking, leading to a variety of backbone topologies. Direct expression of AXB or BXA produces protein catenanes with distinct ring sizes. Recombinant proteins containing SpyX modules are obtained either as mechanically interlocked obligate dimers if the protein of interest is fused to the N- or C-terminus of SpyX modules, or as star proteins if the protein is fused to both N- and C-termini. As examples, cellular syntheses of dimers of (GB1)2 (where GB1 stands for immunoglobulin-binding domain B1 of streptococcal protein G) and of four-arm elastin-like star proteins were demonstrated. Comparison of the catenation efficiencies in different constructs reveals that BXA is generally much more effective than AXB, which is rationalized by the arrangement of three domains in space. Mechanical interlocking induces considerable stability enhancement. Both AXB and BXA have a melting point ∼20 °C higher than the linear controls and the BXA catenane has a melting point ~2 °C higher than the cyclic control BX'A. Notably, four-arm elastin-like star proteins demonstrate remarkable tolerance against trypsin digestion. The SpyX modules provide a convenient and versatile approach to construct unconventional protein topologies via the "assembly-reaction" synergy, which opens a new horizon in protein science for stability enhancement and function reinforcement via topology engineering.

Phenylenediamine-based FeN(x)/C catalyst with high activity for oxygen reduction in acid medium and its active-site probing.

High-temperature pyrolyzed FeN(x)/C catalyst is one of the most promising nonprecious metal electrocatalysts for oxygen reduction reaction (ORR). However, it suffers from two challenging problems: insufficient ORR activity and unclear active site structure. Herein, we report a FeN(x)/C catalyst derived from poly-m-phenylenediamine (PmPDA-FeN(x)/C) that possesses high ORR activity (11.5 A g(-1) at 0.80 V vs RHE) and low H2O2 yield (<1%) in acid medium. The PmPDA-FeN(x)/C also exhibits high catalytic activity for both reduction and oxidation of H2O2. We further find that the ORR activity of PmPDA-FeN(x)/C is not sensitive to CO and NO(x) but can be suppressed significantly by halide ions (e.g., Cl(-), F(-), and Br(-)) and low valence state sulfur-containing species (e.g., SCN(-), SO2, and H2S). This result reveals that the active sites of the FeN(x)/C catalyst contains Fe element (mainly as Fe(III) at high potentials) in acid medium.