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Tomato is one of the most important vegetable crops in the world and is a model plant used to study the ripening of climacteric fleshy fruit. During the ripening process of tomato fruit, flavor and aroma metabolites, color, texture and plant hormones undergo significant changes. However, low temperatures delayed the ripening process of tomato fruit, inhibiting flavor compounds and ethylene production. Metabolomics and transcriptomics analyses of tomato fruit stored under low temperature (LT, 5°C) and room temperature (RT, 25°C) were carried out to investigate the effects of storage temperature on the physiological changes in tomato fruit after harvest. The results of transcriptomics changes revealed that the differentially expressed genes (DEGs) involved in tomato fruit ripening, including several kinds of transcription factors (TFs) (TCP, WRKY, MYB and bZIP), enzymes involved in cell wall metabolism [beta-galactosidase (β-GAL), pectinesterase (PE) and pectate lyase (PL), cellulose and cellulose synthase (CESA)], enzymes associated with fruit flavor and aroma [acetyltransferase (AT), malic enzyme (ME), lipoxygenase(LOX), aldehyde dehydrogenase (ALDH), alcohol dehydrogenase (ADH) and hexokinase (HK)], genes associated with heat stress protein 70 and genes involved in the production of plant hormones such as Ethylene responsive factor 1 (ERF1), Auxin/indoleacetic acids protein (AUX/IAA), gibberellin regulated protein. Based on the above results, we constructed a regulatory network model of the effects of different temperatures during the fruit ripening process. According to the analysis of the metabolomics results, it was found that the contents of many metabolites in tomato fruit were greatly affected by storage temperature, including, organic acids (L-tartaric acid, a-hydroxyisobutyric acid and 4-acetamidobutyric acid), sugars (melezitose, beta-D-lactose, D-sedoheptulose 7-phosphate, 2-deoxyribose 1-phosphate and raffinose) and phenols (coniferin, curcumin and feruloylputrescine). This study revealed the effects of storage temperature on postharvest tomato fruit and provided a basis for further understanding of the molecular biology and biochemistry of fruit ripening.

Ferritin is a cage-like protein with a modifiable exterior surface. In this study, transglutaminase was applied to catalyze the glycosylation of oligochitosan onto the apo-red bean seed ferritin (apoRBF) to fabricate an oligochitosan-modified apoRBF nanoparticle (OFN). Results indicated that the oligochitosan glycosylation retained the shell-like structure of ferritin and improved its thermal stability. The reversible assembly of OFN regulated by pH and urea transition was successfully retained. By using this assembly routine, rutin can be encapsulated within the OFN either by pH 2.0/7.0 transition or urea (8.0 M/0 M) transition, and the size distribution of rutin-loaded OFN was mainly about 12 nm. Moreover, the thermal stability of the rutin in the OFN was significantly improved as compared with that in apoRBF. The present study will be beneficial for extension of chitosan and Transglutaminase applications in protein modification, and will improve ferritin functionalization as a nanocarrier for food bioactive molecules.

The commercial Hβ (25, 50), HY (11) and HZSM-5(50) were dealuminated by acid leaching and subsequent calcination to improve their hydrophobic nature for the removal of bisphenol A (BPA). The structure and properties of the raw zeolites and the modified ones (labelled as T-Hβ (25, 50), T-HY (11), T-HZSM-5(50)) have been investigated comparatively by XRD, BET, SEM, XRF and contact angle test (CA). The results indicated that HY (11) and T-HY (11) had poor adsorption capacity for hydrophobic BPA because of destroyed crystalline phase of T-HY (11) and hydrophilic nature of HY (11). HZSM-5(50) and T-HZSM-5(50) also had poor adsorption ability for BPA molecules because larger BPA molecules cannot enter smaller pores of HZSM-5(50) and T-HZSM-5(50). However, the T-Hβ (25, 50) zeolites exhibited significantly higher adsorption capacity for BPA because their larger pore size remained than molecule size of BPA and larger water contact angles and molar ratios of SiO2/Al2O3 of T-Hβ (25, 50) than Hβ (25, 50), respectively. BPA removal mechanism study showed that hydrophobic interaction force between BPA and T-Hβ (25, 50) should be a main driving force. The adsorption process conformed to pseudo-second order model and the three-parameter Redlich-Peterson model. The adsorption rate of BPA over T-Hβ (50) (0.01050 ​g ​mg−1 ​min−1) was 2.29 times faster than that over Hβ (50) (0.004581 ​g ​mg−1 min−1), and the maximum adsorption capacity of BPA on T-Hβ (50) (117.62 ​mg ​g−1) was 3.5 times than that on Hβ (50) (33.78 ​mg ​g−1). The acid treatment-calcination method is feasible and appropriate for modification of Hβ in order to remove hydrophobic organic pollutants.

Ferritin is characterized by a shell-like structure and a reversible self-assembly property. In this study, atmospheric cold plasma (ACP) was applied to red bean seed ferritin (RBF) to prepare an ACP-treated RBF (ACPF). Results indicated that the ACP treatment retained the shell-like structure of ferritin but reduced the α-helix/β-sheet contents and thermal stability. Iron oxidative deposition and release activities were also markedly changed. The ACPF could be disassembled at pH 4.0 and then assembled into an intact ferritin cage when pH was increased to 7.0, which was a more benign transition condition than that of the traditional method (pH 2.0/7.0 transition). By using this assembly routine, curcumin was successfully encapsulated within the ACPF with a size distribution of 12 nm. Moreover, the encapsulation ratio of curcumin in the ACPF reached 12.7% (w/w). This finding can be used to expand the application of ACP and improve the functionalization of the ferritin.

The inner surface and outer surface of ferritin cage provide interfaces for the encapsulation and delivery of food nutrients. Traditional methods to fabricate ferritin-nutrients shell-core nanoparticle usually apply acid/alkaline pH transition, which may cause the activity loss of the food nutrients or the formation of insoluble aggregates. In attempt to tackle these limitations, a simple one-step method was utilized to prepare the red bean seed ferritin (RBF)-epigallocatechin (EGC)-chitosan nanoparticle (REC) by thermal treatment at 55 °C. Results indicated that the apoRBF was partially uncoiled with a decrease of 5.3% of α-helix content induced by 55 °C treatment, and the EGC molecules could spontaneously permeate into the inner cavity of the ferritin with an encapsulation ratio of 11.8% (w/w). Meanwhile, the thermal treatment facilitated the chitosan attaching onto the outer surface of the ferritin by electrostatic interactions with a binding constant of 4.7 × 105 M−1. Transmission electron microscope and dynamic light scattering results indicated that the REC was mono-dispersedly distributed, with a diameter of 12 nm and a hydrodynamic radius (RH) of 7.3 nm. In addition, the chitosan decorating onto the apoRBF improved the EGC stability by weakening the degradation of apoRBF against digestive enzymes in simulated gastrointestinal tract. This work is a novel attempt to fabricate shell-core nanoparticle in the encapsulation and delivery of functional molecules based on the ferritin cage in a benign condition without extreme pH changes.

Ferritin is an iron-containing protein and functions in the maintenance of iron balance in organisms. Currently the interaction among ferritin, ion iron, and food bioactive compounds is still unclear. In this study, the mechanism underlying the interaction of ferritin, ion iron, and chlorogenic acid was investigated, as well as the effect of chlorogenic acid on the physicochemical properties of ferritin. The results showed that chlorogenic acid could interact with Fe(III) to form chlorogenic acid-Fe(III) complexes, which then bonded with ferritin via hydrogen bonds in the ferritin-chlorogenic acid-Fe(III) complexes. The chlorogenic acid showed a high efficiency in Fe(II) chelation and hydroxyl radical (•OH) capture, and could promote iron oxidation and iron release induced by ferritin. Chlorogenic acid could also effectively reduce the polymerization extent of ferritin induced by Fe(III) and Fe(II). This study elucidates the interactions of multiple components in foodstuffs by using a protein-metal-polyphenol model.

The antibacterial peptide mytichitin-CB has been highly expressed in Pichia pastoris. In this study, we aim to investigate its potential for application in pork preservation. P. pastoris-derived mytichitin-CB exhibited broad and potent antibacterial activity against four common foodborne bacterial pathogens and two food spoilage bacteria of Pseudomonas spp. with low minimal inhibition concentrations of 0.23–1.24 μg/mL. Mytichitin-CB effectively suppressed the growth of the microflora and significantly reduced the increases in pH, drip loss, total volatile basic nitrogen (TVB-N), and thiobarbituric acid reactive substances (TBARS) of fresh pork during storage at 4 °C. Consequently, the fresh pork maintained its desirable sensory properties. Mytichitin-CB could also effectively inhibit the growth of Staphylococcus aureus, Escherichia coli O157, and Pseudomonas fluorescens in a pork spoilage model. Combining mytichitin-CB with chitosan and nisin at the optimal proportion further enhanced the antibacterial activity and effects of food preservation on fresh pork, as evidenced by improved sensory properties, lowered drip loss and TVB-N production, and reduced change in pH during storage. However, combining these three agents failed to further increase antioxidant activity against lipid oxidation. Overall, the combination of 4 mg/L of mytichitin-CB with 10 g/L of chitosan incorporated with 300 mg/L of nisin exhibited the best performance in fresh pork preservation. The combined findings suggest that treatment with mytichitin-CB alone or in combination with chitosan and nisin has considerable potential in the preservation of fresh meat products to extend the shelf life and assure the quality and safety of meat.

It has been demonstrated that Agaricus bisporus (J.E. Kange) Imbach fruit body exerts enhanced postharvest quality retention when treated with 100 μmol L −1 exogenous methyl jasmonate (MeJA) vapor. In this study, fruit bodies of A. bisporus were treated with 100 μmol L −1 MeJA vapor or the combination of 100 μmol L −1 MeJA and 20 μmol L −1 N ω -hydroxy-nor- l -arginine (nor-NOHA, an inhibitor of arginase), respectively, before they were stored for 21 d at 4 °C. Our data showed that treatment with MeJA alone indeed induced the increased transcription and activity of arginase whereas this effect was largely inhibited by pretreatment with nor-NOHA. In correspondence to this observation, nor-NOHA suppressed the ability of MeJA to decrease open caps and to down-regulate malondialdehyde (MDA) production and polyphenol oxidase (PPO) and lipoxygenase (LOX) activities. Biochemical analysis further demonstrated that nor-NOHA counteracted the MeJA in stimulating antioxidant enzyme activities of catalase (CAT) and superoxide dismutase (SOD) and accumulating total phenolics and flavonoids. In addition, the effect of MeJA in slowing the decline rate of soluble protein and total sugar contents was also partially impaired by nor-NOHA. Taken together, our findings firmly showed that arginase acts as an important regulatory factor in maintaining the MeJA-induced mushroom quality retention during postharvest storage.

This study investigated changes in endogenous polyamine (PA) content, PA-related amino acid content, and the expression of PA-related genes in different tissues (cap, gill, and stipe) of the edible mushroom (Agaricus bisporus J.E. Lange Imbach) during postharvest storage. The results showed that the putrescine (Put) content increased substantially and continuously in all tissues, and was highest in stipe during storage. Strong positive correlations were observed between Put content and the extent of cap opening. Minor changes in spermidine (Spd) and spermine (Spm) contents were observed during storage, both of which were highest in gills during spore production. PA-related amino acid content and PA-related gene expression were also developmentally and tissue-specifically regulated. The expression levels of AbASS, AbASL, AbARG, and AbOAT increased in gills and reached the highest level when the pileus started cap opening; however, at the same time, in the stipe these expression levels decreased rapidly to the lowest level. The expression levelsof AbODC and AbSAMDC increased in gills with storage duration, which possibly contributed to the highest Spd level. Furthermore, proline and glutamate contents presented an opposite changing trend during storage, indicating that they are likely generated in a coordinated way in different tissues. In addition, Put biosynthetic pathways are likely differently regulated in gill and stipe: Put production in gills mainly happened via ornithine decarboxylase, while Put in stipes may be synthesized via an alternative pathway. These results indicate that PA biosynthesis and its distribution correlate positively with the continuing development of A. bisporus postharvest.

Peste des petits ruminants (PPR) is a highly contagious and fatal disease of small ruminants, particularly sheep and goats. This disease leads to high morbidity and mortality of small ruminants, thus resulting in devastating economic loss to the livestock industry globally. The severe disease impact has prompted the Food and Agriculture Organization of the United Nations (FAO) and the World Organization for Animal Health (OIE) to develop a global strategy for the control and eradication of PPR by 2030. Over the past decades, the control of PPR is mainly achieved through vaccinating the animals with live-attenuated vaccines, e.g., rinderpest vaccines. As a closely related disease to PPR of large ruminants, rinderpest was eradicated in 2011 and its vaccines subsequently got banned in order to keep rinderpest-free zones. Consequently, it is desirable to develop homologous PPR vaccines to control the disease. The present review summarizes the objectives of PPR control and eradication by focusing on the homologous PPR vaccines.

Influenza A virus (IAV) is characterized by eight single-stranded, negative sense RNA segments, which allows for gene reassortment among different IAV subtypes when they co-infect a single host cell simultaneously. Genetic reassortment is an important way to favor the evolution of influenza virus. Novel reassortant virus may pose a pandemic among humans. In history, three human pandemic influenza viruses were caused by genetic reassortment between avian, human and swine influenza viruses. Since 2009, pandemic (H1N1) 2009 (pdm/09 H1N1) influenza virus composed of two swine influenza virus genes highlighted the genetic reassortment again. Due to wide host species and high transmission of the pdm/09 H1N1 influenza virus, many different avian, human or swine influenza virus subtypes may reassert with it to generate novel reassortant viruses, which may result in a next pandemic among humans. So, it is necessary to understand the potential threat of current reassortant viruses between the pdm/09 H1N1 and other influenza viruses to public health. This study summarized the status of the reassortant viruses between the pdm/09 H1N1 and other influenza viruses of different species origins in natural and experimental conditions. The aim of this summarization is to facilitate us to further understand the potential threats of novel reassortant influenza viruses to public health and to make effective prevention and control strategies for these pathogens.

Background 1-Aminocyclopropane-1-carboxylate oxidase (ACO) is a key enzyme that catalyses the final step in the biosynthesis of the plant hormone ethylene. Recently, the first ACO homologue gene was isolated in Agaricus bisporus , whereas information concerning the nature of the ethylene-forming activity of this mushroom ACO is currently lacking. Methods Recombinant ACO from A . bisporus (Ab-ACO) was purified and characterised for the first time. Molecular modelling combined with site-directed mutagenesis and kinetic and spectral analysis were used to investigate the property of Ab-ACO. Results Ab-ACO has eight amino acid residues that are conserved in the Fe (II) ascorbate family of dioxygenases, including four catalytic residues in the active site, but Ab-ACO lacks a key residue, S289. In comparison to plant ACOs, Ab-ACO requires ACC and Fe (II) but does not require ascorbate. In addition, Ab-ACO had relatively low activity and was completely dependent on bicarbonate, which could be ascribed to the replacement of S289 by G289. Moreover, the ferrous ion could induce a change in the tertiary, but not the secondary, structure of Ab-ACO. Conclusions These results provide crucial experimental support for the ability of Ab-ACO to catalyse ethylene formation in a similar manner to that of plant ACOs, but there are differences between the biochemical and catalytic characteristics of Ab-ACO and plant ACOs. General significance This work enhances the understanding of the ethylene biosynthesis pathways in fungi and could promote profound physiological research of the role of ethylene in the regulation of mushroom growth and development.

Treatment of tomato ( Solanum lycopersicum L. cv. Messina) fruit with hot air (HA) at 38 °C enhanced the transcript levels of LeARG1 and LeARG2 , the two genes encoding arginase, and arginase activity. The strongest induction of LeARG1 and LeARG2 transcripts was observed after fruit treated with 38 °C HA for 12 h, which also effectively alleviated chilling injury (CI) of tomato fruit, manifested as decreased CI index, electrolyte leakage and malondialdehyde content during cold storage. To investigate the potential role of arginase in HA-induced chilling tolerance, fruit were treated with HA, or arginase inhibitor Nω-hydroxy-nor- l -arginine (nor-NOHA) combined with HA and then stored at 2 °C for up to 28 d. The results showed that HA-induced arginase activity was strongly inhibited by pretreatment with nor-NOHA and the reduction of CI by HA was nearly abolished by the arginase inhibitor. In addition, HA treatment increased activities of superoxide dismutase, catalase and ascorbate peroxidase, inhibited peroxidase activities, and promoted the accumulation of arginine, proline and putrescine. These effects were partially counteracted by nor-NOHA except that arginine and putrescine accumulation was unaffected. Our results indicate that arginase induction may be partly involved in HA-induced chilling tolerance in tomato fruit, possibly by a mechanism involving activation of antioxidant enzymes and an increase in proline levels.

Freshly harvested tomato fruit were pretreated with 0.2 mM arginine at −35 kPa for 0.5 min and then stored at 2 °C for 28 d to investigate the effect of exogenous arginine treatment on endogenous arginine catabolism in relation to chilling injury (CI). Arginine treatment reduced the CI index of fruit and enhanced accumulation of polyamines, especially putrescine, and proline, which resulted from the increased activities of the catabolic enzymes arginase, arginine decarboxylase, ornithine decarboxylase and ornithine δ-aminotransferase at most sampling times. Nitric oxide synthase activity was also increased by arginine treatment, which at least partly contributed to the increased nitric oxide concentration. These results revealed that the reduction in CI by exogenous arginine may be due to the accumulation of putrescine, proline and nitric oxide induced by activating the different pathways of endogenous arginine catabolism.

The influence of methyl jasmonate (MeJA) on levels of gene transcripts, enzyme activities and metabolites related to arginine catabolism and chilling injury (CI) was studied in cherry tomato (Solanum lycopersicum L. cv. Messina) fruit stored at 2 °C for 21 days. The CI index of fruit pretreated with 0.05 mM MeJA vapor for 12 h at 20 °C was reduced compared with that of untreated fruit. The reduction was associated with up-regulated arginine catabolism. The mRNA levels and activities of arginase, arginine decarboxylase (ADC) and ornithine aminotransferase (OAT) in treated fruit were higher than in control fruit, while those of ornithine decarboxylase (ODC) increased transiently in response to MeJA treatment during the early days of cold storage. Free putrescine (Put) and proline accumulated in MeJA-treated fruit, while levels of other arginine-related amino acids were affected by MeJA. Spermidine (Spd) and spermine (Spm) contents remained unchanged in response to MeJA treatment over most of the storage time. The results indicate that MeJA becomes involved in coordinated catabolism of arginine, and helps to improve chilling tolerance in cherry tomato fruit.