Unraveling the metabolic potential of biocontrol fungi through omics data: a key to enhancing large-scaleapplication strategies.

Biological control of pests and pathogens has attracted much attention due to its green, safe and effective characteristics. However, it faces the dilemma of insignificant effects in large-scale applications. Therefore, an in-depth exploration of the metabolic potential of biocontrol fungi based on big omics data is crucial for a comprehensive and systematic understanding of the specific modes of action operated by various biocontrol fungi. This article analyzes the preferences for extracellular carbon and nitrogen source degradation, secondary metabolites (nonribosomal peptides, polyketide synthases) and their product characteristics and the conversion relationship between extracellular primary metabolism and intracellular secondary metabolism for eight different filamentous fungi with characteristics appropriate for the biological control of bacterial pathogens and phytopathogenic nematodes. Further clarification is provided that Paecilomyces lilacinus, encoding a large number of hydrolase enzymes capable of degrading pathogen protection barrier, can be directly applied in the field as a predatory biocontrol fungus, whereas Trichoderma, as an antibiosis-active biocontrol control fungus, can form dominant strains on preferred substrates and produce a large number of secondary metabolites to achieve antibacterial effects. By clarifying the levels of biological control achievable by different biocontrol fungi, we provide a theoretical foundation for their application to cropping habitats.

Dietary ferulic acid improves growth performance of broilers via enhanced intestinal antioxidant capacity and barrier function.

Objective: In this study, the effects of dietary ferulic acid (FA) on the growth traits, antioxidant capacity, and intestinal barrier function of broilers were investigated. Methods: In total, 192 male Arbor Acres broilers were randomly allocated to one of three dietary groups (8 replicates of 8 birds each): control (CON) group (basal diet), FA100 group (basal diet + 100 mg/kg FA), or FA200 group (basal diet + 200 mg/kg FA). The duration of the feeding trial was 42 days. Results: higher average daily gain (ADG) and lower feed to gain (F/G) ratio during day 0 to day 21 were found in the FA100 and FA200 groups, while higher ADG and lower F/G during day 21 to day 42 were only found in FA200 group, compared to the CON group (p < 0.05). Serum levels of MDA and DAO on day 21 were lower in the FA100 and FA200 groups and those on day 42 were lower in the FA200 group, while GSH-Px level in the FA100 and FA200 groups on day 21 and that in the FA200 group on day 42 were increased (p < 0.05). On day 21, jejunal GSS expression was upregulated in the FA200 group (p < 0.05), while jejunal and ileal expression of NRF2 and Occludin as well as ileal expression of GPX1 and ZO1 were increased in the FA100 and FA200 groups compared to the CON group (p < 0.05). On day 42, mRNA expression of GSS, NRF2, SOD1, and GPX1 in the jejunum and ileum as well as Claudin2 in the jejunum and Occludin in the ileum were increased in the FA200 group (p < 0.05). Conclusion: Dietary FA addition could improve the growth performance, antioxidant capacity, and gut integrity of broilers. The current findings provided evidences that the adoption of FA can be as nutrition intervention measure to achieve high-efficient broiler production for poultry farmers.

Response of Neuropeptides to Hunger Signals in Teleost.

INTRODUCTION: The perception of hunger is a complex physiological process that requires precise coordination between the central and peripheral tissues. METHODS: In this study, tilapia fasted for 24 h was chosen to establish a hunger model to study the mechanism of homeostasis recovery under the joint regulation of the central nervous system (CNS) and peripheral tissues. RESULTS: The gastric and intestinal contents of tilapia were predominantly depleted after a fasting period of 9 h and 24 h, respectively. The serum glucose level significantly decreased at the 9-h and 24-h fasting, respectively, and the glucokinase-dependent glucosensing mechanism in the liver was identified as well as the significant activation of phospho-AMPK. However, fasting for 24 h did not activate glucosensing mechanisms and AMPK signaling pathways in the hypothalamus. On the other hand, significant reductions were observed in the mRNA levels of the lipid synthesis-related genes fas and accα, and the serum triglyceride levels as well. The mRNA levels of npy, agrp, pomc, and cart in the hypothalamus fluctuated during the fasting period without significant differences. With in situ hybridization npy signals upregulated in the ventral zone of posterior periventricular nucleus after 24-h fasting, pomc signals enhanced in the lateral tuberal nucleus. Based on the serum metabolomic analysis, the levels of branched-chain amino acids, butyrate, and short-chain acylcarnitine decreased, while those of medium- and long-chain acylcarnitine increased. CONCLUSION: Fasting for 24 h resulted in changes in npy and pomc signals within the hypothalamus and triggered the glucosensing mechanism in the liver of tilapia. This study is beneficial for elucidating the response of neuropeptides in the CNS to the changes of nutritional factors when hungry.

Effects of Dried Blueberry Pomace and Pineapple Pomace on Growth Performance and Meat Quality of Broiler Chickens.

The purpose of this study was to investigate the effects of dried blueberry pomace (BP) and pineapple pomace (PP) on the growth performance and meat quality of broiler chickens. A total of 240 1-day-old Ross 308 broiler chickens were randomly divided into 3 groups, with 10 replicates per treatment group and 8 birds per replicate (4 males and 4 females). The three groups were the control (CON) group, the 3% BP group, and 3% PP group. The entire trial period lasted 42 days. The results show that the average daily feed intake, average daily gain, and feed-to-gain ratio of the BP group and the PP group were not significantly different from those in the CON group (p > 0.05). Adding BP to the diet significantly reduced the proportion of liver and giblets (p < 0.05). Adding PP to the diet significantly reduced the proportion of liver, while the proportion of gizzard significantly increased (p < 0.05). The pH24h and L* of breast muscles were significantly lower in the PP group than in the CON group (p < 0.05). The water-holding capacity of the leg muscles in the BP group and the PP group was significantly lower than that in the CON group (p < 0.05). The crude protein content of breast muscle and the ether extract content of leg muscle in the BP group were significantly lower than those in the CON group (p < 0.05). In conclusion, the addition of 3% BP and PP to broiler chickens' diets had no adverse effects on growth performance or meat quality.

Scientific Landscape of Oxidative Stress in Stroke: From a Bibliometric Analysis to an in-Depth Review.

Stroke is an acute cerebrovascular disease resulting from either obstruction or rupture of a blood vessel in the brain. Oxidative stress (OS), referred to a status where cellular oxidative capacities overwhelm antioxidative defenses, is involved in the pathophysiology of stroke. The bibliometric analysis and in-depth review aim to depict the research trend of OS in stroke. Relevant scientific publications were acquired from the Web of Science Core Collection database. Scientific landscape of OS in stroke was illustrated by general quantitative trend, impactful journals, and co-authorship of various academic units (i.e., countries/regions, organizations, and authors). Furthermore, theme analysis predicting the hot research issues and frontiers was performed. 15,826 documents regarding OS in stroke were obtained over a time span of more than 20 years from 1992 to 2021. The overall tendency of publication counts was continuously on the rise. Bibliometric analysis indicated China and the United States were predominant in this study field, as reflected by their high publication counts and intensive collaboration with other countries. Current key research areas of OS in stroke may lie in the investigation of neuroinflammation, and interaction among multiple cell death mechanisms including apoptosis, autophagy, and ferroptosis to search for effective treatments. Moreover, another hot topic could be the association between air pollution and stroke, and its underlying mechanisms. As the exploration of OS in stroke is speculated to be a continuous hot spot in the future, this article may be helpful for researchers to conduct future studies with the understanding of influential academic forces and research highlights.

Study on the flocculation mechanism of a bioflocculant from Acinetobacter sp. TH40 combined with graphene oxide for the removal of metal ions from water.

In order to realize the simultaneous removal of nine metal ions from water, in this study, an excellent flocculant suitable for the simultaneous removal of multiple metal ions in water was developed by using the excellent flocculation properties of graphene oxide (GO) combined with biological flocculants. First, this study investigated the concentrations and pollution levels of nine metal pollutants in surface water and groundwater of a typical city in central China. The maximum concentrations of these nine metal ions were Al 0.29, Ni 0.0325, Ba 0.948, Fe 1.12, As 0.05, Cd 0.01, Zn 1.45, Mn 1.24, and Hg 0.16 (in mg/L). Second, the three-dimensional structure diagram of GO was established. Gaussian16W software and the pm6D3 semi-empirical method were used to analysis the structure and the vibration of GO. The B3LYP function and basis set DEF2SVP was used to calculate the single point energy. Third, with varying the flocculation time, it was found that the maximum flocculation efficiency could reach more than 80.00% under the optimal conditions, that is, with a metal ion mixture of 20 mg/L. The optimal dosage of GO was 15 mg/L. The optimal time for bioflocculation efficiency was 2.5 h, and the optimal concentration of bioflocculant was 3 mg/L. The optimal flocculation efficiency was 82.01% under the optimal conditions.

The Holothuria leucospilota genome elucidates sacrificial organ expulsion and bioadhesive trap enriched with amyloid-patterned proteins.

Some tropical sea cucumbers of the family Holothuriidae can efficiently repel or even fatally ensnare predators by sacrificially ejecting a bioadhesive matrix termed the Cuvierian organ (CO), so named by the French zoologist Georges Cuvier who first described it in 1831. Still, the precise mechanisms for how adhesiveness genetically arose in CO and how sea cucumbers perceive and transduce danger signals for CO expulsion during defense have remained unclear. Here, we report the first high-quality, chromosome-level genome assembly of Holothuria leucospilota, an ecologically significant sea cucumber with prototypical CO. The H. leucospilota genome reveals characteristic long-repeat signatures in CO-specific outer-layer proteins, analogous to fibrous proteins of disparate species origins, including spider spidroin and silkworm fibroin. Intriguingly, several CO-specific proteins occur with amyloid-like patterns featuring extensive intramolecular cross-ß structures readily stainable by amyloid indicator dyes. Distinct proteins within the CO connective tissue and outer surface cooperate to give the expelled matrix its apparent tenacity and adhesiveness, respectively. Genomic evidence offers further hints that H. leucospilota directly transduces predator-induced mechanical pressure onto the CO surface through mediation by transient receptor potential channels, which culminates in acetylcholine-triggered CO expulsion in part or in entirety. Evolutionarily, innovative events in two distinct regions of the H. leucospilota genome have apparently spurred CO's differentiation from the respiratory tree to a lethal defensive organ against predators.

Effects of self-care programs on the incidence of diabetes among adults with prediabetes: A systematic review and meta-analysis of randomised controlled trials.

OBJECTIVES: To verify the effects of self-care programs among adults with prediabetes, to identify the preferable structure components and to summarise the core content components of self-care programs. DESIGN: A systematic review and meta-analysis of randomised controlled trials. METHODS: PubMed, Embase, Cochrane, CINAHL, PsycINFO, Wanfang, CNKI, Chinese Biomedical Database and Open Grey were searched for studies published from January 2002 to December, 2021. Meta-analysis was conducted to verify the effects of self-care programs on diabetes incidence. Subgroup analyses based on structure components were performed to contrast the effects. We made a critical analysis to generalise the core elements of content components. The study was reported according to PRISMA statement. RESULTS: Totally, 15 studies were included in systematic review, of which 14 studies were eligible for meta-analysis. The results of meta-analysis showed the incidence of diabetes for prediabetic adults receiving self-care programs was significantly lower than those who received usual care (OR 0.58; 95% CI 0.46 to 0.73). The results of subgroup analyses based on delivery mode, intervention implementer, health education brochures provided, and follow-up duration showed statistically significant reduction in incidence compared with control group (p < .05). However, the differences of these pair-wise comparisons (face-to-face or remote, individual or interdisciplinary team, with or without brochures provided, ≤1 year or >1 year) were not statistically significant (p > .05). Three core content elements were generalised: cognitive education, behaviour guidance and psychological support. CONCLUSIONS: Self-care programs can effectively delay the progression of prediabetes to diabetes. Regardless of the diversified structure components, self-care programs can achieve better effects on the diabetes incidence than usual care, while the optimal structure components still remain unknown. Cognitive education, behaviour guidance and psychological support are core elements for these programs. RELEVANCE TO CLINICAL PRACTICE: More clinical trials with rigorous study design are needed to provide further evidence.

Neurosecretory protein GL in GIFT tilapia (Oreochromis niloticus): cDNA cloning, tissue distribution and effects of feeding on its expression.

Neurosecretory protein GL (NPGL), a novel neuropeptide, has been identified in the hypothalamus of chicks and rodents. NPGL plays a crucial role in monitoring energetic status via the regulation of feeding and metabolism. However, no study on NPGL has been reported in fish thus far. In the present study, the full-length cDNA of NPGL was identified from the hypothalamus of GIFT tilapia (Oreochromis niloticus). The ORF of tilapia NPGL is 471 bp and encodes a precursor peptide with a size of 156 a.a, consisting of a 26 a.a signal peptide and an 82 a.a mature peptide. Tissue distribution profiles of npgl in tilapia were acquired using semiquantitative PCR and in situ hybridization (ISH). The results showed that the highest npgl mRNA is expressed in the telencephalic-preoptic complex, which comprises both the telencephalon and the anterior preoptic area (POA) of male tilapia, and in the ovary of female tilapia. In addition, in male tilapia, the ISH results showed that the cells containing npgl mRNA were distributed exclusively in the anterior periventricular pretectal nucleus (Ppa) of the POA. FISH results demonstrated that npgl mRNA is also expressed in the lateral tuberal nucleus of the hypothalamus (NLT). Real-time PCR showed that npgl mRNA significantly increased in the telencephalic-preoptic complex of male tilapia that were fasted for 24 h and then fed a full diet for 20 min compared with the unfed group. Results of the FISH study showed that parvocellular cells containing npgl mRNA in the Ppa of fed fish were apparently more abundant than those of the unfed group. Few npgl positive signals also appeared in the NLT after full feeding, where pomc mRNA is highly expressed. These results indicate that NPGL may be a short-term satiety factor in fish and that the coexpression of NPGL and POMC may be present in the hypothalamus of male tilapia.

Molecular cloning, expressional analyses and functional identification of TRAIL in tilapia, Oreochromis niloticus.

The tumour necrosis factor superfamily (TNFSF) plays critical roles in tumour apoptosis, tissue morphogenesis and lineage determination. TNFSF10 (TRAIL or Apol-2) belongs to the tumour necrosis factor (TNF) cytokine family and induces rapid apoptosis in a wide variety of tumour cell lines upon binding to death-inducing signalling receptors. In this study, we identified TNFSF10 from Nile tilapia (Oreochromis niloticus) and found it was most closely related to Japanese pufferfish (Takifugu rubripes) TNFSF10. Amino acid identity between tilapia TNFSF10 and mandarin fish (Siniperca chuatsi) TRAIL was 69.2%. The highest expression of TNFSF10 mRNA was observed in the liver. In vitro studies showed that the mRNA expression of TNFSF10 was significantly stimulated by LPS in head kidney leucocytes, but remarkably inhibited by Poly I:C in spleen leucocytes. In vivo studies showed Streptococcus agalactiae infection significantly induced the mRNA expression of TNFSF10 in both the head kidney and spleen. The soluble recombinant protein Trx-TNFSF10 could induce cytotoxicity and apoptosis in HeLa cells with cycloheximide as a promoter. Taken together, these results in this study indicate that TNFSF10 may play important roles in the immune system of Nile tilapia.

Molecular Cloning and Functional Characterization of Three 5-HT Receptor Genes (HTR1B, HTR1E, and HTR1F) in Chickens.

The serotonin (5-hydroxytryptamine, 5-HT) signaling system is involved in a variety of physiological functions, including the control of cognition, reward, learning, memory, and vasoconstriction in vertebrates. Contrary to the extensive studies in the mammalian system, little is known about the molecular characteristics of the avian serotonin signaling network. In this study, we cloned and characterized the full-length cDNA of three serotonin receptor genes (HTR1B, HTR1E and HTR1F) in chicken pituitaries. Synteny analyses indicated that HTR1B, HTR1E and HTR1F were highly conserved across vertebrates. Cell-based luciferase reporter assays showed that the three chicken HTRs were functional, capable of binding their natural ligands (5-HT) or selective agonists (CP94253, BRL54443, and LY344864) and inhibiting intracellular cAMP production in a dose-dependent manner. Moreover, activation of these receptors could stimulate the MAPK/ERK signaling cascade. Quantitative real-time PCR analyses revealed that HTR1B, HTR1E and HTR1F were primarily expressed in various brain regions and the pituitary. In cultured chicken pituitary cells, we found that LY344864 could significantly inhibit the secretion of PRL stimulated by vasoactive intestinal peptide (VIP) or forskolin, revealing that HTR1F might be involved in the release of prolactin in chicken. Our findings provide insights into the molecular mechanism and facilitate a better understanding of the serotonergic modulation via HTR1B, HTR1E and HTR1F in avian species.

Microparticles and microplastics released from daily use of plastic feeding and water bottles and plastic injectors: potential risks to infants and children in China.

Daily use of plastic feeding and water bottles occur widely in China, and they could be sources for release of microplastics (MPs), which threaten the health of Chinese infants and children during daily usage. In this work, we investigated the use of polycarbonate (PC) and polypropylene (PP) for making water bottles (WBs) and polyphenylene sulfone resins (PPSU) for making feeding bottles (FBs), and we found that feeding bottles and water bottles released microparticles in amounts ranging from 53 to 393 particles/mL during 100 opening/closing cycles. The good linear regressions for plots of microparticles released vs. abrasion distance (r2 = 0.811) indicated that thick-necked bottles release more microparticles than thin-necked bottles. The brands and types of bottles (plastic vs. glass) influence microparticle release, and this indicates that high-quality plastic and glass bottles release fewer microparticles and are good for the health of infants and children. In addition to calcium stearate and silicone additives, the identified MPs account for 7.5 to 42.1% of released microparticles with different polymer types, sizes (from 20 to 500 µm) and shapes (cubic, spherical and irregular shapes). Additionally, an average of 1.74 MPs were released from an injection with a single-use plastic injector. Nevertheless, a number of microparticles and nanosized plastics were observed with all samples, suggesting that the health risks of micro- and nanosized particles to humans, especially babies and children, and the environment should be considered seriously.

Effects of neuropeptide Y as a feed additive on stimulating the growth of tilapia (Oreochromis niloticus) fed low fish meal diets.

Neuropeptide Y is known to stimulate food intake in fish. In this study, we investigated tilapia NPY (tNPY) both for its effects on the growth of tilapia (Oreochromis niloticus, GIFT) in low fish meal and for its thermal stability. Three diets were formulated containing 0, 3 and 10 % fish meal (NF, LF and HF). From these diets, six experimental diets were prepared by spraying either tNPY solution (0.3 µg/g feed) or distilled water (DW) onto the surface of formulated feeds (NF + DW, NF + tNPY, LF + DW, LF + tNPY, HF + DW and HF + tNPY). Tilapia were fed the six experimental diets for 8 weeks. Fish in the NF + tNPY, LF + tNPY and HF + tNPY groups showed increasing trends in the weight gain rate and specific growth rate compared to its corresponding control group. The feed coefficient of group HF + tNPY was significantly lower than that of the control group. The growth performance of the LF + tNPY approached that of the HF + DW group. The mRNA levels of npy in NF + tNPY were significantly higher than those in NF + DW. A field experiment in which tNPY was sprayed in feeds by the vacuum spray method with doses of 0, 0.2 and 0.4 µg/g feed was performed for three months, and the FBW of tilapia receiving tNPY at 0.2 and 0.4 µg/g feed was higher than that of the control group although not significantly. The bioactivity of tNPY was confirmed by its ability to reduce cAMP levels and activate the ERK1/2 pathway. These results demonstrated that tNPY could promote tilapia growth with oral administration low fish meal diets.

Melanocortin Receptor 4 (MC4R) Signaling System in Nile Tilapia.

The melanocortin receptor 4 (MC4R) signaling system consists of MC4R, MC4R ligands [melanocyte-stimulating hormone (MSH), adrenocorticotropin (ACTH), agouti-related protein (AgRP)], and melanocortin-2 receptor accessory protein 2 (MRAP2), and it has been proposed to play important roles in feeding and growth in vertebrates. However, the expression and functionality of this system have not been fully characterized in teleosts. Here, we cloned tilapia MC4R, MRAP2b, AgRPs (AgRP, AgRP2), and POMCs (POMCa1, POMCb) genes and characterized the interaction of tilapia MC4R with MRAP2b, AgRP, α-MSH, and ACTH in vitro. The results indicate the following. (1) Tilapia MC4R, MRAP2b, AgRPs, and POMCs share high amino acid identity with their mammalian counterparts. (2) Tilapia MRAP2b could interact with MC4R expressed in CHO cells, as demonstrated by Co-IP assay, and thus decrease MC4R constitutive activity and enhance its sensitivity to ACTH1-40. (3) As in mammals, AgRP can function as an inverse agonist and antagonist of MC4R, either in the presence or absence of MRAP2b. These data, together with the co-expression of MC4R, MRAP2b, AgRPs, and POMCs in tilapia hypothalamus, suggest that as in mammals, ACTH/α-MSH, AgRP, and MRAP2 can interact with MC4R to control energy balance and thus play conserved roles in the feeding and growth of teleosts.

Molecular identification, tissue distribution and in vitro functional analysis of growth hormone and its receptors in red-spotted grouper (Epinephelus akaara).

Red-spotted grouper (Epinephelus akaara) is one of the high economic value grouper species, however, the knowledge regarding its growth is limited. In this study, full-length cDNAs of growth hormone (gh) and its receptors (ghr1 and ghr2) were cloned from the pituitary and liver of red-spotted grouper, respectively. Tissue distribution analysis showed that gh mRNA was predominantly expressed in the pituitary. ghr1 mRNA was highly expressed in the liver, muscle, fat and gonad, while ghr2 mRNA expression was ubiquitously high in the peripheral tissues. However, the mRNA expression of both ghr isoforms was relatively low in the central nervous system. Secretory recombinant grouper GH (rgGH) was expressed in yeast Pichia pastoris and verified. HEK293T cells transiently transfected with the GHR isoforms were used to elucidate the receptor-mediated signaling pathways related to growth regulation. rgGH activated rapid phosphorylation of Janus kinase 2, signal transducer and activator of transcription 5 (STAT5) and extracellular signal-regulated protein kinase 1/2 through GHR1, but only STAT5 was phosphorylated via GHR2. rgGH strongly activated STAT5 phosphorylation and significantly stimulated ghr1, ghr2 and insulin-like growth factor (igf1, igf2) mRNA expression in primary cultured hepatocytes. Data showed that the recombinant protein rgGH played effects on igf1/2 mRNA expression via GHR-mediated signaling pathways. Our findings provide essential information about GH and GHRs characteristics in red-spotted grouper.

Mechanism of low concentrations of polystyrene microplastics influence the cytotoxicity of Ag ions to Escherichia coli.

Polystyrene microplastics (PSMPs) with different sizes, surface charges and aging statuses simulated field PSMPs and were applied to understand their cytotoxicity to Escherichia coli. The PSMPs hardly affected the viability, membrane integrity, ROS generation and ATPase activity of E. coli, and the cytotoxicity of field PSMPs is marginal and assumed to be overestimated. Low concentrations (1.0 mg L-1) of PSMPs dynamically affect the cytotoxicity of Ag+ to E. coli through various toxic mechanisms. PSMPs likely mitigated the cytotoxicity of Ag+ during the initial 24 h of co-exposure by protecting the cell membrane, inhibiting ROS generation and/or recovering ATPase activity (p < 0.05 or p < 0.01). During prolonged co-exposure for 48 h, nonfunctionalized polystyrene (PS-NF) still mitigated the cytotoxicity of Ag+ by protecting the integrity of the cell membrane, and aged PS-NF slightly affected cytotoxicity. PS-NH2 and PS-COOH intensified the cytotoxicity of Ag+ because PS markedly promoted ROS generation and inhibited ATPase activity. Thus, field PSMPs were assumed to exhibit marginal cytotoxicity to E. coli and can combine with surrounding Ag+ to modify the E. coli population levels and even the structure of aquatic ecosystems. Accordingly, the environmental and health risks of field PSMPs require further intensive investigation, and the combined toxicity effects of field PSMPs with Ag+ should be considered carefully due to their dynamic toxic effects and mechanisms.

Health risk assessment of trace elements exposure through the soil-plant (maize)-human contamination pathway near a petrochemical industry complex, Northeast China.

The trace elements contamination of agricultural soils near petrochemical industry complexes is a concern due to the risk of accumulating in food systems and subsequently affecting human health. We measured representative trace elements (Cu, Ni, Cr, Pb, Zn, Pb, Hg and As) through the soil-plant (maize)-human contamination pathway near a petrochemical industry complexes in an agricultural region from September 20 to 28, 2016. We found that the soil was mildly to moderately polluted by multiple trace elements, which was also confirmed by the contamination factor and enrichment factor values. Cd (enrichment factor = 2.28), Cu (2.75), Zn (1.85) and Pb (1.70) should be given more attention and prioritized over the other trace elements due to their higher potential risks. Furthermore, the trace elements contamination in maize grains was lower than the corresponding limits. The sequence of the transfer coefficient values was Zn > Cd > Cu > Hg > Ni > As > Cr > Pb. Maize grain safety was threatened mainly by Zn, Cd and Cu. There was no risk to humans through soil ingestion, while a potential health risk from maize grain consumption existed. Children were more sensitive than adults to the non-carcinogenic risks of maize grain consumption. Trace element As was found to be the priority metal for risk control. For carcinogenic risk, adults were more sensitive than children; As, Cr and Cd were the priority metals for risk control, with CRmaize values exceeding the risk threshold (1 × 10-4). Overall, strict, intensive monitoring, especially of Cr and Cd, and soil protection measures are needed to prevent any furthertrace elements contamination and to ensure food safety. This study also provides a reference for similar studies worldwide.

Promotion of Wound Healing and Prevention of Frostbite Injury in Rat Skin by Exopolysaccharide from the Arctic Marine Bacterium Polaribacter sp. SM1127.

Many marine microorganisms synthesize exopolysaccharides (EPSs), and some of these EPSs have been reported to have potential in different fields. However, the pharmaceutical potentials of marine EPSs are rarely reported. The EPS secreted by the Artic marine bacterium Polaribacter sp. SM1127 has good antioxidant activity, outstanding moisture-retention ability, and considerable protective property on human dermal fibroblasts (HDFs) at low temperature. Here, the effects of SM1127 EPS on skin wound healing and frostbite injury prevention were studied. Scratch wound assay showed that SM1127 EPS could stimulate the migration of HDFs. In the full-thickness cutaneous wound experiment of Sprague-Dawley (SD) rats, SM1127 EPS increased the wound healing rate and stimulated tissue repair detected by macroscopic observation and histologic examination, showing the ability of SM1127 EPS to promote skin wound healing. In the skin frostbite experiment of SD rats, pretreatment of rat skin with SM1127 EPS increased the rate of frostbite wound healing and promoted the repair of the injured skin significantly, indicating the good effect of SM1127 EPS on frostbite injury prevention. These results suggest the promising potential of SM1127 EPS in the pharmaceutical area to promote skin wound healing and prevent frostbite injury.

Dynamic cytotoxicity of ZnO nanoparticles and bulk particles to Escherichia coli: A view from unfixed ZnO particle:Zn2+ ratio.

ZnO nanoparticles (NPs) form binary mixtures of ZnO particles and released Zn2+ in the environment, and the quantitative contributions of these components to toxicity are still uncertain. Herein, quantitative contribution of ZnO particle and Zn2+ to cytotoxicity of ZnO NPs to Escherichia coli were determined during 48 h bioassay. The cytotoxicity and mechanisms of ZnO NPs were dynamic and affected by ionic strength, Fe3+, humic acid, and temperature due to the unfixed ZnO particle:Zn2+ ratio. ZnO NPs and ZnO bulk particles (BPs) had comparable cytotoxicity but distinct cytotoxic mechanisms. ZnO NPs cytotoxicity arises mainly from ZnO particles for 3 h and from Zn2+ afterwards (8-48 h). The cytotoxicity of ZnO BPs depends predominantly on ZnO particles for 12 h and on Zn2+ from 24 to 48 h. The cytotoxicity of ZnO NPs and BPs is partially attributable to Zn accumulation, and dependent on ZnO particle:Zn2+ ratio. The linear regressions of acute toxicity for ZnO NPs vs. BPs and Zn2+ yielded excellent r2 (0.9994 and 0.9998) from literature data and good r2 (≥ 0.714) under certain environmental factors, which can be applied to assess environmental risk of ZnO NPs. Furthermore, dynamic cytotoxicity and mechanisms should be seriously considered during the environmental risk assessment of ZnO NPs.

Dynamic nano-Ag colloids cytotoxicity to and accumulation by Escherichia coli: Effects of Fe3+, ionic strength and humic acid.

Released Ag ions or/and Ag particles are believed to contribute to the cytotoxicity of Ag nanomaterials, and thus, the cytotoxicity and mechanism of Ag nanomaterials should be dynamic in water due to unfixed Ag particle:Ag+ ratios. Our recent research found that the cytotoxicity of PVP-Ag nanoparticles is attributable to Ag particles alone in 3 hr bioassays, and shifts to both Ag particles and released Ag+ in 48 hr bioassays. Herein, as a continued study, the cytotoxicity and accumulation of 50 and 100 nm Ag colloids in Escherichia coli were determined dynamically. The cytotoxicity and mechanisms of nano-Ag colloids are dynamic throughout exposure and are derived from both Ag ions and particles. Ag accumulation by E. coli is derived mainly from extracellular Ag particles during the initial 12 hr of exposure, and thereafter mainly from intracellular Ag ions. Fe3+ accelerates the oxidative dissolution of nano-Ag colloids, which results in decreasing amounts of Ag particles and particle-related toxicity. Na+ stabilizes nano-Ag colloids, thereby decreasing the bioavailability of Ag particles and particle-related toxicity. Humic acid (HA) binds Ag+ to form Ag+-HA, decreasing ion-related toxicity and binding to the E. coli surface, decreasing particle-related toxicity. HA in complex conditions showed a stronger relative contribution to toxicity and accumulation than Na+ or Fe3+. The results highlighted the cytotoxicity and mechanism of nano-Ag colloids are dynamic and affected by environmental factors, and therefore exposure duration and water chemistry should be seriously considered in environmental and health risk assessments.