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1.
Tree Physiol ; 43(11): 1886-1902, 2023 11 13.
Article in English | MEDLINE | ID: mdl-37584475

ABSTRACT

The connections between the primary and secondary growth of trees allows better understanding of the dynamics of carbon sequestration in forest ecosystems. The relationship between primary and secondary growth of trees could change due to the diverging responses of meristems to climate warming. In this study, the bud phenology and radial growth dynamics of Qinghai spruce (Picea crassifolia) in arid and semi-arid areas of China in 2019 and 2020 were weekly monitored to analyze their response to different weather conditions and their links with carbon sink. Xylem anatomical traits (i.e. lumen radial diameter and cell wall thickness) were quantified along cell radial files after the end of xylem lignification to calculate the early-to-latewood transition date. Winter and early spring (January-March) were warmer in 2020 with a colder April compared with 2019. Precipitation in April-June was lower in 2020 than in 2019. In 2019, bud phenology occurred earlier, while the onset of xylem formation and the early-to-latewood transition date were delayed. The duration from the beginning of split bud and exposed shoot to the early-to-latewood transition date was positively correlated with the radial width of earlywood (accounting for ~80% of xylem width) and total xylem width. The longer duration of xylem cell division did not increase xylem cell production and radial width. Moreover, the duration from bud burst to the early-to-latewood transition date in 2020 was negatively linked with early phloem cell production as compared with 2019. Our findings suggest that warm conditions in winter and early spring promote the xylogenesis of Qinghai spruce, but might delay bud burst. However, the xylem width increments largely depend on the duration from bud burst to the start of latewood cell division rather than on the earlier xylogenesis and longer duration of xylem cell differentiation induced by warm conditions.


Subject(s)
Picea , Wood , Ecosystem , Xylem , Climate , Seasons , Trees
2.
Mol Plant Pathol ; 23(9): 1262-1277, 2022 09.
Article in English | MEDLINE | ID: mdl-35598295

ABSTRACT

Tomato brown rugose fruit virus (ToBRFV) is an emerging and rapidly spreading RNA virus that infects tomato and pepper, with tomato as the primary host. The virus causes severe crop losses and threatens tomato production worldwide. ToBRFV was discovered in greenhouse tomato plants grown in Jordan in spring 2015 and its first outbreak was traced back to 2014 in Israel. To date, the virus has been reported in at least 35 countries across four continents in the world. ToBRFV is transmitted mainly via contaminated seeds and mechanical contact (such as through standard horticultural practices). Given the global nature of the seed production and distribution chain, and ToBRFV's seed transmissibility, the extent of its spread is probably more severe than has been disclosed. ToBRFV can break down genetic resistance to tobamoviruses conferred by R genes Tm-1, Tm-2, and Tm-22 in tomato and L1 and L2 alleles in pepper. Currently, no commercial ToBRFV-resistant tomato cultivars are available. Integrated pest management-based measures such as rotation, eradication of infected plants, disinfection of seeds, and chemical treatment of contaminated greenhouses have achieved very limited success. The generation and application of attenuated variants may be a fast and effective approach to protect greenhouse tomato against ToBRFV. Long-term sustainable control will rely on the development of novel genetic resistance and resistant cultivars, which represents the most effective and environment-friendly strategy for pathogen control. TAXONOMY: Tomato brown rugose fruit virus belongs to the genus Tobamovirus, in the family Virgaviridae. The genus also includes several economically important viruses such as Tobacco mosaic virus and Tomato mosaic virus. GENOME AND VIRION: The ToBRFV genome is a single-stranded, positive-sense RNA of approximately 6.4 kb, encoding four open reading frames. The viral genomic RNA is encapsidated into virions that are rod-shaped and about 300 nm long and 18 nm in diameter. Tobamovirus virions are considered extremely stable and can survive in plant debris or on seed surfaces for long periods of time. DISEASE SYMPTOMS: Leaves, particularly young leaves, of tomato plants infected by ToBRFV exhibit mild to severe mosaic symptoms with dark green bulges, narrowness, and deformation. The peduncles and calyces often become necrotic and fail to produce fruit. Yellow blotches, brown or black spots, and rugose wrinkles appear on tomato fruits. In pepper plants, ToBRFV infection results in puckering and yellow mottling on leaves with stunted growth of young seedlings and small yellow to brown rugose dots and necrotic blotches on fruits.


Subject(s)
Plant Viruses , Solanum lycopersicum , Tobamovirus , Fruit , Solanum lycopersicum/genetics , Plant Viruses/genetics , RNA, Plant , RNA, Viral/genetics , Tobamovirus/genetics
3.
Tree Physiol ; 42(4): 754-770, 2022 04 07.
Article in English | MEDLINE | ID: mdl-35029689

ABSTRACT

Atmospheric nitrogen (N) deposition and increasing precipitation affect carbon sequestration in terrestrial ecosystems, but how these two concurrent global change variables affect xylem growth in trees (i.e., independently or interactively) remains unclear. We conducted novel experiments in central China to monitor the xylem growth in a dominant species (Quercus acutissima Caruth.) in response to N addition (CN), supplemental precipitation (CW) or both treatments (CNW), compared with untreated controls (C). Measurements were made at weekly intervals during 2014-15. We found that supplemental precipitation significantly enhanced xylem growth in the dry spring of 2015, indicating a time-varying effect of increased precipitation on intra-annual xylem growth. Elevated N had no significant effect on xylem increment, xylem growth rate, and lumen diameters and potential hydraulic conductivity (Ks) of earlywood vessels, but Ks with elevated N was significantly negatively related to xylem increment. The combination of additional N and supplemental precipitation suppressed the positive effect of supplemental precipitation on xylem increment in the dry spring of 2015. These findings indicated that xylem width was more responsive to supplemental precipitation than to increasing N in a dry early growing season; the positive effect of supplemental precipitation on xylem growth could be offset by elevated N resources. The negative interactive effect of N addition and supplemental precipitation also suggested that increasing N deposition and precipitation in the future might potentially affect carbon sequestration of Q. acutissima during the early growing season in central China. The effects of N addition and supplemental precipitation on tree growth are complex and might vary depending on the growth period and local climatic conditions. Therefore, future models of tree growth need to consider multiple-time scales and local climatic conditions when simulating and projecting global change.


Subject(s)
Quercus , Ecosystem , Nitrogen , Quercus/physiology , Trees , Xylem/physiology
4.
Tree Physiol ; 42(2): 317-324, 2022 02 09.
Article in English | MEDLINE | ID: mdl-34505152

ABSTRACT

Auxin is involved in various developmental processes of plants, including cell division in cambium and xylem differentiation. However, most studies linking auxin and xylem cell production are performed in environments with a strong seasonality (i.e., temperate and boreal climates). The temporal dynamics of auxin and cambial activity of subtropical trees remain basically unknown. In this study, we sampled four microcores weekly in three individuals of Chinese red pine (Pinus massoniana Lamb.) from February to December 2015-16 to compare xylem formation with auxin concentration in subtropical China. During the entire period of sampling, the number of cambial cells varied from 2 to 7, while the number of cells in the enlarging zone ranged from 1 to 4 and from 1 to 5 in the wall-thickening zone. In 2015, the average auxin concentration was 3.46 ng g-1, with 33 xylem cells being produced at the end of the year. In 2016, a lower auxin concentration (2.59 ng g-1) corresponded to a reduced annual xylem production (13.7 cells). No significant relationship between auxin concentration and number of xylem cells in differentiation was found at the weekly scale. Unlike in boreal and temperate forests, the lack of wood formation seasonality in subtropical forests makes it more difficult to reveal the relationship between auxin concentration and number of xylem cells in differentiation at the intra-annual scale. The frequent and repeated samplings might have reduced auxin concentration in the developing cambium and xylem, resulting in a lower xylem cell production.


Subject(s)
Pinus , Cambium , China , Forests , Indoleacetic Acids , Xylem
5.
Molecules ; 26(8)2021 Apr 08.
Article in English | MEDLINE | ID: mdl-33917726

ABSTRACT

This paper studies the influence of hydroxyethyl methyl cellulose (HEMC) on the properties of calcium sulfoaluminate (CSA) cement mortar. In order to explore the applicability of different HEMCs in CSA cement mortars, HEMCs with higher and lower molar substitution (MS)/degree of substitution (DS) and polyacrylamide (PAAm) modification were used. At the same time, two kinds of CSA cements with different contents of ye'elimite were selected. Properties of cement mortar in fresh and hardened states were investigated, including the fluidity, consistency and water-retention rate of fresh mortar and the compressive strength, flexural strength, tensile bond strength and dry shrinkage rate of hardened mortar. The porosity and pore size distribution were also analyzed by mercury intrusion porosimetry (MIP). Results show that HEMCs improve the fresh state properties and tensile bond strength of both types of CSA cement mortars. However, the compressive strength of CSA cement mortars is greatly decreased by the addition of HEMCs, and the flexural strength is decreased slightly. The MIP measurement shows that HEMCs increase the amount of micron-level pores and the porosity. The HEMCs with different MS/DS have different effects on the improvement of tensile bond strength in different CSA cement mortars. PAAm modification can improve the tensile bond strength of HEMC-modified CSA cement mortar.

6.
Pathogens ; 10(1)2021 Jan 07.
Article in English | MEDLINE | ID: mdl-33430364

ABSTRACT

Salmonella enterica subsp. enterica serotype Enteritidis (SE) is recognized as a major cause of human salmonellosis worldwide, and most human salmonellosis is due to the consumption of contaminated poultry meats and poultry byproducts. Whole-genome sequencing (data were obtained from 96 SE isolates from poultry sources, including an integrated broiler supply chain, farms, slaughterhouses, chicken transporting trucks, and retail chicken meats in South Korea during 2010-2017. Antimicrobial resistance and virulence genes were investigated using WGS data, and the phylogenetic relationship of the isolates was analyzed using single-nucleotide polymorphism (SNP) typing and core genome multilocus sequence typing (cgMLST). All isolates carried aminoglycoside resistance genes, aac (6')- Iaa, and 56 isolates carried multiple antimicrobial resistance genes. The most frequent virulence gene profile, pef-fim-sop-inv.-org-sip-spa-sif-fli-flg-hil-ssa-sse-prg-pag-spv, was found in 90 isolates. The SNP analysis provided a higher resolution than the cgMLST analysis, but the cgMLST analysis was highly congruent with the SNP analysis. The phylogenetic results suggested the presence of resident SE within the facility of processing plants, environments of slaughterhouses, and the integrated broiler supply chain, and the phylogenetically related isolates were found in retail meats. In addition, the SE isolates from different origins showed close genetic relationships indicating that these strains may have originated from a common source. This study could be valuable reference data for future traceback investigations in South Korea.

7.
J Colloid Interface Sci ; 588: 378-383, 2021 Apr 15.
Article in English | MEDLINE | ID: mdl-33422786

ABSTRACT

Transition metal dichalcogenides (TMDs) have emerged as a promising material in the energy field due to their unique structural arrangement. In this work, ordered flower-like WSe2 nanosheet was synthesized through simple one-step hydrothermal method, and its cathode application for rechargeable Mg-ion batteries was assessed. The WSe2 cathode exhibits a high reversible capacity above 265 mAh g-1 at 50 mA g-1, excellent cycling life of 90% initial capacitance that can be ceaselessly harvested for 100 cycles at 50 mA g-1, and superior rate capability of 70% initial capacitance maintained even at the current density of 500 mA g-1. This work paves the way for the application of WSe2 cathode in Mg-ion and other rechargeable batteries.

8.
J Colloid Interface Sci ; 585: 12-19, 2021 Mar.
Article in English | MEDLINE | ID: mdl-33279694

ABSTRACT

Transition metal dichalcogenides (TMDs) have been considered as the promising energy storage materials due to their unique crystalline structure. In this work, the VSe2 nanoparticles are vertically anchored on N-doping carbon (NC) hollow nanosphere (VSe2@NC) for aqueous energy application. The electrochemical measurements indicate that the VSe2@NC electrode exhibits outstanding electrochemical properties with high specific capacitance and excellent cycling life. Moreover, the asymmetric supercapacitor was assembled by using VSe2@NC cathode and activated carbon anode. It shows high energy density of 85.41 Wh Kg-1 at a power density of 701.99 W Kg-1, and high-stable cycling performance of 90% retention after 2000 cycles. The superior properties are attributed to the particular hollow structure design, which accommodates both the high specific capacity of VSe2 and the desired electrical conductivity of N-doping carbon sphere template.

10.
mSystems ; 5(5)2020 Sep 08.
Article in English | MEDLINE | ID: mdl-32900871

ABSTRACT

Microorganisms and their communities on foods are important determinants and indicators of food safety and quality. Despite growing interests in studying food and food-related microbiomes, how effective and practical it is to glean various food safety and quality information from food commodity microbiomes remains underinvestigated. Microbiomes of retail chicken breast from 4 processing establishments in 3 major U.S. broiler production states displayed longitudinal consistency over 7 months and cross-sectional distinctiveness associated with individual processing environments. Packaging type and processing environment but not antibiotic usage and seasonality affected composition and diversity of the microbiomes. Low abundances of antimicrobial resistance genes were found on chicken breasts, and no significant resistome difference was observed between antibiotic-free and conventional products. Benchmarked by culture enrichment, shotgun metagenomics sequencing delivered sensitive and specific detection of Salmonella enterica from chicken breasts.IMPORTANCE Chicken has recently overtaken beef as the most-consumed meat in the United States. The growing popularity of chicken is accompanied by frequent occurrences of foodborne pathogens and increasing concerns over antibiotic usage. Our study represents a proof-of-concept investigation into the possibility and practicality of leveraging microbiome-informed food safety and quality. Through a longitudinal and cross-sectional survey, we established the chicken microbiome as a robust and multifaceted food microbiology attribute that could provide a variety of safety and quality information and retain systematic signals characteristic of overall processing environments.

11.
Proc Natl Acad Sci U S A ; 117(34): 20645-20652, 2020 08 25.
Article in English | MEDLINE | ID: mdl-32759218

ABSTRACT

Wood formation consumes around 15% of the anthropogenic CO2 emissions per year and plays a critical role in long-term sequestration of carbon on Earth. However, the exogenous factors driving wood formation onset and the underlying cellular mechanisms are still poorly understood and quantified, and this hampers an effective assessment of terrestrial forest productivity and carbon budget under global warming. Here, we used an extensive collection of unique datasets of weekly xylem tissue formation (wood formation) from 21 coniferous species across the Northern Hemisphere (latitudes 23 to 67°N) to present a quantitative demonstration that the onset of wood formation in Northern Hemisphere conifers is primarily driven by photoperiod and mean annual temperature (MAT), and only secondarily by spring forcing, winter chilling, and moisture availability. Photoperiod interacts with MAT and plays the dominant role in regulating the onset of secondary meristem growth, contrary to its as-yet-unquantified role in affecting the springtime phenology of primary meristems. The unique relationships between exogenous factors and wood formation could help to predict how forest ecosystems respond and adapt to climate warming and could provide a better understanding of the feedback occurring between vegetation and climate that is mediated by phenology. Our study quantifies the role of major environmental drivers for incorporation into state-of-the-art Earth system models (ESMs), thereby providing an improved assessment of long-term and high-resolution observations of biogeochemical cycles across terrestrial biomes.


Subject(s)
Tracheophyta/growth & development , Wood/growth & development , Xylem/growth & development , Climate , Climate Change , Ecosystem , Forests , Global Warming , Models, Biological , Photoperiod , Seasons , Temperature , Tracheophyta/genetics , Trees/growth & development
13.
Appl Environ Microbiol ; 86(13)2020 06 17.
Article in English | MEDLINE | ID: mdl-32358002

ABSTRACT

Food safety is a new area for novel applications of metagenomics analysis, which not only can detect and subtype foodborne pathogens in a single workflow but may also produce additional information with in-depth analysis capabilities. In this study, we applied a quasimetagenomic approach by combining short-term enrichment, immunomagnetic separation (IMS), multiple-displacement amplification (MDA), and nanopore sequencing real-time analysis for simultaneous detection of Salmonella and Escherichia coli in wheat flour. Tryptic soy broth was selected for the 12-h enrichment of samples at 42°C. Enrichments were subjected to IMS using beads capable of capturing both Salmonella and E. coli MDA was performed on harvested beads, and amplified DNA fragments were subjected to DNA library preparation for sequencing. Sequencing was performed on a portable device with real-time basecalling adaptability, and resulting sequences were subjected to two parallel pipelines for further analysis. After 1 h of sequencing, the quasimetagenomic approach could detect all targets inoculated at approximately 1 CFU/g flour to the species level. Discriminatory power was determined by simultaneous detection of dual inoculums of Salmonella and E. coli, absence of detection in control samples, and consistency in microbial flora composition of the same flour samples over several rounds of experiments. The total turnaround time for detection was approximately 20 h. Longer sequencing for up to 15 h enabled serotyping for many of the samples with more than 99% genome coverage, which could be subjected to other appropriate genetic analysis pipelines in less than a total of 36 h.IMPORTANCE Enterohemorrhagic Escherichia coli (EHEC) and Salmonella are of serious concern in low-moisture foods, including wheat flour and its related products, causing illnesses, outbreaks, and recalls. The development of advanced detection methods based on molecular principles of analysis is essential to incorporate into interventions intended to reduce the risk from these pathogens. In this work, a quasimetagenomic method based on real-time sequencing analysis and assisted by magnetic capture and DNA amplification was developed. This protocol is capable of detecting multiple Salmonella and/or E. coli organisms in the sample within less than a day, and it can also generate sufficient whole-genome sequences of the target organisms suitable for subsequent bioinformatics analysis. Multiplex detection and identification were accomplished in less than 20 h and additional whole-genome analyses of different nature were attained within 36 h, in contrast to the several days required in previous sequencing pipelines.


Subject(s)
Escherichia coli/isolation & purification , Flour/microbiology , Food Microbiology/methods , Salmonella enterica/isolation & purification , Serotyping/methods , Escherichia coli/classification , Immunomagnetic Separation/methods , Magnetic Phenomena , Metagenomics/methods , Nanopore Sequencing/methods , Salmonella enterica/classification , Triticum
14.
J Food Sci ; 84(11): 3275-3283, 2019 Nov.
Article in English | MEDLINE | ID: mdl-31602667

ABSTRACT

This research aimed to compare the effects of monosodium glutamate (MSG) and its alternatives on sensory characteristics of chicken soup. High-performance liquid chromatography analysis was carried out to quantify umami substances in potential MSG alternatives. Two mushroom extracts (CE and MC), one tomato extract (TC), and one yeast extract (YE) powders were selected due to their high equivalent umami concentration (EUC). These extracts together with MSG were then applied individually at four different levels (CE, MC, TC, MSG: 0.05%, 0.1%, 0.2%, 0.4%; YE: 0.0125%, 0.025%, 0.05%, 0.1%) in chicken soup in order to compare their impact on major sensory attributes using the degree of difference from control (DODC) test. Our results showed that all four extracts at all the usage levels exhibited an enhancement effect on the overall flavor, meaty flavor, saltiness, and umami taste. The extent of enhancement depended on the type of the alternative and its usage level. Higher levels of MSG alternatives (except YE) suppressed the chicken flavor. YE had similar enhancement effects as MSG on umami and salty tastes already at lower usage levels. At the lowest concentration, TC showed a stronger enhancement effect than MSG, but its effect on most attributes decreased as the usage dose increased. Compared to CE, the other mushroom extract MC resembled MSG at most levels. Overall, the closest synergistic effect in chicken soup was noted with 0.1% MSG, 0.1% MC, and 0.025% YE. PRACTICAL APPLICATION: This study compared the enhancement effects of MSG and selected alternatives in chicken soup. Results will help food manufacturers who would like to replace MSG with natural umami substances in soup products to enhance flavor and reduce sodium chloride.


Subject(s)
Agaricales/chemistry , Flavoring Agents/analysis , Plant Extracts/analysis , Sodium Glutamate/analysis , Solanum lycopersicum/chemistry , Animals , Chickens , Humans , Sodium Chloride/analysis , Taste
15.
Appl Environ Microbiol ; 85(24)2019 12 15.
Article in English | MEDLINE | ID: mdl-31585993

ABSTRACT

Single-nucleotide polymorphisms (SNPs) are widely used for whole-genome sequencing (WGS)-based subtyping of foodborne pathogens in outbreak and source tracking investigations. Mobile genetic elements (MGEs) are commonly present in bacterial genomes and may affect SNP subtyping results if their evolutionary history and dynamics differ from that of the bacterial chromosomes. Using Salmonella enterica as a model organism, we surveyed major categories of MGEs, including plasmids, phages, insertion sequences, integrons, and integrative and conjugative elements (ICEs), in 990 genomes representing 21 major serotypes of S. enterica We evaluated whether plasmids and chromosomal MGEs affect SNP subtyping with 9 outbreak clusters of different serotypes found in the United States in 2018. The median total length of chromosomal MGEs accounted for 2.5% of a typical S. enterica chromosome. Of the 990 analyzed S. enterica isolates, 68.9% contained at least one assembled plasmid sequence. The median total length of assembled plasmids in these isolates was 93,671 bp. Plasmids that carry high densities of SNPs were found to substantially affect both SNP phylogenies and SNP distances among closely related isolates if they were present in the reference genome for SNP subtyping. In comparison, chromosomal MGEs were found to have limited impact on SNP subtyping. We recommend the identification of plasmid sequences in the reference genome and the exclusion of plasmid-borne SNPs from SNP subtyping analysis.IMPORTANCE Despite increasingly routine use of WGS and SNP subtyping in outbreak and source tracking investigations, whether and how MGEs affect SNP subtyping has not been thoroughly investigated. Besides chromosomal MGEs, plasmids are frequently entangled in draft genome assemblies and yet to be assessed for their impact on SNP subtyping. This study provides evidence-based guidance on the treatment of MGEs in SNP analysis for Salmonella to infer phylogenetic relationship and SNP distance between isolates.


Subject(s)
Interspersed Repetitive Sequences/genetics , Polymorphism, Single Nucleotide , Salmonella enterica/classification , Salmonella enterica/genetics , Chromosomes, Bacterial , Disease Outbreaks , Genome, Bacterial , Humans , Phylogeny , Plasmids/isolation & purification , Serogroup , Whole Genome Sequencing
16.
Appl Environ Microbiol ; 85(23)2019 12 01.
Article in English | MEDLINE | ID: mdl-31540993

ABSTRACT

SeqSero, launched in 2015, is a software tool for Salmonella serotype determination from whole-genome sequencing (WGS) data. Despite its routine use in public health and food safety laboratories in the United States and other countries, the original SeqSero pipeline is relatively slow (minutes per genome using sequencing reads), is not optimized for draft genome assemblies, and may assign multiple serotypes for a strain. Here, we present SeqSero2 (github.com/denglab/SeqSero2; denglab.info/SeqSero2), an algorithmic transformation and functional update of the original SeqSero. Major improvements include (i) additional sequence markers for identification of Salmonella species and subspecies and certain serotypes, (ii) a k-mer based algorithm for rapid serotype prediction from raw reads (seconds per genome) and improved serotype prediction from assemblies, and (iii) a targeted assembly approach for specific retrieval of serotype determinants from WGS for serotype prediction, new allele discovery, and prediction troubleshooting. Evaluated using 5,794 genomes representing 364 common U.S. serotypes, including 2,280 human isolates of 117 serotypes from the National Antimicrobial Resistance Monitoring System, SeqSero2 is up to 50 times faster than the original SeqSero while maintaining equivalent accuracy for raw reads and substantially improving accuracy for assemblies. SeqSero2 further suggested that 3% of the tested genomes contained reads from multiple serotypes, indicating a use for contamination detection. In addition to short reads, SeqSero2 demonstrated potential for accurate and rapid serotype prediction directly from long nanopore reads despite base call errors. Testing of 40 nanopore-sequenced genomes of 17 serotypes yielded a single H antigen misidentification.IMPORTANCE Serotyping is the basis of public health surveillance of Salmonella It remains a first-line subtyping method even as surveillance continues to be transformed by whole-genome sequencing. SeqSero allows the integration of Salmonella serotyping into a whole-genome-sequencing-based laboratory workflow while maintaining continuity with the classic serotyping scheme. SeqSero2, informed by extensive testing and application of SeqSero in the United States and other countries, incorporates important improvements and updates that further strengthen its application in routine and large-scale surveillance of Salmonella by whole-genome sequencing.


Subject(s)
Genome, Bacterial , Salmonella/genetics , Serotyping/methods , Whole Genome Sequencing , Serogroup , Serotyping/instrumentation , Software
17.
Sci Total Environ ; 697: 134109, 2019 Dec 20.
Article in English | MEDLINE | ID: mdl-31476511

ABSTRACT

In this work, in-situ remediation of sediment was carried out by combining various methods. The results showed that the treatment effect of Calcium nitrate + composite functional microorganisms + Low-DO (dissolved oxygen) aeration (CN/CFM/LDA) was the best, in which 2.5 g calcium nitrate, 1 g functional bacteria and intermittent aeration (0.1 m3/h, 3 h per day) were utilized for the remediation of 500 g sediments within 40-day experimental period. The DO and oxidation reduction potential (ORP) in overlying water have been improved from 3.23 mg/L to 4.4 mg/L and 25.8 mV to 112.4 mV, respectively. The release fluxes of ammonia nitrogen (NH4+-N), nitrite nitrogen (NO2--N) and nitrate nitrogen (NO3--N) were respectively reduced by 30.51%, 13.11% and 77.45% compared with the control and the removal rate of the acid volatile sulfide (AVS) in sediments was 94.14% compared with the original sample. The results of high-throughput sequencing show that the dominant bacterial community in CN/CFM/LDA was transformed into Proteobacteria (relative abundance of 74.17%) at the phylum level and Thiobacillus (relative abundance of 38.52%) at the genus level. The results of 16S functional prediction indicated that the remediation method can enhance the numbers of microbial key enzymes (92360) in the nitrification and denitrification process, where Low-DO aeration can mediate the growth of denitrifying bacteria and promote the performance of key enzymes. In conclusion, the experimental results show that the use of calcium nitrate and composite functional microorganisms under low-DO regulation has a promising remediation effect on sediments of black-malodorous water.


Subject(s)
Calcium Compounds/chemistry , Environmental Restoration and Remediation/methods , Nitrates/chemistry , Water Pollutants, Chemical/metabolism , Bacteria , Denitrification , Nitrification , Water Pollutants, Chemical/analysis
18.
Int J Biometeorol ; 63(12): 1631-1640, 2019 Dec.
Article in English | MEDLINE | ID: mdl-31385094

ABSTRACT

There is evidence that the ongoing climate change is happening through nighttime rather than daytime warming. How such a daily-asymmetric warming modifies plant phenology is still unclear. We investigated the effects of asymmetric warming on bud break by daily monitoring seedlings belonging to 26 black spruce [Picea mariana (Mill.) BSP.] and 15 balsam fir [Abies balsamea (L.) Mill.] provenances from the native range in Canada. Seedlings were subjected to either daytime or nighttime warming in three growth chambers at temperatures ranging between 10 and 24 °C. On average, a warming of 4 °C advanced the timings of bud break in both species by 2.4 days, with the later phases being more sensitive to the treatment. Bud break of both species responded more strongly to daytime warming, with the bud break occurred 1.2 and 3.2 days earlier under daytime than nighttime warming in black spruce and balsam fir, respectively. A marked ecotypic differentiation was only observed in black spruce that originated from provenances distributed broadly across Canada, with seedlings from the warmest provenance completing bud break 8.3 days later than those from the coldest one. However, no significant effect of provenance was observed for balsam fir, the narrowly distributed species. Overall, the above results suggest that a higher temporal resolution such as temperatures during daytime and nighttime, and higher spatial resolution should be taken into account to improve the accuracy of phenological model predictions under global change scenarios. Phenological models based on daily average temperature should take into account the diverging impacts of asymmetric warming on plant phenology. Our findings may indicate that the influence of warming on plant phenology may be less dramatic than expected.


Subject(s)
Abies , Picea , Canada , Climate Change , Seasons , Seedlings , Temperature
19.
Foods ; 8(2)2019 Feb 14.
Article in English | MEDLINE | ID: mdl-30769808

ABSTRACT

Soup manufacturers are removing monosodium glutamate (MSG) to meet consumer demand for natural ingredients. This research investigated the influence of MSG and its substitutes (yeast extract: YE; mushroom concentrate: MC; tomato concentrate: TC) on clear chicken soup with 0.4% sodium chloride (salt) by comparing sensory attributes and consumer acceptability among each other, and to a chicken soup sample containing 0.5% salt (Salt 0.5%). The soup with 0.4% salt without enhancers was designated as the control. Corresponding list of ingredients was also presented to consumers to study the effects on consumer expectations about chicken soup products. Our results showed that MSG and its substitutes significantly (P < 0.05) enhanced the sensory properties of chicken soup. These flavor enhancers also achieved statistically same or stronger improvement in overall flavor, meaty flavor, chicken flavor and umami taste when compared to Salt 0.5% sample. Consumers significantly preferred MSG 0.1%, YE 0.025%, and Salt 0.5% samples than others. Compared to MC and TC samples, less consumers perceived MSG and YE samples as "free of artificial" and "natural" with lower consumption interest. Claims about artificial/natural ingredients were attractive selling points for chicken soups, but good sensory appealing was the most important attribute linearly affecting consumer satisfactions.

20.
Emerg Infect Dis ; 25(1): 82-91, 2019 01.
Article in English | MEDLINE | ID: mdl-30561314

ABSTRACT

Increasingly, routine surveillance and monitoring of foodborne pathogens using whole-genome sequencing is creating opportunities to study foodborne illness epidemiology beyond routine outbreak investigations and case-control studies. Using a global phylogeny of Salmonella enterica serotype Typhimurium, we found that major livestock sources of the pathogen in the United States can be predicted through whole-genome sequencing data. Relatively steady rates of sequence divergence in livestock lineages enabled the inference of their recent origins. Elevated accumulation of lineage-specific pseudogenes after divergence from generalist populations and possible metabolic acclimation in a representative swine isolate indicates possible emergence of host adaptation. We developed and retrospectively applied a machine learning Random Forest classifier for genomic source prediction of Salmonella Typhimurium that correctly attributed 7 of 8 major zoonotic outbreaks in the United States during 1998-2013. We further identified 50 key genetic features that were sufficient for robust livestock source prediction.


Subject(s)
Foodborne Diseases/epidemiology , Salmonella Infections/epidemiology , Salmonella typhimurium/genetics , Animals , Case-Control Studies , Disease Outbreaks , Epidemiological Monitoring , Foodborne Diseases/microbiology , Genomics , Humans , Livestock/microbiology , Phylogeny , Retrospective Studies , Salmonella Infections/microbiology , Salmonella typhimurium/isolation & purification , United States/epidemiology , Whole Genome Sequencing , Zoonoses
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