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1.
The dengue fever epidemic in Guangzhou may have been affected by the Coronavirus Disease 2019 (COVID-19) pandemic. The number of dengue cases dropped drastically in 2020, and there have been only 2 local cases, suggesting that dengue has not become endemic in Guangzhou.Guangzhou is located on the southeast coast of China and is the country’s third largest city. Since 1978, outbreaks of dengue fever have occurred intermittently in this city. In the past decade, the number of reported dengue cases reached more than 1,000 in 2013, 2014, 2018, and 2019, with 37,385 cases reported in 2014 alone. Therefore, dengue fever is a major public health concern in Guangzhou, and there is a continuing argument that it is endemic in Guangzhou [1–3].The numbers of dengue cases from 2017 to 2020 are shown in Table 1. In 2020, the total and local case numbers dropped dramatically compared to the previous years. With a high proportion of imported cases (n = 32, 94.12%), the proportion of local cases (n = 2, 5.88%) was considerably low in 2020. All the prevention and control strategies for dengue, including issuing public education messages, preventing further mosquito bites in patients, cleaning vector breeding sites, and using pesticides, were similar during these years. Additionally, dengue, as a mosquito-borne viral infectious disease, is closely related to mosquito density. The mosquito ovitrap index (MOI), which is the proportion of positive mosquito ovitraps, is usually used to indicate mosquito density. The MOI in 2017, 2018, and 2019 was 7.073 ± 1.016, 9.657 ± 1.307, and 8.464 ± 0.961, respectively. The average MOI was 8.398 ± 0.648 from 2017 to 2019 in Guangzhou. The MOI in 2020 was 7.135 ± 0.786, which remained at the median risk level. Therefore, the abnormal decline in dengue cases could not be attributed to the change in mosquito density in 2020.Table 1Numbers and percentages of dengue cases from 2017 to 2019.
Open in a separate windowIn 2020, the 14-day quarantine in a designated hotel for international travelers to curb the spread of Coronavirus Disease 2019 (COVID-19) was an important public health intervention. People had to remain indoors except for medical care needs. All imported dengue cases were identified during their quarantine periods. No secondary case related to the imported cases was reported. This may be because Aedes albopictus, which is the major vector of dengue in Guangzhou, bites aggressively during the day outdoors. The chance of being bitten by A. albopictus was reduced by staying all day indoors. Moreover, some research revealed that viremia occurred 6 to 18 hours before symptoms appeared and lasted as long as 12 days [4]. After the 14-day quarantine, viremia had almost subsided. Therefore, imported dengue cases were unlikely to be transmitted. The impact of imported dengue cases was limited by the quarantine, which provided a rare opportunity to identify the local epidemic.The epidemiology investigation showed that the 2 local cases, who were living in the same building, had no travel history outside Guangzhou in 2020 and had symptoms successively. Two dengue virus serotype 2 (DENV-2) strains were isolated from them. The envelope gene sequences were obtained and deposited in GenBank under accession numbers and MW295818. Reference sequences, which were downloaded from GenBank, and sequences of Guangzhou strains identified in the previous years, were used to construct a phylogenetic tree. The 2 isolated strains in 2020 were identical. The tree ( MW345921Fig 1) shows that the 2 strains belonged to the Malaysia/Indian subcontinent genotype, which was the prevailing genotype in Guangzhou [5]. However, they were neither identical with nor derived from the Guangzhou strains obtained from the previous years. Using the Basic Local Alignment Search Tool in GenBank, the 2 strains were found to be highly similar to those identified in Zhejiang (China), Singapore, and Guangdong (China) in 2017. These results imply that the local cases may be secondary to some undiscovered cases imported from other cities in China, as no restriction and quarantine was imposed for domestic travels.Open in a separate windowFig 1Maximum-likelihood phylogenetic tree shows the evolutionary relationships of DENV-2 detected in the sera of 2 local cases along with 45 other sequences.The reference sequences are named using the GenBank accession number, country, and year. The sequences of strains isolated in Guangzhou are named using the GenBank accession number, year, and our lab number. Bootstrap support values are shown in the notes. Strains isolated in 2020 are indicated with a black triangle.When the impact of imported dengue cases was limited by quarantine, dengue did not spread in Guangzhou during 2020, with the MOI still at median risk level and without any changes in the prevention and control strategies. Moreover, serotype 1 had been prevalent in Guangzhou since 2011 [6,7]. However, there was no local infection of serotype 1 detected in 2020. These observations may provide further evidence that dengue fever is not endemic in Guangzhou.In conclusion, the number of dengue cases decreased during the COVID-19 epidemic in Guangzhou in 2020. Thus, we believe that dengue fever is not endemic in Guangzhou. 相似文献
Year | 2017 | 2018 | 2019 | 2020 |
Total cases | 944 | 1,295 | 1,655 | 34 |
Imported cases(percentage) | 69 (7.31%) | 96 (7.41%) | 270 (16.31%) | 32 (94.12%) |
Local cases (percentage) | 875 (92.69%) | 1,199 (92.59%) | 1,385 (83.69%) | 2 (5.88%) |
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Vincent Chochois John P. Vogel Gregory J. Rebetzke Michelle Watt 《Plant physiology》2015,168(3):953-967
Seedling roots enable plant establishment. Their small phenotypes are measured routinely. Adult root systems are relevant to yield and efficiency, but phenotyping is challenging. Root length exceeds the volume of most pots. Field studies measure partial adult root systems through coring or use seedling roots as adult surrogates. Here, we phenotyped 79 diverse lines of the small grass model Brachypodium distachyon to adults in 50-cm-long tubes of soil with irrigation; a subset of 16 lines was droughted. Variation was large (total biomass, ×8; total root length [TRL], ×10; and root mass ratio, ×6), repeatable, and attributable to genetic factors (heritabilities ranged from approximately 50% for root growth to 82% for partitioning phenotypes). Lines were dissected into seed-borne tissues (stem and primary seminal axile roots) and stem-borne tissues (tillers and coleoptile and leaf node axile roots) plus branch roots. All lines developed one seminal root that varied, with branch roots, from 31% to 90% of TRL in the well-watered condition. With drought, 100% of TRL was seminal, regardless of line because nodal roots were almost always inhibited in drying topsoil. Irrigation stimulated nodal roots depending on genotype. Shoot size and tillers correlated positively with roots with irrigation, but partitioning depended on genotype and was plastic with drought. Adult root systems of B. distachyon have genetic variation to exploit to increase cereal yields through genes associated with partitioning among roots and their responsiveness to irrigation. Whole-plant phenotypes could enhance gain for droughted environments because root and shoot traits are coselected.Adult plant root systems are relevant to the size and efficiency of seed yield. They supply water and nutrients for the plant to acquire biomass, which is positively correlated to the harvest index (allocation to seed grain), and the stages of flowering and grain development. Modeling in wheat (Triticum aestivum) suggested that an extra 10 mm of water absorbed by such adult root systems during grain filling resulted in an increase of approximately 500 kg grain ha−1 (Manschadi et al., 2006). This was 25% above the average annual yield of wheat in rain-fed environments of Australia. This number was remarkably close to experimental data obtained in the field in Australia (Kirkegaard et al., 2007). Together, these modeling and field experiments have shown that adult root systems are critical for water absorption and grain yield in cereals, such as wheat, emphasizing the importance of characterizing adult root systems to identify phenotypes for productivity improvements.Most root phenotypes, however, have been described for seedling roots. Seedling roots are essential for plant establishment, and hence, the plant’s potential to set seed. For technical reasons, seedlings are more often screened than adult plants because of the ease of handling smaller plants and the high throughput. Seedling-stage phenotyping may also improve overall reproducibility of results because often, growth media are soil free. Seedling soil-free root phenotyping conditions are well suited to dissecting fine and sensitive mechanisms, such as lateral root initiation (Casimiro et al., 2003; Péret et al., 2009a, 2009b). A number of genes underlying root processes have been identified or characterized using seedlings, notably with the dicotyledonous models Arabidopsis (Arabidopsis thaliana; Mouchel et al., 2004; Fitz Gerald et al., 2006; Yokawa et al., 2013) and Medicago truncatula (Laffont et al., 2010) and the cereals maize (Zea mays; Hochholdinger et al., 2001) and rice (Oryza sativa; Inukai et al., 2005; Kitomi et al., 2008).Extrapolation from seedling to adult root systems presents major questions (Hochholdinger and Zimmermann, 2008; Chochois et al., 2012; Rich and Watt, 2013). Are phenotypes in seedling roots present in adult roots given developmental events associated with aging? Is expression of phenotypes correlated in seedling and adult roots if time compounds effects of growth rates and growth conditions on roots? Watt et al. (2013) showed in wheat seedlings that root traits in the laboratory and field correlated positively but that neither correlated with adult root traits in the field. Factors between seedling and adult roots seemed to be differences in developmental stage and the time that growing roots experience the environment.Seedling and adult root differences may be larger in grasses than dicotyledons. Grass root systems have two developmental components: seed-borne (seminal) roots, of which a number emerge at germination and continue to grow and branch throughout the plant life, and stem-borne (nodal or adventitious) roots, which emerge from around the three-leaf stage and continue to emerge, grow, and branch throughout the plant life. Phenotypes and traits of adult root systems of grasses, which include the major cereal crops wheat, rice, and maize, are difficult to predict in seedling screens and ideally identified from adult root systems first (Gamuyao et al., 2012).Phenotyping of adult roots is possible in the field using trenches (Maeght et al., 2013) or coring (Wasson et al., 2014). A portion of the root system is captured with these methods. Alternatively, entire adult root systems can be contained within pots dug into the ground before sowing. These need to be large; field wheat roots, for example, can reach depths greater than 1.5 m depending on genotype and environment. This method prevents root-root interactions that occur under normal field sowing of a plant canopy and is also a compromise.A solution to the problem of phenotyping adult cereal root systems is a model for monocotyledon grasses: Brachypodium distachyon. B. distachyon is a small-stature grass with a small genome that is fully sequenced (Vogel et al., 2010). It has molecular tools equivalent to those available in Arabidopsis (Draper et al., 2001; Brkljacic et al., 2011; Mur et al., 2011). The root system of B. distachyon reference line Bd21 is more similar to wheat than other model and crop grasses (Watt et al., 2009). It has a seed-borne primary seminal root (PSR) that emerges from the embryo at seed germination and multiple stem-borne coleoptile node axile roots (CNRs) and leaf node axile roots (LNRs), also known as crown roots or adventitious roots, that emerge at about three leaves through to grain development. Branch roots emerge from all root types. There are no known anatomical differences between root types of wheat and B. distachyon (Watt et al., 2009). In a recent study, we report postflowering root growth in B. distachyon line Bd21-3, showing that this model can be used to answer questions relevant to the adult root systems of grasses (Chochois et al., 2012).In this study, we used B. distachyon to identify adult plant phenotypes related to the partitioning among seed-borne and stem-borne shoots and roots for the genetic improvement of well-watered and droughted cereals (Fig. 1; Krassovsky, 1926; Navara et al., 1994), nitrogen, phosphorus (Tennant, 1976; Brady et al., 1995), oxygen (Wiengweera and Greenway, 2004), soil hardness (Acuna et al., 2007), and microorganisms (Sivasithamparam et al., 1978). Of note is the study by Krassovsky (1926), which was the first, to our knowledge, to show differences in function related to water. Krassovsky (1926) showed that seminal roots of wheat absorbed almost 2 times the water as nodal roots per unit dry weight but that nodal roots absorbed a more diluted nutrient solution than seminal roots. Krassovsky (1926) also showed by removing seminal or nodal roots as they emerged that “seminal roots serve the main stem, while nodal roots serve the tillers” (Krassovsky, 1926). Volkmar (1997) showed, more recently, in wheat that nodal and seminal roots may sense and respond to drought differently. In millet (Pennisetum glaucum) and sorghum (Sorghum bicolor), Rostamza et al. (2013) found that millet was able to grow nodal roots in a dryer soil than sorghum, possibly because of shoot and root vigor.Open in a separate windowFigure 1.B. distachyon plant scanned at the fourth leaf stage, with the root and shoot phenotypes studied indicated. Supplemental Table S1.
Open in a separate windowThe third reason for dissecting the different root types in this study was that they seem to have independent genetic regulation through major genes. Genes affecting specifically nodal root growth have been identified in maize (Hetz et al., 1996; Hochholdinger and Feix, 1998) and rice (Inukai et al., 2001, 2005; Liu et al., 2005, 2009; Zhao et al., 2009; Coudert et al., 2010; Gamuyao et al., 2012). Here, we also dissect branch (lateral) development on the seminal or nodal roots. Genes specific to branch roots have been identified in Arabidopsis (Casimiro et al., 2003; Péret et al., 2009a), rice (Hao and Ichii, 1999; Wang et al., 2006; Zheng et al., 2013), and maize (Hochholdinger and Feix, 1998; Hochholdinger et al., 2001; Woll et al., 2005).This study explored the hypothesis that adult root systems of B. distachyon contain genotypic variation that can be exploited through phenotyping and genotyping to increase cereal yields. A selection of 79 wild lines of B. distachyon from various parts of the Middle East (Fig. 2 shows the geographic origins of the lines) was phenotyped. They were selected for maximum genotypic diversity from 187 diploid lines analyzed with 43 simple sequence repeat markers (Vogel et al., 2009). We phenotyped shoots and mature root systems concurrently because B. distachyon is small enough to complete its life cycle in relatively small pots of soil with minimal influence of pot size compared with crops, such as wheat. We further phenotyped a subset of this population under irrigation (well watered) and drought to assess genotype response to water supply. By conducting whole-plant studies, we aimed to identify phenotypes that described partitioning among shoot and root components and within seed-borne and stem-borne roots. Phenotypes that have the potential to be beneficial to shoot and root components may speed up genetic gain in future.Open in a separate windowFigure 2.B. distachyon lines phenotyped in this study and their geographical origin. Capital letters in parentheses indicate the country of origin: Turkey (T), Spain (S), and Iraq (I; Vogel et al., 2009). a, Adi3, Adi7, Adi10, Adi12, Adi13, and Adi15; b, Bd21 and Bd21-3 are the reference lines of this study. Bd21 was the first sequenced line (Vogel et al., 2010) and root system (described in detail in Watt et al., 2009), and Bd21-3 is the most easily transformed line (Vogel and Hill, 2008) and parent of a T-DNA mutant population (Bragg et al., 2012); c, Gaz1, Gaz4, and Gaz7; d, Kah1, Kah2, and Kah3. e, Koz1, Koz3, and Koz5; f, Tek1 and Tek6; g, exact GPS coordinates are unknown for lines Men2 (S), Mur2 (S), Bd2.3 (I), Bd3-1 (I), and Abr1 (T). 相似文献
Phenotype | Abbreviation | Unit | Range of Variation | |
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All Experiments (79 Lines and 582 Plants) | Experiment 6 (36 Lines) | |||
Whole plant | ||||
TDW | TDW | Milligrams | 88.6–773.8 (×8.7) | 285.6–438 (×1.5) |
Shoot | ||||
SDW | SDW | Milligrams | 56.4–442.5 (×7.8) | 78.2–442.5 (×5.7) |
No. of tillers | TillerN | Count | 2.8–20.3 (×7.4) | 10–20.3 (×2) |
Total root system | ||||
TRL | TRL | Centimeters | 1,050–10,770 (×10.3) | 2,090–5,140 (×2.5) |
RDW | RDW | Milligrams | 28.9–312.17 (×10.8) | 62.2–179.1 (×2.9) |
Rootpc | Rootpc | Percentage (of TDW) | 20.5–60.6 (×3) | 20.5–44.3 (×2.2) |
R/S | R/S | Unitless ratio | 0.26–1.54 (×6) | 0.26–0.80 (×3.1) |
PSRs | ||||
Length (including branch roots) | PSRL | Centimeters | 549.1–4,024.6 (×7.3) | 716–2,984 (×4.2) |
PSRpc | PSRpc | Percentage (of TRL) | 14.9–94.1 (×6.3) | 31.3–72.3 (×2.3) |
No. of axile roots | PSRcount | Count | 1 | 1 |
Length of axile root | PSRsum | Centimeters | 17.45–52 (×3) | 17.45–30.3 (×1.7) |
Branch roots | PSRbranch | Centimeters · (centimeters of axile root)−1 | 19.9–109.3 (×5.5) | 29.3–104.3 (×3.6) |
CNRs | ||||
Length (including branch roots) | CNRL | Centimeters | 0–3,856.7 | 0–2,266.5 |
CNRpc | CNRpc | Percentage (of TRL) | 0–57.1 | 0–49.8 |
No. of axile roots | CNRcount | Count | 0–2 | 0–2 |
Cumulated length of axile roots | CNRsum | Centimeters | 0–113.9 | 0–47.87 |
Branch roots | CNRbranch | Centimeters · (centimeters of axile root)−1 | 0–77.8 | 0–77.8 |
LNRs | ||||
Length (including branch roots) | LNRL | Centimeters | 99.5–5,806.5 (×58.5) | 216.1–2,532.4 (×11.7) |
LNRpc | LNRpc | Percentage (of TRL) | 4.2–72.7 (×17.5) | 6–64.8 (×10.9) |
LNRcount | LNRcount | Count | 2–22.2 (×11.1) | 3.3–15.3 (×4.6) |
LNRsum | LNRsum | Centimeters | 25.9–485.5 | 48–232 (×4.8) |
Branch roots | LNRbranch | Centimeters · (centimeters of axile root)−1 | 2.1–25.4 (×12.1) | 3.2–15.9 (×5) |
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RAHIL SAID AL-BADI THAMODINI GAYA KARUNASINGHE ABDULLAH MOHAMMED AL-SADI ISSA HASHIL AL-MAHMOOLI RETHINASAMY VELAZHAHAN 《Polish journal of microbiology》2020,69(3):379
Endophytic fungi viz., Nigrospora sphaerica (E1 and E6), Subramaniula cristata (E7), and Polycephalomyces sinensis (E8 and E10) were isolated from the medicinal plant, Shirazi thyme (Zataria multiflora). In in vitro tests, these endophytes inhibited the mycelial growth of Monosporascus cannonballus, a plant pathogenic fungus. Morphological abnormalities in the hyphae of M. cannonballus at the edge of the inhibition zone in dual cultures with N. sphaerica were observed. The culture filtrates of these endophytes caused leakage of electrolytes from the mycelium of M. cannonballus. To our knowledge, this is the first report on the isolation and characterization of fungal endophytes from Z. multiflora as well as their antifungal effect on M. cannonballus.Key words: Zataria multiflora, antifungal, endophytic fungi, Monosporascus cannonballusThe term “Endophytes” denotes microorganisms that colonize plants’ internal tissues for part of or throughout their life cycle without producing any apparent adverse effect. The endophytic microorganisms include fungi, bacteria, and actinobacteria (Bacon and White 2000). Among them, fungi are the most common endophytic microorganisms (Staniek et al. 2008). Endophytic fungi are ecologically distinct polyphyletic groups of microorganisms, mostly belonging to the Ascomycota phylum (Jia et al. 2016). Several fungal endophytes have been shown to act as biological control agents for managing soil-borne plant pathogens (Toghueo et al. 2016).Zataria multiflora Boiss. (Synonyms: Zataria bracteata Boiss.; Zataria multiflora var. elatior Boiss), belonging to the Lamiaceae family is a traditional medicinal plant commonly used as a flavor ingredient in different types of foods (Sajed et al. 2013). Several medicinal properties of Z. multiflora, including antiseptic, anesthetic, antispasmodic, antioxidant, antibacterial, and immunomodulatory activities, have been documented (Sajed et al. 2013). However, studies on the endophytic microorganisms inhabiting Z. multiflora are limited (Mohammadi et al. 2016).Monosporascus cannonballus Pollack & Uecker (Ascomycota, Sordariomycetes, Diatrypaceae) is one of the most important phytopathogenic fungi causing root rot and vine decline disease in muskmelon. It causes sudden wilt and collapse of the plant at the fruiting stage, which may result in total yield loss (Martyn and Miller 1996). The fungus also infects pumpkin, cucumber, courgette, and watermelon plants (Mertely et al. 1993). The control of M. cannonballus in melon and other cucurbit crops is difficult because of the pathogen’s soil-borne nature. Earlier reports indicated that arbuscular mycorrhizal fungi (AMF) (Aleandri et al. 2015), hypovirulent isolates of M. cannonballus (Batten et al. 2000), Trichoderma spp. (Zhang et al. 1999), and antagonistic rhizobacteria (Al-Daghari et al. 2020) are effective agents for the reduction of M. cannonballus-induced root rot and vine decline of melon. In addition, it is well established that many endophytic fungi isolated from medicinal plants possess antimicrobial activity against phytopathogenic fungi (Jia et al. 2016). The objective of this study was to investigate the presence of endophytic fungi in Z. multiflora and to study theirs in vitro antagonistic activity against M. cannonballus.Z. multiflora plants (accession number 201100114) were obtained from Oman Botanic Garden, Al-Khoud, Sultanate of Oman. The plants were healthy, showing no apparent symptoms of any disease or pest infestation. A virulent isolate of M. cannonballus (ID14367), obtained from the roots of a melon plant showing root rot and vine decline (Al-Rawahi et al. 2018) was used in this study. The culture was maintained on potato dextrose agar (PDA) medium (Oxoid Ltd., Basingstoke, UK).To isolate endophytic fungi, Z. multiflora plants were washed in tap water to remove adhering soil particles. The leaves were separated, cut into small pieces, and surface-sterilized by washing in 70% (v/v) ethanol for 1 min and then in 1% (v/v) sodium hypochlorite for 1 min. The plant tissues were then washed 3–4 times with sterilized distilled water. The leaf tissue pieces were further cut into small pieces (0.2–0.5 cm in length) using a sterile scalpel and placed on PDA medium. The plates were incubated at 25 ± 2°C for 7–10 days, and pure cultures of the endophytic fungi were obtained (Lu et al. 2012).DNA was extracted from the mycelia for molecular identification of endophytic fungi according to the method described by Liu et al. (2000). PCR amplification of the Internal Transcribed Spacer (ITS) regions of the fungal rDNA was performed using the primers ITS4 (5’-TCCTCCGCTTATTGATATGC-3’) and ITS5 (5’-GGAAGTAAAAGTCGTAACAAGG-3’) as described by Halo et al. (2018). The PCR products of the expected sizes were sequenced at Macrogen, Seoul, Korea. The sequences were subjected to BLAST searches using the National Center for Biotechnology Information (NCBI) database (http://www.ncbi.nlm.nih.gov).A dual culture technique was used to test the in vitro antagonistic effect of the endophytic fungi against M. cannonballus. A mycelial plug (7-mm diameter) was excised from the fungal endophyte colonies and placed on one side of a PDA plate (90-mm diameter) about 1 cm away from the edge. On the same plate, a 7-mm diameter disc of M. cannonballus was placed on the opposite side at 1 cm distance from the edge. The Petri plates inoculated with M. cannonballus alone were used as control. Four Petri plates per treatment were used. The Petri plates were incubated at 25 ± 2°C, and the radial growth of M. cannonballus was measured after 5–7 days of incubation. The mycelial growth inhibition was calculated using the following formula: where C – radial growth of M. cannonballus in the control plate and T – radial growth of M. cannonballus in the dual culture plate (Toghueo et al. 2016).To investigate the antagonistic effects of the endophytic fungi on the morphology of M. cannonballus hyphae, the five-mm agar plug samples of M. cannonballus were excised from the colony edges of inhibition zone in the dual culture plate. The samples for scanning electron microscopy were prepared according to the method reported by Goldstein et al. (2003) and observed with a JEOL (Model: JSM-7800F) scanning electron microscope. The culture of M. cannonballus grown in the absence of endophytic fungi served as control.To perform the electrolyte leakage assay, the endophytic fungi were cultured in 200 ml of Czapek Dox broth (static) in 500 ml conical flasks at room temperature (25 ± 2°C) for 14 days, and the culture filtrates were obtained by filtering through Whatman No. 1 filter paper. Five hundred mg of M. cannonballus mycelium were added to 20 ml of culture filtrate in a glass vial. The conductivity of the suspension was measured at 0, 1, and 3 h after incubation by using a conductivity meter (Halo et al. 2018). There were three replicates per treatment and control.Data from the in vitro growth inhibition and the electrolyte leakage assays were statistically analyzed using general linear model ANOVA using Minitab Statistical Software version 17 (Minitab Inc., State College, USA). When ANOVA revealed significant differences between treatments, means were separated using Tukey’s studentized range test at p ≤ 0.05. Arc sine transformation of data on % mycelial growth inhibition was done prior to analysis.A total of five morphologically distinct fungal endophytes were obtained from the leaves of Z. multiflora. Based on the rDNA ITS sequence analysis, these endophytic fungal (Ascomycota, Sordariomycetes) isolates were identified as Nigrospora sphaerica (Amphisphaeriales, Apiosporaceae) (E1 and E6), Subramaniula cristata (Sordariales, Chaetomiaceae) (E7) and Polycephalomyces sinensis (Hypocreales, Ophiocordycipitaceae) (E8 and E10). The sequences were deposited in the GenBank database (http://www.ncbi.nlm.nih.gov/genbank/) under the accession numbers , MH028052, MH028054, MH028055, and MH028056. P. sinensis is an important medicinal fungus. Numerous pharmacological activities of P. sinensis including immunomodulatory, anti-estrogenicity and antitumor activities have been documented ( MH028058Wang et al. 2012). N. sphaerica has been reported as an endophyte (Wang et al. 2017) as well as a pathogen in a few plant species (Wright et al. 2008; Liu et al. 2016). However, Z. multiflora plants colonized with these endophytic fungi were healthy and did not show any observable disease symptoms.The in vitro dual culture antagonism assay showed that all the five endophytic fungi inhibited the mycelial growth of M. cannonballus. N. sphaerica E1 was the most effective (81.7%), followed by P. sinensis E8 (80.6%), P. sinensis E10 (75.8%) and N. sphaerica E6 (66.1%). S. cristata E7 was the least effective, which recorded 38.7% inhibition (Table (TableI,I, Fig. Fig.1).1). Further, scanning electron microscopic observations of the hyphae of M. cannonballus from the dual culture assay plates at the edge of the inhibition zone revealed morphological abnormalities such as disintegration, shrinkage, and loss of turgidity. Scanning electron micrograph of M. cannonballus after co-cultivation with the endophytic fungus N. sphaerica E1 is shown in Fig. Fig.2.2. These findings corroborate with those of Hajlaoui et al. (1992) who reported plasmolysis of Sphaerotheca pannosa var. rosae mycelium due to the antagonistic effect of Sporothrix flocculosa. Halo et al. (2018) reported shrinkage of Pythium aphanidermatum hyphae due to the antagonistic activity of Aspergillus terreus. The shrinkage of M. cannonballus hyphae in the present study suggests a possible leakage of cytoplasmic contents (Garg et al. 2010). The loss of the turgidity of M. cannonballus hyphae indicates alterations in the permeability of the cell membrane (Halo et al. 2018). Several reports indicate the production of antimicrobial substances by endophytic fungi (Zhao et al. 2012; Homthong et al. 2016). Kim et al. (2001) demonstrated that phomalactone, a compound produced by N. sphaerica restricted the mycelial growth and germination of sporangium and zoospore of Phytophthora infestans and decreased the incidence of late blight in tomato. Zhao et al. (2012) characterized four secondary antifungal metabolites viz., dechlorogriseofulvin, griseofulvin, mullein, and 8-dihydroramulosin from the liquid cultures of the endophytic fungus Nigrospora sp. isolated from roots of the medicinal plant, Moringa oleifera. Homthong et al. (2016) reported the production of chitinase by Paecilomyces (Polycephalomyces) sp. The inhibitory effect of endophytic fungi on the hyphae of M. cannonballus in this study might be due to the production of antifungal metabolites.Table IPercentage inhibition of mycelial growth of M. cannonballus by endophytic fungi isolated from Zataria multiflora in dual cultures on PDA.
Open in a separate windowData are mean of four replications ± standard deviation. Figures in parentheses are arc sine transformed values. Values in columns followed by different letters indicate significant differences according to the Tukey’s test (p < 0.05).Open in a separate windowFig. 1.In vitro growth inhibition of Monosporascus cannonballus after dual cultivation with several endophytic fungi from Zataria multiflora.a) M. cannonballus (Mc) alone; b) M. cannonballus + N. sphaerica E1; c) M. cannonballus + N. sphaerica E6; d) M. cannonballus + S. cristata E7; e) M. cannonballus + Paecilomyces sinensis E8; f) M. cannonballus + P. sinensis E10Open in a separate windowFig. 2.Scanning electron micrograph showing morphological changes in the hyphae of Monosporascus cannonballus at the edge of the inhibition zone after co-cultivation with Nigrospora sphaerica E1 in PDA platesa) Hyphae of M. cannonballus in the control; b) Hyphae of M. cannonballus after co-cultivation with N. sphaerica E1.Several reports indicate that leakage of electrolytes is an indicator of cell membrane damage in fungi (Manhas and Kaur 2016; Halo et al. 2018). The present study observed that the culture filtrates of endophytic fungi induced electrolyte leakage from the mycelium of M. cannonballus as assessed by increased conductivity of mycelial suspension upon treatment with the culture filtrates of endophytic fungi (Table (TableII).II). The maximum release of electrolytes was observed with N. sphaerica E1, followed by N. sphaerica E6, P. sinensis E10, S. cristata E7, and P. sinensis E8. The results suggest the production of antifungal metabolites as one of the possible mechanisms of action of these fungal endophytes on M. cannonballus.Table IIElectrolyte leakage induced by culture filtrates of endophytic fungi from the mycelium of M. cannonballus.
Open in a separate windowData shown correspond to mean of three replications ± the standard deviation. Values in columns followed by different letters indicate significant differences according to the Tukey’s test (p < 0.05).To our knowledge, this study is the first to report in vitro inhibitory activity of fungal endophytes isolated from Z. multiflora against M. cannonballus. Further studies are needed to evaluate the potential of these fungal endophytes in controlling root rot and vine decline disease of melon, assess their endophytic movement in melon plant, and to determine the mode of action of these fungal endophytes on M. cannonballus. 相似文献
Fungal endophyte | % Inhibition |
---|---|
Nigrospora sphaerica E1 | 81.7 (64.7) ± 5.5a |
Nigrospora sphaerica E6 | 66.1 (54.4) ± 1.9a |
Subramaniula cristata E7 | 38.7 (38.5) ± 3.7b |
Polycephalomyces sinensis E8 | 80.6 (63.9) ± 11.2a |
Polycephalomyces sinensis E10 | 75.8 (60.5) ± 9.3a |
Treatments | Electrical conductivity (mS cm–1) | ||
---|---|---|---|
0 min | 1 h | 3 h | |
Nigrospora sphaerica E1 | 3.95 ± 0.02a | 3.98 ± 0.02a | 4.12 ± 0.06a |
Nigrospora sphaerica E6 | 3.90 ± 0.02b | 3.87 ± 0.02a | 4.01 ± 0.04b |
Subramaniula cristata E7 | 3.46 ± 0.00c | 3.41 ± 0.01c | 3.55 ± 0.01d |
Polycephalomyces sinensis E8 | 3.10 ± 0.03d | 3.28 ± 0.14c | 3.14 ± 0.01e |
Polycephalomyces sinensis E10 | 3.50 ± 0.02c | 3.61 ± 0.00b | 3.71 ± 0.01c |
Czapek Dox broth (un inoculated) | 2.01 ± 0.00e | 2.01 ± 0.00d | 2.08 ± 0.00f |
Control (water) | 0.65 ± 0.01f | 0.67 ± 0.00e | 0.71 ± 0.01g |
9.
Root System Markup Language: Toward a Unified Root Architecture Description Language 总被引:1,自引:0,他引:1
Guillaume Lobet Michael P. Pound Julien Diener Christophe Pradal Xavier Draye Christophe Godin Mathieu Javaux Daniel Leitner Félicien Meunier Philippe Nacry Tony P. Pridmore Andrea Schnepf 《Plant physiology》2015,167(3):617-627
10.
Sabine Drevet Bertrand Favier Emmanuel Brun Gaëtan Gavazzi Bernard Lardy 《Comparative medicine》2022,72(1):3
Osteoarthritis (OA) is a multidimensional health problem and a common chronic disease. It has a substantial impact on patient quality of life and is a common cause of pain and mobility issues in older adults. The functional limitations, lack of curative treatments, and cost to society all demonstrate the need for translational and clinical research. The use of OA models in mice is important for achieving a better understanding of the disease. Models with clinical relevance are needed to achieve 2 main goals: to assess the impact of the OA disease (pain and function) and to study the efficacy of potential treatments. However, few OA models include practical strategies for functional assessment of the mice. OA signs in mice incorporate complex interrelations between pain and dysfunction. The current review provides a comprehensive compilation of mouse models of OA and animal evaluations that include static and dynamic clinical assessment of the mice, merging evaluation of pain and function by using automatic and noninvasive techniques. These new techniques allow simultaneous recording of spontaneous activity from thousands of home cages and also monitor environment conditions. Technologies such as videography and computational approaches can also be used to improve pain assessment in rodents but these new tools must first be validated experimentally. An example of a new tool is the digital ventilated cage, which is an automated home-cage monitor that records spontaneous activity in the cages.Osteoarthritis (OA) is a multidimensional health problem and a common chronic disease.36 Functional limitations, the absence of curative treatments, and the considerable cost to society result in a substantial impact on quality of life.76 Historically, OA has been described as whole joint and whole peri-articular diseases and as a systemic comorbidity.9,111 OA consists of a disruption of articular joint cartilage homeostasis leading to a catabolic pathway characterized by chondrocyte degeneration and destruction of the extracellular matrix (ECM). Low-grade chronic systemic inflammation is also actively involved in the process.42,92 In clinical practice, mechanical pain, often accompanied by a functional decline, is the main reason for consultations. Recommendations to patients provide guidance for OA management.22, 33,49,86 Evidence-based consensus has led to a variety of pharmacologic and nonpharmacologic modalities that are intended to guide health care providers in managing symptomatic patients. Animal-based research is of tremendous importance for the study of early diagnosis and treatment, which are crucial to prevent the disease progression and provide better care to patients.The purpose of animal-based OA research is 2-fold: to assess the impact of the OA disease (pain and function) and to study the efficacy of a potential treatment.18,67 OA model species include large animals such as the horse, goat, sheep, and dog, whose size and anatomy are expected to better reflect human joint conditions. However, small animals such as guinea pig, rabbit, mouse, and rat represent 77% of the species used.1,87 In recent years, mice have become the most commonly used model for studying OA. Mice have several advantageous characteristics: a short development and life span, easy and low-cost breeding and maintenance, easy handling, small joints that allow histologic analysis of the whole joint,32 and the availability of genetically modified lines.108 Standardized housing, genetically defined strains and SPF animals reduce the genetic and interindividual acquired variability. Mice are considered the best vertebrate model in terms of monitoring and controlling environmental conditions.7,14,15,87 Mouse skeletal maturation is reached at 10 wk, which theoretically constitutes the minimal age at which mice should be entered into an OA study.64,87,102 However, many studies violate this limit by testing mice at 8 wk of age.Available models for OA include the following (32,111 physical activity and exercise induced OA; noninvasive mechanical loading (repetitive mild loading and single-impact injury); and surgically induced (meniscectomy models or anterior cruciate ligament transection). The specific model used would be based on the goal of the study.7 For example, OA pathophysiology, OA progression, and OA therapies studies could use spontaneous, genetic, surgical, or noninvasive models. In addition, pain studies could use chemical models. Lastly, post-traumatic studies would use surgical or noninvasive models; the most frequently used method is currently destabilization of the medial meniscus,32 which involves transection of the medial meniscotibial ligament, thereby destabilizing the joint and causing instability-driven OA. An important caveat for mouse models is that the mouse and human knee differ in terms of joint size, joint biomechanics, and histologic characteristics (layers, cellularity),32,64 and joint differences could confound clinical translation.10 Table 1. Mouse models of osteoarthritis.
Open in a separate windowSince all animal models have strengths and weaknesses, it is often best to plan using a number of models and techniques together to combine the results.In humans, the lack of correlation between OA imaging assessment and clinical signs highlights the need to consider the functional data and the quality of life to personalize OA management. Clinical outcomes are needed to achieve 2 main goals: to assess the impact of the OA in terms of pain and function and to study the efficacy of treatments.65 Recent reviews offer few practical approaches to mouse functional assessment and novel approaches to OA models in mice.7,32,67,75,79,83,87, 100,120 This review will focus on static and dynamic clinical assessment of OA using automatic and noninvasive emerging techniques (Test name Techniques Kind of assessment Output Specific equipment required Static measurement Von Frey filament testing Calibrated nylon filaments of various thickness (and applied force) are pressed against the skin of the plantar surface of the paw in ascending order of force Stimulus- evoked pain-like behavior
Mechanical stimuli - Tactile allodynia
The most commonly used test Latency to paw withdrawal
and
Force exerted are recorded Yes Knee extension test Apply a knee extension on both the intact and affected knee
or
Passive extension range of the operated knee joint under anesthesia Stimulus-evoked pain-like behavior Number of vocalizations evoked in 5 extensions None Hotplate Mouse placed on hotplate. A cutoff latency has been determined to avoid lesions Stimulus-evoked pain-like behavior
Heat stimuli- thermal sensitivity Latency of paw withdrawal Yes Righting ability Mouse placed on its back Neuromuscular screening Latency to regain its footing None Cotton swab test Bringing a cotton swab into contact with eyelashes, pinna, and whiskers Stimulus-evoked pain-like behavior
Neuromuscular screening Withdrawal or twitching response None Spontaneous activity Spontaneous cage activity One by one the cages must be laid out in a specific platform Spontaneous pain behavior
Nonstimulus evoked pain
Activity Vibrations evoked by animal movements Yes Open field analysis Experiment is performed in a clear chamber and mice can freely explore Spontaneous pain behavior
Nonstimulus evoked pain
Locomotor analysis Paw print assessment
Distance traveled, average walking speed, rest time, rearing Yes Gait analysis Mouse is placed in a specific cage equipped with a fluorescent tube and a glass plate allowing an automated quantitative gait analysis Nonstimulus evoked pain
Gait analysis
Indirect nociception Intensity of the paw contact area, velocity, stride frequency, length, symmetry, step width Yes Dynamic weight bearing system Mouse placed is a specific cage. This method is a computerized capacitance meter (similar to gait analysis) Nonstimulus evoked pain
Weight-bearing deficits
Indirect nociception Body weight redistribution to a portion of the paw surface Yes Voluntary wheel running Mouse placed is a specific cage with free access to stainless steel activity wheels. The wheel is connected to a computer that automatically record data Nonstimulus evoked pain
Activity Distance traveled in the wheel Yes Burrowing analysis Mouse placed is a specific cage equipped with steel tubes (32 cm in length and 10 cm in diameter) and quartz sand in Plexiglas cages (600 · 340x200 mm) Nonstimulus evoked pain
Activity Amount of sand burrowed Yes Digital video recordings Mouse placed is a specific cage according to the tool Nonstimulus evoked pain
Or
Evoked pain Scale of pain or specific outcome Yes Digital ventilated cage system Nondisrupting capacitive-based technique: records spontaneous activity 24/7, during both light and dark phases directly from the home cage rack Spontaneous pain behavior
Nonstimulus evoked pain
Activity-behavior Distance walked, average speed, occupation front, occupation rear, activation density.
Animal locomotion index, animal tracking distance, animal tracking speed, animal running wheel distance and speed or rotation Yes Challenged activity Rotarod test Gradual and continued acceleration of a rotating rod onto which mice are placed Motor coordination
Indirect nociception Rotarod latency: riding time and speed with a maximum cut off. Yes Hind limb and fore grip strength Mouse placed over a base plate in front of a connected grasping tool Muscle strength of limbs Peak force, time resistance Yes Wire hang analysis Suspension of the mouse on the wire and start the time Muscle strength of limbs: muscle function and coordination Latency to fall gripping None
(self -constructed)
Models | Pros | Cons | |
---|---|---|---|
Spontaneous | Wild type mice7,9,59,67,68,70,72,74,80,85,87,115,118,119,120 | - Model of aging phenotype - The less invasive model - Physiological relevance: mimics human pathogenesis - No need for technical expertise - No need for specific equipment | - Variability in incidence - Large number of animals at baseline - Long-term study: Time consuming (time of onset: 4 -15 mo) - Expensive (husbandry) |
Genetically modified mice2,7,25,40,50,52,67,72,79,80, 89,120 | - High incidence - Earlier time of onset: 18 wk - No need for specific equipment - Combination with other models | - Time consuming for the strain development - Expensive | |
Chemical- induced | Mono-iodoacetate injection7,11,46,47,60,66,90,91,101,128 | - Model of pain-like phenotype - To study mechanism of pain and antalgic drugs - Short-term study: Rapid progression (2-7 wk) - Reproducible - Low cost | - Need for technical expertise - Need for specific equipment - Systemic injection is lethal - Destructive effect: does not allow to study the early phase of pathogenesis |
Papain injection66,67,120 | - Short-term study: rapid progression - Low cost | - Need for technical expertise - Need for specific equipment - Does not mimic natural pathogenesis | |
Collagenase injection7,65,67,98 | - Short-term study: rapid progression (3 wk) - Low cost | - Need for technical expertise - Need for specific equipment - Does not mimic natural pathogenesis | |
Non-invasive | High-fat diet (Alimentary induced obesity model)5,8,43,45,57,96,124 | Model of metabolic phenotype No need for technical expertise No need for specific equipment Reproducible | Long-term study: Time consuming (8 wk–9 mo delay) Expensive |
Physical activity and exercise model45,73 | Model of post traumatic phenotype No need for technical expertise | Long-term study: time consuming (18 mo delay) Expensive Disparity of results | |
Mechanical loading models Repetitive mild loading models Single-impact injury model7,16,23,24, 32,35,104,105,106 | Model of post traumatic phenotype Allow to study OA development Time of onset: 8-10 wk post injury Noninvasive | Need for technical expertise Need for specific equipment Heterogeneity in protocol practices Repetitive anesthesia required or ethical issues | |
Surgical | Ovariectomy114 | Contested. | |
Meniscectomy model7,32,63,67,87 | Model of post traumatic phenotype High incidence Short-term study: early time of onset (4 wk from surgery) To study therapies | Need for technical expertise Need for specific equipment Surgical risks Rapid progression compared to human | |
Anterior cruciate ligament transection (ACLT)7,39,40,61,48,67,70,87,126 | Model of posttraumatic phenotype High incidence Short-term study: early time of onset (3-10 wk from surgery) Reproducible To study therapies | Need for technical expertise Need for specific equipment Surgical risks Rapid progression compared to human | |
Destabilization of medial meniscus (DMM)7,32,39,40 | Model of post traumatic phenotype High incidence Short-term study: early time of onset (4 wk from surgery) To study therapies The most frequently used method | Need for technical expertise Need for specific equipment Surgical risks Rapid progression compared to human |
Mechanical stimuli - Tactile allodynia
The most commonly used test
and
Force exerted are recorded
or
Passive extension range of the operated knee joint under anesthesia
Heat stimuli- thermal sensitivity
Neuromuscular screening
Nonstimulus evoked pain
Activity
Nonstimulus evoked pain
Locomotor analysis
Distance traveled, average walking speed, rest time, rearing
Gait analysis
Indirect nociception
Weight-bearing deficits
Indirect nociception
Activity
Activity
Or
Evoked pain
Nonstimulus evoked pain
Activity-behavior
Animal locomotion index, animal tracking distance, animal tracking speed, animal running wheel distance and speed or rotation
Indirect nociception
(self -constructed)