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Plant Disease Feb 2024The dragon fruit is native of Mexico, and Puebla is the third-largest producing state (SIAP 2023). In June 2023, field sampling was conducted in El Paraíso, Atlixco...
The dragon fruit is native of Mexico, and Puebla is the third-largest producing state (SIAP 2023). In June 2023, field sampling was conducted in El Paraíso, Atlixco (18° 49' 5.275" N, 98° 26' 52.353" W), Puebla, Mexico. The mean temperature and relative humidity were 20 °C and 75% for seven consecutive days. Dragon fruits cv. 'Delight' close to harvest with gray mold symptoms were found in a commercial area of 2 ha, with an incidence of 35 to 40% and an estimated severity of 75% on infected fruit. The symptoms included necrosis at the apex, which later spread throughout the fruit, along with a soft, black rot covered in abundant mycelium and sporulation. The fungus was isolated from 40 symptomatic fruits by disinfesting pieces of necrotic tissue with 3% NaClO for one minute, rinsing with sterile distilled water (SDW), plating on Petri dishes with potato dextrose agar, and incubating at 25 °C in the dark. One isolate was obtained from each diseased fruit by the hyphal-tip method. The colonies were initially white with a growth rate of 1.15-1.32 cm per day and turned gray after 10 days; the mycelium was dense and aerial. Spherical and irregular sclerotia were formed, measuring 0.9-1.4 × 0.6-1.1 mm (n = 100). Each Petri dish produced 56-278 sclerotia (n = 40) after 11 days; these were initially white and gradually turned dark brown. Brown to olive conidiophores were straight, septate, and branched, measuring 1075-1520 × 10-21 μm, with elliptical hyaline to light brown conidia of 6.6-11.5 × 5-8.1 μm (n=100). The isolates were tentatively identified as based on morphological characteristics (Ellis 1971). Two representative isolates were chosen for molecular identification and genomic DNA was extracted by the CTAB protocol. The ITS region and the heat shock protein (HSP60), RNA polymerase binding II (RPB2) and glyceraldehyde 3-phosphate dehydrogenase (G3PDH) genes were sequenced (White et al. 1990; Staats et al. 2005). The sequences of a representative isolate (BcPh5) were deposited in GenBank (ITS-OR582337; HSP60-OR636622; RPB2-OR636623; and G3PDH-OR636621). BLAST analysis of the partial sequences of ITS (479 bp), HSP60 (1006 bp), RPB2 (1126 bp), and G3PDH (907 bp) showed 100% similarity to . isolates (GenBank: KM840848, MH796663, MK919495, MF480679). Phylogenetic analysis confirmed that BcPh5 clustered with . strains. Pathogenicity was confirmed by inoculating the non-wounded surface of 20 detached dragon fruits cv. 'Delight' using the BcPh5 isolate by depositing 20 μl of a 10 conidia/ml suspension with a sterile syringe. The fruits were placed on the rim of a plastic container and inserted in a moisture box with 2 cm of water at the bottom. The box was covered with a plastic sheet to maintain humidity. Control fruits were inoculated with SDW. The inoculated fruits became covered with abundant white to gray mycelium, and soft rot developed within eight days, while no symptoms were observed on the controls. The fungus was re-isolated from the inoculated fruits as described above, fulfilling Koch's postulates. The pathogenicity tests were repeated three times. Gray mold caused by . was also recently reported in Mexico on pomegranate (Hernández et al. 2023) and rose apple (Isodoro et al. 2023). As far as we know, this is the first report of . causing gray mold on dragon fruit in Mexico. This research is essential for designing integrated management strategies against gray mold on dragon fruits.
PubMed: 38422435
DOI: 10.1094/PDIS-11-23-2348-PDN -
Biosensors & Bioelectronics Apr 2024The rapid identification of pathogenic bacteria is crucial across various industries, including food or beverage manufacturing. Bacterial microcolony image-based...
The rapid identification of pathogenic bacteria is crucial across various industries, including food or beverage manufacturing. Bacterial microcolony image-based classification has emerged as a promising approach to expedite identification, automate inspections, and reduce costs. However, conventional imaging methods have significant practical limitations, namely low throughput caused by the limited imaging range and slow imaging speed. To address these challenges, we developed an imaging system based on a line image sensor for rapid and wide-field imaging compared to existing colony imaging methods. This system can image a standard Petri dish (92 mm in diameter) completely within 22 s, successfully acquiring bacterial microcolony images. This process yielded a set of discrimination parameters termed as colony fingerprints, which were employed for machine learning. We demonstrated the performance of our system by identifying Staphylococcus aureus in food products using a machine learning model trained on a colony fingerprint dataset of 15 species from 9 genera, including foodborne pathogens. While conventional mass spectrometry-based methods require 24 h of incubation, our colony fingerprinting approach achieved 96% accuracy in just 10 h of incubation. Line image sensor offer high imaging speeds and scalability, allowing for swift and straightforward microbiological testing, eliminating the need for specialized expertise and overcoming the limitations of conventional methods. This innovation marks a transformative shift in industrial applications.
Topics: Biosensing Techniques; Bacteria; Machine Learning
PubMed: 38199081
DOI: 10.1016/j.bios.2024.116006 -
Integrative and Comparative Biology Dec 2023In the context of climate warming, the intensity and frequency of drought occurrences are progressively increasing. However, current research on the impacts of drought...
In the context of climate warming, the intensity and frequency of drought occurrences are progressively increasing. However, current research on the impacts of drought on the life history traits and physiological activities of animals rarely encompass soil animals that play crucial roles within soil ecosystems. Therefore, this study focused on a soil nematode species (Acrobeloides sp.) and a model nematode (Caenorhabditis elegans) to investigate whether nematodes adjust the trade-off of their life history traits to confront arid environments, utilizing a Petri dish experiment. Subsequently, we assessed the resilience of the two nematode species to moisture variations by comparing the extent of changes in various indicators (i.e., life history traits, physiological trait, and oxidative stress) of nematodes before and after drought and rehydration. The results revealed that both nematode species are capable of adapting to arid environments by altering the trade-off between life-history traits. Specifically, they reduce reproductive investment and bodymass while maintaining lifespan, thus responding to drought conditions. Follow-up rehydration experiments post-drought stress highlighted that soil-dwelling nematode exhibit a superior recovery capacity in response to moisture fluctuations in comparison to the model nematode. To the best of our knowledge, this is the first investigation into life history of drought adaptation within soil-dwelling nematode. Moreover, the findings hold significant implications for the exploration of drought adaptation and its mechanisms in soil-dwelling animals.
PubMed: 38070876
DOI: 10.1093/icb/icad129 -
Pest Management Science Mar 2024The biocontrol potential of soil microbes can reduce the extensive use of hazardous synthetic fungicides. This study was designed to find a strain of rhizobacteria...
BACKGROUND
The biocontrol potential of soil microbes can reduce the extensive use of hazardous synthetic fungicides. This study was designed to find a strain of rhizobacteria indigenous to Pakistan with potential biocontrol against early blight of tomato caused by Alternaria solani and to characterize its biocontrol mechanisms.
RESULTS
Among 88 strains tested for antagonism against A. solani on agar media, S27, Dt10 and 423, identified by 16S rRNA sequencing as strains of Bacillus amyloliquefaciens, B. cereus and Stenotrophomonas rhizophila, respectively, were the most inhibitory. When applied to detached tomato leaflets in Petri dish assays, the strains reduced lesion development by over 30% compared to the control. In greenhouse pot trials, the bacterial strains reduced early blight severity by over 50%. In three field trials, all three strains applied to tomato foliage slowed early blight disease progress and reduced disease severity, with B. amyloliquefaciens S27 reducing the area under the disease progress curve by up to 70%. All three strains showed protease, catalase and oxidase activities in vitro, but none produced β-1,3-glucanase and only B. cereus Dt10 showed slight chitinase activity. In a greenhouse experiment in which the bacteria were applied to tomato foliage prior to pathogen inoculation, bacteria-treated leaves had higher β-1,3-glucanase and chitinase levels than leaves inoculated only with the pathogen, indicating priming induction of response.
CONCLUSION
Three rhizobacteria strains have the potential to control early blight of tomato under Pakistan's growing conditions, with B. amyloliquefaciens S27 being the most promising candidate for commercial development. Antagonism and induction of the priming response may be mechanisms of biocontrol by the bacterial strains. © 2023 Society of Chemical Industry.
Topics: Solanum lycopersicum; Pakistan; RNA, Ribosomal, 16S; Chitinases; Plant Diseases
PubMed: 37939120
DOI: 10.1002/ps.7872 -
PloS One 2024In Tunisia, Orobanche foetida Poir. is considered an important agricultural biotic constraint on faba bean (Vicia faba L.) production. An innovative control method for...
In Tunisia, Orobanche foetida Poir. is considered an important agricultural biotic constraint on faba bean (Vicia faba L.) production. An innovative control method for managing this weed in faba bean is induced resistance through inoculation by rhizobia strains. In this study, we explored the biochemical dynamics in V. faba L. minor inoculated by rhizobia in response to O. foetida parasitism. A systemic induced resistant reaction was evaluated through an assay of peroxidase (POX), polyphenol oxidase (PPO) and phenyl alanine ammonialyase (PAL) activity and phenolic compound and hydrogen peroxide (H2O2) accumulation in faba bean plants infested with O. foetida and inoculated with rhizobia. Two rhizobia strains (Mat, Bj1) and a susceptible variety of cultivar Badi were used in a co-culture Petri dish experiment. We found that Mat inoculation significantly decreased O. foetida germination and the number of tubercles on the faba bean roots by 87% and 88%, respectively. Following Bj1 inoculation, significant decreases were only observed in O. foetida germination (62%). In addition, Mat and Bj1 inoculation induced a delay in tubercle formation (two weeks) and necrosis in the attached tubercles (12.50% and 4.16%, respectively) compared to the infested control. The resistance of V. faba to O. foetida following Mat strain inoculation was mainly associated with a relatively more efficient enzymatic antioxidative response. The antioxidant enzyme activity was enhanced following Mat inoculation of the infected faba bean plant. Indeed, increases of 45%, 67% and 86% were recorded in the POX, PPO and PAL activity, respectively. Improvements of 56% and 12% were also observed in the soluble phenolic and H2O2 contents. Regarding inoculation with the Bj1 strain, significant increases were only observed in soluble phenolic and H2O2 contents and PPO activity (especially at 45 days after inoculation) compared to the infested control. These results imply that inoculation with the rhizobia strains (especially Mat) induced resistance and could bio-protect V. faba against O. foetida parasitism by inducing systemic resistance, although complete protectionwas not achieved by rhizobia inoculation. The Mat strain could be used as a potential candidate for the development of an integrated method for controlling O. foetida parasitism in faba bean.
Topics: Orobanche; Vicia faba; Hydrogen Peroxide; Catechol Oxidase; Plant Roots; Rhizobium; Peroxidase; Plant Diseases; Phenylalanine Ammonia-Lyase
PubMed: 38820398
DOI: 10.1371/journal.pone.0304673 -
The Science of the Total Environment Aug 2024Bees are important pollinators for ecosystems and agriculture; however, populations have suffered a decline that may be associated with several factors, including...
Bees are important pollinators for ecosystems and agriculture; however, populations have suffered a decline that may be associated with several factors, including habitat loss, climate change, increased vulnerability to diseases and parasites and use of pesticides. The extensive use of neonicotinoids, including imidacloprid, as agricultural pesticides, leads to their persistence in the environment and accumulation in bees, pollen, nectar, and honey, thereby inducing deleterious effects. Forager honey bees face significant exposure to pesticide residues while searching for resources outside the hive, particularly systemic pesticides like imidacloprid. In this study, 360 Apis mellifera bees, twenty-one days old (supposed to be in the forager phase) previously marked were fed syrup (honey and water, 1:1 m/v) containing a lethal dose (0.081 μg/bee) or sublethal dose (0.00081 μg/bee) of imidacloprid. The syrup was provided in plastic troughs, with 250 μL added per trough onto each plastic Petri dish containing 5 bees (50 μL per bee). The bees were kept in the plastic Petri dishes inside an incubator, and after 1 and 4 h of ingestion, the bees were euthanised and stored in an ultra-freezer (-80 °C) for transcriptome analysis. Following the 1-h ingestion of imidacloprid, 1516 genes (73 from lethal dose; 1509 from sublethal dose) showed differential expression compared to the control, while after 4 h, 758 genes (733 from lethal dose; 25 from sublethal) exhibited differential expression compared to the control. All differentially expressed genes found in the brain tissue transcripts of forager bees were categorised based on gene ontology into functional groups encompassing biological processes, molecular functions, and cellular components. These analyses revealed that sublethal doses might be capable of altering more genes than lethal doses, potentially associated with a phenomenon known as insecticide-induced hormesis. Alterations in genes related to areas such as the immune system, nutritional metabolism, detoxification system, circadian rhythm, odour detection, foraging activity, and memory in bees were present after exposure to the pesticide. These findings underscore the detrimental effects of both lethal and sublethal doses of imidacloprid, thereby providing valuable insights for establishing public policies regarding the use of neonicotinoids, which are directly implicated in the compromised health of Apis mellifera bees.
Topics: Animals; Bees; Neonicotinoids; Nitro Compounds; Insecticides; Gene Expression
PubMed: 38795984
DOI: 10.1016/j.scitotenv.2024.173393 -
Microorganisms Jun 2024Edible fungi are a valuable resource in the search for sustainable solutions to environmental pollution. Their ability to degrade organic pollutants, extract heavy...
Edible fungi are a valuable resource in the search for sustainable solutions to environmental pollution. Their ability to degrade organic pollutants, extract heavy metals, and restore ecological balance has a huge potential for bioremediation. They are also sustainable food resources. Edible fungi (basidiomycetes or fungi from other divisions) represent an underutilized resource in the field of bioremediation. By maximizing their unique capabilities, it is possible to develop innovative approaches for addressing environmental contamination. The aim of the present study was to find selective chemical agents suppressing the growth of microfungi and bacteria, but not suppressing white-rot fungi, in order to perform large-scale cultivation of white-rot fungi in natural unsterile substrates and use it for different purposes. One application could be the preparation of a matrix composed of wooden sleeper (contaminated with PAHs) and soil for further hazardous waste bioremediation using white-rot fungi. In vitro microbiological methods were applied, such as, firstly, compatibility tests between bacteria and white-rot fungi or microfungi, allowing us to evaluate the interaction between different organisms, and secondly, the addition of chemicals on the surface of a Petri dish with a test strain of microorganisms of white-rot fungi, allowing us to determine the impact of chemicals on the growth of organisms. This study shows that white-rot fungi are not compatible to grow with several rhizobacteria or bacteria isolated from soil and bioremediated waste. Therefore, the impact of several inorganic materials, such as lime (hydrated form), charcoal, dolomite powder, ash, gypsum, phosphogypsum, hydrogen peroxide, potassium permanganate, and sodium hydroxide, was evaluated on the growth of microfungi (sixteen strains), white-rot fungi (three strains), and bacteria (nine strains) . Charcoal, dolomite powder, gypsum, and phosphogypsum did not suppress the growth either of microfungi or of bacteria in the tested substrate, and even acted as promoters of their growth. The effects of the other agents tested were strain dependent. Potassium permanganate could be used for bacteria and spp. growth suppression, but not for other microfungi. Lime showed promising results by suppressing the growth of microfungi and bacteria, but it also suppressed the growth of white-rot fungi. Hydrogen peroxide showed strong suppression of microfungi, and even had a bactericidal effect on some bacteria, but did not have an impact on white-rot fungi. The study highlights the practical utility of using hydrogen peroxide up to 3% as an effective biota-suppressing chemical agent prior to inoculating white-rot fungi in the large-scale bioremediation of polluted substrates, or in the large-scale cultivation for mushroom production as a foodstuff.
PubMed: 38930624
DOI: 10.3390/microorganisms12061242 -
Insects Feb 2024Human lice are the only hematophagous ectoparasites specific to human hosts. They transmit epidemic typhus, trench fever and relapsing fever, diseases which have already...
Human lice are the only hematophagous ectoparasites specific to human hosts. They transmit epidemic typhus, trench fever and relapsing fever, diseases which have already caused millions of deaths worldwide. In order to further investigate lice vectorial capacities, laboratory-controlled live lice colonies are essential. Previously developed lice-rearing methods significantly advanced research on louse-borne diseases and louse biology. In this study, we aimed to develop a rearing technique for the Orlando (Or) strain of body lice on an artificial membrane. We tested two systems, namely the Hemotek feeding system and a Petri dish with the lice being fed through a Parafilm membrane. Lice longevity and development were drastically affected by the blood anticoagulant. Additionally, heparinised human blood on a Petri dish was the best candidate when compared to the control group (reared on a rabbit). Therefore, this strategy was applied to 500 lice. Development into adulthood was recorded after 21 days (17 days for the rabbits), and 52 eggs were deposited (240 for the rabbits). In this study, we were able to maintain one generation of body lice on an artificial membrane with comparable feeding and longevity rates to those fed on live rabbits. However, lice fecundity decreased on the artificial membrane. In vitro lice-rearing experiments will enable pathogen infection assays and pesticide bioassays to be carried out in accordance with animal welfare requirements.
PubMed: 38535341
DOI: 10.3390/insects15030145 -
Plant Disease Jan 2024Gastrodia elata Blume is a valuable medicinal plant in China with great significance in medicine (Li et al. 2023). From 2022 to 2023, G. elata tuber rot occurred in...
Gastrodia elata Blume is a valuable medicinal plant in China with great significance in medicine (Li et al. 2023). From 2022 to 2023, G. elata tuber rot occurred in about 50 households in the main cultivation areas of G. elata (27°39' N, 104°16' E) in Yiliang County, Zhaotong, Yunnan Province, southwest China. The planting area of G. elata was 776 ha, and the incidence rate was 10%. Symptoms present as light brown lesions on the surface of the tuber, sunken, soft and foul-smelling. Infected G. elata tubers were randomly collected from each household, packed into transparent plastic bags, and strains were isolated in the laboratory as follows. The tubers of 15 infected G. elata tubers were surface-sterilized with 0.5% NaOCl for 2 min, rinsed five times with sterile water, and dried. Symptomatic tissues from the margin between necrotic and healthy tissues were cut into 5 × 5 mm pieces, placed onto potato dextrose agar (PDA), and incubated at 28 ºC in the dark for 3 days. Hyphal tips of fungi growing from the samples were transferred onto new PDA plates and incubated until they produced conidia. Two fungal strains (Charliezhao 425 and 433) with the same morphological characteristics were obtained from the samples. Colonies were whitish and grew rapidly, irregularly turning pale orange at the edge or center of the mycelium pad on a two-week-old petri dish, and finally dark red,spore oval to spherical, 2.7 to 5.3 × 2.3 to 3.5 μm (n=50). The morphological characteristics of the isolates resembled Porogramme epimiltina (Mao et al. 2023; Kubayashi et al. 2001). Genomic DNA of two representative isolates (Charliezhao 425 and 433) was extracted using the DN14 cetyltrimethylammonium bromide rapid plant genome extraction kit (Aidlab Biotechnologies Co., Ltd, Beijing). The ITS and TEF1 genes were amplified by polymerase chain reaction using the primers ITS1/ITS4 (White et al. 1990) and EF1-983F/EF1-2218R (Rehner et al, 2005), respectively. All sequences were deposited in GenBank (accession no. OR905803, OR905804 for ITS, OR939812, OR939813 for TEF1). A BLASTN homology search with the ITS nucleotide sequences showed that they had 98.99 to 99.15% identity with P. epimiltina isolate OP997539 (588/594 bp) and isolate OP997539 (584/589 bp), respectively; and the TEF1 sequences had 95.41 to 95.59% % identity to isolates OP556566 (540/565 bp) and isolate OP556566 (542/567 bp), respectively. To complete Koch's hypothesis, the surfaces of 5 mature and healthy G. elata tubers were disinfected with 1% NaClO solution for 1 minute, rinsed with sterile water 5 times, and dried at 25 ℃ for 30 minutes. Conidial suspensions (106 spores/ml) were collected from two isolates (Charliezhao 425 and 433) and sprayed on G. elata tuber, and the control treated with distilled water. All G. elata tubers were incubated at 25℃ with 80% relative humidity. The experiment had three replicates. After 7 days of culture, there were obvious rotten and smelly on the inoculated tubers. No symptoms were observed in the control groups. The pathogen was re-isolated from all inoculated birch tubers and confirmed as P. epimiltina by morphological and molecular analysis, which fulfilled Koch's hypothesis. Gastrodia elata is a valuable and extensively used herbal Traditional Chinese Medicine with a wide range of clinical applications. As far as we know, this is the first report of P. epimiltina causing brown rot of G. elata in China.
PubMed: 38268169
DOI: 10.1094/PDIS-12-23-2733-PDN -
Lab on a Chip Aug 2023The function of vascular endothelial cells (ECs) within the complex vascular microenvironment is typically modulated by biochemical cues, cell-cell interactions, and...
The function of vascular endothelial cells (ECs) within the complex vascular microenvironment is typically modulated by biochemical cues, cell-cell interactions, and fluid shear stress. These regulatory factors play a crucial role in determining cell mechanical properties, such as elastic and shear moduli, which are important parameters for assessing cell status. However, most studies on the measurement of cell mechanical properties have been conducted , which is labor-intensive and time-consuming. Notably, many physiological factors are lacking in Petri dish culture compared with conditions, leading to inaccurate results and poor clinical relevance. Herein, we developed a multi-layer microfluidic chip that integrates dynamic cell culture, manipulation and dielectrophoretic measurement of mechanical properties. Furthermore, we numerically and experimentally simulated the vascular microenvironment to investigate the effects of flow rate and tumor necrosis factor-alpha (TNF-α) on the Young's modulus of human umbilical vein endothelial cells (HUVECs). Results showed that greater fluid shear stress results in increased Young's modulus of HUVECs, suggesting the importance of hemodynamics in modulating the biomechanics of ECs. In contrast, TNF-α, an inflammation inducer, dramatically decreased HUVEC stiffness, demonstrating an adverse impact on the vascular endothelium. Blebbistatin, a cytoskeleton disruptor, significantly reduced the Young's modulus of HUVECs. In summary, the proposed vascular-mimetic dynamic culture and monitoring approach enables the physiological development of ECs in organ-on-a-chip microsystems for accurately and efficiently studying hemodynamics and pharmacological mechanisms underlying cardiovascular diseases.
Topics: Humans; Microfluidics; Tumor Necrosis Factor-alpha; Cell Culture Techniques; Human Umbilical Vein Endothelial Cells; Cytoskeleton; Stress, Mechanical
PubMed: 37417786
DOI: 10.1039/d3lc00363a