-
Plant Disease Apr 2024In April 2023, soft rot symptoms were observed in broccoli (Brassica oleracea L. var. italica) commercial fields in Songming County, Yunnan province, China (103°12'E,...
In April 2023, soft rot symptoms were observed in broccoli (Brassica oleracea L. var. italica) commercial fields in Songming County, Yunnan province, China (103°12'E, 25°31'N). The disease incidence in these fields (6 ha in size) was high, exceeding 50%, and it caused significant yield loss. The affected plants displayed characteristic symptoms, with the roots and stems of broccoli becoming soft, yellowish-brown, rotten, and emitting a foul odor. To identify the causal agent, soft rot symptomatic stems were surface sterilized by dipping them in 75% ethanol for 30 seconds, followed by three successive rinses with sterile distilled water. Tissue specimens were then plated onto nutrient agar (NA) plates and incubated at 28°C for 24 hours. (Wang et al. 2022). Three representative bacterial isolates HYC22041801-HYC22041803 from broccoli were selected for further analysis. The colonies on NA plates appeared as white, small, round, and translucent with smooth edges. Physiological and biochemical tests were performed, along with 96 phenotypic screenings using the BIOLOG GENIII microplate system (Biolog, Hayward, CA, USA). Three isolates were negative for D-arabitol, maltose, and sorbitol, but were positive for cellobiose, α-D-glucose, sucrose, glycerol and gentiobiose tests, which are consistent with the reported type strain P. polaris NIBIO1006T (Chen et al. 2021). Total genomic DNA was extracted from three bacterial isolates using the QIAamp DNA Mini Kit (QIAGEN, USA). The 16S rRNA region and nine housekeeping genes (gapA, icdA, mdh, mtlD, pel, pgi, pmrA, proA and rpoS) were amplified with universal primers 27F/1492R (Monciardini et al., 2006) and designed specific primers (Xie et al., 2018), respectively. All amplicons were sequenced and deposited in GenBank with accession numbers ON723841-ON723843 and ON723846-ON723872. The BLASTn analysis of the 16S rRNA amplicons confirmed that the isolates HYC22041801-HYC22041803 belonged to the genus Pectobacterium. Phylogenetic trees based on 16S rRNA gene sequences and multilocus sequence analysis of other nine housekeeping genes of the three isolates were constructed and the results revealed that three isolates clustered with P. polaris type strain NIBIO1006T, which was previously isolated from potato (Dees et al., 2017). To confirm the pathogenicity, nine broccoli seedlings were stab inoculated with a bacterial suspension (108 CFU·ml-1), while sterile distilled liquid LB medium was used as a negative control. The seedlings were kept at 80% relative humidity and 28°C in a growth chamber. Three trials were conducted per isolate (HYC22041801-HYC22041803). After 3 days, the inoculated petioles showed soft rot symptoms similar to those observed initially in the field, while control plants remained asymptomatic. All three isolates were re-isolated successfully from symptomatic tissues to complete Koch's postulates. P. polaris has been previously reported as the causative agent of blackleg in potato in several countries, including Norway, Poland, Russia, and China (Handique et al. 2022; Wang et al. 2022). Additionally, it was reported to cause soft rot in Chinese cabbage in China (Chen et al. 2021). However, this is the first report of P. polaris causing soft rot disease in broccoli in China. This discovery is of great importance for vegetable growers because this bacterium is well established on Cruciferous vegetables in the local area, and effective measures are needed to manage this disease.
PubMed: 38687572
DOI: 10.1094/PDIS-08-23-1475-PDN -
Nature Communications Apr 2024Controlled assembly of a protein shell around a viral genome is a key step in the life cycle of many viruses. Here we report a strategy for regulating the co-assembly of...
Controlled assembly of a protein shell around a viral genome is a key step in the life cycle of many viruses. Here we report a strategy for regulating the co-assembly of nonviral proteins and nucleic acids into highly ordered nucleocapsids in vitro. By fusing maltose binding protein to the subunits of NC-4, an engineered protein cage that encapsulates its own encoding mRNA, we successfully blocked spontaneous capsid assembly, allowing isolation of the individual monomers in soluble form. To initiate RNA-templated nucleocapsid formation, the steric block can be simply removed by selective proteolysis. Analyses by transmission and cryo-electron microscopy confirmed that the resulting assemblies are structurally identical to their RNA-containing counterparts produced in vivo. Enzymatically triggered cage formation broadens the range of RNA molecules that can be encapsulated by NC-4, provides unique opportunities to study the co-assembly of capsid and cargo, and could be useful for studying other nonviral and viral assemblies.
Topics: Nucleocapsid; Cryoelectron Microscopy; Maltose-Binding Proteins; Virus Assembly; Capsid; RNA, Viral; Capsid Proteins; RNA, Messenger
PubMed: 38678040
DOI: 10.1038/s41467-024-47808-1 -
Microorganisms Apr 2024was primarily identified based on the characteristics of its conidia and several sequences. The fungus causes severe leaf spot disease on hairy vetch ( var. ) in Yunnan...
was primarily identified based on the characteristics of its conidia and several sequences. The fungus causes severe leaf spot disease on hairy vetch ( var. ) in Yunnan Province in China. The growth, sporulation, fungicide efficacy, and host range of the pathogen were evaluated to aid in disease management. Different types of culture media and carbon and nitrogen sources were used to evaluate the growth of Oatmeal, maltose, and potassium nitrate agar had a higher amount of sporulation. Difenoconazole (10%) was the most effective fungicide against the leaf disease caused by . In addition, foliar inoculation sprays were used to assess the host range of in six different plant species, including alfalfa ( L.), sainfoin ( Scop.), erect milkvetch ( Pall.), common vetch ( L.), red clover ( L.), and white clover ( L.). successfully infected these plants, indicating that it has a wider host range than hairy vetches.
PubMed: 38674710
DOI: 10.3390/microorganisms12040766 -
International Journal of Molecular... Apr 2024Membrane proteins constitute about 20% of the human proteome and play crucial roles in cellular functions. However, a complete understanding of their structure and...
Membrane proteins constitute about 20% of the human proteome and play crucial roles in cellular functions. However, a complete understanding of their structure and function is limited by their hydrophobic nature, which poses significant challenges in purification and stabilization. Detergents, essential in the isolation process, risk destabilizing or altering the proteins' native conformations, thus affecting stability and functionality. This study leverages single-particle cryo-electron microscopy to elucidate the structural nuances of membrane proteins, focusing on the SLAC1 bacterial homolog from (TehA) purified with diverse detergents, including n-dodecyl β-D-maltopyranoside (DDM), glycodiosgenin (GDN), β-D-octyl-glucoside (OG), and lauryl maltose neopentyl glycol (LMNG). This research not only contributes to the understanding of membrane protein structures but also addresses detergent effects on protein purification. By showcasing that the overall structural integrity of the channel is preserved, our study underscores the intricate interplay between proteins and detergents, offering insightful implications for drug design and membrane biology.
Topics: Cryoelectron Microscopy; Haemophilus influenzae; Bacterial Proteins; Detergents; Microscopy, Electron, Transmission; Membrane Proteins
PubMed: 38674110
DOI: 10.3390/ijms25084528 -
Pathogens (Basel, Switzerland) Apr 2024A novel coagulase-negative strain (H164) was isolated from soymilk in Taiwan. Comparative sequence analysis of the 16S rRNA gene revealed that the H164 strain is a...
A novel coagulase-negative strain (H164) was isolated from soymilk in Taiwan. Comparative sequence analysis of the 16S rRNA gene revealed that the H164 strain is a member of the genus . We used multilocus sequence analysis (MLSA) and phylogenomic analyses to demonstrate that the novel strain was closely related to , , , and . The average nucleotide identity and digital DNA-DNA hybridization values between H164 and its closest relatives were <95% and <70%, respectively. The H164 strain could also be distinguished from its closest relatives by the fermentation of -fructose, -maltose, -trehalose, and -mannitol, as well as by the activities of α-glucosidase and alkaline phosphatase. The major cellular fatty acids were C15:0 iso and C15:0 anteiso, and the predominant menaquinones were MK-7 and MK-8, respectively. The major cellular fatty acids and predominant menaquinones were C iso and C anteiso and MK-7 and MK-8, respectively. In conclusion, this strain represents a novel species, named sp. nov., with the type strain H164 (=BCRC 81404 = NBRC 116174).
PubMed: 38668298
DOI: 10.3390/pathogens13040343 -
Journal of Fungi (Basel, Switzerland) Mar 2024Sialidases (neuraminidases) catalyze the removal of terminal sialic acid residues from glycoproteins. Novel enzymes from non-clinical isolates are of increasing interest...
Sialidases (neuraminidases) catalyze the removal of terminal sialic acid residues from glycoproteins. Novel enzymes from non-clinical isolates are of increasing interest regarding their application in the food and pharmaceutical industry. The present study aimed to evaluate the participation of carbon catabolite repression (CCR) in the regulation of cold-active sialidase biosynthesis by the psychrotolerant fungal strain P29, isolated from Antarctica. The presence of glucose inhibited sialidase activity in growing and non-growing fungal mycelia in a dose- and time-dependent manner. The same response was demonstrated with maltose and sucrose. The replacement of glucose with glucose-6-phosphate also exerted CCR. The addition of cAMP resulted in the partial de-repression of sialidase synthesis. The CCR in the psychrotolerant strain P29 did not depend on temperature. Sialidase might be subject to glucose repression by both at 10 and 25 °C. The fluorescent assay using 4MU-Neu5Ac for enzyme activity determination under increasing glucose concentrations evidenced that CCR may have a regulatory role in sialidase production. The real-time RT-PCR experiments revealed that the sialidase gene was subject to glucose repression. To our knowledge, this is the first report that has studied the effect of CCR on cold-active sialidase, produced by an Antarctic strain.
PubMed: 38667912
DOI: 10.3390/jof10040241 -
Insects Apr 2024Alterative nutritional foods consumed by adult parasitoids play an important role in their fitness and ability to control pests because of food scarcity in many crops....
Alterative nutritional foods consumed by adult parasitoids play an important role in their fitness and ability to control pests because of food scarcity in many crops. While adult parasitoids feed on various sugars, they vary in their nutritional value for parasitoids. We assessed the effects of seven sugars (fructose, glucose, sucrose, trehalose, maltose, melezitose, and sorbitol) on the longevity, parasitism ability, parasitism behavior, and flight ability of , an important parasitoid of cotton aphids. We found that access to glucose, sucrose, or fructose, increased adult longevity more than the other sugars offered. All sugars except trehalose increased the parasitism rate to more than 50% compared to the starved control (only provided with water). We then compared parasitoid behaviors of wasps fed glucose, sucrose, or fructose to that of the starved control (with access only to water) and found that those fed spent more time either examining or attacking aphids than parasitoids in the control group, which spent more time walking or resting. Also, consumption of glucose, sucrose, or fructose also significantly improved the flight ability (the total flight distance, flight time, and average flight speed) of .
PubMed: 38667375
DOI: 10.3390/insects15040245 -
Frontiers in Microbiology 2024Lanzhou lily ( var. ) is an exclusive sweet lily variety indigenous to China, which is susceptible to bulbous rot caused by fungal infection during storage. This...
Lanzhou lily ( var. ) is an exclusive sweet lily variety indigenous to China, which is susceptible to bulbous rot caused by fungal infection during storage. This experiment tests the pathogenicity of the pure culture isolated from the diseased tissue was confirmed in accordance with Koch's postulates, and the pathomycetes were identified based on their morphological and molecular characteristics. Furthermore, the biological characteristics of the pathogens were investigated, followed by an evaluation of the antifungal effects of three plant essential oils against them. The results showed that two strains of fungi were isolated from Lanzhou lily rot, which were identified as Schl. and (Bain. Et sart.). In addition, the pathogenicity of these two strains of fungi was demonstrated that only induced rot with similar symptoms during the post-harvest storage period. The biological characteristics of indicated the potato maltose agar and lily dextrose agar were identified as the most suitable media. Sucrose was determined to be the optimal carbon source, while ammonium nitrate was found to be the best nitrogen source for the growth of . Mycelial growth and sporulation of occurred at an optimum pH value of 6. Total darkness facilitated mycelial growth and conidial germination. The ideal temperature for growth was found to be 28°C, while relative humidity did not significantly impact mycelial growth; however, a relative humidity of 55% was most favorable for spore production. Among the three essential oils tested, cinnamon essential oil displayed superior antifungal efficacy against , whereas angelica essential oil and tea tree essential oil also exhibited moderate inhibitory effects against this pathogen. This research provides valuable theoretical insights for disease control during the storage and transportation of Lanzhou lily.
PubMed: 38666262
DOI: 10.3389/fmicb.2024.1307966 -
Bioresources and Bioprocessing Jan 2024The bioconversion of 4-hydroxy-2-keto acid derivatives via aldol condensation of formaldehyde and pyruvate has received substantial attention as potential source of...
The bioconversion of 4-hydroxy-2-keto acid derivatives via aldol condensation of formaldehyde and pyruvate has received substantial attention as potential source of chemicals for production of amino acids, hydroxy carboxylic acids, and chiral aldehydes. We developed an environmentally friendly biocatalyst consisting of a novel thermostable class II pyruvate aldolase from Deinococcus radiodurans with maltose-binding protein (MBP-DrADL), which has specific activity of 46.3 µmol min mg. Surprisingly, MBP-DrADL maintained over 60% of enzyme activity for 4 days at 50 to 65 °C, we used MBP-DrADL as the best candidate enzyme to produce 2-keto-4-hydroxybutyrate (2-KHB) from formaldehyde and pyruvate via aldol condensation. The optimum reaction conditions for 2-KHB production were 50 °C, pH 8.0, 5 mM Mg, 100 mM formaldehyde, and 200 mM pyruvate. Under these optimized conditions, MBP-DrADL produced 76.5 mM (8.94 g L) 2-KHB over 60 min with a volumetric productivity of 8.94 g L h and a specific productivity of 357.6 mg mg-enzyme h. Furthermore, 2-KHB production was improved by continuous addition of substrates, which produced approximately 124.8 mM (14.6 g L) of 2-KHB over 60 min with a volumetric productivity and specific productivity of 14.6 g L h and 583.4 mg mg-enzyme h, respectively. MBP-DrADL showed the highest specific productivity for 2-KHB production yet reported. Our study provides a highly efficient biocatalyst for the synthesis of 2-KHB and lays the foundation for large-scale production and application of high-value compounds from formaldehyde.
PubMed: 38647973
DOI: 10.1186/s40643-024-00727-x -
Bioresources and Bioprocessing Sep 2023Trehalose is a functional sugar that has numerous applications in food, cosmetic, and pharmaceutical products. Production of trehalose from maltose via a single-step...
Trehalose is a functional sugar that has numerous applications in food, cosmetic, and pharmaceutical products. Production of trehalose from maltose via a single-step enzymatic catalysis using trehalose synthase (TreS) is a promising method compared with the conventional two-step process due to its simplicity with lower formation of byproducts. In this study, a cold-active trehalose synthase (PaTreS) from Pseudarthrobacter sp. TBRC 2005 was heterologously expressed and characterized. PaTreS showed the maximum activity at 20 °C and maintained 87% and 59% of its activity at 10 °C and 4 °C, respectively. The enzyme had remarkable stability over a board pH range of 7.0-9.0 with the highest activity at pH 7.0. The activity was enhanced by divalent metal ions (Mg, Mn and Ca). Conversion of high-concentration maltose syrup (100-300 g/L) using PaTreS yielded 71.7-225.5 g/L trehalose, with 4.5-16.4 g/L glucose as a byproduct within 16 h. The work demonstrated the potential of PaTreS as a promising biocatalyst for the development of low-temperature trehalose production, with the advantages of reduced risk of microbial contamination with low generation of byproduct.
PubMed: 38647947
DOI: 10.1186/s40643-023-00681-0