Large volumes of fruit and vegetable production are lost during postharvest handling due to attacks by necrotrophic fungi. One of the promising alternatives proposed for the control of postharvest ...diseases is the induction of natural defense responses, which can be activated by recognizing molecules present in pathogens, such as chitin. Chitin is one of the most important components of the fungal cell wall and is recognized through plant membrane receptors. These receptors belong to the receptor-like kinase (RLK) family, which possesses a transmembrane domain and/or receptor-like protein (RLP) that requires binding to another RLK receptor to recognize chitin. In addition, these receptors have extracellular LysM motifs that participate in the perception of chitin oligosaccharides. These receptors have been widely studied in
(
) and
(
); however, it is not clear how the molecular recognition and plant defense mechanisms of chitin oligosaccharides occur in other plant species or fruits. This review includes recent findings on the molecular recognition of chitin oligosaccharides and how they activate defense mechanisms in plants. In addition, we highlight some of the current advances in chitin perception in horticultural crops.
Aquaculture is one of the fastest-growing food-producing sectors worldwide and tilapia (Oreochromis spp.) farming constitutes the major freshwater fish variety cultured. Because aquaculture practices ...are susceptible to microbial contamination derived from anthropogenic sources, extensive antibiotic usage is needed, leading to aquaculture systems becoming an important source of antibiotic-resistant and pathogenic bacteria of clinical relevance such as Escherichia coli (E. coli). Here, the antimicrobial resistance, virulence, and mobilome features of a pathogenic E. coli strain, recovered from inland farmed Oreochromis spp., were elucidated through whole-genome sequencing (WGS) and in silico analysis. Antimicrobial susceptibility testing (AST) and WGS were performed. Furthermore, phylogenetic group, serotype, multilocus sequence typing (MLST), acquired antimicrobial resistance, virulence, plasmid, and prophage content were determined using diverse available web tools. The E. coli isolate only exhibited intermediate susceptibility to ampicillin and was characterized as ONT:H21-B1-ST40 strain by WGS-based typing. Although only a single antimicrobial resistance-related gene was detected mdf(A), several virulence-associated genes (VAGs) from the atypical enteropathogenic E. coli (aEPEC) pathotype were identified. Additionally, the cargo of plasmid replicons from large plasmid groups and 18 prophage-associated regions were detected. In conclusion, the WGS characterization of an aEPEC isolate, recovered from a fish farm in Sinaloa, Mexico, allows insights into its pathogenic potential and the possible human health risk of consuming raw aquacultural products. It is necessary to exploit next-generation sequencing (NGS) techniques for studying environmental microorganisms and to adopt a one health framework to learn how health issues originate.
The impact of contamination of water drainage ditches in the development of antibiotic-resistant bacteria has been scarcely studied in Mexico. In this regard, 101 isolates of E. coli were obtained ...from water samples from a ditch in Sinaloa, during one year. The antimicrobial resistant profiles, the presence of the class 1 integron and evolutionary relationship of intI1 sequences were determined. The 47.5% of strains were resistant and 5.9% multidrug resistant (MDR) with an average multiple antibiotic resistance index value of 0.45. The highest resistance was registered with β-lactam (39.6%) and quinolone (9.9%). The intI1 gene was detected in 11.9% of the isolates, and no association with MDR was found. Sequence were associated with human and animal host isolates. MDR E. coli isolates with intI1 gene highlight the potential risk of the ditch's water to human health. An attenuation effect of MDR E. coli isolates in the outlet water was observed.
Fresh horticultural products are economically significant foods that are highly demanded by consumers worldwide; however, they are highly perishable and susceptible to deterioration by fungi, which ...contribute to their short shelf-life and cause significant post-harvest losses. Among the alternatives suggested for fungal control in plants is the elicitation of the innate plant defense mechanism, which may be activated when specific molecules of the phytopathogen, such as chitin, are recognized. Chitin is a long-chain polymer of N-acetyl-α-D-glucosamine of the fungal cell wall; it possesses biological activity by eliciting the plant immune response. This molecule and its oligosaccharides are recognized through transmembrane receptors known as receptor-like kinases (RLKs) and receptor-like proteins (RLPs). Mediated by receptor-like cytoplasmic kinases (RLCKs), which bind to the intracellular domain of these receptors, they initiate intracellular signal transduction via MAP kinases, triggering the plant defense response. In model plants, such as Oryza sativa (rice) and Arabidopsis thaliana, the set of RLK/RLP-RLCK-MAP kinases is involved in plant immunity triggered by chitin. Furthermore, in horticultural products, research into the molecular events between these three elements has suggested that similar processes occur. However, little is known about these molecular events in fruits. Against this background, the present review provides the most recent and relevant findings on the molecular associations of these three elements in the response to fungal chitin in plants and outlines which elements could participate in this signaling process in horticultural crops.
The tomato is an economically important crop worldwide, although fungal infections by Alternaria alternata are the main cause of large postharvest fruit losses. One alternative to chemical control is ...the induction of the defense mechanism of plants with natural molecules such as chitin. Chitin is a polysaccharide of the fungal cell wall that is recognized by plasma membrane receptors that activates the transcription of plant defense genes. Because there is little information on the genes involved in chitin perception and defense responses to fungal chitin oligomers in tomato fruits, the main objective of this study was to identify pattern recognition receptor-associated genes in tomato fruits that perceive chitin oligomers from the necrotrophic fungus A. alternata using RNA-Seq. Chitin oligomers were obtained from A. alternata via enzymatic treatment. Tomato fruits in the pink ripening stage were exposed to these chitin oligomers for 30 min. The induction of tomato genes encoding a plasma membrane receptor that recognizes fungal chitin (LRR, RLK, SlLYK4, and SlCERK1) was observed 30 min after treatment. Similarly, the perception of Alternaria chitin oligomers triggered the induction of genes involved in signaling pathways regulated by ethylene and jasmonic acid. Further, activation of plant defense phenomena was confirmed by the upregulation of several genes encoding pathogenesis-related proteins. The scientific information generated in the present work will help to better elucidate tomato fruit’s response to pathogens and to design protocols to reduce postharvest losses due to fungal infection.
•HT-Ca delayed anthracnose appearance on papaya.•Mycelial growth was inhibited by HT-Ca.•HT-Ca melted the cuticular wax and covered fruit stomata.
Anthracnose is considered an important postharvest ...disease in papaya. The hydrothermal treatment (HT) and calcium chloride (Ca) have been shown to be effective to inhibit anthracnose. The objective of this study was to investigate the effect of the combination HT-Ca on the development of anthracnose in papaya. Fruit were inoculated with Colletotrichum gloeosporioides by immersion in a spore suspension and then were divided into two groups: one received a HT treatment (48°C, 20min) combined with Ca (1% w/v, 20min) and the other was used as control. Afterwards, fruit were stored during 20days at 12°C to allow the development of the fungal infection. Anthracnose incidence and severity were estimated visually while the development of the disease was analyzed by light and electron microscopy. HT-Ca reduced anthracnose incidence and severity compared with the control. Microscopy analysis showed that HT-Ca melted the epicuticular wax, which covered most of the stomata; this resulted in a lower mycelial growth in HT-Ca fruit with respect to the control samples. HT-Ca also induced the formation of round shaped vesicles, which corresponded with the greater accumulation of total phenolics observed in treated fruit. HT-Ca was effective to delay the symptoms of anthracnose up to 10days during storage of papaya at 12°C.
The increasing prevalence and complications related to liver diseases (caused by infection, toxic agents, or metabolic syndrome), together with insufficient existence of treatments, make evident the ...need for better therapeutic alternatives. Therefore, the aim of this study was to determine the effect of 4-hydroxychalcone (4-HC) as preventive and curative treatment in acute and chronic liver injury, respectively. Liver damage was induced with carbon tetrachloride (CCl.sub.4) in Wistar rats. Rats were divided into two groups: (1) acute liver injury and (2) chronic liver injury. In turn, each group was divided into four subgroups: (i) control (water); (ii) dimethyl sulfoxide 10%; (iii) CCl.sub.4; and (iv) 4-HC. The pre-treatment with 4-HC decreased transaminases, IL-6 serum levels, and hepatic malondialdehyde, increased IL-10 serum levels and hepatic glutathione, and decreased liver damage (necrosis, steatosis, and inflammatory infiltrate). In contrast, treatment with 4-HC after the induction of chronic liver injury decreased IL-6 serum levels and liver damage (steatosis, inflammatory infiltrate, ballooning cells, steatofibrosis, and fibrosis degree). Thus, the 4-HC treatment is proposed as a preventive treatment against acute liver injury; moreover, these results suggested the potential of 4-HC as a curative treatment against chronic liver injury, but other scheme treatments must be evaluated in future.
Celotno besedilo
Dostopno za:
DOBA, FSPLJ, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
•Echeveria plants are used as traditional medicines but have been scarcely studied.•Studied Echeveria species showed high antioxidant and antimutagenic activities.•The chemical profiles of the ...studied Echeveria plants showed clear differences.•Activities of the species of Echeveria were associated with specific compounds.•Studied Echeveria species have components which can be used for pharmaceuticals.
In order to preserve plant biodiversity by its sustainable use, valuable plant products must be identified to induce the field production of specific species. Echeveria is the most representative genus from Crassulaceae of Mexico because its high endemism, historical–cultural significance and role in arid ecosystems of the country. Echeveria species have important biological activities, but their compounds have not been identified. The objective of the study was to determine biological activities (i.e., antimutagenic and antioxidant) and chemical composition by GC–MS of Echeveria kimnachii (EK) and Echeveria subrigida (ES) leaves. Methanol extracts of leaves were liquid–liquid partitioned to get the hexane (HF), ethyl acetate (EAF), and aqueous (AqF) fractions and they were analyzed. Methanol extracts and their fractions (500μg/plate) showed mutagenicity inhibition (>45%) in the Ames assay using Salmonella Typhimurium YG1024 and 1-nitropyrene (200ng/plate), and the most active fractions were HF-EK (91.8%) and EAF-ES (97.6%). The highest antioxidant activities (AA) were for EAFs by DPPH (inhibition %: EK=67.5 and ES=95.1) and β-carotene-bleaching (AA %: EK=57.1 and ES=41.6) methods. GC–MS profiles showed clear differences among EK and ES, hopenone b was specific for EK and brassicasterol and germanicol for ES. The high content of phenolics (i.e., isorhamnetin and gallic acid for ES) and organic acids (i.e., syringic and malic for EK) was associated with the highest antioxidant activities of the EAFs, and with the highest antimutagenic activity of EAF-ES. By contrast, HF-EK is high in sterols (i.e., lupenone, hopenone b and γ-sitosterol) which could be responsible of its strong antimutagenicity. Moreover, both Echeveria showed other secondary metabolites (e.g., phytosterols, terpenes and fatty acids) with published remarkable biological activities. Thus, E. kimnachii and E. subrigida could be sources of biological active compounds for pharmaceutical and nutraceutical industries.
Urinary tract infections (UTIs) caused by multidrug-resistant and extended-spectrum β-lactamase-producing uropathogenic
are a worldwide concern. We report the draft genome of
U13824 isolated from a ...female outpatient with UTI. This genome's availability strengthens the genomic surveillance of antimicrobial resistance and the spreading of these strains.
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