Rhizoctonia
Mitosporic Fungi
Monarda
Trichoderma
Pest Control, Biological
Antibiosis
Pythium
Fungi
Beta vulgaris
Fungicides, Industrial
Chitinase
Hydrogen Cyanide
Role of the Trichoderma harzianum endochitinase gene, ech42, in mycoparasitism. (1/153)
The role of the Trichoderma harzianum endochitinase (Ech42) in mycoparasitism was studied by genetically manipulating the gene that encodes Ech42, ech42. We constructed several transgenic T. harzianum strains carrying multiple copies of ech42 and the corresponding gene disruptants. The level of extracellular endochitinase activity when T. harzianum was grown under inducing conditions increased up to 42-fold in multicopy strains as compared with the wild type, whereas gene disruptants exhibited practically no activity. The densities of chitin labeling of Rhizoctonia solani cell walls, after interactions with gene disruptants were not statistically significantly different than the density of chitin labeling after interactions with the wild type. Finally, no major differences in the efficacies of the strains generated as biocontrol agents against R. solani or Sclerotium rolfsii were observed in greenhouse experiments. (+info)Cellulolytic enzymes in culture filtrates of Rhizoctonia lamellifera. (2/153)
During growth in a liquid culture containing a single soluble or an insoluble cellulosic carbon source, Rhizoctonia lamellifera released cellulolytic enzymes into the medium. These enzymes were separated by gel filtration and ion-exchange chromatography into seven components, three of high and four of low molecular weight. One of the components had the character of a C1 cellulase. When the components were combined they released more reducing sugars from cellulosic substrates than when used singly. (+info)Predicting variability in biological control of a plant-pathogen system using stochastic models. (3/153)
A stochastic model for the dynamics of a plant-pathogen interaction is developed and fitted to observations of the fungal pathogen Rhizoctonia solani (Kuhn) in radish (Raphanus sativus L.), in both the presence and absence of the antagonistic fungus Trichoderma viride (Pers ex Gray). The model incorporates parameters for primary and secondary infection mechanisms and for characterizing the time-varying susceptibility of the host population. A parameter likelihood is developed and used to fit the model to data from microcosm experiments. It is shown that the stochastic model accounts well for observed variability both within and between treatments. Moreover, it enables us to describe the time evolution of the probability distribution for the variability among replicate epidemics in terms of the underlying epidemiological parameters for primary and secondary infection and decay in susceptibility. Consideration of profile likelihoods for each parameter provides strong evidence that T. viride mainly affects primary infection. By using the stochastic model to study the dependence of the probability distribution of disease levels on the primary infection rate we are therefore able to predict the effectiveness of a widely used biological control agent. (+info)Enzyme diffusion from Trichoderma atroviride (= T. harzianum P1) to Rhizoctonia solani is a prerequisite for triggering of Trichoderma ech42 gene expression before mycoparasitic contact. (4/153)
A plate confrontation experiment is commonly used to study the mechanism by which Trichoderma spp. antagonize and parasitize other fungi. Previous work with chitinase gene expression (ech42) during the precontact period of this process in which cellophane and dialysis membranes separated Trichoderma harzianum and its host Rhizoctonia solani resulted in essentially opposite results. Here, we show that cellophane membranes are permeable to proteins up to at least 90 kDa in size but that dialysis membranes are not. ech42 was expressed during the precontact stage of the confrontation between Trichoderma atroviride and its host only if the cellophane was placed between the two fungi. These results are consistent with enzyme diffusion from T. atroviride to R. solani generating the trigger of ech42 gene expression. (+info)Isolation and identification of antifungal N-butylbenzenesulphonamide produced by Pseudomonas sp. AB2. (5/153)
An antifungal bacterial strain, isolated from a greenhouse soil sample, inhibits growth of microflora nearby. It was selected for further studies of bacterial antifungal properties. This isolate was identified as a Pseudomonas sp. based on carbohydrate utilization, and other biochemical and physiological tests. Petri plate assay revealed that the Pseudomonas sp. exhibited antifungal activity against the plant pathogens, Pythium ultimum, Rhizoctonia solani, Phytophthora capsici, Botrytis cinerea and Fusarium oxysporum. Using direct inhibition bioassay on TLC plates after ethyl acetate extraction of the culture filtrate, we correlated antifungal activity with production of antifungal compounds. An antifungal antibiotic was isolated from the culture filtrate and was identified as N-butylbenzenesulphonamide. ED50, values of the N-butylbenzenesulphonamide against P. ultimum, P. capsici, R. solani, and B. cinerea were 73, 41, 33 and 102 ppm, respectively. (+info)Mapping the growth of fungal hyphae: orthogonal cell wall expansion during tip growth and the role of turgor. (6/153)
By computer-enhanced videomicroscopy, we mapped the trajectory of external and internal cell surface markers in growing fungal hyphae to determine the pattern of cell wall expansion during apical growth. Carbon particles (India ink) were chosen as external markers for tip expansion of Rhizoctonia solani hyphae. Irregularities in the growing apical walls of R. solani served as internal markers. Marker movement was traced in captured frames from the videotaped sequences. External and internal markers both followed orthogonal trajectories; i.e., they moved perpendicular to the cell surface regardless of their initial position in the hyphal apex. We found no evidence that the tip rotates during elongation. The discovery that the cell wall of a growing hypha expands orthogonally has major repercussions on two fronts: 1) It supports the long-held view that turgor pressure is the main force driving cell wall expansion. 2) It provides crucial information to complete the mathematical derivation of a three-dimensional model of hyphal morphogenesis based on the vesicle supply center concept. In three dimensions, the vesicle gradient generated by the vesicle supply center is insufficient to explain shape; it is also necessary to know the manner in which the existing surface is displaced during wall expansion. (+info)Syntheses and biological activities of pyranyl-substituted cinnamates. (7/153)
Twenty-two kinds of pyranyl-substituted cinnamates were synthesized by the reaction of 4-hydroxy-6-(2-phenylethyl)-2H-pyran-2-one or 4-hydroxy-6-methyl-2H-pyran-2-one (HMP) with a variety of substituted cinnamic acids, and their antifungal and plant growth inhibitory activities were investigated. Among the compounds prepared, 6-methyl-2-oxo-2H-pyran-4-yl 3-(4-isopropylphenyl)propenoate (H5) showed the strongest antifungal activity against Rhizoctonia solani and Sclerotium dellfinii, and 6-methyl-2-oxo-2H-pyran-4-yl 3-(2-methylphenyl)propenoate (H2) had the highest plant growth inhibitory activity toward Brassica rapa. (+info)Induction of laccase activity in Rhizoctonia solani by antagonistic Pseudomonas fluorescens strains and a range of chemical treatments. (8/153)
Fungi often produce the phenoloxidase enzyme laccase during interactions with other organisms, an observation relevant to the development of biocontrols. By incorporating the laccase substrate 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) into agar, we analyzed laccase induction in the plant-pathogenic fungus Rhizoctonia solani when paired against isolates of the soil bacterium Pseudomonas fluorescens. Substantial induction of R. solani laccase was seen only in pairings with strains of P. fluorescens known to produce antifungal metabolites. To study laccase induction further, a range of chemical treatments was applied to R. solani liquid cultures. p-Anisidine, copper(II), manganese(II), calcium ionophore A23187, lithium chloride, calcium chloride, cyclic AMP (cAMP), caffeine, amphotericin B, paraquat, ethanol, and isopropanol were all found to induce laccase; however, the P. fluorescens metabolite viscosinamide did not do so at the concentrations tested. The stress caused by these treatments was assessed by measuring changes in lipid peroxidation levels and dry weight. The results indicated that the laccase induction seen in pairing plate experiments was most likely due to calcium or heat shock signaling in response to the effects of bacterial metabolites, but that heavy metal and cAMP-driven laccase induction was involved in sclerotization. (+info)Rhizoctonia is a genus of saprophytic and facultative parasitic fungi that belong to the order Corticiales. It is widely distributed in soil and on plant debris, and can cause various plant diseases known as "rhizoctonioses." The most common species associated with plant pathogenicity is Rhizoctonia solani. These fungi infect a wide range of plants, including crops, turfgrass, and ornamentals, causing symptoms such as root rot, stem canker, damping-off, and wirestem blight. The fungus can also form sclerotia, which are compact masses of hardened fungal mycelium that can survive in the soil for many years, serving as a source of infection for future plant growth.
Mitosporic fungi, also known as asexual fungi or anamorphic fungi, are a group of fungi that produce mitospores (also called conidia) during their asexual reproduction. Mitospores are produced from the tip of specialized hyphae called conidiophores and are used for dispersal and survival of the fungi in various environments. These fungi do not have a sexual reproductive stage or it has not been observed, making their taxonomic classification challenging. They are commonly found in soil, decaying organic matter, and water, and some of them can cause diseases in humans, animals, and plants. Examples of mitosporic fungi include Aspergillus, Penicillium, and Fusarium species.
A plant disease is a disorder that affects the normal growth and development of plants, caused by pathogenic organisms such as bacteria, viruses, fungi, parasites, or nematodes, as well as environmental factors like nutrient deficiencies, extreme temperatures, or physical damage. These diseases can cause various symptoms, including discoloration, wilting, stunted growth, necrosis, and reduced yield or productivity, which can have significant economic and ecological impacts.
I'm sorry for any confusion, but "Monarda" is not a medical term. It is the genus name for a group of plants commonly known as bee balms or bergamots. These herbaceous perennials are native to North America and are part of the mint family (Lamiaceae). Some people use the leaves and flowers of Monarda species in teas and other culinary applications, and some Native American tribes have used them for medicinal purposes. However, there is limited scientific evidence supporting their effectiveness as medical treatments.
Trichoderma is a genus of fungi that are commonly found in soil, decaying wood, and other organic matter. While there are many different species of Trichoderma, some of them have been studied for their potential use in various medical and industrial applications. For example, certain Trichoderma species have been shown to have antimicrobial properties and can be used to control plant diseases. Other species are being investigated for their ability to produce enzymes and other compounds that may have industrial or medicinal uses.
However, it's important to note that not all Trichoderma species are beneficial, and some of them can cause infections in humans, particularly in individuals with weakened immune systems. These infections can be difficult to diagnose and treat, as they often involve multiple organ systems and may require aggressive antifungal therapy.
In summary, Trichoderma is a genus of fungi that can have both beneficial and harmful effects on human health, depending on the specific species involved and the context in which they are encountered.
Biological pest control, also known as biocontrol, is a method of managing or eliminating pests such as insects, mites, weeds, and plant diseases using natural enemies or other organisms. These biological control agents include predators, parasites, pathogens, and competitors that regulate pest populations and reduce the need for chemical pesticides. Biological pest control is a key component of integrated pest management (IPM) programs and has minimal impact on the environment compared to traditional pest control methods.
Mycelium is not a specifically medical term, but it is a biological term used in fungi and other organisms. Medically, it might be relevant in certain contexts such as discussing fungal infections. Here's the general definition:
Mycelium (my-SEE-lee-um) is the vegetative part of a fungus, consisting of a mass of branching, thread-like hyphae. It is the underground portion of the fungus that supports the growth of the organism and is often responsible for the decomposition of organic material. Mycelium can be found in various environments, including soil, water, and dead or living organisms.
Antibiosis is a type of interaction between different organisms in which one organism, known as the antibiotic producer, produces a chemical substance (known as an antibiotic) that inhibits or kills another organism, called the susceptible organism. This phenomenon was first discovered in bacteria and fungi, where certain species produce antibiotics to inhibit the growth of competing species in their environment.
The term "antibiosis" is derived from Greek words "anti" meaning against, and "biosis" meaning living together. It is a natural form of competition that helps maintain the balance of microbial communities in various environments, such as soil, water, and the human body.
In medical contexts, antibiosis refers to the use of antibiotics to treat or prevent bacterial infections in humans and animals. Antibiotics are chemical substances produced by microorganisms or synthesized artificially that can inhibit or kill other microorganisms. The discovery and development of antibiotics have revolutionized modern medicine, saving countless lives from bacterial infections that were once fatal.
However, the overuse and misuse of antibiotics have led to the emergence of antibiotic-resistant bacteria, which can no longer be killed or inhibited by conventional antibiotics. Antibiotic resistance is a significant global health concern that requires urgent attention and action from healthcare providers, policymakers, and the public.
Pythium is a genus of microscopic, aquatic fungus-like organisms called oomycetes. They are commonly referred to as water molds and can be found in various environments such as soil, freshwater, and marine habitats. Some species of Pythium are known to cause plant diseases, while others can infect animals, including humans, causing a variety of conditions primarily related to the eye and skin.
In human medicine, Pythium insidiosum is the most relevant species, as it can cause a rare but severe infection called pythiosis. This infection typically affects the eyes (keratopythiosis) or the gastrointestinal tract (gastrointestinal pythiosis). The infection occurs through direct contact with contaminated water or soil, and it is more prevalent in tropical and subtropical regions.
Pythium insidiosum produces filamentous structures called hyphae that can invade and damage tissues, leading to the formation of granulomatous lesions. The infection can be difficult to diagnose and treat due to its rarity and the limited number of effective antifungal agents available. Surgical intervention and immunotherapy are often necessary in addition to medical treatment for successful management.
Fungi, in the context of medical definitions, are a group of eukaryotic organisms that include microorganisms such as yeasts and molds, as well as the more familiar mushrooms. The study of fungi is known as mycology.
Fungi can exist as unicellular organisms or as multicellular filamentous structures called hyphae. They are heterotrophs, which means they obtain their nutrients by decomposing organic matter or by living as parasites on other organisms. Some fungi can cause various diseases in humans, animals, and plants, known as mycoses. These infections range from superficial, localized skin infections to systemic, life-threatening invasive diseases.
Examples of fungal infections include athlete's foot (tinea pedis), ringworm (dermatophytosis), candidiasis (yeast infection), histoplasmosis, coccidioidomycosis, and aspergillosis. Fungal infections can be challenging to treat due to the limited number of antifungal drugs available and the potential for drug resistance.
'Beta vulgaris' is the scientific name for a group of plants that includes several common vegetables such as beets, chard, and sugar beets. This species is native to coastal regions of Europe, North Africa, and Asia.
Beets, also known as table beets or garden beets, are grown for their edible roots, which can be red, yellow, or striped. They have a sweet, earthy flavor and are often eaten raw, pickled, or cooked. Beet greens, the leaves of the plant, are also edible and have a mild flavor similar to spinach.
Chard, also known as Swiss chard, is grown for its large, colorful leaves that can be green, red, yellow, or white. The leaves and stems are both edible and have a slightly bitter taste. Chard is often used in salads, soups, and stir-fries.
Sugar beets are grown for their roots, which contain high levels of sucrose. They are used to produce granulated sugar, molasses, and other sweeteners. Sugar beets are not typically eaten as a vegetable, but the leaves can be consumed in the same way as chard.
In summary, 'Beta vulgaris' is a versatile species of plant that includes several popular vegetables, including beets, chard, and sugar beets.
Industrial fungicides are antimicrobial agents used to prevent, destroy, or inhibit the growth of fungi and their spores in industrial settings. These can include uses in manufacturing processes, packaging materials, textiles, paints, and other industrial products. They work by interfering with the cellular structure or metabolic processes of fungi, thereby preventing their growth or reproduction. Examples of industrial fungicides include:
* Sodium hypochlorite (bleach)
* Formaldehyde
* Glutaraldehyde
* Quaternary ammonium compounds
* Peracetic acid
* Chlorhexidine
* Iodophors
It's important to note that some of these fungicides can be harmful or toxic to humans and other organisms, so they must be used with caution and in accordance with safety guidelines.
Chitinase is an enzyme that breaks down chitin, a complex carbohydrate and a major component of the exoskeletons of arthropods, the cell walls of fungi, and the microfilamentous matrices of many invertebrates. Chitinases are found in various organisms, including bacteria, fungi, plants, and animals. In humans, chitinases are involved in immune responses to certain pathogens and have been implicated in the pathogenesis of several inflammatory diseases, such as asthma and chronic obstructive pulmonary disease (COPD).
Hydrogen Cyanide (HCN) is a chemical compound with the formula H-C≡N. It is a colorless, extremely poisonous and flammable liquid that has a bitter almond-like odor in its pure form. However, not everyone can detect its odor, as some people lack the ability to smell it, which makes it even more dangerous. It is soluble in water and alcohol, and its aqueous solution is called hydrocyanic acid or prussic acid.
Hydrogen Cyanide is rapidly absorbed by inhalation, ingestion, or skin contact, and it inhibits the enzyme cytochrome c oxidase, which is essential for cellular respiration. This leads to rapid death due to hypoxia (lack of oxygen) at the cellular level. It is used industrially in large quantities as a pesticide, fumigant, and chemical intermediate, but it also has significant potential for use as a chemical weapon.
In the medical field, Hydrogen Cyanide poisoning can be treated with high-concentration oxygen, sodium nitrite, and sodium thiosulfate, which help to restore the function of cytochrome c oxidase and enhance the elimination of cyanide from the body.
I apologize, but there seems to be a misunderstanding. "Soil microbiology" is not a medical term; rather, it is a branch of microbiology that deals with the study of microorganisms in soil. It involves understanding the diversity, ecology, and biochemistry of bacteria, fungi, algae, protozoa, and other microscopic life forms found in soil. This field has applications in agriculture, environmental science, and waste management but is not directly related to medical definitions or human health.