Malus
Rosales
Erwinia amylovora
Rosaceae
Prunus
Gene Expression Regulation, Plant
Endo-1,3(4)-beta-Glucanase
The relationship between photosystem II efficiency and quantum yield for CO(2) assimilation is not affected by nitrogen content in apple leaves. (1/489)
Bench-grafted Fuji/M.26 apple (Malus domestica Borkh.) trees were fertigated with different concentrations of nitrogen by using a modified Hoagland's solution for 45 d. CO(2) assimilation and photosystem II (PSII) quantum efficiency in response to incident photon flux density (PFD) were measured simultaneously in recent fully expanded leaves under low O(2) (2%) and saturated CO(2) (1300 micromol mol(-1)) conditions. A single curvilinear relationship was found between true quantum yield for CO(2) assimilation and PSII quantum efficiency for leaves with a wide range of leaf N content. The relationship was linear up to a quantum yield of approximately 0.05 mol CO(2) mol(-1) quanta. It then became curvilinear with a further rise in quantum yield in response to decreasing PFD. This relationship was subsequently used as a calibration curve to assess the rate of non-cyclic electron transport associated with Rubisco and the partitioning of electron flow between CO(2) assimilation and photorespiration in different N leaves in response to intercellular CO(2) concentration (C(i)) under normal O(2) conditions. Both the rate of non-cyclic electron flow and the rate of electron flow to CO(2) or O(2) increased with increasing leaf N at any given C(i). The percentage of non-cyclic electron flow to CO(2) assimilation, however, remained the same regardless of leaf N content. As C(i) increased, the percentage of non-cyclic electron flow to CO(2) assimilation increased. In conclusion, the relationship between PSII quantum efficiency and quantum yield for CO(2) assimilation and the partitioning of electron flow between CO(2) assimilation and photorespiration are not affected by N content in apple leaves. (+info)Local modulation of host pH by Colletotrichum species as a mechanism to increase virulence. (2/489)
The phytopathogenic fungus Colletotrichum gloeosporioides produces one pectate lyase (PL) that is a key virulence factor in disease development. During growth of C. gloeosporioides, Colletotrichum acutatum, and Colletotrichum coccodes in acidified yeast extract medium, the fungus secreted ammonia and increased the medium pH. Ammonia accumulation and the consequent pH change increased as a function of initial pH and buffer capacity of the medium. PL secretion by C. gloeosporioides correspondingly increased as the pH of the medium increased. The C. gloeosporioides pelB gene-disrupted mutant was able to increase ammonia accumulation and pH of the media similarly to the wild-type isolate. C. gloeosporioides in avocado, C. coccodes in tomato, and C. acutatum in apple showed ammonia accumulation in the infected area where pH increased to 7.5 to 8 and PL activity is optima. In nonhost interactions where C. gloeosporioides was inoculated in apples, the addition of ammonia-releasing compounds significantly enhanced pathogenicity to levels similar to those caused by the compatible C. acutatum-apple interaction. The results therefore suggest the importance of ammonia secretion as a virulence factor, enhancing environmental pH and pathogenicity of the Colletotrichum species. (+info)Abscisic acid-specific binding sites in the flesh of developing apple fruit. (3/489)
Abscisic acid (ABA) specific-binding sites localized in the cytosol were identified and characterized in the flesh of developing apple (Malus pumila L. cv. Starkrimon) fruit. ABA binding activity was scarcely detectable in the microsomes but high ABA binding activity in the cytosolic fraction was detected. The ABA-binding sites possessed a protein nature with both active serine residues and thiol-groups of cysteine residues in their functional binding sites. ABA binding was shown to be saturable, reversible and of high affinity. A Scatchard plot provided evidence for two different ABA binding proteins, one with higher affinity (K(d)=2.3 nM) and the other with lower affinity (K(d)=58.8 nM). Phaseic acid, trans-ABA and (-)-ABA had essentially no affinity for the binding proteins, indicating their stereo-specificity to bind physiologically active cis-(+)-ABA. The time-course, pH- and temperature-dependence of the ABA-binding proteins were determined. It is hypothesized that the detected ABA-binding proteins may be putative ABA-receptors that mediate ABA signals during fruit development. (+info)Inoculation onto solid surfaces protects Salmonella spp. during acid challenge: a model study using polyethersulfone membranes. (4/489)
Salmonellae are the most frequently reported cause of outbreaks of food-borne gastroenteritis in the United States. In clinical trials, the oral infective dose (ID) for healthy volunteers was estimated to be approximately 1 million cells. However, in reports from various outbreaks, the ID of Salmonella species associated with solid foods was estimated to be as few as 100 cells. We found that fresh-cut produce surfaces not only provided suitable solid support for pathogen attachment but also played a critical role in increasing the acid tolerance of the pathogen. However the acidic nature of certain produce played no role in making salmonellae resistant to stomach acidity. Inoculation onto fresh-cut produce surfaces, as well as onto inert surfaces, such as polyethersulfone membranes and tissue paper, increased the survival of salmonellae during acid challenge (50 mM Na-citrate, pH 3.0; 37 degrees C; 2 h) by 4 to 5 log units. Acid challenge experiments using cells inoculated onto polyethersulfone membranes provided a model system suitable for studying the underlying fundamentals of the protection that occurs when Salmonella strains are associated with solid foods. The surface-associated acid protection, which was observed in several Salmonella strains, required de novo protein synthesis and was independent of stationary-phase sigma transcription factor. (+info)Polyphenols from alcoholic apple cider are absorbed, metabolized and excreted by humans. (5/489)
We determined the uptake and excretion of low doses of polyphenols in six subjects who each consumed 1.1 L of an alcoholic cider beverage. Over a 24-h period, no phloretin was detected in plasma (detection limit = 0.036 micromol/L), but 21 +/- 5% of the dose (4.8 mg) was excreted in the urine. In contrast, from a low dose of 1.6-mg quercetin equivalents, no quercetin was found in urine or plasma, but 3'-methyl quercetin was detected in plasma [C(max) (maximum concentration) = 0.14 +/- 0.19 micromol/L; range: 0 to 0.44 micromol/L]. No flavanol monomers (dose of free (+)-catechin and (-)-epicatechin = 3.5 mg) were detected in urine or plasma (detection limit: 0.01 micromol/L). Caffeic acid (total dose including esters = 11 mg) was detected only in plasma within 2 h, with C(max) = 0.43 +/- 0.3 micromol/L (range: 0.18 to 0.84 micromol/L). An almost 3-fold increase in hippuric acid was detected in 24-h urine (74 +/- 29 micromol/L; range: 38-116 micromol/L), compared with a prestudy value of 19 +/- 9 micromol/L. These data show that polyphenols are taken up from cider, that phloretin is excreted in the urine and suggest that low doses of quercetin are extensively methylated in humans. (+info)Cloning and characterization of four apple MADS box genes isolated from vegetative tissue. (6/489)
With the aim of finding genes involved in the floral transition of woody species four MADS box genes containing cDNAs from apple (Malus domestica) have been isolated. Three genes were isolated from vegetative tissue of apple, but were homologues of known genes that specify floral organ identity. MdMADS13 is an AP3-like B class MADS box gene, and was mainly expressed in petals and stamens as demonstrated by Northern blot analysis. MdMADS14 and -15 are AGAMOUS-like genes. They differed slightly in expression patterns on Northern blots, with MdMADS15 mRNA levels equally high in stamens and carpels, but MdMADS14 preferably expressed in carpels. MdMADS14 is likely to be the apple orthologue of one of the Arabidopsis thaliana SHATTERPROOF genes, and MdMADS15 closely resembled the Arabidopsis AGAMOUS gene. It has been shown with RT-PCR that the three floral apple MADS box genes are expressed in vegetative tissues of adult as well as juvenile trees, albeit at low levels. MdMADS12 is an AP1-like gene that is expressed at similar levels in leaves, vegetative shoots, and floral tissues, and that may be involved in the transition from the juvenile to the adult stage. (+info)Overexpression of polygalacturonase in transgenic apple trees leads to a range of novel phenotypes involving changes in cell adhesion. (7/489)
Polygalacturonases (PGs) cleave runs of unesterified GalUA that form homogalacturonan regions along the backbone of pectin. Homogalacturonan-rich pectin is commonly found in the middle lamella region of the wall where two adjacent cells abut and its integrity is important for cell adhesion. Transgenic apple (Malus domestica Borkh. cv Royal Gala) trees were produced that contained additional copies of a fruit-specific apple PG gene under a constitutive promoter. In contrast to previous studies in transgenic tobacco (Nicotiana tabacum) where PG overexpression had no effect on the plant (K.W. Osteryoung, K. Toenjes, B. Hall, V. Winkler, A.B. Bennett [1990] Plant Cell 2: 1239-1248), PG overexpression in transgenic apple led to a range of novel phenotypes. These phenotypes included silvery colored leaves and premature leaf shedding due to reduced cell adhesion in leaf abscission zones. Mature leaves had malformed and malfunctioning stomata that perturbed water relations and contributed to a brittle leaf phenotype. Chemical and ultrastructural analyses were used to relate the phenotypic changes to pectin changes in the leaf cell walls. The modification of apple trees by a single PG gene has offered a new and unexpected perspective on the role of pectin and cell wall adhesion in leaf morphology and stomatal development. (+info)Lyophilized apple counteracts the development of hypercholesterolemia, oxidative stress, and renal dysfunction in obese Zucker rats. (8/489)
Apples may have selective effects on abnormalities associated with the plurimetabolic syndrome. Therefore, the effects of 20% lyophilized apple supplementation on plasma and tissue lipids and on protection against susceptibility to oxidative stress and renal dysfunction were investigated in Zucker lean (Fa/-) or obese (fa/fa) rats. The experimental diets were equilibrated for sugar supply, contained 0.25 g/100 g cholesterol and provided only one third of the vitamin E requirement. Obese Zucker rats were hypercholesterolemic with cholesterol accumulation in LDL and HDL fractions. The apple diet lowered plasma and LDL cholesterol (-22 and -70%, respectively, P < 0.01) in obese Zucker rats and, in parallel, reduced triglyceride accumulation in heart and liver. Zucker rats fed the apple diet also had a larger intestinal pool and greater fecal excretion of bile acids. The heart concentration and urinary excretion of malondialdehyde were reduced by apple consumption in obese Zucker rats, suggesting better protection against peroxidation. Glucosuria and proteinuria in obese Zucker rats were also suppressed by the apple diet. In conclusion, despite their moderate fiber content, apples improve substantially the lipid status and peroxidative parameters in obese Zucker rats, suggesting that other plant constituents such as polyphenols are involved in these effects. (+info)I'm sorry for any confusion, but "Malus" is not a medical term. It is a genus name in the plant kingdom, referring to the apple tree. If you have a different term or concept in mind, please provide it so I can give you an accurate definition or explanation.
I apologize for any confusion, but "Rosales" is not a medical term. It is a botanical term used in the classification of plants. Rosales is an order of flowering plants that includes roses, as well as many other plants such as apples, cherries, almonds, and strawberries. The plants in this group are characterized by having flowers with multiple stamens and styles. I hope this clarifies any confusion. If you have any medical terms you would like defined, please let me know!
I'm sorry for any confusion, but "fruit" is not a medical term per se. It is a common term used to describe the part of a plant that develops from the ovary after flowering and contains seeds. However, in a nutritional or dietary context, "fruits" are often referred to as foods that are typically sweet and juicy, and come from plants' flowers. They are rich in fiber, vitamins, and minerals, making them an essential part of a healthy diet. But in a strict medical sense, there isn't a specific definition for "fruit."
"Pyrus" is the genus name for the fruit tree species that includes pears. It is not a medical term, but a taxonomic category in biology. The fruits produced by these trees are commonly consumed and can have various health benefits, but "Pyrus" itself does not have a specific medical definition.
'Erwinia amylovora' is a species of gram-negative, facultatively anaerobic bacteria that is a plant pathogen and the causative agent of fire blight, a destructive disease affecting members of the Rosaceae family, including apple and pear trees. The bacteria are capable of producing various virulence factors, such as cell wall-degrading enzymes and toxins, which contribute to their ability to cause disease in plants.
The bacteria typically enter the plant through wounds or natural openings, such as flowers, and then spread through the vascular system, causing wilting, discoloration, and death of infected tissues. In severe cases, fire blight can lead to the death of entire trees or orchards. The disease is difficult to control once it becomes established in an area, and management strategies typically involve a combination of cultural practices, such as pruning and sanitation, and the use of protective chemicals.
In addition to its economic impact on agriculture, 'Erwinia amylovora' has also been studied as a model organism for understanding plant-pathogen interactions and the mechanisms of bacterial pathogenesis.
Rosaceae is not a medical term but a taxonomic category in biology, specifically an family of flowering plants. However, many physicians and dermatologists are familiar with some members of this family because they cause several common skin conditions.
Rosaceae refers to a family of plants that include roses, strawberries, blackberries, and many other ornamental and edible plants. Some genera within this family contain species known to cause various dermatologic conditions in humans, particularly affecting the face.
The most well-known skin disorders associated with Rosaceae are:
1. Acne rosacea (or rosacea): A chronic inflammatory skin condition primarily affecting the central face, characterized by flushing, persistent erythema (redness), telangiectasia (dilated blood vessels), papules, pustules, and sometimes rhinophyma (enlarged, bulbous nose).
2. Erythematotelangiectatic rosacea: A subtype of rosacea characterized by persistent central facial erythema, flushing, and telangiectasia without papules or pustules.
3. Phymatous rosacea: A subtype of rosacea characterized by thickening skin, irregular surface nodularities, and enlargement, particularly of the nose (rhinophyma).
4. Ocular rosacea: Inflammation of the eyes and eyelids associated with rosacea, causing symptoms like dryness, grittiness, foreign body sensation, burning, stinging, itching, watering, redness, and occasional blurry vision.
While not a medical term itself, Rosaceae is an essential concept in dermatology due to the skin conditions it encompasses.
I'm sorry for any confusion, but the term "germ cells" is typically used in the context of animals and humans, referring to the reproductive cells (sperm and eggs) that can give rise to new individuals. It is not commonly used to describe plants.
In plants, the terms often used to refer to the reproductive cells are "male gametophyte" and "female gametophyte." The male gametophyte produces sperm cells, while the female gametophyte produces egg cells. These gametophytes are found within the pollen grains (male) and ovules (female) of plants.
Therefore, there isn't a medical definition for "germ cells, plant," as the term is not applicable in this context.
"Prunus" is a term that refers to a genus of plants, which includes many familiar fruits such as plums, cherries, peaches, and almonds. It's not a medical term, but rather a botanical one. The fruit of these plants are often used in food medicine due to their nutritional value and health benefits. For example, prunes (dried plums) are known for their laxative effects. However, the plant itself or its extracts can also have medicinal uses, mainly as anti-inflammatory, antioxidant and cardioprotective agents.
"Fragaria" is the genus name for plants in the family Rosaceae, which includes various species of strawberries. These plants are native to temperate regions of the world and are widely cultivated for their edible fruits. The term "Fragaria" itself does not have a specific medical definition, but certain compounds found in strawberries, such as flavonoids and vitamin C, have been studied for potential health benefits.
A medical definition for "plant shoots" may not be readily available, as the term is primarily used in botany and horticulture. However, I can provide you with a general definition:
Plant shoots refer to the above-ground portion of a plant, which typically includes structures like stems, leaves, flowers, and buds. Shoots originate from the seed or the growing tip of the plant and are responsible for photosynthesis, nutrient absorption, and reproduction. In some contexts, "plant shoots" might also refer to new growth that emerges from an existing plant, such as when a leaf or stem sprouts a new branch or flower.
Gene expression regulation in plants refers to the processes that control the production of proteins and RNA from the genes present in the plant's DNA. This regulation is crucial for normal growth, development, and response to environmental stimuli in plants. It can occur at various levels, including transcription (the first step in gene expression, where the DNA sequence is copied into RNA), RNA processing (such as alternative splicing, which generates different mRNA molecules from a single gene), translation (where the information in the mRNA is used to produce a protein), and post-translational modification (where proteins are chemically modified after they have been synthesized).
In plants, gene expression regulation can be influenced by various factors such as hormones, light, temperature, and stress. Plants use complex networks of transcription factors, chromatin remodeling complexes, and small RNAs to regulate gene expression in response to these signals. Understanding the mechanisms of gene expression regulation in plants is important for basic research, as well as for developing crops with improved traits such as increased yield, stress tolerance, and disease resistance.
"Plant proteins" refer to the proteins that are derived from plant sources. These can include proteins from legumes such as beans, lentils, and peas, as well as proteins from grains like wheat, rice, and corn. Other sources of plant proteins include nuts, seeds, and vegetables.
Plant proteins are made up of individual amino acids, which are the building blocks of protein. While animal-based proteins typically contain all of the essential amino acids that the body needs to function properly, many plant-based proteins may be lacking in one or more of these essential amino acids. However, by consuming a variety of plant-based foods throughout the day, it is possible to get all of the essential amino acids that the body needs from plant sources alone.
Plant proteins are often lower in calories and saturated fat than animal proteins, making them a popular choice for those following a vegetarian or vegan diet, as well as those looking to maintain a healthy weight or reduce their risk of chronic diseases such as heart disease and cancer. Additionally, plant proteins have been shown to have a number of health benefits, including improving gut health, reducing inflammation, and supporting muscle growth and repair.