Saps/exudates And Their Collection
Much of our knowledge of what is found in and translocated by phloem comes from analyses of sieve tube exudate and in xylem by analyses of sap, displaced from the vasculature by applying either increased or decreased pressure. A range of techniques has been developed and exploited to sample transport fluids and it is appropriate to consider the likely limitations that collection methods impose on interpretation of the compositional data they have generated.
The issue of purity of phloem exudate has been addressed by a number of groups. compared the two-dimensional protein profile of B. napus phloem exudate with that of adjacent stem tissue and found that there was very little overlap in spot pattern between the two samples. Other groups have tested for proteins or mRNAs that would be expected in stem tissue but not phloem. Most commonly used is Rubisco or the transcript for its small subunit and these assays suggest that there is limited contamination from outside cells .
While these considerations will not have a significant impact on the nature and form of the major solutes in phloem and xylem they are likely to be important for minor constituents and especially on the macromolecules that have been found in exudates or saps and for which long distance signaling roles have been postulated, based on their assumed translocation. Confirming the constituents identified in phloem exudate move across a graft union becomes an important criterion to prove translocation.
Aml With Recurrent Chromosomal Translocation Abnormalities
Chromosome translocations in AML most often result in juxtaposition of one genetic locus with another unrelated gene, leading to the formation of a fusion proto-oncogene and transcription of a chimeric mRNA species that retains partially functional but aberrantly regulated features of both individual genes. Leukemogenic gene fusions frequently involve at least one partner gene with a critical transcriptional role in normal hematopoiesis the resulting altered chimeric protein therefore manifests widespread pathophysiologic effects on cell differentiation, maturation, and apoptosis in the AML stem or progenitor cells. Although chromosomal translocations can be detected by conventional cytogenetic and FISH techniques, RT-PCR methods with primers spanning breakpoint-fusion regions are also commonly used to sensitively and specifically identify the resulting novel chimeric mRNA products at diagnosis in some subtypes of AML . Leukemia-specific transcripts also serve as invaluable markers for detecting minimal residual disease using RQ-PCR methods in patients who have received curative-intent therapy.
Roberto Chiarle, in, 2013
How Does Glucose Move From The Leaves To The Phloem
Glucose made in the leaves through photosynthesis is then moved to all cells in phloem vessels by translocation. When the plant opens its stomata to let in carbon dioxide, water on the surface of the cells of the spongy mesophyll and palisade mesophyllevaporates and diffuses out of the leaf. This process is called transpiration.
Protein Factors Used In Translation
They are also called translational factors.
There are three types of these
There are three types of these
IF-1 It helps in the binding of IF-3.
IF-2 It combines GTP and tRNA with the 30S subunit.
IF-3 It connects to the 30S subunit and prevents prematurely adding the 50S subunit.
What Is Robertsonian Translocation Give Example
A Robertsonian translocation results when the long arms of two acrocentric chromosomes fuse at the centromere and the two short arms are lost. If, for example, the long arms of chromosomes 13 and 14 fuse, no significant genetic material is lostâand the person is completely normal in spite of the translocation.
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What Is The Use Of Translocation
Translocation as a tool is used to reduce the risk of a catastrophe to a species with a single population, to improve genetic heterogeneity of separated populations of a species, to aid the natural recovery of a species or re-establish a species where barriers might prevent it from doing so naturally.
Oncogenic Translocations In Cancer Frequently Have Dsb Intermediates
Chromosomal translocations are fundamental pathogenetic events in cancer, both with respect to tumor onset and tumor progression. Recurrent oncogenic translocations are common features of hematopoietic malignancies such as leukemia and lymphomas . Likewise, genomic instability in the form of translocations and related deletions and amplifications occurs in the context of solid tumor progression. Solid tumors, such as certain brain tumors, as well as prostate and lung cancers, also can contain recurrent translocations . Indeed, a major goal of the large cancer genome project is to better define genomic alterations in tumor cells, including translocations, deletions, inversions, and amplifications. DSBs are common intermediates in such genomic aberrations. DSBs can be generated by normal metabolic processes, by genotoxic agents including agents commonly used to treat cancer, and by the programmed processes of VJ recombination and immunoglobulin heavy chain class switch recombination in T and/or B lymphocytes. When DSBs occur, highly conserved DNA repair pathways efficiently rejoin broken ends to preserve the genome integrity. Nonetheless, repair sometimes fails, and the resulting unresolved DSBs can lead to chromosomal translocations and other genomic aberrations.
Moshe E. Gatt, … Shai Izraeli, in, 2013
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Latest Research And Reviews
Chowdhury, Sau and Musser report a multicolour imaging approach that enables the 3D visualization of cargo transport trajectories relative to a super-resolved nuclear pore complex scaffold in non-fixed permeabilized cells.
- Rajdeep Chowdhury
A new version of SignalP predicts all types of signal peptides.
What Is Translocation In Down Syndrome
Translocation Down syndrome refers to the rearranged chromosome material. There are three # 21 chromosomes, just like there are in trisomy 21, but one of the 21 chromosomes is attached to another chromosome, instead of being separate. The extra # 21 chromosome is what causes the problems that make up Down syndrome.
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What Is Group Translocation
What is group translocation microbiology quizlet?, Group Translocation. Active transport: Compound being moved across the inner membrane is chemically modified. Phosphotransferase System. removes phosphate group from PEP and adds it to glucose
Furthermore, What is group translocation in biology?, Definition. noun. A mechanism utilized by bacteria to transport a compound into their cell by first allowing the compound to bind with protein on the cell surface followed by altering its chemical structure during its passage across the membrane.
Finally, Which of the following is an example of group translocation?, An example of group translocation in bacteria is the phosphotransferase system. A high-energy phosphate group from phosphoenolpyruvate is transferred by a series of enzymes to glucose. The final enzyme both phosphorylates the glucose and transports it across the membrane as glucose 6-phosphate.
How Do You Know If Translocation Is Balanced
Sometimes a section from one chromosome of a particular pair changes places with a section from a chromosome of another pair. When the two breaks do not pass through a gene and there is no gain or loss of material when the chromosomes are looked at under a microscope, it is called a balanced translocation.
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Structure Of Phloem Cells
The translocation of molecules via the phloem pathway is dependent on the functioning of specialized cells that are distributed in an organized manner throughout the plant. The cells that conduct nutrients over long distances are called sieve elements, of which there are two types: sieve cells, which are found in gymnosperms , and sieve-tube members, which are found in angiosperms . Sieve elements are narrow, elongated cells that are aligned in long columns that extend from source to sink regions within the plant. Sieve elements are living cells and thus possess a plasma membrane at their periphery, just inside the cell wall. However, they do not contain a nucleus at full maturity, and possess only a few cellular organelles . The lack of a nucleus and most other cellular structures means that the cell interior is rather open. This serves to make sieve elements good conduits for long-distance solution flow.
Accessory cells are also found associated with the sieve cells of gymnosperms, where they are called albuminous cells. The albuminous cells are structurally comparable to and perform a role similar to that of companion cells.
Water Uptake And Transport Across The Root
Root hairs are single-celled extensions of epidermal cells in the root. They grow between soil particles and absorb water and minerals from the soil.
Water enters the root hair cells by osmosis. This happens because soil water has a higher concentration of water molecules than the cytoplasm of the root hair cell. Minerals enter by active transport.
A summary of water uptake, water transport and transpiration:
Why Are Translocation Heterozygotes Often Sterile
Translocation heterozygotes generally display 50% pollen sterility in plants because alternate and adjacent-1 distributions occur at about equal frequency in the absence of crossing over adjacent-2 distributions, being non-disjunctional, are very rare. Recombination in translocation homozygotes may be normal.
Mapping Protein Interactions In The Active Tom
The TOM and TIM23 complexes facilitate the transport of nuclear-encoded proteins into the mitochondrial matrix. Here, the authors use a stalled client protein to purify the translocation supercomplex and gain insight into the TOM-TIM23 interface and the mechanism of protein handover from the TOM to the TIM23 complex.
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Chromosomal Abnormalities Other Than Chromosomal Translocations
Although less frequent and generally less amenable to purely molecular diagnostic techniques, recurrent chromosomal abnormalities other than translocations contribute to the malignant phenotype of various tumors and can be useful diagnostic markers. Chromosomal inversions involve breakage within a segment of a chromosome, with a 180-degree rearrangement so that there is a reversal in the orientation of the chromosome segment. These segments may represent any portion of a chromosomal arm, such as the inversion on the short arm of chromosome 2 that leads toALK rearrangements in lung adenocarcinoma,36 or they may be pericentric, with breakpoints on either side of the centromere, as in the inv16 of acute myelomonocytic leukemia with eosinophilia.37 Inversions are functionally similar to translocations in that alterations affect the structure or activity of genes near one or other breakpoint.
Chromosomal deletions can result from the loss of a whole chromosome, leaving only one homolog loss of whole chromosomal arms or loss of interstitial segments of a chromosomal arm, as in the 5q syndrome associated with myelodysplasia. Deletions often have variable breakpoints and usually result in the oncogenic consequences of losing a tumor suppressor gene within the deleted segment.
Duplications of whole chromosomes 38 or intrachromosomal duplications of various regions 39 are also characteristic of certain tumors.
Moshe E. Gatt, Shai Izraeli, in, 2019
Preparing For Translocations Of A Critically Endangered Petrel Through Targeted Monitoring Of Nest Survival And Breeding Biology
Published online by Cambridge University Press: 29 April 2021
- School of Biological Sciences, Victoria University of Wellington, PO Box 600, Wellington, 6140, New Zealand
- Heiko U. Wittmer
- School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand
- Graeme A. Taylor
- Aquatic Unit, Department of Conservation, Wellington, New Zealand
- Igor Debski
- Aquatic Unit, Department of Conservation, Wellington, New Zealand
- Doug P. Armstrong
- Wildlife Ecology Group, Massey University, Palmerston North, New Zealand
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What Is Translocation A Level Biology
Translocation is the movement of dissolved substances, such as sucrose and amino acids, from parts of the plant where the substances are made to other parts of the plant where theyre needed. This maintains a concentration gradient between the source and the sink, so that more sucrose moves into the source.
Long Distance Signaling In Legumes
Legumes provide an opportunity to study two phenomena involving long distance signaling: autoregulation of nodule development and cluster root formation. When nodule development is initiated there is an exchange of signals between the roots and shoot to regulate the number of nodules that develop. This signaling also appears to be related to one of the mechanisms by which legumes regulate the symbiosis in response to soil nitrogen conditions. Split root experiments, where one part of a root system was inoculated with rhizobia and subsequently inhibited nodulation on the other part, suggested that the signal was systemic. A number of mutants, super- or hypernodulators have been identified where this control is lost . Grafting experiments with some of these mutants showed that the shoot genotype controls nodule development. A signal derived in the roots is translocated and perceived in the shoot generating a second signal that inhibits further development of nodule primordia. Although the genes above have now been cloned and shown to encode a Leu-rich repeat receptor-like kinase similar to CLAVATA1 from Arabidopsis , the nature of the signal molecules involved have not been defined .
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What Is Lymph 10 Cbse
Lymph is another fluid involved in transportation. Lymph drains into lymphatic capillaries which join to form large lymph vessels and which open into larger veins. Function of lymph is to carry absorbed digested fat from intestine and it also drains excess fluid from extra cellular space back into the blood.
Loading And Unloading Of Sugars And The Pressure
With the presence of a continuous, membrane-bound pathway, phloem sap can flow from source to sink regions within the plant. But how do the components of the phloem sap get in to or out of the pathway, and what is the mechanism, or driving force, that moves the solution? As noted earlier, the predominant solute in phloem sap is sugar, and in many species the translocated sugar is sucrose. For these species, sucrose is manufactured primarily in the photosynthetic mesophyll cells of the leaf, from where it must be transported to the minor veins of the phloem system. Sucrose can move to the minor veins using an intracellular pathway, referred to as symplastic movement, or it can diffuse through a path along the cell walls, a process known as apoplastic movement. In either case, sucrose is eventually pumped into sieve elements through an active, energy-requiring process called phloem loading. The amino acids and mineral ions found in phloem sap also are said to be “phloem loaded.”
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What Is A Translocation
In biology, translocation refers to two completely different processes. In botany, or the study of plants, translocation is the movement of material from one place to another within a plant. In genetics, it is the exchange of parts between two chromosomes. In this article, we are going to be looking at chromosomal translocation specifically.
Within the nucleus of all cells, strands of DNA form chromosomes, which is where the genes are located. All cells of the body, except reproductive cells, have matching pairs of chromosomes, or homologous chromosomes. In homologous chromosomes, both chromosomes are the same size and shape and have the same genes in the same location. One of each pair comes from the mother and one from the father. Within the reproductive cells, or sex cells, only one copy of each chromosome occurs.
A translocation is a form of structural alteration that occurs between non-homologous chromosomes. It often occurs during meiosis when the chromosomes are close together. During a translocation, portions of non-homologous chromosomes break off from the original and are then interchanged. The result of a translocation is that the structure of the two chromosomes has now been changed.
Phloem Structure And Function
The tissue in which nutrients move is the phloem . The phloem is arranged in long, continuous strands called vascular bundles that extend through the roots and stem and reach into the leaves as veins. Vascular bundles also contain the xylem , the tissue that carries water and dissolved minerals from the roots to the shoots. When plants increase in diameter they do so by divisions of a layer of cells just under the bark this cell layer makes new xylem to the inside and a thin, continuous cylinder of new phloem to the outside.
The contents of the phloem can be analyzed by cutting off the stylets of phloem-feeding insects such as aphids and collecting the drops of sap that exude. Phloem sap is composed largely of sugar dissolved in water. All plants translocate sucrose and some also transport other sugars such as stachyose, or sugar alcohols such as sorbitol. Many other organic compounds are found, including amino acids , proteins , and . Glucose , the sugar found in the circulatory system of animals, is not translocated.
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How Does Translocation Cause Leukemia
Chromosome Translocations in Leukemia and Lymphomas A translocation is a type of abnormal change in the structure of a chromosome that occurs when a part of one chromosome breaks off and sticks to another chromosome. These âmutationsâ are an important cause of many types of lymphomas and leukemias.
Ways To Determine The Chemical Nature Of Phloem Sap And The Rate Of Translocation
Scientists have been interested in studying the composition of phloem sap for many years because of its importance to plant growth and development. Unfortunately, access to pure phloem sap is difficult for a number of reasons: sieve elements are very narrow cells , they are embedded within other tissues of the plant, and most plants have a sealing mechanism that prevents the loss of phloem sap upon cutting. Certain techniques do exist, however, that get around these problems. One approach involves the use of aphids, which are insects that feed selectively upon the contents of sieve elements but do not induce a sealing reaction. Scientists allow an aphid to insert its stylet, a long tube-shaped mouth part, into the side of a sieve element within a stem or leaf. The insect is then sacrificed and removed, with its stylet still inserted in the plant tissue, either by using a razor blade or a laser burst. Because the phloem sap is pressurized, phloem sap will flow out the cut end of the stylet for a short period of time and it can be collected for analysis. Standard analytical chemistrytechniques are then used to determine carbohydrate and mineral composition of the phloem sap, or more modern techniques of protein chemistry and molecular biology are used to quantify and characterize the protein and nucleic acid composition of the collected solution.
see also Leaves Photosynthesis, Carbon Fixation and Stems Vascular Tissues.
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