Characterization of LYM genes in Medicago truncatula. M. truncatula contains a large family of genes encoding LysM-domain containing receptor-like proteins (Arrighi et al., 2006). In addition, several proteins containing single or multiple LysM domains can be predicted from available sequencing resources. Among these, two transcripts encoding proteins with structural homology to the chitin elicitor-binding protein CEBiP from rice (Oryza sativa (Kaku et al., 2006)) were identified, MtLYM1 and MtLYM2 (Arrighi et al., 2006). The proteins deduced from these transcripts featured signal peptides, indicating an extracellular localization (Fig. 1). Moreover, both proteins were predicted to be modified by glycosylphosphatidylinositol (GPI) for anchorage at the cell surface after removal of the C-terminal transmembrane domain. The genes encoding MtLYM1 and 2 contained five exons/four introns and four exons/three introns, respectively (Fig. 1), from which only one intron position was conserved between both genes. Interestingly, a small intron was present in MtLYM2 inside of the region encoding the three LysM domains, which was never observed for other genes encoding LysM-containing proteins in M. truncatula (Arrighi et al., 2006) We analyzed the phylogeny of LYMs by performing a consensus search of fully sequenced plant genomes for encoded proteins with similarity to LYMs from M. truncatula. Proteins, which were not predicted to contain a signal peptide or which were shorter than 300 residues were removed to obtain a list of 53 LYMs (suppl Table xx). In contrast to LYPs, which are defined, less stringently, as LysM-containing extracellular proteins and were detected in the moss Physcomitrella patens (Zhang et al., 2009), LYMs are present ... ... middle of paper ... ...n). Strongest promoter activity was observed in root tips and in lateral root emergences (Fig. 7A-D). Expression level and distribution was rather variable, with occasional staining of root hairs (Fig. 7A, D, F). During infection with Sinorhizobium meliloti (pXLGD4), GUS activity was detectable in developing nodules (Fig. 7E, F). Major nodules showed little GUS activity in the outer layers (Fig. 7G, H). Sectioning of old nodules (4 weeks pi ??) prior to GUS staining uncovered a peculiar expression pattern of MtLYM2. Here, promoter activity showed to be restricted to vascular bundles only, with, in some cases, very little staining of the outer cortex (Fig. 7x). In summary, the histochemical localization of GUS activity in proLYM2::GUS-int expressing roots and nodules confirmed our earlier observation of reduced transcript and protein levels in nodules versus roots.
Charles Darwin once compared the root tips of plants to “the brain of one of the lower animals” he even reported electrical signal systems in plants, much like a nervous system. More than a century after Darwin, a scientist named Mancuso discovered the center for the electrical signals, or action potentials, is located in the root tips. Even small plants had nearly 14 million root tips, all acting in a similar way to a nervous system. Humans and most animals have centralized brains, meaning it is all grouped together in one spot, forming what we envision as a brain. Plants may not have a centralized brain like humans, but that doesn’t mean they lack a brain, in fact plants have “decentralized intelligence” distributed throughout them. Since plants cannot react quickly, they have no way of defending themselves against predators, so by scattering the “brain” plants avoid dying off when damaged (Marinelli). The root tips and sensory cells allow plants to feel and react to different stimuli. It is uncertain as to whether plants feel pain, but they do respond to anesthetics and react to being damaged. For example, when a caterpillar eats a plant’s leaf, the plant begins to secrete defensive chemicals. The censor cells react to the damage being done and cause the leaf to secrete chemicals to fend off the predator, as well as repair the
Mat Johnsons novel, Pym challenges readers not only to view his work with a new set of eyes but also the work of all American literature with the understanding that the idea of Whiteness still has a very strong power over literature today. It is unfortunate that in today’s society, the pathology of Whiteness still holds a very strong presence in literary world. Literature from American authors versus literature from African American authors still continues to be segregated and handled with two different sets of criteria. Johnson’s novel engages in different aspects of the argument presented in Toni Morrison’s work entitled Playing in the Dark: Whiteness and the Literary Imagination. One of the main ideals that Pym engages in is the thought that “…a figuration of impenetrable whiteness … surfaces in American literature whenever Africanist presence is engaged” (29). Through the character Chris Jaynes, Johnson’s novel focuses much attention on the Whiteness seen in the literary world and how it still affects literature today. Mat Johnson’s Pym addresses Morrison’s argument by challenging the reader to identify the pathology of whiteness as well as encourages readers not to only identify the problem but try to find new ways to combat it.
...e involved in the plants carbohydrate metabolism. This response causes the plant’s cell walls to be rearranged and strengthened. THis would increase the plants resistance to infection and the uptake of harmful chemicals.
Phosphorylation and dephosphorylation can activate or deactivate a protein but changing in 3-D conformation and as a result changing the ability to interact with other proteins. Just like in Arabidopsis and other an...
(ii) Motility and chemotaxis. In addition to their role in the attachment of microorganisms to plant roots, functional flagella are important for bacterial motility. The crucial role of motility for successful rhizosphere colonization is somewhat controversial because some studies have indicated that motility of Pseudomonas is not required for root colonization in wheat and soybean (Howie et al. 1987). However, flagella were shown to be essential for colonization of potato roots (de Weger et al. 1987). Studies confirming the role of motility in the colonization process were performed in the absence of percolating water, and it was assumed that motile or non-motile introduced bacterial strains were transported by the growing roots. However, under more natural conditions the presence of percolating water will affect the dispersal of bacterial strains regardless of their ability to swim.
“Molecular and Cellular Cloning - Boundless Open Textbook." Boundless. Boundless, n.d. Web. aaaaa 22 May 2014.
Schumann, Gail L., and Cleora J. D'Arcy. Hungry Planet: Stories of Plant Diseases. St. Paul: American Phytopathological Society, 2012. Print.
In plant and animal cells there are particular signals that trigger the release of proteins or other regulatory molecules in order to adjust and maintain homeostasis. Not very many molecules can enter, leave, or cross organelle membranes by themselves. Most molecules require the use of transport proteins. Transporter proteins can only bind to very few substrates at a time and undergoes a conformational change so that only these may be transported across the membrane. In order for cell to have normal growth and development cell signaling is a necessity. When a signal molecule binds to a cell surface receptor protein, it activates and releases a G protein on the inside of the cell. The G protein then stimulates adenylyl cyclase to produce large amounts of cyclic AMP with the cell.
Cain, M. L., Urry, L. A., & Reece, J. B. (2010). Campbell Biology. Benjamin Cummings.
Plant defences are those mechanisms employed by plants in response to herbivory and parasitism. According to Hanley et al. (2007), “the tissues of virtually all terrestrial, freshwater, and marine plants have qualities that to some degree reduce herbivory, including low nitrogen concentration, low moisture content, toxins or digestibility-reducing compounds”. The type of chemical defence may be species specific (Scott 2008). The defences that plants possess may be in the form of chemical production or in the form of physical defences such as thorns or spikes and even through reinforced, rigid leaves. “The compounds that are produced in response to herbivory can either have a direct effect on the attacker itself (e.g. toxins or digestibility reducers), or serve as indirect defenses by attracting the natural enemies of the herbivores” (Bezemer & van Dam 2005). This essay will focus on chemical plant defences and in particular the effects of terpenes, phenolics, nitrogen-based defences as well as allelopathy in plants.
2)Campbell, Neil A., and Jane B. Reece. Biology. San Francisco, CA: Benjamin Cummings, 2008. Print.
Raven, P. H., Mason, K. A., Losos, J. B., Singer, S. R., & Johnson, G. B. (2011). Biology (9thth ed., pp. 418-419). New York City, NY: McGraw Hill.
Campbell, N. A. & J. B. Reece, 8th eds. (2008). Biology. San Francisco: Pearson Benjamin Cummings.
J. Losos, K. Mason, S. Singer, based on the work of P. Raven, & G. Johnson, Biology, 8th ed., (McGraw-Hill Education (Asia), Singapore, 2008), pp. 994-995.