70 research outputs found

    Investigation of Growth Rate and Phycocolloid Content from Kappaphycus alvarezii (Rhodophyta, Solieriaceae) under Different Light Conditions Using Vibrational Spectroscopy

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    Kappa-carrageenan (K-carrageenan) is an important phycocolloid which is a major constituent of the cell wall of Kappaphycus alvarezii. The chemical structure of K-carrageenan comprises a linear backbone of D-galactose residues linked with alternating α-(1,3) and β-(1,4) linkages which are substituted by one ester-sulphonic group per di-galactose repeating unit. The spectral qualities of light as well as the ambient carbon dioxide concentration, both play an important role in the photosynthetic pathway in plants and this investigation set forth to establish the effect of different wavelengths of light and carbon dioxide supplementation on the chemical structure of K-carrageenan obtained from K. alvarezii. Specimens were cultivated under a range of monochromatic light spectra and assessed for chemical composition using Fourier Transform Infrared (FTIR) spectroscopy.The K. alvarezii control was irradiated with full light spectrum, treatments were carried out using blue (492-455 nm), green (577-492 nm) and red (780-622 nm)light. One experiment was carried out by supplementation with carbon dioxide. Samples were collected after 14 days. The effect of different wavelengths of light on the growth rates of experimental samples was determined. Red light had the most significant impact on the growth rate of K. alvarezii as compared to those treated with blue light. The FTIR fingerprint of the ground seaweed was found to be identical to that of commercial K-carrageenan (Sigma). Special emphasis was given to the 800-1300 cm-1 region, which presents several vibrational modes. All the samples produced similar FTIR spectral profiles, suggesting that genes related to the carrageenan biosynthesis are not affected by different wavelengths of light or CO2. The results obtained from FTIR spectroscopy demonstrated that different wavelengths of light and supplementation with CO2 have no influence to the chemical structure of K-carrageenan in K. alvarezii

    A Brief Overview of the NEBULA Future Internet Architecture

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    NEBULA is a proposal for a Future Internet Architecture. It is based on the assumptions that: (1) cloud computing will comprise an increasing fraction of the application workload offered to an Internet, and (2) that access to cloud computing resources will demand new architectural features from a network. Features that we have identified include dependability, security, flexibility and extensibility, the entirety of which constitute resilience.NEBULA provides resilient networking services using ultrareliable routers, an extensible control plane and use of multiple paths upon which arbitrary policies may be enforced. We report on a prototype system, Zodiac, that incorporates these latter two features

    CDNF rescues motor neurons in models of amyotrophic lateral sclerosis by targeting endoplasmic reticulum stress.

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    Amyotrophic lateral sclerosis is a progressive neurodegenerative disease that affects motor neurons (MNs) in the spinal cord, brainstem, and motor cortex, leading to paralysis and eventually to death within 3 to 5 years of symptom onset. To date, no cure or effective therapy is available. The role of chronic endoplasmic reticulum (ER) stress in the pathophysiology of amyotrophic lateral sclerosis, as well as a potential drug target, has received increasing attention. Here, we investigated the mode of action and therapeutic effect of the ER-resident protein cerebral dopamine neurotrophic factor (CDNF) in three preclinical models of amyotrophic lateral sclerosis, exhibiting different disease development and etiology: (i) the conditional choline acetyltransferase (ChAT)-tTA/TRE-hTDP43-M337V rat model previously described, (ii) the widely used SOD1-G93A mouse model, and (iii) a novel slow-progressive TDP43-M337V mouse model. To specifically analyse the ER stress response in MNs, we used three main methods: (i) primary culture of MNs derived from E13 days embryos, (ii) immunohistochemical analyses of spinal cord sections with ChAT as spinal MNs marker, and (iii) qPCR analyses of lumbar MNs isolated via laser microdissection. We show that intracerebroventricular administration of CDNF significantly halts the progression of the disease and improves motor behavior in TDP43-M337V and SOD1-G93A rodent models of amyotrophic lateral sclerosis. CDNF rescues motor neurons in vitro and in vivo from ER stress-associated cell death and its beneficial effect is independent of genetic disease etiology. Notably, CDNF regulates the unfolded protein response (UPR) initiated by transducers IRE1α, PERK, and ATF6, thereby enhancing MN survival. Thus, CDNF holds great promise for the design of new rational treatments for amyotrophic lateral sclerosis

    What the disjunctivist is right about

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    There is a traditional conception of sensory experience on which the experiences one has looking at, say, a cat could be had by someone merely hallucinating a cat. Disjunctivists take issue with this conception on the grounds that it does not enable us to understand how perceptual knowledge is possible. In particular, they think, it does not explain how it can be that experiences gained in perception enable us to be in ‘cognitive contact’ with objects and facts. I develop this chal- lenge to the traditional conception and then show that it is possible to accommo- date an adequate account of cognitive contact in keeping with the traditional conception. One upshot of the discussion is that experiences do not bear the explanatory burden placed upon them by disjunctivists
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