Businesses should hire employees for their entire lives. Do you agree or disagree? Use specific reasons and examples to support your answer. I would have to completely disagree with the statement above. In the following paragraphs I will outline the basic concepts of my position. First of all, I will least the major disadvantages for employers. On the today’s market a company must be very flexible in order to compete with other firms. So, imagine the situation when a company can not fire its employees to stay on the market. It will lead to loosing not only a profit, but the clients, market share and competitive ability. Now, imagine the situation when a company is growing fast, everything is good and the next few years are going to be excellent. So, employers need more people to extend the production. However, nobody can tell what will happen in a few years. In this case, employers will be afraid to hire new people and extend their business because they will not be able to fire them if something goes wrong. Another important aspect of this is that a company can not have the best employees. It can not hire the better one without dismissing another employee. What kind of disadvantages will have an employee in exchange for this kind of job security? First of all, it will be very difficult to find a job if one is not the best, because an employer does not want to spend money on one’s education. Besides, employer will not have a chance to fire one if he does not do his job well. Second of all, employees with this kind of security tend not to perfect themselves because after they are hired they can not lose their job. In conclusion, I would like to add that this statement has some positive aspects too such as constancy, a strong spirit of the company, etc. This system takes place in Japan and some companies succeeded in it. But I think that the reason of it subsists in the Japanese traditions, the particular cultural features, habits and customs. However, on today’s market here in the United States a company can not afford to hire employees for their entire life. Requirements for Human Life Requirements for Human Life Bởi: OpenStaxCollege Humans have been adapting to life on Earth for at least the past 200,000 years Earth and its atmosphere have provided us with air to breathe, water to drink, and food to eat, but these are not the only requirements for survival Although you may rarely think about it, you also cannot live outside of a certain range of temperature and pressure that the surface of our planet and its atmosphere provides The next sections explore these four requirements of life Oxygen Atmospheric air is only about 20 percent oxygen, but that oxygen is a key component of the chemical reactions that keep the body alive, including the reactions that produce ATP Brain cells are especially sensitive to lack of oxygen because of their requirement for a high-and-steady production of ATP Brain damage is likely within five minutes without oxygen, and death is likely within ten minutes Nutrients A nutrient is a substance in foods and beverages that is essential to human survival The three basic classes of nutrients are water, the energy-yielding and body-building nutrients, and the micronutrients (vitamins and minerals) The most critical nutrient is water Depending on the environmental temperature and our state of health, we may be able to survive for only a few days without water The body’s functional chemicals are dissolved and transported in water, and the chemical reactions of life take place in water Moreover, water is the largest component of cells, blood, and the fluid between cells, and water makes up about 70 percent of an adult’s body mass Water also helps regulate our internal temperature and cushions, protects, and lubricates joints and many other body structures The energy-yielding nutrients are primarily carbohydrates and lipids, while proteins mainly supply the amino acids that are the building blocks of the body itself You 1/7 Requirements for Human Life ingest these in plant and animal foods and beverages, and the digestive system breaks them down into molecules small enough to be absorbed The breakdown products of carbohydrates and lipids can then be used in the metabolic processes that convert them to ATP Although you might feel as if you are starving after missing a single meal, you can survive without consuming the energy-yielding nutrients for at least several weeks Water and the energy-yielding nutrients are also referred to as macronutrients because the body needs them in large amounts In contrast, micronutrients are vitamins and minerals These elements and compounds participate in many essential chemical reactions and processes, such nerve impulses, and some, such as calcium, also contribute to the body’s structure Your body can store some of the micronutrients in its tissues, and draw on those reserves if you fail to consume them in your diet for a few days or weeks Some others micronutrients, such as vitamin C and most of the B vitamins, are water-soluble and cannot be stored, so you need to consume them every day or two Narrow Range of Temperature You have probably seen news stories about athletes who died of heat stroke, or hikers who died of exposure to cold Such deaths occur because the chemical reactions upon which the body depends can only take place within a narrow range of body temperature, from just below to just above 37°C (98.6°F) When body temperature rises well above or drops well below normal, certain proteins (enzymes) that facilitate chemical reactions lose their normal structure and their ability to function and the chemical reactions of metabolism cannot proceed That said, the body can respond effectively to short-term exposure to heat ([link]) or cold One of the body’s responses to heat is, of course, sweating As sweat evaporates from skin, it removes some thermal energy from the body, cooling it Adequate water (from the extracellular fluid in the body) is necessary to produce sweat, so adequate fluid intake is essential to balance that loss during the sweat response Not surprisingly, the sweat response is much less effective in a humid environment because the air is already saturated with water Thus, the sweat on the skin’s surface is not able to evaporate, and internal body temperature can get dangerously high 2/7 Requirements for Human Life Extreme Heat Humans adapt to some degree to repeated exposure to high temperatures (credit: McKay Savage/flickr) The body can also respond effectively to short-term exposure to cold One response to cold is shivering, which is random muscle movement that generates heat Another response is increased breakdown of stored energy to generate heat When that energy reserve is depleted, however, and the core temperature begins to drop significantly, red blood cells will lose their ability to give up oxygen, denying the brain of this critical component of ATP production This lack of oxygen can cause confusion, lethargy, and eventually loss of consciousness and death The body responds to ... Structural requirements for the apical sorting of human multidrug resistance protein 2 (ABCC2) Anne T. Nies 1 ,Jo¨rg Ko¨ nig 1 , Yunhai Cui 1 , Manuela Brom 1 , Herbert Spring 2 and Dietrich Keppler 1 1 Division of Tumor Biochemistry, Deutsches Krebsforschungszentrum, Heidelberg, Germany; 2 Division of Cell Biology, Deutsches Krebsforschungszentrum, Heidelberg, Germany The human multidrug resistance p rotein 2 (MRP2, symbol ABCC2) is a polytopic membrane glycoprotein of 1545 amino acids which exports anionic conjugates across the apical membrane of polarized cells. A chimeric protein composed of C-proximal MRP2 and N-proximal MRP1 localized to the a pical membrane of polarized Madin–Darby canine kidney cells (MDCKII) indicating involvement of the carboxy-proximal part of human MRP2 in apical sorting. When compared to other MRP family members, MRP2 has a seven-amino-acid extension at its C-terminus with the last three amino acids (TKF) comprising a PDZ-interacting motif. In order to analyze whether this extension is required for apical sorting of MRP2, we g enerated MRP2 constructs mutated a nd stepwise truncated at their C-termini. T hese constructs were fused via their N-termini to green fluorescent protein ( GFP) and were transiently transfected into polar- ized, liver-derived hu man HepG2 cells. Q uantitative analysis showed th at full-length GFP– MRP2 was localized to the apical membrane in 73% of transfected, polarized cells, whereas it remained o n i ntracellular membranes in 27% of cells. Removal of the C-terminal TKF peptide a nd stepwise deletion of up to 11 amino acids did not change this pre- dominant apical d istribution. However, apical localization was largely impaired when GFP–MRP2 was C-terminally truncated by 15 or more amino acids. Thus, neither the PDZ-interacting TKF motif nor the full seven-amino-acid extension were necessary for apical sorting of MRP2. Instead, our d ata indicate that a d eletion of at least 15 C-terminal amino acids impairs the localiz ation o f MRP2 to the a pical membrane of polarized cells. Keywords: epithelial polarity; green fluorescent protein; multidrug r esistance protein 2; protein trafficking. Members of the multidrug resistance p rotein (MRP) f amily are i ntegral membrane glycoproteins which m ediate the ATP-dependent export of amphiphilic anions across the plasma membrane [1]. MRP1, t he first cloned member o f the MRP family [2], is present in the plasma membrane of several cell types [3–5]. After t ransfection of MRP1 cDNA in polarized cells, MRP1 is localized to the basolateral membrane [6]. Several M RP family members are known to be endogenously expressed in polarized cells. Whereas MRP3 [7,8] and MRP6 [9,10] are localized to the basolateral membrane of rat and human hepatocytes, MRP2 is the only isoform identified so far that is localized exclusively to the apical membrane of polarized cells, s uch as hepatocytes and renal proximal tubule cells [1,11,12]. MRP2 was initially cloned f rom rat liver [11,13,14], and subsequently from human liver [11,15,16] and human tumor cells [17]. Trans- port studies using inside-out oriented membrane vesicles from liver [18,19] or from cells stably transfected with human MRP2 cDNA [16,20,21] demonstrated the transport of conjugated and unconjugated lipophilic anions by MRP2. The absence of MRP2 from the canalicular membrane of human hepatocytes is the molecular basis of the Dubin–Johnson syndrome [ 15,22–24], which is associ- ated with conjugated hyperbilirubinemia. Epithelial cell BIOTECHNOLOGY - MOLECULAR STUDIES AND NOVEL APPLICATIONS FOR IMPROVED QUALITY OF HUMAN LIFE Edited by Reda Helmy Sammour Biotechnology - Molecular Studies and Novel Applications for Improved Quality of Human Life Edited by Reda Helmy Sammour Published by InTech Janeza Trdine 9, 51000 Rijeka, Croatia Copyright © 2012 InTech All chapters are Open Access distributed under the Creative Commons Attribution 3.0 license, which allows users to download, copy and build upon published articles even for commercial purposes, as long as the author and publisher are properly credited, which ensures maximum dissemination and a wider impact of our publications. After this work has been published by InTech, authors have the right to republish it, in whole or part, in any publication of which they are the author, and to make other personal use of the work. Any republication, referencing or personal use of the work must explicitly identify the original source. As for readers, this license allows users to download, copy and build upon published chapters even for commercial purposes, as long as the author and publisher are properly credited, which ensures maximum dissemination and a wider impact of our publications. Notice Statements and opinions expressed in the chapters are these of the individual contributors and not necessarily those of the editors or publisher. No responsibility is accepted for the accuracy of information contained in the published chapters. The publisher assumes no responsibility for any damage or injury to persons or property arising out of the use of any materials, instructions, methods or ideas contained in the book. Publishing Process Manager Ivana Zec Technical Editor Teodora Smiljanic Cover Designer InTech Design Team First published February, 2012 Printed in Croatia A free online edition of this book is available at www.intechopen.com Additional hard copies can be obtained from orders@intechweb.org Biotechnology - Molecular Studies and Novel Applications for Improved Quality of Human Life, Edited by Reda Helmy Sammour p. cm. ISBN 978-953-51-0151-2 Contents Preface IX Part 1 Molecular Studies 1 Chapter 1 The Effect of CLA on Obesity of Rats: Meta-Analysis 3 Sejeong Kook and Kiheon Choi Chapter 2 Ammonia Accumulation of Novel Nitrogen-Fixing Bacteria 13 Kenichi Iwata, San San Yu, Nik Noor Azlin binti Azlan and Toshio Omori Chapter 3 Bioactive Compounds from Bacteria Associated to Marine Algae 25 Irma Esthela Soria-Mercado, Luis Jesús Villarreal-Gómez, Graciela Guerra Rivas and Nahara E. Ayala Sánchez Chapter 4 The Welfare of Transgenic Farm Animals 45 Michael Greger Chapter 5 Establishment of Functional Biotechnology Laboratories in Developing Countries 65 Marian D. Quain, James Y. Asibuo, Ruth N. Prempeh and Elizabeth Y. Parkes Chapter 6 The Bumpy Path Towards Knowledge Convergence for Pro-Poor Agro-Biotechnology Regulation and Development: Exploring Kenya’s Regulatory Process 79 Ann Njoki Kingiri Part 2 Novel Applications 97 Chapter 7 Therapeutic Applications of Electroporation 99 Sadhana Talele VI Contents Chapter 8 Synthetic PEG Hydrogels as Extracellular Matrix Mimics for Tissue Engineering Applications 111 Georgia Papavasiliou, Sonja Sokic and Michael Turturro Chapter 9 Surface Aspects of Titanium Dental Implants 135 BioMed Central Page 1 of 15 (page number not for citation purposes) Retrovirology Open Access Research Requirements for the selective degradation of CD4 receptor molecules by the human immunodeficiency virus type 1 Vpu protein in the endoplasmic reticulum Julie Binette 1,2 , Mathieu Dubé 1,2 , Johanne Mercier 1 , Dalia Halawani 3 , Martin Latterich 4 and Éric A Cohen* 1,2 Address: 1 Laboratory of Human Retrovirology, Institut de Recherches Cliniques de Montréal, 110 Avenue des Pins Ouest, Montreal, Quebec H2W 1R7, Canada, 2 Department of Microbiology and Immunology, Université de Montréal, 2900, Édouard-Montpetit, Montreal, Quebec H3T 1J4, Canada, 3 Department of Anatomy and Cell Biology, McGill University, 3640 University Street Montreal, Quebec H3A 2B2, Canada and 4 Faculty of Pharmacy, Université de Montréal, 2900, Édouard-Montpetit, Montreal, Quebec H3T 1J4, Canada Email: Julie Binette - julie.binette@ircm.qc.ca; Mathieu Dubé - mathieu.dube@ircm.qc.ca; Johanne Mercier - johanne.mercier@ircm.qc.ca; Dalia Halawani - dhalawani@yahoo.com ; Martin Latterich - mlatterich@pharmacogenomics.ca; Éric A Cohen* - eric.cohen@ircm.qc.ca * Corresponding author Abstract Background: HIV-1 Vpu targets newly synthesized CD4 receptor for rapid degradation by a process reminiscent of endoplasmic reticulum (ER)-associated protein degradation (ERAD). Vpu is thought to act as an adaptor protein, connecting CD4 to the ubiquitin (Ub)-proteasome degradative system through an interaction with β-TrCP, a component of the SCF β-TrCP E3 Ub ligase complex. Results: Here, we provide direct evidence indicating that Vpu promotes trans-ubiquitination of CD4 through recruitment of SCF β-TrCP in human cells. To examine whether Ub conjugation occurs on the cytosolic tail of CD4, we substituted all four Ub acceptor lysine residues for arginines. Replacement of cytosolic lysine residues reduced but did not prevent Vpu-mediated CD4 degradation and ubiquitination, suggesting that Vpu-mediated CD4 degradation is not entirely dependent on the ubiquitination of cytosolic lysines and as such might also involve ubiquitination of other sites. Cell fractionation studies revealed that Vpu enhanced the levels of ubiquitinated forms of CD4 detected in association with not only the ER membrane but also the cytosol. Interestingly, significant amounts of membrane-associated ubiquitinated CD4 appeared to be fully dislocated since they could be recovered following sodium carbonate salt treatment. Finally, expression of a transdominant negative mutant of the AAA ATPase Cdc48/p97 involved in the extraction of ERAD substrates from the ER membrane inhibited Vpu-mediated CD4 degradation. Conclusion: Taken together, these results are consistent with a model whereby HIV-1 Vpu targets CD4 for degradation by an ERAD-like process involving most likely poly-ubiquitination of the CD4 cytosolic tail by SCF β-TrCP prior to dislocation of receptor molecules across the ER membrane by a process that depends on the AAA ATPase Cdc48/p97. Published: 15 October 2007 Retrovirology 2007, 4:75 doi:10.1186/1742-4690-4-75 Received: 23 July 2007 Accepted: 15 October 2007 This article is available from: http://www.retrovirology.com/content/4/1/75 © 2007 Binette et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0 ), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Retrovirology 2007, 4:75 http://www.retrovirology.com/content/4/1/75 Page 2 of 15 (page number not for citation purposes) Background CD4 is a 55-kDa class I integral membrane glycoprotein that serves as the primary co-receptor for human immun- odeficiency virus type 1 (HIV-1) entry into cells [1]. CD4 consists of a large lumenal domain, a transmembrane portion, and a 38-residues cytoplasmic tail. It is expressed primarily on the ... 4/7 Requirements for Human Life Harsh Conditions Climbers on Mount Everest must accommodate extreme cold, low oxygen levels, and low barometric pressure in an environment hostile to human life. .. able to evaporate, and internal body temperature can get dangerously high 2/7 Requirements for Human Life Extreme Heat Humans adapt to some degree to repeated exposure to high temperatures (credit:... friction and force of the pulsating flow of pressurized blood Chapter Review Humans cannot survive for more than a few minutes without oxygen, for more than several days without water, and for more