Available online at www.sciencedirect.com Polyhydroxyalkanoates: bioplastics with a green agenda Tajalli Keshavarz and Ipsita Roy Production of polyhydroxyalkanoates (PHAs) has been investigated for more than eighty years but recently a number of factors including increase in the price of crude oil and public awareness of the environmental issues have become a notable driving force for extended research on biopolymers. The versatility of PHAs has made them good candidates for the study
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Microbiology Final Exam Question 1 2 out of 2 points Full induction of the lactose operon requires ________. Question 2 0 out of 2 points The enzymes that help pack DNA into the cell by coiling the DNA into a tight bundle are ________. Question 3 2 out of 2 points Gene regulation can involve a protein repressor that blocks ________ from initiating transcription. Question 4 2 out of 2 points Synthesis of a repressible enzyme is inhibited by ________.
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Alternative medicine has been around for centuries‚ although it has just started to become very popular in countries such as The United States. Many people now are following the trend without knowing anything about alternative medicine. People should be aware of the benefits as well as the precautions involved in taking these natural remedies. The most common form of alternative medicine nowadays is herbal medicines. These natural remedies can be found in millions of American homes today. Herbal
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observations. It was hard to tell what I was looking at. There were a number of amoeba shaped cells of varying sizes. There were five darker areas circular in nature. There were also three very large‚ odd shaped areas with distinct edges. Part 4: Direct Staining: Record your observations for each sample. Slide One: There were two distinct clusters that were easily noted. All the cells were cocci. Some of the cells were huge while others were practically nonexistent. Slide Two: There were layers of cells
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(bacilli)‚ and spirals Diversity of prokaryotes Gram negative vs. gram positive bacteria (Fig. 27.3) Gram + vs - -: less peptidoglycan -: outer membrane -: lipopolysaccharides in outer membrane Why are gram– more pathogenic? Lipopolysaccharides are often toxic Outer membrane protects against the body’s defences Outer membrane impedes entry of antibiotics Common antibiotics inhibit cross-linking of peptidoglycan‚ particularly in gram+ Motility ? Most motile bacteria propel themselves
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PHA came in existence until almost four decades later in 1926 when a French microbiologist Maurice Lemoigne discovered that a gram negative bacterium Bacillus megaterium accumulated intracellular granules of a polyester called polyhydroxy-3-butyrate (PHB) (Amara et al.‚ 2011). PHA accumulation ability has been reported for many microorganisms including Gram-negative and Gram-positive species (i.e. autotrophic‚ heterotrophic and phototrophic microorganisms‚ aerobes and anaerobes) as well as for a number
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Experiment 9: Growth curve of Serratia marcescens Abstract Bacteria grows by binary fission. The aim of this experiment is to follow the growth of Serratia marcescens in nutrient broth at 37oCby recording the changes in turbidity (cloudiness) by measuring the absorbance of visible light (600 nm) and also to prove that there is an increase in the cell number and not just in mass during the growth. In the experiment we measure the full growth curve of Serratia marcescens by measuring the absorbance
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swan neck flask caught the bacteria and the broth had no growth. 4) Who established microorganisms as the causative agent of infectious disease? How did he do this? What was the result of this body of work? * Robert Koch * Studied Bacillus anthracis * Took diseased mouse with anthrax and infected healthy mouse. This healthy mouse got sick. He then removed the spleens from the sick mice and isolated the anthrax spore. He injected that into healthy mice and they got sick.
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Several cells majority Bacillus and cocci cells. D. Were there observable differences between your fresh yogurt slide and the prepared yogurt slide? If so‚ describe them. Only perhaps that there was far more Cocci cells then Bacillus E. Describe the four main bacterial shapes 1. Cocci - Spherical or oval bacteria having one of several distinct arrangements based on their planes of division 2. Bacillus - Rod shaped bacteria. Bacilli all divide in one plane producing a bacillus‚ streptobacillus
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At the beginning of the semester‚ samples of bacteria were obtained from various sources. Two bacterial colonies were isolated from plates that were incubated in the lab and these bacteria became the basis for this project. The bacterial cultures were maintained and used for various physiological‚ cultural‚ and biochemical tests and observations over several weeks. The purpose of culturing bacteria over half the course of the semester was to learn various techniques used in microbiology labs and
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