AIDS: the most political epidemic of our times - Essay Example

Review Questions A. The epidemic on an infectious disease is not only caused by the infectious agent; it is many a times the resultant of the social, political, economic, and infrastructural failures. One such epidemic is AIDS, which is called the most political epidemic of our times. When AIDS first broke out in USA, the government at that time did almost nothing to contain the disease. The leadership just decided to remain silent and inactive in 1981, and their response to the spreading epidemic was called as "halting and ineffective". With the epidemic spread of the disease, the researchers, epidemiologists, and healthcare professionals were in dire necessity of funds to develop tools to contain the disease, but they were denied funds due mainly to political lobbyists. When a statement from the government would have oriented people to the appropriate directions, rather than effective leadership to consolidate the approaches against AIDS, the authority took an unscientific standpoint to relate AIDS to particular sexual behaviors. This was a politically directed move to discriminate against people with AIDS. The government rather than concentrating on preventive measures or AIDS education, being politically mobilized by the born-again Christian Republican conservatives embraced a deeply reactionary social move. When the government chose to take steps, by that time AIDS was established epidemic in USA. B. The outbreak of SARS was the result of ineffective government policies at the national level, mainly due to economic reasons. Normal domestic response to an emerging epidemic should be effective gathering of information and transmission of that data to appropriate specialists to assess that. Fears that disclosure of SARS would affect tourism and business and danger that both of these would affect economy, made China to make a delayed disclosure of this atypical illness. This delay had already caused the spread of the disease until the attention of the international community was attracted to this. The economic interests caused lack on transparency by the Chinese Government. The global spread of the disease is attributed to poor transparency of this government. In the case of an outbreak, performance of basic public health functions is important to trace contacts for sick patients. This needs a very strong economy of the country, and aggressive steps in this context would need costly steps and surge of extra fund. Many countries lack such amenities mainly due to economic reason. This fuels the spread of the epidemic. The fear of diversion of foreign direct investment in the geographic region is not unreal, and SARS led to foreign divestments in China. 4A. The Embden-Meyerhof Pathway or Glycolysis: In this pathway, a series of enzymatic chemical reactions lead to conversion of sugars to pyruvate resulting in ATP production. Glucose is phosphorylated to glucose-6-phosphate, the ATP in the cell acts a phosphate donor, and it is transformed into ADP. By a reversible reaction, glucose-6-phosphate converts to fructose-6-phosphate. Fructose-6-phosphate, in turn, is phosphorylated at 1 position of the carbon chain of the fructose-6-phosphate. This phosphate is derived from another molecule of ATP, which gives one phosphate radicle and is changed to ADP. The fructose-6-phosphate is converted to fructose-1-6-biphosphate. This marks the end of 6-carbon stage of the reaction. Next, an enzyme, aldolase acts on fructose-1-6-biphosphate to form glyceraldehyde-3-phosphate and dihydroxyacetone phosphate, which are interconvertible by a reversible reaction between them. In this step, another phosphate is incorporated into glyceraldehyde-3-phaosphate by mediation of NAD to result in 1,3 biphosphoglycerate. In this process, one H+ ion is incorporated into NAD to form NADH. Next, a substrate-level phosphorylation occurs. This splits one phosphate from the 1,3 biphosphoglycerate to tag it to ADP, generating one molecule of ATP. Biphosphoglycerate is converted into 3-phosphoglycerate that reversibly forms 2-phosphoglycerate. Elimination of one H2O leads to phosphoenolpyruvate that can again be dephosphorylated to form pyruvate, and this phosphate can be incorporated into ADP leading to generation of another molecule of ATP. Since 1 molecule of fructose-1-6-biphosphate breaks into 2 molecules of glyceraldehyde-3-phosphate, 4 ATP can be produced from one molecule of glucose with consumption of 2 molecules of ATP in the 6 carbon stage with a net gain of 2 ATP. 4B.The other pathway is bacterial photosynthesis. The bacteria that use photosynthesis for ATP generation have chlorophyll a. These absorb energy from the sunlight. This energy triggers chemical reaction called photosynthesis. In the first stage, sunlight induces photophosphorylation that uses H+ ions derived from H2O to produce ATP from ADP and NADPH from NADP+. This is known as light reaction. In the next phase of dark reaction, the products of light reaction are used to from C-C covalent bonds of carbohydrates. The light reactions use higher energy state electrons via electron transport processes. In the light-independent stage, CO2 from the atmosphere is captured and modified by addition of hydrogen to form carbohydrates through Calvin-Benson cycle. CO2 is captured by ribulose diphosphate (RDP), thus converting into a 6-carbon skeleton compound. This intermediate gives rise to two molecules of 3-phosphoglyceric acid. The energy from the ATP and NADPH previously produced are used in this process. The ribulose biphosphate carboxylase oxygenase catalyzes combination of 6 molecules of CO2 to ribulose biphosphate. This is broken down to 12 molecules of 3-phosphoglyceric acid. These 12 phosphates are derived from 12 ATP molecules. Hydrogen ions derived from NADPH reduces the phosphoglyceric acid molecules to 12 molecules of phosphoglyceraldehyde (PGA). Two of these PGA synthesizes fructose and glucose. The rest 10 molecules re-form 6 molecules of 5-carbon ribulose phosphate and 6 phosphate groups derived from 6 ATP releasing one phosphate each. The ADP, in turn, is converted to ATP by photophosphorylation. Two water molecules break down into 4 electrons, 4 hydrogrn ions, and oxygen. These electrons reduce NADP+ to NADPH. The H+ ions participate in reduction of NADP+ to NADPH. While passing along the concentration gradient, these protons also give up energy that is used for conversion of ADP to ATP. Q.5.A. Bacteria have established systems of communication. This can happen with individual bacteria at genomic level, in between themselves in a colony of single species, and between different species when there is a polyspecies existence. They use different forms of biologic messenger system, such as, inorganic molecules in the system, peptides, proteins, and genetic sequences. This communication can happen through an inducive message system, where bacteria can induce specific changes within the cell of itself by the messenger chemical. The other method is informative message system by which the chemical agent or signal initiates nonspecific cellular responses that initiates an interpretation process based on previously stored information within the cell. A1a. The most important informative message system works through the bacterial production of an extracellular chemical known as acyl-homoserine lactone that accumulates in the culture colonies at high bacterial density. A1b. When the bacterial load is low in a biological environment, this sensing mechanism does not work. When there is sufficient colony count, this sensing mechanism comes into play. Thus, if the result of this system is to produce a virulence factor, this awaits until there is a sufficient count of the bacteria to produce virulence. The same principle and method may be applied to the process of development of bacterial resistance. A2a. This mechanism enables the bacteria to sense environmental changes. When this sensory mechanism is activated, this leads to alterations in gene expression through induction of response regulator proteins. This is intended to produce cellular adaptation to the changing environment. It has been postulated that this is one of the ways of development of bacterial resistance to antibiotics. A2b. Biofilms are bacterial groups surrounded by extracellular polymers. This bacterial communication is mediated by chemical signals that lead to co-ordination of group activities of bacteria. This is a group of molecules known as autoinducers that regulates mRNA production of specific genes in response to bacterial density. Certain peptides have been identified that can interact with specific repressor or activator sequences in bacterial DNA. A3a. This common signal mechanism is used to monitor the general level of the surrounding bacterial population and levels of activity so that they can come together within the biofilm. Apart from other benefits, this is a method for enhanced bacterial mating that enables them to acquire unique DNAs from one another by transformation. This organization points to increased diversity of the bacteria. A3b. The autoinducer peptide signals controls production of bacterial protein. These proteins are encoded by genes for biofilm production. Bacteria often produce minute quantities of antibiotics that inhibit growth of competitive strains. When brought together in biofilms, the amount will be good enough to block the growth of other bacteria. This will also enable them to produce toxins that cause disease in the host that would have been, otherwise, impossible while isolated. B. Bacteria can adapt to the environment by many ways. Two of the examples are development of antibiotic resistance and alteration of lipopolysaccharide in their cell wall. B1. With response to antibiotics, the bacteria may induce some changes in the genetic make-up of their genome. This may result in some mutations, where the new bacterial population will be inert to the effect of the antibiotic. B2. Gram-negative bacteria have layer of lipopolysaccharide outside their cell wall. Alteration of growth condition will induce changes in this layer. If it is an artificial medium, the lipopolysaccharide is more water repellant or hydrophobic and when within a living organism, the lipopolysaccharide will become less water repellant or hydrophobic. Read More