Abstract
This paper highlights difficulties with using sequence data to estimate parameters about human ancestral populations, particularly times of specification (when new species evolved). The Y chromosome has been analyzed to infer various parameters about human ancestral populations and to provide clues as to human origins. The paper argues that the individual properties of this data source combined with a burgeoning list of refutable assumptions make any and all of these results utterly spurious. The paper argues that molecular experts claim that the old and imprecise science of paleontology has been superseded by their far more mathematically precise methods. These experts sideline the fact that all their estimates are fundamentally based on paleontologically acquired data. The paper includes illustrations and table.

From the Paper
"The Y-linked SRY gene triggers mammalian male-determining processes when expressed in the embryonic bipotential gonad. Sex chromosomes are thought to have evolved ~300Mya, probably replacing a mechanism based on gestational ambient temperature. Current opinion is that the Y-chromosomal SRY gene and its X-chromosome homologue (SOX3) are variants diverged from an ancestral non-sex-determining gene. When the ancient SRY-precursor gene gained a dominant and penetrant male-determining function the homologues became sex chromosomes and the process of dramatic degeneration and specialization of the Y began. Pseudoautosomal regions (PARs) located at the tips of X and Y recombine at high frequency during male meiosis. Consequently, these regions are similar to autosomal sequences in base composition and gene diversity. PARs comprise 5% of the Y and the other 95% makes up the non-recombining region of the Y (NRY). Recombination deficiency of the NRY is thought to result from lack of homology with the X, due to several large inversions. Null mutations accumulate in NRY genes as they are "sheltered" by X-chromosome homologues."

Tags:biology, genetics, mitochondria, mtdna, nry, sry

Abstract
This report explains in detail the function, structure and assembly of flagella in E.coli and Salmonella, using plain language and a number of diagrams. Movement (chemotaxis) is the primary function of flagella but its design also incorporates efficient repair capability and antigenic variation. In Salmonella and E.coli the flagellar filament is a homopolymer of flagellin monomers, although other species (such as Helicobacter) build their flagella from mixtures of two types of subunit. All the properties of the functioning filament are reflected in the structure of the flagellin monomer, which has conserved and variable regions, regions targeted by chaperones and coiling enzymes and regions evolved specifically for interaction between monomers. Chemotaxis is driven by a proton motive force (as in oxidative phosphorylation) and the basal complex that converts this energy into rapid rotation of the flagellum is highly complex.

From the Paper
"Many bacteria are motile and exhibit chemotaxis migration through the extracellular medium towards attractants (e.g. carbon sources), and away from repellents (e.g. antibiotics). The majority move using flagella protein structures variable in number and position (Box 1) that generate thrust by rotating like propellers. Flagella are 15nm in diameter and can be observed under light microscopy after thick metal staining or using advanced microscopy techniques such as electron microscopy. Because of the competitive advantages of chemotaxis, there has been strong selection for efficient chemotactic apparatus and flagellar efficiency. The flagellum is based in the bacterial surface layers where a complex array of proteins forms the flagellar motor. Resembling the electric rotary motor and the membrane-bound F1F0-ATPase, and powered by a proton influx across the inner membrane, this highly efficient machine is merely 30nm in diameter. Its mechanism is the subject of ongoing research."

Tags:antigenic, apparatus, bacteria, bacterial, chaperones, chemotaxis, coli, cytoplasmic, escherichia, export, flagellin, flagellum, motile, motility, salmonella, variation

Abstract
This paper examines how the nervous system is one of the major regulatory systems in the human body and like other systems is comprised of various organs and tissues. It looks at how the most important of these tissues are the nerve tissues which are composed of neurons and support tissues. It provides a summary of the synaptic structure and function as well as a description of the uses that modern drugs can have on the synapses to treat diseases.

From the Paper
"In excitatory responses an excitatory neurotransmitter, such as Acetylcholine, is released into the synaptic cleft. To begin with this only slightly depolarises the post synaptic membrane and is called an excitatory post synaptic potential. This makes the post synaptic membrane more easily stimulated if more neurotransmitters are released then depolarisation can occur more easily along the post synaptic membrane as described above. This excitatory post synaptic potential lasts only a few seconds and usually the postsynaptic membrane only can become depolarised if several end bulbs do this simultaneously, this is known as spatial summation. Another way in which the post synaptic membrane can become depolarised is if the end bulb receives many impulses very close together therefore releasing more neurotransmitter than normal, this is known as temporal summation."

Tags:central, cleft, nervous, neuron, neurotransmitter

Abstract
This paper examines how affinity maturation is a response to an antibody that occurs in vivo and how it can be defined as the gradual increase of antibody affinity for the immunizing antigen with time. It looks at how it is associated with an enhanced secondary (anamnestic) response, somatic hypermutation, isotype switching and memory development.

From the Paper
"Somatic hypermutation leads to mutations in the rearranged V-D-J sequences of antibodies. The antibodies generated during the primary response use the germline V regions, but in secondary responses all the generated antibodies contain a higher number of V-D-J region mutations. Random changes are introduced into the heavy and light chain genes and may lead to an increase in affinity of the antibody to the antigen. These higher affinity antibodies are then selected to enter the memory cell pool. The somatic mutations occur within the germinal centre in close proximity to the FDC network. If the variants have a high affinity for the antigen they are selected to become either plasma cells or memory B cells [4]."

Tags:antigen, cell, isotype, somatic, hypermutation

Abstract
This paper deals with how spots occur (inflamed lesions), and their subsequent bacterial growth. It gives details into how the effect of various concentrations of anti-bacterial facewashes affect the spread of bacteria. A thorough experimental aceptic technique is made reference to in this paper.

From the Paper
"A spot starts when a pore in the skin becomes blocked - usually with oil (sebum) and dead skin cells, which the skin produces. As the pore becomes blocked, it becomes infected with bacteria, which are normally present on the surface of the skin. These bacteria breakdown the oil and dead cells to form chemicals which cause swelling, redness and the formation of an "inflamed lesion" or a SPOT."

Tags:agar, anti, asceptic, bacteria, bacterial, clearing, coli, epidermis, inflamed, lesions, ph, spots, technique, temperature, zone

Abstract
The paper describes through examples, the principles that underpin modern developments in vaccination strategies. It gives a background to the development of vaccines, and describes how they work and the bodies immune response. It also looks at current developments in vaccinations and gives detailed descriptions of various vaccination methods. It uses specific U.K.examples with the MMR vaccine.

From the Paper
"The response to immunisation/vaccination can be enhanced by a number of agents, and collectively these are termed adjuvants. These are a heterogeneous group of compounds, with several different mechanisms of action. In the history of immunisation/vaccination, many compounds have been used empirically, with little knowledge about how they may work. Several vaccines are composed of proteins that have bee precipitated with alum, and others are emulsified in oil based compounds. One of the best known emulsifying agent's is Freund's complete adjuvant, which contains mycobacterial derivatives. Amongst these, bacterial cell wall components such as lipopolysaccharide are powerful immune stimulants, having an activating effect on macrophages and T-cells."

Tags:aids, bacteria, edward, hiv, immune, immunization, immunize, jener, medicine, mmr

Abstract
This paper explains, starting from the basics, what genetic engineering actually is, and how it is carried out. It details its uses in society and explains the risks involved and how to overcome them. Ethics and social values are included in the discussion.

Outline
Introduction
Principles of Genetic Engineering
Applications of Genetic Engineering
Hazards and Ethical and Social Implications of Genetic Engineering

From the Paper
"Restrictions have become less severe over the years, and genetic engineering is being applied more and more as public approval is constantly being sought. Nevertheless, this does not diminish the potential dangers of creating transgenic organisms. For example, consider the use of genetically modified organisms - GMO's - in the general environment, such as crop plants. Can such organisms be used safely? Suppose the pollen of these plants are transferred to wild relatives, thus injecting the gene into a different species. These plants may now act as weeds, and if the crop plants were engineered to be herbicide-resistant, then the weed will be similarly so. When a new type of oilseed rape resistant to the herbicide Basta was produced by the Belgian company 'Plant Genetic Systems' in 1994, there were concerns that rapeseed would act as a weed in hedgerows and would be impossible to control with Basta."

Tags:biotechnology, dna, gene, genome, gmo, nucleotide, plasmid, protein, virus

Abstract
This paper examines how mycobacterium tuberculosis is a very efficient pathogen with a uniquely successful method of pathogenicity. It describes why it is an excellent pathogen, features of a tuberculosis infection and looks at social and economic impacts. Treatment and control programmes are also mentioned. Although a number of control programmes have been developed to help eradicate the organism, there is no definitive answer to the major endemic.

From the Paper
"Mycobacterium tuberculosis does not produce toxins but it does however have a number of virulence factors that enable it to successfully infect a host. Cord factor (trehalose dimycolate) found in the cell wall is toxic and has both adjuvant and granuloma inducing properties, it also non-specifically activates macrophages.
The presence of secondary hydroxamates, which are iron-chelating agents, in the cell wall allows the bacteria to utilise the host's iron. The waxy outer capsule allows Mycobacterium tuberculosis to survive in air and dust for a long time, which contributes to the problems associated with eradicating this organism."

Tags:bacteria, disease, immunisation, pathogen, virulence

Abstract
This paper discusses how, since the publication of the human genome sequence in 2001, biologists have developed and applied a range of novel technologies in an attempt to extract the valuable biological information encoded within the genome sequence. In particular, it examines they way in which we have set about decoding the human genome to date and provides an insight into some of the progressive new technologies currently under development.

Outline
Objectives and Achievements of the HGP
Computational Biology and Genome Annotation
Comparative Genomics
Functional Genomics
Genetic Perturbations
The Transcriptome
The Proteome
The Interactome
Conclusion: The Rise of Systems Biology

From the Paper
"The objectives of the HGP can be considered as four overlapping goals: 1. The construction of high resolution genetic and physical maps. 2. A high quality, complete genomic sequence. 3. Identification of sequence variation within the human genome. 4. A complete list characterising each and every gene. Both working drafts have achieved almost complete sequencing of the euchromatic DNA in the human genome14. The highly repetitive nature of heterochromatic DNA renders its sequencing difficult and it is unlikely to be well represented even in the final sequence, anticipated by April 2003. To date, the public consortium (IHGSC) report that 75% of the human genome sequence is in "finished" state. That is, a continuous sequence with gaps no larger than 150kb and an expected error rate of less than 1 in 10,000 nucleotides. The public consortium's effort also resulted in a high resolution physical map of the genome, constructed to facilitate accurate assembly of sequenced fragments16. However, the genome sequence itself represents a physical map of the highest possible resolution."

Tags:bioinformatics, organisms, proteomics, transcriptome

Abstract
The following paper examines the isolation of human embryonic stem cells. The author attempts to discover what these cells are and why they are so important. This paper will also take a look at those people that recommend the use of other sources of stem cells for medical reasons.

From the Paper
"This will potentially revolutionize medicine in the next century" (Smith, 1999)1 . The use of stem cells to develop drugs, study human development and provide a limitless supply of customized cells to replace damaged or diseased tissues, without incidence of adverse host reaction has replaced cloning as the perceived future of medical technology. The "Holy Grail" concept revolves around the knowledge that stem cells have the potential develop into any of the body's two hundred and twenty different types of specialized cells. The therapeutic promise of this is that once a stem cell has been isolated, it may reproduce endlessly in undifferentiated state and then be chemically coaxed to develop into any desired adult cell. Stem cells may eventually be used to produce tissues or entire organs specifically designed for their intended recipient. Cellular repair treatments for Alzheimer's and Parkinson's diseases as well as many forms of paralysis, previously irreversible autoimmune conditions, are the most exciting channel for this field of research. The potential uses of these unrestricted cells could even go as far as the generation of massive amounts of human cells (e.g. heart cells) which could be used to screen dozens of potential drugs and pick out the most promising few, without harm to human or animal life."

Tags:medicine, century, drugs, study, human, development, customized, genetics