RNA interference (RNAi) is a gene-silencing process during which endogenous messenger RNA (mRNA) is destroyed by introduced corresponding double-stranded RNA [1]. RNAi has found widespread application as a technique in research laboratories, since it permits the simple yet effective knockdown of genes of interest. RNAi-related processes are physiologically critical for development and heterochromatin formation, and offer cellular protection against virus and transposon amplification [2]. Despite the widespread use of RNAi for the knockdown of genes, the RNAi pathway, especially the detailed mechanisms underlying the formation of RNA-induced silencing complex (RISC), remains poorly understood.

Small interfering RNAs (siRNAs) were first identified as the specificity determinants of the RNAi pathway, wherein they act as guides that direct the endonucleolytic cleavage of their target RNAs. Prototypical siRNA duplexes are 21 nucleotide (nt) double-stranded RNAs (dsRNAs), containing 19 base pairs and 2-nt 3′ overhangs.

The results of several in vitro experiments indicate that only one strand of the siRNA duplex is loaded onto RISC, which in turn uses this strand as the guide RNA to find complementary mRNA sequences via Watson-Crick base pairing and cleaves the phosphodiester bond between the 10th and 11th nucleotides in the target molecules via an endonucleolytic pathway as measured from the 5′ end of the guide strand. Although it is reported that the selection of the guide strand is based on the rule of thermodynamic asymmetry, the way selected guide strand is released from the double-stranded siRNA and the fate of the anti-guide strand remains unclear. It also remains to be investigated whether the results obtained using in vitro RNAi reaction systems reflect the actual events occurring in mammalian cells.

Wei J-X, Yang J, Sun J-F, Jia L-T, Zhang Y, et al. (2009) Both Strands of siRNA Have Potential to Guide Posttranscriptional Gene Silencing in Mammalian Cells. PLoS ONE 4(4): e5382. doi:10.1371/journal.pone.0005382

siRNA Transfection too remains a challenging task for some difficult to transfect cell lines.

Babesiosis (Babesia microti) is a malaria like parasitic disease caused by “Babesia”, a genus of protozoan piroplasms. Babesiosis exists as a variety of diseases in 3 distinct groups:

(1) asymptomatic infection,

(2) a mild/moderate viral-like syndrome, and

(3) severe disease that causes persistent relapsing course or fulminant course leading in death.

The disease is a vector borne sickness commonly transmitted by Ixodid ticks. Babesiosis is a zoonotic disease maintained by the interaction of tick vectors, host migration, and animal sources. It is common in endemic regions of the north eastern and north western America, especially Long Island, New York, and Nantucket and Martha’s Vineyard, Massachusetts. Babesiosis also occurs in regions of Europe and Asia, where the tick vector and vertebrate host reside.

Babesia

Babesia microti employs the similar tick vector, Ixodes scapularis similar to Lyme disease and ehrlichiosis, and could occur in conjunction with these other diseases. Babesia parasites multiply in red blood cells, where they can be seen as cross shaped inclusions and cause haemolytic anaemia similar to malaria. Babesia canis and babesia bigemina are “large babesias” that form paired merozoites in the erythrocytes , normally depicted as resembling “2 pears attached together”, rather than the “Maltese Cross” of the “small babesias”.

Ticks

Ticks and tickborne bacterial diseases in humans are an emerging infectious threat. Ticks can express both babesiosis and Lyme disease. Ticks can carry the babesia microti parasite in the red blood cells of many creatures, including man. Ticks ingest babesia while feeding from the host animal and the parasite multiplies within the tick’s gut wall. Ticks found before attachment should obviously be removed, while ticks found after attachment should also be removed to limit the possibility of transmission within 24 hour after attachment.

Symptoms

Symptoms tend to be more evident and grievous in immunocompromised persons. Symptoms are related to RBC parasitaemia. The symptoms begin with fatigue, loss of appetite, and a common ill feeling. The symptoms of babesiosis frequently do not lead directly to the underlying diagnosis and many symptoms can be misleading. Other symptoms include high fever (up to 40 degree Celsius (or 104 degree F), chills, diaphoresis, helplessness, fatigue, anorexia and headache.

Postdoctoral researchers are those who have a PhD and have embarked on an academic path that will eventually lead to a full time permanent position as a principal investigator. Most postdocs are in their 20’s or 30’s and some even 40’s and have recently completed their PhD in subject of interest. After completion, several of these new PhD’s take up postdoctoral positions within their own department as they have are familiar with the surroundings. Some even take a Postdoctoral job outside their country even though the Postdoctoral salary in some countries is bad including Europe and the United States.

Some of the duties involving a postdoctoral researcher include;

1. Carry out research and publish papers
2. Supervise PhD students and design experiments for them and read their reports
3. Help the mentor/principal investigator in preparing for grants
4. Be a manager to the mentor/principal investigator

Interestingly about 50% of postdocs in the United States are of foreign origin. Most of these postdocs dream of becoming a principal investigator and leading a team of their own. As a postdoc myself, I have realised that some no longer want to stay in science at all. Some of my ex-colleagues have either taken up scientific non-lab work such as medical writing and sales repping while some have completely left research for good.

The first stage of atherosclerosis is believed to be endothelial dysfunction. The features of the earliest stage of atherosclerosis are the expression of lectin-like oxidized-low-density-lipoprotein receptor-1 (LOX-1), vascular cell adhesion molecule-1 (VCAM-1), and intercellular adhesion molecule-1 (ICAM-1).

Oxidised low-density lipoprotein (oxLDL) is crucial in the trigger and evolution of atherosclerosis. The main endothelial receptor of oxLDL, LOX-1, is responsible for adhering, internalisation, and degradation of oxLDL in endothelial cells. Both invitro and invivo experiments have demonstrated the receptor to be crucial in the initiation of atherosclerosis and to be upregulated by pro-atherogenic factors, for example. shear stress, tumour necrosis factor (TNF)-α, and oxLDL itself.

In addition, VCAM-1 and ICAM-1 also play crucial roles in the process of coronary artery disease as they’re critical to leukocyte adherence, rolling, and trans-endothelial migration. VCAM-1 is mainly an inducible molecule, whereas ICAM-1 is also constitutively expressed on resting endothelial cells. They are both up-regulated by pro-atherogenic agents. VCAM-1 has, based on experiments with knockout mice, been recognised as the major adherence molecule in the trigger of atherosclerosis. A high degree of soluble ICAM-1 (sICAM-1) in plasma has been linked to increased risk of cardiovascular events, as well as to cancer and autoimmune disorders.

Micrograph of a coronary artery

Coronary heart disease (also called Atherosclerosis) is a disease of the arteries. It causes it to ‘harden’ affecting both medium and large arteries. It is the main cause of heart attacks and strokes responsible for over 50% of all bereavement in the western world and continues to be a major worry in developing countries.

The disease is one of the single most financial drain of the health service of several nations. The disease is mainly triggered as a response to chronic injury to the vascular endothelium. This can be due to a variety of insults such as blood pressure, stress and oxidative damage (such as smoking).

The endothelial damage from this injury leads to a response that causes the arteries to compensate the damage by altering the normal homeostatic properties. For example, the damage increases the adhesiveness of the endothelium to leukocytes (white blood cells) and platelets. Additionally this injury enhances the permeability of the artery. The injury also causes the endothelium (cells that line the blood flow of blood vessels) to produce agents such as cytokines and growth factors (signaling molecules) that then cause further progression of the inflammatory response. This then causes the migration and the proliferation of smooth muscle cells (contractile cells present in hollow organs) to form an intermediate lesion, which progresses to produce further lesions called the plaque leading to the thickening of the artery wall.

As inflammation and atherosclerotic insult continues, more white blood cells migrate to the lesion. The white blood cells become activated leading to increased production of cytokines, chemokines, growth factors and hydrolytic enzymes that then cause further damage. This ultimately leads to the formation of advanced lesions and blockade of the arteries causing clinical complications such as stoke and heart attack.

As an author, I have realised that our results are accepted as a scientific publication on the basis of innovative experiments and techniques.

The documentation produced for submission to journals has to be written in a well structured way that are concise, logical and explained in a manner that can be is easily understood by all audiences both scientific and medical.

In order to achieve the desired level; the article should therefore consist of diagrams, tables and well thought out explanations. The authors should communicate and justify their findings completely and accurately.

Firstly, the quality of a publication can be assessed by the ability of the authors to convey their initial messages in a well written abstract. It is very much like a precis. A precis is a summary of a detailed document like a headline or the opening sentences of a newspaper. This is where an author should make use of their skills to attract their audiences. A good summary should make a less interested reader read at least some part of the paper. This is where the authors sell the paper to the referee or editor for getting their work published in high impact journals.

In order to make a judgement of the remaining document, quality can be classified in simple categories depending on clarity, details, quality and design of the experiments, and richness of the arguments. The classifications are as follow;

Exceptional: The designs of the experiments are novel, well thought out and the experiments produced are of exceptional quality and no such scientific research have been previously been produced. There is good correlation between the citations and the text. The results are critically evaluated with references to previous work. The paper actually justifies discussion.

Good to acceptable: The article is well articulated and presented in concise and logical way. The experiments are well thought out, the quality of the experiments are decent and carried out several times to establish justification with statistics.

Poor: Even if the experiments are of good quality and potentially useful, a poorly written article with several grammatical errors can be rejected by the editors. The authors have not read the “instructions to authors section”. It seems as if it’s a trial and error exercise to get their work published. It would be most appropriate to approach a scientific communications expert or a technical writer on such occasions.

Stem cells have the remarkable potential to develop into many different cell types in the body. Serving as a sort of repair system for the body and organs, they can theoretically divide without limit to replenish other cells as long as the person or animal is still alive. When a stem cell divides, each new cell has the potential to either remain a stem cell or become another type of cell with a more specialized function, such as a muscle cell, a red blood cell, or a brain cell.

Stem cells have two major features that separate them from other different types of cells. Firstly, that they are unspecialized cells that activate one another for long periods via cell division. Secondly, stem cells can undergo detailed physiological and/or under certain experimental conditions, they can be activated to become cells with really extraordinary functions. These can include; cells of the heart muscles or even like insulin generating beta-cells of the organ pancreas.

Scientists initially worked with two categories of stem cells derived from animals and humans namely the embryonic stem cells and adult stem cells. Both have separate functions and features and both have been extensively studied. Researchers established ways to acquire or use stem cells from premature mouse embryos as early as 20 years ago. Two decades of extensive research in this area of biology of mouse stem cells led to the discovery of how to separate stem cells from human embryos and grow the cells in the lab. Today they have been named as human embryonic stem cells. The embryos used in the research were created for infertility cases in the process of in-vitro fertilisation methods. With the counselled agreement of the donor if they were no longer required for that motive, they were donated for experiment.

Today Stem cells are one of the most striking areas of biological science. But like many growing areas of scientific research, it has been heavily debated and research on stem cells raises scientific queries as almost immediately as it sets off new discoveries.

Spectrophotometer is an instrument used to measure the transmission or reflection of light of a specified wavelength passing through a medium. The idea is that the amount of light absorbed by the medium would be proportional to the concentration of the material or solute present in the medium. So, using this principal, the concentration of a solute in a solution is hence measured by the absorbance of light at a particular wavelength. To measure a sample, the solutions would be placed in a cuvette and placed in the machine after adjusting wavelength and calibrating to zero.

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Does DNA provide the evidence of an intelligent design by GOD or an occurrence of nature and evolution? According to Theodosius Grygorovych Dobzhansky “Nothing in biology makes sense except in the light of evolution.”

Role of Introns

Role of introns: Left over’s of evolution or evidence of intelligent design

Often genes are composed of coding regions called exons and internal non-coding regions called introns. The genes in higher eukaryotes interrupted by intragenic non-coding sequences called introns are loosely called “nonsense genes”. The role of introns is a topic of great interest in gene research and evolutionary circles. There are several theories and suggestion of the role of introns or “junk” DNA as to why they use a vast amount of cell resources and almost all cases not transcribed into protein and if it does; show non-protein functions or has no functions.

Evolutional theory suggests that there existed DNA with no coding regions that later evolved to some coding regions to produce cell structures and protein and hence the earliest form of single cell organisms. Evolutionists argue that the large sections of DNA that have no purpose are “junk” DNA and uses large amount of energy and resources by the cell and carries no function; cannot be a design of an intelligent designer. Hence the genome shows proof of evolution and subsequently no sign of design.

It is thought that introns were introduced during evolution by viruses into the human genome or by faulty DNA replication. To encourage genomic diversity, genes that undergo alternative splicing produce multiple copies of the same gene. It is also hypothesised that several genes were non functional but evolution and selection pressure allowed conversion into functional genes such as genes coding proteins to allow cell survival.

Another theory suggests that proteins from these introns where once harmful and hence made redundant to prevent harm to the cells and the organism. Alternatively, it is also possible that the whole human genome including introns were once functional and served a purpose for survival and now not required. The DNA also might have rearranged and reordered to create new sequences that code for novel proteins required for new functions.

Although the roles of all introns are not fully known, some preliminary research shows that not all introns are junk DNA and might have profound roles not yet known. For example, it might have been associated with creation of new genes during evolution (exon theory of genes), it may be important for the expression of some genes on which the intron exists and required for alternative splicing to create variations of mRNA of a gene.

The NanoDrop is the new state of the art low volume Spectrophotometer that allows very small quantities (1 µl) of nuclei acids and proteins to be analysed rapidly, without the use of traditional cuvettes and eliminating the task of diluting samples. Watch the official NanoDrop video.