BLOG PART 3!

From the blogging activity part 2; we saw that neurotransmitters such as ATP and glutamate are released from the astroglia cells which may contact presynaptic nerons through gap junctions and by release of ATP. This allows for Ca2+ signals to release the transmitters to stimulate neuronal activity. The coupling of astrocytes and neurones results in very close communication between the cells. Neurone to astrocyte communication is promoted by glutamate which is released across the synaptic cleft. Released glutamate binds to glutamate receptors of the astrocyte which allows for the release of Ca2+.  This is a form of paracrine cell signalling; whereby the astrocytes secrete chemicals to the neighbouring neurons.

The neurones then communicate with each other; action potentials are generated whereby ions are allowed to move into the membrane. Neurotransmission occurs as well whereby communication between the neurons are established as chemicals or electrical signals moves across a synapse.

These signals are passed on to the myocardial cells of the heart muscles which makes up part of the myocardium. Myocardial cells connects via intercalated discs which contains desmosomes and gap junctions which allows the passage of ions and small molecules from one to another through connexions. The Ca2+ being passed from the astrocytes to the neurones then to the myocardial cells then allows for contraction of the heart muscle.

Contributions: Stephfana Williams; Sheillina Mohammed and Naomi Ramnanan

COMMUNICATION BETWEEN ASTROCYTES AND MUSCLE CELLS:

Endocrine signaling is responsible for long distance communication between cells. Endocrine signaling are called hormones so therefore a hormone is responsible for taking messages long distances away to cells in other parts of the body. Astrocytes release a variety of signaling molecules including glutamate, D-serine and ATP. Glutamate released from the astrocyte signals to the neurons in a feedforward or what is known as a long-distance signal. The release of this glutamate is initiated by Ca2+ ions causing a neurone-astrocyte-endothelial cell signaling pathway which plays an important role in neuronal control and vascular tone. These neurotransmitters are released into the blood vessels which takes the message along to other cells in a neurone-astrocyte-blood vessel pathway which is involved in the regulation of cerebral blood flow. When an astrocyte releases ATP and prostranoids they may signal to microglia hence having effect on the activation of these cells also the products that are secreated. A brain trauma is then followed by this occurance. The release of these neurotransmitters upon reaching its target cell binds to specific receptors on the cells as a key would fit into a lock. When this transmitter is in place the interaction triggers a response from the target cell allowing the contraction of muscle or stimulation of enzyme activity. Acetylcholine (Ach) is a transmitter in the brain released by neurons, when reaching the target site on a muscle cell it binds to the receptors opening a sodium chennels and causing muscle contraction. Antibodies that block one type of Ach receptor may lead to myasthenia gravis which is a disease characterized by fatigue and muscle weakness.

By naomiramnanan

Blog Part 2!!!

COMMUNICATION BETWEEN ASTROCYTES.
Astrocytes are star-like glia cells which hold neurons together, supply them with nutrients and digest the damaged parts of dead neurons. They communicate with each other via extracellular molecules, gap junctions, and intercellular channels. There is a chain reaction that occurs allowing the molecules to be passed on from one astrocyte to the other. Certain molecules inclusive of neurotransmitter glutamate creates an increase of Ca2+ in the cytoplasm of the astrocyte, also initiates secretion of ATP from the astrocyte, as well as causes calcium-dependent secretion of glutamate. The ATP that is now released out of the cell (Extracellular ATP) disperses to the neighbouring astrocytes activating membrane receptors which creates an increase of the Ca2+ in the neighbouring astrocyte. This then spreads to the neighbouring astrocytes. This extracellular mechanism allows synaptic signals to vibrate through the brain via glia cells. Studies show that ATP release and membrane permeability is associated with a transient outcome.
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COMMUNICATION BETWEEN ASTROCYTES AND NEIGHBOURING CELLS
Excitatory neurotransmitters such as, glutamate and adenosine triphosphate (ATP) are released from the astroglia cells. These astro glia cell contact many presynaptic neurones through gap junctions and by the release of ATP so Ca2+ signals can cause the release of transmitters from the astro glia cells to stimulate neuronal activity at synapses that are distant to the initiating synaptic event. Astroglia, presynaptic neurons and purkjne cells work together to transport electrical impluses and integrate from extracellular signals. For these signals to have an effect on the mouse it must be passed on to the pheripheral nervous system (muscle cells). The nerve cells meet with the muscle cells through neuromuscular junctions in which the chemical signal is transmitted. Vesicles containing neurotransmitters are released due to the influx of ions at the channel forming junction. It diffuses across a gap and bind to the receptors of the muscle cells in mouse thus a response such as jumping, running or fright and flight action is seen as interpreted by the mouse brain.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1226318/

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2375760/

Group members: Stephfana Willianms; Naveeta Barsatee; Juliana Mohammed

By naomiramnanan

NEW YEAR, NEW SEMESTER, NEW COURSES, NEW BLOG.

Hello readers, just so that you know, the days of blogging are back!!!! Yes….. I thought it was over too, but the great institute of UWI decides the fate of this blog and it says you must continue. So here we are bringing back the dead to life. Just so that you know, there is a twist here. Its the same writer, but a different course. The course I am continuing this blog for is Cell and Developmental Biology ( BIOL 2061).

In this blog we will be studying a particular cell of a mouse as well as the developmental of the cell….. Hence the title of the course. 

So no delays, 

h2_lets-begin

The mouse is a main asset to scientific research. For centuries scientists have been using the mouse as a research tool to enhance their knowledge about the human body. Now why use a mouse to gather information about the human body? Is there something wrong there? Actually no! There isn’t anything wrong. Us humans and those mice are very similar. No, we don’t have large front teeth, well…….. maybe some do, but we don’t have a furry coat attached to our skins or whiskers nor do we walk on four scrawny legs.

                To make sure of this, this is what a human and a mouse looks like:

HUMAN:   YEssss thats ROSE from Titanic!!!    

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MOUSE: Obviously the lab rats won’t wear clothes!!!!

6a00e54fcf73858834017d3d002b65970c-500wi

However we are both mammals and scientists have found that humans and mice a genetically similar to each other. Hence the mouse is used in the labs as “lab rats” to provide a wide range of data for medical researchers. Research is carried out on a broad spectrum of situations only naming just a few: genetic research, obesity, cancer, Alzheimer’s disease, blindness, hypertension, anxiety, aggressive behavior and the list goes on. All of which medical researchers are able to develop causes, effects, treatments and further studies on. The mouse is therefore an enhancement to the world of scientific data rather than a PEST to us humans.

Just like us, the mouse is a complex organism carrying out complex functions. They are not just a ball of fur. From the fur to the innermost part of their bodies are a complex network of cells, tissues and organs that work together for the proper functioning of the mouse. In this blog, I would be carrying out a study on one cell of the millions of cells in the mouse. This cell is called the PURKINJE CELL. It is found in cerebellar cortex which is located in the cerebellum of the brain.

The Purkinje cell usually originates from stems cells that are in close proximity. Stem cells are undifferentiated cells meaning that they are usually “born” without a function but they are capable of becoming any type of cell for example cells of the skin, bone, heart and brain. There are various forms of stem cells Fatal, Adult and Pluripotent Stem cells. The Purkinje cell usually develops from a Pluripotent stem cell. These cells can divide for a long period of time and are capable to make all types of cells within the organism.

Fig 1.1 THE IMAGE SHOWS THE BRAIN OF A MOUSE.

Fig 1.1 THE IMAGE SHOWS THE BRAIN OF A MOUSE. NOTE THE CEREBELLUM. THIS IS THE REGION IN WHICH THE PURKINJE CELLS ARE FOUND

Fig 1.2 THE POSITION OF THE PURKINJE CELLS IN THE CEREBELLAR CORTEX.

Fig 1.2 THE POSITION OF THE PURKINJE CELLS IN THE CEREBELLAR CORTEX.

 

The Purkinje cell as stated before is a cell found in the brain. This means that it is a member of the central nervous system. Yes nervous! Meaning the Purkinje cell is a nerve cell. It is therefore responsible for transmitting nervous impulses or messages from the brain to the different parts of the body. So from a stem cell to a juvenile Purkinje cell the cell develops and functions as a nerve cell.

Being a nerve cell, it means that it is made up of the following basic features: A cell body, a nucleus, dendrites, axon, myelin sheath, Schwann’s cells, Node of ranvier and axon terminals.

neuron

THE  CELL BODY: This is the portion of the nerve cell that contains the cytoplasm, nucleus, mitochondria, golgi apparatus and all other organelles inclusive of the genetic material of the cell exclusive of the dendrites and the axon. However, the dendrites and axon are attached to it. The cell body is important since it contains the main organelles that are responsible for the life and functioning of the cell.

THE NUCLEUS: Is the control center of the cell. The nucleus holds most of the cell’s genetic information or DNA and so being the control center it is therefore makes the function of the nucleus an important one.

THE DENDRITES: By looking at the diagram of a Purkinje Cell, you may find that it appears like a tree. Well the features that make the cell look like a tree are the dendrites. Because of the tremendous branching network, the dendrites create room for increasing surface area. This will aid in the reception of neural responses. The dendrites receive information and then pass it along to the cell body.

THE AXON: On the nerve, there is a long, thin projection of the Purkinje cell. This is responsible for conduction of electrical impulses that are being transmitted from the cell body.

THE MYELIN SHEATH: This is a layer of modified plasma membrane that surrounds each segment of the axon. It aids in insulation and conduction of the electrical impulses that passes through the axon.

THE SCHWANN’s CELLS: These are cells that belong to the peripheral nervous system. When a nerve fiber wraps itself around a Schwann cell, it forms something like a role resulting in the formation of the myelin sheath.

THE NODE OF RANVIER: These are gaps that are found along the axon that are uncovered with the myelin sheath of the axon. They aid in insulation.

 THE AXON TERMINALS: These are enlarged nerve endings. At this point the Purkinje cell connects to another nerve cell allowing the impulse to be sent to its destination.

 

FAREWELL!!!

Hey …. so this is the final post for the blog. It is probably the shortest post because the blogs are due today and well this week was quite packed for me at school. I really do hope that the blog was beneficial to you. As for me, my finals are in the next 2 weeks or so and I’m really hoping that this has contributed to the final percentage. I have learned a great deal from this assignment and I do hope that in some way or the other it would have been precise and vivid enough so that you fellow bloggers would be able to understand the essence of what was taught throughout our 12 week semester by our most favourite lecturer Mr.JM -_- J lol. After completion of this assignment after 12 looooooooooooooong stress-filled weeks and due to my lack of technical skills lol this is how I feel NOW

mission_accomplished_by_spark_burst-d5d936m

 

mission-accomplished

So any way hope you enjoyed it. Take care and bab bye for now…..

goodbye2

LIPIDS

honorlip
Basically lipids are organic molecules. these molecules are soluble in nonpolar organic solvents but are insoluble in water. Some of the functions of lipids are: they are a source of fuel, they act as an insulator for animals that hibernate, some are components of the lipid bilayer of the cell membrane and they are also a source of energy. There are different forms of lipids in the form of fats and oils, fatty acids, phospholipids, steroids as well as glycerol.

 For example, fats and oils are classified into as being saturated or unsaturated. Saturated fats are always in the solid phase whilst unsaturated fats are in the liquid phase. Saturated fats contains no double bonds, they come from animal sources and are correlated to heart diseases whilst the unsaturated fats have at least one double bond. These tend to be healthier than the saturated fats and come from plant sources.

 

TCA CYCLE:

Hi bloggers, so the last lecture review that was done was glycolysis. There we saw that a 6C glucose molecule was converted into 2 3C pyruvate molecules. The question after this is what happens to the pyruvate. Well under anaerobic conditions, it undergoes fermentation to produce lactate or ethanol. However, under aerobic conditions the pyruvate is converted to acetyl Co A which then enters into the TCA (tricarboxylic) or citric cycle. As we know glycolysis took place in the cytosol. TCA however takes place in the matrix of the mitochondriaMitochondria-562x359

and involves numerous enzyme catalysed reactions and reactions using NAD+ and FAD. These two molecules carry high energy electrons into the ETC.

TCA CYCLE……………………………………..

blaze_tca_cycle

The first reaction is a condensation reaction. This is where acetyl Co A is converted to citrate by the addition of water and removal of the Co Enzyme A. The second reaction involves a dehydration and a hydration reaction at the end of these two reactions isocitrate is produced. Oxidative decarboxylation of the isocitrate molecule occurs and alpha keto-glutatate is formed. Another decarboxylation then follows and this involves the conversion of the alpha keto-glutarate to succinyl Co A. Substrate level phosphorylation occurs to produce succinate which then loses water via dehydration to produce fumarate. Fumarate is then hydrated to maltate which then loses hydrogen to form oxaloacetate after which the cycle begins again. In general there are 8 reactions involved and each is catalysed by their various enzymes. The end products of the TCA cycle is therefore CO2, ATP, NADH and FADH.

REFERENCE: 

Mr. JM TCA slides. 🙂

PUBLISHED PAPER REVIEW # 2

THE GOLGI APPARATUS:  AN ORGANELLE WITH MULTIPLE COMPLEX FUNCTOINS.

golgi-apparatus

               The golgi apparatus is one of the many organelles of the cell. It is located differently in different organisms, but generally it has a packed cis-trans configuration. According to the research done, the golgi apparatus serves numerous function. These functions may be classified into transport and sorting, a biosynthetic center for proteins and lipids, a microtubule nucleation center, a calcium-store, signaling platform, a node in signaling pathways controlling homeostasis, ER stress response and nutrient sensing. In review of this paper, I would extend on three of the functions. these are transport an sorting, biosynthetic center and calcium store.

             According to (Biochem. J. ,2011) the golgi apparatus aids in the transport of transmembrane and soluble proteins to their final destinations. When these cargo molecules arrives at the golgi apparatus it must first be traversed after which they are sorted and sent to their final destinations.

            Proteins and lipids when they leave the golgi complex, they are covalently modified therefore giving them the ability to leave the golgi complex. According to Biochem.J., 2011, what this process does is that it “creates a biological gradient where post golg1 compartments are enriched in processed compounds while the pre-Golgi membranes are enriched in precursors and immature forms”. Hence it is stated that the golgi apparatus functions as a biosynthetic center for proteins and lipids.

            It is also agreed upon by the authors of the article that the golgi apparatus serves as a calcium store. According to the article, the golgi apparatus is capable of releasing Ca2+ during agonist stimulation and contributes to the time and way in which intracellular signalling of Ca2+ occurs. In addition to its linkage to Ca2+, the Golgi complex also releases Ca2+ when responding to the arrival of secretory cargo from the endoplasmic reticulum.

            What can be seen of this review is that despite the cell being so minute and even more so its organelles, they carry out numerous complex functions that enable life to be carried out the way it is supposed to. As many of you may have heard before, it is not the big things that matters so much, but it is the little things. Hence you can relate this to the cell and by extension the golgi apparatus.

 

REFERENCE:

Colanzi, A, C Wilson, G D’Angelo, L R.Rega, M.A De Matteis and L R.Rega “The Golgi Apparatus: An Organelle With Multiple Complex functions”Biochem.J (2011) 433, 1-9 (Printed in Great Britain) doi:10.1042/BJ20101058 1. Accessed April, 12 2013. http://www.biochemj.org/bj/433/0001/4330001.pdf

 

 

 

QUIZZ AGAIN??? :/ Yess :( Its just a treat not a threat!!! :)

GLYCOLYSIS:

Select the correct multiple answer using ONE of the keys A, B, C, D or E as follows:

A. 1, 2 and 3 are correct

B. 1 and 3 are correct

C. 2 and 4 are correct

D. only 4 is correct

E. all are correct the questions below:

 

  1. ATP is produced in the reactions where:
    1. Glucose is converted to Glucose-6-Phosphate
    2. 1,3-Bisphosphoglycerate is converted to 3-Phosphoglycerate.
    3. 2-phosphoglycerate is converted to phosphoenolpyruvate
    4. Phosphoenolpyruvate is converted to pyruvate.

 

  1. Which of the following enzymes belong to the energy investment phase?
    1. Aldolase
    2. Enolase
    3. Hexokinase
    4. Pyruvate kinase

 

  1. The conversion of 1,3-Bisphosphoglycerate is the
    1. First priming reaction
    2. Second primary reaction
    3. First ATP forming reaction
    4. Second ATP forming reaction

 

  1. Which of the followins occurs at the end of glycolysis?
    1. 2 ATP produced
    2. 2 NADH produced
    3. 2 ATP used
    4. 4 ATP produced

 

RESEARCH PAPER 1

Glycolysis inhibition for anticancer treatment. Published Paper Review.

Cancers, deadly diseases that takes innocent life away in the most painful and dreadful way. For some late diagnosis means early death and for others early diagnosis means slow agonizing death. For years cures for cancers has been postulated but till date, there is no evident cure. There are preventative measures, but for those that do acquire it treatments are available but it does not give a 100% chance of survival or the cancer being completely blasted out. There are many types of cancers out there that differ in genetic composition so to use a genetically based treatment would also mean that there isn’t a sure chance of survival since the disease may progress over time due to genetic instability. Oncogene (2006), suggest looking at the differences between cancer cells and normal cells in terms of metabolism can be a strategic was of irradiating cancer cells. They state that cancer cells depend on the glycolytic pathway (aerobic glycolysis) for ATP generation this is known as the Warburg Effect. Researchers established that if the glycolytic pathway was inhibited then there was a possibility of killing off the malignant cells.

So for those of you who are not aware of what glycolysis is, well, it is one of the most ancient metabolic pathways where energy is produced. Basically what happens is that in the cytosol of the cell, a glucose molecule is converted into pyruvate by a series of steps. The reaction occurs in the absence of oxygen and generates a net gain of two ATP molecules or molecule of energy. There are basically two phases of this pathway, the energy investment phase (EIP) and the pay-off phase both consisting of 5 different reactions and the use of 5  different enzymes to catalyse the reactions. The energy investment the breaking down in two molecules of ATP are burrowed to convert glucose into fructose 1,6 –bisphosphate. These reactions are catalyzed by the enzymes hexokinase, phosphoglucose isomerase, and phosphofructokinase. At the end of the EIP, a molecule of 6C glucose is converted into two molecules of 3C G3P. In the Pay off phase, the two molecules of ATP burrowed are repaid in when the conversion of 1,3 BPG to 3-phosphoglycerate occurs. In the reaction of phosphophenol to pyruvate the final product of glycolysis, two molecules of ATP are formed. Hence a net gain of 2 ATP molecules.

The ten reactions of glycolysis are catalysed by specific enzymes.  Since we’re talking about inhibition in of the glycolytic pathways, we will focus on these enzymes in their specific order according to the 10 steps of glycolysis talking about their relationship to cancer: This is explained in the table below.

ENZYME Role in glycolysis Relation to cancer cells
hexokinase Conversion of glucose to glucose-6-phosphate. Inhibition of this enzyme will cause effects in the cellular energy, metabolism and survival of the cell. Its an targetfor anticancer agents. 
Phosphohexose isomerase Converts glucose-6-phosphate into fructose-6-phosphate Associated with malignant aggressive tumors. 
phosphofructokinase Phosphoralates fructose-6-phosphate into fructose 1.6-bisphosphate The relation or involvement to cancer is uncertain. 
aldolase Splitting of fructose 1,6-bisphosphate into G3P and Dihydroxyacetone. Enzyme becomes elevated in the serum of patients that have malignant tumors.Overexpressed in human lung squamous carcinoma

 

G3P Dehydrogenase Conversion of G3P into 1,3 bisphosphoglycerate  Role unclear.
Phosphoglycerate Kinase Conversion of 1,3-phosphoglycerate into 3-phosphoglycerate  Found in all somatic cells
Phosphoglycerate mutase Conversion of 3-phosphoglycerate into 2-phosphoglycerate  Predominantely expressed in human lung carcinoma.
enolase Conversion of 2-phosphoglycerate phosphoenolpyruvate  Predominantely expressed in human lung carcinoma.
Pyruvate kinase Conversion of phosphoenolpyruvate to pyruvate  Allows tumor cells to survive in conditions O2 and nutrients concentrations differ.

 

So like said before, aerobic glycolysis plays a role in the vast increase of cancer cells. Energy  metabolism in this case is affected by mechanisms such as mitochondrial defects,adaptation to hypoxic environment in cancer tissues, oncogenic signals and abnormal expression of certain metabolic enzymes. In general , what these does is that they may cause cells to use glycolysis and be dependent on glycolysis for the production of ATP. As seen before the enzymes involved in glycolysis and maintenance of a high glycolytic level are factors of increasing malignancy and growth of these tumors. The point therefore is to prevent or inhibit glycolysis from occurring and this can be done by the use of enzyme inhibitors. The use of these inhibitors can stop glycolysis from occurring, ATP from forming and kill off cancer cells. Examples of these enzymes are 2-Deoxyglucose, Lonidamine, 3-Bromopyruvate, Imatinib (Gleevec), 6-aminonicotinamide.  For instance, 2-Deoxyglucose- is trapped in the cells eventually accumulating and leading to inhibition in the phosphorylation reaction with hexokinase. Lonidamine- inhibits aerobic glycolysis by inhibiting the hexokinase that is bound to the mitochondria in cancer cells and decreases the oxygen level. 3-Bromopyruvate can deplete the production of ATP and Imatinib (Gleevec) is a tyrokinase inhibitor which inhibits the factor reaponsible for the development of myeloid leukemia.

Basically, inhibition of glycolysis can be a treatment for the spread of cancers. However there are effects that must be taken into consideration that is; it is unclear that the other tissue users of  of glucose as its energy source e.g the brain can use alternative energy sources e.g. fatty acids.

 

Reference.

Martin, D S, H Pelicano ,P Huang,and R-H Xu “Glycolysis Inhibition For Anticancer Treatment” Oncogene Journal (2006). Accessed April, 08 2013. http://www.nature.com/onc/journal/v25/n34/full/1209597a.html

Video

Video Review

Hello people…. so for this biochem blog project, we were required to do two video reviews. So I decided I would use two of Mr. JM’s podcast. Since I believe that these were really great and very helpful in my study throughout the course. It enabled me to not be lost as I was for some of my subjects and thereby I do hope that it will lead me to passing this course. If I don’t well then………..(something just wrong). I therefore chose two of my personal favourite videos to review.

THE CELL.. 

 

 

So this was our first topic and what was learnt that the cell was described by Robert Hooke as the fundamental unit of all living things. Cells can be prokaryotic or eukaryotic. Be it either of these, the cell contains cytoplasmic material which contains organelles e.g ribosomes. The prokaryotic cell is usually smaller than that of the eukaryotic and contains circular DNA whilst that of eukaryotes contains linear DNA. Each of the many organelles present in the cell caries out different unique functions that enables them to perform life functions such as growth, metabolism and replication.  

So to review, basically this was what the video was about… 

 

GLYCOLYSIS:

In review of MR.JM’s podcast on glycolysis, this is what was done. Basically, glycolysis is one of the metabolic pathways in which energy is produced by the conversion of glucose in the cells to pyruvate. The glycolytic pathway is divided into two phases, the energy investment and the pay off phase. each of which has 5 different reactions catalysed by five different enzymes. In total, there are 10 steps in the conversion of a 6C glucose molecule into two 3C pyruvate molecules and 10 different enzymes. The reaction therefore results in a net gain of 2ATP and 2NADH molecules per glucose molecule converted. Glycolysis occurs in the cytosol and occurs in anaerobic conditions. 

REFERENCES:

http://www.youtube.com/watch?v=Y9c0VvUbmVQ&feature=youtu.be

http://www.youtube.com/watch?v=33JUjeo6-lE&feature=youtu.be

 

 

 

 

 

Enzymes Wordle!!!

biochem woordle

So after hard work and tireless failures at creating this wordle…. finally its done!!! YAAAAAAAAAAAAAAAAY! 😀 (lets hope that its worth the marks assigned)