Latest Entries »

All organisms are made up of specialized cells forming tissues and then into organs. Zebrafish has many specialized cells such as brain cells, skin cells and osteoblast cells. Certain stimuli will result in the skin cell receptors sending a signal to the brain cells (HIT 1). If the stimulus is a wound damaging the bone of the fish, the brain cells can then send signals to osteoblast cells to rebuild back the bone lost/damaged (HIT 2). The former would have calcium signaling followed by a series of transaction cascade of signals to the brain while in the latter; the regeneration of the cells is done by Wnt/Beta-catenin signaling.

Image

Figure 1 G protein signaling

G protein leads to a release of Ca2+ into the cytosol changing its concentration.

Image

The signals can act as a neurotransmitter to send to various part of the body. the brain send signals to the effectors. to the osteoblast

.Image

Description:

“The conserved Wnt/β-Catenin pathway regulates stem cell pluripotency and cell fate decisions during development. This developmental cascade integrates signals from other pathways, including retinoic acid, FGF, TGF-β, and BMP, within different cell types and tissues. The Wnt ligand is a secreted glycoprotein that binds to Frizzled receptors, which triggers displacement of the multifunctional kinase GSK-3β from a regulatory APC/ Axin/GSK-3β-complex. In the absence of Wnt-signal (Off-state), β-catenin, an integral E-cadherin cell-cell adhesion adaptor protein and transcriptional co-regulator, is targeted by coordinated phosphorylation by CK1 and the APC/Axin/GSK-3β-complex leading to its ubiquitination and proteasomal degradation through the β-TrCP/SKP pathway. In the presence of Wnt ligand (On-state), the co-receptor LRP5/6 is brought in complex with Wnt-bound Frizzled. This leads to activation of Dishevelled (Dvl) by sequential phosphorylation, poly-ubiquitination, and polymerization, which displaces GSK-3β from APC/Axin through an unclear mechanism that may involve substrate trapping and/ or endosome sequestration. The transcriptional effects of Wnt ligand is mediated via Rac1-dependent nuclear translocation of β-catenin and the subsequent recruitment of LEF/ TCF DNA-binding factors as co-activators for transcription, acting partly by displacing Groucho-HDAC co-repressors. Additionally, β-catenin has also been shown to cooperate with the homeodomain factor Prop1 in context-dependent activation as well as repression complexes. Importantly, researchers have found β-catenin point mutations in human tumors that prevent GSK-3β phosphorylation and thus lead to its aberrant accumulation. E-cadherin, APC, and Axin mutations have also been documented in tumor samples, underscoring the deregulation of this pathway in cancer. Furthermore, GSK-3β is involved in glycogen metabolism and other signaling pathways, which has made its inhibition relevant to diabetes and neurodegenerative disorders.”

Quoted from: http://www.cellsignal.com/reference/pathway/Wnt_beta_Catenin.html

                              STEM CELLS IN ZEBRA FISH

 

    Stem cells help the body to grow or regenerate damaged cells or tissues. The results obtained in this study demonstrate that retinal stem cells are multi-potent and a single stem cell can develop into all retinal cell types. They interact with each other and as a results it indicate that the growth of the retina is regulated by controlling stem cell proliferation, In addition in the same organ – the fish eye – a second class of stem cells exists besides the multi-potent retinal stem cells: the stem cells of the pigmented epithelium. They all communicate and work together to carried out their main functions in the tissues.

Image

 

 

OSTEOBLASTS IN ZEBRA FISH

 

   Osteoblasts are cells with single nuclei that synthesize bone. However, in the process of bone formation, osteoblasts function in groups of connected cells. Individual cells cannot make bone, and the group of organized osteoblasts together with the bone made by a unit of cells is usually called the osteon.so it can be seen that they communicate with each other. Osteoblasts are specialized, terminally differentiated product of the stem cells.

http://en.wikipedia.org/wiki/Osteoblasts

Image

 

COMMUNICTION BETWEEN STEM CELLS AND OSTEOBLASTS IN ZEBRA FISH

 

   Stem cells in a tissue can also communicate with other cells in neighbouring tissue such as the osteoblasts. We utilize growth of the zebra fish fin to reveal underlying cellular and molecular mechanisms regulating bone growth. Fins are comprised of segmented bony fin rays surrounded by a multi-layered epithelium.  The hemi rays surround a loose mesenchyme of undifferentiated cells as well as blood vessels and nerves. Distally, the hemi rays are lined with collagen-like fibrils called actinotrichia, which serve as the substrate for osteoblasts. Osteoblasts are found laterally in association with the bone matrix, while the mesenchyme is located medially. Cell proliferation or stem cells contributing to new fin growth occurs medially and in the distal mesenchyme .Thus, growth occurs at the distal end of the fin. During fin regeneration all of the tissues of the zebra fish fin are restored in form and function. In particular, osteoblasts must continuously differentiate for outgrowth of the bony fin rays. Regeneration begins with the help of the stem cells and wound healing by the migration of epithelial cells to cover the wound.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2788789/#R5

 

Image

Notch signaling regulates differentiation of certain cells and maintains mature tissue homeostasis. In this case, it enables the stem cell compartment to expand into osteoblast differentiation in bone development. The description of the pathway can be described as seen in http://www.cellsignal.com/reference/pathway/Notch.html

STEM CELLS IN ZEBRAFISH

This is my life!!! I am a STEM CELL……!

 

PART 1) 

             The model organism I chose is a Zebra fish

Image

 

    Model organisms are those useful information that have been already combined to described basic biological processes. There are questions that are asked about their structures and features, the model organism (zebra fish) can be very easily to assess and manipulate. So when selecting a living organism such as the zebra fish there is a wide range of characteristics. In this assignment, I will be doing a cell type from the zebra fish which is the stem cell.

 

Image

 

    The model organisms that are being used helps students to understand important concepts in different disciplines. As we know, the zebra fish is a common and useful model organism for the studies of vertebrate development and gene function in biology. The fish has a online database of genetic, genomic, and development information. They are also useful in scientific research because the model change in the environment will enhance the students’ learning and will allow the students to give all it’s attention. Students will also be able to explore scientific methods and understand the zebra fish (stem cells) in more in debt. 

 

b)  The type of cell that I choose was the stem cells in zebrafish. 

Stem cells in zebrafish are found in the intestines, skin, bone marrow and are also found in the eyes and brain. 

 

2.)  A) The embryonic stem cells have captured the imagination of scientist and non-scientist. The zebra fish eye, all the stages of progression of the stem cells to the differentiated neuron are found near the margin of the eye in a vertebrate and contain perpetually self – renewing proliferation neuroepithelial cells. The stem cells can differentiate into specialized cells and can divide to produce more stem cells. They act as a repair system for the body replenishing adult tissue. When I get older, I would like to be a scientist so I can use the fate cells in bio medicine for curing the degeneration diseases of an ageing society.

b)   The structure of the stem cells in the zebra fish contains several populations of continuously proliferating cells in their eye and brain.

 

Image

DIAGRAM SHOWING STEM CELLS IN A ZEBRA FISH.

 

 

 

Video Review:
This is a video that shows what proteins are made up of, the reactions they undergo and how peptide bonds are formed.The secondary structures (alpha helix, beta sheet and beta turns) are shown very clearly and some properties of fibrous proteins are described such as keratin and collagen.I think this is a good video in terms of describing the secondary structures because it shows exactly how it is formed and gives a better picture rather than just reading it from a textbook.This video can can be improve by showing the other structure such as tertiary and quaternary structures.
This video was taken from youtube: http://www.youtube.com/watch?v=K5TdgMA4-dY

Viedo Review:
This is a short video that helps you to understand carbohydrates very clearly as it describes the bonding and structure of monosaccharides, disaccharides,polysaccharides, cellulose,lactose etc. It also describes energy sources and what it is built of, It tells us how sugars are form and the type of reaction it undergoes.in this video they explian ribose an deoxyribose in DNA AND RNA molecules. I think this video can be improved by giving more information on cellulose and starch but however i still find it is a good one!!!!!
This video was taken from youtube.

1)      In cells, what is the name of the organelle that gives the cell its shape and moves organelles back and forth?

 

a)      Nucleus

b)      Proteasome

c)       Cytoskeleton

d)      lysosomes

e)      cytoplasm

 

 

 

 

 

2)      There are four types of inhibitors that performs certain features such as:

1)      binds revisable to the same site

2)      binds at different site on enzyme

3)      increase in substrate concentration

4)      increase in Km

5)      undergo conformational change

 

 

From the above features which of these suits competitive inhibitor

A) 1, 2, 4

B) 3, 4, 5

C) 1, 3, 4

D) 2, 5

E) 1

 

 

 

PUBLISH PAPER 2: The topic that is been discussed: The cause of cancer revisited “mitochondrial malignancy”

 

         Oncoproteins and tumours suppressor’s proteins promote the malignant transformation of cells that affects the properties for example cells cycle regulation. Viruses as well as chemicals are accepted as commonly involved in gene mutation that encodes the cancer- causing proteins that contributes to cancer. Evidence shows that the two important additional important factors on the proliferating cells are involved in the change of the malignancy and these are stressful conditions for example lack of glucose. This promotes the process of malignant transformation when there are a low percentage of cells that escapes and overcome the cellular senescence. Stressful conditions cause the progressive increase in the chronic RDS which leads to stabilization of cells over a period of time with increased HIF- 2alpha expression that helps cells to live with increasing ROS. With cells under stressful conditions DNA mismatch causes an accumulation of the mitochondrial ROS- induced oxidative. This causes damage to the DNA. Mutated cancer- causing proteins comes back to build up the process by affecting mitochondrial processes/function. Many malignant processes involve an increase in mitochondrial ROS production and when there are some cells that survive and oxidative damage causes death. The few cells that escape with oncogenic mutation survive and then become immortalized tumours. As we know the role of the mitochondria as drivers of increasing the production of ROS. They have a potential as targets for cancer therapy.

                     There are important concerns of the mitochondrial ROS- responsible for growth and death, available evidences in the form of stressful conditions represent two major for cancer and when the  gene alteration expression is being support by Oncoproteins.

                       This information was taken from PubMed website: ABSTRACT

  http://www.ncbi.nlm.nih.gov/pubmed/20206201

Mol Aspects Med. 2010 Apr;31(2):145-70. doi: 10.1016/j.mam.2010.02.008. Epub 2010 Mar 2.

Published Paper 1: Inhibitors for controlling the mosquito-borne diseases as well as malaria (Novel selective irreversible mosquito Acetylcholinesterase).

 

 

                      It has been reported a while ago that the insect acetylcholinesterase (AchEs) may be selectively inhibited as well as irreversible by the methanethiosulfonate through insect- specific cysteine enzymes. As we know the human diseases malaria is caused by a minute organism blood sucker that is being transmitted by mosquitoes. The world malaria report in 2011 we can see that there were about 3.3 billion people that are being infected with the malaria disease and close to 216 million cases led to 655,000 deaths. Insecticides are known to contract the condition but however the insecticides are being distributed by the poisonous to humans so there is an urgent need for Novel insecticides control to keep these pests away from transmitting the disease (malaria) with the use of a lowered insecticide as well as poisonous to other species.

                      The AchE is known to be a hydrolase vital to regulate the neurotransmitter acetylcholine in mammals. This hydrolyses the acetylcholine to the bottom of the active site. The African malaria mosquito, a diseases transmitting mosquito have two AchE. Both have an insect specific cysteine that is located at the rim (active site). As we know AchE of a non-insect will have few cysteine- targeting AchE that will lowered the off-species toxicity. The developments of methanethiosulfonate have been formed because of the following reason that is selectively and irreversibly inhibit insect APAchEs.

                     Cysteine-targeting inhibitor has enough affinity for active site to build up a concentration all around cys 286 that is very high to set off the sulphur –aromatic interactions. They have flexibility for covalent bonds. 

      This information was taken from pub med website. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3545233/

PMCID: 

PMC3545233

ArticlePubReaderPDF–1.7MSupplementary Material

 

 

Image