I am a pericardial cell in the model organism D. Melanogaster and I reside in the heart (dorsal vessel) of this organism.
My origin begins not at the very beginning but during the first few days of my organism’s development. In Drosophila the embryo is an undifferentiated cell and thus my beginning. The mesoderm gives rise to the heart as well as somatic and visceral muscles through a very complex process during the life cycle. A series of genes are also used during this process.
Fig 1: Life cycle of Drosophila.
According to Thomas B. Brody (2006), about 180-189 minutes after fertilisation (stage 6-7), gastrulation occurs to form the mesoderm (where I come from!), endoderm and ectoderm. During early stage 12 onward heart (dorsal vessel) development begins from specialisations of the mesoderm into its destined tissues.
Fig 2: Mesoderm in Drosophila Melanogaster.
From stage 13 the primordium of the dorsal vessel moves dorsally with the folded ectoderm and two rows of cells which have different characteristics are formed: the cardioblasts that form the dorsal vessel proper and the pericardial cells (that’s ME!) that line the dorsal vessel on either side.
Fig 3: A look at the formation of the heart ( dorsal vessel) in drosophila.
Drosophila heart development begins during embryonic stage 13 by specification of two contralateral rows of cardiogenic mesoderm and formation of cardioblasts. Cardioblasts migrate towards the midline at stage 13–14 and form a simple linear closed tube with a central lumen by stage 16–17, subsequently differentiating into more mature cardiomyocytes. The pericardial cells line the sides of the cardioblasts.
As a pericardial cell I have a very important job within my organism i.e to protect it from harmful substances that may be in the haemolymph. My role is to detoxify the haemolymph from complex and toxic compounds that might be present. My special organelles called lysosomes break down these compounds so they can be used in my cytoplasm without harming my organism. Isn’t it EXCITING!!!
Fig. 4. Left: highly ordered structure of the Drosophila heart is well suited to identify even subtle differences in morphology (dMef2-positive muscle nuclei in blue; pericardin-positive pericardial cell membranes in brown surrounding the blue myocardial cells). Right: schematic cross-section through the heart illustrating its simple cellular arrangement
This is my fate! This is my destiny. This is what I want to be when I become a developed cell.
I am a large cell that run along the sides of the the dorsal vessel on either side. I contain a series of organelles within my cell that would help me function on a daily basis; lysosomes (mentioned above. I have many of these because they are important to my function), vacuole, golgi apparatus which processes and distributes molecules, rough ER a site for protein synthesis, smooth ER the site for lipid and carb metabolism, mitochondria- my power house, ribosomes- protein synthesis and most importantly my nucleus which houses my DNA, it is also my control center.
So you see my fellow bloggers: I am a Pericardial cell.