DASAR-DASAR

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DASAR-DASAR MORFOGENESIS
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Morfogenesis

• Proses biologis yang menyebabkan organisme
  berkembang bentuknya
• Aspek dasar dari bioper morfogenesis, tumbuh dan
  diferensiasi
• Proses pengaturan tersebut terjadi selama
  perkembangan embrio menjadi organisme dewasa

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POLA PERKEMBANGAN
Pola perkembangan stadium I
Pola perkembangan stadium II
Pengaturan waktu Intensitas masa
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PERKEMBANGAN

1. Perkembangan sebelum lahir/menetas
2. Urutan peristiwa morfogenetik awal
3. Mekanisme pengaturan ? organisasi dari kompleks
   sampai tingkat molekular

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Sel ? Jaringan ? Organ Organisme
Sistem organ Pencernaan makanan Saraf Pernafasan
Reproduksi Transportasi, dll
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• TERDIRI DARI 2 PERIODE
• PERTUMBUHAN ANTARA
• PERTUMBUHAN AKHIR
• 1. PERIODE PERTUMBUHAN ANTARA
• TERJADI TRANSFORMASI DAN DIFERENSIASI
  BAGIAN-BAGIAN TUBUH EMBRIO DARI BENTUK PRIMITIF,
  SEHINGGA BENTUK YANG DEFINITIF SUATU SPESIES
  (BENTUK KATAK, AYAM ATAU SAPI, TINGKAT BERUDU /
  LARVA)

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• 2. PERIODE PERTUMBUHAN AKHIR
• PENYELESAIAN BENTUK DEFINITIF MENJADI BENTUK
  INDIVIDU (PERTUMBUHAN JENIS KELAMIN, WAJAH
  INDIVIDU YANG KHAS)
• PADA AVES, REPTIL DAN MAMALIA
• BATAS ANTARA KEDUA PERIODE TERSEBUT TIDAK
  JELAS

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• Morfogenesis diinduksi oleh
• hormon
• Kimia lingkungan (toxic chemicals) dari polutan
• Induksi stres mekanik
• Morfogenesis terjadi di
• Embrio
• Organisme dewasa
• Kultur sel
• Sel tumor

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Dasar-dasar Molekular

• Molekul yang penting selama morfogenesis
• Molekul morfogen, ciri
• Morfogen ?
• bentuk cair,
• dapat difusi dan pembawa sinyal untuk pengaturan
  diferensiasi sel,
• dapat mengikat reseptor protein spesifik,
• protein faktor transkipsi untuk mendeterminasi
  sel melalui interaksi dengan DNA,
• merupakan molekul yang mengatur perlekatan sel,
  misal
• selama gastrulasi,
• kelompok stem sel,
• migrasi, dan
• pembentukan jaringan organ baru

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Dasar selular

• Sel hidup (merah) banyak mengandung E-cadherin
  (molekul perlekatan sel (cell adhesion molecules,
  CAMs), sel hidup (hijau) sedikit Live cells were
  stained with either Dil (red) or DiO (green). The
  red cells were genetically altered and express
  higher levels of E-cadherin (). than the green
  cells.
• After labeling, the two populations of cells were
  mixed and cultured together allowing the cells to
  form large multi-cellular mixed aggregates.
• Individual cells are less than 10 ?m in diameter

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• Morphogenesis arises because of changes in the
  cellular structure or how cells interact in
  tissues
• The ability of cells to do this comes from
  differential cell adhesion.
• Two well-studied types of cells that sort out are
  epithelial cells and mesenchyme cells
• During embryonic development cellular
  differentiation (mesenchymal cells become
  epithelial cells)
• Following epithelial-mesenchymal transition,
  cells can migrate away from an epithelium and
  then associate with other similar cells in a new
  location.

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Adhesion

• During embryonic development ? cells sort out in
  different layers due to differential adhesion
• The same cell-to-cell adhesion molecules separate
  from cells that have different adhesion
  molecules.
• Cells sort ? differences in adhesion between the
  cells, so two populations of cells ? different
  levels

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• In culture cells ?the strongest adhesion move to
  the center of a mixed aggregates of cells
• The molecules responsible for adhesion are are
  cadherins
• There are dozens of different cadherins that are
  expressed on different cell types.
• Cadherins bind to other cadherins in a
  like-to-like manner E-cadherin (found on many
  epithelial cells) binds to other E-cadherin
  molecules.
• Mesenchymal cells usually express other cadherin
  types such as N-cadherin.

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Extracellular matrix

• The extracellular matrix (ECM) ? separating
  tissues, providing structural support or
  providing a structure for cells to migrate on
• ECM molecules collagen, laminin, and fibronectin
  are secreted and assembled into sheets, fibers,
  and gels.
• Multisubunit transmembrane receptors called
  integrins are used to bind to the ECM.

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• Integrins bind
• extracellularly to fibronectin, laminin, or other
  ECM components
• intracellularly to microfilament-binding proteins
  ?-actinin and talin to link the cytoskeleton with
  the outside.
• Integrins also serve as receptors to trigger
  signal transduction cascades when binding to the
  ECM

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MORPHOGENESIS
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TERIMA KASIH ATAS PERHATIANNYA
alfiahayati_at_unair.ac.id