Human proteome contains 25 selenoproteins. Selenocysteine, sometimes called the “twenty-first amino acid,”

TLS Online TPP Program

#Id: 3855

#Unit 5. Developmental Biology

Dictyostelia (social amoebas)

solitary haploid amoebae live on decaying logs, eating bacteria and reproducing by binary fission.

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#Unit 5. Developmental Biology

Dictyostelium can utilize one of three survival strategies when food starvation-

(1) Microcyst formation, favoured in dark & wet conditions, or ammonia levels are high.
(2) Zygote formation, favoured in dark & wet conditions, & triggered by ethylene produced by the cells.
(3) Cell aggregation & differentiation

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#Unit 5. Developmental Biology

Phosphorylation of RegA is mediated by sensor histidine kinases/phosphatases which either phosphorylate or dephosphorylate themselves on a histidine residue when a signal molecule binds to their sensor domain.

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#Id: 3858

#Unit 5. Developmental Biology

Cell Aggregation & Differentiation is common to all Dictyostelids.
It consists of an interconnected programme of cell movement and cell differentiation.

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#Unit 5. Developmental Biology

The binding of ammonia to the sensor domain of DhkC leads to the activation of its histidine kinase activity and to the autophosphorylation of a DhkC histidine residue.

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#Id: 3860

#Unit 5. Developmental Biology

The phosphoryl group is transferred,

From histidine residue of DhkC  aspartate of DhkC histidine in phospho-transfer intermediate RdeA aspartate of RR of RegA