97 research outputs found
Chlorophyll-deficient mutants of Chlamydomonas reinhardtii that accumulate magnesium protoporphyrin IX
Two Chlamydomonas reinhardtii mutants defective in CHLM encoding Mg-protoporphyrin IX methyltransferase (MgPMT) were identified. The mutants, one with a missense mutation (chlM-1) and a second mutant with a splicing defect (chlM-2), do not accumulate chlorophyll, are yellow in the dark and dim light, and their growth is inhibited at higher light intensities. They accumulate Mg-protoporphyrin IX (MgProto), the substrate of MgPMT and this may be the cause for their light sensitivity. In the dark, both mutants showed a drastic reduction in the amounts of core proteins of photosystems I and II and light-harvesting chlorophyll a/b-binding proteins. However, LHC mRNAs accumulated above wild-type levels. The accumulation of the transcripts of the LHC and other genes that were expressed at higher levels in the mutants during dark incubation was attenuated in the initial phase of light exposure. No regulatory effects of the constitutively 7- to 18-fold increased MgProto levels on gene expression were detected, supporting previous results in which MgProto and heme in Chlamydomonas were assigned roles as second messengers only in the transient activation of genes by light
NORADRENERGIC AND CHOLINERGIC MECHANISMS RESPONSIBLE FOR THE GAIN REGULATION OF VESTIBULOSPINAL REFLEXES
Effects of kainic acid lesions of lateral reticular nucleus on posture and reflex movements
EFFECTS OF PASSIVE FLEXION OF THE FOREPAW ON THE RESPONSE GAIN OF LIMB EXTENSORS TO SINUSOIDAL STIMULATION OF LABYRINTH RECEPTORS
INJECTIONS OF A BETA-ADRENERGIC ANTAGONIST IN PONTINE RETICULAR STRUCTURES MODIFY THE GAIN OF VESTIBULOSPINAL REFLEXES IN DECEREBRATE CATS
EFFECTS OF MICROINJECTION OF A CHOLINERGIC AGONIST INTO THE LOCUS-COERULEUS ON THE GAIN OF VESTIBULOSPINAL REFLEXES IN DECEREBRATE CATS
PONTINE RETICULAR ORIGIN OF CHOLINERGIC EXCITATORY AFFERENTS TO THE LOCUS-COERULEUS CONTROLLING THE GAIN OF VESTIBULOSPINAL AND CERVICOSPINAL REFLEXES IN DECEREBRATE CATS
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