Dark grown mycelial cells of Neurospora crassa bearing mutant genes crisp-I or frost and having a decreased level of cyclic adenosine 3,5-monophosphate contained more carotenoid pigments than the cells with wild alleles of these genes. A transient decrease of the cyclic AMP occurred following photoinduction of carotenoid synthesis during its lag-period. Its intensity correlated with the increase of carotenoid pigment level due to photoinduction. No correlation in the content of cyclic guanosine 5-phosphate with both constitutive level of carotenoids and its photoinduced increase was observed. 相似文献
Four types of anomalous conjugation were documented in Stylonychia mytilus. Type I pairs were formed between mates of different sizes. These pairs exhibited an abnormal site of fusion in at least one of the mates, and the mates might face each other ventrally throughout conjugation instead of the normal side-by-side position. Type I pairs underwent sexual nuclear development and proceeded with the first cortical reorganization as in normal conjugants. Type II involved pairing at the anterior ends of mates with ventral surfaces facing the same direction. These pairs also underwent sexual nuclear development. Hence, aberrant orientation of the mates, and also ectopic sites of cytoplasmic fusion, if extensive, would permit sexual development. Type III pairs were united ventral-to-ventral with their anterior-left sides at the adoral zone of membranelles, and remained as such throughout conjugation. In these pairs, nuclear and cortical events were typical of the asexual development of physiological reorganization. In Type IV pairs, one mate of the pair possessed a fission furrow and developed two sets of ciliature typical of binary fission, while the other mate might undergo physiological reorganization or binary fission. Type III and Type IV pairs thus reveal the asexual state of early conjugants, which can pursue either one of the two modes of asexual cortical reorganization; these cases reinforce the notion of overlap of asexual and sexual cycles during conjugation of hypotrichs. Spontaneous autogamy was documented for the first time for this genus. The autogamonts proceeded with nuclear development and with the first cortical reorganization. Some probably underwent second and third reorganizations, as in conjugants, but accompanied by abnormalities, particularly in the stages beyond fertilization. Post-autogamous clones were nonviable except for one dubious case. 相似文献
Mutations in the CLN3 gene lead to so far an incurable juvenile-onset neuronal ceroid lipofuscinosis (JNCL) or Batten disease that starts at the age of 4–6 years with a progressive retinopathy leading to blindness. Motor disturbances, epilepsy and dementia manifest during several following years. Most JNCL patients carry the same 1.02-kb deletion in the CLN3 gene, encoding an unusual transmembrane protein, CLN3 or battenin.
Results
Based on data of genome-wide expression profiling in CLN3 patients with different rate of the disease progression [Mol. Med., 2011, 17: 1253–1261] and our bioinformatic analysis of battenin protein-protein interactions in neurons we propose that CLN3 can function as a molecular chaperone for some plasma membrane proteins, being crucially important for their correct folding in endoplasmic reticulum. Changes in spatial structure of these membrane proteins lead to transactivation of the located nearby receptors. Particularly, CLN3 interacts with a subunit of Na/K ATPase ATP1A1 which changes its conformation and activates the adjacent epidermal growth factor receptor (EGFR). As a result, a large amount of erroneously activated EGFR generates MAPK signal cascades (ERK1/ERK2, JNKs and p38) from cell surface eventually causing neurons’ death.
Conclusions
Molecular mechanism of the juvenile form of Batten disease (JNCL), which is based on the excessive activation of signaling cascades in a time of the radical increase of neuronal membranes’ area in the growing brain, have been proposed and substantiated. The primary cause of this phenomenon is the defective function of the CLN3 protein that could not act properly as molecular chaperone for some plasma membrane proteins in the endoplasmic reticulum. The incorrect three-dimensional structure of at least one such protein, ATP1A1, leads to unregulated spontaneous and repetitive activation of the SRC kinase that transactivates EGFR with the subsequent uncontrolled launch of various MAPK cascades. Possible ways of treatment of patients with JNCL have been suggested.
Reviewers
This article was reviewed by Konstantinos Lefkimmiatis, Eugene Koonin and Vladimir Poroikov.
Correlation between morphology and function in the hippocampus and hypothalamus was studied by electrophysiological and morphological techniques. Single unit responses were recorded extracellularly in the arcuate and medial preoptic nuclei of the hypothalamus to application of single stimuli to the hippocampus. Phasic responses and primary inhibition predominated in the arcuate nucleus, whereas both phasic and tonic responses were observed in the medial preoptic nucleus. In the morphological experiments horseradish peroxidase was injected into the same region of the hippocampus. Stained cells were found in the nuclei of the mammillary body, mediobasal hypothalamus, and medial preoptic nucleus. Groups of stained neurons were discovered at the periphery of the ventro- and dorsomedial and also in the lateral and mammillary nuclei of the hypothalamus. Besides fusiform and triangular neurons, reticular neurons also were found in all structures except the medial mammillary nucleus. The results are discussed from the standpoint of interaction between hypothalamus and hippocampus.A. A. Zhdanov State University, Leningrad. Translated from Neirofiziologiya, Vol. 11, No. 5, pp. 427–434, September–October, 1979. 相似文献
In situ RNA hybridization and immunocytochemistry were used to establish the cellular distribution of monoterpenoid indole alkaloid biosynthesis in Madagascar periwinkle (Catharanthus roseus). Tryptophan decarboxylase (TDC) and strictosidine synthase (STR1), which are involved in the biosynthesis of the central intermediate strictosidine, and desacetoxyvindoline 4-hydroxylase (D4H) and deacetylvindoline 4-O-acetyltransferase (DAT), which are involved in the terminal steps of vindoline biosynthesis, were localized. tdc and str1 mRNAs were present in the epidermis of stems, leaves, and flower buds, whereas they appeared in most protoderm and cortical cells around the apical meristem of root tips. In marked contrast, d4h and dat mRNAs were associated with the laticifer and idioblast cells of leaves, stems, and flower buds. Immunocytochemical localization for TDC, D4H, and DAT proteins confirmed the differential localization of early and late stages of vindoline biosynthesis. Therefore, we concluded that the elaboration of the major leaf alkaloids involves the participation of at least two cell types and requires the intercellular translocation of a pathway intermediate. A basipetal gradient of expression in maturing leaves also was shown for all four genes by in situ RNA hybridization studies and by complementary studies with dissected leaves, suggesting that expression of the vindoline pathway occurs transiently during early leaf development. These results partially explain why attempts to produce vindoline by cell culture technology have failed. 相似文献
The data on the enzyme activity of paleosoils of archaeological sites are given. It is shown that the activity of phosphatases and urease in soils of ancient settlements is significantly higher than in modern soils: 1.5–2.0 times for urease and 7–15 times for phosphatase in some cultural layers of the Bronze Age. This is related to a large amount of organic material (garbage, rubbish, excrement, and urea), which entered the soil in ancient times and stimulated soil microorganisms to produce a greater amount of enzymes, whose high activity has been preserved for 4000 years. The location of the enzymes was determined by soil fumigation using chloroform and activation of extracellular enzymes by glycine. The release of intracellular enzymes as a result of fumigation caused a significant increase in phosphatase activity in modern soils and soils of ancient settlements in contrast to the virgin paleosoil of the Bronze Age. The treatment by glycine exerted a smaller effect on the activity of phosphatases, but caused a significant increase in urease activity. This may indicate the predominating extracellular localization of urease in paleosoils of ancient settlements, while phosphatase is characterized by both extra- and intracellular localization.
We have summarized the results of psychophysiological studies in schoolchildren aged 10–12 years with cerebral functional disturbances of hypoxic-ischemic or traumatic origin with learning difficulties. We have differentiated three types of disintegration of ultraslow information-controlling systems that reflect specific disturbances in the interaction of cortical-brainstem, limbic-reticular, and suprasegmental mechanisms of regulation of the wakefulness level and are characterized by emotional and cognitive disturbances typical of each type of disintegration. Adolescents with moderately and strongly decreased resistance to transitory hypoxia differed in psychological and psychophysiological effects of corrective and recovery therapy, which included transcranial micropolarization (TCMP) and psychological-pedagogical sessions during and between TCMP sessions and during the intervals between repeated TCMP courses. We discuss the psychophysiological mechanisms of the corrective effect of low-intensity direct currents with parameters close to the native ultraslow processes of the brain and the body systems regulated by these parameters. 相似文献