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The diurnal variation of TRH concentrations in different parts of hypothalamus was studied in 80 male rats, which were killed in groups of 5 at 3 h intervals. The hypothalamus was dissected into three parts: I) medial basal hypothalamus (MBH), II) anterior hypothalamus, and III) dorsal hypothalamus. Anterior pituitary and serum TSH concentrations were also measured. TRH concentrations were higher in MBH than in the other parts of the hypothalamus: at night 300–450 pg/mg of wet weight of tissue. When the lights were turned on, MBH-TRH levels began to decrease, reaching a nadir of 210 pg/mg at 12 noon. After 15 h, MBH-TRH levels began to increase again. The changes in TRH levels in anterior hypothalamus were usually opposite to those in MBH (r = ?0.6185). Serum TSH levels were about 800 ng/ml during the day and were decreased to about one half of these levels when the lights were turned off. Serum TSH levels were positively correlated with anterior hypothalamic TRH levels (r = 0.6457) and inversely correlated with MBH-TRH levels (r = ?0.7747). Anterior pituitary TSH levels showed small but statistically insignificant variations. In conclusion, there were statistically interrelated diurnal rhythms in anterior hypothalamic and MBH-TRH levels and serum TSH concentrations.  相似文献   
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Summary The movement and transport of material between intranuclear dense particles, the chromatoid body and the Golgi complex have been studied in early spermatids of the rat. The analyses involved observation of living accurately identified cells, time-lapse cinemicrography and electron microscopy.The chromatoid body establishes transient contacts with intranuclear material during early spermiogenesis. The chromatoid body also makes contacts with the Golgi complex. It is suggested that the chromatoid body receives material from the nucleus during the postmeiotic period and participates in the early formation of the acrosomic system.This work was supported by the Finnish National Research Council for Medical Sciences. The authors are grateful to Mrs. Marita Aaltonen and Mrs. Raija Andersen for their skilful technical assistance  相似文献   
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Formaldehyde dehydrogenase (EC 1.2.1.1) and formate dehydrogenase (EC 1.2.1.2) have been isolated in pure form from pea seeds by a rapid procedure which employs column chromatographies on 5′-AMP-Sepharose, Sephacryl S-200, and DE32 cellulose. The apparent molecular weights of formaldehyde and formate dehydrogenases are, respectively, 82,300 and 80,300 by gel chromatography, and they both consist of two similar subunits. The isoelectric point of formaldehyde dehydrogenase is 5.8 and that of formate dehydrogenase is 6.2. The purified formate dehydrogenase gave three corresponding protein and activity bands in electrophoresis and isoelectric focusing on polyacrylamide gel whereas formaldehyde dehydrogenase gave only one band. Formaldehyde dehydrogenase catalyzes the formation of S-formylglutathione from formaldehyde, and glutathione. Formate dehydrogenase can, besides formate, also use S-formylglutathione and two other formate esters as substrates. S-Formylglutathione has a lower Km value (0.45 mm) than formate (2.1 mm) but the maximum velocity of S-formylglutathione is only 5.5% of that of formate. Pea extracts also contain a highly active S-formylglutathione hydrolase which has been separated from glyoxalase II (EC 3.1.2.6) and partially purified. S-Formylglutathione hydrolase is apparently needed between formaldehyde and formate dehydrogenases in the metabolism of formaldehyde in pea seeds, in contrast to what was recently reported for Hansenula polymorpha, a yeast grown on methanol.  相似文献   
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The Fortilin (also known as TCTP) in Penaeus monodon (PmFortilin) and Fortilin Binding Protein 1 (FBP1) have recently been shown to interact and to offer protection against the widespread White Spot Syndrome Virus infection. However, the mechanism is yet unknown. We investigated this interaction in detail by a number of in silico and in vitro analyses, including prediction of a binding site between PmFortilin/FBP1 and docking simulations. The basis of the modeling analyses was well-conserved PmFortilin orthologs, containing a Ca(2+)-binding domain at residues 76-110 representing a section of the helical domain, the translationally controlled tumor protein signature 1 and 2 (TCTP_1, TCTP_2) at residues 45-55 and 123-145, respectively. We found the pairs Cys59 and Cys76 formed a disulfide bond in the C-terminus of FBP1, which is a common structural feature in many exported proteins and the "x-G-K-K" pattern of the amidation site at the end of the C-terminus. This coincided with our previous work, where we found the "x-P-P-x" patterns of an antiviral peptide also to be located in the C-terminus of FBP1. The combined bioinformatics and in vitro results indicate that FBP1 is a transmembrane protein and FBP1 interact with N-terminal region of PmFortilin.  相似文献   
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Dieback of the terminal shoot and consequently bushy growth induced by boron deficiency have been reported widely throughout the world in several tree species. Recently, similar growth damage was documented in half of the young spruce stands in eastern Finland. To clarify the role of B deficiency, the light microscopic structure of emerging buds and of developing and previous-year needles of mature Norway spruce (Picea abies L. Karst.) from damaged (D stand), partly damaged (PD stand) and healthy (H stand) stands were analysed. The samples, on which needle nutrient concentrations were also determined, were taken seven times between early spring (April) and early winter (November). Cell death characterized by precipitation of the cell content, possibly due to the release of tannins after membrane rupture, was seen in the apex of emerging buds, and this led to fatal damage in about half of the buds in the trees from the D stand, where the needle B concentration was well below the deficiency level of 4–5 mg kg−1. Furthermore, an increase in living cells that accumulated tannins in the vacuoles, which is a common stress and/or defense reaction, was found in the primordial shoots of buds and in the differentiating needles in the PD and D stands. The increase in the areas of the central cylinder and of the xylem found in the needles indicate structural plasticity during needle differentiation to drought. The time frame for bud emergence from late May up to mid-September means that an adequate B supply is necessary throughout the summer in order to avoid fatal bud damage and thus bushy growth of the trees.  相似文献   
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Phylogeny and expression of carbonic anhydrase-related proteins   总被引:1,自引:0,他引:1  

Background  

Carbonic anhydrases (CAs) are found in many organisms, in which they contribute to several important biological processes. The vertebrate α-CA family consists of 16 subfamilies, three of which (VIII, X and XI) consist of acatalytic proteins. These are named carbonic anhydrase related proteins (CARPs), and their inactivity is due to absence of one or more Zn-binding histidine residues. In this study, we analyzed and evaluated the distribution of genes encoding CARPs in different organisms using bioinformatic methods, and studied their expression in mouse tissues using immunohistochemistry and real-time quantitative PCR.  相似文献   
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