Iron-Sulfur World in Aerobic and Hyperthermoacidophilic Archaea Sulfolobus

The general importance of the Fe-S cluster prosthetic groups in biology is primarily attributable to specific features of iron and sulfur chemistry, and the assembly and interplay of the Fe-S cluster core with the surrounding protein is the key to in-depth understanding of the underlying mechanisms. In the aerobic and thermoacidophilic archaea, zinc-containing ferredoxin is abundant in the cytoplasm, functioning as a key electron carrier, and many Fe-S enzymes are produced to participate in the central metabolic and energetic pathways. De novo formation of intracellular Fe-S clusters does not occur spontaneously but most likely requires the operation of a SufBCD complex of the SUF machinery, which is the only Fe-S cluster biosynthesis system conserved in these archaea. In this paper, a brief introduction to the buildup and maintenance of the intracellular Fe-S world in aerobic and hyperthermoacidophilic crenarchaeotes, mainly Sulfolobus, is given in the biochemical, genetic, and evolutionary context

A stable intermediate product of the archaeal zinc-containing 7Fe ferredoxin from Sulfolobus sp. strain 7 by artificial oxidative conversion

AbstractIrreversible conversion of the purified zinc-containing 7Fe ferredoxin from the thermoacidophilic archaeon Sulfolobus sp. strain 7 was found to occur under aerobic conditions at pH 5.0 and at 4°C. This process accompanied a substantial increase of the electron paramagnetic resonance signal attributed to a [3Fe-4S]1+ cluster, and the converted form containing ∼6 Fe/Zn (mol/mol) had a net charge different from that of the native 7Fe ferredoxin. These data provide evidence for the formation of a stable intermediate product of the archaeal ferredoxin having two [3Fe-4S] clusters and a zinc center by artificial oxidative degradation. This further explains the discrepancy that a zinc center and two [3Fe-4S] clusters (but not a zinc center and one [3Fe-4S] cluster plus one [4Fe-4S] cluster) are observed in the crystal structure at pH 5.0

Site specific regulation in the kidney of endothelin and its receptor subtypes by cyclosporine

Site selective regulation in the kidney of endothelin and its receptor subtypes by cyclosporine. Endothelin (Et) has been suggested by us and others to play a role in glomerular dysfunction that characterizes cyclosporine (Cs)-associated nephrotoxicity. Since Et exerts its actions through at least two receptor subtypes, and because these receptor subtypes have particular distributions in the renal parenchyma, we investigated changes in mRNA expression for Et and its receptor subtypes in glomeruli and medulla of rats treated with Cs. Polymerase chain reaction coupled with reverse transcription (RT-PCR) method was used to assess prepro-Et-1, type A (EtA) and type B (EtB) receptor mRNA at 1, 3, 6, and 24 hours after Cs (20 mg/kg body wt i.v.). Results were normalized to the expression of β-actin as an internal standard. Compared with control rats, glomerular mRNA expression for prepro-Et-1 was not affected by Cs. Similarly, Cs did not significantly change the glomerular mRNA expression of either EtA or EtB receptor subtypes. By contrast, in the medulla there was a marked and persistent increase in the expression for prepro-Et-1 and the EtB receptor subtype: prepro-Et-1 at 1, 3, 6, and 24 hours was 336 ± 61, 295 ± 65, 339 ± 73,440 ± 123% of controls, respectively (P < 0.05 compared with controls at each time point). The EtB receptor mRNA at 1, 3, 6, 24 hours was 164 ± 22, 157 ± 15, 148 ± 14, 116 ± 18% (compared with controls, P < 0.01 at 3hr and P < 0.05 at 1 and 6 hr), while the mRNA expression for EtA was not affected by Cs treatment. These results demonstrate that, in vivo, Cs selectively modulates renal mRNA expression for Et peptide and one of its receptor subtypes. Furthermore, the modulation is site specific. These changes are most conspicuous in the renal medulla, such that mRNA expression for prepro-Et-1 and EtB increases and remains elevated for at least six hours after Cs administration. These alterations may contribute to the vasospastic as well as proliferative abnormalities which characterize Cs nephrotoxicity

Activities of bone morphogenetic proteins in prolactin regulation by somatostatin analogs in rat pituitary GH3 cells

Involvement of the pituitary BMP system in the modulation of prolactin (PRL) secretion regulated by somatostatin analogs, including octreotide (OCT) and pasireotide (SOM230), and a dopamine agonist, bromocriptine (BRC), was examined in GH3 cells. GH3 cells are rat pituitary somato-lactotrope tumor cells that express somatostatin receptors (SSTRs) and BMP system molecules including BMP-4 and -6. Treatment with BMP-4 and -6 increased PRL and cAMP secretion by GH3 cells. The BMP-4 effects were neutralized by adding a BMP-binding protein Noggin. These findings suggest the activity of endogenous BMPs in augmenting PRL secretion by GH3 cells. BRC and SOM230 reduced PRL secretion, but OCT failed to reduce the PRL level. In GH3 cells activated by forskolin, BRC suppressed forskolin-induced PRL secretion with reduction in cAMP levels. OCT did not affect forskolin-induced PRL level, while SOM230 reduced PRL secretion and PRL mRNA expression induced by forskolin. BMP-4 treatment enhanced the reducing effect of SOM230 on forskolin-induced PRL level while BMP-4 did not affect the effects of OCT or BRC. Noggin treatment had no significant effect on the BRC actions reducing PRL levels by GH3 cells. However, in the presence of Noggin, OCT elicited an inhibitory effect on forskolin-induced PRL secretion and PRL mRNA expression, whereas the SOM230 effect on PRL reduction was in turn impaired. It was further found that BMP-4 and -6 suppressed SSTR-2 but increased SSTR-5 mRNA expression of GH3 cells. These findings indicate that Noggin rescues SSTR-2 but downregulates SSTR-5 by neutralizing endogenous BMP actions, leading to an increase in OCT sensitivity and a decrease in SOM230 sensitivity of GH3 cells. In addition, BMP signaling was facilitated in GH3 cells treated with forskolin. Collectively, these findings suggest that BMPs elicit differential actions in the regulation of PRL release dependent on cellular cAMP-PKA activity. BMPs may play a key role in the modulation of SSTR sensitivity of somato-lactotrope cells in an autocrine/paracrine manner

Capillary Electrophoretic Characterization of Carbon Nanodots Prepared from Glutamic Acid in an Electric Furnace

Carbon nanodots (CNDs) prepared from glutamic acid or glutathione in an electric furnace were characterized by capillary electrophoresis. Two major peaks were detected in the electropherograms by capillary zone electrophoresis, corresponding to anionic and less-charged CNDs. The effective electrophoretic mobility of the anionic CND formed from glutamic acid was almost identical over neutral to weakly alkaline pH range, and the CND would not contain significant amount of amino group. On the other hand, the effective electrophoretic mobility tended to decrease with decreasing pH at weakly acidic pH conditions, suggesting the functional groups of carboxylate moiety on the anionic CNDs. Dodecyl sulfate ion was added in the separation buffer to give anionic charge to the less-charged CND by adsorption. However, the anionic charge induced was little, and the dodecyl sulfate ion was not likely adsorbed on the less-charged CND and the CND would be hydrophilic

Two-dimensional pulsed electron spin resonance characterization of 15N-labeled archaeal Rieske-type ferredoxin

AbstractTwo-dimensional electron spin-echo envelope modulation (ESEEM) analysis of the uniformly 15N-labeled archaeal Rieske-type [2Fe–2S] ferredoxin (ARF) from Sulfolobus solfataricus P1 has been conducted in comparison with the previously characterized high-potential protein homologs. Major differences among these proteins were found in the hyperfine sublevel correlation (HYSCORE) lineshapes and intensities of the signals in the (++) quadrant, which are contributed from weakly coupled (non-coordinated) peptide nitrogens near the reduced clusters. They are less pronounced in the HYSCORE spectra of ARF than those of the high-potential protein homologs, and may account for the tuning of Rieske-type clusters in various redox systems

Hematological studies on iron- and folate-requirements in pregnancy

Hematological changes and serum iron, vitamin B12 and folate levels after administration of iron plus folic acid were com· pared with changes and levels after supplement of iron alone in 100 pregnant women. No hematological benefits by adding folic acid was revealed. It is concluded that folic acid deficiency in pregnant women is mild and routine supplementation of folic acid is not necessary except for proved cases of folate deficiency. As to the reason why folic acid deficiency is so mild and megaloblastic anemia is so rare in Japan, uniformity of dietary habits, i. e. boiled rice as basic food, was discussed.</p

Botulinum toxin type A in post-stroke lower limb spasticity: a multicenter, double-blind, placebo-controlled trial

Lower limb spasticity in post-stroke patients can impair ambulation and reduces activities of daily living (ADL) performance of patients. Botulinum toxin type A (BoNTA) has been shown effective for upper limb spasticity. This study assesses the treatment of lower limb spasticity in a large placebo-controlled clinical trial. In this multicenter, randomized, double-blind, parallel-group, placebo-controlled study, we evaluate the efficacy and safety of one-time injections of botulinum toxin type A (BoNTA) in Japanese patients with post-stroke lower limb spasticity. One hundred twenty patients with lower limb spasticity were randomized to a single treatment with BoNTA 300 U or placebo. The tone of the ankle flexor was assessed at baseline and through 12 weeks using the Modified Ashworth Scale (MAS). Gait pattern and speed of gait were also assessed. The primary endpoint was area under the curve (AUC) of the change from baseline in the MAS ankle score. Significant improvement in spasticity with BoNTA 300 U was demonstrated by a mean difference in the AUC of the change from baseline in the MAS ankle score between the BoNTA and placebo groups (−3.428; 95% CIs, −5.841 to −1.016; p = 0.006; t test). A significantly greater decrease from baseline in the MAS ankle score was noted at weeks 4, 6 and 8 in the BoNTA group compared to the placebo group (p < 0.001). Significant improvement in the Clinicians Global Impression was noted by the investigator at weeks 4, 6 and 8 (p = 0.016–0.048, Wilcoxon test), but not by the patient or physical/occupational therapist. Assessments of gait pattern using the Physician’s Rating Scale and speed of gait revealed no significant treatment differences but showed a tendency towards improvement with BoNTA. No marked difference was noted in the frequency of treatment-related adverse events between BoNTA and placebo groups. This was the first large-scale trial to indicate that BoNTA significantly reduced spasticity in lower limb muscles