Nitrogenase Fe protein-like Fe–S cluster is conserved in L-protein (BchL) of dark-operative protochlorophyllide reductase from Rhodobacter capsulatus

AbstractDark-operative protochlorophyllide reductase (DPOR) in bacteriochlorophyll biosynthesis is a nitrogenase-like enzyme consisting of L-protein (BchL-dimer) as a reductase component and NB-protein (BchN–BchB-heterotetramer) as a catalytic component. Metallocenters of DPOR have not been identified. Here we report that L-protein has an oxygen-sensitive [4Fe–4S] cluster similar to nitrogenase Fe protein. Purified L-protein from Rhodobacter capsulatus showed absorption spectra and an electron paramagnetic resonance signal indicative of a [4Fe–4S] cluster. The activity quickly disappeared upon exposure to air with a half-life of 20s. These results suggest that the electron transfer mechanism is conserved in nitrogenase Fe protein and DPOR L-protein

Structure of protochlorophyllide reductase reveals a mechanism for greening in the dark

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Elevated Expression of Pyrimidine Nucleoside Phosphorylase (PyNPase) in Renal Cell Carcinoma Tissue

Background: Pyrimidine nucleoside phosphorylase (PyNPase) is an enzyme that converts 5\u27-deoxy-5-fluorouridine to 5- fluorouracil. PyNPase is identical to platelet-derived endothelial cell growth factor (PD-ECGF), and has angiogenic activity. In the present study of PyNPase activity in renal cell carcinoma, we tested for correlation between PyNPase activity and tumor extension, tumor proliferation and clinical characteristics. Methods: Samples of tumor tissue and non-tumor tissue were obtained from 10 renal cell carcinoma patients who underwent radical nephrectomy. These samples were examined, and PyNPase activity of the tissues was assayed. Results: PyNPase activity was significantly higher in renal cancer tissue than in normal tissue (p<0.01), and in immunohistochemical assays PyNPase was strongly stained in the cytoplasm of renal cancer cells. However, there were no significant correlation between PyNPase activity and tumor extension, according to the results of histopathological examination and evaluation of vascularity of renal cancer tumor tissue. Conclusion: In this study, we did not observe correlation between PyNPase activity and renal cancer extension and proliferation. However, the present data suggest that pyrimidine-class drugs may be useful against renal cell carcinoma, because PyNPase activity is significantly higher in renal cancer tissue than in normal tissue

Upregulation of CA 19-9 in the Mouse Kidney Following Unilateral Ureteral Obstruction

High serum levels of carbohydrate antigen19-9 (CA19-9) have been detected in patients with pancreatic cancer and described in several recent case reports of patients with hydronephrosis. However, the mechanism of high serum levels of CA19-9 among hydronephrosis cases remains to be elucidated. In this study, we established a mouse unilateral ureteral obstruction (UUO) model to investigate the expression of CA19-9 protein in renal tissue. To investigate the progression of hydronephrosis following UUO, MR urography and pathological analysis were performed. CA19-9 expression was examined by immunohistochemistry and western blot analysis. MR urography revealed that the grade of pelvic dilatation increased in a time dependent manner. Pathologically, both interstitial cellular infiltration and fibrosis were detected from the second to the fourteenth day after surgery in UUO mice. CA19-9 was detected in the UUO kidney after the second day. The immunoblot analysis revealed that the elevated expression of CA19-9 was demonstrated at an early stage of obstructive nephropathy. Our study shows that the ureteral obstructed kidney is dominated by cell infiltration and induced fibrosis. The selective expression of CA19-9 was detected in renal fibrous tissue. Based on these findings, the level of CA19-9 might be a good indicator for onset of renal fibrosis induced by obstruction

Immunohistochemical Analysis of Connexin43 Expression in Infertile Human Testes

Connexin43 (Cx43) is abundantly expressed in mammalian testes and implicated in the regulation of cell-to-cell interaction between germ cells and Sertoli cells, which is essential to the normal process of spermatogenesis. In the present study, we investigated the relation between Cx43 expression and the degree of spermatogenesis in infertile human testes. Immunohistochemical analysis of Cx43 was performed on testicular biopsies from 29 patients with azoospermia (n=23) and severe oligospermia (n=6), who gave informed consent to this experiment. The degree of testicular spermatogenesis was evaluated by Johnsen score. In the interstitium, immunostaining for Cx43 was localized to some focal parts of plasma membrane between neighboring Leydig cells. In seminiferous tubules with normal spermatogenesis, Cx43 expression was found between Sertoli cells and germ cells. However, Cx43 expression in maturation arrest was decreased and located mainly in the basal compartment of seminiferous tubules. Finally, there was a significant positive correlation between histological score of spermatogenesis and intensity of Cx43 (p=0.0294). These data suggest that the alteration of Cx43 expression may be involved in spermatogenic impairment, and that the communication between Sertoli cells and germ cells through Cx43 may be important for maturation of spermatogenesis

Efficacy and safety of systemic chemotherapy and intra-arterial chemotherapy with/without radiotherapy for bladder preservation or as neo-adjuvant therapy in patients with muscle-invasive bladder cancer: A single-centre study of 163 patients

Introduction Patients with muscle-invasive bladder cancer (MIBC) often undergo various preoperative treatments to improve survival; however, their efficacy and safety remain unclear. Materials and methods The anti-tumour effects and adverse events were evaluated in 163 MIBC patients who received systemic chemotherapy (SC, n = 34), intra-arterial chemotherapy (IAC, n = 50), or combined IAC and radiotherapy (IAC + R, n = 79). Results Pathological complete responses were observed in 17.6%, 22.0%, and 43.0% of patients in the SC, IAC, and IAC + R groups, respectively, with respective 5-year overall survival rates of 42.0%, 46.7%, and 50.3%. Multivariate analysis showed that successful IAC + R protocol administration was a significant predictor for survival (hazard ratio = 0.16, p = 0.028). The incidence of severe adverse events was higher in the IAC + R group (36.7%) than in the SC (9.8%) and IAC groups (16.0%). Conclusions IAC + R was useful for patients with MIBC. Successful completion and optimal patient selection were important for this treatment strategy

Small Cell Carcinoma of the Ureter with Malignant Lymphoma: Case Report and Literature Review

A 78-year-old man was referred to our hospital for gross hematuria. Ultrasonography and magnetic resonance urography revealed tumor in the right lower ureter. Computed tomography revealed right cervical lymph node swelling and pathological diagnosis was diffuse large B-cell lymphoma. Right nephroureterectomy was performed and pathologic examination revealed small cell carcinoma of the ureter with a small urothelial cell carcinoma component. As the patient had concomitant other malignancies, additional systemic chemotherapy was not performed. As of 3 months after operation, postoperative course has been uneventful. Only 11 cases of primary small cell carcinoma of the ureter have been described

Engineered biosynthesis of bacteriochlorophyll b in Rhodobacter sphaeroides.

Bacteriochlorophyll b has the most red-shifted absorbance maximum of all naturally occurring photopigments. It has a characteristic ethylidene group at the C8 position in place of the more common ethyl group, the product of a C8-vinyl reductase, which is carried by the majority of chlorophylls and bacteriochlorophylls used in photosynthesis. The subsequent and first step exclusive to bacteriochlorophyll biosynthesis, the reduction of the C7=C8 bond, is catalyzed by chlorophyllide oxidoreductase. It has been demonstrated that the enzyme from bacteriochlorophyll a-utilizing bacteria can catalyze the formation of compounds carrying an ethyl group at C8 from both ethyl- and vinyl-carrying substrates, indicating a surprising additional C8-vinyl reductase function, while the enzyme from organisms producing BChl b could only catalyze C7=C8 reduction with a vinyl substrate, but this product carried an ethylidene group at the C8 position. We have replaced the native chlorophyllide oxidoreductase-encoding genes of Rhodobacter sphaeroides with those from Blastochloris viridis, but the switch from bacteriochlorophyll a to b biosynthesis is only detected when the native conventional C8-vinyl reductase is absent. We propose a non-enzymatic mechanism for ethylidene group formation based on the absence of cellular C8-vinyl reductase activity

PufQ regulates porphyrin flux at the haem/bacteriochlorophyll branchpoint of tetrapyrrole biosynthesis via interactions with ferrochelatase

Facultative phototrophs such as Rhodobacter sphaeroides can switch between heterotrophic and photosynthetic growth. This transition is governed by oxygen tension and involves the large-scale production of bacteriochlorophyll, which shares a biosynthetic pathway with haem up to protoporphyrin IX. Here, the pathways diverge with the insertion of Fe(2+) or Mg(2+) into protoporphyrin by ferrochelatase or magnesium chelatase, respectively. Tight regulation of this branchpoint is essential, but the mechanisms for switching between respiratory and photosynthetic growth are poorly understood. We show that PufQ governs the haem/bacteriochlorophyll switch; pufQ is found within the oxygen-regulated pufQBALMX operon encoding the reaction centre-light harvesting photosystem complex. A pufQ deletion strain synthesises low levels of bacteriochlorophyll and accumulates the biosynthetic precursor coproporphyrinogen III; a suppressor mutant of this strain harbours a mutation in the hemH gene encoding ferrochelatase, substantially reducing ferrochelatase activity. FLAG-immunoprecipitation experiments retrieve a ferrochelatase-PufQ-carotenoid complex, proposed to regulate the haem/bacteriochlorophyll branchpoint by directing porphyrin flux towards bacteriochlorophyll production under oxygen-limiting conditions. The co-location of pufQ and the photosystem genes in the same operon ensures that switching of tetrapyrrole metabolism towards bacteriochlorophyll is coordinated with the production of reaction centre and light harvesting polypeptides. This article is protected by copyright. All rights reserved