• Benson Rahbek posted an update 6 months, 3 weeks ago

    Fermentative nitrogen-fixing bacteria have not yet been examined in detail in thermal environments. In the present study, we isolated the thermophilic fermentative bacterium, strain YA01 from a hot spring. This strain grew at temperatures up to 78°C. A phylogenetic analysis based on its 16S rRNA gene sequence indicated that strain YA01 belonged to the genus Caldicellulosiruptor, which are fermentative bacteria in the phylum Firmicutes, with 97.7-98.0% sequence identity to its closest relatives. Strain YA01 clearly exhibited N2-dependent growth at 70°C. We also confirmed N2-dependent growth in the relatives of strain YA01, Caldicellulosiruptor hydrothermalis 108 and Caldicellulosiruptor kronotskyensis 2002. The nitrogenase activities of these three strains were examined using the acetylene reduction assay. Similar activities were detected for all tested strains, and were slightly suppressed by the addition of ammonium. A genome analysis revealed that strain YA01, as well as other Caldicellulosiruptor, possessed a gene set for nitrogen fixation, but lacked the nifN gene, which encodes a nitrogenase iron-molybdenum cofactor biosynthesis protein that is commonly detected in nitrogen-fixing bacteria. The amino acid sequences of nitrogenase encoded by nifH, nifD, and nifK shared 92-98% similarity in Caldicellulosiruptor. A phylogenetic tree of concatenated NifHDK sequences showed that NifHDK of Caldicellulosiruptor was in the deepest clade. To the best of our knowledge, this is the first study to demonstrate the nitrogen-fixing ability of fermentative bacteria at 70°C. Caldicellulosiruptor may have retained an ancient nitrogen-fixing enzyme system.Phytophthora species cause destructive plant diseases worldwide. All Phytophthora species, except for one, are listed as plant quarantine organisms in Japan. The exception, Phytophthora nicotianae is considered to be a domestic species. The injurious pests Phytophthora ramorum, Phytophthora lateralis, and Phytophthora kernoviae are invasive pathogens that cause tree mortality worldwide, mainly in the United States and the United Kingdom. To effectively control Phytophthora diseases, we established detection methods that utilize the loop-mediated isothermal amplification (LAMP) of the genus Phytophthora and the four species P. ramorum, P. lateralis, P. kernoviae, and P. nicotianae. LAMP primers for P. ramorum, P. lateralis, and P. kernoviae were newly designed in the present study. Our multiplex assay includes the detection of plant DNA as an internal control. When the optimum ratio between plant and pathogen primers was used in multiplex LAMP assays, 1 pg to 100 fg of pathogen DNA was detected with similar sensitivity to that in simplex LAMP assays. The detection of plant DNA in the absence of pathogens enables us to check for and avoid undesirable negative results caused by enzyme inactivation or the contamination of amplification inhibitors from plant tissues. The total time from sample collection to results is approximately 120 min, and, thus, our multiplex LAMP assay may be used as an accurate and time-saving detection method for Phytophthora pathogens.A 60-year-old man was admitted for investigation of a mediastinal cystic lesion. During endoscopic retrograde pancreatography, the contrast medium leaked from the head of the main pancreatic duct, and the cystic fluid collected with endoscopic ultrasonography (EUS) -guided aspiration showed high levels of pancreatic enzymes. Therefore, we diagnosed mediastinal pancreatic pseudocyst. The pseudocyst shrank as a result of EUS-guided drainage, and an endoscopic nasopancreatic drainage tube was then placed to close the fistula of the pancreatic duct. check details This case suggests that endoscopic procedures could be useful for the diagnosis and treatment of mediastinal pancreatic pseudocyst. We review 48 case reports of mediastinal pancreatic pseudocyst and discuss the usefulness of endoscopic procedures for diagnosis and treatment.A 76-year-old woman with a history of radiation therapy for vaginal cancer was referred to our hospital because of fever and hepatobiliary dysfunction. Computed tomography showed stenosis of the lower bile duct and edema-like changes in the duodenum from the descending to transverse parts. Endoscopic biliary stenting was performed according to the rendezvous method. Squamous cell carcinoma, similar to vaginal cancer, was found on pathological examination of the duodenum. We accordingly diagnosed obstructive jaundice and duodenal stenosis caused by vaginal cancer and retroperitoneal metastasis. To the best of our knowledge, other such cases have not been reported.Contrast medium-enhanced computed tomography revealed a mass in the liver of a 65-year-old man. The edge but not the center of the mass was enhanced. Ultrasonography-guided percutaneous needle biopsy revealed the diagnosis of angiosarcoma of the liver, and it was treated with chemotherapy. Angiosarcoma of the liver has various appearances on imaging and is not often diagnosed while patients are alive. If the tumor is difficult to diagnose by imaging and thought to be unresectable, a biopsy can help in guiding treatment, but treatment should be adapted with caution.A 52-year-old woman had a surgical history of breast cancer. A follow-up blood test showed that the level of carcinoembryonic antigen was elevated. Esophagogastroduodenoscopy revealed a Borrmann type IV tumor in the stomach, and biopsy revealed poorly differentiated adenocarcinoma with signet ring cells. The preoperative diagnosis was gastric cancer, and gastrectomy was attempted, but the procedure was changed to laparotomy because of the peritoneal dissemination of cancer. Chemotherapy for gastric cancer after laparotomy enabled the patient to maintain stable disease without progression for a long period. Thirteen years later, poorly differentiated adenocarcinoma of the stomach, which had not been detected for 10 years despite routine examination every year, was identified by endoscopic biopsy. Immunohistochemistry studies showed strong positivity of both estrogen and progesterone receptors of adenocarcinoma. We reviewed all the past pathological specimens and finally corrected the diagnosis as a gastric metastasis of breast cancer.

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