Identification and characterization of a novel α-haemolytic streptococci, Streptococcus parapneumoniae sp. nov., which caused bacteremia with pyelonephritis.

OBJECTIVES: We report a case of bacteremia with pyelonephritis in an adult male with an underlying disease caused by α-hemolytic streptococci. α-Hemolytic streptococci were isolated from blood, but it was challenging to identify its species. This study aimed to characterize the causative bacterium SP4011 and to elucidate its species. METHODS: The whole-genome sequence and biochemical characteristics of SP4011 were determined. Based on the genome sequence, phylogenetic analysis was performed with standard strains of each species of α-hemolytic streptococci. Digital DNA-DNA hybridization (dDDH) and average nucleotide identity (ANI) values were calculated. RESULTS: SP4011 showed optochin susceptibility and bile solubility, but did not react with pneumococcal omni antiserum. Phylogenetic analysis of the whole-genome sequence showed that SP4011 clustered with S. pneumoniae and S. pseodopneumoniae and was most closely related to S. pseodopneumoniae. Genomic analysis revealed that ANI and dDDH values between SP4011 and S. pseodopneumoniae were 94.0 % and 56.0 %, respectively, and between SP4011 and S. pneumoniae were 93.3 % and 52.2 %, respectively. Biochemical characteristics also showed differences between SP4011 and S. pseodopneumoniae and between SP4011 and S. pneumoniae. These results indicate that SP4011 is a novel species. CONCLUSION: Our findings indicate that SP4011 is a novel species of the genus Streptococcus. SP4011 has biochemical characteristics similar to S. pneumoniae, making it challenging to differentiate and requiring careful clinical diagnosis. This isolate was proposed to be a novel species, Streptococcus parapneumoniae sp. nov. The strain type is SP4011T (= JCM 36068T = KCTC 21228T).

Urinary liver-type fatty acid-binding protein level as a prognostic indicator of acute kidney injury secondary to severe falciparum malaria.

Acute kidney injury (AKI) secondary to severe falciparum malaria possesses a high mortality rate; however, a prognostic marker of renal dysfunction has not yet been identified. Thus, we reported a case of a patient with AKI secondary to falciparum malaria who underwent hemodialysis and a renal biopsy due to prolonged renal dysfunction. The male patient, in his 50 s, presented to our hospital with vomiting, diarrhea, fever, and decreased level of consciousness. The Giemsa-stained peripheral blood film revealed approximately 5% parasitemia, and a rapid diagnostic test was positive for Plasmodium falciparum. He was diagnosed with severe falciparum malaria and was started on quinine hydrochloride. Hemodialysis was initiated due to the decreased urine output and fluid retention. Subsequently, he was weaned off hemodialysis. The histopathological analysis of a renal biopsy revealed interstitial fibrosis, tubular atrophy, and chronic inflammatory cell infiltration; thus, malarial nephropathy was diagnosed. Thereafter, his renal function stabilized, and he was discharged from the hospital. The urinary liver-type fatty acid-binding protein (L-FABP) level decreased before renal function improved. Our report highlighted that long-term follow-up is essential for severe AKI secondary to malaria. The urinary L-FABP level may be a useful prognostic indicator of AKI secondary to severe falciparum malaria.

A retrospective study describing the effective exchange of total blood plasma for disease control in the exacerbation of serpiginous choroiditis.

INTRODUCTION: Serpiginous choroiditis presents with large yellow-white exudative lesions that occur near the optic nerve papillae, that progresses slowly with repeated relapses and cures. Although infection and autoimmunity have been implicated, the cause is unknown. METHODS: A man was diagnosed with serpiginous choroiditis on clinical and other examinations. He started treatment with oral corticosteroids, cyclophosphamide, adalimumab, azathioprine, rituximab, and mycophenolate mofetil. Only the steroids and cyclophosphamide had a therapeutic effect. Plasma exchange was initiated, and the lesions quickly resolved. RESULTS: Disease control has been maintained by plasma exchange and cyclophosphamide during flare-ups in the fall and winter, suggesting that plasma exchange is effective in the treatment of serpiginous choroiditis. CONCLUSION: The reproducible response with each recurrence suggests a strong association between the disease and autoimmunity. Furthermore, that some, as yet unknown, autoantibodies are involved in the pathogenesis of serpiginous choroiditis.

A Case of Glomerular Microangiopathy-like Nephropathy Caused by Hyperthyroidism.

A 49-year-old Japanese woman was admitted to our hospital with weight loss of 15 kg, nephrotic-range proteinuria (4.5 g/g.Cre), and hematuria over a 6-month period. She had received two doses of the COVID-19 vaccine one year before the onset of the disease, after which the estimated glomerular filtration rate increased. Laboratory tests and other tests led to a diagnosis of hyperthyroidism, and a kidney biopsy showed thrombotic microangiopathy-like glomerular microangiopathy comprising mainly glomerular endothelial cell damage. Thiamazole (30 mg) was started for the hyperthyroidism. Three months later, the thyroid function normalized, and two months later, the proteinuria and hematuria disappeared, suggesting that COVID-19 vaccination and these events were related.

Lewis Acid-Conjugated Pyrene Photoredox Catalyst Promoting the Addition Reaction of α-Silyl Amines with Benzalmalononitriles.

We developed the addition reaction of α-silyl amines with benzalmalononitriles catalyzed by a Mg2+-conjugated pyrene catalyst under visible light irradiation. The catalytic activity of this complex was higher than pyrene alone, a Mg2+ Lewis acid alone, and the sum of these two independent catalytic elements. The observed enhancement in catalytic activity was likely due to electrostatic interactions of the Mg2+ Lewis acid with the pyrene radical anion, which was generated through photoinduced single electron transfer from α-silyl amines to the catalyst's pyrene moiety.

Similar frequency and signature of untargeted substitutions induced by abasic site analog under reduced human APE1 conditions.

Abasic sites are formed in cells by various factors including environmental mutagens and considered to be involved in cancer initiation, promotion, and progression. A chemically stable abasic site analog (tetrahydrofuran-type analog, THF) induces untargeted base substitutions as well as targeted substitution and large deletion mutations in human cells. The untargeted substitutions may be initiated by the cleavage of the DNA strand bearing THF by the human apurinic/apyrimidinic endonuclease 1 (APE1) protein, the major repair enzyme for THF and abasic sites. To examine the effects of lower APE1 levels, the protein was knocked down by siRNA in human U2OS cells. A plasmid containing a single THF modification outside the supF gene was introduced into the knockdown cells, and the untargeted substitution mutations in the reporter gene were analyzed. Unexpectedly, the knockdown had no evident impact on their frequency and spectrum. The G bases of 5'-GpA-3' dinucleotides on the modified strand were quite frequently substituted, with and without the APE1 knockdown. These results suggested that the DNA strand cleavage by APE1 is not essential for the THF-induced untargeted base substitutions.

Chromium-Catalyzed Linear-Selective Alkylation of Aldehydes with Alkenes.

We developed a chromium-catalyzed, photochemical, and linear-selective alkylation of aldehydes with alkylzirconium species generated in situ from a wide range of alkenes and Schwartz's reagent. Photochemical homolysis of the C-Zr bond afforded alkyl radicals, which were then trapped by a chromium complex catalyst to generate the alkylchromium(III) species for polar addition to aldehydes. The reaction proceeded with high functional group tolerance at ambient temperature under visible-light irradiation.

Large deletions and untargeted substitutions induced by abasic site analog on leading versus lagging strand templates in human cells.

The tetrahydrofuran-type abasic site analog (THF) induces large deletion mutations in human cells. To compare the large deletions induced by THF on leading and lagging strand templates, plasmid DNAs bearing the analog at a specific position outside the supF gene were introduced into human U2OS cells. The replicated DNAs recovered from the transfected cells were electroporated into an Escherichia coli indicator strain. THF on the lagging strand template produced more supF mutants than THF on the leading strand template. This unequal mutagenicity was due to the higher frequencies of not only large deletions but also untargeted base substitutions induced in the gene. These results suggested that both types of mutations occur more frequently when abasic sites are formed on the lagging strand template.

Analysis of large deletion mutations induced by abasic site analog in human cells.

BACKGROUND: Abasic sites are formed spontaneously and by nucleobase chemical modifications and base excision repair. A chemically stable abasic site analog was site-specifically introduced into replicable plasmid DNAs, which were transfected into human U2OS cells. The amplified DNAs were recovered from the cells and used for the transformation of a bacterial indicator strain. RESULTS: Large deletion mutations were induced by the analog, in addition to point mutations at the modified site. No apparent sequence homology at the deletion junctions was found. CONCLUSION: These results suggested that the large deletions induced by the abasic site analog are formed by homology-independent events.

Anti-hepatitis C Virus Natural Product from a Fungus, Penicillium herquei.

New diazabicyclo[2.2.2]octane derivatives, peniciherquamides A-C (1-3), and a novel herqueinone derivative, neoherqueinone (5), were isolated from a fungal culture broth of Penicillium herquei. The structures of these novel compounds were determined by interpretation of spectroscopic data (1D/2D NMR, MS, and IR). Four known compounds, preparaherquamide (4), peniciherqueinone (6), and herqueinone/isoherqueinone (7/7a), were also obtained. The isolated compounds were tested for anti-hepatitis C virus (HCV) activity, and peniciherquamide C (3) was found to display an IC50 value of 5.1 µM. To our knowledge, this is the first report of a diazabicyclo[2.2.2]octane derivative with anti-HCV activity.

Total synthesis of (+)-Sch 725680: inhibitor of mammalian A-, B-, and Y-family DNA polymerases.

The total synthesis of (+)-Sch 725680, a member of the hydrogenated azaphilone family, has been accomplished. The synthesis confirmed the absolute configuration and biological activities of the natural product. A key reaction to construct a hydrogenated azaphilone core skeleton is a Ti-mediated aldol reaction.

I(2020)T leucine-rich repeat kinase 2, the causative mutant molecule of familial Parkinson's disease, has a higher intracellular degradation rate than the wild-type molecule.

Leucine-rich repeat kinase 2 (LRRK2) has been identified as the causal gene for autosomal dominant familial Parkinson's disease (PD), although the mechanism of neurodegeneration involving the mutant LRRK2 molecules remains unknown. In the present study, we found that the protein level of transfected I(2020)T mutant LRRK2 was significantly lower than that of wild-type and G(2019)S mutant LRRK2, although the intracellular localization of the I(2020)T and wild-type molecules did not differ. Pulse-chase experiments proved that the I(2020)T LRRK2 molecule has a higher degradation rate than wild-type or G(2019)S LRRK2. Upon addition of proteasome and lysosome inhibitors, the protein level of I(2020)T mutant LRRK2 reached that of the wild-type. These results indicate that I(2020)T mutant LRRK2 is more susceptible to post-translational degradation than the wild-type molecule. Our results indicate a novel molecular feature characteristic to I(2020)T LRRK2, and provide a new insight into the mechanism of neurodegeneration caused by LRRK2.

Accumulation of oxidative stress around the stroke-like lesions of MELAS patients.

To investigate the relationship between oxidative stress and progressive spread of the stroke-like lesions in mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) with 3243A>G mutation, we retrospectively analyzed the spread frequency in patients with and without treatment with the radical scavenger edaravone. Oxidative damage and defensive enzymes were histologically evaluated. Spread was significantly less frequent in the patients treated with edaravone. Although 8-hydroxy-2'-deoxyguanosine, a marker for oxidative damage of DNA, was obviously accumulated in peri-lesional surviving neurons, manganese superoxide dismutase and 8-oxoguanine glycosylase 1 were not up-regulated in those neurons. Increased oxidative stress and insufficient defense could be involved in the pathogenesis of the spreading lesions in MELAS.

Diagnosis of cerebral cortical vein thrombosis with T2* weighted magnetic resonance imaging.

A 47-year-old woman presented with paresthesia in her left arm and trunk. She was diagnosed as having an arterial pure sensory stroke at first presentation. On the second hospital day, left hemiparesis developed after convulsions. Magnetic resonance (MR) imaging revealed a hyperintense lesion involving the right parietal lobe on diffusion weighted image. The T2* weighted image disclosed a linear hypointense lesion in the same area. Progressive feature of her symptoms and T2* weighted MR image prompted us to perform MR venography. MR venography confirmed the diagnosis of cortical vein and sagittal sinus thrombosis. Her symptoms attenuated gradually after anticoagulation therapy. Gene analysis showed type I anti-thrombin III (ATIII) deficiency due to the novel mutation of AT III gene. T2* weighted imaging may be much more sensitive than other imaging to detect thrombosed cortical vein during the first week after onset. Rapid diagnosis induced appropriate treatment and monitoring of the patient.