Crystalline 2-Ketogluconate Reductase from Acetobacter ascendens,the Second Instance of Crystalline Enzyme in Genus Acetobacter

Crystalline 2-ketogluconate reductase in genus Acetobacter was prepared from cell free extract of Acetobacter ascendens. Crystalline enzyme was purified 13,000-fold with a yield of 15%. Affinity chromatography on blue-dextran Sepharose 4B column successfully purified the enzyme. The enzyme was composed of three identical subunits with a molecular weight of 40,000. Substrate specificity of 2-ketogluconate reductase from two genera of acetic acid bacteria was compared using highly purified enzyme preparations, and it was confirmed that gluconate oxidation activity of the enzyme was intrinsically weak or absent in genus Acetobacter and intense in Gluconobacter. This fact must be a useful criterion for classification of acetic acid bacteria.     

Ng-Methylated Arginines in Broad Bean Seed

l-N^g-Methylarginine, l-N^g,N^g-dimethylarginine and ethanolamine were isolated from basic amino acids fraction of broad bean (Vicia faba L.) seed. The presence of N^g,N′^g-dimethylarginine was also suggested.     

Distribution and Solubilization of Particulate Gluconate Dehydrogenase and Particulate 2-Ketogluconate Dehydrogenase in Acetic Acid Bacteria

The distribution of two particulate enzymes, gluconate dehydrogenase (GDH) and 2-ketogluconate dehydrogenase (2KGDH), was investigated with cell free extract through 26 strains of genus Acetobacter and genus Gluconobacter. GDH activity was found in the cell free extracts from all strains of genus Gluconobacter and two species of genus Acetobacter, A. aceti and A. aurantium. High activity of 2KGDH was also found in the pigment-producing strains of genus Gluconobacter.

Best solubilization of particulate enzymes was attained with the highest recovery when 10 mg of Triton X–100 and 30 mg of protein of particulate fractions in 1 ml of 0.01 m phosphate buffer, pH 6.0, are incubated for 9 hr at 5°C with continuous stirring.

By comparison of the total enzyme activity of particulate enzymes with that of NAD(P)-linked enzymes in the cell free extract, it was obvious that the formation of ketogluconates by particulate enzymes was much more predominant, roughly over 100 times higher, as that of NAD(P)-linked enzymes.     

Caffeine fostering of mycoparasitic fungi against phytopathogens

Caffeine (1,3,7-trimethixanthine) is a typical purine alkaloid produced in more than 80 plant species. Its biological role is considered to strengthen plant''s defense capabilities, directly as a toxicant to biotic attackers (allelopathy) and indirectly as an activator of defense system (priming). Caffeine is actively secreted into rhizosphere through primary root, and possibly affects the structure of microbe community nearby. The fungal community in coffee plant rhizosphere is enriched with particular species, including Trichoderma family, a mycoparasite that attacks and kills phytopathogens by coiling and destroying their hyphae. In the present study, the caffeine response of 8 filamentous fungi, 4 mycoparasitic Trichoderma, and 4 prey phytopathogens, was examined. Results showed that allelopathic effect of caffeine on fungal growth and development was differential, being stronger on pathogens than on Trichoderma species. Upon confronting, the prey immediately ceased the growth, whereas the predator continued to grow, indicating active mycoparasitism to have occurred. Caffeine enhanced mycoparasitism up to 1.7-fold. Caffeine thus functions in a double-track manner against fungal pathogens: first by direct suppression of growth and development, and second by assisting their natural enemy. These observations suggest that caffeine is a powerful weapon in the arms race between plants and pathogens by fostering enemy''s enemy, and we propose the idea of "caffeine fostering" as the third role of caffeine.     

Application of the backstepping method to the prediction of increase or decrease of infected population

Background

In mathematical epidemiology, age-structured epidemic models have usually been formulated as the boundary-value problems of the partial differential equations. On the other hand, in engineering, the backstepping method has recently been developed and widely studied by many authors.

Methods

Using the backstepping method, we obtained a boundary feedback control which plays the role of the threshold criteria for the prediction of increase or decrease of newly infected population. Under an assumption that the period of infectiousness is same for all infected individuals (that is, the recovery rate is given by the Dirac delta function multiplied by a sufficiently large positive constant), the prediction method is simplified to the comparison of the numbers of reported cases at the current and previous time steps.

Results

Our prediction method was applied to the reported cases per sentinel of influenza in Japan from 2006 to 2015 and its accuracy was 0.81 (404 correct predictions to the total 500 predictions). It was higher than that of the ARIMA models with different orders of the autoregressive part, differencing and moving-average process. In addition, a proposed method for the estimation of the number of reported cases, which is consistent with our prediction method, was better than that of the best-fitted ARIMA model ARIMA(1,1,0) in the sense of mean square error.

Conclusions

Our prediction method based on the backstepping method can be simplified to the comparison of the numbers of reported cases of the current and previous time steps. In spite of its simplicity, it can provide a good prediction for the spread of influenza in Japan.

     

Age at Transition from Pediatric to Adult Care Has No Relationship with Mortality for Childhood-Onset Type 1 Diabetes in Japan: Diabetes Epidemiology Research International (DERI) Mortality Study

Objective

To follow up Japanese patients with type 1 diabetes for a maximum of 40 years to examine when they transitioned from pediatric care to adult care and to explore whether the attending physician, i.e., pediatrician or internist, was associated with prognosis.

Methods

Participants consisted of 1,299 patients who had been diagnosed as having type 1 diabetes at less than 15 years old between 1965 and 1979 identified through two nationwide surveys. Patients were classified as having received either pediatric care or adult care at the age of 15 and 30, and were compared for differences in mortality associated with the attending physician.

Results

The attending physicians were confirmed for a total of 1,093 patients at the age of 15. Of these patients, 43.8% and 40.3% received pediatric care and adult care, respectively. Of the 569 patients receiving pediatric care, 74.2%, 56.6%, 53.4%, and 51.3% continued with pediatric care at 20, 30, 40, and 50 years old, respectively. The attending physicians (pediatrician or internist) at the age of 15 and 30 had no significant impact on their survival (P = 0. 892, 0.411, respectively).

Conclusions

More than half of the patients who had received pediatric care at the age of 15 continued to receive pediatric care even after the age of 30, suggesting that their transition was far from smooth, while the attending physician at the age of both 15 and 30 was not a prognostic factor for mortality. Thus, the timing for transition to adult care in these patients has no relationship with mortality in Japan.     

Characterization of RyDEN (C19orf66) as an Interferon-Stimulated Cellular Inhibitor against Dengue Virus Replication

Dengue virus (DENV) is one of the most important arthropod-borne pathogens that cause life-threatening diseases in humans. However, no vaccine or specific antiviral is available for dengue. As seen in other RNA viruses, the innate immune system plays a key role in controlling DENV infection and disease outcome. Although the interferon (IFN) response, which is central to host protective immunity, has been reported to limit DENV replication, the molecular details of how DENV infection is modulated by IFN treatment are elusive. In this study, by employing a gain-of-function screen using a type I IFN-treated cell-derived cDNA library, we identified a previously uncharacterized gene, C19orf66, as an IFN-stimulated gene (ISG) that inhibits DENV replication, which we named Repressor of yield of DENV (RyDEN). Overexpression and gene knockdown experiments revealed that expression of RyDEN confers resistance to all serotypes of DENV in human cells. RyDEN expression also limited the replication of hepatitis C virus, Kunjin virus, Chikungunya virus, herpes simplex virus type 1, and human adenovirus. Importantly, RyDEN was considered to be a crucial effector molecule in the IFN-mediated anti-DENV response. When affinity purification-mass spectrometry analysis was performed, RyDEN was revealed to form a complex with cellular mRNA-binding proteins, poly(A)-binding protein cytoplasmic 1 (PABPC1), and La motif-related protein 1 (LARP1). Interestingly, PABPC1 and LARP1 were found to be positive modulators of DENV replication. Since RyDEN influenced intracellular events on DENV replication and, suppression of protein synthesis from DENV-based reporter construct RNA was also observed in RyDEN-expressing cells, our data suggest that RyDEN is likely to interfere with the translation of DENV via interaction with viral RNA and cellular mRNA-binding proteins, resulting in the inhibition of virus replication in infected cells.     

(Pro)renin receptor accelerates development of sarcopenia via activation of Wnt/YAP signaling axis

To extend life expectancy and ensure healthy aging, it is crucial to prevent and minimize age‐induced skeletal muscle atrophy, also known as sarcopenia. However, the disease's molecular mechanism remains unclear. The age‐related Wnt/β‐catenin signaling pathway has been recently shown to be activated by the (pro)renin receptor ((P)RR). We report here that (P)RR expression was increased in the atrophied skeletal muscles of aged mice and humans. Therefore, we developed a gain‐of‐function model of age‐related sarcopenia via transgenic expression of (P)RR under control of the CAG promoter. Consistent with our hypothesis, (P)RR‐Tg mice died early and exhibited muscle atrophy with histological features of sarcopenia. Moreover, Wnt/β‐catenin signaling was activated and the regenerative capacity of muscle progenitor cells after cardiotoxin injury was impaired due to cell fusion failure in (P)RR‐Tg mice. In vitro forced expression of (P)RR protein in C2C12 myoblast cells suppressed myotube formation by activating Wnt/β‐catenin signaling. Administration of Dickkopf‐related protein 1, an inhibitor of Wnt/β‐catenin signaling, and anti‐(P)RR neutralizing antibody, which inhibits binding of (P)RR to the Wnt receptor, significantly improved sarcopenia in (P)RR‐Tg mice. Furthermore, the use of anti‐(P)RR neutralizing antibodies significantly improved the regenerative ability of skeletal muscle in aged mice. Finally, we show that Yes‐associated protein (YAP) signaling, which is coordinately regulated by Wnt/β‐catenin, contributed to the development of (P)RR‐induced sarcopenia. The present study demonstrates the use of (P)RR‐Tg mice as a novel sarcopenia model, and shows that (P)RR‐Wnt‐YAP signaling plays a pivotal role in the pathogenesis of this disease.