Vanillyl alcohol oxidase from Diplodia corticola:Residues Ala420 and Glu466 allow for efficient catalysis of syringyl derivatives

Vanillyl alcohol oxidases belong to the 4-phenol oxidases family and are found predominantly in lignin-degrading ascomycetes. Systematical investigation of the enzyme family at the sequence level resulted in discovery and characterization of the second recombinantly produced VAO member, DcVAO, from Diplodia corticola. Remarkably high activities for 2,6-substituted substrates like 4-allyl-2,6-dimethoxy-phenol (3.5 ± 0.02 U mg -1) or 4-(hydroxymethyl)-2,6-dimethoxyphenol (6.3 ± 0.5 U mg -1) were observed which could be attributed to a Phe to Ala exchange in the catalytic center. In order to rationalize this rare substrate preference among VAOs, we resurrected and characterized three ancestral enzymes and performed mutagenesis analyses. The results indicate that a Cys/Glu exchange was required to retain activity for ɣ-hydroxylations and shifted the acceptance towards benzyl ethers (up to 4.0 ± 0.1 U mg -1). Our findings contribute to the understanding of the functionality of VAO enzyme group, and with DcVAO, we add a new enzyme to the repertoire of ether cleaving biocatalysts. </p

PREDICT identifies precipitating events associated with the clinical course of acutely decompensated cirrhosis

Background & Aims: Acute decompensation (AD) of cirrhosis may present without acute-on-chronic liver failure (ACLF) (ADNo ACLF), or with ACLF (AD-ACLF), defined by organ failure(s). Herein, we aimed to analyze and characterize the precipitants leading to both of these AD phenotypes. Methods: The multicenter, prospective, observational PREDICT study (NCT03056612) included 1,273 non-electively hospitalized patients with AD (No ACLF = 1,071; ACLF = 202). Medical history, clinical data and laboratory data were collected at enrolment and during 90-day follow-up, with particular attention given to the following characteristics of precipitants: induction of organ dysfunction or failure, systemic inflammation, chronology, intensity, and relationship to outcome. Results: Among various clinical events, 4 distinct events were precipitants consistently related to AD: proven bacterial infections, severe alcoholic hepatitis, gastrointestinal bleeding with shock and toxic encephalopathy. Among patients with precipitants in the AD-No ACLF cohort and the AD-ACLF cohort (38% and 71%, respectively), almost all (96% and 97%, respectively) showed proven bacterial infection and severe alcoholic hepatitis, either alone or in combination with other events. Survival was similar in patients with proven bacterial infections or severe alcoholic hepatitis in both AD phenotypes. The number of precipitants was associated with significantly increased 90day mortality and was paralleled by increasing levels of surrogates for systemic inflammation. Importantly, adequate first-line antibiotic treatment of proven bacterial infections was associated with a lower ACLF development rate and lower 90-day mortality. Conclusions: This study identified precipitants that are significantly associated with a distinct clinical course and prognosis in patients with AD. Specific preventive and therapeutic strategies targeting these events may improve outcomes in patients with decompensated cirrhosis. Lay summary: Acute decompensation (AD) of cirrhosis is characterized by a rapid deterioration in patient health. Herein, we aimed to analyze the precipitating events that cause AD in patients with cirrhosis. Proven bacterial infections and severe alcoholic hepatitis, either alone or in combination, accounted for almost all (96-97%) cases of AD and acute-on-chronic liver failure. Whilst the type of precipitant was not associated with mortality, the number of precipitant(s) was. This study identified precipitants that are significantly associated with a distinct clinical course and prognosis of patients with AD. Specific preventive and therapeutic strategies targeting these events may improve patient outcomes. (c) 2020 European Association for the Study of the Liver. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Comparison of Blood Pressure and Kidney Markers between Adolescent Former Preterm Infants and Term Controls

Staub E, Urfer-Maurer N, Lemola S, et al. Comparison of Blood Pressure and Kidney Markers between Adolescent Former Preterm Infants and Term Controls. Children . 2020;7(9): 141.Background: Preterm infants are at an increased risk of developing hypertension and chronic kidney disease later in life. No recommendations exist for blood pressure (BP) and renal follow up for these patients. Aim: To compare BP and serum and urinary kidney markers between preterm-born adolescents and term-born controls. Methods: BP measurements in 51 preterm-born (<= 32 weeks gestational age) and 82 term-born adolescents at the age of 10-15 years were conducted. Stepwise regression analysis explored the association between BP and participant characteristics. Kidney markers measured in the serum and urine were creatinine, neutrophil gelatinase-associated lipocalin (NGAL), and uromodulin. Kidney markers measured in the serum were cystatin C, beta-2 microglobulin, and beta trace protein. Results: Systolic BP was significantly higher in preterm boys compared with term boys, but not in girls, and low birth weight was associated with higher BP in boys. In the preterm group, maternal hypertension/preeclampsia and adolescent height were associated with higher systolic BP. Serum creatinine and NGAL were significantly higher in the preterm group. Conclusions: Our study confirms an inverse sex-dependant relationship between birth weight and BP at adolescent age. The higher serum creatinine and NGAL in the preterm group may indicate that premature birth affects kidney function in the long term

Vanillyl alcohol oxidase from Diplodia corticola\textit {Diplodia corticola}

Vanillyl alcohol oxidases (VAOs) belong to the 4-phenol oxidases family and are found predominantly in lignin-degrading ascomycetes. Systematical investigation of the enzyme family at the sequence level resulted in discovery and characterization of the second recombinantly produced VAO member, $\it Dc$VAO, from $\textit {Diplodia corticola}$. Remarkably high activities for 2,6-substituted substrates like 4-allyl-2,6-dimethoxy-phenol (3.5 $\pm$ 0.02 U $mg^{−1}$) or 4-(hydroxymethyl)-2,6-dimethoxyphenol (6.3 $\pm$ 0.5 U $mg^{−1}$) were observed, which could be attributed to a Phe to Ala exchange in the catalytic center. In order to rationalize this rare substrate preference among VAOs, we resurrected and characterized three ancestral enzymes and performed mutagenesis analyses. The results indicate that a Cys/Glu exchange was required to retain activity for $\gamma$-hydroxylations and shifted the acceptance towards benzyl ethers (up to 4.0 $\pm$ 0.1 U $mg^{−1}$). Our findings contribute to the understanding of the functionality of VAO enzyme group, and with $\it Dc$VAO, we add a new enzyme to the repertoire of ether cleaving biocatalysts