2019-07-29·Angewandte Chemie, International Edition1区 · 化学
The Hydrogenobyric Acid Structure Reveals the Corrin Ligand as an Entatic State Module Empowering B12 Cofactors for Catalysis
1区 · 化学
作者: Kieninger, Christoph ; Deery, Evelyne ; Lawrence, Andrew D. ; Podewitz, Maren ; Wurst, Klaus ; Nemoto-Smith, Emi ; Widner, Florian J. ; Baker, Joseph A. ; Jockusch, Steffen ; Kreutz, Christoph R. ; Liedl, Klaus R. ; Gruber, Karl ; Warren, Martin J. ; Kraeutler, Bernhard
The B12 cofactors instill a natural curiosity regarding the primordial selection and evolution of their corrin ligand. Surprisingly, this important natural macrocycle has evaded molecular scrutiny, and its specific role in predisposing the incarcerated cobalt ion for organometallic catalysis has remained obscure. Herein, we report the biosynthesis of the cobalt-free B12 corrin moiety, hydrogenobyric acid (Hby), a compound crafted through pathway redesign. Detailed insights from single-crystal X-ray and solution structures of Hby have revealed a distorted helical cavity, redefining the pattern for binding cobalt ions. Consequently, the corrin ligand coordinates cobalt ions in desymmetrized "entatic" states, thereby promoting the activation of B12 -cofactors for their challenging chemical transitions. The availability of Hby also provides a route to the synthesis of transition metal analogues of B12 .
2013-09-01·Poultry Science2区 · 农林科学
Comparison of breast muscle traits and meat quality charactetistics in 2 commercial chicken hybrids
2区 · 农林科学
作者: Petracci, M. ; Sirri, F. ; Mazzoni, M. ; Meluzzi, A.
A trial was conducted to compare muscle traits and meat quality characteristics of the pectoralis muscle in 2 chicken commercial hybrids having standard (SBY) and high breast yield (HBY), respectively. A total of 2,124 one-day-old male chicks, equally divided into 2 experimental groups represented by strains (SBY and HBY), were grown using homogenous conditions and fed the same standard diets until reaching live weight of 4.2 kg at 53 and 55 d for the SBY and HBY groups, respectively. Thirty-six birds per each genotype were randomly selected, and their pectoralis major muscles were used to assess meat quality properties (color attributes, pH, drip loss, cook loss, Allo-Kramer shear values after cooking, moisture, proteins, total lipids, and ashes) as well as histological traits (cross-sectional area, frequency of abnormal fibers, and intramuscular fat infiltration). As expected, HBY genotype had higher breast yield (31.0 vs. 30.0%; P ≤ 0.05). Histological evaluations showed that HBY pectoralis muscles had higher cross-sectional fiber area coupled with a dramatically higher (P ≤ 0.001) incidence of abnormal fibers and more abundant infiltration of intramuscular fat. Moreover, histopathological anomalous features such as central nuclei, proliferation of endomysial and perimysial collagen, inflammatory infiltrate, and necrosis of the fibers were also observed. As for meat quality, SBY hybrid showed lower ultimate pH values (5.97 vs. 6.07; P ≤ 0.01), whereas overall color parameters were not affected by genotype. Breast meat from the HBY genotype also exhibited significantly lower ability to retain liquid during refrigerated storage (drip loss, 2.46 vs. 2.06%; P ≤ 0.05) and cooking (26.2 vs. 21.1%; P ≤ 0.05) as well as higher shear-force values (2.59 vs. 2.11 kg/g; P ≤ 0.001). Finally, with regard to chemical composition, significant differences (P ≤ 0.05) were detected in protein (22.8 vs. 23.5%) and lipid (1.65 vs. 1.82%) contents, which were significantly lower in the HBY hybrid, whereas moisture content tended (P = 0.07) to be inferior in the SBY hybrid.
2010-01-01·Hepatitis monthly4区 · 医学
Induced HBs antigenemia in healthy adults after immunization with two different hepatitis B recombinant vaccines.
4区 · 医学
作者: Masoud Ziaee ; Alireza Saádatjoo ; Malihe Mohamadpour ; Mohammad Hasan Namaei
BACKGROUND AND AIMS:
Currently, vaccination is the most effective protective tool against hepatitis B virus infection. Some studies have shown that positive results for a hepatitis B virus surface antigen (HBsAg) test may be seen after vaccination.
MATERIALS AND METHODS:
In this clinical trial study, 62 healthy adult volunteers were randomly assigned to receive either the Engerix-B or the Hepavax-Gene hepatitis B recombinant vaccine. Blood samples were drawn 1, 3, and 5 days after vaccination and were tested for HBsAg using two different ELISA kits (Behring and Mega).
HBsAg was positive in 5, 3, and 2 participants of the Engerix-B group in the 1st, 3rd, and 5th days after vaccination, respectively, using the Behring ELISA kit the test was positive in only one subject in the Hepavax-Gene group, on the 5th day after vaccination. No positive result was seen in any groups when the Mega ELISA kit was used to test the specimens.
Our results showed transient HBsAg antigenemia after vaccination against hepatitis B. This condition depends on the type of vaccine and the HBsAg diagnostic test.