Measurement of crude-cell-extract glycerol dehydratase activity in recombinant Escherichia coli using coupled-enzyme reactions

Journal of Industrial Microbiology & Biotechnology - Glycerol dehydratase (GDHt), which converts glycerol to 3-hydroxypropionaldehyde, is essential to the production of 1,3-propanediol...     

Type III DNA restriction and modification systems EcoP1 and EcoP15. Nucleotide sequence of the EcoP1 operon, the EcoP15 mod gene and some EcoP1 mod mutants

This paper presents the nucleotide sequence of the mod-res operon of phage P1, which encodes the two structural genes for the EcoP1 type III restriction and modification system. We have also sequenced the mod gene of the allelic EcoP15 system. The mod gene product is responsible for binding the system-specific DNA recognition sequences in both restriction and modification; it also catalyses the modification reaction. A comparison of the two mod gene product sequences shows that they have conserved amino and carboxyl ends but have completely different sequences in the middle of the molecules. Two alleles of the EcoP1 mod gene that are defective in modification but not in restriction were also sequenced. The mutations in both alleles lie within the non-conserved regions.     

Short-term antibody response after 1 dose of BNT162b2 vaccine in patients receiving hemodialysis

BACKGROUND:Patients receiving in-centre hemodialysis are at high risk of exposure to SARS-CoV-2 and death if infected. One dose of the BNT162b2 SARS-CoV-2 vaccine is efficacious in the general population, but responses in patients receiving hemodialysis are uncertain.METHODS:We obtained serial plasma from patients receiving hemodialysis and health care worker controls before and after vaccination with 1 dose of the BNT162b2 mRNA vaccine, as well as convalescent plasma from patients receiving hemodialysis who survived COVID-19. We measured anti–receptor binding domain (RBD) immunoglobulin G (IgG) levels and stratified groups by evidence of previous SARS-CoV-2 infection.RESULTS:Our study included 154 patients receiving hemodialysis (135 without and 19 with previous SARS-CoV-2 infection), 40 controls (20 without and 20 with previous SARS-CoV-2 infection) and convalescent plasma from 16 patients. Among those without previous SARS-CoV-2 infection, anti-RBD IgG was undetectable at 4 weeks in 75 of 131 (57%, 95% confidence interval [CI] 47% to 65%) patients receiving hemodialysis, compared with 1 of 20 (5%, 95% CI 1% to 23%) controls (p < 0.001). No patient with nondetectable levels at 4 weeks developed anti-RBD IgG by 8 weeks. Results were similar in non-immunosuppressed and younger individuals. Three patients receiving hemodialysis developed severe COVID-19 after vaccination. Among those with previous SARS-CoV-2 infection, median anti-RBD IgG levels at 8 weeks in patients receiving hemodialysis were similar to controls at 3 weeks (p = 0.3) and to convalescent plasma (p = 0.8).INTERPRETATION:A single dose of BNT162b2 vaccine failed to elicit a humoral immune response in most patients receiving hemodialysis without previous SARS-CoV-2 infection, even after prolonged observation. In those with previous SARS-CoV-2 infection, the antibody response was delayed. We advise that patients receiving hemodialysis be prioritized for a second BNT162b2 dose at the recommended 3-week interval.

Patients with end-stage kidney disease receiving incentre hemodialysis have been uniquely vulnerable during the COVID-19 pandemic. For these patients, unlike for most other people, self-isolation to avoid exposure to SARS-CoV-2 is impossible. Most patients receiving hemodialysis must leave their homes 3 times weekly to receive their life-saving treatments, often in shared spaces for hours at a time. COVID-19 case fatality rates are 20%–30% for patients receiving hemodialysis —10 times higher than in the general population.^1,2 Advanced age, multiple comorbidities and blunted immune response likely all contribute to the high COVID-19 death rates in this population. Some hemodialysis centres have thus prioritized these patients for vaccination.To facilitate wider vaccine distribution during current shortages, ³ the National Advisory Committee on Immunization of Canada has recommended delaying the second dose of the BNT162b2 vaccine from 3 to 16 weeks.⁴ In a randomized controlled trial (RCT), the clinical efficacy of the BNT162b2 was reported to be greater than 80% at 3 weeks after the first dose.⁵ However, no patients receiving hemodialysis were enrolled in this trial.⁵ Patients with end-stage kidney disease receiving hemodialysis often have impairments in both humoral and cellular immune responses⁶ and are noted to have lower antibody responses to other vaccines.⁷ Whether patients receiving hemodialysis develop robust immune responses after vaccination against SARS-CoV-2 remains uncertain.⁸ Data are required to better inform Canadian public health policy on whether second doses of vaccine can be safely delayed in this population.Usually, once clinical trials are completed, antibody levels can be used as surrogate measures of vaccine efficacy, such as with hepatitis B⁹ and influenza.¹⁰ With respect to the novel coronavirus SARS-CoV-2, although there is increasing understanding of the antibodies that best correlate with viral neutralization and T-cell responses,^11,12 assays vary from laboratory to laboratory and as yet there are no internationally accepted standards defining what antibody levels constitute immunity.¹³ The only way to evaluate vaccine efficacy using antibody levels, therefore, is through direct experimental comparison with controls who are known to reliably develop immunity after vaccination (i.e., healthy individuals similar to those enrolled in the RCT showing vaccine efficacy⁵) or who have developed immunity after natural infection (i.e., survivors of COVID-19).We sought to determine whether short-term antibody responses after a single dose of the BNT162b2 mRNA vaccine are comparable between patients receiving hemodialysis and healthy individuals, and how this compares with antibody responses in patients receiving hemodialysis who survived natural infection with SARS-CoV-2.     

Review on the Biological Mechanisms Associated with Depo-Provera and HIV-1 Risk Acquisition in Women

Women constitute more than 50% out of millions of individuals infected with HIV-1, the major causative agent of acquired immune deficiency syndrome. About 40% of HIV-1 infections have been reported to initiate in the female reproductive tract. However, the mechanisms through which these infections are spread are poorly understood; hence, there is now a major concern in women who use long acting injectable hormonal contraceptives, particularly Depo-Provera and an increase of HIV-1 risk acquisition. Based on literature, Depo-Provera has an affinity for both the glucocorticoid receptor and the progesterone receptor in the female reproductive tract. Therefore, investigating HIV-1 pathogenesis in the female reproductive tract via the glucocorticoid receptor and the progesterone receptor mechanisms in response to the effect of Depo-Provera is of great importance.     

UK legislation on analgesic packs: before and after study of long term effect on poisonings

Objective To evaluate the long term effect of legislation limiting the size of packs of analgesics sold over the counter.Design Before and after study.Setting Suicides in England and Wales, data from six liver units in England and Scotland and five general hospitals in England, and UK data on sales of analgesics, between September 1993 and September 2002.Data sources Office for National Statistics; six liver units in England and Scotland; monitoring systems in general hospitals in Oxford, Manchester, and Derby; and Intercontinental Medical Statistics Health UK.Main outcome measures Deaths by suicidal overdose with paracetamol, salicylates, or ibuprofen; numbers of patients admitted to liver units, listed for liver transplant, and undergoing transplantations for paracetamol induced hepatotoxicity; non-fatal self poisonings with analgesics and numbers of tablets taken; and sales figures for analgesics.Results Suicidal deaths from paracetamol and salicylates were reduced by 22% (95% confidence interval 11% to 32%) in the year after the change in legislation on 16 September 1998, and this reduction persisted in the next two years. Liver unit admissions and liver transplants for paracetamol induced hepatotoxicity were reduced by around 30% in the four years after the legislation. Numbers of paracetamol and salicylate tablets in non-fatal overdoses were reduced in the three years after the legislation. Large overdoses were reduced by 20% (9% to 29%) for paracetamol and by 39% (14% to 57%) for salicylates in the second and third years after the legislation. Ibuprofen overdoses increased after the legislation, but with little or no effect on deaths.Conclusion Legislation restricting pack sizes of analgesics in the United Kingdom has been beneficial. A further reduction in pack sizes could prevent more deaths.     

Semantically assessing the reliability of protein interactions

Protein–protein interactions (PPIs) play very important roles in many cellular processes, and provide rich information for discovering biological facts and knowledge. Although various experimental approaches have been developed to generate large amounts of PPI data for different organisms, high-throughput experimental data usually suffers from high error rates, and as a consequence, the biological knowledge discovered from this data is distorted or incorrect. Therefore, it is vital to assess the quality of protein interaction data and extract reliable protein interactions from the high-throughput experimental data. In this paper, we propose a new Semantic Reliability (SR) method to assess the reliability of each protein interaction and identify potential false-positive protein interactions in a dataset. For each pair of target interacting proteins, the SR method takes into account the semantic influence between proteins that interact with the target proteins, and the semantic influence between the target proteins themselves when assessing the interaction reliability. Evaluations on real protein interaction datasets demonstrated that our method outperformed other existing methods in terms of extracting more reliable interactions from original protein interaction datasets.     

Pyrazolopyrimidinone Based Selective Inhibitors of PDE5 for the Treatment of Erectile Dysfunction

Continuing research with our earlier finding of sildenafil based analogs in the search of new inhibitors of PDE5 for erectile dysfunction suggested that there is a scope of modifications at N-methylpiperazine ring with hydrophobic region followed by hydrogen bond donor or acceptor region. However, the leads identified earlier had some limitations like poor pharmacokinetic (PK) profile, low aqueous solubility and poor bioavailability. In this direction, a new series of sildenafil based analogs were designed, synthesized and screened for their PDE5 inhibitory activity. In this series compound 18 was found to have excellent in vitro activity with selectivity towards PDE5 isozyme, also the in vivo activity and pharmacokinetic profile was excellent. The cyp inhibition and CaCO₂ permeability was also excellent for compound 18 .