Molecular analysis of the clavulanic acid regulatory gene isolated from an Iranian strain of Streptomyces clavuligerus, PTCC 1709

Objective: The clavulanic acid regulatory gene (claR) is in the clavulanic acid biosynthetic gene cluster that encodes ClaR. This protein is a putative regulator of the late steps of clavulanic acid biosynthesis. The aim of this research is the molecular cloning of claR, isolated from the Iranian strain of Streptomyces clavuligerus (S. clavuligerus). Materials and Methods: In this experimental study, two different strains of S. clavuligerus were used (PTCC 1705 and DSM 738), of which there is no claR sequence record for strain PTCC 1705 in all three main gene banks. The specific designed primers were subjected to a few base modifications for introduction of the recognition sites of BamHI and ClaI. The claR gene was amplified by polymerase chain reaction (PCR) using DNA isolated from S. clavuligerus PTCC 1705. Nested-PCR, restriction fragment length polymorphism (PCR-RFLP), and sequencing were used for molecular analysis of the claR gene. The confirmed claR was subjected to double digestion with BamHI and ClaI. The cut claR was ligated into a pBluescript (pBs) vector and transformed into E. coli. Results: The entire sequence of the isolated claR (Iranian strain) was identified. The presence of the recombinant vector in the transformed colonies was confirmed by the colony-PCR procedure. The correct structure of the recombinant vector, isolated from the transformed E. coli, was confirmed using gel electrophoresis, PCR, and double digestion with restriction enzymes. Conclusion: The constructed recombinant cassette, named pZSclaR, can be regarded as an appropriate tool for site directed mutagenesis and sub-cloning. At this time, claR has been cloned accompanied with its precisely selected promoter so it could be used in expression vectors. Hence the ClaR is known as a putative regulatory protein. The overproduced protein could also be used for other related investigations, such as a mobility shift assa

An Investigation into the Views about the Identity of God's Viceroy and the Succeeded One in the Phrase "I am about to place a viceroy in the Earth"

The phrase "I am about to place a viceroy in the earth" as a part of  the verse 30 in Surah Baqarah (The Cow) is regarded one of the most used and challenging phrases in the history of Islamic sciences. Commentators, theologians, mystics and philosophers have expressed different views about the identity of viceroy and the succeeded one. The present paper seeks to review and analyze these views in order to identify the correct ones. To this end, it provides a general review on the identity of viceroy and the succeeded one, enumerates and describes different proposed views comprehensively, and judges them based on the analysis of the context of relevant verse and hadiths. It first reviews the concept of the succeeded one and concludes from the analysis of the relevant verse and hadiths that the succeeded one mentioned in the verse is the Most High God. Then it examines possible probabilities and proves that the only accepted probability is that God's viceroy should have special referents and appointed by God

The Impact of Work - Life Balance on Psychological Safety of Staff with the Mediating Role of Organizational Optimism

The present study was conducted to investigate the effect of work- life balance on psychological safety of staff with the mediating role of organizational optimism. The study in terms of purpose is practical and in terms of methods of data collection is survey from group of descriptive researches. The statistical population is female faculty members in the faculties and research institutes of Shahid Beheshti University 163 persons, The number of statistical samples obtained is 65 people. The tool of data collection is questionnaire of work – life balance provided by Agha et al. (2017) and questionnaire of optimism provided by Carver et al. (2010) and questionnaire of psychological safety of staff provided by Maslow (2004). Data analysis was performed with Structural Equation Modeling approach (SEM) with partial least squares method through Smart-PLS 3 software. The findings of this study showed that proposed research model is validated and based on it; Work- life balance has led to organizational optimism and this has an impact on psychological safety of staff. Also, organizational optimism variable plays an intermediary role in the relationship between work – life balance and psychological safety of staff

Performance evaluation of linear variable valve actuation for a linear engine generator

The Joule cycle Linear Engine Generator (LEG) is a promising power generation technology with the potential to achieve zero carbon emissions. However, the LEG expander valve actuation system presents unique challenges due to its lack of a traditional crankshaft, the need for swift valve lift and reversal, and variable lift. This paper presents a Linear Variable Valve Actuation (LVVA) system for a LEG prototype. The LVVA system is powered by voice coil motors. Rigorous experimental investigations were conducted to analyze crucial performance factors, including energy consumption, force balance, energy flow distribution, and the relationship between valve lift duration and energy consumption. The results show that the LVVA system can achieve the desired valve lift and timing, as well as very small variations in LEG performance compared to the model using an ideal lift curve. The LVVA accounts for approximately 3.59 % of the LEG power output. The energy consumption of 1.607 J per valve stroke provides a slight advantage over traditional actuation systems. The obtained optimal lift curves were used to refine the LEG model. The influence of valve lift curves on LEG performance was evaluated which reveals rapid valve openings and relatively short duration contributing to improved LEG performance

Biofabrication of Anisotropic Gold Nanotriangles Using Extract of Endophytic Aspergillus clavatus as a Dual Functional Reductant and Stabilizer

Biosynthesis of metal and semiconductor nanoparticles using microorganisms has emerged as a more eco-friendly, simpler and reproducible alternative to the chemical synthesis, allowing the generation of rare forms such as nanotriangles and prisms. Here, we report the endophytic fungus Aspergillus clavatus, isolated from surface sterilized stem tissues of Azadirachta indica A. Juss., when incubated with an aqueous solution of chloroaurate ions produces a diverse mixture of intracellular gold nanoparticles (AuNPs), especially nanotriangles (GNT) in the size range from 20 to 35 nm. These structures (GNT) are of special interest since they possess distinct plasmonic features in the visible and IR regions, which equipped them with unique physical and optical properties exploitable in vital applications such as optics, electronics, catalysis and biomedicine. The reaction process was simple and convenient to handle and was monitored using ultraviolet–visible spectroscopy (UV–vis). The morphology and crystalline nature of the GNTs were determined from transmission electron microscopy (TEM), atomic force spectroscopy (AFM) and X-ray diffraction (XRD) spectroscopy. This proposed mechanistic principal might serve as a set of design rule for the synthesis of anisotropic nanostructures with desired architecture and can be amenable for the large scale commercial production and technical applications

Biotransformations using Peptostreptococcus productus

EThOS - Electronic Theses Online ServiceGBUnited Kingdo