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The L-arginine biosynthesis pathway consists of eight enzymes that catalyse the conversion of L-glutamate to L-arginine. Arginine auxotrophs (argB/argF deletion mutants) of Mycobacterium tuberculosis are rapidly sterilised in mice, while inhibition of ArgJ with Pranlukast was found to clear chronic M. tuberculosis infection in a mouse model. Enzymes in the arginine biosynthetic pathway have therefore emerged as promising targets for anti-tuberculosis drug discovery. In this work, the ligandability of four enzymes of the pathway ArgB, ArgC, ArgD and ArgF is assessed using a fragment-based approach. We identify several hits against these enzymes validated with biochemical and biophysical assays, as well as X-ray crystallographic data, which in the case of ArgB were further confirmed to have on-target activity against M. tuberculosis. These results demonstrate the potential for more enzymes in this pathway to be targeted with dedicated drug discovery programmes.

• Carbon neutral concrete production is future of construction industry. • RSM is a well-known mathematical or statistical predictive tool. • Optimum use of waste materials in combination with fibers can help in developing sustainable concrete. • RSM has been used to forecast the desired qualities of concrete by obtaining an optimal mixed proportion. Globally, significant attempts have been made to properly utilize waste materials and various by-products as supplementary cementitious materials (SCMs) in the production of sustainable concrete. Fly ash and alkali resistance Glass Fiber (ARGF) are two ingredients that can help to improve the overall performance of concrete and mortars. The main objective of this study is to use Response Surface Methodology (RSM) to predict and optimize the fresh and mechanical properties of modified concrete made in combination with Fly Ash as a cement alternative and ARGF as extra reinforcing material. The different percentages of both materials Fly ash and ARGF were chosen as design factors to develop statistical models for the responses of fresh and mechanical parameters at 7 and 28 days. The experimental runs were carried out utilizing Central Composite Design (CCD), and there was a strong connection between the actual and estimated values. At a 95 % level of confidence, the effect of multiple factors on the target response was studied using statistical analysis of ANOVA results. The coefficient of determination (R2) values ranging from 0.82 to 0.99 show the reliability and performance of the proposed model. The optimal nine responses values for the slump, 7D-CS, 28D-CS, 7D-STS, 28D-STS, 7D-FS, 28D-FS, 7D-UPV and 28D-UPV were 41.70, 1820.51, 2177.23,291.86, 378.85, 589.656, 756.58, 3.82, and 4.34 with desirability value of 0.918. The linearity of the data points surrounding the line of fit for each mix blends indicating the model's efficiency in estimating the nine responses. This study will help in optimization of concrete mix design using waste materials and fibers. [ABSTRACT FROM AUTHOR]

Recombination is well known as a complicating factor in the interpretation of molecular phylogenies. Here we describe a maximum likelihood sliding window method based on a likelihood ratio test for scanning DNA sequence alignments for regions of incongruent phylogenetic signals, such as those influenced by recombination. Using this method, we identify several instances of gene conversion between paralogous chaperonin genes in euryarchaeote Archaea, many of which are not detected by two other widely used methods. In the Thermococcus/Pyrococcus lineage, where a gene duplication producing a and b paralogues predates the divergence of Thermococcus strains KS-1 and KS-8, gene conversion has homogenized portions of the a and b genes in KS-8 since the divergence of these two strains. A region near the 3′ end of the a and b paralogues in the methanogen Methanobacterium thermoautotrophicum also appears to have undergone gene conversion. We apply the method to two additional test data sets, the argF gene of Neisseria and a set of actin paralogues in maize, and show that it successfully identifies all the recombinant regions that were previously detected with other methods. Our approach is relatively insensitive to the presence of divergent sequences in the alignment, making it ideal for detecting recombination between both closely and distantly related genes. [ABSTRACT FROM AUTHOR]

Ornithine carbamoyl transferase (OCT), encoded by argF, catalyzes the formation of citrulline from ornithine and carbamoyl phosphate. A presumptive argF from the filamentous cyanobacterium Nostoc sp. PCC 73102 has been cloned and sequenced. A transcriptional terminator sequence is suggested downstream of the structural gene. Amino acids known to be involved in binding the substrate carbamoyl phosphate and ornithine were observed within the sequence. The deduced amino acid sequence showed 69% identity to the deduced amino acid sequence from Synechocystis sp. PCC 6803, but less identities (30-46@) to OCTs from other organisms. The subunits of the deduced protein had a calculated molecular mass of 33 368 Da. Northern blot experiments demonstrated a single transcript with an approximate size of 0.95 kb. [ABSTRACT FROM AUTHOR]

Mycobacterium bovis (M. bovis) is a member of mycobacterium tuberculosis complex (MTBC), and a causative agent of chronic respiratory disease in a wide range of hosts. Bacillus Calmette-Guerin (BCG) vaccine is mostly used for the prevention of childhood tuberculosis. Further substantial implications are required for the development and evaluation of new tuberculosis (TB) vaccines as well as improving the role of BCG in TB control strategies. In this study, we prepared PLGA nanoparticles encapsulated with argF antigen (argF-NPs). We hypothesized, that argF nanoparticles mediate immune responses of BCG vaccine in mice models of M. bovis infection. We observed that mice vaccinated with argF-NPs exhibited a significant increase in secretory IFN-γ, CD4+ T cells response and mucosal secretory IgA against M. bovis infection. In addition, a marked increase was observed in the level of secretory IL-1β, TNF-α and IL-10 both in vitro and in vivo upon argF-NPs vaccination. Furthermore, argF-NPs vaccination resulted in a significant reduction in the inflammatory lesions in the lung's tissues, minimized the losses in total body weight and reduced M. bovis burden in infected mice. Our results indicate that BCG prime-boost strategy might be a promising measure for the prevention against M. bovis infection by induction of CD4+ T cells responses and mucosal antibodies. Recombinant argF nanoparticles exhibited an enhanced secretory IFN-γ, CD4+ T cells response and mucosal secretory IgA against M. bovis infection in BCG-primed mice. The argF-NPs vaccination reduced pathological lesions and bacterial burden in the spleens and lungs of infected mice. This study suggests that the argF-nanoparticles could be exploited as an effective candidate in the development of vaccine to augment BCG induced immunity. [Display omitted] • Prepared PLGA nanoparticles encapsulating the argF antigen against M. bovis infection. • The argF-NPs shows significant protections in infected BCG- immunized mice. • The argF-NPs could be exploited as an effective candidate to augment BCG induced immunity. [ABSTRACT FROM AUTHOR]

The L-arginine biosynthesis pathway consists of eight enzymes that catalyse the conversion of L-glutamate to L-arginine. Arginine auxotrophs (argB/argF deletion mutants) of Mycobacterium tuberculosis are rapidly sterilised in mice, while inhibition of ArgJ with Pranlukast was found to clear chronic M. tuberculosis infection in a mouse model. Enzymes in the arginine biosynthetic pathway have therefore emerged as promising targets for anti-tuberculosis drug discovery. In this work, the ligandability of four enzymes of the pathway ArgB, ArgC, ArgD and ArgF is assessed using a fragment-based approach. We identify several hits against these enzymes validated with biochemical and biophysical assays, as well as X-ray crystallographic data, which in the case of ArgB were further confirmed to have on-target activity against M. tuberculosis . These results demonstrate the potential for more enzymes in this pathway to be targeted with dedicated drug discovery programmes., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2021 The Author(s).)