Distant Phe345 mutation compromises the stability and activity of Mycobacterium tuberculosis isocitrate lyase by modulating its structural flexibility

Isocitrate lyase (ICL), a potential anti-tubercular drug target, catalyzes the first step of the glyoxylate shunt. In the present investigation, we studied the conformational flexibility of MtbICL to better understand its stability and catalytic activity. Our biochemical results showed that a point mutation at Phe345, which is topologically distant (>10 Å) to the active site signature sequence (¹⁸⁹KKCGH¹⁹³), completely abolishes the activity of the enzyme. In depth computational analyses were carried out for understanding the structural alterations using molecular dynamics, time-dependent secondary structure and principal component analysis. The results showed that the mutated residue increased the structural flexibility and induced conformational changes near the active site (residues 170–210) and in the C-terminal lid region (residues 411–428). Both these regions are involved in the catalytic activity of MtbICL. Upon mutation, the residual mobility of the enzyme increased, resulting in a decrease in the stability, which was confirmed by the lower free energy of stabilization in the mutant enzyme suggesting the destabilization in the structure. Our results have both biological importance and chemical novelty. It reveals internal dynamics of the enzyme structure and also suggests that regions other than the active site should be exploited for targeting MtbICL inhibition and development of novel anti-tuberculosis compounds.

Characterization of a Highly pH Stable Chi-Class Glutathione S-Transferase from Synechocystis PCC 6803

Glutathione S-transferases (GSTs) are multifunctional enzymes present in virtually all organisms. Besides having an essential role in cellular detoxification, they also perform various other functions, including responses in stress conditions and signaling. GSTs are highly studied in plants and animals; however, the knowledge regarding GSTs in cyanobacteria seems rudimentary. In this study, we report the characterization of a highly pH stable GST from the model cyanobacterium- Synechocystis PCC 6803. The gene sll0067 was expressed in Escherichia coli (E. coli), and the protein was purified to homogeneity. The expressed protein exists as a homo-dimer, which is composed of about 20 kDa subunit. The results of the steady-state enzyme kinetics displayed protein’s glutathione conjugation activity towards its class specific substrate- isothiocyanate, having the maximal activity with phenethyl isothiocyanate. Contrary to the poor catalytic activity and low specificity towards standard GST substrates such as 1-chloro-2,4-dinitrobenzene by bacterial GSTs, PmGST B1-1 from Proteus mirabilis, and E. coli GST, sll0067 has broad substrate degradation capability like most of the mammalian GST. Moreover, we have shown that cyanobacterial GST sll0067 is catalytically efficient compared to the best mammalian enzymes. The structural stability of GST was studied as a function of pH. The fluorescence and CD spectroscopy in combination with size exclusion chromatography showed a highly stable nature of the protein over a broad pH range from 2.0 to 11.0. To the best of our knowledge, this is the first GST with such a wide range of pH related structural stability. Furthermore, the presence of conserved Proline-53, structural motifs such as N-capping box and hydrophobic staple further aid in the stability and proper folding of cyanobacterial GST- sll0067.

BECLIN1 from Arabidopsis thaliana under the generic control of regulated expression systems, a strategy for developing male sterile plants

Induction of male sterility followed by successful outcrossing is a prerequisite for hybrid seed production. In this article, we have identified a novel use of the BECLIN 1 gene of Arabidopsis, in inducing male sterility in plants, when expressed in the anther tapetum of tobacco. We also report a stringently regulated and high-level expression of the desired gene in tapetum by using a two-component transcription regulation system. The tapetum-specific, two-component transcription system utilizes the TGTA-TBPm³ complementation principle that has been demonstrated by us earlier. We also report a glucocorticoid-dependent expression of AtBECLIN 1 in tapetum, thereby developing glucocorticoid-inducible male sterility in plants.

Draft Genome of the Liver Fluke Fasciola gigantica

Fascioliasis, a neglected foodborne disease caused by liver flukes (genus Fasciola), affects more than 200 million people worldwide. Despite technological advances, little is known about the molecular biology and biochemistry of these flukes. We present the draft genome of Fasciola gigantica for the first time. The assembled draft genome has a size of ∼1.04 Gb with an N50 and N90 of 129 and 149 kb, respectively. A total of 20 858 genes were predicted. The de novo repeats identified in the draft genome were 46.85%. The pathway included all of the genes of glycolysis, Krebs cycle, and fatty acid metabolism but lacked the key genes of the fatty acid biosynthesis pathway. This indicates that the fatty acid required for survival of the fluke may be acquired from the host bile. It may be hypothesized that the relatively larger F. gigantica genome did not evolve through genome duplications but rather is interspersed with many repetitive elements. The genomic information will provide a comprehensive resource to facilitate the development of novel interventions for fascioliasis control.

An improved method for high-level soluble expression and purification of recombinant amyloid-beta peptide for in vitro studies

Amyloid-beta (Aβ) peptide mediates several neurodegenerative diseases. The 42 amino acid (Aβ1-42) is the predominant form of peptide found in the neuritic plaques and has been demonstrated to be neurotoxic in vivo and in vitro. The availability of large quantities of Aβ peptide will help in several biochemical and biophysical studies that may help in exploring the aggregation mechanism and toxicity of Aβ peptide. We report a convenient and economical method to obtain such a peptide biologically. Synthetic oligonucleotides encoding Aβ1-42 were constructed and amplified through the polymerase cycling assembly (also known as assembly PCR), followed by the amplification PCR. Aβ1-42 gene was cloned into pET41a(+) vector for expression. Interestingly, the addition of 3% (v/v) ethanol to the culture medium resulted in the production of large amounts of soluble Aβ fusion protein. The Aβ fusion protein was subjected to a Ni-NTA affinity chromatography followed by enterokinase digestion, and the Aβ peptide was purified using glutathione Sepharose affinity chromatography. The peptide yield was ∼15mg/L culture, indicating the utility of this method for high-yield production of soluble Aβ peptide. Sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis and immunoblotting with anti-His antibody confirmed the identity of purified Aβ fusion protein and Aβ peptide. In addition, this method provides an advantage over the chemical synthesis and other conventional methods used for large-scale production of recombinant Aβ peptide.

Bilateral lipoma arborescens of the subdeltoid bursa

Lipoma arborescens is a rare cause of chronic monoarticular arthritis. It is most commonly seen in the knees, but only a few cases involving other joints, especially the subdeltoid bursa, have been described. To our knowledge, this is the first reported case of lipoma arborescens involving bilateral subdeltoid bursae. Although it is associated with joint effusion, synovial cysts and erosions, the presence of reactive bone formation has not been reported. Magnetic resonance imaging is a very effective method for the diagnosis of this rare condition because of its ability to do tissue characterization.

Functional classification and biochemical characterization of a novel rho class glutathione S-transferase in Synechocystis PCC 6803

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A novel class of glutathione S-transferase (GST) is reported.

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This GST catalyzes dichloroacetate (DCA) degradation and hydroperoxide reactions.

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Functionally this GST is similar to zeta and theta/alpha classes but structurally very different.

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In contrast to other bacterial GSTs, this GST exists as a monomer in solution.

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First report of DCA degradation by any bacterial GST and has potential biotechnological applications.

We report a novel class of glutathione S-transferase (GST) from the model cyanobacterium Synechocystis PCC 6803 (sll1545) which catalyzes the detoxification of the water pollutant dichloroacetate and also shows strong glutathione-dependent peroxidase activity representing the classical activities of zeta and theta/alpha class respectively. Interestingly, sll1545 has very low sequence and structural similarity with these classes. This is the first report of dichloroacetate degradation activity by any bacterial GST. Based on these results we classify sll1545 to a novel GST class, rho. The present data also indicate potential biotechnological and industrial applications of cyanobacterial GST in dichloroacetate-polluted areas.

Recombinant expression, purification and preliminary characterization of the mRNA export factor MEX67 of Saccharomyces cerevisiae

The nuclear export of macromolecules is facilitated by the nuclear pore complexes (NPCs), embedded in the nuclear envelope and consists of multi-protein complexes. MEX67 is one of the nuclear export factor responsible for the transport of the majority of cellular mRNAs from the nucleus to the cytoplasm. The mechanism of mRNA transport through NPCs is unclear due to the unavailability of structures and the known interacting partners of MEX67. The mex67 gene was cloned in pQE30A and was expressed in Escherichia coli. A strategy has been developed to purify the insoluble MEX67 using a nickel affinity column with chelating Sepharose fast flow media, after solubilizing with sodium lauroyl sarcosinate (Sarkosyl). The IMAC purified recombinant MEX67 was further purified using SEC to apparent homogeneity (∼8 mg/L). Following SEC, MEX67 was stable and observed to be a 67 kDa monomeric protein as determined by PAGE and the size exclusion chromatography. The availability of large quantities of the protein will help in its biochemical and biophysical characterization, which may lead to the identification of new interaction partners of MEX67 or MEX67 complex.

Brain MRI features of merosin-negative congenital muscular dystrophy

The purpose of this article is to report brain MRI findings of merosin-negative congenital muscular dystrophy (CMD) in two cases and to discuss its differentiation from other CMD subtypes. The cases were investigated by 1.5 Tesla MRI equipment using T1-weighted, T2-weighted, fluid-attenuated inversion recovery (FLAIR), 3D fast spoiled gradient recalled (SPGR) and post-contrast gadolinium enhanced sequences and the diagnosis was confirmed by muscle biopsy with immunohistochemical staining for merosin. Magnetic resonance imaging showed bilateral subcortical U-fibre white matter changes with periventricular sparing in the first case. Though this imaging finding is non-specific and could be seen in other white matter diseases like Canavan disease, the absence of other distinguishing MRI and clinical features of those conditions allowed a proper diagnosis. The second case showed diffuse subcortical and deep white matter involvement and cerebellar cysts. There was no brainstem involvement, polymicrogyria or cobblestone lissencephaly in both of our cases which allowed differentiation of merosin-negative CMD from other CMDs. Muscle biopsy in both these patients showed dystrophic changes with absent staining for merosin confirming the diagnosis. Merosin-negative CMD should be considered in the imaging differential diagnosis of white matter diseases. In a patient presenting with features of CMD, MRI can be of help in further differentiation of the various CMD subtypes.

Association of postural orthostatic tachycardia syndrome, hypermobility spectrum disorders, and mast cell activation syndrome in young patients; prevalence, overlap and response to therapy depends on the definition

Background

The close association of syndromes of orthostatic intolerance with and without postural orthostatic tachycardia syndrome (POTS) with Joint Hypermobility Disorders (JHD) including Hypermobility Spectrum Disorder (HSD) and hypermobile Ehlers Danlos Syndrome (hEDS) and with Mast Cell Activation Syndrome (MCAS) is now firmly established. However, the prevalence of each entity relative to the other is not well established and is affected greatly by the various definitions used for each syndrome. Use of restricting definitions for each syndrome can be problematic in the clinical setting as it under-estimates the presence of disease, thereby preventing clinicians from considering potentially helpful therapeutic options.

Methods

A retrospective review of the clinical records of 100 young patients meeting POTS criteria was undertaken to determine the frequency of HSD, near-hEDS, and hEDS as well as the frequency of MCAS using consensus-1, conservative consensus-2, and clinical criteria regardless of lab support. Effectiveness of MCAS therapies was assessed in relation to the method of MCAS diagnosis.

Results

From records of 392 patients with orthostatic intolerance syndromes, 100 patients met POTS criteria. The frequency of JHD ranged from 13% using strict criteria of hEDS to 34% using HSD Criteria. The frequency of MCAS ranged from 2% using consensus-1 criteria, to 37% using conservative consensus-2 criteria, to 87% using clinical criteria. Patients diagnosed by clinical criteria with or without the aid of labs responded to therapy similarly to those diagnosed with stricter criteria.

Conclusion

Using overly strict criteria to diagnose conditions which have a high prevalence of co-occurrence misses opportunities for potential therapeutic strategies.

Tabu search problem application based economic impact of coronavirus pandemic on sugar industry inventory system for deteriorating objects with two-distribution center and waste-material treatment

In this paper, the determined economic impact of the Sugar industry of the Coronavirus pandemic for aggravating items with a ramp-type demand with inflation effects in two-Distribution center storage devices and waste-material treatment cost using Taboo Search is developed. The owned Distribution center has a permanent ability of W units; rented Distribution center has unlimited capacity. Here, we hypothesized that the Block chain Economic Impact of the Coronavirus Pandemic Sugar Industry in Inventory Cost of Inventory in RW is greater than that in owned Distribution center using Taboo Search. The shortcomings of the economic impact of the Coronavirus pandemic Sugar industry are allowed and partially lagged behind, and it is assumed that Block chain's economic impact of the Coronavirus Sugar pandemic industry decreases over time with a variable deterioration rate and waste-material treatment cost using Taboo Search. The effect of inflation was also considered due to the different costs associated with Taboo Search applying the Economic Impact of the Coronavirus Sugar Industry Inventory System and waste-material treatment cost using Taboo Search. The mathematical sample is as well used to study the performance of the model using particle size optimization. The cost minimization technique is second-hand to get hold of expressions for total costs and erstwhile parameters.

Characterization, Antioxidant, and Antimicrobial Properties of Mulberry Lattices

In order to find the most advantageous bioactive compounds from mulberry latex for drug development in the near future, this study was conducted to characterize and evaluate antioxidant and antimicrobial properties from four different mulberry lattices (BR-2, S-1, AR-14, and S-146). The characterization of the lattices was performed by scanning electron microscopy with energy-dispersive X-ray spectroscopy, gas chromatography coupled to mass spectroscopy, and Fourier transform infrared spectroscopy. Further, screenings of the antioxidant and antimicrobial potential of selected lattices were performed in vitro using 2,2-diphenyl-1-picrylhydrazyl assay and agar well diffusion methods, respectively. Interestingly, the outcome of the current study revealed that tested mulberry lattices contain a considerable amount of bioactive phytoconstituents, particularly antimicrobial and antioxidant compounds, as revealed by chromatographic analysis. BR-2 latex was found to have significant antioxidant activity (75%) followed by S-146 (64.6%) and AR-14 (52.9%). The maximum antimicrobial activity was found in BR-2 latex compared to other tested latex varieties. The results of this investigation showed that mulberry latex from the BR-2 type may successfully control both bacterial and fungal infections, with the added benefit of having enhanced antioxidant capabilities.

Extreme lateral transcondylar approach to the skull base

In this study, the authors present their experience of using extreme later transcondylar approach (ELTC) for treating 7 patients with lesions in the anterolateral foramen magnum, upper cervical spine and cerebellopontine angle reaching upto jugular foramen. The tumours included meningiomas, neurofibromas (2 cases each), chondrosarcoma, epidermoid and aneurysmal bone cyst (one case each). The approach was used alone, in combination with retrolabyrinthine presigmoid approach in a patient with lower cranial nerve neurofibroma extending extracranially through the jugular foramen, or in combination with partial C1-C3 laminectomy in two patients with meningiomas situated anterolateral to the cord from the foramen magnum to C3. In two patients with extradural vertebral artery (VA) entrapment by a chondrosarcoma and aneurysmal bone cyst respectively, the vertebral artery was ligated distal to the tumour. The tumours were totally excised in five cases and partially in two. There was no preoperative mortality. The major complications included cerebrospinal fluid leak from the wound (3 cases) and increase in lower cranial nerve paresis (2 cases). At follow up, ranging from 6 months to 2 years, 5 patients showed no tumour recurrence. There was improvement in neurological status. One patient, with a partially excised aneurysmal bone cyst, showed no added deficits or increase in the tumour size. However, there was a massive regrowth in the patient with chondrosarcoma after 6 months. This technique provided a wide surgical exposure with direct visualization of the tumour-anterior cord interface, early proximal control of the VA and preservation of lower cranial nerves.

Extended frontobasal approach to the skull base

The extended frontobasal approach provides an adequate midline exposure from the anterior cranial fossa to the sphenoclival region. Between November 1991 and August 1999, 13 patients with extensive anterior and anterolateral skull base tumours extending to supra and parasellar regions, cavernous sinus and sphenoclival regions were operated upon using this approach alone (7 patients) or in combination with subtemporal -infratemporal (4 patients) or transfacial (2 patients) approaches. Gross total excision was performed in 8 patients while in 4 patients with malignant tumours and in a patient with extensive skull base fungal granuloma, only partial excision was possible. Basal repair was performed using pedicled pericranium, temporalis muscle or fascia lata. The complications included increase in the cranial nerve paresis, endophthalmitis, facial oedema, CSF leak, frontal haematoma and internal carotid artery injury. This study reviews the operative technique, the indications and the complications of extended frontobasal approach.