Statistical optimalization of α-Amylase production from Penicillium notatum NCIM 923 and kinetics study of the purified enzyme

In this study, response surface methodology (RSM) was employed to optimize the production of α-amylase by Penicillium notatum NCIM 923 through solid-state fermentation. The individual and combinational effects of the factors, i.e. substrate amount, initial moisture, fermentation time, temperature and size of inoculum were found to have significant effects on α-amylase production: the optimum values of the tested variables were 5 g, 70%, 94 h, 28 °C and 20%, respectively. The predicted amylase production (2819.24 U/g) was in good agreement with the value measured under optimized surrounding (2810.33 U/g). The molecular mass of purified α-amylase was about 52 kDa. The enzyme activity exhibited its pH optimum between pH 4.6 and 6.6, and it had maximal activity at 50 °C. The apparent Km and Vmax of α-amylase for starch were 4.1 mg/ml and 247.6 μmol/min, respectively. The activation energy (Ea) for starch hydrolysis was found to be 14.133 kJ/mol. The enzyme was thermostable with half-life (t1/2) of 110 min at 80 °C and temperature coefficient (Q10) value of 1.0. Purified enzyme was activated by Ca2+ and inhibited by Hg2+ ions. EDTA also inhibited the enzyme activity, indicating that the purified enzyme is a metalloenzyme

Presentation of mania in a case of scrub typhus

Scrub Typhus that is caused by Orienta tsutsugamushi is a zoonotic disease found commonly in north east zone of India. It is also known as tsutsugamushi fever as it clinically appears as an acute febrile illness with significant lethality if not treated timely. Neurological consequences are though very rare can occur in this illness. Here we present a case of 25 years old female with a history of tsutsugamushi fever developing organic manic disorder as a consequence of the illness

Methamphetamine abuse in the form of yaba pills

YABA, also known as “Nazi speed” is a relatively newer stimulant drug with abusive potential that contains methamphetamine and caffeine in various proportions and mostly available in Bangladesh and its subcontinent and relatively rare in Indian states. Here, we report a case of a 30-year-old male with history of Yaba abuse for the past 4 years currently complaining of withdrawal symptoms palpitation, dry mouth, irritability, and mood symptoms that managed symptomatically and with topiramate tablets to prevent future relapse

A Rapid and Easy-to-Perform Method of Nucleic-Acid Based Dengue Virus Diagnosis Using Fluorescence-Based Molecular Beacons

Detecting dengue virus (DENV) infection in patients as early as possible makes the disease management convenient. Conventionally, DENV infection is diagnosed by ELISA-based methods, but sensitivity and specificity are major concerns. Reverse-transcription-PCR (RT-PCR)-based detection confirms the presence of DENV RNA; however, it is expensive, time-consuming, and skilled personnel are required. A fluorescence-based detection system that detects DENV RNA in patient’s serum directly, without any nucleic acid amplification step, has been developed. The method uses target-specific complementary sequence in the molecular beacon, which would specifically bind to the DENV RNA. The molecular beacons are approximately 40 bases long hairpin structures, with a fluorophore-quencher system attached at the terminal ends of the stem. These probes are biotinylated in the stem region, so that they can be immobilized on the streptavidin-tagged magnetic beads. These magnetic beads, coupled with biotinylated molecular beacons, are used for the detection of the target RNA in the serum by incubating the mixture. After incubation, beads are separated and re-suspended in a buffer. The measurement of fluorescence is taken in fluorometer after 15 min incubation at 50 °C. The whole work is carried out in a single tube. This rapid method can precisely detect dengue RNA within two hours, confirming ongoing DENV replication in the patient

Dermatitis artefacta in the patients of obsessive compulsive disorder: A case series

Dermatitis artefacta or factitious dermatitis is a psychodermatological disorder commonly found in dermatology and psychiatric departments. Comorbid psychiatric disorders are frequently seen with this conditions and proper meticulous history and evaluation both from dermatology and psychiatric point of view is needed to make this diagnosis of exclusion. There are no definite diagnostic criteria or treatment protocols for the above conditions and a combination of psychiatric dermatological and psychological approach is needed to manage this. Lack of proper clinical knowledge and awareness regarding the condition may lead to misdiagnosed the cases frequently. Here we have reported the three cases of dermatitis artefacta with comorbid obsessive compulsive disorder

Molecular basis of VEGFR1 autoinhibition at the plasma membrane

Abstract Ligand-independent activation of VEGFRs is a hallmark of diabetes and several cancers. Like EGFR, VEGFR2 is activated spontaneously at high receptor concentrations. VEGFR1, on the other hand, remains constitutively inactive in the unligated state, making it an exception among VEGFRs. Ligand stimulation transiently phosphorylates VEGFR1 and induces weak kinase activation in endothelial cells. Recent studies, however, suggest that VEGFR1 signaling is indispensable in regulating various physiological or pathological events. The reason why VEGFR1 is regulated differently from other VEGFRs remains unknown. Here, we elucidate a mechanism of juxtamembrane inhibition that shifts the equilibrium of VEGFR1 towards the inactive state, rendering it an inefficient kinase. The juxtamembrane inhibition of VEGFR1 suppresses its basal phosphorylation even at high receptor concentrations and transiently stabilizes tyrosine phosphorylation after ligand stimulation. We conclude that a subtle imbalance in phosphatase activation or removing juxtamembrane inhibition is sufficient to induce ligand-independent activation of VEGFR1 and sustain tyrosine phosphorylation

In Situ Mechanistic Insights for the Oxygen Reduction Reaction in Chemically Modulated Ordered Intermetallic Catalyst Promoting Complete Electron Transfer

The well-known limitation of alkaline fuel cells is the slack kinetics of the cathodic half-cell reaction, the oxygen reduction reaction (ORR). Platinum, being the most active ORR catalyst, is still facing challenges due to its corrosive nature and sluggish kinetics. Many novel approaches for substituting Pt have been reported, which suffer from stability issues even after mighty modifications. Designing an extremely stable, but unexplored ordered intermetallic structure, Pd$_2$Ge, and tuning the electronic environment of the active sites by site-selective Pt substitution to overcome the hurdle of alkaline ORR is the main motive of this paper. The substitution of platinum atoms at a specific Pd position leads to Pt$_{0.2}$Pd$_{1.8}$Ge demonstrating a half-wave potential (E$_{1/2}$) of 0.95 V vs RHE, which outperforms the state-of-the-art catalyst 20% Pt/C. The mass activity (MA) of Pt$_{0.2}$Pd$_{1.8}$Ge is 320 mA/mg$_{Pt}$, which is almost 3.2 times better than that of Pt/C. E$_{1/2}$ and MA remained unaltered even after 50,000 accelerated degradation test (ADT) cycles, which makes it a promising stable catalyst with its activity better than that of the state-of-the-art Pt/C. The undesired 2e$^–$ transfer ORR forming hydrogen peroxide (H$_2$O$_2$) is diminished in Pt$_{0.2}$Pd$_{1.8}$Ge as visible from the rotating ring-disk electrode (RRDE) experiment, spectroscopically visualized by in situ Fourier transform infrared (FTIR) spectroscopy and supported by computational studies. The effect of Pt substitution on Pd has been properly manifested by X-ray absorption spectroscopy (XAS) and X-ray photoelectron spectroscopy (XPS). The swinging of the oxidation state of atomic sites of Pt$_{0.2}$Pd$_{1.8}$Ge during the reaction is probed by in situ XAS, which efficiently enhances 4e$^–$ transfer, producing an extremely low percentage of H$_2$O$_2$

Morphology‐Tuned Pt3_3Ge Accelerates Water Dissociation to Industrial‐Standard Hydrogen Production over a wide pH Range

The discovery of novel materials for industrial-standard hydrogen production is the present need considering the global energy infrastructure. A novel electrocatalyst, Pt$_3$Ge, which is engineered with a desired crystallographic facet (202), accelerates hydrogen production by water electrolysis, and records industrially desired operational stability compared to the commercial catalyst platinum is introduced. Pt$_3$Ge-(202) exhibits low overpotential of 21.7 mV (24.6 mV for Pt/C) and 92 mV for 10 and 200 mA cm$^{−2}$ current density, respectively in 0.5 m H$_2$SO$_4$. It also exhibits remarkable stability of 15 000 accelerated degradation tests cycles (5000 for Pt/C) and exceptional durability of 500 h (@10 mA cm$^{−2}$) in acidic media. Pt$_3$Ge-(202) also displays low overpotential of 96 mV for 10 mA cm$^{−2}$ current density in the alkaline medium, rationalizing its hydrogen production ability over a wide pH range required commercial operations. Long-term durability (>75 h in alkaline media) with the industrial level current density (>500 mA cm$^{−2}$) has been demonstrated by utilizing the electrochemical flow reactor. The driving force behind this stupendous performance of Pt$_3$Ge-(202) has been envisaged by mapping the reaction mechanism, active sites, and charge-transfer kinetics via controlled electrochemical experiments, ex situ X-ray photoelectron spectroscopy, in situ infrared spectroscopy, and in situ X-ray absorption spectroscopy further corroborated by first principles calculations

Tcf-1 promotes genomic instability and T cell transformation in response to aberrant β-catenin activation

Understanding the mechanisms promoting chromosomal translocations of the rearranging receptor loci in leukemia and lymphoma remains incomplete. Here we show that leukemias induced by aberrant activation of β-catenin in thymocytes, which bear recurrent Tcra/Myc-Pvt1 translocations, depend on Tcf-1. The DNA double strand breaks (DSBs) in the Tcra site of the translocation are Rag-generated, whereas the Myc-Pvt1 DSBs are not. Aberrantly activated β-catenin redirects Tcf-1 binding to novel DNA sites to alter chromatin accessibility and down-regulate genome-stability pathways. Impaired homologous recombination (HR) DNA repair and replication checkpoints lead to retention of DSBs that promote translocations and transformation of double-positive (DP) thymocytes. The resulting lymphomas, which resemble human T cell acute lymphoblastic leukemia (T-ALL), are sensitive to PARP inhibitors (PARPis). Our findings indicate that aberrant β-catenin signaling contributes to translocations in thymocytes by guiding Tcf-1 to promote the generation and retention of replication-induced DSBs allowing their coexistence with Rag-generated DSBs. Thus, PARPis could offer therapeutic options in hematologic malignancies with active Wnt/β-catenin signaling

Suppression of poised oncogenes by ZMYND8 promotes chemo-sensitization

The major challenge in chemotherapy lies in the gain of therapeutic resistance properties of cancer cells. The relatively small fraction of chemo-resistant cancer cells outgrows and are responsible for tumor relapse, with acquired invasiveness and stemness. We demonstrate that zinc-finger MYND type-8 (ZMYND8), a putative chromatin reader, suppresses stemness, drug resistance, and tumor-promoting genes, which are hallmarks of cancer. Reinstating ZMYND8 suppresses chemotherapeutic drug doxorubicin-induced tumorigenic potential (at a sublethal dose) and drug resistance, thereby resetting the transcriptional program of cells to the epithelial state. The ability of ZMYND8 to chemo-sensitize doxorubicin-treated metastatic breast cancer cells by downregulating tumor-associated genes was further confirmed by transcriptome analysis. Interestingly, we observed that ZMYND8 overexpression in doxorubicin-treated cells stimulated those involved in a good prognosis in breast cancer. Consistently, sensitizing the cancer cells with ZMYND8 followed by doxorubicin treatment led to tumor regression in vivo and revert back the phenotypes associated with drug resistance and stemness. Intriguingly, ZMYND8 modulates the bivalent or poised oncogenes through its association with KDM5C and EZH2, thereby chemo-sensitizing the cells to chemotherapy for better disease-free survival. Collectively, our findings indicate that poised chromatin is instrumental for the acquisition of chemo-resistance by cancer cells and propose ZMYND8 as a suitable epigenetic tool that can re-sensitize the chemo-refractory breast carcinoma