Exploring the potential of T7 bacteriophage protein Gp2 as a novel inhibitor of mycobacterial RNA polymerase

Over the past six decades, there has been a decline in novel therapies to treat tuberculosis, while the causative agent of this disease has become increasingly resistant to current treatment regimens. Bacteriophages (phages) are able to kill bacterial cells and understanding this process could lead to novel insights for the treatment of mycobacterial infections. Phages inhibit bacterial gene transcription through phage-encoded proteins which bind to RNA polymerase (RNAP), thereby preventing bacterial transcription. Gp2, a T7 phage protein which binds to the beta prime (β') subunit of RNAP in Escherichia coli, has been well characterized in this regard. Here, we aimed to determine whether Gp2 is able to inhibit RNAP in Mycobacterium tuberculosis as this may provide new possibilities for inhibiting the growth of this deadly pathogen. Results from an electrophoretic mobility shift assay and in vitro transcription assay revealed that Gp2 binds to mycobacterial RNAP and inhibits transcription; however to a much lesser degree than in E. coli. To further understand the molecular basis of these results, a series of in silico techniques were used to assess the interaction between mycobacterial RNAP and Gp2, providing valuable insight into the characteristics of this protein-protein interaction.

Continuously Varying Critical Exponents Beyond Weak Universality

Renormalization group theory does not restrict the form of continuous variation of critical exponents which occurs in presence of a marginal operator. However, the continuous variation of critical exponents, observed in different contexts, usually follows a weak universality scenario where some of the exponents (e.g., β, γ, ν) vary keeping others (e.g., δ, η) fixed. Here we report ferromagnetic phase transition in (Sm_1−yNd_y)_0.52Sr_0.48MnO₃ (0.5 ≤ y ≤ 1) single crystals where all three exponents β, γ, δ vary with Nd concentration y. Such a variation clearly violates both universality and weak universality hypothesis. We propose a new scaling theory that explains the present experimental results, reduces to the weak universality as a special case, and provides a generic route leading to continuous variation of critical exponents and multi-criticality.

Association of ABO blood group polymorphism and tuberculosis: A study on Bengalee Hindu caste population, West Bengal, India

Tuberculosis (TB) is an infectious disease commonly caused by the bacillus mycobacterium and worldwide estimation demonstrated that more than 8.6 million people are infected by TB. Many of the previous studies reported the association between TB and ABO blood group polymorphism. In this context, the objective of the present study is to understand the association of ABO blood group polymorphism and TB in Bengalee Hindu caste population. The present study consists of 100 clinically diagnosed TB patients and 100 apparently healthy individuals with no previous history of TB from the same population of the same area. The distribution of ABO phenotypes demonstrated significant (p<0.05) excess of AB blood group in TB patients and significant (p<0.05) decrease of O blood group in controls. Logistic regression analysis revealed that individuals with non O blood group have 1.97 times (95% CI 1.04-3.75) greater chance of developing TB than individuals with O blood group.

Primary cutaneous histoplasmosis simulating Molluscum contagiosum

Primary cutaneous histoplasmosis in a HIV positive patient ie isolated cutaneous involvement without any deeper structures is a very rare entity. Only a handful cases have been reported worldwide. This patient presented with cutaneous lesion simulating Molluscum but histopathology revealed Histoplasma capsulatum. The patient had no deep organ involvement. The patient was put on Itraconazole which caused rapid dissolution of the lesions. He was subsequently put on HAART and discharged.

A comparative pharmacokinetic study of a fixed dose combination for essential hypertensive patients: a randomized crossover study in healthy human volunteers

BACKGROUND

This study was aimed to investigate the relative bioavailability of fixed-dose-combination (FDC) product of amlodipine, telmisartan and hydrochlorothiazide with individual marketed products in healthy male volunteers. Control of blood pressure with fixed dose combination of the above drugs acting through different mechanism have a benefit of convenient dosing in terms of compliance, lower the dose and subsequently reduce the side effects.

METHODS

The authors investigated the relative bioavailability under a fasting state of the 3 drugs in a randomized, open-label, 2-treatment, 2-period, 2-sequence, crossover bioequivalence study with a washout period of 21 days. Plasma concentration of the analytes were assayed in timed samples with a simple, highly sensitive and rapid validated method using HPLC coupled to tandem mass spectrometry that had a lower limit of quantification of 1 ng/mL for all the 3 components.

RESULTS

Test and reference formulations gave a mean Cmax of 5.234±0.914 ng/mL and 4.991±0.563 ng/mL, 108.839±13.601 ng/mL and 114.783±12.315 ng/mL and 97.814±10.779 ng/mL and 93.731±10.018 ng/mL for amlodipine, telmisartan and hydrochlorothiazide respectively. The AUC0-t of amlodipine, telmisartan and hydrochlorothiazide was 161.484 ng.h/mL, 1 917.644 ng.h/mL and 822.847 ng.h/mL for test formulation and 162.108 ng.h/mL, 2 014.764 ng.h/mL and 829.323 ng.h/mL for reference in the fasting state.

CONCLUSION

The 90% confidence intervals for the test/reference ratio of the pharmacokinetic parameters in fasting state (mean Cmax, AUC0-t, and AUC0-∞) were within the acceptable range of 80.00-125.00. Thus, these findings clearly indicate that the FDC product is bioequivalent with the individual marketed products in terms of rate and extent of drug absorption and is well tolerated with no significant adverse reactions.

The protective effect of astrocyte-derived 14,15-epoxyeicosatrienoic acid on hydrogen peroxide-induced cell injury in astrocyte-dopaminergic neuronal cell line co-culture

Astrocytes perform several functions that are essential for normal neuronal activity. They play a critical role in neuronal survival during ischemia and other degenerative injuries and also modulate neuronal recovery by influencing neurite outgrowth. In this study, we investigated the neuroprotective effects of astrocyte-derived 14,15-epoxyeicosatrienoic acid (14,15-EET), metabolite of arachidonic acid by cytochrome P450 epoxygenases (CYP), against oxidative stress induced by hydrogen peroxide (H(2)O(2)). We found that dopaminergic neuronal cells (N27 cell line) stimulated with two different doses of H(2)O(2) (0.1 and 1mM) for 1h showed decreased cell viability compared to the control group, while astrocytes showed less cell death after stimulation with the same doses of H(2)O(2) for 1h. Dopaminergic neuronal cells (N27 cell line) pretreated with different doses of 14,15-EET (0.1-30 μM, 30 min) before H(2)O(2) stimulation also showed increased cell viability. Furthermore, pre-treatment of the co-cultured cells with 12-(3-adamantan-1-yl-ureido)-dodecanoic acid, an inhibitor of the EET metabolizing enzyme, soluble epoxide hydrolase (sEH), before H(2)O(2) stimulation (1mM, for 1h) increased cell viability. It also increased the endogenous level of 14,15-EET in the media compared to control group. However, pretreatment with the CYP epoxygenase inhibitor miconazole (1-20 μM, 1h) before H(2)O(2) (1mM, 1h) stimulation showed decreased cell viability. Our data suggest that 14,15-EET which is released from astrocytes, enhances cell viability against oxidant-induced injury. Further understanding of the mechanism of 14,15-EET-mediated protection in dopaminergic neurons is imperative, as it could lead to novel therapeutic approaches for treating CNS neuropathologies, such as Parkinson's disease.

Differential effect of amyloid β on the cytochrome P450 epoxygenase activity in rat brain

One of the prominent features of Alzheimer's disease is the excessive accumulation of the protein amyloid beta (Aβ) in certain areas of the brain leading to neurodegeneration. Aβ is cytotoxic and disrupts several cytoprotective pathways. Recent literature has demonstrated that certain cytochrome P450 (CYP) products are neuroprotective, including epoxide metabolites of arachidonic acid (AA), epoxyeicosatrienoic acids (EETs). The action of Aβ with respect to regionally produced EETs in the brain has yet to be defined. Epoxygenases metabolize AA into four regioisomers of EETs (14,15-, 11,12-, 8,9- and 5,6-EET). EETs are rapidly degraded into dihydroxyeicosatrienoic acids (DiHETEs) by soluble epoxide hydrolase (sEH). To determine the effect of Aβ on the epoxygenase activity in different regions of the brain, microsomes were prepared from the cerebrum and cerebellum of adult Sprague-Dawley rats and incubated with 1 and 10 μM Aβ for 30 min after which epoxygenase activity assay was performed. Mass spectrometry indicated that incubation with Aβ reduced 14,15-EET production by 30% as compared to vehicle in the cerebrum, but not in the cerebellum. When we separated the cerebrum into cortex and hippocampus, significant decrease in the production of total EETs and DiHETEs were seen in presence of Aβ (81% and 74%) in the cortex. Moreover, 11,12-EET production was decreased to ∼70% of vehicle in both cortex and hippocampus. Epoxygenase activity in the cultured astrocytes and neurons also showed reduction in total EET and DiHETE production (to 80% and ∼70% of vehicle respectively) in presence of Aβ. Altogether, our data suggest that Aβ reduces epoxygenase activity differentially in a region-specific and cell-specific manner. The reduction of cytoprotective EETs by Aβ in the cerebrum may make it more prone to degeneration than the cerebellum. Further understanding of these interactions will improve our ability to protect against the pathology of Alzheimer's disease.

Single molecule immunoassay on plasmonic platforms

We examined the photophysical properties of the new near infrared (NIR) fluorescent label SeTau-665 on a plasmonic platform of self- assembled colloidal structures (SACS) of silver prepared on a semitransparent silver film. A SeTau-665 immunoassay was performed on this platform and a control glass slide. The fluorescence properties of this label substantially change due to plasmonic interactions. While the average brightness increase of SeTau 665 in ensemble measurements was about 70-fold, fluorescence enhancements up to four-hundred times were observed on certain "hot spots" for single molecule measurements. The intensity increase is strongly correlated with a simultaneous decrease in fluorescence lifetime in these "hot spots". The large increase in brightness allows the reduction of the excitation power resulting in a reduced background and increased photostability. The remarkable fluorescence enhancements observed for SeTau 665 on our plasmonic platform should allow to substantially improve single molecule detection and to reduce the detection limits in sensing devices.

Audit of hepatitis B vaccination of men who have sex with men attending Scottish genitourinary medicine clinics

Practice related to hepatitis B vaccination of men who have sex with men (MSM) in Scottish genitourinary medicine clinics was audited against targets based on the offer and completion of vaccination set by the British Association of Sexual Health and HIV. Of 521 cases audited from 11 clinics, 215 (41%) were eligible for vaccination and 175 (81%) of eligible MSM were offered vaccination. Of those, 144 (82%) accepted vaccination. The super-accelerated schedule was most commonly prescribed but only 29% of those starting this schedule completed it, compared with 57% of those receiving the standard course. The overall vaccination completion rate was 31% and 82% of those completing vaccination had antisurface antibodies measured. A more robust recall system and uniformity in vaccination policies addressing the balance of patient compliance and immunogenicity of vaccine schedule are needed to improve completion rates.

A Comparative Analysis of Immunorestoration and Recovery with Conventional and Immunotherapeutic Protocols in Canine Generalized Demodicosis: A Newer Insight of Immunotherapeutic Efficacy of T11TS

Demodex canis is a natural inhabiting mite of canine skin. Immunological disorder or genetic disorder induces the Demodex population to proliferate vigorously resulting in generalized demodicosis with consequent chronic immunosuppression. Signs of generalized demodicosis include alopecia, crysting, erythema, secondary pyoderma etc. Amitraz, an acaricide, is used conventionally for the treatment of generalized demodicosis. In many instances, the disease relapses due to the residual immunosuppression. The need of an immunorestorative therapy has been urged in generalized demodicosis. Two immunorestorative drugs, namely, Immuplus, a herbal drug, and T11TS, a sheep erythrocyte surface glycoprotein, has been used in two separate groups of dogs having generalized demodicosis and receiving Amitraz treatment. It was observed that though Amitraz treated group responded to the therapy showing increased E-rosettes and nonspecific cytotoxic efficacy of T-lymphocytes and decrease in phagocytic potential of macrophages, the groups treated with the immunotherapeutics like Immuplus and T11TS, responded better. However, the group treated with T11TS showed best recovery. These results emphasize the need for an immunorestorative therapy in generalized demodicosis and provide data in favor of T11TS as a better immunomodulator in comparison to Immuplus.

Label-free in situ imaging of lignification in the cell wall of low lignin transgenic Populus trichocarpa

Chemical imaging by confocal Raman microscopy has been used for the visualization of the cellulose and lignin distribution in wood cell walls. Lignin reduction in wood can be achieved by, for example, transgenic suppression of a monolignol biosynthesis gene encoding 4-coumarate-CoA ligase (4CL). Here, we use confocal Raman microscopy to compare lignification in wild type and lignin-reduced 4CL transgenic Populus trichocarpa stem wood with spatial resolution that is sub-microm. Analyzing the lignin Raman bands in the spectral region between 1,600 and 1,700 cm(-1), differences in lignin signal intensity and localization are mapped in situ. Transgenic reduction of lignin is particularly pronounced in the S2 wall layer of fibers, suggesting that such transgenic approach may help overcome cell wall recalcitrance to wood saccharification. Spatial heterogeneity in the lignin composition, in particular with regard to ethylenic residues, is observed in both samples.