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Exploitation of in Situ Generated Sugar-Based Olefin Keto-Nitrones: Synthesis of Carbocycles, Heterocycles, and Nucleoside Derivatives
No full textApplication of intramolecular 1,3-dipolar nitrone
cycloaddition reaction on carbohydrate-derived precursors
containing an olefin functionality at C-1 or C-3 or C-5 and a nitrone moiety at C-2 or C-3 as appropriate has resulted in the formation of structurally new cycloaddition products containing furanose-fused oxepane, thiepane, azepane, cyclopentane, cycloheptane, tetrahydrofuran, and pyranose-fused tetrahydrofuran rings. The structure and stereochemistry of these products have been characterized by spectral as well as single-crystal X-ray analyses. Two of the compounds have been transformed to the bicyclic nucleoside derivatives applying Vorbrüggen reaction
conditions
Merging C−H Activation and Alkene Difunctionalization at Room Temperature: A Palladium-Catalyzed Divergent Synthesis of Indoles and Indolines
No full textA palladium-catalyzed 1,2-carboamination through C−H activation at room temperature is reported for the synthesis of 2-arylindoles, and indolines from readily
available, inexpensive aryl ureas and vinyl arenes. The reaction initiates with a urea-directed electrophilic ortho palladation, alkene insertion, and β-hydride elimination sequences to provide the Fujiwara−Moritani arylation product. Subsequently, aza-Wacker cyclization, and β-hydride elimination provide the 2-arylindoles in high yields. Intercepting the common σ-alkyl-Pd intermediate, corresponding indolines are also achieved. The indoline formation is attributed to the generation of stabilized, cationic π-benzyl-Pd species to suppress β-hydride elimination
Lipid from Infective L. donovani Regulates Acute Myeloid Cell Growth via Mitochondria Dependent MAPK Pathway
No full textThe microbial source, which includes live, attenuated, or genetically modified microbes or their cellular component(s) or metabolites, has gained increasing significance for therapeutic intervention against several pathophysiological conditions of disease including leukemia, which remains an incurable disease till now despite recent advances in the medical sciences. We therefore took up the present study to explore if the leishmanial lipid (pLLD) isolated from L. donovani can play an anti-neoplastic role in acute myeloid leukemia cells by regulating cellular growth. Indeed pLLD significantly inhibited cell proliferation of four AML
cell lines (HL-60, MOLT-4, U937, and K562). Scanning electron microscopy and DNA fragmentation analysis revealed that it significantly induced apoptosis of U937 cells through morphological alteration. Occurrence of apoptosis was checked by using Annexin exposure and this established that the cell cycle was arrested at G0/G1 phase in time-dependent manner. pLLD increased the intracellular ROS with alteration of mitochondrial membrane potential, as detected using DCFDA. It also regulated the expression of apoptosis-related proteins like Bax, Bcl2, Bad and t-Bid besides causing cleavage of PARP as determined by western blot analysis. Treatment of U937 cells with pLLD induced the activation of extracellular signal-regulated kinase (ERK)1/2, c-Jun N-terminal kinase (JNK)1/2, p38, and caspases
9/3. The results suggest that pLLD induces apoptosis in acute myeloid leukemia cells possibly via increasing intracellular ROS and regulating the MAPK pathwa
Post translational Modulations of PTEN and Their Implication in Cancer
No full textPTEN since its identification has been in large associated with the control of human malignancies. The dominance of PTEN over the PI3K signaling cascade is mainly
responsible for rendering it the tumor suppressive role that results in the control of a wide array of physiological processes; growth, apoptosis, proliferation and migration. However, in recent years, PTEN has expanded its TENtacles in regulating processes like stem cell
population maintenance, genomic stability regulation and activation of ovarian follicle. Meanwhile, PTEN protein phosphatase activity has gained significant importance and is even capable of inhibiting cell migration irrespective of the Akt pathway. As a protein phosphatase, it targets among others SRC kinases, CREB in the nucleus thereby regulating migration of glioma cells. Crucial for PTEN to be able to render its functions properly is the
ability to translocate to different sub-cellular compartments of the cell and even out of it
through exosomes while retaining its phosphatase activity in the cells where it is internalized. Justifiably, PTEN has fast attained the stature of one of the prime regulators of the cell and therefore it needs to be subjected to intricate surveillance. Although, PTEN like other major players of the cell shows regulation at the transcriptional level as well as through epigenetic silencing, post-translational modifications of PTEN and
the associated localization based alterations in its activities have been the focal point of research on PTEN regulatory events. There have been reports that suggest for negligible PTEN expression although the transcript levels seemed to be good enough. Thus, this study aims to delineate the post-translational modulations of PTEN and their implication in cancer. The first two parts of the work provide insights into the post-translational
regulation of PTEN mainly by ubiquitination and ubiquitination-phosphorylation crosstalk. While in the third part, a strategy to stabilize PTEN has been established through an exosomes-mediated delivery of the intrinsic C-terminus domain of PTEN that causes tumor
inhibition. In the first part of the study, we show that CHIP, the chaperone-associated E3 ligase induces ubiquitination and proteasomal degradation of PTEN as well as regulates the turnover of the protein. It was apparent from our findings that PTEN transiently associates
with the molecular chaperones and thereby gets diverted to the degradation pathway through its interaction with CHIP. The TPR domain of CHIP and parts of the N-terminal
domain of PTEN are required for their interaction. Overexpression of CHIP leads to elevated ubiquitination and a shortened half-life of endogenous PTEN. On the other hand,
depletion of endogenous CHIP stabilizes PTEN. CHIP is also shown to regulate PTENdependent transcription presumably through its downregulation. PTEN shared an inverse
correlation with CHIP in human prostate cancer patient samples thereby triggering the prospects of a more complex mode of PTEN regulation in cancer.PTEN mutation is a frequent feature across a plethora of human cancers, the hot-spot being its C-terminus (CT) regulatory domain resulting in a much diminished level of protein expression. In the second part of the work, the presence of C-terminus mutations was confirmed through sequencing of different human tumor samples. CKII-mediated phosphorylation of PTEN at these sites makes it a loopy structure competing with the E3 ligases for binding to its lipid anchoring C2 domain. Accordingly, it was found that PTEN-CT
expressing stable cell lines could inhibit tumorigenesis in syngenic breast tumor mice models. The third part shows the strategy to design a novel exosome-mediated delivery of the
intrinsic PTEN domain, PTEN-CT into different cancer cells and observed reduced proliferation, migration and colony forming ability. The delivery of exosome containing
PTEN-CT to breast tumor mice model was found to result in significant regression in tumor size with the tumor sections showing increased apoptosis. Here, we also report for the first time an active PTEN when its C2 domain is bound by PTEN-CT, probably rendering its antitumorigenic
activities through the protein phosphatase activity. Therefore, therapeutic interventions that focuses on PTEN E3 ligase inhibition through exosome-mediated PTENCT
delivery can be a probable route in the treatment of cancers with low PTEN expression. Altogether, the findings emanating from this research work could be useful in designing therapeutic strategies against cancers showing low or negligible PTEN expression
Arsenic Exposure through Drinking Water Leads to Senescence and Alteration of Telomere Length in Humans: A Case-Control Study in West Bengal, India
No full textArsenic (As) induces pre-malignant and malignant dermatological lesions, non-dermatological health effects and cancers
in humans. Senescence involves telomere length changes and acquisition of senescence-associated secretory phenotype
(SASP), which promotes carcinogenesis. Though in vitro studies have shown that As induces senescence, population based
studies are lacking. We investigated the arsenic-induced senescence, telomere length alteration and its contribution
towards development of As-induced skin cancer. The study participants included 60 each of As-exposed individuals with
skin lesion (WSL), without skin lesions (WOSL) and 60 unexposed controls. Exposure assessment of drinking water and urine
was done. SA b-gal activity, ELISA, and quantification of senescence proteins, alternative lengthening of telomere (ALT)
associated proteins and telomerase activity were performed. Relative telomere length (RTL) was determined by qPCR. A
significantly higher number of senescent cells, over-expression of p53 and p21 were observed in the As-exposed individuals
when compared to unexposed. SASP markers, MMP-1/MMP-3 were significantly higher in the WSL but not IL-6/IL-8. A
significant increase of RTL was observed in the WSL group, which was telomerase-independent but exhibited an overexpression
of ALT associated proteins TRF-1 and TRF-2 with higher increase in TRF-2. An increased risk for developing Asinduced
skin lesions was found for individuals having RTL greater than 0.827 (odds ratio, 13.75; 95% CI: 5.66–33.41;
P<0.0001). Arsenic induces senescence in vivo, but the SASP markers are not strictly over-expressed in the As-induced skin
lesion group, whereas telomerase-independent elongation of telomere length might be useful for predicting the risk of
development of As-induced skin lesion
Correlation of Vertical Velocity of Spermatozoa with Fertility Potential and Evaluation of Physiological Significance of Sperm Motility Regulatory Factors
No full textReproduction is one of the fundamental characteristics of living organisms. It involves the transmission of genetic material from one generation to the next, ensuring that the species survives over long periods of time. The study on
reproduction was started during the sixteenth century, and during subsequent centuries intense researches have explored many hidden areas of this field. However
there are many unknown regions which are yet to be revealed.
Anatomically male reproductive system consists of two testicles and a network of excretory ducts (epididymis, vas deferens and ejaculatory ducts), accessory glands (seminal vesicles, the prostate gland and the bulbourethral gland)
and the penis. Testicular spermatozoa acquire fertility only after one or two weeks of transit through the epididymis. At the end of this several meters long epididymal tubule, the male gamete is able to move, capacitate, migrate through the female tract,
bind to the egg membrane and finally fuse to the oocyte to obtain a viable embryo. All these sperm properties are acquired after sequential modifications occurring either at
the level of the spermatozoon or in the epididymal surroundings. Considerable research efforts ongoing in various laboratories are aimed at elucidating the events
accompanying sperm maturation and the role of the epididymis in creating an ideal fluid environment for this process to take place
Therapeutic and immunomodulatory activities of short-course treatment of murine visceral leishmaniasis with KALSOME™10, a new liposomal amphotericin B
Get PDFVisceral leishmaniasis (VL), a potentially fatal disease, is most prevalent in the Indian subcontinent,
East Africa and South America. Since the conventional antileishmanial drugs have many limitations we evaluated a
new ergosterol rich liposomal amphotericin B formulation, KALSOME™10 for its leishmanicidal efficacy, tolerability
and immunomodulatory activity. Normal healthy mice were treated with 3.5 mg/kg single and 7.5 mg/kg single and double doses ofKALSOME™10. Liver and kidney function tests were performed fourteen days after treatment. Next, normal mice were infected with Leishmania donovani amastigotes. Two months post infection they were treated with the above
mentioned doses of KALSOME™10 and sacrificed one month after treatment for estimation of parasite burden in
the liver and spleen by Limiting Dilution Assay. Leishmanial antigen stimulated splenocyte culture supernatants were collected for cytokine detection through ELISA. Flow cytometric studies were performed on normal animals treated with KALSOME™10, Amphotericin B (AmB) and AmBiosome to compare their immunomodulatory activities.
The drug was found to induce no hepato- or nephrotoxicities at the studied doses. Moreover, at all doses,
it led to significant reduction in parasite burden in two month infected BALB/c mice, with 7.5 mg/kg double dose
resulting in almost complete clearance of parasites from both liver and spleen. Interestingly, the drug at 7.5 mg/kg
double dose could almost completely inhibit the secretion of disease promoting cytokines, IL-10 and TGFβ, and
significantly elevate the levels of IFNγ and IL-12, cytokines required for control of the disease. Mice treated with KALSOME™10 showed elevated levels of IFNγ and suppressed IL-10 secretion from both CD4+ and CD8+ subsets
of T cells, as well as from culture supernatants of splenocytes, compared to that of normal, AmB and AmBisome
treated animal Treatment of infected mice with 7.5 mg/kg double dose of KALSOME™10 was safe and effective in
clearing the parasites from the sites of infection. The drug maintains the inherent immunomodulatory activities of
AmB by effectively suppressing disease promoting cytokines IL-10 and TGFβ, thereby boosting IL-12 and IFNγ levels.
This emphasizes KALSOME™10 as a promising drug alternative for lifelong protection from VL
Therapy with radio-attenuated vaccine in experimental murine visceral leishmaniasis showed enhanced T cell and inducible nitric oxide synthase levels, suppressed tumor growth factor-beta production with higher expression of some signaling molecules
No full textBackground: Visceral leishmaniasis (VL) or Kala-Azar (KA) is one of the most deadly formsof disease among all neglected tropical diseases. There are no satisfactory drugs or vac-cine candidates available for this dreaded disease. Our previous studies showed promisingtherapeutic and prophylactic efficacy of the live, radio-attenuated parasites through intra-muscular (I.M.) and intraperitoneal (I.P.) route in BALB/c mice model.Methods: The T-cell proliferation level, the mRNA expression level of inducible nitric oxidesynthase (iNOS) and tumor growth factor-beta (TGF-�) genes and finally the phosphorylationlevels of phosphoinositide dependent kinase 1 (PDK1), phosphoinositide 3 kinase (PI3K) andp38 mitogen activated protein kinase (p38MAPK) molecules were checked in BALB/c micemodel immunized with radio-attenuated Leishmania donovani parasites through I.M. route.Results: Higher T-cell proliferation, increased iNOS level, and suppressed TGF-� level werefound in treated infected animal groups (100 and 150 Gy) in relation to untreated infectedanimals. Likewise, phosphorylation levels of PDK1, PI3K and p38MAPK of these two groupswere increased when compared to untreated infected controls.Conclusion: The clearance of the parasites from treated infected groups of animals maybe mediated by the restoration of T-cell due to therapy with radio-attenuated L. donovaniparasites. The killing of parasites was mediated by increase in nitric oxide release throughPDK1, PI3K and p38MAPK signaling pathways. A lower TGF-� expression has augmentedthe restored Th1 ambience in the 100 and 150 Gy treated animal groups proving further theefficacy of the candidate vaccin
A survey on prediction of specificity-determining sites in proteins
No full textSpecificity-determining sites (SDS) are the key positions of a protein family that show a specific conservation of
amino acids, related to the subfamily members of that family. SDS play crucial role in developing functional variation within the protein family during the course of evolution.Thus, it is important to identify SDS to understand the evolutionary process of diversification of biological functions within a protein family. A wide range of computational tools have been designed to detect such SDS. In this review, we intend to examine the concept of SDS in more detailsalong with the advancements and drawbacks of different computational approaches designed towards successful prediction of SDS. Further, we discussed the algorithms behind the computational approaches developed till dateand provide an exhaustive comparison of performance of each method.We also introduce a new ensemble approach, SubSite as another tool to predict SDS through a user-friendly webserver available at
Subtle Change in the Charge Distribution of Surface Residues May Affect the Secondary Functions of Cytochrome c
No full textAlthough the primary function of cytochrome c (cyt c) is electron
transfer, the protein caries out an additional secondary
function involving its interaction with membrane cardiolipin
(CDL), its peroxidase activity, and the initiation of apoptosis.
Whereas the primary function of cyt c is essentially conserved,
its secondary function varies depending on the source of the
protein. We report here a detailed experimental and computational
study, which aims to understand, at the molecular level,
the difference in the secondary functions of cyt c obtained from
horse heart (mammalian) and Saccharomyces cerevisiae (yeast).
The conformational landscape of cyt c has been found to be heterogeneous,
consisting of an equilibrium between the compact
and extended conformers as well as the oligomeric species.
Because the determination of relative populations of these conformers
is difficult to obtain by ensemble measurements, we
used fluorescence correlation spectroscopy (FCS), a method
that offers single-molecule resolution. The population of different
species is found to depend on multiple factors, including the
protein source, the presence of CDL and urea, and their concentrations.
The complex interplay between the conformational
distribution and oligomerization plays a crucial role in the variation
of the pre-apoptotic regulation of cyt c observed from different
sources. Finally, computational studies reveal that the
variation in the charge distribution at the surface and the charge
reversal sites may be the key determinant of the conformational
stability of cyt c