2058 research outputs found
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In Vitro Initiated Sperm Forward Motility in Caput Spermatozoa: Weak and Transient
No full textTesticular spermatozoa during journey through epididymis acquire forward
motility, which is essential for fertility. To understand the biochemistry of
sperm motility initiation, various initiation media have been developed that
permitted high level of motility induction (55–60%) in the immature caputspermatozoa
in presence of activating principles: theophylline, bicarbonate and
epididymal plasma (EP) when analysed microscopically. Here, we show for the
first time using caprine model that stability and quality of in vitro-induced
motility in the caput spermatozoa is insignificant in contrast to naturally
induced motility in mature cauda spermatozoa. In vitro-induced motility of the
immature spermatozoa was lost completely upon the removal of these activators
by centrifugation. Selective withdrawal of either EP or HCO3 by dilution
retains 50–60% of the in vitro-induced motility. Spectrophotometric analysis
revealed that in vitro-induced vertical motility in immature spermatozoa is too
little when compared to mature spermatozoa. In in vitro-initiated caput spermatozoa,
cyclic adenosine monophosphate level becomes doubled but lesser
than cauda spermatozoa. This revelation concludes that scientific knowledge
generated over the years on the basis of in vitro initiation method is insignificant
and needs improvisation to delineate biochemical regulation of sperm
motility which in turn has remarkable potential in wide biological fields,
especially in infertility treatment
Subtype-Specific Alterations of the Wnt Signaling Pathway in Breast Cancer: Clinical and Prognostic Significance
No full textThe aim of the study is to understand the importance of the
Wnt ⁄ b-catenin pathway in the development of breast cancer (BC)
and its association with different clinicopathological parameters.
Alterations (deletion ⁄ methylation ⁄ expression) of some Wnt ⁄
b-catenin pathway antagonists like APC, SFRP1 ⁄ 2, CDH1 and activator
b-catenin (CTNNB1) were analyzed in primary BC in Indian
patients. High frequencies (65–70%) of overall alterations (deletion
⁄ methylation) of the antagonists were seen in the BC samples.
Also, 99% (156 ⁄ 158) of the samples showed alterations in any one
of the genes, indicating the importance of this pathway in the
development of this tumor. Co-alterations of these genes were
observed in 30% of samples, with significantly high alterations in
late-onset (37%) and estrogen receptor (ER)) ⁄ progesterone receptor
(PR)) (37%) BC compared with early onset (21%) and ER ⁄ PR+
(18%) BC samples, respectively. Significantly high (P-value =
0.001–0.02) alterations of APC and CDH1 genes were seen in
ER) ⁄ PR) BC compared with ER ⁄ PR+ BC. Immunohistochemical
analysis showed reduced expression of the Wnt antagonists in BC
concordant with their molecular alterations. Nuclear localization
of b-catenin showed significant association with alterations in the
antagonists and was also significantly high in the ER) ⁄ PR) BC
samples. Alterations of SFRP2 coupled with a late clinical stage
and low ⁄ nulliparity predicted the worst prognosis in BC patients.
Therefore, the present study suggests that cumulative alterations
in more than one Wnt antagonist along with increased nuclear
accumulation of b-catenin play an important role in the development
of BC and have significant clinical as well as prognostic
importance
Induction of Cr(VI) Reduction Activity in an Anoxybacillus Strain under Heat Stress: a Biochemical and Proteomic Study
No full textA bacterial strain, designated as TSB-6, was isolated from the sediments of a
Tantloi (India) hot spring at 65 °C. The strain showed 98% 16S rRNA gene
sequence similarity with Anoxybacillus kualawohkensis strain KW12 and was
found to grow optimally at 37 °C. However, growing cells, cell suspensions,
and cell-free extracts from 65 °C cultures showed higher Cr(VI) reduction
activities when assayed at either 37 or 65 °C than those obtained from 37 °C
cultures. On fractionation of extracts from cells grown at 65 °C, the chromate
reductase activity assayed at 65 °C was found mostly in the soluble fraction.
When log-phase cells growing at 37 °C were shifted to 65 °C, the stressed cells
produced larger quantities of reactive oxygen species. Consequently, growth of
the cells was retarded, but specific Cr(VI) reduction activity increased. 2D gel
electrophoresis followed by MALDI-TOF MS/MS identified the proteins whose
expression level changed as a result of heat stress. The upregulated set included
proteins involved in cellular metabolism of sugar, nucleotide, amino acids,
lipids and vitamins, oxidoreductase activity, and protein folding. The downregulated
proteins are also involved in cellular metabolism, DNA binding, and
environmental signal processing
Discovery of Safe and Orally Effective 4-Aminoquinaldine Analogues as Apoptotic Inducers with Activity against Experimental Visceral Leishmaniasis
No full textNovel antileishmanials are urgently required to overcome emergence of drug resistance, cytotoxic effects, and difficulties in oral
delivery. Toward this, we investigated a series of novel 4-aminoquinaldine derivatives, a new class of molecules, as potential antileishmanials.
4-Aminoquinaldine derivatives presented inhibitory effects on L. donovani promastigotes and amastigotes (50%
inhibitory concentration range, 0.94 to 127�M). Of these, PP-9 and PP-10 were the most effective in vitro and demonstrated
strong efficacies in vivo through the intraperitoneal route. They were also found to be effective against both sodium antimony
gluconate-sensitive and -resistant Leishmania donovani strains in BALB/c mice when treated orally, resulting in more than 95%
protection. Investigation of their mode of action revealed that killing by PP-10 involved moderate inhibition of dihydrofolate
reductase and elicitation of the apoptotic cascade. Our studies implicate that PP-10 augments reactive oxygen species generation,
evidenced from decreased glutathione levels and increased lipid peroxidation. Subsequent disruption of Leishmania promastigote
mitochondrial membrane potential and activation of cytosolic proteases initiated the apoptotic pathway, resulting in DNA
fragmentation and parasite death. Our results demonstrate that PP-9 and PP-10 are promising lead compounds with the potential
for treating visceral leishmaniasis (VL) through the oral route
Cholinesterase Inhibition Activity of Marsilea Quadrifolia Linn. an Edible Leafy Vegetable from West Bengal, India
No full textMaesilea quadrifolia Linn. (Marsileaceae) is a leafy vegetable well known in India.
The current study aims to explore the phytochemical profile of M. quadrifolia and
investigate its anti-cholinesterase potential. The methanol extract of the plant was
subjected to qualitative and quantitative phytochemical screening (total alkaloidal
content, saponin content and phenol content) and its anti-cholinesterase
potential was tested by TLC bioautography and other screening methods using
acytylcholinesterase (AChE) and butyrylcholinesterase (BChE). The study
revealed that the extract contains various classes of phytoconstituents including
steroids, saponins, alkaloids and other polyphenols. Total alkaloid, phenolic and
saponin contents were found to be 19.3 mgg�1 and 158.5�1.02mg g�1 as gallic
acid equivalents and 2.63 mgg�1 of the extract, respectively. The TLC
bioautography method exhibited the inhibition of both enzymes. In a microtiter
plate assay, the IC50 values of the extract for AChE and BChE were found to be
51.89�0.24 mgmL�1 and 109.43�2.82 mgmL�1, respectively. These findings
suggest that M. quadrifolia is a potential lead as an AChE and BChE inhibitor,
which may be useful in the management of Alzheimer’s disease
Carbohydrate Nitrone and Nitrile Oxide Cycloaddition Approach to Chiral Sulfur Heterocycles and Nucleosides
No full textS-Alkenyl and -alkynyl carbohydrate derivatives were prepared from 1,2 : 5,6-O-diisopropylidene-a-
D-allofuranose. Nitrones and nitrile oxides generated from these derivatives led to the formation of 6,
7, and 11-membered chiral sulfur heterocycles fused to isoxazolidine, isoxazoline and isoxazole rings.
Some of these sulfur heterocycles were converted to nucleosides. The 11-memebered sulfur compound
was found to gelate hydrocarbon solvents
Palladium-Catalyzed 8-Exo Trig Intramolecular Heck Reaction Under Microwave Irradiation in the Presence of Basic Alumina
No full textThe Heck cross-coupling reaction has been employed for efficient conversion of
quinolines to benzoxocinoquinoline through a microwave-assisted palladium-catalyzed
intramolecular cyclization in the presence of basic alumin
Deglycosylation Effect of the Mammalian Sperm Maturation Antigen (SMA2) on Serological Reaction and Acrosome Reaction
No full textSpermatozoal membrane proteins are considered to possess several immunological unique characteristics as the cell is formed behind the blood-testes barriers. Major goat sperm maturation antigen (SMA2) contains one hexosamine along with mannose, galactose and glucose. In the present study, effects of deglycosylation of SMA2 antigen on immunoreactivity and the serological activity was investigated. SMA2 glycoantigen showed positive
immunoreactivity after treatment with sodium borohydride (NaBH4) and moreover this generated a 44 kDa protein band which was negative for periodic acid Schiff reagent. Trifluoromethanesulfonic acid (TFMS) caused aggregation and restricted the free mobility of the treated antigen on SDS-PAGE and the protein band generated by TFMS treatment also showed positive immuno-reactivity. The results supported the views that the protein portion retains its immuno-reactivity even after oxidation of the vicinal hydroxyl group of saccharide component of SMA2 antigen. These data suggest that immunodominent epitopes exist on the core protein by which the SMA2 antigen retains its immuno-reactivity
even after disruption of the saccharide portion. Additional experiments demonstrate that protein epitopes have a role in capacitation and the acrosome reaction (AR) in presence of antibody which is raised against this protein part of SMA2 using the negative staining of FITC-PSA (fluorescein isothiocyanate-labeled Pisum sativum agglutinin) probe. Altogether these findings indicate that the protein portion of SMA2 might fulfill the serological activity of the antigen as well as the protein epitope affects the acrosome reaction. In view of this property, we propose that the protein portion of SMA2 antigen might be considered as a potential antigenic target for an immune response
Eggshell Membrane: a Natural Biotemplate to Synthesize Fluorescent Gold Nanoparticles
No full textIn this article we report a simple, environmentally friendly, and naturally available protein based
biotemplate, viz. the chicken eggshell membrane, truly one of nature’s gifts, for preparing highly
fluorescent gold nanoparticles in solution at ambient conditions in a single step. We propose this as a
simple green method to prepare gold nanoparticles both in solution and on the membrane for various
applications. A stable colloidal solution of fluorescent Au nanoparticles has been formed in situ
during the reduction. The gold nanoparticles, consisting of sizes below 20 nm, were highly fluorescent
and exhibited intense blue emission around 437 ¡ 5 nm. Red emission around 630 ¡ 5 nm was also
observed for the solution. The novelty of this technique lies in the unique properties of this
membrane, such as high resistance to pH, safety in handling, and abundant availability in nature. The
most important feature of this method is the easy abundance of the source material, which enables
cost-effective preparation of gold nanoparticles. In addition to preparing nanoparticles of metals for
various applications, this could be used as a very simple method to recover precious metals from
chemical and industrial wast
Synthesis of Polynuclear Azaheterocycles Based on Indoles and Fused Quinolines
No full textThe thesis embodies the results of studies on “Synthesis of polynuclear azaheterocycles based on indoles and fused quinolines”. Important pharmaceuticals often possess aza-heterocyclic moieties as their building blocks. The extensive use of aza-heterocyclic compounds in the pharmaceutical industry is perhaps attributable to
the availability of ample range of reactions that facilitate subtle structural modifications in aza-heterocyclic compounds. Chemical and biological research has
now presented a great challenge to synthesize and optimise highly efficient and costeffective ecofriendly synthetic routes to some structuraily unique and biologically
active substances.Since indole, fused quinoline and its derivatives possess various biological activities
and these moieties are found in many bioactive natural products, so, development of new methodologies for the synthesis of indole and fused quinoline derivatives, which
will yield subsets of aza-heterocycles having the potentiality to serve as templates for new biologically active molecules, is of great importance