In silico exploration of hypothetical proteins in Neisseria gonorrhoeae for identification of therapeutic targets

Neisseria gonorrhoeae, a World Health Organization (WHO) declared superbug and the second-most frequent cause of bacterial sexually transmitted infections worldwide is responsible for gonorrhea. Hypothetical proteins are gene products that are predicted to be encoded by a particular gene based on the DNA sequence, but their specific functions and characteristics have not been experimentally determined or verified. In the context of this research, annotating hypothetical proteins is crucial for identifying their potential as therapeutic targets. Without proper annotation, these proteins would remain vague, hindering efforts to understand their roles in disease. The methodology used aims to bridge this gap by employing algorithm-based tools and software to annotate hypothetical proteins and assess their suitability as therapeutic targets based on factors such as essentiality, virulence, subcellular localization, and druggability. Out of 716 N. gonorrhoeae hypothetical proteins reported in UniProt, assessment of crucial pathogenic factors, including essentiality, virulence, subcellular localization, and druggability, effectively filtered and prioritized the hypothetical proteins for further therapeutic exploration and lead to 5 proteins being chosen as targets. The molecular docking studies conducted identified 10 hits targeting the five targets. Conclusively, this study aided in identification of targets and hit compounds for therapeutic targeting of gonorrhea disease.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s40203-023-00186-w.

Biodegradable nanocarrier of gemcitabine and tocopherol succinate synergistically ameliorates anti-proliferative response in MIA PaCa-2 cells

Gemcitabine (GEM) is an important chemotherapeutic agent used alone or in combination with other anticancer agents for the treatment of various solid tumors. In this study, the potential of a dietary supplement, α-tocopherol succinate (TOS) was investigated in combination with GEM by utilizing human serum albumin-based nanoparticles (HSA NPs). The developed nanoparticles were characterized using DLS, SEM and FTIR and evaluated in a panel of cell lines to inspect cytotoxic efficacy. The ratio metric selected combination of the NPs was further investigated in human pancreatic cancer cell line (MIA PaCa-2 cells) to assess the cellular death mechanism via a myriad of biochemical and bio-analytical assays including nuclear morphometric analysis by DAPI staining, ROS generation, MMP loss, intracellular calcium release, in vitro clonogenic assay, cell migration assay, cell cycle analysis, immunocytochemical staining followed by western blotting, Annexin V-FITC and cellular uptake studies. The desolvation-crosslinking method was used to prepare the NPs. The average size of TOS-HSA NPs and GEM-HSA NPs was found to be 189.47 ± 5 nm and 143.42 ± 7.4 nm, respectively. In combination, the developed nanoparticles exhibited synergism by enhancing cytotoxicity in a fixed molar ratio. The selected combination also significantly triggered ROS generation and mitochondrial destabilization, alleviated cell migration potential and clonogenic cell survival in MIA PaCa-2 cells. Further, cell cycle analysis, Annexin-V FITC assay and caspase-3 activation, up regulation of Bax and down regulation of Bcl-2 protein confirmed the occurrence of apoptotic event coupled with the G0/G1 phase arrest. Nanocarriers based this combination also offered approximately 14-folds dose reduction of GEM. Overall, the combined administration of TOS-HSA NPs and GEM-HSA NPs showed synergistic cytotoxicity accompanied with dose reduction of the gemcitabine. These encouraging findings could have implication in designing micronutrient based-combination therapy with gemcitabine and demands further investigation.

Multifunctional GQDs for receptor targeting, drug delivery, and bioimaging in pancreatic cancer

Pancreatic cancer is a devastating disease with a low survival rate and limited treatment options. Graphene quantum dots (GQDs) have recently become popular as a promising platform for cancer diagnosis and treatment due to their exceptional physicochemical properties, such as biocompatibility, stability, and fluorescence. This review discusses the potential of multifunctional GQDs as a platform for receptor targeting, drug delivery, and bioimaging in pancreatic cancer. The current studies emphasized the ability of GQDs to selectively target pancreatic cancer cells by overexpressing binding receptors on the cell surface. Additionally, this review discussed the uses of GQDs as drug delivery vehicles for the controlled and targeted release of therapeutics for pancreatic cancer cells. Finally, the potential of GQDs as imaging agents for pancreatic cancer detection and monitoring has been discussed. Overall, multifunctional GQDs showed great promise as a versatile platform for the diagnosis and treatment of pancreatic cancer. Further investigation of multifunctional GQDs in terms of their potential and optimization in the context of pancreatic cancer therapy is needed.

Repositioning the existing drugs for neuroinflammation: a fusion of computational approach and biological validation to counter the Parkinson's disease progression

Parkinson's disease is caused by the deficiency of striatal dopamine and the accumulation of aggregated α-synuclein in the substantia nigra pars compacta (SNpc). Neuroinflammation associated with oxidative stress is a key factor contributing to the death of dopaminergic neurons in SNpc and advancement of Parkinson's disease. Two molecular targets, i.e., nuclear factor kappa-light-chain-enhancer (NF-kB) and α-synuclein play a substantial role in neuroinflammation progression. Therefore, the compounds targeting these neuroinflammatory targets hold a great potential to combat Parkinson's disease. Thereby, in this study, molecular docking and Connectivity Map (CMap) based gene expression profiling was utilized to reposition the approved drugs as neuroprotective agents for Parkinson's disease. With in silico screening, two drugs namely theophylline and propylthiouracil were selected for anti-neuroinflammatory activity evaluation in in vivo models of chronic neuroinflammation. The neuroinflammatory effect of the identified compounds was confirmed by quantifying the expression of three important neuroinflammatory mediators, i.e. IL-6, TNF-alpha, and IL-1 beta on brain tissue using ELISA assay. The ELISA experiment demonstrated that both compounds significantly decreased the expression of neuroinflammatory mediators, highlighting the compounds' potential in neuroinflammation management. Furthermore, the drug and disease interaction network of the two identified drugs and diseases (neuroinflammation and Parkinson's disease) suggested that the two drugs might interact with various targets namely adenosine receptors, Poly [ADP-ribose] polymerase-1, myeloperoxidase (MPO) and thyroid peroxidase through multiple pathways associated with neuroinflammation and Parkinson's disease. Computational studies suggest that a particular drug may be effective in managing Parkinson's disease associated with neuroinflammation. However, further research is needed to confirm this in biological experiments.

Revisiting the therapeutic potential of gingerols against different pharmacological activities

The rhizomes of ginger have been in use in many forms of traditional and alternative medicines. Besides being employed as condiment and flavoring agent, it is used in the treatment of nausea, osteoarthritis, muscle pain, menstrual pain, chronic indigestion, Alzheimer's disease, and cancer. Ginger rhizome contains volatile oils, phenolic compounds and resins, and characterization studies showed that [6]-gingerol, [6]-shogaol, and [6]-paradol are reported to be the pharmacologically active components. Gingerol is a major chemical constituent found as volatile oil in the rhizomes of ginger. It has several medicinal benefits and used for the treatment of rheumatoid arthritis, nausea, cancer, and diabetes. Many studies have been carried out in various parts of the world to isolate and standardize gingerol for their use as a complementary medicine. The present review summarizes wide range of research studies on gingerol and its pharmacological roles in various metabolic diseases.

Metal-based nanomaterials and nanocomposites as promising frontier in cancer chemotherapy

Cancer is a disease associated with complex pathology and one of the most prevalent and leading reasons for mortality in the world. Current chemotherapy has challenges with cytotoxicity, selectivity, multidrug resistance, and the formation of stemlike cells. Nanomaterials (NMs) have unique properties that make them useful for various diagnostic and therapeutic purposes in cancer research. NMs can be engineered to target cancer cells for early detection and can deliver drugs directly to cancer cells, reducing side effects and improving treatment efficacy. Several of NMs can also be used for photothermal therapy to destroy cancer cells or enhance immune response to cancer by delivering immune-stimulating molecules to immune cells or modulating the tumor microenvironment. NMs are being modified to overcome issues, such as toxicity, lack of selectivity, increase drug capacity, and bioavailability, for a wide spectrum of cancer therapies. To improve targeted drug delivery using nano-carriers, noteworthy research is required. Several metal-based NMs have been studied with the expectation of finding a cure for cancer treatment. In this review, the current development and the potential of plant and metal-based NMs with their effects on size and shape have been discussed along with their more effective usage in cancer diagnosis and treatment.

Simulated physiological oocyte maturation (SPOM) improves developmental competence of in vitro produced goat embryos

The effect of simulated physiological oocyte maturation on the developmental competence, reactive oxygen species production and apoptosis rate of in vitro produced goat embryos were studied in the present experiment. Oocytes and spermatozoa were recovered from ovaries and epididymis, respectively, procured from a local small animal abattoir. The oocytes aspirated from the ovaries were allocated into two groups, control (subjected to routine in vitro maturation, fertilization and culture) and simulated physiological oocyte maturation (SPOM) group (subjected to prematuration, followed by routine in vitro maturation, fertilization and culture). The SPOM group showed a significantly (p < 0.05) higher maturation and blastocyst rates (90.60 ± 0.46% and 29.09 ± 2.59%, respectively) as compared to the control group (85.29 ± 0.98% and 24.09 ± 1.08%). The intensity of reactive oxygen species of the embryos in the control group (14.98 ± 0.83 pixels/embryo) was significantly (p < 0.05) higher than the SPOM group (9.60 ± 0.76 pixels/embryo). The apoptosis rate was also significantly (p < 0.05) higher in the embryos of the control group (9.18 ± 1.07%) as compared to the SPOM group (5.71 ± 0.90%). In conclusion, the simulated physiological oocyte maturation system significantly increases the developmental competence of the oocytes and decreases the intensity of reactive oxygen species and embryonic apoptosis in abattoir derived goat embryos.

Prognostic Value of Squamous Cell Carcinoma Antigen in Patients with Uterine Cervical Carcinoma

Squamous cell carcinoma antigen (SCC Ag) was estimated in 30 controls, in 16 patients with benign lesions of the uterine cervix, and in 51 patients with uterine cervical carcinoma. The rate of positivity of the antigen among the cancer patients was 87% (N = 49). SCC Ag estimations were of no diagnostic value, since 37% of patients with bening lesions had elevated levels compared to controls. SCC Ag was highly correlated to histologic subtype. The highest values were obtained in keratinizing tumors, followed by large cell nonkeratinizing and small cell nonkeratinizing types. Moreover, elevation of SCC Ag was statistically significant (p < 0.001) among all the three histologic subtypes compared to controls. However, SCC Ag levels were not consistently correlated to the stage of the disease. Patients with pretherapeutic SCC Ag levels above 30 ng/ml had a faster recurrence rate and shorter survival than those who exhibited antigen values below 2.0 ng/ml. From our results, it is suggested that SCC Ag has limited use as a parameter for early diagnosis of cervical carcinoma, but it seems to reflect advancement of the disease. These findings indicate that SCC Ag elevation may prove to be a valuable marker in predicting subclinical disease.

Comparison of Prolactin, CA 15–3 and TPA in Breast Carcinomas

Circulating prolactin, CA 15–3 and TPA were assayed pre-therapeutically and sequentially thereafter from 68 breast cancer patients attending the Gujarat Cancer and Research Institute, Ahmedabad — a regional cancer institute in Western India. The three marker values were correlated with the stage, histologic grade and disease status. At least one of the markers was elevated in 82% of patients. CA 15–3 and TPA levels were elevated with the advancement of stage. Prolactin levels were high in poorly differentiated tumors of pre-menopausal patients. The disease status was effectively reflected by the levels of prolactin and CA 15–3. TPA showed high false positivity so was of no use as an indicator of disease status. Recurrence could be predicted early, with a lead time of 3–6 months using prolactin and CA 15–3.

In silico kinetics of alkaline hydrolysis of 1,3,5-trinitro-1,3,5-triazinane (RDX): M06-2X investigation

Alkaline hydrolysis of RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine), as one of the most promising methods for nitrocompound remediation, was investigated computationally at the PCM(Pauling)/M06-2X/6-311++G(d,p) level of theory. Computational simulation shows that RDX hydrolysis is a highly exothermic multistep process involving initial deprotonation and nitrite elimination, cycle cleavage, further transformation of cycle-opened intermediates to end products caused by a series of C-N bond ruptures, hydroxide attachments, and proton transfers. Computationally predicted products of RDX hydrolysis such as nitrite, nitrous oxide, formaldehyde, formate, and ammonia correspond to experimentally observed ones. Accounting of specific hydration of hydroxide is critical to create an accurate kinetic model for alkaline hydrolysis. Simulated kinetics of the hydrolysis are in good agreement with available experimental data. A period of one month is necessary for 99% RDX decomposition at pH 10. Computations predict significant increases of the reaction rate of hydrolysis at pH 11, pH 12, and pH 13.

Emergence of dengue in tribal villages of Mandla district, Madhya Pradesh, India

Background & objectives:

Dengue (DEN) is a rapidly spreading arboviral disease transmitted by Aedes mosquitoes. Although it is endemic in India, dengue virus (DENV) infection has not been reported from tribal areas of Madhya Pradesh. Investigations were conducted to establish the aetiology of sudden upsurge of cases with febrile illness in June 2013 from tribal villages of Mandla district of Madhya Pradesh, India.

Methods:

The rapid response team of the National Institute for Research in Tribal Health, Jabalpur, conducted clinical investigations and field surveys to collect the samples from suspected cases. Samples were tested using molecular and serological tools. Collected mosquitoes were identified and tested for the presence of virus using semi nested reverse transcriptase-polymerase chain reaction (nRT-PCR). The sequences were analysed to identify serotype and genotype of the virus.

Results:

Of the 648 samples collected from 18 villages of Mandla, 321 (49.53%) were found to be positive for dengue. The nRT-PCR and sequencing confirmed the aetiology as dengue virus type 2. Eighteen per cent of patients needed hospitalization and five deaths were attributed to dengue. The virus was also detected from Aedes aegypti mosquito, which was incriminated as a vector. Phylogenetic analysis revealed that the dengue virus 2 detected belonged to cosmopolitan genotype of the virus.

Interpretation & conclusions:

Dengue virus serotype 2 was detected as the aetiological agent in the outbreak in tribal villages of Mandla district of Madhya Pradesh. Conducive man-made environment favouring mosquitogenic conditions and seeding of virus could be the probable reasons for this outbreak. Urgent attention is needed to control this new threat to tribal population, which is already overburdened with other vector borne diseases.

Constructed wetland as an ecotechnological tool for pollution treatment for conservation of Ganga river

With aim to develop an efficient and ecofriendly approach for on-site treatment of sewage, a sub-surface flow constructed wetland (CW) has been developed by raising potential aquatic macrophytes; Typha latifolia, Phragmites australis, Colocasia esculenta, Polygonum hydropiper, Alternanthera sessilis and Pistia stratoites in gravel as medium. Sewage treatment potential of CW was evaluated by varying retention time at three different stages of plant growth and stabilization. After 6 months, monitoring of fully established CW indicated reduction of 90%, 65%, 78%, 84%, 76% and 86% of BOD, TSS, TDS, NO3-N, PO4-P and NH4-N, respectively in comparison to inlet after 36 h of retention time. Sewage treatment through CW also resulted in reduction of heavy metal contents. Thus, CW proved an effective method for treatment of wastewater and may be developed along river Ganga stretch as an alternative technology. Treated water may be drained into river to check further deterioration of Ganga water quality.

Responses of cyanobacterium Anabaena doliolum during nickel stress

Growth and biochemical responses of heterocystous nitrogen fixing cyanobacteria Anabaena doliolum were studied upon exposure to various concentrations of nickel (0.1 to 100 microM) for duration of up to 4 days, in view of its tolerance. The growth of the cyanobacterium was increased in terms of cell density (O.D), heterocyst frequency chlorophyll-a, carotenoid and c-phycocynin up to moderate exposure (10 microM for 96 hr of Ni treatment). Protein and total non protein thiol were measured as stress responsive metabolites and frequency of heterocyst and spores were observed in responses to Ni. The present study demonstrated that the tested cyanobacterium exhibited dose specific responses of metal towards studied different morphological, physiological and biochemical parameters.

Response of antioxidant enzymes in coontail (Ceratophyllum demersum L.) plants under cadmium stress

Cadmium (Cd) contamination of aquatic systems is of major concern since it is a nonessential element and hampers plant growth upon accumulation. The aim of this study was to investigate the Cd accumulation behavior of coontail plant, Ceratophyllum demersum L., toxicity induced and response of the antioxidant system. Plants were exposed to various concentrations of Cd (0-10 microM) for a period of 1-7 days. Accumulation of Cd was found to be a concentration duration dependent phenomenon. The maximum accumulation of Cd, 1293 microg g(-1) dw, was observed after 7 days at 10 microM. Plants showed significant stimulation of the activities of various antioxidant enzymes viz., superoxide dismutase (EC 1.15.1.1), ascorbate peroxidase (EC 1.11.1.11), guaiacol peroxidase (EC 1.11.1.7), catalase (EC 1.11.1.6), and glutathione reductase (EC 1.6.4.2) and tolerated toxicity of Cd up to moderate concentration of 5 microM. At 10 microM exposure, enzyme activities declined and plants experienced toxicity, which was evident by the significant decrease in the photosynthetic pigments and by increase in the levels of H(2)O(2), lipid peroxidation and ion leakage. In conclusion, modulation of antioxidant system in a coordinated manner in response to Cd accumulation appears to help plants tolerate toxicity of Cd up to 5 microM.

Role of blue green algae biofertilizer in ameliorating the nitrogen demand and fly-ash stress to the growth and yield of rice (Oryza sativa L.) plants

Rice is a major food crop throughout the world; however, accumulation of toxic metals and metalloids in grains in contaminated environments is a matter of growing concern. Field experiments were conducted to analyze the growth performance, elemental composition (Fe, Si, Zn, Mn, Cu, Ni, Cd and As) and yield of the rice plants (Oryza sativa L. cv. Saryu-52) grown under different doses of fly-ash (FA; applied @ 10 and 100 tha(-1) denoted as FA(10) and FA(100), respectively) mixed with garden soil (GS) in combination with nitrogen fertilizer (NF; applied @ 90 and 120 kg ha(-1) denoted as NF(90) and NF(120), respectively) and blue green algae biofertilizer (BGA; applied @ 12.5 kg ha(-1) denoted as BGA(12.5)). Significant enhancement of growth was observed in the plants growing on amended soils as compared to GS and best response was obtained in amendment of FA(10)+NF(90)+BGA(12.5). Accumulation of Si, Fe, Zn and Mn was higher than Cu, Cd, Ni and As. Arsenic accumulation was detected only in FA(100) and its amendments. Inoculation of BGA(12.5) caused slight reduction in Cd, Ni and As content of plants as compared to NF(120) amendment. The high levels of stress inducible non-protein thiols (NP-SH) and cysteine in FA(100) were decreased by application of NF and BGA indicating stress amelioration. Study suggests integrated use of FA, BGA and NF for improved growth, yield and mineral composition of the rice plants besides reducing the high demand of nitrogen fertilizers.

Vibrational analysis of complexes of urate with IA group metal cations (Li+, Na+ and K+)

Vibrational frequency analysis was performed for the complexes of alkali metal cations (Li+, Na+ and K+) with urate in the gas phase. The geometries of all possible metal cation-urate complexes were optimized at the B3LYP/6-311++G(d,p) level. The most stable complex corresponding to the each cation was used for the vibrational frequency analysis including the computation of % potential energy distribution (%PED). For comparison, the vibrational frequency analysis was also performed for the uric acid. The computed results are discussed in terms of the available experimental data. It was revealed that the characteristic stretching vibrational modes corresponding to the metal cation and the interacting nucleophilic sites of urate can be used to identify metals involved in the stone formation in the living system. Changes in different vibrational frequencies of uric acid consequent to the metal cation interactions are discussed.

Electronic Spectra, Excited State Structures and Interactions of Nucleic Acid Bases and Base Assemblies: A Review

A comprehensive review of recent theoretical and experimental advances in the singlet electronic transitions, excited state structures and dynamics of nucleic acid bases (NABs) and base assemblies are presented. It is well known that NABs absorb ultraviolet radiation, but the absorbed energy is efficiently dissipated in the form of ultrafast internal conversion processes believed to occur in the subpicosecond time scale and, therefore, enabling NABs highly photostable. It is not known how much evolutionary role was played in evolving these molecules and the ultimate selection by nature as genetic materials, but it is well accepted that survival-of-fittest prevails. Recently, significant efforts have been continuously paid to understand the mechanism of electronic excitation deactivation, but universally acceptable mechanism is still elusive. However, recent investigations reveal that electronic excited state geometries of DNA bases are usually nonplanar and this structural nonplanarity may facilitate nonradiative deactivation. Investigation of excited state structures is challenging and, therefore, it is not surprising that despite the impressive theoretical and computational advances, this research area is still hampered by the methodological and computational limitations. Further, stacking has significant influence on the emission properties of molecules. The 2-aminopurine, a fluorescent adenine derivative frequently used in studying DNA dynamics, shows significant attenuations in fluorescence quantum yield when incorporated in the DNA. Theoretical and computational bottlenecks limit a thorough theoretical understanding of effect of stacking interactions on the excited state dynamics of NABs. Despite these limitations the investigations of excited state properties are progressing in the right direction and our better understanding of excited state structure and dynamics of NABs and nucleic acids may help to design preventive strategy for radiation induced illness and photostable materials.

Morphology and cultural behavior of Botryococcus protuberans with notes on the genus

The green alga Botryococcus protuberans was isolated from its natural environment and its morphology under different cultural conditions was examined. The alga was characterized by a high starch content and reddish oil drops as the assimilatory products. Photosynthetic pigments, Chl a, Chl b, carotenoids and xanthophylls are present. Modification of environmental conditions in modified Chu-10 medium resulted in optimum growth of the alga. Fatty acid composition revealed palmitic acid being the major component, while lauric acid, myristic acid and stearic acid were found in less quantity.

Growth performance and biochemical responses of three rice (Oryza sativa L.) cultivars grown in fly-ash amended soil

The disposal of fly-ash (FA) from coal-fired power stations causes significant economic and environmental problems. Use of such contaminated sites for crop production and use of contaminated water for irrigation not only decreases crop productivity but also poses health hazards to humans due to accumulation of toxic metals in edible grains. In the present investigation, three rice cultivars viz., Saryu-52, Sabha-5204, and Pant-4 were grown in garden soil (GS, control) and various amendments (10%, 25%, 50%, 75% and 100%) of FA for a period of 90 days and effect on growth and productivity of plant was evaluated vis-a-vis metal accumulation in the plants. The toxicity of FA at higher concentration (50%) was reflected by the reduction in photosynthetic pigments, protein and growth parameters viz., plant height, root biomass, number of tillers, grain and straw weight. However, at lower concentrations (10-25%), FA enhanced growth of the plants as evident by the increase of studied growth parameters. The cysteine and non-protein thiol (NP-SH) content showed increase in their levels up to 100% FA as compared to control, however, maximum content was found at 25% FA in Saryu-52 and Pant-4 and at 50% FA in Sabha-5204. Accumulation of Fe, Si, Cu, Zn, Mn, Ni, Cd and As was investigated in roots, leaves and seeds of the plants. Fe accumulation was maximum in all the parts of plant followed by Si and both showed more translocation to leaves while Mn, Zn, Cu, Ni and Cd showed lower accumulation and most of the metal was confined to roots in all the three cultivars. As was accumulated only in leaves and was not found to be in detectable levels in roots and seeds. The metal accumulation order in three rice cultivars was Fe > Si > Mn > Zn > Ni > Cu > Cd > As in all the plant parts. The results showed that rice varieties Saryu-52 and Sabha-5204 were more tolerant and could show improved growth and yield in lower FA application doses as compared to Pant-4. Thus, Sabha-5204 and Saryu-52 are found suitable for cultivation in FA amended agricultural soils for better crop yields.

Effect of Bradykinin on Murrah buffalo (Bubalus bubalis) semen cryopreservation

Keeping in view the poor freezability of bubaline semen in conventionally used extenders, this study was conducted on three Murrah bulls to improve semen cryopreservation with the incorporation of Bradykinin (0.5, 1.0 and 2.0 ng ml(-1)) in routinely used egg yolk tris-glycerol (EYTG) extender. Bradykinin (2.0 ng ml(-1)) had significant (P<0.05) beneficial effect on live sperm % (81.6+/-1.8) and hypo osmotic swelling (HOS) % (63.0+/-1.3) as compared to their respective control values of 73.4+/-2.1 and 56.3+/-2.0 at 0 h post freezing. The post-thaw progressive sperm motility in semen samples diluted with EYTG containing 2.0 ng ml(-1) Bradykinin (65.5+/-1.4) was also significantly (P<0.01) higher than control (60.3+/-1.9) at 0 h post freezing. Thus incorporation of 2 ng ml(-1) Bradykinin in buffalo semen diluted in EYTG extender may be useful in improving the quality of cryopreserved bubaline semen.

Theoretical Study of Interaction of Urate with Li+, Na+, K+, Be2+, Mg2+, and Ca2+ Metal Cations

The geometries and energetics of complexes of Li(+), Na(+), K(+), Be(2+), Mg(2+), and Ca(2+)metal cations with different possible uric acid anions (urate) were studied. The complexes were optimized at the B3LYP level and the 6-311++G(d,p) basis set. Complexes of urate with Mg(2+), and Ca(2+)metal cations were also optimized at the MP2/6-31+G(d) level. Single point energy calculations were performed at the MP2/6-311++G(d,p) level. The interactions of the metal cations at different nucleophilic sites of various possible urate were considered. It was revealed that metal cations would interact with urate in a bi-coordinate manner. In the gas phase, the most preferred position for the interaction of Li(+), Na(+), and K(+) cations is between the N(3) and O(2) sites, while all divalent cations Be(2+), Mg(2+), and Ca(2+) prefer binding between the N(7) and O(6) sites of the corresponding urate. The influence of aqueous solvent on the relative stability of different complexes has been examined using the Tomasi's polarized continuum model. The basis set superposition error (BSSE) corrected interaction energy was also computed for complexes. The AIM theory has been applied to analyze the properties of the bond critical points (electron densities and their Laplacians) involved in the coordination between urate and the metal cations. It was revealed that aqueous solvation would have significant effect on the relative stability of complexes obtained by the interaction of urate with Mg(2+) and Ca(2+)cations. Consequently, several complexes were found to exist in the water solution. The effect of metal cations on different NH and CO stretching vibrational modes of uric acid has also been discussed.

Effect of Hydration on the Lowest Singlet ππ* Excited-State Geometry of Guanine: A Theoretical Study

An ab-initio computational study was performed to investigate the effect of explicit hydration on the ground and lowest singlet PiPi* excited-state geometry and on the selected stretching vibrational frequencies corresponding to the different NH sites of the guanine acting as hydrogen-bond donors. The studied systems consisted of guanine interacting with one, three, five, six, and seven water molecules. Ground-state geometries were optimized at the HF level, while excited-state geometries were optimized at the CIS level. The 6-311G(d,p) basis set was used in all calculations. The nature of potential energy surfaces was ascertained via the harmonic vibrational frequency analysis; all structures were found minima at the respective potential energy surfaces. The changes in the geometry and the stretching vibrational frequencies of hydrogen-bond-donating sites of the guanine in the ground and excited state consequent to the hydration are discussed. It was found that the first solvation shell of the guanine can accommodate up to six water molecules. The addition of the another water molecule distorts the hydrogen-bonding network by displacing other neighboring water molecules away from the guanine plane.

Excited State Proton Transfer in Guanine in the Gas Phase and in Water Solution: A Theoretical Study

Theoretical investigations were performed to study the phenomena of ground and electronic excited state proton transfer in the isolated and monohydrated forms of guanine. Ground and transition state geometries were optimized at both the B3LYP/6-311++G(d,p) and HF/6-311G(d,p) levels. The geometries of tautomers including those of transition states corresponding to the proton transfer from the keto to the enol form of guanine were also optimized in the lowest singlet pipi* excited state using the configuration interaction singles (CIS) method and the 6-311G(d,p) basis set. The time-dependent density function theory method augmented with the B3LYP functional (TD-B3LYP) and the 6-311++G(d,p) basis set was used to compute vertical transition energies using the B3LYP/6-311++G(d,p) geometries. The TD-B3LYP/6-311++G(d,p) calculations were also performed using the CIS/6-311G(d,p) geometries to predict the adiabatic transition energies of different tautomers and the excited state proton transfer barrier heights of guanine tautomerization. The effect of the bulk aqueous environment was considered using the polarizable continuum model (PCM). The harmonic vibrational frequency calculations were performed to ascertain the nature of potential energy surfaces. The excited state geometries including that of transition states were found to be largely nonplanar. The nonplanar fragment was mostly localized in the six-membered ring. Geometries of the hydrated transition states in the ground and lowest singlet pipi* excited states were found to be zwitterionic in which the water molecule is in the form of hydronium cation (H3O(+)) and guanine is in the anionic form, except for the N9H form in the excited state where water molecule is in the hydroxyl anionic form (OH(-)) and the guanine is in the cationic form. It was found that proton transfer is characterized by a high barrier height both in the gas phase and in the bulk water solution. The explicit inclusion of a water molecule in the proton transfer reaction path reduces the barrier height drastically. The excited state barrier height was generally found to be increased as compared to that in the ground state. On the basis of the current theoretical calculation it appears that the singlet electronic excitation of guanine may not facilitate the excited state proton transfer corresponding to the tautomerization of the keto to the enol form.

TDDFT investigation on nucleic acid bases: comparison with experiments and standard approach

A comprehensive theoretical study of electronic transitions of canonical nucleic acid bases, namely guanine, adenine, cytosine, uracil, and thymine, was performed. Ground state geometries were optimized at the MP2/6-311G(d,p) level. The nature of respective potential energy surfaces was determined using the harmonic vibrational frequency analysis. The MP2 optimized geometries were used to compute electronic vertical singlet transition energies at the time-dependent density functional theory (TDDFT) level using the B3LYP functional. The 6-311++G(d,p), 6-311(2+,2+)G(d,p), 6-311(3+,3+)G(df,pd), and 6-311(5+,5+)G(df,pd) basis sets were used for the transition energy calculations. Computed transition energies were found in good agreement with the corresponding experimental data. However, in higher transitions, the Rydberg contaminations were also obtained. The existence of pisigma* type Rydberg transition was found near the lowest singlet pipi* state of all bases, which may be responsible for the ultrafast deactivation process in nucleic acid bases.

Electronic spectra of adenine and 2-aminopurine: an ab initio study of energy level diagrams of different tautomers in gas phase and aqueous solution

Ground and lowest two singlet excited state geometries of four tautomeric forms (N9H, N7H, N3H and N1H) of each of adenine and 2-aminopurine (2AP) were optimized using an ab initio approach employing a mixed basis set (6-311 + G* on the nitrogen atom of the amino group and 4-31G basis set on the other atoms). Excited states were generated employing configuration interaction involving single electron excitations (CIS). Subsequently, the different species were solvated in water employing the self-consistent reaction field (SCRF) approach along with the corresponding gas phase optimized geometries. Thus the observed absorption and fluorescence spectra of adenine and 2AP have been explained successfully. It is concluded that both the N9H and N7H forms of 2AP would contribute to absorption and fluorescence spectra. Further, the fluorescence of 2AP would be absorbed by its cation in which both the N9 and N7 atoms are protonated, the fluorescence of which can have an anti-Stokes component. Among the different tautomers of adenine, the N9H form would be present dominantly in the ground state in aqueous solutions but the N7H form would be produced by energy transfer and subsequent fluorescence. The N3H form of adenine appears to be responsible for the observed absorption near 300 nm by its solutions intermittently exposed to ultraviolet radiation. The rings of the different species related to 2AP and adenine remain almost planar in the pi-pi* and n-pi* singlet excited states as in the ground state. The pyramidal character of the amino group is usually less in the pi-pi* excited states than that in the corresponding ground or n-pi* excited states. Molecular electrostatic potential (MEP) maps of the molecules provide useful clues regarding phototautomerism.

A geometry optimization and molecular electrostatic potential mapping study of structure-activity relationship for some anti-Alzheimer agents

Molecular geometries of some substituted (pyrroloamino)pyridines which possess anti-Alzheimer activity were optimized and potential-derived CHelpG point charges were computed using ab initio SCF molecular orbital approach employing the 3-21G basis set. AM1 molecular orbital calculations were performed using these optimized geometries and thus optimized Hybridization. Displacement Charges (HDC) combined with Löwdin charges continuously distributed in three dimension were obtained. Molecular electrostatic potential (MEP) maps of the molecules were obtained in two ways: (i) using the HDC-based model with the help of which MEP minima near the molecules were located, and (ii) using the CHelpG point charges, MEP values on the van der Waals surfaces of the molecules were computed. The MEP maps computed using both the methods have negative MEP regions near the pyridine nitrogen atom which appears to be the main binding site of the molecules with the appropriate receptor. Both electrostatic interaction and lipophilic association between these molecules and the receptor appear to contribute to biological activity.

Therapeutic potential of meso 2,3-dimercaptosuccinic acid or 2,3-dimercaptopropane 1-sulfonate in chronic arsenic intoxication in rats

The therapeutic efficacy of two thiol chelators, meso 2,3-dimercaptosuccinic acid (DMSA) or 2,3-dimercaptopropane sulfonate (DMPS) in treating chronic arsenic intoxication was investigated in male rats. Both the chelators were effective in promoting urinary arsenic excretion and restoring arsenic induced inhibition of blood delta-aminolevulinic acid dehydratase activity and hepatic glutathione level. Elevation of urinary delta-aminolevulinic acid excretion and arsenic concentration in blood, liver and kidneys were reduced significantly by both the chelators. Histopathological lesions induced by arsenic were also effectively reduced by the above chelators. DMSA being more effective than DMPS. The results suggest DMSA and DMPS to be effective antidotes for treating chronic arsenic toxicity in experimental animals.

Plasma prolactin as an indicator of disease progression in advanced breast cancer

Serial plasma prolactin levels were measured in 144 breast cancer patients (premenopausal [PR-M], N = 64; postmenopausal [PO-M], N = 80) and compared with respective controls. Patients with breast cancer were grouped into those who (1) developed distant metastasis, (2) developed local recurrence, (3) stable disease, and (4) responded to the various therapeutic modalities at the end of 2 years. The authors' analysis showed excellent correlation between serial plasma prolactin changes and the response to therapy or progression of disease in patients with advanced breast carcinoma.

Prognosis in breast carcinoma utilizing plasma carcinoembryonic antigen and histologic characteristics of the primary tumor

Plasma carcinoembryonic antigen (CEA) concentrations in 128 patients with breast cancer were measured preoperatively. The data were related to the histologic features of the primary breast carcinoma and to the clinical follow-up data. Analysis of the plasma CEA values did not show a significant correlation with the histologic type and the histologic and nuclear grade of the primary tumor (n = 73) as well as to the presence or absence of keratin, necrosis, desmoplasia, tubule formation and mucin production. Furthermore, the results indicated that high CEA values (more than 10 ng/ml) may be associated with distant metastasis and not with the metastatic spread to lymph nodes. High CEA levels were also associated with reduced survival of the patients. This study confirms our previous report suggesting that high CEA levels are correlated with tumors of endodermal origin, whereas the CEA levels were within the normal range in the tumors of ectodermal origin. In agreement with other studies, however, it was found that the predictive value of plasma CEA concentrations in general is weak, so that the use of CEA measurement for prognosis is of limited value.