Escherichia coli expression and characterization of α-amylase from Geobacillus thermodenitrificans DSM-465

Alpha amylase, catalyzing the hydrolysis of starch is a ubiquitous enzyme with tremendous industrial applications. A 1698 bp gene coding for 565 amino acid amylase was PCR amplified from Geobacillus thermodenitrificans DSM-465, cloned in pET21a (+) plasmid, expressed in BL21 (DE3) strain of E. coli and characterized. The recombinant enzyme exhibited molecular weight of 63 kDa, optimum pH 8, optimum temperature 70°C, and KM value of 157.7µM. On pilot scale, the purified enzyme efficiently removed up to 95% starch from the cotton fabric indicating its desizing ability at high temperature. 3D model of enzyme built by Raptor-X and validated by Ramachandran plot appeared as a monomer having 31% α-helices, 15% β-sheets, and 52% loops. Docking studies have shown the best binding affinity of enzyme with amylopectin (∆G -10.59). According to our results, Asp 232, Glu274, Arg448, Glu385, Asp34, Asn276, and Arg175 constitute the potential active site of enzyme.

Anion-Cation Replacement Effect on the Structural and Optoelectronic Properties of the LiMX2 (M = Al, Ga, In; X = S, Se, Te) Compounds: A First Principles Study

In the chalcopyrite (or tetragonal) phase, different physical properties of the ternary LiMX2 (M = Al, Ga, In and X = S, Se, Te) compounds are studied by the very accurate density functional method. The optimized lattice constants and the bandgaps are close to the existing experimental data. In addition, for most of the LiMX2 compounds, when the cations change from Al to In and anions from S to Te, the lattice constant and equilibrium volume for the crystal unit cell increase whereas the bulk modulus decreases. Using different generalized gradient approximations, the band structure calculations are performed. Generally, it was observed that there exists a decreasing tendency of the bandgap energies except for the LiAlSe2, LiInSe2, and LiGaTe2 compounds due to the change from Al to In as well as the change from S to Te. The bonding analysis shows that ionic bonds are present between the Li-X atoms, while a covalent bond exists between the M cations and X anions. The optical properties of the compounds are studied by calculating the real and imaginary components of the refractive index, reflectivity, optical conductivity, and birefringence. In addition, the optical properties from the calculations show that these materials are appropriate applicants to be utilized as Bragg’s reflector or applied in optoelectronic and solar cell technology.

IDENTIFICATION OF QTLs ON CHROMOSOME 1B FOR GRAIN QUALITY TRAITS IN BREAD WHEAT (TRITICUM AESTIVUM L.)

The present study was designed considering the importance of grain quality traits, genetic diversity and marker-trait association analysis in wheat. A significant amount of genetic diversity was found for various seed traits though the genotypes included in the study were found structured. The extent of polymorphism was high with a range of 2-13 alleles and average of 6.5 alleles per locus. Population structure was detected with 30 unlinked SSRs that divided the population of 92 genotypes in three sub-populations. Extensive LD extent was found on chromosome 1B with 42 SSRs specific for 1B chromosome. Marker-trait associations were determined using mixed linear model, where, population structure and kinship calculated on the basis of unlinked markers were covariated with 1B specific markers and traits data. Eight QTLs for five traits including protein, gluten contents, test weight bread and chapati making quality. Protein content, test weight, bread quality and Glu-B1 were found significantly associated with primers WMC419 (32 cM); WMC128 (30 cM), WMC419 (32 cM); WMC818 (17 cM) and WMC416 (44 cM), respectively.

Stainless steel crowns reuse and decontamination techniques: a survey among Indian pediatric dentists

OBJECTIVE

To determine the pattern and extent of stainless steel crown (SSC) reuse following try-in and the methods employed for their decontamination among Indian pediatric dentists.

STUDY DESIGN

Questionnaires were delivered personally to 100 pediatric dentists selected randomly across India. Questionnaire was divided into three subsections. The first section assessed demographics to determine the sample population characteristics. The second section dealt with the pattern of SSCs use and reuse following size determination. The third section inquired into general cross infection control procedures including cleaning, sterilization, and training to assess the general level of compliance. Data analysis involved descriptive analysis using SPSS 16.0 software.

RESULTS

The majority of respondents (98.92%) routinely reused the crowns after they had been tried in the patient. Only one respondent (1.08%) discarded the crowns after try-in. Autoclave (25%) was the most common method employed for the decontamination of tried-in SSCs among the respondents.

CONCLUSION

The majority of the participating pediatric dentists are reusing SSCs following try-in during crown selection. However, great diversity exists in the methods employed for the decontamination of the same. This demands for more research to provide guidelines into the most effective method of decontamination.

Investigation of 3'-debenzoyl-3'-(3-([¹²⁴I]-iodobenzoyl))paclitaxel analog as a radio-tracer to study multidrug resistance in vivo

A study was carried out to identify a suitable radioactive paclitaxel analog and to use it to investigate tumor multidrug resistance in vivo. 3'-Debenzoyl-3'-(3-([(124)I]-iodobenzoyl))paclitaxel was prepared by aromatic iodination of 3'-debenzoyl-3'-(3-trimethylstannylbenzoyl)paclitaxel. Uptake of the labeled paclitaxel analog in nude mice bearing tumor with the paclitaxel sensitive cancer cell lines MCF7 and MDA-435/LCC6(WT), and multidrug resistant cell lines NCI/ADR-RES and MDA-435/LCC6(MDR), was studied. There was no difference in drug level between the sensitive and resistant MDA-435/LCC6 tumors at 6h post-injection. However, at 6h, there was a significant increase in drug level for the MCF7 tumor as compared with the NCI/ADR-RES tumor, presumably due to increased drug retention. At 24h, drug uptake/retention was significantly higher in both sensitive tumor cell lines as compared to their drug resistant counterparts. Pretreatment of mice with MDR transport modulators, Cyclosporine or tRA 96029, did not increase the level of labeled paclitaxel analog in the drug resistant MDA-435/LCC6(MDR) tumor. On the other hand, at 24h Cyclosporine apparently increased analog level in the drug sensitive MDA-435/LCC6(WT) tumor, aiding drug imaging studies.

A novel compact design of calibration equipment for gas and thermal sensors

A novel design of calibration equipment has been developed for static and dynamic calibrations of gas and thermal sensors. This system is cheap, compact, and easily adjustable, which is also combined with a plasma surface modification source for tailoring the surface of sensors to ensure the sensitivity and selectivity. The main advantage of this equipment is that the operating temperature, bias voltage, types of plasma source (for surface modification), types of feeding gases, and gas flow rate (for calibrations), etc., can be independently controlled. This novel system provides a highly reliable, reproducible, and economical method of calibrations for various gas and thermal sensors.

Effects of novel heparin-derived compounds on tumor uptake of chemotherapeutics and chemoresponse

2537

Thrombotic complications are the second most common cause of mortality in cancer patients and fibrin deposition in the tumor microenvironment might play a key role in tumor progression and inference with tumor chemotherapeutic uptake. Treatments that target these processes may result in improved uptake of chemotherapeutic agents and subsequent inhibition of tumor growth and metastasis. Tissue Factor (TF) is frequently associated with aggressive behavior and poor outcome in tumors. We have previously demonstrated potent anti-tumor efficacy for various mechanisms that interfere with TF/VIIa. The purpose of this study was to investigate the effects of low molecular weight heparins (LMWH) and sulfated non-anticoagulant LMWH (S-NACH) on tumor chemotherapeutic uptake. Studies: (1) Nude mice xenograft A549 human lung carcinoma: LMWH or S-NACH at 10 mg/kg S.C. daily effectively limited tumor growth. (2) LCC6 human lung tumor xenograft model: Paclitaxel alone or in combination with Tinzaparin or S-NACH on tumor re-growth after discontinuation of treatment: Paclitaxel + S-NACH treatment showed significant (P<0.01) tumor growth suppression and improved survival when compared to Paclitaxel. (3) Biodistribution studies: animals were injected with LMWH S.C. daily for 5 days (10 mg/kg) then injected i.v. with [124-I]-Paclitaxel. LMWH increased [124-I]-Paclitaxel uptake into LCC6 tumors with tumor: muscle ratios several fold greater than that of [124-I]-Paclitaxel alone at 24 hrs post injection. This is a highly significant result in the light of the fact that the FDA criterion for a clinically meaningful effect is a 15% increase in uptake. (4) HPLC studies of tumor uptake of Doxorubicin (DOX in mice treated with 10 mg/kg of LMWH or S-NACH for 10 days followed by Doxorubicin (2.5 mg/kg). Both LMWH and S-NACH significantly (P<0.01) increased the uptake of chemotherapeutic agent DOX in MCF7 DOX resistant tumors by 1.5–2 folds but not in heart or lung tissues, confirming the findings obtained with another agent [124-I]-Paclitaxel. Conclusions: LMWH or S-NACH increased chemotherapeutics uptake and hence chemoresponse. Protocols utilizing adjuvant or neo-adjuvant therapy with LMWH or S-NACH could lead to increase tumor chemo responsiveness and overcoming tumor chemo resistance.

No significant financial relationships to disclose.

Outpatient treatment of spontaneous pneumothorax using an improved pocket sized Heimlich valve

We report two patients, who have used Pneumostat to replace the conventional underwater seal drainage system for recurrent pneumothorax. Both patients had required repeated chest tube insertion for recurrent pneumothorax and needed a longer hospital stay. Both patients were able to be discharged with the Pneumostat device and were reviewed in outpatient clinic. Both patients had optimal clinical improvement and chest X-ray showed no residual pneumothorax.

A system for continuous production and infusion of [15O]H2O for PET activation studies

A system for continuous production and infusion of [15O]H2O has been designed for Positron Emission Tomography brain activation studies. The infusion system consists of two Horizon Nxt infusion pumps, a four-port-two-position valve and a sterile 50 ml vial. The line and the back check valve between the furnace and the reservoir were heated in order to reduce vapor condensation in the line. The variation of the production of [15O]H2O was < 1%. The activity delivered as measured by scanner counts varied < 2% during the steady state period. The system has been demonstrated to be capable of delivering activity over a wide range of conditions.

An automated [15Q]H2O production and injection system for PET imaging

A computer controlled [15O]H2O injection system has been designed for multiple bolus injections during PET cerebral blood flow studies. The system is housed in a lead safe, and radiation exposure to nearby personnel is low; we have measured rates of approx. 100 microSv/h (10 mR/h) during 2 min of [15O]H2O production and < 50 microSv/h (< 5 mR/h) after 3.7 GBq (100 mCi) has been produced. Reproducibility studies show that the injected activity varies with a coefficient of variation of 2-3%.

Synthesis of 2-[123I and 124I]-iodoisonicotinic acid hydrazide--potential radiotracers for tuberculosis

The radiochemical syntheses of methyl 2-[123I]-iodoisonicotinate, 2-[123I]-iodoisonicotinic acid hydrazide and 2-[124I]-iodoisonicotinic acid hydrazide was accomplished. Iodine-123 was incorporated in the methyl ester molecule by an exchange reaction in glacial acetic acid. The average efficiency of iodine exchange reaction was (92.6 +/- 4.5)%. This radiotracer was extracted with ether and the solvent was evaporated. The residue was re-dissolved in anhydrous ethanol and treated with hydrazine under anhydrous conditions to obtain 2-[123I]-iodoisonicotinic acid hydrazide. The overall radiochemical yield was 69%. Biodistribution data of both radio-tracers in male Sprague-Dawley rats were collected. This is the first report of SPECT radiopharmaceuticals which may be useful for differential diagnosis of intracranial masses (tuberculoma vs glioma), and CNS tuberculosis in immunosuppressed subjects.

High specific activity 15-(p-[123I]iodophenyl)pentadecanoic acid

An improved labeling procedure for 15-(p-[123I]iodophenyl)pentadecanoic acid (IPPA) is reported. The exchange labeling yield was greater than 95%. The radiochemical yield is influenced by the presence of sodium. The major advantage of this method is that very high specific activity i.e. upto 190 mCi/mg labeled IPPA can be prepared.

Synthesis of 15O-labeled butanol via organoborane chemistry

Oxygen-15 labeled 1-butanol and 2-butanol were prepared by the reaction of O2-15O with tri-n-butylborane and tri-sec-butylborane in tetrahydrofuran. The reaction products were isolated and identified via reversed-phase high performance column chromatography and gas chromatography. Radiochemical yields of 50% (EOB) were obtained. The use of 15O-labeled butanol is suggested for cerebral blood flow measurements in conjunction with PET.