Comparison of methods used for the determination of cholinesterase activity in whole blood

Cholinesterases (ChEs) are classified as either acetylcholinesterase (AChE) or butyrylcholinesterase (BChE) based on their substrate and inhibitor specificity. Organophosphate and carbamate compounds commonly represented by herbicides, pesticides, and nerve gases irreversibly inhibit ChEs. Therefore, exposure to organophosphates and carbamates is normally assessed by measuring ChE activity in blood. There are two approaches for measuring AChE and BChE activity present in whole blood: (1) separating blood into erythrocytes, which contain only AChE, and plasma which contains only BChE, to measure their activity individually, or (2) use a BChE-specific inhibitor to measure the activity of AChE in whole blood. A number of studies have reported the use of different inhibitors for the simultaneous measurement of AChE and BChE activities. However, the inhibitors used for completely inhibiting BChE activity also inhibited AChE activity leading to errors in reported values. The goal of this study was to find the most accurate and simple method for the simultaneous determination of AChE and BChE activity in animal whole blood. Solutions containing human AChE and BChE in various proportions were prepared and AChE and BChE activities were measured using three reported methods. Results demonstrate that ethopropazine and (-) huperzine A appear to be the most specific ChE inhibitors. Preliminary results with human and animal whole blood suggest that 20muM ethopropazine and 500nM (-) huperzine A can be used for measuring AChE and BChE activities across species.     

DNA organization by the apicoplast-targeted bacterial histone-like protein of Plasmodium falciparum

Apicomplexans, including the pathogens Plasmodium and Toxoplasma, carry a nonphotosynthetic plastid of secondary endosymbiotic origin called the apicoplast. The P. falciparum apicoplast contains a 35 kb, circular DNA genome with limited coding capacity that lacks genes encoding proteins for DNA organization and replication. We report identification of a nuclear-encoded bacterial histone-like protein (PfHU) involved in DNA compaction in the apicoplast. PfHU is associated with apicoplast DNA and is expressed throughout the parasite's intra-erythocytic cycle. The protein binds DNA in a sequence nonspecific manner with a minimum binding site length of ~27 bp and a K_d of ~63 nM and displays a preference for supercoiled DNA. PfHU is capable of condensing Escherichia coli nucleoids in vivo indicating its role in DNA compaction. The unique 42 aa C-terminal extension of PfHU influences its DNA condensation properties. In contrast to bacterial HUs that bend DNA, PfHU promotes concatenation of linear DNA and inhibits DNA circularization. Atomic Force Microscopic study of PfHU–DNA complexes shows protein concentration-dependent DNA stiffening, intermolecular bundling and formation of DNA bridges followed by assembly of condensed DNA networks. Our results provide the first functional characterization of an apicomplexan HU protein and provide additional evidence for red algal ancestry of the apicoplast.     

Carbon and Nitrogen Mineralization of Lead Treated Soils in the Eastern Mediterranean Region,Turkey

The aim of this study was to determine the first effect of lead on microbial activity in soil. The study was carried out in the soil samples from four different radish (Raphanus sativus L. var. radicula, Brassicaceae) fields along the highway in a district (Kadirli, Osmaniye) of the Eastern Mediterranean Region, Turkey. After the calculation of Pb contents, the Pb amounts of the soil samples were brought up to 50 and 100 mg Pb kg^?1 by treatment with Pb(NO ₃ ) ₂ , and the samples for the carbon and the nitrogen mineralization were incubated under controlled conditions (28°C, constant moist). The carbon mineralization was determined by a CO ₂ respiration method for 30 days. The nitrogen mineralization was observed in vitro for 6 weeks. The untreated group was statistically different from the 50 and 100 mg Pb kg^?1 treatments in the aspect of the C(CO ₂ ) outlet during mineralization (P ≤ 0.05), but difference between the 50 and 100 mg Pb kg^?1 treatments was not significant. NH ₄ -N and NO ₃ -N contents of each soil were shown differences between across treatments. Based on these results, it is possible to conclude that the addition of 50 and 100 mg Pb kg^?1 provided a toxic effect threshold for the microbial activity into 30 days.     

Occult medullary carcinoma of thyroid with lymph node metastases: a case report

BACKGROUND: Occult thyroid malignancies presenting with secondary neck masses as the first clinical manifestation is well known. Although rare, medullary carcinoma serves a potential source for lymph node metastases. The characteristic cytomorphology of medullary thyroid carcinoma (MTC) should clinch the diagnosis. Further, fine needle aspiration cytology (FNAC) of the ultrasonography-detected occult nodules in thyroid serves as a useful preoperative diagnostic tool. CASE: A 22-year-old man presented with left-sided neck masses of 1 year duration. FNAC smears of the neck masses revealed cytomorphology characteristic of MTC. Ultrasonography of the thyroid led to ruling out the presence of an occult nodule and detected an 8-mm nodule in the left thyroid lobe. Ultrasound-guided FNAC of the nodule showed features similar to those with FNAC of the neck masses. Surgical resection of thyroid and neck masses further confirmed the diagnosis of a primary occult MTC with lymph node metastases. CONCLUSION: FNAC smears of lymph node masses showing the distinct cytomorphology of MTC should prompt suspicion for occult primary in thyroid. Ultrasound-guided FNAC of these occult nodules, if detected, further serves a diagnostic tool for accurate preoperative diagnosis when metastasis presents as the first clinical manifestation of an occult primary.     

Sago: An Alternative Cheap Gelling Agent for Potato In Vitro Culture

Sago, a processed (gelatinized) edible starch, was successfully used as a gelling agent in culture medium. The efficacy of sago-gelled (80 g dm^–3) medium was studied in ten potato (Solanum tuberosum L.) genotypes during micropropagation and minimal growth conservation. Sago starch provided a firm gelling surface throughout the entire culture period, and fostered optimum plantlet growth in terms of shoot height, number of nodes per plant, number of leaves and fresh mass. No softening of the sago-gelled medium occurred over prolonged (six months) storage. The study showed that sago starch could be used as a substitute to agar in culture medium to substantially reduce the medium cost.     

Incidence of mycoflora and mycotoxins in some edible fruits and seeds of forest origin

Twelve fungi namelyAlternaria alternata, Aspergillus flavus, A niger, A ochraceus, Actinomucor repens, Capnodoium spp., Curvularia lunata, Fusarium pallidoroseum, F solani, F verticillioides, Penicillium citrinum and Rhizopus stolonifer were recorded from samples ofAegle marmelos, Aesculus indica, Buchanania lanzan andPinus gerardiana. In case ofPrunus amygdalus only Rstolonifer was recorded. A significant variation in pattern of mycoflora incidence was observed in terms of source and season. Fungal infestation in most of the substrates was found to be highest during monsoon. Aflatoxins were the most common mycotoxins elaborated by different isolates ofA flavus obtained fromA marmelos, B lanzan andP gerardiana. The amount of aflatoxins produced by the toxigenic isolates ofA flavus was in the range of traces to 0.9–26.0 μg/ml inA marmelos, 0.8–17.5 μg/ml inP gerardiana and 0.65–13.2 μg/ml inB lanzan. The percentage toxigenicity was comparatively lower in the isolates of other mycotoxigenic fungi. Aflatoxins were detected almost in all the samples analyzed for mycotoxin contamination. However, traces of zearalenone were detected inA marmelos. The concentration of aflatoxin B₁ was in the range of 0.13–0.75 μg/g inA marmelos, 0.09–0.60 μg/g inP gerardiana and 0.01–0.20 ug/g inB lanzan. Mycotoxins were not detected inAesculus indica andPrunus amygdalus.     

Respiratory responses and blood sugar level of the crab, Barytelphusa cunicularis (Westwood), exposed to mercury, copper and zinc.

Barytelphusa cunicularis (Westwood), a freshwater crab was exposed to mercuric chloride, copper sulphate and zinc sulphate from 0 to 12 hr and the oxygen consumption of the animal was measured in order to study the stress caused by these heavy metals. Normal oxygen consumption was affected by the three heavy metals. Similarly, crabs exposed to sublethal concentrations of the same pollutants for 24, 48, 72 and 96 hr showed an elevation in the blood sugar level with a maximum increase at 48 hr. The results indicate a switch towards glycolysis in order to overcome the anaerobic stress caused by the heavy metals.