Specific Detection of Pacific Oyster (Crassostrea gigas) Larvae in Plankton Samples Using Nested Polymerase Chain Reaction

Management of sustainable Pacific oyster fisheries would be assisted by an early, rapid, and accurate means of detecting their planktonic larvae. Reported here is an approach, based on polymerase chain reaction (PCR), for the detection of Pacific oyster larvae in plankton samples. Species-specific primers were designed by comparing partial mitochondrial cytochrome oxidase subunit I (COI) sequences from Crassostrea gigas, with other members of the family Ostreidae including those of Crassostrea angulata. Assay specificity was empirically validated through screening DNA samples obtained from several species of oysters. The assay was specific as only C. gigas samples returned PCR-positive results. A nested PCR approach could consistently detect 5 or more D-hinge-stage larvae spiked into a background of about 146 mg of plankton. The assay does not require prior sorting of larvae. We conclude that the assay could be used to screen environmental and ballast water samples, although further specificity testing against local bivalve species is recommended in new locations.     

Synthesis and antibacterial activity of novel (un)substituted benzotriazolyl oxazolidinone derivatives

A series of novel (un)substituted benzotriazolyl oxazolidinone derivatives has been synthesized and tested for in vitro antibacterial activities by MIC determination against a panel of susceptible and resistant Gram-positive and Gram-negative microorganisms, some of which are resistant to methicillin and vancomycin. Compounds 20, 21, 24, 29 and 30 from this series were found to be equipotent or more potent than linezolid in vitro.     

Bioconversion of 3 beta-acetoxypregna-5,16-diene-20-one to androsta-1,4-diene-3,17-dione by mixed bacterial culture

AIMS: To isolate a bacterium capable of degrading 3 beta-acetoxypregna-5,16-diene-20-one (16-DPA) to androsta-1,4-diene-3,17-dione (ADD) and to decipher the biodegradation pathway. METHODS AND RESULTS: Isolation on mineral salt agar containing 16-DPA as sole carbon source yielded two bacteria identified as Pseudomonas diminuta and Comamonas acidovorons. These bacteria failed to degrade 16-DPA individually in pure cultures but converted 16-DPA to ADD in a mixed culture. The intermediates accumulated during the bioconversion were identified as pregna-4,16-diene-3,20-dione and pregna-1,4,16-triene-3,20-dione. CONCLUSIONS: The degradation pattern of 16-DPA by mixed bacterial culture revealed the reaction sequence as (i) cleavage of C-3 acetyl function, (ii) dehydrogenation at C-1 and C-2 positions and (iii) cleavage of C-17 side-chain. SIGNIFICANCE AND IMPACT OF THE STUDY: The present work opens a new approach towards the production of a female sex hormone precursor and elucidates the biodegradation pathway of 16-DPA by mixed bacterial culture.     

Influence of fungal elicitors on production of ajmalicine by cell cultures of Catharanthus roseus

Suspension cultures of Catharanthus roseus (C. roseus) were elicited with fungal cell wall fragments of Aspergillus niger (A. niger), Fusarium moniliforme (F. moniliforme), and Trichoderma viride (T. viride). The effects of elicitor dosage, exposures time, and age of subculture on ajmalicine accumulation were studied. A higher concentration of elicitor extract responded positively to C. roseus suspension cultures. Ajmalicine accumulation increased by about 3-fold when cells were treated with A. niger, F.moniliforme, and T. viride. The maximum ajmalicine production (75 microg g(-1) dry weight (DW)) was observed in cells treated with T. viride. Cell cultures were elicited with 5% preparation of A. niger, F. moniliforme, and T. viride and exposed for 24, 48, 72, and 96 h. for elicitation. Suspension cultures elicited with T. viride for 48 h showed a 3-fold increase (87 microg g(-1) DW) in ajmalicine contents, whereas A. niger and F. moniliforme synthesized a 2-fold increase in alkaloid and yielded 52 and 56 microg g(-1) DW ajmalicine, respectively. C. roseus cells of different age (5,10, 15, 20, and 25 days old) were treated with a 5% elicitor of A. niger, F. moniliforme, and T. viride and investigated elicitors activity at different age of cell cultures. Maximum yield 166 microg g(-1) DW of ajmalicine was synthesized in 20 day old suspension cultures treated with T. viride. A longer period of incubation of cell cultures with elicitors adversely affected the ajmalicine synthesis.     

Formulation and roentgenographic studies of naproxen-pectin-based matrix tablets for colon drug delivery

A study has been carried out to assess the potential use of pectin in combination with two added hydrocolloids, i.e., hydroxy-propyl-methyl cellulose and hydroxyethyl cellulose in varied concentrations and coated with ethyl cellulose and cellulose acetate phthalate. The results of in vitro drug release showed that the matrix tablets prepared with pectin, hydroxy ethyl cellulose (20 percent) when coated with ethyl cellulose and cellulose acetate phthalate were found to be 63.0 percent, 8.4 percent, and 4.5 percent, respectively, in after eight hours during drug release study period. These results were confirmed with the results of roentgenographic studies in nine healthy human volunteers to find the shape and integrity of the dosage form. The X-ray photographs revealed that the enteric-coated tablet was visible only up to 5.5 hours and at the end of eighth hour, the photograph has not shown any presence of tablet indicating the loss of shape and size by the microflora present in the colon region. So, the results of in vitro and roentgenographic studies revealed that pectin, hydroxy ethyl cellulose (20 percent) base coated with ethyl cellulose and cellulose acetate phthalate was found to be a promising carrier for naproxen to colon.     

The radish Rfo restorer gene of Ogura cytoplasmic male sterility encodes a protein with multiple pentatricopeptide repeats

A single radish nuclear gene, Rfo, restores Ogura (ogu) cytoplasmic male sterility (CMS) in Brassica napus. A map-based cloning approach relying on synteny between radish and Arabidopsis was used to clone Rfo. A radish gene encoding a 687-amino-acid protein with a predicted mitochondrial targeting pre-sequence was found to confer male fertility upon transformation into ogu CMS B. napus. This gene, like the recently described Petunia Rf gene, codes for a pentatricopeptide repeat (PPR)-containing protein with multiple, in this case 16, PPR domains. Two similar genes that do not appear to function as Rfo flank this gene. Comparison of the Rfo region with the syntenic Arabidopsis region indicates that a PPR gene is not present at the Rfo-equivalent site in Arabidopsis, although a smaller and related PPR gene is found about 40 kb from this site. The implications of these findings for the evolution of restorer genes and other PPR encoding genes are discussed.     

Learning to control a brain-machine interface for reaching and grasping by primates

Reaching and grasping in primates depend on the coordination of neural activity in large frontoparietal ensembles. Here we demonstrate that primates can learn to reach and grasp virtual objects by controlling a robot arm through a closed-loop brain–machine interface (BMIc) that uses multiple mathematical models to extract several motor parameters (i.e., hand position, velocity, gripping force, and the EMGs of multiple arm muscles) from the electrical activity of frontoparietal neuronal ensembles. As single neurons typically contribute to the encoding of several motor parameters, we observed that high BMIc accuracy required recording from large neuronal ensembles. Continuous BMIc operation by monkeys led to significant improvements in both model predictions and behavioral performance. Using visual feedback, monkeys succeeded in producing robot reach-and-grasp movements even when their arms did not move. Learning to operate the BMIc was paralleled by functional reorganization in multiple cortical areas, suggesting that the dynamic properties of the BMIc were incorporated into motor and sensory cortical representations.     

Effect of 5-lipoxygenase inhibitor against lipopolysaccharide-induced hypothermia in mice

Bacterial endotoxin produces sepsis associated with alterations in body temperature (fever or hypothermia). The intraperitoneal administration of bacterial endotoxin, lipopolysaccharide (LPS; 50 microg/mouse) led to a decrease in colonic temperature starting 1 hr after the injection. The hypothermic effect was accompanied by a significant increase in hypothalamic leukotriene B4 (LTB4) and prostaglandin E2 (PGE2) levels. 5-lipoxygenase inhibitor, zileuton (200 and 400 mg/kg, po) administered 30 min before LPS challenge significantly prevented hypothermia. However, non-selective cyclooxygenase inhibitor, indomethacin (10, 20 mg/kg, po) did not reverse the hypothermic response. Further, pretreatment of mice with zileuton prevented LPS-stimulated increase in hypothalamic LTB4 levels and caused a relatively small increase in PGE2 levels. Indomethacin had no effect on LTB4 levels but it reduced PGE2 levels. These results suggest a possible involvement of leukotrienes in LPS-induced hypothermia and the potential protective role of 5-lipoxygenase inhibitors in endotoxemia.     

High-performance thin-layer chromatographic determination of lamotrigine in serum

A simple and rapid high-performance thin-layer chromatographic (HPTLC) determination of lamotrigine (LTG) in serum is reported. The method involves extraction of the drug by ethyl acetate followed by separation on TLC silica plates using a mixture of toluene-acetone-ammonia (7:3:0.5), as eluting solvent. Densitometric analysis was carried out at 312 nm with lamotrigine being detected at Rf of 0.54. The analytical method has excellent linearity (r=0.998) in the range of 20-300 ng/spot. This assay range is adequate for analyzing human serum, as it corresponds to lamotrigine concentrations measured in human serum from epileptic patients. The method was validated for sensitivity, selectivity, extraction efficiency, accuracy and intra and inter-day reproducibility. The limit of detection and limit of quantification were found to be 6.4 and 10.2 ng, respectively. Good accuracy is reported in the range of 92.06-97.12% and high precision with %CV in range of 0.53-2.59. The method was applied for determination of serum lamotrigine levels in epileptic patients and in pharmacokinetic study of lamotrigine administered orally to rabbits.