Lovastatin and (+)‐geodin production by Aspergillus terreus from crude glycerol

The use of pure substrate represents a significant proportion of the cost of manufacturing a drug such as lovastatin. This study explores the production of lovastatin and (+)‐geodin by Aspergillus terreus ATCC 20542 using biodiesel‐derived crude glycerol (CG) as a feedstock. Shake flask experiments showed reduced lovastatin production and glycerol consumption in the presence of 10–50 g/L CG with respect to pure glycerol controls. At 50 g/L, lovastatin and (+)‐geodin production was significantly reduced by 82 and 73%, respectively. The lowest lovastatin inhibition was detected in 30 g/L of CG (48%), which was accompanied by a significant rise in (+)‐geodin production (338%). Further investigation was performed on three major impurities found in CG, namely methanol (MeOH), sodium chloride (NaCl), and fatty acids (oleic acid and palmitic acid (PA), soap). None was particularly inhibitory for lovastatin, except soap and PAs, which reduced its production by more than 50% at all concentrations tested. In contrast, (+)‐geodin was inhibited in the presence of MeOH and PA by up to 46 and 91%, respectively. These observations indicate that partial purification of CG would be potentially useful in improving production of lovastatin and (+)‐geodin by A. terreus.     

Characterization of genetic diversity in chickpea using SSR markers,Start Codon Targeted Polymorphism (SCoT) and Conserved DNA-Derived Polymorphism (CDDP)

Physiology and Molecular Biology of Plants - To evaluate the genetic diversity among 48 genotypes of chickpea comprising cultivars, landraces and internationally developed improved lines genetic...     

Serotonin(4) (5-HT(4)) receptor agonists are putative antidepressants with a rapid onset of action

Current antidepressants are clinically effective only after several weeks of administration. Here, we show that serotonin(4) (5-HT(4)) agonists reduce immobility in the forced swimming test, displaying an antidepressant potential. Moreover, a 3 day regimen with such compounds modifies rat brain parameters considered to be key markers of antidepressant action, but that are observed only after 2-3 week treatments with classical molecules: desensitization of 5-HT(1A) autoreceptors, increased tonus on hippocampal postsynaptic 5-HT(1A) receptors, and enhanced phosphorylation of the CREB protein and neurogenesis in the hippocampus. In contrast, a 3 day treatment with the SSRI citalopram remains devoid of any effect on these parameters. Finally, a 3 day regimen with the 5-HT(4) agonist RS 67333 was sufficient to reduce both the hyperlocomotion induced by olfactory bulbectomy and the diminution of sucrose intake consecutive to a chronic mild stress. These findings point out 5-HT(4) receptor agonists as a putative class of antidepressants with a rapid onset of action.     

Normoxic polymer gel dosimetry using less toxic monomer of N-isopropyl acrylamide and X-ray computed tomography for radiation therapy applications

Background

Polymer gel dosimetry has been used extensively in radiation therapy for its capability in depicting a three dimensional view of absorbed dose distribution. However, more studies are required to find less toxic and more efficient polymers for application in radiotherapy dosimetry.

Aim

The purpose of this work was to evaluate the N-isopropyl acrylamide (NIPAM) gel dosimetric characteristics and optimize the protocol for X-ray computed tomography (CT) imaging of gel dosimeters for radiation therapy application.

Material and methods

A polymer gel dosimeter based on NIPAM monomer was prepared and irradiated with ⁶⁰Co photons. The CT number changes following irradiation were extracted from CT images obtained with different sets of imaging parameters.

Results

The results showed the dose sensitivity of ΔN_CT (H) = 0.282 ± 0.018 (H Gy⁻¹) for NIPAM gel dosimeter. The optimized set of imaging exposure parameters was 120 kV_p and 200 mA with the 10 mm slice thickness. Results of the depth dose measurement with gel dosimeter showed a great discrepancy with the actual depth dose data.

Conclusion

According to the current study, NIPAM-based gel dosimetry with X-ray CT imaging needs more technical development and formulation refinement to be used for radiation therapy application.     

Influence of Host Plant Genotype, Presence of a Pathogen, and Coinoculation with Pseudomonas fluorescens Strains on the Rhizosphere Expression of Hydrogen Cyanide- and 2,4-Diacetylphloroglucinol Biosynthetic Genes in P. fluorescens Biocontrol Strain CHA0

The production of hydrogen cyanide (HCN) and 2,4-diacetylphloroglucinol (DAPG) is a major factor in the control of soil-borne diseases by Pseudomonas fluorescens CHA0. We investigated the impact of different biotic factors on the expression of HCN–in comparison to DAPG biosynthetic genes in the rhizosphere. To this end, the influence of plant cultivar, pathogen infection, and coinoculation with other biocontrol strains on the expression of hcnA-lacZ and phlA-lacZ fusion in strain CHA0 was monitored on the roots of bean. Interestingly, all the tested factors influenced the expression of the two biocontrol traits in a similar way. For both genes, we observed a several-fold higher expression in the rhizosphere of cv. Derakhshan compared with cvs. Goli and Naz, although bacterial rhizosphere colonization levels were similar on all cultivars tested. Root infection by Rhizoctonia solani stimulated total phlA and hcnA gene expression in the bean rhizosphere. Coinoculation of strain CHA0 with DAPG-producing P. fluorescens biocontrol strains Pf-68 and Pf-100 did neither result in a substantial alteration of hcnA nor of phlA expression in CHA0 on bean roots. To our best knowledge, this is the first study investigating the impact of biotic factors on HCN production by a bacterial biocontrol strain in the rhizosphere.     

Evaluation of the bioherbicide Myrothecium verrucaria for weed control in tomato (Lycopersicon esculentum)

An isolate of the fungus Myrothecium verrucaria was evaluated for its biocontrol potential against common purslane, horse purslane, spotted spurge, and prostrate spurge, all serious weed pests in commercial tomato fields in the southeastern US. In greenhouse and field tests, M. verrucaria was highly virulent against these weeds when applied as conidial sprays formulated in 0.2% Silwet L-77 surfactant, even in the absence of dew. In field test plots naturally infested with these weeds, seedlings in the two-to-three leaf growth stage treated with M. verrucaria at 2×10⁷ conidia mL^-1 in 0.2% Silwet, exhibited leaf and stem necrosis within 24 h following inoculation, with mortality occurring within 96 h. After 7 days, M. verrucaria had killed 90-95% of both purslane species and 85-95% of both spurge species. Tomatoes that were transplanted into plots treated with M. verrucaria remained healthy and vigorous throughout the growing season. Since M. verrucaria effectively controlled several common weeds under field conditions, this fungus appears to have potential as an effective bioherbicide for pre-plant weed control in production systems with transplanted tomato.     

Synthesis and anticonvulsant activity of new 2-substituted-5- [2-(2-fluorophenoxy)phenyl]-1,3,4-oxadiazoles and 1,2,4-triazoles

A series of new 2-substituted-5-[2-(2-fluorophenoxy)phenyl]-1,3,4-oxadiazoles has been synthesized and screened for their anticonvulsant activities. Compound 3 shows considerable anticonvulsant activity both in PTZ and MES models. It seems that this effect is mediated by benzodiazepine receptors and other unknown mechanism, respectively.     

Intraspecific variation in the venom of the vermivorous cone snail Conus vexillum

A combination of proteomic and biochemical assays was used to examine variations in the venom of Conus vexillum taken from two locations (Hurgada and Sharm El-Shaikh) in the Red Sea, Egypt. Using MALDI/TOF-MS, a remarkable degree of intra-species variation between venom samples from both locations was identified. To evaluate variability in the cytotoxic effects of Conus venom, mice were injected with the same dose from each location. The oxidative stress biomarkers [malondialdehyde (MDA), protein carbonyl content (PCC)], antioxidants [glutathione (GSH), superoxide dismutase (SOD), catalase (CAT)], total antioxidant capacity (TAC) and nitric oxide (NO), were measured 3, 6, 9 and 12 h post venom injection. The venoms induced a significant increase in the levels of PCC, MDA, NO, GSH and CAT. The venoms significantly inhibited the activity of SOD and reduced the TAC. Toxicological data showed that the venom obtained from Hurgada was more potent than that obtained from Sharm El-Shaikh. It can be concluded that: (1) the venom of the same Conus species from different regions is highly diversified (2) the venoms from different locations reflect clear differences in venom potency and (3) the cytotoxic effects of C. vexillum venom can be attributed to its ability to induce oxidative stress.