Oscar García-Barradas

Urine from stressed rats increases immobility in receptor rats forced to swim: Role of 2-heptanone

The present study was aimed to determine whether the urine from donor rats, which were physically stressed (UD-PS) by unavoidable electric footshocks, produces despair in receptor partner rats (RP) in the long-term. For each trial, an RP rat was placed during 10 min once per day for 21 days in a small non-movement-restricting cage impregnated with the urine collected from a UD-PS rat. Control rats, free of stimulation, maintained their locomotion and immobility scores at basal values throughout the 21-day test. After 21 days of stressing experience [F(2,90)=15.22, P<0.0001] locomotion significantly increased in RP rats (r=0.938, P<0.01), whereas in the UD-PS group locomotion decreased (r=-0.606, P<0.05). The RP and UD-PS groups displayed the longest time of immobility [F(2,90)=8.83, P<0.001] in the forced-swim test (RP, r=0.886, P<0.05; UD-PS, r=0.962, P<0.001) compared with the control group (r=-0.307, NS). We conclude that the RP became similarly despaired as the UD-PS group through the action of 2-heptanone, a ketonic compound identified in UD-PS urine by HS-GC/MS techniques. This ketone was found to be increased [F(2,15)=3.50, P<0.05] from the 1st day of unavoidable electric footshocks, and to induce despair, an effect reverted [F(2,21)=16.5, P<0.0001] by imipramine (5.0 mg/kg) in another group of rats.

Bioleaching of gold, copper and nickel from waste cellular phone PCBs and computer goldfinger motherboards by two Aspergillus nigerstrains

In an effort to develop alternate techniques to recover metals from waste electrical and electronic equipment (WEEE), this research evaluated the bioleaching efficiency of gold (Au), copper (Cu) and nickel (Ni) by two strains of Aspergillus niger in the presence of gold-plated finger integrated circuits found in computer motherboards (GFICMs) and cellular phone printed circuit boards (PCBs). These three metals were analyzed for their commercial value and their diverse applications in the industry. Au-bioleaching ranged from 42 to 1% for Aspergillus niger strain MXPE6; with the combination of Aspergillus niger MXPE6 + Aspergillus niger MX7, the Au-bioleaching was 87 and 28% for PCBs and GFICMs, respectively. In contrast, the bioleaching of Cu by Aspergillus niger MXPE6 was 24 and 5%; using the combination of both strains, the values were 0.2 and 29% for PCBs and GFICMs, respectively. Fungal Ni-leaching was only found for PCBs, but with no significant differences among treatments. Improvement of the metal recovery efficiency by means of fungal metabolism is also discussed.

Epicuticular compounds and sexual recognition in the ball-roller scarab, Canthon cyanellus cyanellus

We analyzed the role of cuticular compounds in sexual recognition of the carrion ball‐roller scarab, Canthon cyanellus cyanellus (LeConte) (Coleoptera: Scarabaeidae). Males rolled food balls with freeze‐killed females on them as though the females were alive. Acceptance of female cadavers was low when they were washed with solvents and increased significantly when the solvent extract was reapplied to the cadavers. Acceptance of female cadavers by males was significantly higher than that of male cadavers by females. Male cadavers washed with solvent and impregnated with female cuticular compounds were accepted by males as though they were frozen or living females. Similarly, extracted female cadavers impregnated with male cuticular compounds were accepted by females. These results suggest that C. c. cyanellus males recognize females by their cuticular compounds, whereas females use a combination of cuticular compounds and other unknown cues to recognize males.

Practical and efficient synthesis of (E)-α,β-unsaturated amides bearing (S)-α-methylbenzylamine from 2-phosphonamides via Horner-Wadsworth-Emmons reaction

The highly stereoselective synthesis of (E)-α,β-unsaturated amides bearing (S)-a-methylbenzylamine was achieved from 2-phosphonamides via Homer-Wadsworth-Emmons reaction. The starting phosphonamides are easily prepared in two steps with excellent yields via the standard Arbuzov reaction of trimethylphosphite and α-bromoamides.