EGb761 Blocks MPP+-Induced Lipid Peroxidation in Mouse Corpus Striatum

EGb761 has been suggested to be an antioxidant and free radical scavenger. Excess generation of free radicals, leading to lipid peroxidation (LP), has been proposed to play a role in the damage to striatal neurons induced by 1-methyl-4-phenylpyridinium (MPP⁺). We investigated the effects of EGb761 pretreatment on MPP⁺ neurotoxicity. C-57 black mice were pretreated with EGb761 for 17 days at different doses (0.63, 1.25, 2.5, 5 or 10 mg/kg) followed by administration of MPP⁺, (0.18, 0.36 or 0.72 mg/kg). LP was analyzed in corpus striatum at 30 min, 1 h, 2 h and 24 h after MPP⁺ administration. Striatal dopamine content was analyzed by HPLC at the highest EGb761 dose at 2 h and 24 h after MPP⁺ administration. MPP⁺-induced LP was blocked (100%) by EGb761 (10 mg/kg). Pretreatment with EGb761 partially prevented (32%) the dopamine-depleting effect of MPP⁺ at 24 h. These results suggest that supplements of EGb761 may be effective at preventing MPP⁺-induced oxidative stress.     

MPTP Decreases MT-I mRNA In Mouse Striatum

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is a drug that induces parkinsonism in humans and non-human primates. Free radicals are thought to be involved in its mechanism of action. Recently, metallothionein has been proposed to play a role as a scavenger of free radicals. In the present work, we studied the effect of MPTP neurotoxicity on brain metallothionein-I (MT-I) mRNA expression. Male C-57 black mice were treated with MPTP (30 mg/kg, i.p., daily) for 3 or 5 days. All animals were killed by cervical dislocation 7 days after the last MPTP dose. The brains were removed quickly and immediately frozen, and quantitative in situ hybridization was performed using MT-I cDNA probe. MT-I mRNA content in striatum, a region which is known to be highly predisposed and sensitive to MPTP-induced oxidative stress, decreased by 30% (3 days) and 39% (5 days) respectively, after the last MPTP administration. These results suggest that MT-I gene expression is decreased in MPTP neurotoxicity. It is suggested that the reduction of MT, an anti-oxidant and a free radical scavenger, in the striatum by MPTP enables the neurotoxin to exert maximal oxidative damage to the striatum.     

Testicular torsion and its effects on the spermatogenic cycle in the contralateral testis of the rat

The aim of the present study was to evaluate the effects of unilateral testicular torsion on the contralateral testis with respect to the stages of the cycle of the seminiferous epithelium (CSE). Fifty-five male Wistar rats, 60 days old, were used. The animals were divided into 11 groups. Groups 1-5 were subjected to unilateral testicular torsion from 3 to 48 h, followed by detorsion. Groups 6-10 had unilateral orchiectomies after unilateral testicular torsion for 3 to 48 h. Animals constituting group 11 served as the control sham-operated group. All animals were killed after 2 months. The percentage of affected tubules (tubules showing pathological changes) in the contralateral testis was estimated based on the CSE stages. In the torsion/detorsion group, the percentage of affected tubules was significantly greater (58.6%) than in torsion/orchiectomy group (48.0%). Stages VI-XI of the spermatogenic cycle were the most affected when compared with the rest of the stages in each experimental group (P <0.05). These results show that stages VI-XI of the spermatogenic cycle, the stages associated with low antioxidant capacities, are the most sensitive to the effects of testicular torsion on the contralateral testis.     

pep27 and lytA in Vancomycin-Tolerant Pneumococci

Vancomycin therapy failure due to the emergence of tolerance in pneumococci is increasing. The molecular mechanism of tolerance is not clear, but lytA and pep27 are known to be involved. Our aim was to evaluate the expression of both genes in vancomycin-tolerant Streptococcus pneumoniae (VTSP) strains. Eleven VTSP strains from a total of 309 clinical isolates of S. pneumoniae from 1997 to 2006 were classified according to the criteria of Liu and Tomasz. All VTSP strains were evaluated for susceptibility according to CLSI criteria, serotype by the Quellung test, and clonality by PFGE. The expressions of lytA and pep27 were analyzed in different growth phases by RT-PCR with and without vancomycin. Eighty-two percent of VTSP strains showed resistance to penicillin, and 100% were sensitive to vancomycin and cefotaxime. The most frequent serotypes of VTSP strains were 23F (4/11) and 6B (3/11). Clonal relationship was observed in only two strains. No significant changes were observed in pep27 expression in the three phases of growth in VTSP strains with and without vancomycin. Interestingly, pep27 expression in the stationary phase in the non-tolerant reference strain R6 was significantly higher. However, no significant differences in lytA expression were observed between VTSP and R6 strains during the phases of growth analyzed. The absence of changes in pep27 expression in VTSP strains in the stationary phase may be related to their ability to tolerate high antibiotic concentrations, and thus, they survive and remain in the host under the antibiotic selective pressure reflected in therapeutic failure.     

Use of Dactylopius coccus Costa (Hemiptera: Coccoidea) Pigments in the Detection of Larvae and Pupae of Plutella xylostella (L.) (Lepidoptera: Yponomeutidae)

Carmines obtained from the dye of Dactylopius coccus Costa (Hemiptera: Coccoidea) were used for the detection of larvae and pupae of Plutella xylostella (L.) (Lepidoptera: Yponomeutidae) in broccoli inflorescences. Larvae were dyed with carmine II and red cochineal, while the majority of the dyes, with the exception of carmine III and the aqueous extract, were suitable to dye pupae. In the broccoli lumps exposed to the dyes, only the verge of the stems were actually dyed, right in the position where the incision took place, an appropriate characteristic for implementing this technique for commercial use.     

Toluene gas phase biofiltration by Paecilomyces lilacinus and isolation and identification of a hydrophobin protein produced thereof

Paecilomyces lilacinus consumed toluene as the sole carbon source in a gas-phase biofilter packed with perlite obtaining an average elimination capacity of 50 g m(-3) h(-1), a removal efficiency of 53%, and a final biomass of 31.6 mg biomass g dry support(-1). Hydrophobin proteins from the mycelium produced in the biofilter were purified by formic acid extraction and precipitated by electrobubbling, and the molecular weight was found to be 10.6 +/- 0.3 kDa. The peptide mass fingerprinting analysis of the purified hydrophobin by matrix-assisted laser desorption/ionization time-of-flight resulted in the identification of two peptides that presented high homology with sequences of class I hydrophobin proteins from other ascomycetous fungi when compared against the National Center for Biotechnology Information database. The yield of hydrophobin (PLHYD) from P. lilacinus was 1.1 mg PLHYD g biomass(-1). These proteins modified the hydrophobicity of Teflon by lowering the contact angle from 130.1 (+/-2) degrees to 57.0 (+/-5) degrees supporting hot sodium dodecyl sulfate washing. This work is the first report about biodegradation of toluene by the nematophagous fungus P. lilacinus in a gas-phase biofilter and the identification of its hydrophobin protein.     

Zinc-induced survival of Leydig cells in Fischer rats (Rattus norvegicus) treated with cadmium chloride

Zinc is known to prevent cadmium-induced carcinogenesis and Leydig cell destruction in rat testes; however, the mechanism of action is not known, although it has been suggested that pituitary feedback increases the production of luteinizing hormone (LH) in response to low circulating androgen. We therefore examined the biological role of zinc in reducing cadmium toxicity in the Leydig cells of Fischer rats. Two groups of eleven 6-month-old rats were injected subcutaneously with 20 micromol CdCl2/kg weekly for 5 weeks; one of these groups also received 1 mmol/kg zinc acetate weekly for the same 5 weeks. A third group of rats received 1 mmol/kg zinc acetate weekly, and a fourth group was injected with saline weekly for 5 weeks. After 8 months of study, the animals were euthanized by CO2 inhalation. The results indicated that the number of surviving Leydig cells was significantly lower in the cadmium group (7.34% = 0.095 x 10(9)/cm3) than in the cadmium-zinc group (20.85%) or control animals (91.2%). Moreover, the concentrations of serum testosterone and LH were significantly higher in the cadmium group than in any of the other groups. This difference probably was due to the testosterone produced by a small reservoir of surviving Leydig cells and to other endocrine factors. These findings suggest that Fischer rat testis may be a good model system for testing the effects of cadmium and zinc on the production of LH and testosterone and other androgens before spontaneous cancers develop.     

Production and activities of chitinases and hydrophobins from Lecanicillium lecanii

The production of chitinases and hydrophobins from Lecanicillium lecanii was influenced by the cultivation method and type of carbon source. Crude enzyme obtained from solid-substrate culture presented activities of exochitinases (32 and 51 kDa), endochitinases (26 kDa), β-N-acetylhexosaminidases (61, 80, 96 and 111 kDa). Additionally, submerged cultures produced exochitinases (32 and 45 kDa), endochitinases (10 and 26 kDa) and β-N-acetylhexosaminidases (61, 96 and 111 kDa). β-N-acetylhexosaminidases activity determined in solid-substrate culture with added chitin was ca. threefold (7.58 ± 0.57 U mg⁻¹) higher than submerged culture (2.73 + 0.57 U mg⁻¹). Similarly, hydrophobins displayed higher activities in solid-substrate culture (627.3 ± 2 μg protein mL⁻¹) than the submerged one (57.4 ± 4.7 μg protein mL⁻¹). Molecular weight of hydrophobins produced in solid-substrate culture was 7.6 kDa and they displayed surface activity on Teflon.