Soluble and membrane-bound acetylcholinesterases in Mytilus galloprovincialis (Pelecypoda: Filibranchia) from the northern Adriatic sea

Three forms of acetylcholinesterase (AChE) were detected in samples of the bivalve mollusc Mytilus galloprovincialis collected in sites of the Adriatic sea. Apart from the origin of the mussels, two spontaneously soluble (SS) AChE occur in the hemolymph and represent about 80% of total activity, perhaps hydrolyzing metabolism-borne choline esters. These hydrophilic enzymes (forms A and B) copurified by affinity chromatography (procainamide-Sepharose gel) and were separated by sucrose gradient centrifugation. They are, respectively, a globular tetramer (11.0-12.0 S) and a dimer (6.0-7.0 S) of catalytic subunits. The third form, also purified from tissue extracts by the same affinity matrix, proved to be an amphiphilic globular dimer (7.0 S) with a phosphatidylinositol tail giving cell membrane insertion, detergent (Triton X-100, Brij 96) interaction and self-aggregation. Such an AChE is likely functional in cholinergic synapses. All three AChE forms show a good substrate specificity and are inactive on butyrylthiocholine. Studies with inhibitors showed low inhibition by eserine and paraoxon, especially on SS forms, high sensitivity to 1,5-bis(4-allyldimethylammoniumphenyl)-pentan-3-one dibromide (BW284c51) and no inhibition with propoxur and diisopropylfluorophosphate (DFP). The ChE forms in M. galloprovincialis are possibly encoded by different genes. Some kinetic features of these enzymes suggest a genetic polymorphism.     

Larval habitats of sand flies in rural areas of southern Brazil

We report the results of an investigation of natural larval sand fly habitats in the Recanto Marista, Doutor Camargo municipality, Paraná state, Brazil, from May, 2010 to August, 2012. We used Alencar emergence traps (AT), experimental traps (ET), and soil samples incubated in a biochemical oxygen demand incubator. Eight sand flies were collected with ATs. One specimen was collected with an ET and 21 were collected in soil samples. The collected species were Brumptomyia brumpti, Micropygomyia ferreirana, Migonemyia bursiformis, Migonemyia migonei, Nyssomyia neivai, Nyssomyia whitmani, and Pintomyia pessoai. The laval habitats of sand flies were located in the Recanto Marista, especially between tree roots, but the number of adults that emerged in the traps and soil samples was small despite the high density of sand flies that has been recorded in the Recanto Marista.     

Demonstration of glyoxalase II in rat liver mitochondria. Partial purification and occurrence in multiple forms

Glyoxalase II (S-(2-hydroxyacyl)glutathione hydrolase, EC 3.1.2.6), which has been regarded as a cytosolic enzyme, was also found in rat liver mitochondria. The mitochondrial fraction contained about 10-15% of the total glyoxalase II activity in liver. The actual existence of the specific mitochondrial glyoxalase II was verified by showing that all of the activity of the crude mitochondrial pellet was still present in purified mitochondria prepared in a Ficoll gradient. Subfractionation of the mitochondria by digitonin treatment showed that 56% of the activity resided in the mitochondrial matrix and 19% in the intermembrane space. Partial purification of the enzyme (420-fold) was also achieved. Statistically significant differences were found in the substrate specificities of the mitochondrial and the cytosolic glyoxalase II. Electrophoresis and isoelectric focusing of either the crude mitochondrial extract or of the purified mitochondrial glyoxalase II resolved the enzyme activity into five forms with the respective pI values of 8.1, 7.5, 7.0, 6.85 and 6.6. Three of these forms (pI values 7.0-6.6) were exclusively mitochondrial, with no counterpart in the cytosol. The relative molecular mass of the partially purified enzyme, as estimated by Superose 12 gel chromatography, was 21,000. These results give evidence for the presence of mitochondrial glyoxalase II which is different from the cytosolic enzymes in several characteristics.     

Evidence for Locus Heterogeneity in Autosomal Dominant Limb-Girdle Muscular Dystrophy

Limb-girdle muscular dystrophy (LGMD) is a diagnostic classification encompassing a broad group of proximal myopathies. A gene for the dominant form of LGMD (LGMD1A) has recently been localized to a 7-cM region of chromosome 5q between D5S178 and IL9. We studied three additional dominant LGMD families for linkage to these two markers and excluded all from localization to this region, providing evidence for locus heterogeneity within the dominant form of LGMD. Although the patterns of muscle weakness were similar in all families studied, the majority of affected family members in the chromosome 5–linked pedigree have a dysarthric speech pattern, which is not present in any of the five unlinked families. The demonstration of heterogeneity within autosomal dominant LGMD is the first step in attempting to subclassify these families with similar clinical phenotypes on a molecular level.     

Influence of the biomechanical environment on the femoral stem insertion and vibrational behavior: a 3-D finite element study

Biomechanics and Modeling in Mechanobiology - The long-term success of cementless surgery strongly depends on the implant primary stability. The femoral stem initial fixation relies on multiple...     

A case of extra small acrocentric bisatellited chromosome in a non mongoloid child.

A mentally retarded child with an extra small bisatellited acrocentric chromosome is described. The patient exhibited rather unspecific clinical signs such as strabismus, marked facial asymmetry, broad and prominent nasal bridge, hypertelorism, Brushfield's spots, malformed ears with atresia of the external auditory canal on the right side. Giemsa banding (R and G methods) did not allow a clear cytogenetic identification of the extra-chromosome. A tentative interpretation of the cytogenetic aberration as a trisomy of the proximal part of the long arm of chromosome 13 is discussed.     

Isolation of glyoxalase II from bovine liver mitochondria

Bovine liver mitochondria contain about 10% of the total glyoxalase II activity in the homogenate. Electrophoresis and isoelectric focussing of either crude mitochondrial extract or the purified mitochondrial glyoxalase II resolved the enzyme activity into five forms (pl 6.3, 6.7, 7.1, 7.7, and 7.9). Since bovine liver cytosol contains a single form of glyoxalase II (pl 7.5), at least four forms are exclusively mitochondrial with no counterpart in the cytosol. The relative molecular mass of mitochondrial glyoxalase II is about 23-24 kDa, similar to the cytosolic form. The kinetic constants obtained using S-D-lactoyl, S-acetyl-, S-acetoacetyl-, and S-succinyl-glutathione as substrates are similar to those reported for glyoxalase II from rat liver mitochondria. S-D-Lactoyl- and S-acetoacetyl-glutathione are the best substrates. S-Acetylglutathione is the poorest substrate with respect to both Vmax and Km values.     

Gonadoinhibitory effects of Neb-colloostatin and Neb-TMOF on ovarian development in the mealworm, Tenebrio molitor L

The gonadostatic action of the peptides Neb-colloostatin (SIVPLGLPVPIGPIVVGPR) and Neb-TMOF (NPTNLH) from Neobellieria bullata was studied in female mealworm Tenebrio molitor. Both peptides potently inhibit ovarian development and terminal oocyte maturation of mated females during their first reproductive cycle. Injection of 4 mug of Neb-colloostatin or Neb-TMOFNeb-TMOF reduced, at day 4 of the cycle, the size of the terminal oocytes to about half or one third of the normal size in saline-injected controls. In addition, follicular patency was arrested. The injections of Neb-colloostatin and Neb-TMOF also caused a delay to the first ovulation and oviposition as well as a reduction of the number of eggs by about 50% in the first 3 days of the oviposition period. At 4 days after adult emergence, none of the peptides had caused significant changes in protein concentration or composition of the haemolymph. However, both peptides reduced total protein content in ovaries and induced qualitative changes in ovarian protein patterns. Electrophoretic analyses indicated that Neb-colloostatin and Neb-TMOF caused a loss of two proteins (150, 180 kDa) and a drastic reduction of 4 others (39, 43, 47, 130 kDa), which are the most abundant ones in ovaries of control females. On the other hand, they increased the concentration of 2 other polypeptides (65, 70 kDa), which normally occur in insignificant quantities in ovaries. Our results indicate that both peptides have a very similar mode of action despite the differences in their amino acid sequence. They seem to interfere with vitellogenin production by the fat body as well as with vitellogen uptake by the oocytes through modification of patency.     

Lack of extracellular superoxide dismutase (EC-SOD) in the microenvironment impacts radiation-induced changes in neurogenesis

Ionizing irradiation results in significant alterations in hippocampal neurogenesis that are associated with cognitive impairments. Such effects are influenced, in part, by alterations in the microenvironment within which the neurogenic cells exist. One important factor that may affect neurogenesis is oxidative stress, and this study was done to determine if and how the extracellular isoform of superoxide dismutase (SOD3, EC-SOD) mediated radiation-induced alterations in neurogenic cells. Wild-type (WT) and EC-SOD knockout (KO) mice were irradiated with 5 Gy and acute (8-48 h) cellular changes and long-term changes in neurogenesis were quantified. Acute radiation responses were not different between genotypes, suggesting that the absence of EC-SOD did not influence mechanisms responsible for acute cell death after irradiation. On the other hand, the extent of neurogenesis was decreased by 39% in nonirradiated KO mice relative to WT controls. In contrast, while neurogenesis was decreased by nearly 85% in WT mice after irradiation, virtually no reduction in neurogenesis was observed in KO mice. These findings show that after irradiation, an environment lacking EC-SOD is much more permissive in the context of hippocampal neurogenesis. This finding may have a major impact in developing strategies to reduce cognitive impairment after cranial irradiation.     

Insect gonadotropic peptide hormones: some recent developments.

Gonadotropic peptides are a new generation of peptide hormone regulators of insect reproduction. They have been isolated from ovaries, oviducts, or brains of insects. The subject of this paper is insect peptides that exert stimulatory or inhibitory effects on ovarian development and oocyte maturation. On the basis of the literature data and the results of our investigations, the structure and biological properties of different groups of peptides are presented.