Structural and functional models for the dinuclear copper active site in catechol oxidases. Synthesis,X-ray crystal structures,magnetic and spectroscopic properties of mu-methoxo-bridged dinuclear copper(II) complexes with N-substituted sulfonamide ligands

Two new mu-methoxo-bridged dinuclear copper(II) complexes with a N-substituted sulfonamide, [Cu(mu-OMe)(L)(NH(3))](2) (1) and [Cu(mu-OMe)(L)(DMSO)](2) (2) [HL, N-2-(4-methylbenzothiazole)benzenesulfonamide], have been prepared and characterized by single-crystal X-ray difraction analyses. Compound 1 crystallizes in the monoclinic space group C(2)/c with a=22.0678(18), b=7.9134(7), c=21.1186(18)A, beta=113.788(4) degrees and Z=8. Compound 2 crystallizes in the monoclinic space group C(2)/c with a=18.0900(10), b=9.5720(10), c=24.2620(10) A, beta=98.7120(10) degrees and Z=8. In both complexes the copper atoms have square-planar environments bridged by two oxygen atoms from methoxide groups. Magnetic susceptibility measurements indicate a very strong antiferromagnetic coupling between the copper(II) ions in both complexes (2J<-1000 cm(-1)). Electronic Paramagnetic Resonance (EPR) spectra of the two complexes both in solid and in solution are silent. 13C NMR spectra of the complexes in solid state have been studied. The complexes have been evaluated as model systems for the catechol oxidase enzyme using 3,5-di-tert-butylcatechol as the test substrate. Complex 2 is slightly more active than complex 1.     

Targeted disruption of the inosine 5'-monophosphate dehydrogenase type I gene in mice

Inosine 5'-monophosphate dehydrogenase (IMPDH) is the critical, rate-limiting enzyme in the de novo biosynthesis pathway for guanine nucleotides. Two separate isoenzymes, designated IMPDH types I and II, contribute to IMPDH activity. An additional pathway salvages guanine through the activity of hypoxanthine-guanine phosphoribosyltransferase (HPRT) to supply the cell with guanine nucleotides. In order to better understand the relative contributions of IMPDH types I and II and HPRT to normal biological function, a mouse deficient in IMPDH type I was generated by standard gene-targeting techniques and bred to mice deficient in HPRT or heterozygous for IMPDH type II. T-cell activation in response to anti-CD3 plus anti-CD28 antibodies was significantly impaired in both single- and double-knockout mice, whereas a more general inhibition of proliferation in response to other T- and B-cell mitogens was observed only in mice deficient in both enzymes. In addition, IMPDH type I(-/-) HPRT(-/0) splenocytes showed reduced interleukin-4 production and impaired cytolytic activity after antibody activation, indicating an important role for guanine salvage in supplementing the de novo synthesis of guanine nucleotides. We conclude that both IMPDH and HPRT activities contribute to normal T-lymphocyte activation and function.     

Identification of Hox Gene Sequences in the Sea Cucumber Holothuria glaberrima Selenka (Holothuroidea: Echinodermata)

The Echinodermata is a unique animal group forming an early branch in the deuterostomes phylogenetic tree. In echinoids and asteroids a single Hox cluster with nine cognates of the vertebrate Hox paralogous groups has been reported, but no data are available from other echinoderm classes. We report here nine Hox-type sequences from the sea cucumber Holothuria glaberrima, a member of the class Holothuroidea. Partial homeodomain sequences were amplified by polymerase chain reaction from genomic DNA and from a regenerating gastrointestinal tract complementary DNA library. Sequence analyses suggest that the holothuroid cluster has at least three genes of the anterior, one of the medial, and five of the posterior groups. This is the first evidence of five posterior sequences in echinoderms. Received July 19, 1999; accepted October 18, 1999.     

Is there an interchromosomal effect in reciprocal translocation carriers? Sperm FISH studies

Chromosome translocations have been known to affect disjunction of chromosomes unrelated to the translocation in the mouse and in Drosophila. However, in humans, an interchromosomal effect in chromosome translocations has not been demonstrated. The availability of techniques that allow the study of nondisjunction in sperm cells has permitted us to evaluate the possibility of an interchromosomal effect in male translocation heterozygotes. In this study, multicolor fluorescence in situ hybridization was used to determine levels of disomy for the clinically relevant chromosomes X, Y, 13, 18, and 21 in 332,858 spermatozoa from nine reciprocal translocation heterozygotes and nine controls with normal karyotypes. The specific translocations studied were as follows: t(10;12)(p26.1;p13.3), t(2;18)(p21;q11.2), t(3;19)(p25;q12), t(5;8)(q33;q13), t(11;22)(q23;q11), t(3;4)(p25;p16), t(8;9) (q24.2;q32), t(10;18)(q24.1;p11.2), and t(4;10)(q33;p12.2). Comparisons of disomy rates between carriers and controls were performed by using the Mann-Whitney test. Our results showed that the rates of sex chromosome hyperhaploidy were similar in controls (0.21%) and in translocation carriers (0.19%). Similarly, the frequencies of disomy for chromosomes 13, 18, and 21 did not differ significantly between controls and carriers (0.05% versus 0.08%, 0.07% versus 0.03%, and 0.14% versus 0.20%, respectively). Sex chromosome nondisjunction was more common than nondisjunction of chromosomes 13 and 18 both in controls (P=0.0057) and in carriers (P=0.0008). Similarly, the rates of chromosome disomy for chromosome 21 were higher than those for chromosomes 13 and 18 in both controls (P=0.0031) and translocation carriers (P=0.0057). In our study, the excess of chromosome 21 disomy versus disomy of the other autosomes was more pronounced in carriers than in controls. Thus, although the difference of disomy 21 between controls and carriers was not statistically significant, it is worthy of attention.     

Prevalence of Abdominal Obesity in Spanish Children and Adolescents. Do We Need Waist Circumference Measurements in Pediatric Practice?

Background

Evidence indicates that central adiposity has increased to a higher degree than general adiposity in children and adolescents in recent decades. However, waist circumference is not a routine measurement in clinical practice.

Objective

This study aimed to determine the prevalence of abdominal obesity based on waist circumferences (WC) and waist to height ratio (WHtR) in Spanish children and adolescents aged 6 to 17 years. Further, the prevalence of abdominal obesity (AO) among normal and overweight individuals was analyzed.

Design

Data were obtained from a study conducted from 1998 to 2000 in a representative national sample of 1521 children and adolescents aged 6 to 17 years (50.0% female) in Spain. WC and WHtR measurements were obtained in addition to BMI. AO was defined as WHtR ≥0.50 (WHtR-AO), sex and age specific WC≥90^th percentile (WC-AO1), and sex and age specific WC cut-off values associated with high trunk fat measured by by dual-energy X-ray absorptiometry (WC-AO2).

Results

IOTF- based overweight and obsity prevalence was 21.5% and 6.6% in children and 17.4% and 5.2% in adolescents, respectively. Abdominal obesity (AO) was defined as WHtR≥0.50 (WHtR-AO), sex- and age-specific WC≥90th percentile (WC-AO1), and sex- and age-specific WC cut-off values associated with high trunk fat measured by dual-energy X-ray absorptiometry (WC-AO2). The respective prevalence of WHtR-AO, WC-AO1, and WC-AO2 was 21.3% (24.6% boys; 17.9% girls), 9.4% (9.1% boys; 9.7% girls), and 26.8% (30.6% boys;22.9% girls) in children and 14.3% (20.0% boys; 8.7% girls), 9.6% (9.8% boys; 9.5% girls), and 21.1% (28.8% boys; 13.7% girls) in adolescents.

Conclusion

The prevalence of AO in Spanish children and adolescents is of concern. The high proportion of AO observed in young patients who are normal weight or overweight indicates a need to include waist circumference measurements in routine clinical practice.     

Measuring selection coefficients below 10(-3): method, questions, and prospects

Measuring fitness with precision is a key issue in evolutionary biology, particularly in studying mutations of small effects. It is usually thought that sampling error and drift prevent precise measurement of very small fitness effects. We circumvented these limits by using a new combined approach to measuring and analyzing fitness. We estimated the mutational fitness effect (MFE) of three independent mini-Tn10 transposon insertion mutations by conducting competition experiments in large populations of Escherichia coli under controlled laboratory conditions. Using flow cytometry to assess genotype frequencies from very large samples alleviated the problem of sampling error, while the effect of drift was controlled by using large populations and massive replication of fitness measures. Furthermore, with a set of four competition experiments between ancestral and mutant genotypes, we were able to decompose fitness measures into four estimated parameters that account for fitness effects of our fluorescent marker (α), the mutation (β), epistasis between the mutation and the marker (γ), and departure from transitivity (τ). Our method allowed us to estimate mean selection coefficients to a precision of 2 × 10(-4). We also found small, but significant, epistatic interactions between the allelic effects of mutations and markers and confirmed that fitness effects were transitive in most cases. Unexpectedly, we also detected variation in measures of s that were significantly bigger than expected due to drift alone, indicating the existence of cryptic variation, even in fully controlled experiments. Overall our results indicate that selection coefficients are best understood as being distributed, representing a limit on the precision with which selection can be measured, even under controlled laboratory conditions.     

The galactose‐binding lectin isolated from Bauhinia bauhinioides Mart seeds inhibits neutrophil rolling and adhesion via primary cytokines

In this study, the amino acid sequence and anti‐inflammatory effect of Bauhinia bauhinioides (BBL) lectin were evaluated. Tandem mass spectrometry revealed that BBL possesses 86 amino acid residues. BBL (1 mg/kg) intravenously injected in rats 30 min prior to inflammatory stimuli inhibited the cellular edema induced by carrageenan in only the second phase (21% – 3 h, 19% – 4 h) and did not alter the osmotic edema induced by dextran. BBL also inhibited carrageenan peritoneal neutrophil migration (51%), leukocyte rolling (58%) and adhesion (68%) and the neutrophil migration induced by TNF‐α (64%). These effects were reversed by the association of BBL with galactose, demonstrating that the carbohydrate‐binding domain is essential for lectin activity. In addition, BBL reduced myeloperoxidase activity (84%) and TNF‐α (68%) and IL1‐β (47%) levels. In conclusion, the present investigation demonstrated that BBL contains highly homologous isolectins, resulting in a total of 86 amino acid residues, and exhibits anti‐inflammatory activity by inhibiting neutrophil migration by reducing TNF‐α and IL1‐β levels via the lectin domain. Copyright © 2015 John Wiley & Sons, Ltd.