Arsenic,Cadmium and Lead Erythrocyte Concentrations in Men with a High,Moderate and Low Level of Physical Training

Biological Trace Element Research - The aim of the present study was to determine changes occurring in the erythrocyte concentrations of arsenic (As), cadmium (Cd) and lead (Pb) in highly trained...     

Cytogenetic characterization of the invasive mussel species Xenostrobus securis Lmk. (Bivalvia: Mytilidae)

The chromosomes of the invasive black-pigmy mussel (Xenostrobus securis (Lmk. 1819)) were analyzed by means of 4',6-diamidino-2-phenylindole (DAPI) / propidium iodide (PI) and chromomycin A3 (CMA) / DAPI fluorescence staining and fluorescent in situ hybridization using major rDNA, 5S rDNA, core histone genes, linker histone genes, and telomeric sequences as probes. The diploid chromosome number in this species is 2n = 30. The karyotype is composed of seven metacentric, one meta/submetacentric, and seven submetacentric chromosome pairs. Telomeric sequences appear at both ends of every single chromosome. Major rDNA clusters appear near the centromeres on chromosome pairs 1 and 3 and are associated with bright CMA fluorescence and dull DAPI fluorescence. This species shows five 5S rDNA clusters close to the centromeres on four chromosome pairs (2, 5, 6, and 8). Three of the four core histone gene clusters map to centromeric positions on chromosome pairs 7, 10, and 13. The fourth core histone gene cluster occupies a terminal position on chromosome pair 8, also bearing a 5S rDNA cluster. The two linker histone gene clusters are close to the centromeres on chromosome pairs 12 and 14. Therefore, the use of these probes allows the unequivocal identification of 11 of the 15 chromosome pairs that compose the karyotype of X. securis.     

ARABIDOPSIS THALIANA HOMEOBOX GENE1 establishes the basal boundaries of shoot organs and controls stem growth

Apical meristems play a central role in plant development. Self-renewing cells in the central region of the shoot meristem replenish the cell population in the peripheral region, where organ primordia emerge in a predictable pattern, and in the underlying rib meristem, where new stem tissue is formed. While much is known about how organ primordia are initiated and their lateral boundaries established, development at the interface between the stem and the meristem or the lateral organs is poorly understood. Here, we show that the BELL-type ARABIDOPSIS THALIANA HOMEOBOX GENE1 (ATH1) is required for proper development of the boundary between the stem and both vegetative and reproductive organs and that this role partially overlaps with that of CUP-SHAPED COTYLEDON genes. During the vegetative phase, ATH1 also functions redundantly with light-activated genes to inhibit growth of the region below the shoot meristem. Consistent with a role in inhibiting stem growth, ATH1 is downregulated at the start of inflorescence development and ectopic ATH1 expression prevents growth of the inflorescence stem by reducing cell proliferation. Thus, ATH1 modulates growth at the interface between the stem, meristem, and organ primordia and contributes to the compressed vegetative habit of Arabidopsis thaliana.     

Antioxidant activity and metabolite profile of quercetin in vitamin-E-depleted rats

Dietary antioxidants interact in a dynamic fashion, including recycling and sparing one another, to decrease oxidative stress. Limited information is available regarding the interrelationships in vivo between quercetin and vitamin E. We investigated the antioxidant activity and metabolism of quercetin (Q) in 65 F-344 rats (n=13 per group) randomly assigned to the following vitamin E (VE)-replete and -deficient diets: (a) VE replete (30 mg alpha-tocopherol acetate/kg diet) control ad libitum (C-AL), (b) VE replete pair fed (C-PF), (c) VE replete+5.0 g Q/kg diet (R-VE+5Q), (d) VE deplete (<1 mg/kg total tocopherols)+5.0 g Q/kg diet (D-VE+5Q) and (e) D-VE. After 12 weeks, blood and tissue were collected for measurement of plasma vitamin E, quercetin and its metabolites, serum pyruvate kinase (PK), plasma protein carbonyls, malondialdehyde (MDA) and oxygen radical absorbance capacity. D-VE diets decreased serum alpha-tocopherol and increased PK activity in a time-dependent manner. The D-VE diet increased plasma protein carbonyls but did not affect MDA. Dietary quercetin supplementation increased quercetin and its metabolites in plasma and liver but did not affect D-VE-induced changes in plasma alpha-tocopherol, PK or protein carbonyls. Plasma isorhamnetin and its disposition in muscle were enhanced by the D-VE diet, as compared to the R-VE diet. Conversely, tamarixetin disposition in muscle was decreased by the D-VE diet. Thus, quercetin did not slow vitamin E decline in vivo; neither did it provide antioxidant activity in vitamin-E-depleted rats. However, vitamin E status appears to enhance the distribution of isorhamnetin into the circulation and its disposition in muscle.     

Selective action of acetogenin mitochondrial complex I inhibitors

Five annonaceous acetogenins, rolliniastatin-1 [structure: see text], rolliniastatin-2 [structure: see text], laherradurin [structure: see text], squamocin [structure: see text], annonacin [structure: see text], and rotenone as a reference, differing in their NADH oxidase inhibition activity, have been evaluated for antifeedant, insecticidal, trypanocidal and cytotoxic effects on insect, mammalian and tumor cells. All the test compounds were toxic to Leptinotarsa decemlineata, demonstrated selective cytotoxicity to insect Sf9 cells and a panel of tumor cell lines with the multidrug-resistant SW480 (P-glycoprotein+, Pgp+) being the most sensitive one. Compounds [structure: see text] and rotenone had post-ingestive effects against Spodoptera littoralis larvae while [structure: see text] and rotenone were active against Trypanosoma cruzi. Based on their biochemical properties (inhibition of the mitochondrial NADH oxidase activity), the in vivo effects of these compounds on S. littoralis and their cytotoxic effects on Sf9 and tumor cells were more predictable than their effect on T. cruzi and mammalian cells.     

Chemical Analysis of the Lamella Walls of Agaricus bisporus Fruit Bodies

Purified lamella wall fragments of Agaricus bisporus fruit bodies were analyzed and shown to consist of neutral sugars (46.5%), hexosamines (31.7%), proteins (9.5%), some lipid material (10.0%), and ash (1.4%). The cell walls were fractionated on the basis of their polysaccharide solubility in water and alkaline solutions. The isolated fractions, using methylation analysis, exhibited striking chemical structural differences compared with the same fractions obtained from the corresponding vegetative cells and fruit bodies (stipe and pileus) walls. The structural differences detected in the wall seem to correspond to the ultimate differentiation of the mycelium inside the fruit body of A. bisporus. Received: 30 November 1998 / Accepted: 29 January 1999     

Analysis of the gyrA gene of clinical Yersinia ruckeri isolates with reduced susceptibility to quinolones

Antimicrobial susceptibility of seven clinical strains of Yersinia ruckeri representative of those isolated between 1994 and 2002 from a fish farm with endemic enteric redmouth disease was studied. All isolates displayed indistinguishable pulsed-field gel electrophoresis restriction patterns, indicating that they represented a single strain. However, considering both inhibition zone diameters (IZD) and MICs, the isolates recovered in 2001-2002 formed a separate cluster with lower levels of susceptibility to all the quinolones tested, especially nalidixic acid (NA) and oxolinic acid (OA), compared with the isolates recovered between 1994 and 1998. Analysis of the PCR product of the quinolone resistance-determining region of the gyrA gene from clinical isolates of Y. ruckeri with reduced susceptibility to OA and NA revealed a single amino acid substitution, Ser-83 to Arg-83 (Escherichia coli numbering). Identical substitution was observed in induced OA-resistant mutant strains, which displayed IZD and MICs of quinolones similar to those of the clinical isolates of Y. ruckeri with reduced susceptibility to these antimicrobial agents. These data indicate in that for Y. ruckeri, the substitution of Ser by Arg at position 83 of the gyrA gene is associated with reduced susceptibility to quinolones.     

Centennial olive trees as a reservoir of genetic diversity

Background and Aims

Genetic characterization and phylogenetic analysis of the oldest trees could be a powerful tool both for germplasm collection and for understanding the earliest origins of clonally propagated fruit crops. The olive tree (Olea europaea L.) is a suitable model to study the origin of cultivars due to its long lifespan, resulting in the existence of both centennial and millennial trees across the Mediterranean Basin.

Methods

The genetic identity and diversity as well as the phylogenetic relationships among the oldest wild and cultivated olives of southern Spain were evaluated by analysing simple sequence repeat markers. Samples from both the canopy and the roots of each tree were analysed to distinguish which trees were self-rooted and which were grafted. The ancient olives were also put into chronological order to infer the antiquity of traditional olive cultivars.

Key Results

Only 9·6 % out of 104 a priori cultivated ancient genotypes matched current olive cultivars. The percentage of unidentified genotypes was higher among the oldest olives, which could be because they belong to ancient unknown cultivars or because of possible intra-cultivar variability. Comparing the observed patterns of genetic variation made it possible to distinguish which trees were grafted onto putative wild olives.

Conclusions

This study of ancient olives has been fruitful both for germplasm collection and for enlarging our knowledge about olive domestication. The findings suggest that grafting pre-existing wild olives with olive cultivars was linked to the beginnings of olive growing. Additionally, the low number of genotypes identified in current cultivars points out that the ancient olives from southern Spain constitute a priceless reservoir of genetic diversity.     

The M2-type isoenzyme of pyruvate kinase phosphorylates prothymosin α in proliferating lymphocytes

Prothymosin α (ProTα) is a multifunctional protein that, in mammalian cells, is involved in nuclear metabolism through its interaction with histones and that also has a cytosolic role as an apoptotic inhibitor. ProTα is phosphorylated by a protein kinase (ProTαK), the activity of which is dependent on phosphorylation. ProTα phosphorylation also correlates with cell proliferation. Mass spectrometric analysis of ProTαK purified from human tumor lymphocytes (NC37 cells) enabled us to identify this enzyme as the M2-type isoenzyme of pyruvate kinase. A study on the relationship between ProTαK activity and pyruvate kinase isoforms in NC37 cells and in other cell types confirmed that the M2 isoform is the enzyme responsible for ProTαK activity in proliferating cells. Yet, about 10% of the cellular pool of the M2 isoform shows specific affinity for ProTα and is responsible for ProTαK activity. This pool of M2 protein possesses no observable pyruvate kinase activity and changes its responses to various effectors of pyruvate kinase activity; however, these responses to PK effectors are maintained by the main cellular fraction containing the M2 isoform. Acquisition of ProTαK activity by M2 seems to be due to the phosphorylation of serine and threonine residues, which, besides being essential for its catalytic activity, induces a trimeric association of ProTαK. This association can be shifted to a tetrameric form by fructose 1, 6-bisphosphate, which results in a decrease in ProTαK activity.     

Some significant differences in wall chemistry among four commercial Agaricus bisporus strains

Significant differences in gross wall chemical composition were detected in four commercial Agaricus bisporus strains. All were grown under the same conditions and their walls prepared by a mild method of breakage. A more detailed analysis of the wall fractions, isolated by means of their distinct solubilities, also showed striking structural differences among the four strains studied. The detected differences, not only in the overall composition of the wall but also in the polysaccharide structure, could assist in the characterization of strains and/or varieties of the commercial basidiomycete A. bisporus.