106 resultados para Caatinga animals - Conservation
Resumo:
The goal of biodiversity conservation has been described as the conservation of diversity at three levels: ecosystem, species and genetic diversity. Developing a representative system of marine protected areas (MPAs) is considered an effective way to achieve this goal in the marine environment. In the absence of detailed information relating to biological distributions there has been increasing use of biodiversity surrogates to determine MPA priorities at regional levels. The development of biodiversity surrogates at fine scales (i.e. habitats) will have an increasingly important role in the identification of sites that will contribute to a representative system of MPAs. This is because it will increase the likelihood that the system will adequately achieve biodiversity objectives by ensuring protection of a greater range of habitats and species. This article provides an explanation of an intertidal shoreline habitat surrogate used to describe 24,216km of Queensland's coastline. The protective status of intertidal habitats was evaluated to assist with designing a representative system of intertidal MPAs. (C) 2002 Elsevier Science Ltd. All rights reserved.
Resumo:
OBJECTIVES The goal of this study was to determine whether the cardiostimulant effects of the endogenous beta(1)-adrenergic receptor (AR) agonist, (-)-norepinephrine are modified by polymorphic (Serine49Glycine [Ser49Gly], Glycine389Arginine [Gly389Arg]) variants of beta(1)-ARs in the nonfailing adult human heart. BACKGROUND Human heart beta(1)-ARs perform a crucial role in mediating the cardiostimulant effects of (-)-norepinephrine. An understanding of the significance of Ser49Gly and Gly389Arg polymorphisms in the human heart is beginning to emerge, but not as yet in adult patients who have coronary artery disease (CAD). METHODS The potency and maximal effects of (-)-norepinephrine at beta(1)-ARs (in the presence of beta(2)-AR blockade with 50 nM ICI 118,551 [erythro-DL-1(7-methylindan-4-yloxy)-3-isopropylamino-butan-2-ol]) for changes in contractile force and shortening of contractile cycle duration were determined in human right atrium in vitro from 87 patients undergoing coronary artery bypass grafting who were taking beta-blockers before surgery. A smaller sample of patients (n = 20) not taking beta-blockers was also investigated. Genotyping for two beta(1)-AR polymorphisms (Ser49Gly and Gly389Arg) was determined from a sample of blood taken at the time of surgery. RESULTS (-)-Norepinephrine caused concentration-dependent increases in contractile force and reductions in time to reach peak force and time to reach 50% relaxation. There were no differences in the potency or maximal effects of (-)-norepinephrine in the right atrium from patients with different Ser49Gly and Gly389Arg polymorphisms. CONCLUSIONS The cardiostimulant effects of (-)-norepinephrine at beta(1)-ARs were conserved across Ser49Gly and Gly389Arg polymorphisms in the right atrium of nonfailing hearts from patients with CAD managed with or without beta-blockers. (C) 2002 by the American College of Cardiology Foundation.
Resumo:
We studied the effect of arsenic exposure on the haem biosynthetic pathway in the rat and humans. Significant increases in protoporphyrin IX, coproporphyrin III, coproporphyrin I were observed in the blood, liver and kidney, and in the urine of rats after a single dose of arsenic. The level of increase was dependent on the arsenic species present. Most of porphyrin concentrations in the tissues increased within 24 hr and urinary excretion elevated within 48 hr. In the human study, we collected urine samples from 113 people who live in Xing Ren of Guizhou Province, a coal-borne arsenicosis endemic area in southwest of PR China and from 30 people who live in Xing Yi (about 80 km southwest of Xing Ren) where arsenicosis is not prevalent. We analyzed the urinary porphyrins using HPLC. Results indicate that all urinary porphyrins were higher in the arsenic exposed group than those in the control group. Women, children and older age people spend much of their time indoors, they had greater increases of urinary arsenic and porphyrins. They were the higher risk groups among the study subjects. A positive correlation between the urinary arsenic levels and porphyrin concentrations demonstrated the effect of arsenic on haem biosynthesis. Significant alteration in the porphyrin excretion profiles of the younger age (
Resumo:
Clearing of native vegetation is a major threat to biodiversity in Australia. In Queensland, clearing has resulted in extensive ecosystem transformation, especially in the more fertile parts of the landscape. In this paper, we examine Queensland, Australian and some overseas evidence of the impact of clearing and related fragmentation effects on terrestrial biota. The geographic locus is the semi-arid regions. although we recognise that coastal regions have been extensively cleared. The evidence reviewed here suggests that the reduction of remnant vegetation to 30% will result in the loss of 25-35% of vertebrate fauna, with the full impact not realised for another 50-100 years, or even longer. Less mobile, habitat specialists and rare species appear to be particularly at risk. We propose three broad principles For effective biodiversity conservation in Queensland: (i) regional native vegetation retention thresholds of 50910: (ii) regional ecosystem thresholds of 30%: and (iii) landscape design and planning principles that protect large remnants, preferably > 2000 ha, as core habitats. Under these retention thresholds. no further clearing would be permitted in the extensively cleared biogeographic regions such as Brigalow Belt and New England Tablelands. Some elements of the biota. however, will require more detailed knowledge and targeted retention and management to ensure their security. The application of resource sustainability and economic criteria outlined elsewhere in this volume should be applied to ensure that the biogeographic regions in the north and west of Queensland that are largely intact continue to provide extensive wildlife habitat.
Resumo:
Habitat instability associated with seasonal crop succession in broad-acre farming systems presents a problem for the conservation and utilisation of beneficial insects in annual field crops. The present paper describes two experiments used to measure the potential of seven plant species to be utilised as winter refuges to support and conserve the predatory bug Pristhesancus plagipennis (Walker). In the first experiment, replicated plots of canola (Brassica napus ), red salvia (Salvia coccinea ), niger (Guizotia abyssinica ), linseed (Linum usitatissimum ), lupins (Lupinus angustifolius ), and lucerne (Medicago falcata ) were planted in a randomized experiment during Autumn 1998. Upon crop establishment, adults and nymphs of P. plagipennis were released into treatment plots and their numbers were assessed, along with those of their potential prey, throughout the ensuing winter months. Post-release sampling suggested that canola and niger retained a proportion of adult P. plagipennis , while niger, lucerne and canola retained some nymphs. The other plant species failed to support P. plagipennis nymphs and adults postrelease. In the second experiment, niger was compared with two lines of sunflower (Helianthus annus ). Both sunflower lines harboured significantly higher (P < 0.05) densities of P. plagipennis nymphs than did niger. The more successful refuge treatments (sunflower, niger and canola) had an abundance of yellow flowers that were attractive to pollinating insects, which served as supplementary prey on which P. plagipennis were observed to feed. Sunflower and niger also supported high densities of the prey insect Creontiades dilutus (Stal) and provided protective leafy canopies which supplied shelter during the winter months. The potential and limitations for using each plant species as a winter refuge to retain P. plagipennis during winter are discussed.
Resumo:
Ichthyosporea is a recently recognized group of morphologically simple eukaryotes, many of which cause disease in aquatic organisms. Ribosomal RNA sequence analyses place Ichthyosporea near the divergence of the animal and fungal lineages, but do not allow resolution of its exact phylogenetic position. Some of the best evidence for a specific grouping of animals and fungi (Opisthokonta) has come from elongation factor 1alpha, not only phylogenetic analysis of sequences but also the presence or absence of short insertions and deletions. We sequenced the EF-1alpha gene from the ichthyosporean parasite Ichthyophonus irregularis and determined its phylogenetic position using neighbor-joining, parsimony and Bayesian methods. We also sequenced EF-1alpha genes from four chytrids to provide broader representation within fungi. Sequence analyses and the presence of a characteristic 12 amino acid insertion strongly indicate that I. irregularis is a member of Opisthokonta, but do not resolve whether I. irregularis is a specific relative of animals or of fungi. However, the EF-1alpha of I. irregularis exhibits a two amino acid deletion heretofore reported only among fungi. (C) 2003 Elsevier Science (USA). All rights reserved.