In vitro evidence for immune evasion activity by human plasmin associated to pathogenic Leptospira interrogans

Leptospirosis is a widespread re-emerging zoonosis of human and veterinary concern. It has been shown that virulent leptospires protect themselves against the host`s innate immune system, a strategy that allows the bacteria to reach immunologically safe environments. Although extensive studies on host pathogen interactions have been performed, little is known on how leptospires deal with host immune attack. In a previous work, we demonstrated the ability of leptospires to bind human plasminogen (PLC), that after treatment with activators, conferred plasmin (PLA) activity on the bacteria surface. In this study, we show that the PLA activity associated to the outer surface of Leptospira could interfere with the host immune attack by conferring some evasion advantage during infection. We demonstrate that PLA-coated leptospires interfere with complement Ob and IgG depositions on the bacterial surface, probably through the degradation of these components, thus diminishing opsonization process. Similar decrease on the deposition was observed when normal and immune sera from patients diagnosed with leptospirosis were employed as a source of IgG. We believe that decreasing opsonization by PLA generation might be an important aspect of the leptospiral immune escape strategy and survival. To our knowledge, this is the first proteolytic activity of plasmin associated-Leptospira related to anti-opsonic properties reported to date. (C) 2011 Elsevier Ltd. All rights reserved.

The public's knowledge of and support for conservation of Australia's Tree-Kangaroos

After providing some brief background on Dendrolagus species in Australia, two consecutive surveys of Brisbane’s residents are used to assess public knowledge of tree-kangaroos and the stated degree of support for their conservation in Australia. The responses of participants in Survey I are based on their pre-survey knowledge of wildlife. The same additional set of participants completed Survey II after being provided with information on all the wildlife species mentioned in Survey I. Changes in the attitudes of respondents and their degree of support for the protection and conservation of Australia’s tree-kangaroos are measured, including changes in their contingent valuations and stated willingness to provide financial support for such conservation. Reasons for wanting to protect tree-kangaroos are specified and analyzed. Furthermore, changes that occur in the relative importance of these reasons with increased knowledge are also examined. Support for the conservation of tree-kangaroos is found to increase with the additional knowledge supplied. Furthermore, support for the conservation of Australia’s less well-known tropical mammals is shown to increase relative to better known mammals (icons) present in temperate areas, such as koalas and red kangaroos with this increased knowledge. Possible implications of the results for government conservation policies in Australia are examined.

Influences on knowledge of wildlife species on patterns of willingness to pay for their conservation

Examines the influence of respondents’ knowledge of wildlife species on their willingness to pay for conservation of the individual species. It does so by using data generated by surveys of 204 individuals who participated in a structured experiment in which their knowledge of a selected set of wildlife species was increased. The species selected were Australian ones, mostly but not entirely, tropical ones. The species were divided into three taxa for the experiment; reptiles, mammals and birds. Each set of species in the taxa included some species expected to be poorly known initially and some anticipated to be well known. Respondents rated their knowledge of each species on a Likert scale, and changes in their average allocation of funds for the conservation of each species were examined as their knowledge increased. Some general relationships are observed.

Fertility and female work force participation in Bangladesh: Causality and cointegration

This paper examines the causal links between fertility and female labor force participation in Bangladesh over the period 1974-2000 by specifying a bivariate and several trivariate models in a vector error correction framework. The three trivariate models alternatively include average age at first marriage for females, per capita GDP and infant mortality rate, which control for the effects of other socio-economic factors on fertility and female labor force participation. All the specified models indicate an inverse long-run relationship between fertility and female labor force participation. While the bivariate model also indicates bidirectional causality, the multivariate models confirm only a unidirectional causality – from labor force participation to fertility. Further, per capita GDP and infant mortality rate appear to Granger-cause both fertility and female labor force participation.

What role does knowledge of wildlife play in providing support for species' conservation?

Conservation of biodiversity is a complex issue. Apart from the creation of nature reserves, there is a plethora of other factors that are part of this complex web. One such factor is the public knowledge of species. Since public funding is imperative for the conservation of species and creation of reserves for them it is important to determine the public’s awareness of species and their knowledge about them. In the absence of such awareness and knowledge, it is possible that the public may misallocate their support. In other words, resources may be provided for species that do not need support urgently. We show how availability of balanced information about species helps the public to make rational decisions and to allocate support (e.g. monetary) to species that need it most. Other implications of a ‘wildlife knowledgeable’ public are also discussed.