The Serine Hydroxymethyltransferase of Plasmodium lophurae*

SYNOPSIS. Plasmodium lophurae serine hydroxymethyltransferase (EC 2.1.2.1) was partially purified and characterized by (NH₄)₂SO₄ fractionation and chromatography on Sephadex G-100. The enzyme, precipitated by 3.0–3.3 m (NH₄)₂SO₄, had a molecular weight of 68,300 as estimated by exclusion chromatography on G-100. The pH optimum of the enzyme was 6.8–7.6 in sodium phosphate-citrate buffer. Citrate stabilized the enzyme during storage in phosphate buffer at 4 C. The K_m was 4.3 × 10^?3m for l -serine and 2.5 × 10^?4m for tetrahydrofolate.     

The diversity and biogeography of koa-finches (Drepanidini: Rhodacanthis), with descriptions of two new species

All known populations of koa-finches, genus Rhodacanthis , became extinct in the Holocene epoch. Two new species are described here from Quaternary fossil sites in the Hawaiian Islands. One new species, from Kauai and Maui, is roughly the size of the historically known greater koa-finch ( R. palmeri ) but differs in having a more robust skull and in bill morphology. The second new species, from Oahu and Maui, is similar in size to the lesser koa-finch ( R. flaviceps ) but closer to R. palmeri in qualitative osteological traits. The two species of koa-finches known historically from the island of Hawaii are distinct in osteology from the fossil koa-finches on the older Hawaiian islands, indicating that at least two of the four known speciation events in the genus took place within approximately the past 500 kyr. However, the similarity of maxillae from Pleistocene and Holocene sites on Oahu suggests that the Oahu population maintained morphological stasis through the climate changes of the late Quaternary. The evidence that speciation occurred on the youngest island in the archipelago suggests that the process of community assembly on newly emergent Hawaiian landscapes was a stimulus to evolutionary diversification in Rhodacanthis .  © 2005 The Linnean Society of London, Zoological Journal of the Linnean Society , 2005, 144 , 527–541.     

Aminopeptidases from Plasmodium falciparum, Plasmodium chabaudi chabaudi and Plasmodium berghei

ABSTRACT. Using fluorogenic substrates and polyacrylamide gels we detected in cell-free extracts of Plasmodium falciparum, Plasmodium chabaudi chabaudi and Plasmodium berghei only a single aminopeptidase. A comparative study of the aminopeptidase activity in each extract revealed that the enzymes have similar specificities and kinetics, a near-neutral pH optima of 7.2 and are moderately thermophilic. Each has an apparent molecular weight of 80,000 ± 10,000, determined by high performance liquid chromatography on a calibrated SW500 column. Whilst the P. c. chabaudi and P. berghei activity co-migrate in native polyacrylamide gels, that of P. falciparum migrates more slowly. The three enzymes can be selectively inhibited by ortho -phenanthroline and are thus metallo-aminopeptidases; however, in contrast to other aminopeptidases the metal co-factor does not appear to be Zn²⁺.     

Determining uptake of 'non-labile' soil cadmium by Thlaspi caerulescens using isotopic dilution techniques

We assessed the ability of several populations of the metal-hyperaccumulator species, Thlaspi caerulescens , to mobilize non-labile cadmium in soils historically contaminated by Pb/Zn mine spoil or sewage sludge. Radio- labile Cd was determined chemically as an ' E -value', [Cd _E ], and biologically as an ' L -value', [Cd _L ]. For comparison, chloride-extractable Cd, [Cd_chlor], was also determined using 1 M CaCl₂ as a single-step soil extractant. Values of [Cd _L ] were measured for six populations of T. caerulescens that varied substantially in their ability to assimilate soil Cd, and a non-accumulator species with a similar growth habit, Lepidium heterophyllum . Seeds were sown in soil spiked with ¹⁰⁹Cd and grown for 9–12 wk in a controlled environment room. Values of [Cd _L ] were determined from the specific activity of ¹⁰⁹Cd and concentration of Cd in the plant leaves. For the six soils studied, [Cd _E ] ranged from 4.9 to 49% of total soil Cd [Cd_T]. Values of [Cd _L ] were, in general, in close agreement with both [Cd _E ] and [Cd_chlor] and substantially less than [Cd_T]. However, [Cd _L ] showed no correlation with the concentration of Cd in plant tissue, [Cd_shoot]. This suggests that, in the soils studied, T. caerulescens did not mobilize non-labile soil Cd by producing root exudates or altering rhizosphere pH. The results imply that there may be significant restrictions to metal bioavailability, even to hyperaccumulator species, in heavily contaminated soils in which a large proportion of the metal may be present in 'non-labile' forms.     

Community mental health care in the Asia‐Pacific region: using current best‐practice models to inform future policy

The reporting of child sexual abuse (CSA) and physician-patient sexual relationships (PPSR) are currently the focus of professional, legal and media attention in several countries. This paper briefly reviews mental health policies on these issues and reports on a WPA survey of them. While the WPA Madrid Declaration permits breaching confidentiality for mandatory reporting of CSA and clearly prohibits PPSR, it is not known how or to what extent these policies are implemented in WPA Member Societies’ countries. It is also not known whether policies or laws exist on these topics nationally or to what extent psychiatrists and the public are aware of them. Representatives of WPA Member Societies were e-mailed a survey about issues pertaining to CSA and PPSR. Fifty-one percent of 109 countries replied. All reporting countries had laws or policies regarding the reporting of CSA, but this was often voluntary (63%) and without protection for reporting psychiatrists either by law (29%) or by Member Societies (27%). A substantial number of psychiatric leaders did not know the law (27%) or their Society’s policy (11%) on these matters. With respect to PPSR, some reporting countries lacked laws or policies about PPSR with current (17%) or past (56%) patients. Fewer than half of responding representatives believed that their Society’s members or the public were well informed about the laws and policies pertaining to CSA or PPSR. There is clearly a wide range of laws, policies and practices about CSA and PPSR in WPA Member Societies’ countries. There is a need in some countries for laws or supplemental policies to facilitate the protection of vulnerable child and adult patients through clear, mandatory reporting policies for CSA and PPSR. Mechanisms to protect and support reporting psychiatrists should also be developed where they do not already exist. There is also a need in some countries to develop strategies to improve the education of psychiatrists, trainees, and the public on these issues.The Asia-Pacific region has close to half of the estimated 450 million people affected by mental illness globally 1.Based on international mental health care benchmarks, many Western health systems have established contemporary health policy and guidelines which include the provision of mental health care in the community. However, the delivery of quality and appropriate community mental health care remains an ongoing challenge for countries of both high and low socio-economic level. Difficulties and obstacles in implementation of comprehensive community service models include inadequate funding, availability of trained mental health workforce, integration with primary care services and community agencies, and collaboration between public and private health systems 2 - 3. As community mental health service system depends on sufficient workforce for service delivery, the critical shortage of adequately trained mental health staff continues to impede the progress of mental health reform.In response to such global trends, many countries in the Asia-Pacific region have begun to establish mental health policy and guidelines to move from institutional care to community mental health services. While these reforms are supported by recommendations from the World Health Organization (WHO) governing bodies, such as the Western Pacific Regional Mental Health Strategy 4, social, economic and cultural factors in Asia-Pacific countries often do not allow ready translation of Western community mental health models of care. Governments and service providers commonly face challenges in the development and implementation of locally appropriate community mental health care and services. Additionally, it would be unrealistic or undesirable to produce rigid recommendations for a singular community mental health care model, due to the diversity across the Asia-Pacific region. Hence, for constructive change to occur in the region, innovative, culturally appropriate and economically sustainable pathways for community treatment models need to be explored, developed and shared. Community mental health service reform appears to be gaining momentum in this region, despite the obstacles. Valuable lessons and inspiration for further development can be gained from both the successes and difficulties in reforming mental health systems and practices in the region.An emerging network of representatives from governments, peak bodies and key organizations is emerging in the Asia-Pacific region to build supportive relationships in order to facilitate the implementation of locally appropriate policy frameworks for community mental health service reform. The network is supported by the Asia-Pacific Community Mental Health Development (APCMHD) project, which involves 14 countries/regions in the Asia-Pacific region. Initiated in collaboration with the WHO Western Pacific Regional Office, the APCMHD project is led by Asia-Australia Mental Health, a consortium of the University of Melbourne Department of Psychiatry and Asialink, and St. Vincent’s Health, which is a part of the WHO Collaborating Centre for Mental Health (Melbourne). The project, which brought many key mental health organizations to work collaboratively, is consistent with the WHO Global Action Programme for Mental Health 5.The project aims are to promote best practice in community mental health care through exchange of knowledge and practical experience in the Asia-Pacific region. The key outcome is the documentation of the current status, strengths and needs of community mental health services in the region, in the hope to translate current understanding into practical changes in the future.     

Attempts to Displace the Indigenous Antibiotic Resistant Gut Flora of Chicken by Feeding Sensitive Strains of Escherichia coli Prior to Slaughter

Attempts to limit the use of antibiotics have not, in general, resulted in the gut flora in farm animals becoming predominantly sensitive. Partial success has been demonstrated, however, by feeding chickens with antibiotic sensitive Escherichia coli known to be good colonizers of the chicken gut. Where feeding was done prior to slaughter a corresponding reduction in carcass contamination by resistant E. coli was observed.     

Costimulation of resting B lymphocytes alters the IL-4-activated IRS2 signaling pathway in a STAT6 independent manner: implications for cell survival and proliferation

INTRODUCTIONThe inappropriate enhancement of lymphocytesurviVal due to a block in programmed cell deathand/or an enhancement of entry into the cell cyclecan contribute to the abnormal expansion of clonesresulting in tumorigenesis or the breakdown of pe-ripheral self-toleranced, 2]. Proper lymphocytehomeostasis is critical for normal immune functionand is maintained by a complex series of cellularinteractions and the action of secreted cytokines.Illterleukin-4 (IL-4), a cytokine produced …     

Multi-scale assessment of macroinvertebrate richness and composition in Mediterranean-climate rivers

1. Similar constraints in distant, but climatically comparable, regions may be expected to yield biotic assemblages with similar attributes. Environmental factors that constrain communities at smaller scales, however, may be different between climatically similar regions. Thus, patterns observed at large scales may differ from those detected at small scales, and international comparisons should be focussed at multiple scales. 2. Mediterranean‐climate regions (MCRs) are characterized by remarkable seasonal variability in precipitation and temperature. Accordingly, rivers in these regions have seasonal and predictable floods and droughts, and temporary reaches are frequent. Present in six geographical regions of the world, MCRs have similar environmental constraints and are ideal for testing intercontinental similarities between macroinvertebrate communities. 3. We examined aquatic macroinvertebrate taxon richness and composition in MCRs at three scales: regional, reach and macrohabitat. At the regional scale, the Mediterranean Basin had the highest taxon richness at family level, and southwestern Australia the lowest. Taxonomic composition showed c. 85% similarity between the northern hemisphere MCRs of California and the Mediterranean Basin, which were followed in similarity by South Africa. The two Australian MCRs (South west and South) showed a similarity to each other of about 70% whereas the Chilean fauna was the most distinct. 4. At the reach scale, taxon richness was not significantly different between permanent and temporary reaches in any MCR, whereas taxonomic composition was significantly different among northern hemisphere MCRs. At the macrohabitat scale, taxon richness was not significantly different between lotic and lentic macrohabitats within any of the MCRs, but differences in macroinvertebrate communities were found between macrohabitats when considering regions. 5. Our results show that the strength of similarity between distant but climatically similar regions is scale‐dependent, being highest at the macrohabitat scale. Although the similarities in richness and composition at the macrohabitat scale are presumed to be universal, the seasonal predictability of drought in MCRs is expected to result in characteristic macroinvertebrate responses at the reach scale. We suggest, however, that regional evolutionary history and environmental characteristics may override this general pattern of a similar response of MCRs at different scales. The Mediterranean Basin and California, having similar historical and environmental condition, thus appeared as the most similar MCRs at all scales.