Gene and genotypic diversity of Phytophthora cinnamomi in South Africa and Australia revealed by DNA polymorphisms

Phytophthora cinnamomi isolates from South Africa and Australia were compared to assess genetic differentiation between the two populations. These two populations were analysed for levels of phenotypic diversity using random amplified polymorphic DNAs (RAPDs) and gene and genotypic diversity using restriction fragment length polymorphisms (RFLPs). Sixteen RAPD markers from four decanucleotide Operon primers and 34 RFLP alleles from 15 putative loci were used. A few isolates from Papua New Guinea known to posses alleles different from Australian isolates were also included for comparative purposes. South African and Australian P. cinnamomi populations were almost identical with an extremely low level of genetic distance between them (D-m = 0.003). Common features for the two populations include shared alleles, low levels of phenotypic/genotypic diversity, high clonality, and low observed and expected levels of heterozygosity. Furthermore, relatively high levels of genetic differentiation between mating type populations (D-m South Africa = 0.020 and D-m Australia = 0.025 respectively), negative fixation indices, and significant deviations from Hardy-Weinberg equilibrium, all provided evidence for the lack of frequent sexual reproduction in both populations. The data strongly suggest that both the South African and Australian P. cinnamomi populations are introduced.

Preliminary experiences with a single-patient trials service in general practice

Objective: To pilot a single-patient trials (SPTs) service in general practice, designed to improve decision-making about long-term medications for chronic conditions. Design: 12-week within-patient, randomised, double-blind, placebo-controlled, crossover comparison of ibuprofen with paracetamol for osteoarthritis, involving three pairs of two-week treatment periods for each participating patient. Setting and patients: Patients attending an academic general practice with a clinical diagnosis of osteoarthritis, with pain of at least a month's duration severe enough to warrant consideration of long-term non-steroidal anti-inflammatory drug (NSAID) use. Main outcome measures: Pain and stiffness; measures of overall arthritis compared with previous fortnight; preference for NSAID at the end of each two-week treatment period; use of escape analgesia; side effects; and management changes as a result of the SPTs. Results: Eight of 14 patients completed SPTs. One was a clear responder to NSAIDs, five were non-responders, and two were indefinite. Of the five who were using NSAIDs before the SPT, two continued and three ceased using them. Clinically useful information assisted decision-making for all eight participants. Medication management changed for six. Conclusions: Single-patient trials can be successfully implemented in general practice and might be a valuable method for GPs to identify patients who respond to medication for chronic stable conditions such as osteoarthritis, in which individual response to medication is variable.

Experiences with redo aortic valve surgery

Objectives and Methods: Reoperations are an integral part of a cardiac surgeon's practice. We share our experience of 546 reoperations over the last 21 years to January 2000, with the focus directed towards the timing of reoperation, reducing the mortality and morbidity of reoperation and rereplacement aortic valve surgery, and understanding the important risk factors. In addition, the precise technical steps that facilitate careful successful explantation of various devices (allograft, stented and stentless xenografts, and mechanical valves) are detailed. Results: Optimal planned reoperation before deterioration to New York Heart Association Class III/IV levels and before unfavorable cardiac and comorbidity general system failure occurs has produced low mortality and morbidity as compared with first operation results. However, unfavorable delays and late rereferral result in mortality rates of up to 22% for emergency redo AVR for degenerated bioprostheses. Conclusion: Cardiac surgical units have the opportunity to establish a closer patient-surgeon relationship, which favors, when necessary, the optimal timing of reoperation. Knowledge of the more important risk factors and adherence to specific technical steps at explantation of various devices enhances satisfactory reoperation outcomes.

Composition and diversity of Ephemeroptera (Insecta) nymph communities in the middle section of the Jacui River and some tributaries, southern Brazil

The taxonomic composition and diversity of assemblages of Ephemeroptera nymphs of four lotic environments in the central region of State of Rio Grande do Sul, a subtropical area in southern Brazil, were evaluated. Samplings were done monthly, with a Surber sampler, from June 2001 to May 2002, in the Jacui River and three of its tributaries. The total number of nymphs collected in the four sampling sites was 11,007 in five families and 19 genera, of these, 11 are new records for the State. The highest diversity occurred in Point 4 (H` = 2.41) and the lowest in Point 2 (H` = 1.69). Point 4 had the highest environmental stability, conservation of the riparian vegetation and the lowest anthropic impact, while Point 2 presented a large environmental simplification due to a direct anthropic influence ( e. g. domestic sewerage, trampling by cattle). The diversity of nymphs observed in the total area is high, compared to the estimated maximum theoretical diversity; a result of the high evenness and richness recorded. Rarefaction curves, calculated for a sample of 1,018 specimens, showed a similar expectation of richness for the four sampling sites. This result seems to be associated with the overall environmental homogeneity of the region caused by long-term alterations ( land use and deforestation). In summary, higher diversity of Ephemeroptera nymph assemblages seems to be associated with habitat complexity, a good vegetation cover and a lower anthropic influence.

Molecular epidemiology and genetic diversity of hepatitis B virus genotype E in an isolated Afro-Colombian community

Hepatitis B virus (HBV) infection is a significant public health concern with 350 million chronic carriers worldwide. Eight HBV genotypes (A-H) have been described so far. Genotype E (HBV/E) is widely distributed in West Africa and has rarely been found in other continents, except for a few cases in individuals with an African background. In this study, we characterized HBV genotypes in Quibdo, Colombia, by partial S/P gene sequencing, and found, for the first time, HBV/E circulating in nine Afro-Colombian patients who had no recent contact with Africa. The presence of HBV/E in this community as a monophyletic group suggests that it was a result of a recent introduction by some Afro-descendent contact or, alternatively, that the virus came with slaves brought to Colombia. By using sequences with sampling dates, we estimated the substitution rate to be about 3.2x10(-4) substitutions per site per year, which resulted in a time to the most recent common ancestor (TMRCA) of 29 years. In parallel, we also estimated the TMRCA for HBV/E by using two previously estimated substitution rates (7.7x10(-4) and 1.5x10(-5) substitutions per site per year). The TMRCA was around 35 years under the higher rate and 1500 years under the slower rate. In sum, this work reports for the first time the presence of an exclusively African HBV genotype circulating in South America. We also discuss the time of the entry of this virus into America based on different substitution rates estimated for HBV.

Natural Host Relationships and Genetic Diversity of Rodent-Associated Hantaviruses in Southeastern Brazil

Objective: Hantaviruses are rodent-borne RNA viruses that have caused hantavirus cardiopulmonary syndrome in several Brazilian regions. In the present study, geographical distribution, seroprevalence, natural host range, and phylogenetic relations of rodent-associated hantaviruses collected from seven counties of Southeastern Brazil were evaluated. Methods: ELISA, RT-PCR and phylogenetic analysis were used in this study. Results: Antibodies to hantavirus were detected in Bolomys lasiurus, Akodon sp. and Oligoryzomys sp., performing an overall seroprevalence of 5.17%. All seropositive rodents were associated with grasslands or woods surrounded by sugar cane fields. Phylogenetic analysis of partial S- and M-segment sequences showed that viral sequences isolated from B. lasiurus specimens clustered with Araraquara virus. However, a sequence from Akodon sp. shared 100% similarity with Argentinian/Chilean viruses based on the partial S- segment amino acid sequence. Conclusion: These results indicate that there are associations between rodent reservoirs and hantaviruses in some regions of Southeastern Brazil, and suggest the existence of additional hantavirus genetic diversity and host ecology in these areas. Copyright (C) 2008 S. Karger AG, Basel

Molecular diversity of Brazilian strains of porcine circovirus type 2 (PCV-2)

Porcine circovirus 2 (PCV-2) is associated with a broad range of syndromes. In this study, eight pig tissue samples from two Brazilian states were analyzed using six PCR primer pairs amplifying a 1705-bp fragment of the PCV-2 genome. The NJ distance-based method was used for the phylogenetic analysis with the eight field strains herein, 15 GenBank sequences and using PCV-1 as an out-group. This yielded two major clusters (A and B) for this viral species, with the Brazilian strains segregating with European and Asian sequences. Nucleotide identity was 99.7 to 100% among the sequences. This information can be used in further studies of pathogenesis related to PCV-2 in Brazil. (C) 2007 Elsevier Ltd. All rights reserved.

Rabies virus in insectivorous bats: Implications of the diversity of the nucleoprotein and glycoprotein genes for molecular epidemiology

Insectivorous bats are the main reservoirs of rabies virus (RABV) in various regions of the world. The aims of this study were to (a) establish genealogies for RABV strains from different species of Brazilian insectivorous bats based on the nucleoprotein (N) and glycoprotein (G) genes, (b) investigate specific RABV lineages associated with certain genera of bats and (c) identify molecular markers that can distinguish between these lineages. The genealogic analysis of N and G from 57 RABV strains revealed seven genus-specific clusters related to the insectivorous bats Myotis, Eptesicus, Nyctinomops, Molossus, Tadarida, Histiotus and Lasiurus. Molecular markers in the amino acid sequences were identified which were specific to the seven clusters. These results, which constitute a novel finding for this pathogen, show that there are at least seven independent epidemiological rabies cycles maintained by seven genera of insectivorous bats in Brazil. (C) 2010 Elsevier Inc. All rights reserved.

Metastatic lesions in the joint associated with acute inflammatory arthritis after dendritic cell immunotherapy for metastatic melanoma

A 47 year old man undergoing immunotherapy for metastatic melanoma with autologous dendritic cells pulsed with autologous tumour peptide and hepatitis a surface antigen developed acute left ankle arthritis. Gout and acute infection were excluded, and an autoimmune aetiology or occult metastasis were considered. The arthritis initially subsided with indomethacin, but the symptoms recurred 2 months later, and magnetic resonance imaging demonstrated metastatic melanoma of the left talus. Immunohistochemical staining of a cerebral metastatic deposit biopsied 1 week after the onset of arthritis demonstrated T-cell and macrophage infiltration of the tumour. In addition, the patient developed melanoma-specific delayed type hypersensitivity and cytotoxic T-cell responses after vaccination. Thus, the monoarthritis represented an 'appropriate' inflammatory response directed against metastatic melanoma. (C) 2001 Lippincott Williams & Wilkins.

Diversity of Phytophthora clandestina isolated from subterranean clover in southern australia: Analysis of virulence and RAPD profiles

The virulence spectrum of 112 isolates of Phytophthora clandestina collected from 56 sites in four subterranean clover-growing states in southern Australia was determined using differential cultivars of subterranean clover. Five races were detected, with race 0 in all states except New South Wales, race 1 in all states, race 2 only in Victoria, race 3 only in New South Wales, and race 4 in Victoria and Western Australia. The level of genotypic diversity among the different P. clandestina populations was investigated using five RAPD primers. Among 30 bands amplified, only two were polymorphic. This enabled identification of four multilocus RAPD genotypes. Three of the four genotypes occurred in all four states. Races 2 and 3 occurred with RAPD genotypes 1 and 2 only whereas races 0 and 1 occurred in all four multilocus RAPD genotypes. These results indicate that the pathogenicity spectrum of P. clandestina can change rapidly.

Body size and latitudinal gradients in regional diversity of New World birds

Axe latitudinal gradients in regional diversity random or biased with respect to body size? Using data for the New World avifauna, I show that the slope of the increase in regional species richness from the Arctic to the equator is not independent of body size. The increase is steepest among small and medium-sized species, and shallowest among the largest species. This is reflected in latitudinal variation in the shape of frequency distributions of body sizes in regional subsets of the New World avifauna. Because species are added disproportionately in small and medium size classes towards low latitudes, distributions become less widely spread along the body size axis than expected from the number of species. These patterns suggest an interaction between the effects of latitude and body size on species richness, implying that mechanisms which vary with both latitude and body size may be important determinants of high tropical diversity in New World birds.

Identity and genetic diversity of the sorghum ergot pathogen in Australia

Sorghum ergot was first discovered in Australia in 1996. It affects seed production and grain usage in stock feed due to concerns of animal toxicity. Three species of Claviceps are known to cause ergot of sorghum with different epidemiological, animal toxicity, and management implications. Claviceps africana was identified as the causal agent but morphological differences between isolates raised the possibility of more than one species being involved. The major aim of this study was to identify the Claviceps species causing sorghum ergot and to determine the genetic diversity among isolates of the ergot pathogen from Australia and overseas. Symptom development, sequencing of the ITS1 region, and radiolabelled DNA amplification fingerprints (RAF) were used to confirm that ergot of sorghum in Australia is caused by C. africana. The morphology of sphacelia, microconidia, macroconidia, and secondary conidia of all 36 Australian isolates studied matched the description for C. africana and the DNA sequence of the ITS1 region of 2 selected Australian isolates was identical to that of C. africana. Based on RAF analysis of 110 Australian and overseas isolates of Claviceps spp., C. africana isolates could be clearly distinguished (

Mechanisms and diversity of resistance to sorghum midge, Stenodiplosis sorghicola in Sorghum bicolor

Sorghum midge, Stenodiplosis sorghicola (Coquillett) is the most important pest of grain sorghum worldwide, and plant resistance is an important component for the control of this pest. To identify sorghum genotypes with diverse mechanisms of resistance to sorghum midge, we studied oviposition, larval survival, and midge damage in 27 sorghum midge-resistant genotypes, and a susceptible check under greenhouse conditions. Observations were also recorded on floral characteristics and compensation in grain mass. Of the 28 sorghum genotypes tested, 19 showed high levels of antixenosis to oviposition as a component of resistance, and had

Transport safety for older people: A study of their experiences, perceptions and management needs

With evidence of increasing accident risk due to age-related declines in health and cognition affecting driver performance, there is a need for research promoting safe mobility of older people. The present study aimed to identify transport options and licensing issues for a group of older people in an Australian community. Ninety-five participants aged 75 and over were interviewed about their driving status and accident record and tested for cognitive ability. After stratification on cognitive level and driver status (current, ex-driver or non-driver), 30 were selected for further in-depth interviews concerning demographics, licence status and impact of change, travel options available and used, and travel characteristics. Considerable reliance on the motor vehicle as the mode of transport and the decision to cease driving were major quality-of-life issues. There was little evidence of planning and support in making the decision to stop driving. Some differences in transport decisions on the basis of cognitive level were evident; however, people with severely compromised cognitive ability (and, therefore, unable to give informed consent) had been excluded. The study suggested the need for resources to assist older people/carers/health professionals to plan for the transition from driver to non-driver and to manage alternative transport options more effectively

The structural and functional diversity of naturally occurring antimicrobial peptides

Antimicrobial peptides occur in a diverse range of organisms from microorganisms to insects, plants and animals. Although they all have the common function of inhibiting or killing invading microorganisms they achieve this function using an extremely diverse range of structural motifs. Their sizes range from approximately 10-90 amino acids. Most carry an overall positive charge, reflecting a preferred mode of electrostatic interaction with negatively charged microbial membranes. This article describes the structural diversity of a representative set of antimicrobial peptides divided into five structural classes: those with agr-helical structure, those with bgr-sheet structure, those with mixed helical / bgr- sheet structure, those with irregular structure, and those incorporating a macrocyclic structure. There is a significant diversity in both the size and charge of molecules within each of these classes and between the classes. The common feature of their three-dimensional structures is, however, that they have a degree of amphipathic character in which there is separate localisation of hydrophobic regions and positively charged regions. An emerging trend amongst antimicrobial proteins is the discovery of more macrocyclic analogues. Cyclisation appears to impart an additional degree of stability on these molecules and minimizes proteolytic cleavage. In conclusion, there appear to be a number of promising opportunities for the development of novel clinically useful antimicrobial peptides based on knowledge of the structures of naturally occurring antimicrobial molecules.