134 research outputs found
Allelochemicals from 'Brassica' SPP. (Canola) Residues: Effects on Other Plants and Cereal Fungal Pathogens
'Brassica' spp. have been reported as showing allelopathic activity against other plants and fungi, with both living material and residues shown to be active. Glucosinolate breakdown products have been implicated in many of these allelopathic effects. Canola is a popular crop in Australia, with evidence of increased crop yields and freedom from fungal root diseases in cereals grown following canola. This supports canola's potential as an inhibitor of pathogens. It was hypothesised that allelopathic activity against other plants and fungi is due to compounds produced from canola residues, notably glucosinolate breakdown products. The experiments reported here supported the hypothesis that glucosinolate breakdown products can be phytotoxic to a number of indicator plant species. Indoleacetylnitrile (IAN), indoleacetylmethanol (IAM) and phenylethylamine (PEA) were shown to inhibit germination and early growth, with IAN being the most active. These compounds were found, using HPLC, to be present in canola residue leachates and their concentration estimated
Phylogenetics of the skyhoppers (Kosciuscola) of the Australian Alps : evolutionary and conservation implications
The true biodiversity of Australia's alpine and subalpine endemics is unknown. Genetic studies to date have focused on sub-regions and restricted taxa, but even so, indicate deep divergences across small geographic scales and therefore that the bulk of biodiversity remains to be discovered. We aimed to study the phylogeography of the Australian Alps by focusing on the skyhoppers (Kosciuscola), a genus of five species of flightless grasshoppers whose combined distributions both span the region and are almost exclusively contained within it. Our sampling covered 650 km on the mainland and several sites in Tasmania with total of 260 specimens used to reconstruct a robust phylogeny of Koscisucola. Phylogenies were based on single nucleotide polymorphism data generated from double-digested restriction-associated DNA sequencing. Skyhoppers diverged around 2 million years ago and have since undergone complex diversification seemingly driven by climatic oscillations throughout the Pleistocene. We recovered not 5 but 14 clades indicating the presence of many unknown species. Our results support conspicuous geographic features as genetic breaks; e.g. the Murray Valley, and inconspicuous ones; e.g. between the Bogong High Plains and Mt Hotham. Climate change is progressing quickly in the region and its impact, particularly on snow, could have severe consequences for the skyhoppers' overwinter survival. The true diversity of skyhoppers highlights that biodiversity loss in the Alps as a result of climate change is likely to be far greater than what can be estimated based on current species numbers and that management including small geographical scales is key
Determining effects of areca (betel) nut chewing in a prospective cohort of pregnant women in Madang Province, Papua New Guinea
BACKGROUND: Chewing areca nut (AN), also known as betel nut, is
common in Asia and the South Pacific and the habit has been
linked to a number of serious health problems including oral
cancer. Use of AN in pregnancy has been associated with a
reduction in mean birthweight in some studies, but this
association and the relationship between AN chewing and other
adverse pregnancy outcomes remain poorly understood. METHODS: We
assessed the impact of AN chewing on adverse outcomes including
stillbirth, low birthweight (LBW, <2,500 g) and anaemia at
delivery (haemoglobin <11.0 g/dL) in a longitudinal cohort of
2,700 pregnant women residing in rural lowland Papua New Guinea
(PNG) from November 2009 until February 2013. Chewing habits and
participant characteristics were evaluated at first antenatal
visit and women were followed until delivery. RESULTS: 83.3%
[2249/2700] of pregnant women used AN, and most chewed on a
daily basis (86.2% [1939/2249]. Smoking and alcohol use was
reported by 18.9% (511/2700) and 5.0% (135/2688) of women,
respectively. AN use was not associated with pregnancy loss or
congenital abnormalities amongst women with a known pregnancy
outcome (n = 2215). Analysis of 1769 birthweights did not
demonstrate an association between AN and LBW (chewers: 13.7%
[200/1459] vs. non-chewers: 14.5% [45/310], P = 0.87) or reduced
mean birthweight (2957 g vs. 2966 g; P = 0.76). Women using AN
were more likely to be anaemic (haemoglobin <11 g/dL) at
delivery (75.2% [998/1314] vs. 63.9% [182/285], adjusted odds
ratio [95% CI]: 1.67 [1.27, 2.20], P < 0.001). Chewers more
commonly had male babies than non-chewers (46.1% [670/1455] vs.
39.8% [123/309], P = 0.045). CONCLUSIONS: AN chewing may
contribute to anaemia. Although not associated with other
adverse pregnancy outcome in this cohort gestational AN use
should be discouraged, given the potential adverse effects on
haemoglobin and well-established long-term health risk including
oral cancer. Future research evaluating the potential
association of AN use and anaemia may be warranted. TRIAL
REGISTRATION: ClinicalTrials.gov NCT01136850 (06 April 2010)
Predicting species and community responses to global change using structured expert judgement : an Australian mountain ecosystems case study
Conservation managers are under increasing pressure to make decisions about the allocation of finite resources to protect biodiversity under a changing climate. However, the impacts of climate and global change drivers on species are outpacing our capacity to collect the empirical data necessary to inform these decisions. This is particularly the case in the Australian Alps which has already undergone recent changes in climate and experienced more frequent large-scale bushfires. In lieu of empirical data, we used a structured expert elicitation method (the IDEA protocol) to estimate the abundance and distribution of nine vegetation groups and 89 Australian alpine and subalpine species by the year 2050. Experts predicted that most alpine vegetation communities would decline in extent by 2050; only woodlands and heathlands are predicted to increase in extent. Predicted species-level responses for alpine plants and animals were highly variable and uncertain. In general, alpine plants spanned the range of possible responses, with some expected to increase, decrease or not change in cover. By contrast, almost all animal species are predicted to decline or not change in abundance or elevation range; more species with water-centric life-cycles are expected to decline in abundance than other species. While long-term ecological data will always be the gold-standard in informing the future of biodiversity, the method and outcomes outlined here provide a pragmatic and coherent basis upon which to start informing conservation policy and management in the face of rapid change and paucity of data
Risk factors and pregnancy outcomes associated with placental malaria in a prospective cohort of Papua New Guinean women
BACKGROUND: Plasmodium falciparum in pregnancy results in
substantial poor health outcomes for both mother and child,
particularly in young, primigravid mothers who are at greatest
risk of placental malaria (PM) infection. Complications of PM
include maternal anaemia, low birth weight and preterm delivery,
which contribute to maternal and infant morbidity and mortality
in coastal Papua New Guinea (PNG). METHODS: Placental biopsies
were examined from 1451 pregnant women who were enrolled in a
malaria prevention study at 14-26 weeks gestation. Clinical and
demographic information were collected at first antenatal clinic
visits and women were followed until delivery. Placental
biopsies were collected and examined for PM using histology. The
presence of infected erythrocytes and/or the malaria pigment in
monocytes or fibrin was used to determine the type of placental
infection. RESULTS: Of 1451 placentas examined, PM infection was
detected in 269 (18.5%), of which 54 (3.7%) were acute, 55
(3.8%) chronic, and 160 (11.0%) were past infections. Risk
factors for PM included residing in rural areas (adjusted odds
ratio (AOR) 3.65, 95% CI 1.76-7.51; p </= 0.001), being
primigravid (AOR 2.45, 95% CI 1.26-4.77; p = 0.008) and having
symptomatic malaria during pregnancy (AOR 2.05, 95% CI
1.16-3.62; p = 0.013). After adjustment for covariates, compared
to uninfected women, acute infections (AOR 1.97, 95% CI
0.98-3.95; p = 0.056) were associated with low birth weight
babies, whereas chronic infections were associated with preterm
delivery (AOR 3.92, 95% CI 1.64-9.38; p = 0.002) and anaemia
(AOR 2.22, 95% CI 1.02-4.84; p = 0.045). CONCLUSIONS: Among
pregnant PNG women receiving at least one dose of intermittent
preventive treatment in pregnancy and using insecticide-treated
bed nets, active PM infections were associated with adverse
outcomes. Improved malaria prevention is required to optimize
pregnancy outcomes
Reliability of Rapid Diagnostic Tests in Diagnosing Pregnancy-Associated Malaria in North-Eastern Tanzania.
Accurate diagnosis and prompt treatment of pregnancy-associated malaria (PAM) are key aspects in averting adverse pregnancy outcomes. Microscopy is the gold standard in malaria diagnosis, but it has limited detection and availability. When used appropriately, rapid diagnostic tests (RDTs) could be an ideal diagnostic complement to microscopy, due to their ease of use and adequate sensitivity in detecting even sub-microscopic infections. Polymerase chain reaction (PCR) is even more sensitive, but it is mainly used for research purposes. The accuracy and reliability of RDTs in diagnosing PAM was evaluated using microscopy and PCR. A cohort of pregnant women in north-eastern Tanzania was followed throughout pregnancy for detection of plasmodial infection using venous and placental blood samples evaluated by histidine rich protein 2 (HRP-2) and parasite lactate dehydrogenase (pLDH) based RDTs (Parascreen™) or HRP-2 only (Paracheck Pf® and ParaHIT®f), microscopy and nested Plasmodium species diagnostic PCR. From a cohort of 924 pregnant women who completed the follow up, complete RDT and microscopy data was available for 5,555 blood samples and of these 442 samples were analysed by PCR. Of the 5,555 blood samples, 49 ((proportion and 95% confidence interval) 0.9% [0.7 -1.1]) samples were positive by microscopy and 91 (1.6% [1.3-2.0]) by RDT. Forty-six (50.5% [40.5 - 60.6]) and 45 (49.5% [39.4 - 59.5]) of the RDT positive samples were positive and negative by microscopy, respectively, whereas nineteen (42.2% [29.0 - 56.7]) of the microscopy negative, but RDT positive, samples were positive by PCR. Three (0.05% [0.02 - 0.2]) samples were positive by microscopy but negative by RDT. 351 of the 5,461 samples negative by both RDT and microscopy were tested by PCR and found negative. There was no statistically significant difference between the performances of the different RDTs. Microscopy underestimated the real burden of malaria during pregnancy and RDTs performed better than microscopy in diagnosing PAM. In areas where intermittent preventive treatment during pregnancy may be abandoned due to low and decreasing malaria risk and instead replaced with active case management, screening with RDT is likely to identify most infections in pregnant women and out-performs microscopy as a diagnostic tool
Influence of the number and timing of malaria episodes during pregnancy on prematurity and small-for-gestational-age in an area of low transmission
Association of cord blood methylation fractions at imprinted insulin-like growth factor 2 (IGF2), plasma IGF2, and birth weight
status: publishe
Background matching in the brown shrimp Crangon crangon : adaptive camouflage and behavioural-plasticity
A combination of burrowing behaviour and very efficient background matching makes the brown shrimp Crangon crangon almost invisible to potential predators and preys. This raises questions on how shrimp succeed in concealing themselves in the heterogeneous and dynamic estuarine habitats they inhabit and what type of environmental variables and behavioural factors affect their colour change abilities. Using a series of behavioural experiments, we show that the brown shrimp is capable of repeated fast colour adaptations (20% change in dark pigment cover within one hour) and that its background matching ability is mainly influenced by illumination and sediment colour. Novel insights are provided on the occurrence of non-adaptive (possibly stress) responses to background changes after long-time exposure to a constant background colour or during unfavourable conditions for burying. Shrimp showed high levels of intra- and inter-individual variation, demonstrating a complex balance between behavioural-plasticity and environmental adaptation. As such, the study of crustacean colour changes represents a valuable opportunity to investigate colour adaptations in dynamic habitats and can help us to identify the mayor environmental and behavioural factors influencing the evolution of animal background matching
Malaria and Fetal Growth Alterations in the 3(rd) Trimester of Pregnancy: A Longitudinal Ultrasound Study.
Pregnancy associated malaria is associated with decreased birth weight, but in-utero evaluation of fetal growth alterations is rarely performed. The objective of this study was to investigate malaria induced changes in fetal growth during the 3(rd) trimester using trans-abdominal ultrasound. An observational study of 876 pregnant women (398 primi- and secundigravidae and 478 multigravidae) was conducted in Tanzania. Fetal growth was monitored with ultrasound and screening for malaria was performed regularly. Birth weight and fetal weight were converted to z-scores, and fetal growth evaluated as fetal weight gain from the 26th week of pregnancy. Malaria infection only affected birth weight and fetal growth among primi- and secundigravid women. Forty-eight of the 398 primi- and secundigravid women had malaria during pregnancy causing a reduction in the newborns z-score of -0.50 (95% CI: -0.86, -0.13, P = 0.008, multiple linear regression). Fifty-eight percent (28/48) of the primi- and secundigravidae had malaria in the first half of pregnancy, but an effect on fetal growth was observed in the 3(rd) trimester with an OR of 4.89 for the fetal growth rate belonging to the lowest 25% in the population (95%CI: 2.03-11.79, P<0.001, multiple logistic regression). At an individual level, among the primi- and secundigravidae, 27% experienced alterations of fetal growth immediately after exposure but only for a short interval, 27% only late in pregnancy, 16.2% persistently from exposure until the end of pregnancy, and 29.7% had no alterations of fetal growth. The effect of malaria infections was observed during the 3(rd) trimester, despite infections occurring much earlier in pregnancy, and different mechanisms might operate leading to different patterns of growth alterations. This study highlights the need for protection against malaria throughout pregnancy and the recognition that observed changes in fetal growth might be a consequence of an infection much earlier in pregnancy.\u
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