Foliar temperature tolerance of temperate and tropical evergreen rain forest trees of Australia

Australian rain forests extend from tropical climates in the north to temperate climates in the south, providing an opportunity to investigate physiological responses to temperature of both temperate and tropical species within the same forest type. Eight, rain forest canopy tree species were selected to cover the 33 degrees latitudinal range of rain forests in eastern Australia. Temperature tolerance was measured in 6-year-old plants grown in a common environment, by exposing leaves to a series of high temperatures during late summer and a series of freezing temperatures during midwinter. Damage was evaluated based on chlorophyll fluorescence measurements made 2 h after exposure and by visual assessment of leaf damage made a week after exposure. Leaves of the tropical species were more heat tolerant and less frost tolerant than leaves of the temperate species, which is consistent with their climate distributions. In contrast, the temperature tolerance of the photosynthetic apparatus was unrelated to climate in a species' native habitat. However, the tropical species underwent significant photoinhibition during winter. All species maintained the integrity of the photosynthetic apparatus and avoided tissue damage over a similar span of temperatures (about 60 degrees C), reflecting the similar annual temperature ranges in Australia's temperate and tropical rain forests. Chlorophyll fluorescence measurements and visual assessment of leaf damage provided different estimates of the absolute and relative temperature tolerances of the species, thus emphasizing the importance of a direct assessment of tissue damage for determining a species' temperature tolerance.

Prejudice and schizophrenia: a review of the 'mental illness is an illness like any other' approach

OBJECTIVE

Many anti-stigma programmes use the 'mental illness is an illness like any other' approach. This review evaluates the effectiveness of this approach in relation to schizophrenia.

METHOD

The academic literature was searched, via PsycINFO and MEDLINE, to identify peer-reviewed studies addressing whether public espousal of a biogenetic paradigm has increased over time, and whether biogenetic causal beliefs and diagnostic labelling are associated with less negative attitudes.

RESULTS

The public, internationally, continues to prefer psychosocial to biogenetic explanations and treatments for schizophrenia. Biogenetic causal theories and diagnostic labelling as 'illness', are both positively related to perceptions of dangerousness and unpredictability, and to fear and desire for social distance.

CONCLUSION

An evidence-based approach to reducing discrimination would seek a range of alternatives to the 'mental illness is an illness like any other' approach, based on enhanced understanding, from multi-disciplinary research, of the causes of prejudice.

The paradoxical effects of nutrient ratios and supply rates on an outbreaking insect herbivore, the Australian plague locust

1. The Australian plague locust, Chortoicetes terminifera, develops following rainfall in an environment dominated by two host plants, the annual Dactyloctenium radulans and the perennial Astrebla lappacea. This simple system provides an ideal opportunity to explore the relationship between plant quality, individual herbivore performance and population responses. 2. We compared the two grasses chemically and structurally, and the behavioural, physiological and developmental responses of locust nymphs to these diets. 3. The grasses appeared to be of similar nutritional quality in terms of their chemical composition, although they differed in their physical properties. Early instar nymphs performed equally well on both grasses. However, older nymphs consuming D. radulans developed faster, survived better and attained a higher body weight compared with those consuming A. lappacea. 4. The differences in performance by the older nymphs related to the rate and ratio of supply of carbohydrate and protein from the two grasses, with less carbohydrate being assimilated from A. lappacea than D. radulans per unit of protein assimilated. Experiments showed that these differences arose as a direct result of the physical barrier to nutrient extraction provided by cell walls and indirectly through the amount of water contained within each cell. Paradoxically, nitrogen did not limit performance in the traditional sense through shortage,but rather its relative excess in A. lappacea appeared to impede intake and assimilation of adequate carbohydrate. 5. As a consequence, we predict that the length of time D. radulans remains available following rainfall will influence plaguing dynamics, although not for the reasons previously thought. 6. The results highlight the need to consider nutrient balance and actual rates of supply (rather than simply measuring the chemical composition of the plant) when attempting to understand herbivore nutritional ecology.

Changes in basal cell mitosis and transepidermal water loss in skin cultures treated with vitamins C and E

Three variants of the living skin equivalent cultures were compared in order to determine the most suitable to grow human differentiated epidermis to test beneficial properties of nutrients. Criteria of culture quality were mitotic index and transepidermal water loss (TEWL) assayed by means of a ServoMed Evaporimeter EP-2TM (ServoMed, Kinna, Sweden). Standards were donor skin mean mitotic index 11.1% and TEWL of living subjects mean 6.4 g/m(2)/h. Cultures (i) in 5% serum, 10 ng/ml of epidermal growth factor (EGF) at 37 degrees C and 95% relative humidity (RH); mitotic index on day 14, 19.2%, but on day 21, 1.8% and TEWL 9.5 g/m(2)/h on day 18. (ii) In 1% serum, no EGF, 33 degrees C and 95% RH, mitotic index on day 21, 9.1% and TEWL, 9.5% on day 18. (iii) Culture in same medium, 33 degrees C and 60% RH, mitotic index on day 28, 9.5% and TEWL 6.1 g/m(2)/h on day 18 as in vivo. Incubation in 60% RH was achieved using a novel chamber and dishes exposing only the corneum, sealing the medium. Vitamins C and E were used as model test nutrients. Culture conditions were 1% serum, no EGF at 33 degrees C and 95% RH. Vitamin C at 142 and 284 microM increased the mitotic index after 10- and 15-day treatment, but at 586 microM it was weakly toxic. Vitamin E at 20 and 40 microM did not. Both vitamins reduced TEWL providing functional data in support of previous reports on barrier properties. These are functional biomarkers of skin benefit relevant to skin in vivo.

Childhood trauma, psychosis and schizophrenia: a literature review with theoretical and clinical implications

OBJECTIVE

To review the research addressing the relationship of childhood trauma to psychosis and schizophrenia, and to discuss the theoretical and clinical implications.

METHOD

Relevant studies and previous review papers were identified via computer literature searches.

RESULTS

Symptoms considered indicative of psychosis and schizophrenia, particularly hallucinations, are at least as strongly related to childhood abuse and neglect as many other mental health problems. Recent large-scale general population studies indicate the relationship is a causal one, with a dose-effect.

CONCLUSION

Several psychological and biological mechanisms by which childhood trauma increases risk for psychosis merit attention. Integration of these different levels of analysis may stimulate a more genuinely integrated bio-psycho-social model of psychosis than currently prevails. Clinical implications include the need for staff training in asking about abuse and the need to offer appropriate psychosocial treatments to patients who have been abused or neglected as children. Prevention issues are also identified.

Using the Internet? The experiences of parents of disabled children

BACKGROUND

Research has offered consistent evidence that the provision of crucial information to parents of disabled children, at a time when they need it and in a form that they can use, is an intractable problem. This makes it important to develop new and effective approaches to information presentation, distribution and delivery. The Internet has been put forward as a medium through which families' needs for information and services can be met. This paper looks at parents of disabled children's experience of using it.

METHODS

A cross-sectional survey of 3014 adult carers, of which 788 were carers of disabled children aged 0-17. Data were collected using a postal questionnaire.

RESULTS

A high proportion (75%) had previously used the Internet. Of these, 63% were frequent users and 91% were using it at home. Popular uses were emailing, obtaining information about caring, ordering equipment and shopping online. Despite positive benefits, users experienced problems relating to technical issues and equipment and system design. Lack of time owing to caring and other circumstances was an issue for over half of all users. Never users were more likely to be living in rented accommodation, be unemployed and not have a PC at home. Reasons for not using the Internet included lack of access to equipment, cost and lack of skill.

CONCLUSIONS

For some parents the Internet is a viable and flexible medium for accessing useful information and services. However, caution about the extent to which it becomes the primary means for delivering information is needed. Technical problems and lack of time can make it difficult to search for complex information. The 'digital divide' between users and non-users makes it crucial that issues of cost, lack of equipment and skill be addressed. Information needs to be made available in other forms to ensure that those who cannot or do not wish to use the Internet are not socially excluded.

Early computational processing in binocular vision and depth perception

Stereoscopic depth perception is a fascinating ability in its own right and also a useful model of perception. In recent years, considerable progress has been made in understanding the early cortical circuitry underlying this ability. Inputs from left and right eyes are first combined in primary visual cortex (V1), where many cells are tuned for binocular disparity. Although the observation of disparity tuning in V1, combined with psychophysical evidence that stereopsis must occur early in visual processing, led to initial suggestions that V1 was the neural correlate of stereoscopic depth perception, more recent work indicates that this must occur in higher visual areas. The firing of cells in V1 appears to depend relatively simply on the visual stimuli within local receptive fields in each retina, whereas the perception of depth reflects global properties of the stimulus. However, V1 neurons appear to be specialized in a number of respects to encode ecologically relevant binocular disparities. This suggests that they carry out essential pre-processing underlying stereoscopic depth perception in higher areas. This article reviews recent progress in developing accurate models of the computations carried out by these neurons. We seem close to achieving a mathematical description of the initial stages of the brain's stereo algorithm. This is important in itself--for instance, it may enable improved stereopsis in computer vision--and paves the way for a full understanding of how depth perception arises.

A double-blind, placebo-controlled trial of fluvoxamine in binge eating disorder: a high placebo response

Twenty subjects with binge eating disorder were randomly assigned to flexible-dose fluvoxamine or placebo for 12 weeks. A significant reduction in binge frequency, Beck Depression Inventory scores and the eating concern, shape concern and weight concern subscales of the Eating Disorder Examination were noted for both fluvoxamine (n = 9) and placebo (n = 11) groups. There were no significant differences between fluvoxamine and placebo for any treatment outcome variables. The findings from this small trial contribute to the inconsistent results of antidepressant studies in binge eating disorder.

Do temperate rainforest trees have a greater ability to acclimate to changing temperatures than tropical rainforest trees?

•  Photosynthetic responses to acclimation temperature were investigated in seedlings of eight Australian rainforest tree species. Australian rainforests extend over 33° of latitude, providing an opportunity to compare temperature responses of temperate and tropical species. •  Net photosynthesis was measured in leaves developed under a constant (22°C : 14°C) or fluctuating (17°C : 9°C-27°C : 19°C) day/night temperature regime. These leaves were then subjected to a series of constant temperature regimes and net photosynthesis was measured 14 d after acclimation to each new regime. •  Acclimation potential was not affected by the contrasting temperature regimes. The temperate species showed at least 80% of maximum net photosynthesis over a larger span of acclimation temperature than the tropical species. •  The lack of an effect of the contrasting temperature regimes on acclimation potential may reflect either that adjustments were unnecessary for temperate species, which already have broad photosynthetic responses to temperature, and tropical species were incapable of adjustments, or that in general species respond to the mean temperature regime and not to the amount of fluctuation in the regime. The higher acclimation potential shown by the temperate species is consistent with the larger seasonal and day-to-day variation in temperature of the temperate climate compared with the tropical climate.

Kangaroo harvesters: fertilising the rangelands

Offcuts from harvested red kangaroo (Macropus rufus), comprising the head, stomach, entrails, legs and joey (females only) and sometimes the tail remain near the point of harvest. Offcut weights of males averaged 11.46 kg and comprised 26% of the total body mass, whilst average female offcuts weighed 6.69 kg and comprised 31% of total body mass. There was a strong correlation between carcass and offcut mass for both sexes. Offcuts from 27 kangaroos were randomly exposed to three different assemblages of vertebrate scavengers. Soil nitrogen and organic carbon concentrations increased significantly following the addition of offcuts but there was no significant change in soil potassium concentrations or pH. Decomposition and dispersal of offcuts was enhanced by accessibility to different scavenging guilds. The contribution of the kangaroo industry to soil nutrient retention and cycling contrasts with the depletion of nutrients through the export of domestic livestock from the Australian rangelands.

Identification of AFLP and microsatellite markers linked with an aluminium tolerance gene in barley ( Hordeum vulgare L.)

Barley is the most sensitive among the cereals to aluminium (Al) stress and breeding for more tolerant cultivars is a priority. To enhance selection efficiency for Al tolerance in barley, PCR-based AFLP and microsatellite markers linked to a locus conferring tolerance to aluminium were identified. The study used F(2) progeny derived from a single cross between Yambla (moderately tolerant of Al) and WB229 (tolerant of Al) and developed hydroponic pulse-recovery screening methods to assess tolerance of phenotypes based on root growth. The segregation ratios of tolerant and sensitive genotypes and F(3) progeny testing suggest that a single major gene controlled Al tolerance ( Alt). In order to determine the chromosomal location of the Alt gene, we used the AFLP technique coupled with bulk segregant analysis. We evaluated tolerant and sensitive bulks using 30 combinations of EcoRI/ MseI primers, and 12 of these permitted differentiation of the sensitive and tolerant bulks. More than 1,000 amplified fragments were obtained, and 98 polymorphic bands were scored. AFLP analysis of wheat-barley chromosome addition lines indicated that the Alt gene was located on barley chromosome 4H. Four chromosome 4H-specific microsatellite markers (Bmac310, Bmag353, HVM68 and HVMCABG) were tightly linked to Alt. The large allelic variation detected with microsatellite marker Bmag353 allowed us to implement this marker for routine marker-assisted selection for Al tolerance, and 396 plants could be screened on a single gel.

Decolorization of textile dyes by laccases from a newly isolated strain of Trametes modesta

Four ligninolytic fungi, Trametes modesta, Trametes hirsuta, Trametes versicolor and Sclerotium rolfsii, were compared for their ability to produce laccases. The fungal laccases were screened for their ability to decolorize eight synthetic dyes (anthraquinone, azo, indigo and triarylmethane). The decolorization rate depended both on the source of the enzyme preparation and on the structure of the dye. Based on laccase production and dye decolorizing ability, T. modesta was selected for further studies. All the tested dyes were decolorized by the T. modesta laccase most efficiently under acid conditions (pH 3-6) but the optimum pH for decolorization of the individual dye varied. The decolorization rate of this laccase increased with the rise in temperature to 50-60 degrees C. The decolorization efficiency of T. modesta laccase was improved remarkably in the presence of mediators like 1-hydroxybenzotriazole and 2-methoxyphenothiazine.

'A sort of destiny': the multi-jurisdictional response to sewage pollution in the Great Lakes, 1900-1930

At the turn of the twentieth century, water pollution was the primary vector spreading waterborne disease and a public health issue. In the Great Lakes basin, unprecedentedly high mortality from typhoid fever prompted a conference of federal and provincial public health officials in 1910. Three related initiatives resulted: the provincial government amended the Public Health Act in 1912; federal legislators attempted to develop national pollution control legislation between 1912 and 1915; the International Joint Commission investigated cross boundary pollution in 1912 and recommended a convention to control it. Of the three initiatives, only the provincial Public Health Act amendments were carried to fruition. By 1915, the almost universal adoption of chlorine treatment for municipal water supplies effectively controlled waterborne disease and there was no longer a perceived need for further action.

The crystal structure of human phosphoglucose isomerase at 1.6 Å resolution: implications for catalytic mechanism, cytokine activity and haemolytic anaemia

Phosphoglucose isomerase (PGI) is a multifunctional protein, which, inside the cell, functions as a housekeeping enzyme of glycolysis and gluconeogenesis and, outside the cell, exerts wholly unrelated cytokine properties. We have determined the structure of human PGI to a resolution of 1.6 A using X-ray crystallography. The structure is highly similar to other PGIs, especially the architecture of the active site. Fortuitous binding of a sulphate molecule from the crystallisation solution has facilitated an accurate description of the substrate phosphate-binding site. Comparison with both native and inhibitor-bound rabbit PGI structures shows that two loops move closer to the active site upon binding inhibitor. Interestingly, the human structure most closely resembles the inhibitor-bound structure, suggesting that binding of the phosphate moiety of the substrate may trigger this conformational change. We suggest a new mechanism for catalysis that uses Glu357 as the base catalyst for the isomerase reaction rather than His388 as proposed previously. The human PGI structure has also provided a detailed framework with which to map mutations associated with non-spherocytic haemolytic anaemia.

What prevents GPs from using outside resources for women experiencing depression? A New Zealand study

BACKGROUND

GPs, often the 'gatekeepers' to mental health and related support services, have been found to refer on less often than seems desirable.

OBJECTIVES

The aim of this study was to explore what issues GPs would discuss with, and which treatments and support services they would consider for, depressed women; and to investigate barriers to referrals to other resources.

METHODS

All (217) GPs in one region of Auckland received questionnaires with a vignette and quantitative and qualitative questions concerning their responses to women experiencing depression. Twelve of the 86 respondents were interviewed.

RESULTS

GPs wanted to know about a range of medical, psychological and social issues. The solutions valued were biological and psychological, with some also favouring social interventions, such as assistance with childcare. However, the GPs reported limited referrals to outside resources, and frequent use of medication, because of the high cost and limited availability of psychological treatment, and difficulties accessing practical help.

CONCLUSIONS

This sample of GPs support improved accessibility, availability and affordability of psychological treatments and support services.

The contribution of early traumatic events to schizophrenia in some patients: a traumagenic neurodevelopmental model

The current diathesis-stress model of schizophrenia proposes that a genetic deficit creates a predisposing vulnerability in the form of oversenstivity to stress. This model positions all psychosocial events on the stress side of the diathesis-stress equation. As an example of hypotheses that emerge when consideration is given to repositioning adverse life events as potential contributors to the diathesis, this article examines one possible explanation for the high prevalence of child abuse found in adults diagnosed schizophrenic. A traumagenic neurodevelopmental (TN) model of schizophrenia is presented, documenting the similarities between the effects of traumatic events on the developing brain and the biological abnormalities found in persons diagnosed with schizophrenia, including overreactivity of the hypothalamic-pituitary-adrenal (HPA) axis; dopamine, norepinephrine, and serotonin abnormalities; and structural changes to the brain such as hippocampal damage, cerebral atrophy, ventricular enlargement, and reversed cerebral asymmetry. The TN model offers potential explanations for other findings in schizophrenia research beyond oversensitivity to stress, including cognitive impairment, pathways to positive and negative symptoms, and the relationship between psychotic and dissociative symptomatology. It is recommended that clinicians and researchers explore the presence of early adverse life events in adults with psychotic symptoms in order to ensure comprehensive formulations and appropriate treatment plans, and to further investigate the hypotheses generated by the TN model.

A mechanism of membrane neutral lipid acquisition by the microsomal triglyceride transfer protein

The microsomal triglyceride transfer protein (MTP) and apolipoprotein B (apoB) belong to the vitellogenin (VTG) family of lipid transfer proteins. MTP is essential for the intracellular assembly and secretion of apoB-containing lipoproteins, the key intravascular lipid transport proteins in vertebrates. We report the predicted three-dimensional structure of the C-terminal lipid binding cavity of MTP, modeled on the crystal structure of the lamprey VTG gene product, lipovitellin. The cavity in MTP resembles those found in the intracellular lipid-binding proteins and bactericidal/permeability-increasing protein. Two conserved helices, designated A and B, at the entrance to the MTP cavity mediate lipid acquisition and binding. Helix A (amino acids 725-736) interacts with membranes in a manner similar to viral fusion peptides. Mutation of helix A blocks the interaction of MTP with phospholipid vesicles containing triglyceride and impairs triglyceride binding. Mutations of helix B (amino acids 781-786) and of N780Y, which causes abetalipoproteinemia, have no impact on the interaction of MTP with phospholipid vesicles but impair triglyceride binding. We propose that insertion of helix A into lipid membranes is necessary for the acquisition of neutral lipids and that helix B is required for their transfer to the lipid binding cavity of MTP.

Complications according to mode of delivery among human immunodeficiency virus-infected women with CD4 lymphocyte counts of < or = 500/microL

OBJECTIVE

We sought to describe rates of and risk factors for complications by delivery mode among human immunodeficiency virus-infected women with CD4 counts of < or = 500/microL.

STUDY DESIGN

Complication rates were calculated by delivery mode, as follows: planned cesarean delivery performed without labor or rupture of membranes, other cesarean delivery performed after labor or rupture of membranes, or vaginal delivery. Risk factors were evaluated.

RESULTS

Major complications in the planned cesarean delivery (n = 37), other cesarean delivery (n = 95), and vaginal delivery (n = 365) groups were amnionitis or endometritis (16%, 27%, and 7%, respectively), wound infection (5%, 8%, and <1%, respectively), and transfusion (8%, 6%, and 3%, respectively). Any peripartum infection occurred among 16 (18%) of those with a CD4 count of <200/microL and 43 (13%) with a CD4 count of > or =200/microL (P =.17). On multivariate analyses, factors associated with amnionitis-endometritis were cesarean delivery and African American race, and a factor associated with transfusion was third-trimester anemia.

CONCLUSION

Endometritis and wound infection occurred more frequently among human immunodeficiency virus-infected women after cesarean than among women undergoing vaginal delivery; however, complication rates overall were within the range reported in human immunodeficiency virus-negative women. Measures to decrease complications in human immunodeficiency virus-infected women, such as greater use of prophylactic antibiotics, should be assessed.