Cavity-nesting birds are limited by nesting habitat in Neotropical agricultural landscapes

Most studies comparing biodiversity between natural and human-modified landscapes focus on patterns in species occurrence or abundance, but do not consider how different habitat types meet species' breeding requirements. Organisms that use or nest in tree cavities may be especially threatened by habitat conversion due to the loss of their nesting sites. Although cavity-nesting bird diversity is highest in the tropics, little is known about how tropical birds use cavities, how agriculture affects their reproductive biology, and how effective nest boxes could be as a conservation strategy in tropical agriculture. Here, we explored how habitat conversion from tropical forests to pasture affects the abundance, nesting habitat availability, and nest success of cavity-nesting birds in Northwest Ecuador. We conducted bird surveys and measured natural cavity availability and use in forest and agriculture. We also added artificial nest boxes to forest and agriculture to see whether cavity limitation in agriculture would elicit higher use of artificial nest boxes. We found evidence of cavity limitation in agriculture—there were many more natural cavities in forest than in agriculture, as well as more avian use of nest boxes placed in agriculture as compared to forest. Our results suggest that it is important to retain remnant trees in tropical agriculture to provide critical nesting habitat for birds. In addition, adding nest boxes to tropical agricultural systems could be a good conservation strategy for certain species, including insectivores that could provide pest-control services to farmers. Abstract in Spanish is available with online material.     

Mapping of the human homologs of the murine paired-box-containing genes

Mutations in paired-box-containing (Pax) genes have recently been found to be the primary lesions underlying human genetic disorders such as Waardenburg's Syndrome type 1 and mouse developmental mutants such as undulated (un), splotch (Sp), and small eye (Sey). In addition, PAX-6 is a strong candidate gene for aniridia in man. Eight independent Pax genes have been isolated in the mouse. All eight map to distinct regions of the mouse genome; they do not appear to be clustered in the same way as some groups of homeobox-containing genes. We have now mapped the human homologs of all eight of these genes; PAX genes are found on human Chromosomes (Chr) 1, 2, 7, 9, 10, 11, and 20.     

THE ECOLOGICAL IMPACT OF ALLELOPATHY IN AILANTHUS ALTISSIMA (SIMAROUBACEAE)

Compounds inhibitory to the growth of neighboring plant species were found in significant concentrations in the leaves and stems of young Ailanthus altissima ramets. The surrounding soil also contained appreciable concentrations of similarly acting toxins. Individuals of neighboring plant species have either incorporated active portions of inhibitory compounds or responded to Ailanthus by producing growth-inhibiting substances. Under greenhouse conditions, individuals of neighboring plant species previously unexposed to Ailanthus in the field were found to be more susceptible to the Ailanthus toxins than individuals previously exposed. Moreover, seeds produced by unexposed populations were also more susceptible to Ailanthus toxins than seeds produced by previously exposed populations. These differences demonstrated that the allelochemicals of Ailanthus altissima exhibited a measurable impact upon neighboring plant species. Since the progeny of these populations displayed a differential response to Ailanthus toxin, this phenotypic difference between the two populations may have a heritable basis.     

Compliance therapy in psychotic patients: randomised controlled trial.

OBJECTIVE--To determine whether compliance therapy, a cognitive-behavioural intervention, could improve compliance with treatment and hence social adjustment in acutely psychotic inpatients, and if so, whether the effect persisted six months later. DESIGN--Randomised controlled trial of compliance therapy and non-specific counselling, each comprising 4-6 sessions lasting 10-60 minutes. SETTING--Acute psychiatric admissions ward serving an inner London catchment area. SUBJECTS--47 patients with psychosis. MAIN OUTCOME MEASURES--Informant and observer reported measure of compliance; observer assessed global functioning after intervention and three and six months later; self-rated attitudes to drug treatment after the intervention and one month later; symptom scores after intervention and six months later. RESULTS--25 patients received compliance therapy and showed significantly greater improvements in their attitudes to drug treatment and in their insight into illness and compliance with treatment compared with the control group. These gains persisted for six months. The intervention group was 5.2 times more likely than the control group to reach a criterion level of compliance (95% confidence interval 1.5 to 18.3). Global functioning showed a tendency to improve more in the intervention group after a delay (odds ratio 3.0 (0.8 to 11.5) to reach the criterion level at six months). Four subjects given compliance therapy and six in the control group were readmitted during follow up (odds ratio 2.0 (0.48 to 8.2)). CONCLUSIONS--Compliance therapy is a pragmatic method for improving compliance with drug treatment in psychotic inpatients and its gains persist for at least six months. Overall functioning may also be enhanced.     

The elongation of amylose and amylopectin chains in isolated starch granules

The aim of this work was to investigate the conditions required for amylose synthesis in starch granules. Although the major granule-bound isoform of starch synthase - GBSSI - catalyses the synthesis of amylose in vivo, ¹⁴C from ADP[¹⁴C]glucose was incorporated primarily into a specific subset of amylopectin chains when supplied to starch granules isolated from pea (Pisum sativum L.) embryos and potato (Solanum tuberosum L.) tubers. Incubation of granules with soluble extracts of these organs revealed that the extracts contained compounds that increased the incorporation of ¹⁴C into amylose. These compounds were rendered inactive by treatment of the extracts with α-glucosidase, suggesting that they were malto-oligosaccharides. Consistent with this idea, provision of pure malto-oligosaccharides to isolated granules resulted in a dramatic shift in the pattern of incorporation of ¹⁴C, from amylopectin chains to amylose molecules. Comparison of the pattern of incorporation in granules from wild-type peas and lam mutant peas which lack GBSSI showed that this effect of malto-oligosaccharides was specifically on GBSSI. The significance of these results for understanding of the synthesis of amylose and amylopectin in storage organs is discussed.     

Characterization of tobacco plants expressing a bacterial salicylate hydroxylase gene

Transgenic tobacco plants that express the bacterial nahG gene encoding salicylate hydroxylase have been shown to accumulate very little salicylic acid and to be defective in their ability to induce systemic acquired resistance (SAR). In recent experiments using transgenic NahG tobacco and Arabidopsis plants, we have also demonstrated that salicylic acid plays a central role in both disease susceptibility and genetic resistance. In this paper, we further characterize tobacco plants that express the salicylate hydroxylase enzyme. We show that tobacco mosaic virus (TMV) inoculation of NahG tobacco leaves induces the accumulation of the nahG mRNA in the pathogen infected leaves, presumably due to enhanced stabilization of the bacterial mRNA. SAR-associated genes are expressed in the TMV-infected leaves, but this is localized to the area surrounding necrotic lesions. Localized acquired resistance (LAR) is not induced in the TMV-inoculated NahG plants suggesting that LAR, like SAR, is dependent on SA accumulation. When SA is applied to nahG-expressing leave's SAR gene expression does not result. We have confirmed earlier reports that the salicylate hydroxylase enzyme has a narrow substrate specificity and we find that catechol, the breakdown product of salicylic acid, neither induces acquired resistance nor prevents the SA-dependent induction of the SAR genes.     

The effects of calystegines isolated from edible fruits and vegetables on mammalian liver glycosidases

The polyhydroxylated nortropane alkaloids called calyste-ginesoccur in many plants of the Convolvulaceae, Solanaceae, andMoraceae families. Certain of these alkaloids exhibit potentinhibitory activities against glycosidases and the recentlydemonstrated occurrence of calystegines in the leaves, skins,and sprouts of potatoes (Solatium tuberosum), and in the leavesof the eggplant (S.melongena), has raised concerns regardingthe safety of these vegetables in the human diet. We have surveyedthe occurrence of calystegines in edible fruits and vegetablesof the families Convolvulaceae, Solanaceae, and Moraceae byGC-MS. Calystegines A3, B1, B2, and C1 were detected in allthe edible fruits and vegetables tested; sweet and chili peppers,potatoes, eggplants, tomatoes, Physalis fruits, sweet potatoes,and mulberries. Calystegines B1 and C1 were potent competitiveinhibitors of the bovine, human, and rat β-glucosidaseactivities, with K₁ values of 150, 10, and 1.9 µM, respectivelyfor B1 and 15,1.5, and 1 µM, respectively, for C1. CalystegineB2 was a strong competitive inhibitor of the -galactosidaseactivity in all the livers. Human β-xylosidase was inhibitedby all four nortropanes, with calystegine C1 having a K₁ of0.13 µM. Calystegines A3 and B2 selectively inhibitedthe rat liver β-glucosidase activity. The potent inhibitionof mammalian β-glucosidase and -galactosidase activitiesin vitro raises the possibility of toxicity in humans consuminglarge amounts of plants that contain these compounds. edible plants calystegines glycosidase inhibitors bovine, human, and rat liver