Diversity of locally useful tropical forest wild-plants as a function of species richness and informant culture

Different conservation values and perspectives can lead to divergent conservation objectives. Understanding such differences is crucial to developing more comprehensive and inclusive conservation approaches. Using plots, we assessed how numbers of useful species as reported by indigenous forest-dwelling people relate to plant species richness. We used 173 plots recording both trees and herbaceous vegetation and the knowledge of both Merap- and Punan-dominated communities in Malinau, Kalimantan (Indonesian Borneo). We used general linear models (GLMs) to characterise the relationships. Useful species increase with species richness in all cases. The relationship varied across culture and community and was not always linear. The proportion of tree species reported as useful by Merap (primarily agriculturalist) informants was not constant but declined significantly as plot diversity increased; this was not the case for Punan (primarily hunter-gatherer) informants. There was no decline for the reported proportion of useful herbs as richness increases, as assessed by either ethnic group. Communities with less wealth and less schooling generally reported a higher proportion of the useful species. We interpret these results in terms of how landscape patterns of plant diversity are experienced. Understanding of these relationships can help us develop a more explicit approach to weighing and reconciling different conservation values and management objectives in changing forest landscapes.     

Chemical inhibition of bacterial protein tyrosine phosphatase suppresses capsule production

Capsule polysaccharide is a major virulence factor for a wide range of bacterial pathogens, including Streptococcus pneumoniae. The biosynthesis of Wzy-dependent capsules in both gram-negative and -positive bacteria is regulated by a system involving a protein tyrosine phosphatase (PTP) and a protein tyrosine kinase. However, how the system functions is still controversial. In Streptococcus pneumoniae, a major human pathogen, the system is present in all but 2 of the 93 serotypes found to date. In order to study this regulation further, we performed a screen to find inhibitors of the phosphatase, CpsB. This led to the observation that a recently discovered marine sponge metabolite, fascioquinol E, inhibited CpsB phosphatase activity both in vitro and in vivo at concentrations that did not affect the growth of the bacteria. This inhibition resulted in decreased capsule synthesis in D39 and Type 1 S. pneumoniae. Furthermore, concentrations of Fascioquinol E that inhibited capsule also lead to increased attachment of pneumococci to a macrophage cell line, suggesting that this compound would inhibit the virulence of the pathogen. Interestingly, this compound also inhibited the phosphatase activity of the structurally unrelated gram-negative PTP, Wzb, which belongs to separate family of protein tyrosine phosphatases. Furthermore, incubation with Klebsiella pneumoniae, which contains a homologous phosphatase, resulted in decreased capsule synthesis. Taken together, these data provide evidence that PTPs are critical for Wzy-dependent capsule production across a spectrum of bacteria, and as such represents a valuable new molecular target for the development of anti-virulence antibacterials.     

Smart Markers for Watershed-Based Cell Segmentation

Automated cell imaging systems facilitate fast and reliable analysis of biological events at the cellular level. In these systems, the first step is usually cell segmentation that greatly affects the success of the subsequent system steps. On the other hand, similar to other image segmentation problems, cell segmentation is an ill-posed problem that typically necessitates the use of domain-specific knowledge to obtain successful segmentations even by human subjects. The approaches that can incorporate this knowledge into their segmentation algorithms have potential to greatly improve segmentation results. In this work, we propose a new approach for the effective segmentation of live cells from phase contrast microscopy. This approach introduces a new set of “smart markers” for a marker-controlled watershed algorithm, for which the identification of its markers is critical. The proposed approach relies on using domain-specific knowledge, in the form of visual characteristics of the cells, to define the markers. We evaluate our approach on a total of 1,954 cells. The experimental results demonstrate that this approach, which uses the proposed definition of smart markers, is quite effective in identifying better markers compared to its counterparts. This will, in turn, be effective in improving the segmentation performance of a marker-controlled watershed algorithm.     

Regulation of neurocoel morphogenesis by Pard6 gamma b

The Par3/Par6/aPKC protein complex plays a key role in the establishment and maintenance of apicobasal polarity, a cellular characteristic essential for tissue and organ morphogenesis, differentiation and homeostasis. During a forward genetic screen for liver and pancreas mutants, we identified a pard6γb mutant, representing the first known pard6 mutant in a vertebrate organism. pard6γb mutants exhibit defects in epithelial tissue development as well as multiple lumens in the neural tube. Analyses of the cells lining the neural tube cavity, or neurocoel, in wildtype and pard6γb mutant embryos show that lack of Pard6γb function leads to defects in mitotic spindle orientation during neurulation. We also found that the PB1 (aPKC-binding) and CRIB (Cdc-42-binding) domains and the KPLG amino acid sequence within the PDZ domain (Pals1-and Crumbs binding) are not required for Pard6γb localization but are essential for its function in neurocoel morphogenesis. Apical membranes are reduced, but not completely absent, in mutants lacking the zygotic, or both the maternal and zygotic, function of pard6γb, leading us to examine the localization and function of the three additional zebrafish Pard6 proteins. We found that Pard6α, but not Pard6β or Pard6γa, could partially rescue the pard6γb^s441 mutant phenotypes. Altogether, these data indicate a previously unappreciated functional diversity and complexity within the vertebrate pard6 gene family.     

The ylo-1 gene encodes an aldehyde dehydrogenase responsible for the last reaction in the Neurospora carotenoid pathway

The accumulation of the apocarotenoid neurosporaxanthin and its carotene precursors explains the orange pigmentation of the Neurospora surface cultures. Neurosporaxanthin biosynthesis requires the activity of the albino gene products (AL-1, AL-2 and AL-3), which yield the precursor torulene. Recently, we identified the carotenoid oxygenase CAO-2, which cleaves torulene to produce the aldehyde β-apo-4'-carotenal. This revealed a last missing step in Neurospora carotenogenesis, namely the oxidation of the CAO-2 product to the corresponding acid neurosporaxanthin. The mutant ylo-1 , which exhibits a yellow colour, lacks neurosporaxanthin and accumulates several carotenes, but its biochemical basis is unknown. Based on available genetic data, we identified ylo-1 in the Neurospora genome, which encodes an enzyme representing a novel subfamily of aldehyde dehydrogenases, and demonstrated that it is responsible for the yellow phenotype, by sequencing and complementation of mutant alleles. In contrast to the precedent structural genes in the carotenoid pathway, light does not induce the synthesis of ylo-1 mRNA. In vitro incubation of purified YLO-1 protein with β-apo-4'-carotenal produced neurosporaxanthin through the oxidation of the terminal aldehyde into a carboxyl group. We conclude that YLO-1 completes the set of enzymes needed for the synthesis of this major Neurospora pigment.     

Treatment of tetanus: an open study to compare the efficacy of procaine penicillin and metronidazole.

A prospective, open, non-randomised clinical trial was carried out to compare the efficacy of procaine penicillin with metronidazole in the treatment of moderate tetanus among 173 patients. Patients in the metronidazole group had a significantly lower mortality rate, a shorter stay in hospital, and an improved response to treatment. These results establish the value of antimicrobial treatment in the management of tetanus and show that metronidazole is more efficacious than penicillin in this respect.     

Rapid plant regeneration,validation of genetic integrity by ISSR markers and conservation of Reseda pentagyna an endemic plant growing in Saudi Arabia

Reseda pentagyna is the only endemic species among the seven species of the genera Reseda found in Saudi Arabia. Probably no information is available on regeneration by conventional method of regeneration through seeds or cuttings. Therefore, alternative method of tissue culture was attempted to regenerate and multiply the plant. High shoot regeneration (14.44 shoots/explant) was obtained after four weeks, when shoot cuttings cultured on MS containing BA at 1.0 µM. Other cytokinins e.g., Kn, 2iP and TDZ found to be less effective in bud induction and shoot multiplication. Individual shoots were rooted on MS medium supplemented with various auxins at 0.5–5.0 µM concentrations. The IBA (1.5 µM) supplemented MS media induced maximum (83.3%) rooting. The plantlets were acclimatized and hardened under greenhouse conditions in plastic pots containing soil and farm yard manure with 95.0% success. The protocol developed would help to multiply the plant as well as conserve them in natural habitat. This can also be utilized to obtain active constituents for pharmaceutics and genetic manipulations.     

Porewater nutrient profiles and nutrient sediment–water exchange in a tropical mangrove waterway, Mapopwe Creek, Chwaka Bay, Zanzibar

Sediments were examined in the Mapopwe Creek, a tidally dominated mangrove waterway in the Chwaka Bay mangrove forest, Zanzibar, to assess their significance in the nutrient dynamics of the mangrove forest and the adjacent bay. Porewater concentrations of dissolved ammonium and that of soluble reactive phosphorus (SRP) were generally higher during the dry season than during the wet season. NO₃^? plus NO₂^? concentration averaged 1 µm and did not vary much between the two periods. Fluxes of ammonium ranged from ?575 to 523 µm m^?2 h^?1 and those of SRP from ?55.7 to 69.5 µm m^?2 h^?1. Measurements of NO_x did not show any consistent fluxes of this dissolved nitrogen species. Variations of flux rates between the two seasons were not significant even though there were small variations in the flux direction in both nutrients. Results imply that Mapopwe sediments are a source of NH₄⁺ but act as a sink for SRP.