Discovery of a life history shift: precocious flowering in an introduced population of Prosopis

The genus Prosopis contains many valuable, long-lived, multi-purpose legume trees, some of which are also invasive species. The time of first flowering is important for increasing production of sweet, protein-rich pods in plantations, especially under short rotations, and affects the rate of spread as a weed. Trees generally begin flowering at 3–5 years of age. However, seedlings from a small seedlot collected from an introduced population in southern Mauritania were observed to begin flowering at 3–4 months after germination. This is unknown in the native range of any Prosopis species, and appears to represent a major evolutionary event triggered after naturalization. This paper reports a detailed investigation with seed collected from Aleg, Brakna region, Mauritania, in 1998 (Prosopis sp. ‘Aleg’). Two experiments were established, in glasshouses at Cirad, Montpellier, France, and Coventry University, UK. Flowering began at the two sites 104 and 169 days after sowing, respectively, and 97.5% of plants had flowered at Coventry after 306 days. Flowers produced abundant pollen with 50–60% viability indicated by FDA staining and 40–50% germination on an artificial medium. No pods were formed. All plants analysed were diploid. Morphologically, these juvenile plants were similar to American species of section Algarobia, and exhibited leaf characters typical of P. pallida. However, due to the large variation in morphology within this section of the genus, further studies are required to confirm the actual species. This is the first record of precocious flowering in Prosopis, and has been found only in a single, introduced population. Implications for genetic improvement of tropical Prosopis, and particularly the spread of these species as invasive weeds, are discussed. Such a life history shift in the increased reproductive ability of a species following introduction, with potentially significant environmental effects, may not be restricted to Prosopis and merits further detailed investigation.     

Long polar fimbriae and tissue tropism in Escherichia coli O157:H7

In vitro organ culture has demonstrated the human intestinal tropism of enterohaemorrhagic Escherichia coli O157:H7 for follicle associated epithelium overlying Peyer's patches of the terminal ileum. Long polar (LP) fimbriae are considered to mediate the attachment of Salmonella enterica serovar Typhimurium to Peyer's patch epithelium and, as homologous genes have been identified in O157:H7, we hypothesised that LP fimbriae in O157:H7 may perform the same function. However, mutation of LP fimbriae in O157:H7 strain 85/170 resulted in the novel phenotype of proximal and distal small intestinal colonisation with attaching/effacing lesion formation, while retaining adhesion to follicle associated epithelium. Application of whole genome DNA array technology did not identify changes in known fimbrial genes that could explain the change in tropism, but highlighted several genes that require further investigation. LP fimbrial genes are the first genes to be identified outside the locus of enterocyte effacement pathogenicity island that influence O157:H7 human intestinal tissue tropism.     

NaCl enhances growth and morphogenesis potential of Alhagi graecorum

Summary The contamination of soils with excess salts is one of the greatest challenges to plant survival, but some unique species have evolved to thrive in highly saline environments. One such species, Alhagi graecorum Boiss., has been previously shown to accumulate high levels of sodium while growing in salt marshes. The aim of this research was to investigate the effects of saline conditions on the growth and the regeneration capacity of this species. Plantlets and explants of A. graecorum were cultured on a medium supplemented with various concentrations of NaCl, where A. graecorum tissues accumulated up to 8% Na⁺. The capacity for regeneration was enhanced by the excess sodium, indicating a requirement of salt for optimal growth and development in this species. Further study of this species may provide new concepts and understanding of the metabolism of sodium in higher plants.     

INCITE: A randomised trial comparing constraint induced movement therapy and bimanual training in children with congenital hemiplegia

Background  

Congenital hemiplegia is the most common form of cerebral palsy (CP) accounting for 1 in 1300 live births. These children have limitations in capacity to use the impaired upper limb and bimanual coordination deficits which impact on daily activities and participation in home, school and community life. There are currently two diverse intensive therapy approaches. Traditional therapy has adopted a bimanual approach (BIM training) and recently, constraint induced movement therapy (CIMT) has emerged as a promising unimanual approach. Uncertainty remains about the efficacy of these interventions and characteristics of best responders. This study aims to compare the efficacy of CIMT to BIM training to improve outcomes across the ICF for school children with congenital hemiplegia.     

Characterization of phosphorus fractions in the sediments of a tropical intertidal mangrove ecosystem

Solid phases of phosphorus fractions in the surface and core sediments were studied to understand the biogeochemical cycling and bioavailability of phosphorus in the Pichavaram intertidal mangrove sediments of India. Total P in surface and core sediments ranged between 451–552 and 459–736 μg g⁻¹ respectively and Fe bound P was the dominant fraction. Low levels of Fe bound P in the mangrove zone than the two estuarine zones may be because of high salinity inhibition of phosphate adsorption onto the Fe-oxides/hydroxides. Post-depositional reorganization of P was observed in surface sediments, converting organic P and Fe bound P into the authigenic P. High levels of organic P in the mangrove zone is primarily due to intensive cycling and degradation of organic matter and adsorption of phosphate on the organic molecules. The burial rates and regeneration efficiency of P in the intertidal mangrove ecosystem ranged from 5.41 to 7.27 μmol P cm⁻² year⁻¹ and 0.122 to 0.233 μmol P cm⁻² year⁻¹, respectively. High burial efficiency (≈99%) of P proves the earlier observation of limiting nature of P for the biological productivity. Further, bioavailable P (exchangeable P + Fe bound P + organic P) constituted a considerable proportion of sedimentary P pool of which an average accounted for 55 and 50% in surface and core sediments respectively. The results indicate that significant amount of P is locked in sediments in the form of authigenic P and detrital P which makes P as a limiting nutrient for the biological productivity.     

Regeneration of the Egyptian medicinal plant <Emphasis Type="Italic">Artemisia judaica</Emphasis> L.

An in vitro propagation system for Artemisia judaica L., a traditional Egyptian medicinal plant, has been developed. De novo shoot organogenesis was induced by culturing etiolated hypocotyls and intact seedlings on medium supplemented with thidiazuron [N-phenyl-N'-(1,2,3-thidiazol-yl) urea] via callusing at the cotyledonary notch region. Up to 16 shoots formed per seedling cultured on a medium containing 1 micro mol l(-1) thidiazuron for an optimal duration of exposure of 20 days. Regenerated shoots formed roots when subcultured onto a medium containing 1 micromol l(-1) indole-3-butyric acid. The regeneration protocol developed in this study provides a basis for germplasm conservation and for further investigation of medicinally active constituents of A. judaica.     

Development and prospective validation of a model for predicting weaning in chronic ventilator dependent patients

Background

HTLV-I infection has been linked to lung pathology and HTLV-II has been associated with an increased incidence of pneumonia and acute bronchitis. However it is unknown whether HTLV-I or -II infection alters pulmonary function.

Methods

We performed pulmonary function testing on HTLV-I, HTLV-II and HTLV seronegative subjects from the HTLV outcomes study (HOST), including vital capacity (VC), forced expiratory volume in one second (FEV₁), and diffusing lung capacity for carbon monoxide (DLCO) corrected for hemoglobin and lung volume. Multivariable analysis adjusted for differences in age, gender, race/ethnicity, height and smoking history.

Results

Mean (standard deviation) pulmonary function values among the 257 subjects were as follows: FVC = 3.74 (0.89) L, FEV₁ = 2.93 (0.67) L, DLCO_corr = 23.82 (5.89) ml/min/mmHg, alveolar ventilation (VA) = 5.25 (1.20) L and DLCO_corr/VA = 4.54 (0.87) ml/min/mmHg/L. There were no differences in FVC, FEV1 and DLCO_corr/VA by HTLV status. For DLCO_corr, HTLV-I and HTLV-II subjects had slightly lower values than seronegatives, but neither difference was statistically significant after adjustment for confounding.

Conclusions

There was no difference in measured pulmonary function and diffusing capacity in generally healthy HTLV-I and HTLV-II subjects compared to seronegatives. These results suggest that previously described HTLV-associated abnormalities in bronchoalveolar cells and fluid may not affect pulmonary function.     

Spatial distribution of vectors of Ross River virus and Barmah Forest virus on Russell Island, Moreton Bay, Queensland

Abstract We used a network of 20 carbon dioxide- and octenol-supplemented light traps to sample adult mosquitoes throughout Russell Island in southern Moreton Bay, south-east Queensland. Between February and April 2001, an estimated 1365 564 adult female mosquitoes were collected. In contrast to an average catch of 9754 female mosquitoes per trap night on Russell Island, reference traps set on Macleay Island and on the mainland returned average catches of 3172 and 222, respectively. On Russell Island, Ochlerotatus vigilax (Skuse), Coquillettidia linealis (Skuse), Culex annulirostris Skuse and Verrallina funerea (Theobald), known or suspected vectors of Ross River (RR) and/or Barmah Forest (BF) viruses, comprised 89.6% of the 25 taxa collected. When the spatial distributions of the above species were mapped and analysed using local spatial statistics, all were found to be present in highest numbers towards the southern end of the island during most of the 7 weeks. This indicated the presence of more suitable adult harbourage sites and/or suboptimal larval control efficacy. As immature stages and the breeding habitat of Cq. linealis are as yet undescribed, this species in particular presents a considerable impediment to proposed development scenarios. The method presented here of mapping the numbers of mosquitoes throughout a local government area allows specific areas that have high vector numbers to be defined.     

Isospora dawadimiensis n. sp. (Protozoa: Eimeriidae) from the Jerboa (Jaculus jaculus) in Saudi Arabia

Isospora dawadimiensis n. sp. is described from the jerboa, Jaculus jaculus, from Dawadimi, Saudi Arabia. Sporulated oocysts of I. dawadimiensis n. sp. were ovoidal or nearly subspherical 22–26.5 times 20.5–22 μm (24.4 times 21.4 μm). Oocyst wall had one layer. Micropyle, oocyst residuum, and polar granule were absent. Sporocysts were ellipsoid 12–16.5 times 9–10.5 μm (14.6 times 9.9 μm). Sporocyst residuum was present. The sporocysts lack a Stieda body. Sporozoites 8–11 times 2–3 μm (10 times 2.6 μm) were sausage-shaped, slightly curved, and tapered at one end.     

Continuous ethanol production byZymomonas mobilis andSaccharomyces cerevisiae in biofilm reactors

Continuous ethanol fermentations were performed in duplicate for 60 days withZymomonas mobilis ATCC 331821 orSaccharomyces cerevisiae ATCC 24859 in packed-bed reactors with polypropylene or plastic composite-supports. The plastic composite-supports used contained polypropylene (75%) with ground soybean-hulls (20%) and zein (5%) forZ. mobilis, or with ground soybean-hulls (20%) and soybean flour (5%) forS. cerevisiae. Maximum ethanol productivities of 536 gL^–1 h^–1 (39% yield) and 499 gL^–1 h^–1 (37% yield) were obtained withZ. mobilis on polypropylene and plastic composite-supports of soybean hull-zein, respectively. ForZ. mobilis, and optimal yield of 50% was observed at a 1.92h^–1 dilution rate for soybean hull-zein plastic composite-supports with a productivity of 96gL^–1h^–1, whereas with polypropylene-supports the yield was 32% and the productivity was 60gL^–1h^–1. With aS. cerevisiae fermentation, the ethanol production was less, with a maximum productivity of 76gL^–1h^–1 on the plastic composite-support at a 2.88h^–1 dilution rate with a 45% yield. Polypropylene-support bioreactors were discontinued due to reactor plugging by the cell mass accumulation. Support shape (3-mm chips) was responsible for bioreactor plugging due to extensive biofilm development on the plastic composite-supports. With suspensionculture continuous fermentations in continuously-stirred benchtop fermentors, maximum productivities of 5gL^–1h^–1 were obtained with a yield of 24 and 26% withS. cerevisiae andZ. mobilis, respectively. Cell washout in suspensionculture continuous fermentations was observed at a 1.0h^–1 dilution rate. Therefore, for continuous ethanol fermentations, biofilm reactors out-performed suspension-culture reactors, with 15 to 100-fold higher productivities (gL^–1h^–1) and with higher percentage yields forS. cerevisiae andZ. mobilis, respectively. Further research is needed with these novel supports to evaluate different support shapes and medium compositions that will permit medium flow, stimulate biofilm formation, reduce fermentation costs, and produce maximum yields and productivities.This is Journal Paper No. J-16357 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa. Project No. 3253