Precipitation-dependent flowering of Globularia alypum and Erica multiflora in Mediterranean shrubland under experimental drought and warming, and its inter-annual variability

Background and Aims

Relationships between autumn flowering, precipitation and temperature of plant species of Mediterranean coastal shrublands have been described, but not analysed experimentally. These relationships were analysed for two species of co-occurring, dominant, autumn-flowering shrubs, Globularia alypum and Erica multiflora, over 4 years and in experimentally generated drought and warming conditions. The aim was to improve predictions about the responses and adaptations of flowering of Mediterranean vegetation to climate change.

Methods

Beginning of anthesis and date of maximum flowering intensity (‘peak date’) were monitored over 4 years (2001–2004) on a garrigue land type in the noth-east of the Iberian Peninsula. Two experimental treatments were applied, increased temperature (+0·73°C) and reduced soil moisture (–17%) relative to untreated plots.

Key Results

Flowering of Globularia alypum and Erica multiflora differed greatly between years depending on the precipitation of the previous months and the date of the last substantial rainfall (>10 mm). Globularia alypum flowered once or twice (unimodal or bimodal) as the result of differences in the distribution and magnitude of precipitation in late-spring and summer (when floral buds develop). The drought treatment delayed and decreased flowering of Globularia alypum in 2001 and delayed flowering in 2002. Warming extended the period between the beginning of flowering and the end of the second peak for autumn flowering in 2001 and also increased peak intensity in 2002. Flowering of Erica multiflora was unaffected by either treatment.

Conclusions

Autumn flowering of Globularia alypum and Erica multiflora is more dependent on water availability than on temperature. Considerable inter-annual plasticity in the beginning of anthesis and peak date and on unimodal or bimodal flowering constitutes a ‘safe strategy’ for both species in relation to varying precipitation and temperature. However, severe changes in precipitation in spring and summer may severely affect flowering of Globularia alypum but not Erica multiflora, thus affecting development/structure of the ecosystem if such conditions persist.Key words: Globularia alypum, Erica multiflora, autumn flowering, drought, global warming, Mediterranean     

<Emphasis Type="Italic">Anacamptis</Emphasis> versus <Emphasis Type="Italic">Orchis</Emphasis> (Orchidaceae): seed micromorphology and its taxonomic significance

Seed micromorphology of 24 taxa of the genera Anacamptis and Orchis was examined under light and scanning electron microscopy. Seed qualitative characters appear very useful at the supraspecific level in the subtribe Orchidinae. Based on our observations, the sculpturing of the periclinal walls of the medial testa cells, the seed shape and several features of the anticlinal walls of the apical cells showed variability between the studied taxa, with special relevance of the first character. According to this factor, we found one type of seed for Anacamptis and two for Orchis. The taxonomic value of seed coat characters is compared with the last taxonomic proposals for the genera Anacamptis and Orchis.     

TIE-2/VEGF-R2 SAR and in vitro activity of C3-acyl dihydroindazolo[5,4-a]pyrrolo[3,4-c]carbazole analogs

Orally bioavailable, dual inhibitors of TIE-2/VEGF-R2 were identified by elaborating the C3/N13 SAR around a fused pyrrolodihydroindazolocarbazole scaffold. Analogs bearing a C3-thiophencarbonyl group were evaluated in enzymatic and cellular biochemical assays; two orally bioavailable analogs were further profiled in functional assays and found to inhibit microvessel growth in rat aortic explant cultures and inhibit Ang-1-stimulated chemotaxis of HUVECs.     

Individual predisposition, household clustering and risk factors for human infection with Ascaris lumbricoides: new epidemiological insights

Background

Much of our current understanding of the epidemiology of Ascaris lumbricoides infections in humans has been acquired by analyzing worm count data. These data are collected by treating infected individuals with anthelmintics so that worms are expelled intact from the gastrointestinal tract. Analysis of such data established that individuals are predisposed to infection with few or many worms and members of the same household tend to harbor similar numbers of worms. These effects, known respectively as individual predisposition and household clustering, are considered characteristic of the epidemiology of ascariasis. The mechanisms behind these phenomena, however, remain unclear. In particular, the impact of heterogeneous individual exposures to infectious stages has not been thoroughly explored.

Methodology/Principal Findings

Bayesian methods were used to fit a three-level hierarchical statistical model to A. lumbricoides worm counts derived from a three-round chemo-expulsion study carried out in Dhaka, Bangladesh. The effects of individual predisposition, household clustering and household covariates of the numbers of worms per host (worm burden) were considered simultaneously. Individual predisposition was found to be of limited epidemiological significance once household clustering had been accounted for. The degree of intra-household variability among worm burdens was found to be reduced by approximately 58% when household covariates were included in the model. Covariates relating to decreased affluence and quality of housing construction were associated with a statistically significant increase in worm burden.

Conclusions/Significance

Heterogeneities in the exposure of individuals to infectious eggs have an important role in the epidemiology of A. lumbricoides infection. The household covariates identified as being associated with worm burden provide valuable insights into the source of these heterogeneities although above all emphasize and reiterate that infection with A. lumbricoides is inextricably associated with acute poverty.     

Excision of a selectable marker gene in transgenic banana using a Cre/lox system controlled by an embryo specific promoter

Antibiotic and herbicide resistance genes have been used in transgene technology as powerful selection tools. Nonetheless, once transgenic events have been obtained their presence is no longer needed and can even be undesirable. In this work, we have developed a system to excise the selectable marker and the cre recombinase genes from transgenic banana cv. ‘Grande Naine’ (Musa AAA). To achieve this, the embryo specific REG-2 promoter was isolated from rice and its expression pattern in banana cell clumps, somatic embryos and regenerated plantlets was characterized by using a pREG2::uidA fusion construct. Subsequently, the REG-2 promoter was placed upstream of the cre gene, conferring Cre functionality in somatic embryos and recombination of lox sites resulting in excision of the selectable marker and cre genes. PCR analysis revealed that 41.7 % of the analysed transgenic plants were completely marker free, results that were thereafter confirmed by Southern blot hybridization. These results demonstrate the feasibility of using developmentally controlled promoters to mediate marker excision in banana. This system does not require any extra handling compared to the conventional transformation procedure and might be useful in other species regenerating through somatic embryogenesis.     

Nitrogen-fixing cyanobacteria as source of phycobiliprotein pigments. Composition and growth performance of ten filamentous heterocystous strains

Ten strains of filamentous, heterocystous nitrogen-fixing blue-green algae (cyanobacteria) were screened for growth performance and tolerance to temperature, pH, irradiance and salinity, together with their potential as producers of phycobiliprotein pigments. Phycobiliproteins typically accounted for about 50% total cell protein, the prevalent type being C-phycocyanin, followed by alloppycocyanin, with levels of 17 and 11% d.wt, respectively, in some strains of Anabaena and Nostoc. C-phycoerythrin was the major pigment in several Nostoc strains, reaching 10% d.wt. Some strains represent, therefore, excellent sources of one or more phycobiliproteins. All strains tolerated an irradiance of ca 2000 μmol photon m^-2 s^-1. Anabaena sp. ATCC 33047 and Nostoc sp. (Albufera) exhibited the widest optimum range of both temperature (30–45 and 25–40 °C) and pH (6.5–9.5 and 6.0–9.0) for growth, the former also showing significant salt tolerance. In an outdoor open system, productivity of cultures of two phycoerythrin-rich strains of Nostoc was over 20 g (d.wt) m^-2 d^-1 during summer. The growth performance of the allophycocyanin-rich Anabaena sp. ATCC 33047 in outdoor semi-continuous culture has been assessed throughout the year. Productivity values under optimized conditions ranged from 9 (winter) to 24 (summer) g (d.wt) m^-2 d^-1.