Assessment of ecological status in U.K. rivers using diatoms

1. The European Union's Water Framework Directive requires all water bodies to achieve ‘good ecological status’ by 2015 and this paper describes a rationale for defining ‘good ecological status’ based on diatoms, a significant component of the biological quality element ‘macrophyte and phytobenthos’. 2. A database of benthic diatom samples collected over the past 20 years was assembled. New sampling, specifically for this project, was undertaken during 2004 to supplement these data. In total 1051 samples were included in the database with matching environmental data. 3. ‘Reference sites’, relatively unimpacted by human activity, were selected from this database by a series of screening steps and these sites were used to develop a site‐specific reference typology. 4. Environmental variables not related to the pressure gradient were used to predict the ‘expected’ Trophic Diatom Index (TDI) values at each site. Site‐specific TDI predictions were used to generate ecological quality ratios (EQRs) ranging from ≥1, where the diatom assemblage showed no impact, to (theoretically) 0, when the diatom assemblage was indicative of major anthropogenic activities. 5. The boundary between ‘high’ and ‘good’ status was defined as the 25th percentile of EQRs of all reference sites. The boundary between ‘good’ and ‘moderate’ status was set at the point at which nutrient‐sensitive and nutrient‐tolerant taxa were present in equal relative abundance. An ecological rationale for this threshold is outlined in the paper.     

Sexual Reproduction and Early Plant Growth of the Wollemi Pine (Wollemia nobilis), a Rare and Threatened Australian Conifer

The two known populations of the recently discovered rare andthreatened Wollemi Pine (Wollemia nobilis Jones, Hill and Allen)consist of a small number of large multi-stemmed adult treesand small seedlings. Female and male cones are produced on adulttrees with pollen release occurring in spring (October–November).Seed cones mature 16–19 months later in late summer andautumn and appear to be produced annually. Approximately 10%of seed produced in two consecutive years was viable, 25% ofwhich was damaged by animals. Glasshouse studies showed thatseed germination at 25 °C (day)/16 °C (night) proceededslowly but steadily at approx. 4% per week until, after 6 months,88% of apparently viable seed had germinated with the remainderof the seed rotting. Growth of potted seedlings in this temperatureregime was continuous (after a lag period of 4–6 months)with the monopodial axis growing 0.05–0.25 m in the firstyear, 0.5–0.6 m in the second year and 0.25–0.35m in the third year, attaining a total height of 0.8–1.2m. Multiple orthotropic shoots developed on some plants at thisstage, some of which outgrew the primary shoot in height. Thediameter of the stem below the cotyledon (just above the soil)grew 3–7 mm in the first year, 10–14 mm in the secondand 15–20 mm in the third at which time it was 25–34mm. The average number of lateral branches produced was five–17in the first year, 25–36 in the second year and 24–30in the third year giving a total of 60–77. The establishmentof Wollemi Pine in the wild does not appear limited by the inherentviability of seed and potential for early growth of seedlings.Copyright 1999 Annals of Botany Company Wollemia nobilis, Wollemi Pine, Araucariaceae, conifer, rare and threatened plant, cone, seed, germination, seedling growth.     

Preparation of Radioactive Starch, Glucose and Fructose from C14O2

Radioactive starch, glucose and fructose have been preparedfrom tobacco leaves after assimilation of C¹⁴O₂. The apparatusused for photosynthesis consisted of a shallow Perspex leafchamber connected to a closed gas system, in which C¹⁴O₂ wasgenerated from BaC¹⁴O₂. Six leaves, area 14 to 18 sq. dm. whenexposed to bright sunlight with an initial CO₂ concentrationof 8 to 10 per cent., assimilated 3.35 g. of C¹⁴O₂ in 8 to 10hours. At least 80 per cent. of the C¹⁴O₂ supplied appearedin the leaves as starch and sugar and over 80 per cent. of theradioactivity was accounted for in these carbohydrates. Thespecific activity per m. atom of carbon of the isolated productswas 85 to 90 per cent. of that of the C¹⁴O₂. Small amounts ofradioactive carbon were also incorporated in the leaf proteinand in the celluose, hemicellulose and polyuronides.     

SEM study of surface structures of the spathe in Cryptocoryne and Lagenandra (Araceae: Aroideae: Cryptocoryneae)

SEM studies of the spathe structures in the two closely related genera Cryptocoryne and Lagenandra show differences between the inner and outer surfaces, as well as in cell structures in the various parts of the spathe. The cell structure reveals patterns mat makes it possible to depict homologous structures of the spathe, even though the spathes of the two genera look different. The basal part of the kettle has a mucilage covering of the cells, interpreted as a hitherto unnoticed food source. The cells of the inner surface of the kettle and tube have downward pointing trichomes. On the second day of flowering these collapse and sink into the cell lumen, which is suggested to create a unique lattice-like structure that enables the insects to climb out of the kettle and tube. The cell structure of the flap shows that it is a prolongation and continuation of the spathe tube margin.     

Can Lactobacillus spp. Be a Factor Reducing the Risk of Miscarriage?

Pregnancy loss is a common obstetric problem. Significant causes of miscarriage include genetic and epigenetic disorders of the embryo, immunological and endocrine factors, uterine malformations, improper embryo selection, and lifestyle. Perhaps a hitherto underappreciated cause of miscarriage may be an abnormal microbiota composition of the female reproductive system. Lactobacillus spp. is the most common bacteria within the reproductive tract. However, the protective role of Lactobacilli in the vagina has been well described in the literature, while it is still unknown what function Lactobacilli may have in the uterus. Moreover, new research shows that Lactobacillus spp. can have a role in miscarriage. However, both molecular and immunological mechanisms of host-Lactobacillus spp. interactions are not fully understood. Understanding these relationships will help address the importance and extent of the protective role of Lactobacillus spp. in miscarriage.     

New data on the enigmatic Ocruranus–Eohalobia group of Early Cambrian small skeletal fossils

Abstract: The Ocruranus–Eohalobia group, whose members were variously considered to be brachiopods, bivalves, chitons, tommotiids and coeloscleritophorans, are difficult to classify because of lack of morphological detail and evidence for skeletal reconstruction. New specimens from South China reveal more information about Ocruranus–Eohalobia and allow progress towards deciphering the skeletal reconstruction and phylogenetic affinity of this enigmatic group. Many specimens have a phosphatic inner and outer coat (mould) with empty space in between that resulted from dissolution of the original shell. Moreover, many of the internal moulds show a previously unknown type of shell microstructure that consisted of stacked layers of highly organized, acicular crystallites that radiated from the apex of the shell towards the aperture. The dissolved shell and needle‐like crystals suggest an original calcareous, probably aragonitic, shell mineralogy. A few specimens also show a polygonal texture in regions that suggests the shell had a thin, prismatic inner shell microstructure. Ocruranus and Eohalobia belong to the same skeleton, and we herein synonymize Eohalobia with the older Ocruranus. Moreover, new specimens from Meishucun reveal a third type of shell plate, similar in form and inferred placement to intermediate valves of chitons. Ocruranus is likely a mollusc, and possibly a member of the chiton stem lineage. If so, then the beginning of the known record of chitons would be extended back from late Cambrian (Saukia Zone; Furongian) to early Cambrian (Meishucunian; Series 1).