Analysis of viability and cell types of macroalgal protoplasts using flow cytometry

The ability to rapidly distinguish viable sub-populations of cells within populations of macroalgal protoplast isolations was demonstrated using flow cytometry. Viable protoplasts from Ulva sp. and Porphyra perforata J. Ag. were distinguished from non-viable protoplasts based on differential fluorescein accumulation. The identities of cortical and epidermal protoplasts from Macrocystis pyrifera (L.) C. Ag. were inferred based on light-scattering and chlorophyll a autofluorescence. Three cell types could be distinguished among protoplasts released from thalli of P. perforata based on chlorophyll a and phycoerythrin autofluorescence. Mixed protoplast populations of Ulva sp. and P. perforata were also discernable based on relative chlorophyll a and phycoerythrin autofluorescence. The ability to screen heterogenous protoplast populations rapidly, combined with the cell sorting capabilities of many flow cytometers, should prove valuable for seaweed biotechnology.     

Characteristics of a human epidermal squamous carcinoma cell line at different extracellular calcium concentratrions

A continuous line derived from a human skin squamous cell carcinoma has been grown in media of high, normal and low Ca²⁺ concentrations. The growth rate was unaffected by the Ca²⁺ levels even though morphological changes were observed. Desmosomes were absent at low Ca²⁺ and areas of cell piling were observed at high Ca²⁺. Cell protein staining patterns on polyacrylamide gels were identical for cells grown at the three Ca²⁺ levels. The variations were minor for the glycoproteins reacted with ¹²⁵I-conA. Lactoper-oxidase iodination revealed changes in cell surface proteins, most markedly in the emergence of new proteins at high Ca²⁺.     

Some adaptations between Danaus plexippus and its food plant, with notes on Danaus chrysippus and Euploea core (Insecta: Lepidoptera)

Behaviour of the egg-laying Monarch in captivity suggests that the concentration and quality of cardiac glycosides in the food plant are not important oviposition cues. The presence of eggs (as previously noted by Urquhart, 1960) and larvae feeding on the food plant, act as mild deterrents.
The butterfly's emetic potency (see Table XIII(a)) can sometimes surpass that of the leaves of the host plant itself. Unidentified factors, providing the internal plant environment, are more important as cardiac glycoside storage stimulants than either the quantity or quality of the cardenolides present. In the laboratory D. plexippus oviposited preferentially on a plant with relatively low cardiac glycoside content, but which produced the most powerfully protected (emetic) adult.
Metabolic changes during the pharate pupal stage, but also, in the case of Euploea core , in the larval fifth instar, rather than larval sequestration, may account for the major increase or decrease in butterfly toxicity compared with that of the food plant.
Temperature does not affect the storage of cardenolides except indirectly by altering metabolic rate. There is no evidence to support the concept that current "physiological cost" of cardenolide storage is high. Like the toad, this butterfly can be assumed to have evolved an enzvmatic system well adjusted to the presence of cardenolides in its bodv tissues.     

Beyond ecosystem modeling: A roadmap to community cyberinfrastructure for ecological data‐model integration

In an era of rapid global change, our ability to understand and predict Earth's natural systems is lagging behind our ability to monitor and measure changes in the biosphere. Bottlenecks to informing models with observations have reduced our capacity to fully exploit the growing volume and variety of available data. Here, we take a critical look at the information infrastructure that connects ecosystem modeling and measurement efforts, and propose a roadmap to community cyberinfrastructure development that can reduce the divisions between empirical research and modeling and accelerate the pace of discovery. A new era of data‐model integration requires investment in accessible, scalable, and transparent tools that integrate the expertise of the whole community, including both modelers and empiricists. This roadmap focuses on five key opportunities for community tools: the underlying foundations of community cyberinfrastructure; data ingest; calibration of models to data; model‐data benchmarking; and data assimilation and ecological forecasting. This community‐driven approach is a key to meeting the pressing needs of science and society in the 21st century.     

Functional anatomy of scent glands in Paranemastoma quadripunctatum (Opiliones,Dyspnoi, Nemastomatidae)

The morphological organization and functional anatomy of prosomal defensive (scent) glands in Paranemastoma quadripunctatum, a representative of the dyspnoid harvestmen, was investigated by means of histological semithin sections, software‐based 3D‐reconstruction and scanning electron microscopy. Scent glands comprise large, hollow sacs on either side of the prosoma, each of these opening to the outside via one orifice (ozopore) immediately above coxa I. In contrast to the situation known from laniatorean, cyphophthalmid and some eupnoid Opiliones, ozopores are not exposed but hidden in a depression (atrium), formed by a dorsal integumental fold of the carapace and the dorsal parts of coxae I. Glandular sacs are connected to ozopores via a short duct which is equipped with a specific closing mechanism in its distal part: A layer of modified epidermal cells forms a kind of pad‐like tissue, surrounding the duct like a valve. Several muscles attached to the anterior parts of the glandular reservoir and to the epithelial pad may be associated with ozopore‐opening. The actual mechanism of secretion discharge seems to be highly unusual and may be hypothesized on the basis of corroborating data from behavioral observations, scent gland anatomy and secretion chemistry as follows: Enteric fluid is considered to be directed towards the ozopores via cuticular grooves in the surface of the coxapophyses of legs I. Then, the fluid is sucked into the anterior part of the scent gland reservoirs by the action of dorsal dilator muscles that widen the reservoir and produce a short‐term negative pressure. After dilution/solution of the naphthoquinone‐rich scent gland contents, a secretion‐loaded fluid is thought to be discharged with the help of transversal compressor muscles. This is the first detailed study on the functional anatomy of scent glands and the mechanisms of secretion discharge in the Dyspnoi. J. Morphol. 2011. © 2011 Wiley‐Liss, Inc.     

Microbial catalysis in bioelectrochemical technologies: status quo, challenges and perspectives

Over the past decade, microbial electrochemical technologies, originally developed from an interesting physiological phenomenon, have evolved from a rush of initiatives for sustainable bioelectricity generation to a multitude of specialized applications in very different areas. Genetic engineering of microbial biocatalysts for target bioelectrochemical applications like biosensing or bioremediation, as well as the discovery of entirely new bioelectrochemical processes such as microbial electrosynthesis of commodity chemicals, open up completely new possibilities. Where stands this technology today? And what are the general and specific challenges it faces not only scientifically but also for transition into commercial applications? This review intends to summarize the recent advances and provides a perspective on future developments.     

Effects of grass species and grass growth on atmospheric nitrogen deposition to a bog ecosystem surrounded by intensive agricultural land use

We applied a ¹⁵N dilution technique called “Integrated Total Nitrogen Input” (ITNI) to quantify annual atmospheric N input into a peatland surrounded by intensive agricultural practices over a 2-year period. Grass species and grass growth effects on atmospheric N deposition were investigated using Lolium multiflorum and Eriophorum vaginatum and different levels of added N resulting in increased biomass production. Plant biomass production was positively correlated with atmospheric N uptake (up to 102.7 mg N pot⁻¹) when using Lolium multiflorum. In contrast, atmospheric N deposition to Eriophorum vaginatum did not show a clear dependency to produced biomass and ranged from 81.9 to 138.2 mg N pot⁻¹. Both species revealed a relationship between atmospheric N input and total biomass N contents. Airborne N deposition varied from about 24 to 55 kg N ha⁻¹ yr⁻¹. Partitioning of airborne N within the monitor system differed such that most of the deposited N was found in roots of Eriophorum vaginatum while the highest share was allocated in aboveground biomass of Lolium multiflorum. Compared to other approaches determining atmospheric N deposition, ITNI showed highest airborne N input and an up to fivefold exceedance of the ecosystem-specific critical load of 5–10 kg N ha⁻¹ yr⁻¹.