On the Photosynthetic Potential in the Very Early Archean Oceans

In this work we apply a mathematical model of photosynthesis to quantify the potential for photosynthetic life in the very Early Archean oceans. We assume the presence of oceanic blockers of ultraviolet radiation, specifically ferrous ions. For this scenario, our results suggest a potential for photosynthetic life greater than or similar to that in later eras/eons, such as the Late Archean and the current Phanerozoic eon.     

Isolation and characterization of microsatellites in Pacific white shrimp Penaeus (Litopenaeus) vannamei

Five polymorphic microsatellite loci were characterized for Penaeus (Litopenaeus) vannamei. Loci were isolated using a partial Sau3A1 genomic library by the sequencing of randomly selected clones and by a biotinylated (CT)₁₀ and (GT)₁₀ probes screening procedure. The last strategy resulted in the most useful data. About 40% of the clones showed a previously reported satellite/microsatellite (PVS1), reducing the chance of finding new microsatellite regions. Whereas two of the microsatellite loci with more than 10 alleles will be useful for mating analysis in a breeding program, the others might prove useful for population genetic studies.     

Lactose-containing starburst dendrimers: influence of dendrimer generation and binding-site orientation of receptors (plant/animal lectins and immunoglobulins) on binding properties.

Starburst glycodendrimers offer the potential to serve as high-affinity ligands for clinically relevant sugar receptors. In order to define areas of application, their binding behavior towards sugar receptors with differential binding-site orientation but identical monosaccharide specificity must be evaluated. Using poly(amidoamine) starburst dendrimers of five generations, which contain the p-isothiocyanato derivative of p-aminophenyl-beta-D-lactoside as ligand group, four different types of galactoside-binding proteins were chosen for this purpose, i.e., the (AB)(2)-toxic agglutinin from mistletoe, a human immunoglobulin G fraction, the homodimeric galectin-1 with its two binding sites at opposite ends of the jelly-roll-motif-harboring protein and monomeric galectin-3. Direct solid-phase assays with surface-immobilized glycodendrimers resulted in obvious affinity enhancements by progressive core branching for the plant agglutinin and less pronounced for the antibody and galectin-1. High density of binding of galectin-3 with modest affinity increases only from the level of the 32-mer onwards points to favorable protein-protein interactions of the monomeric lectin and a spherical display of the end groups without a major share of backfolding. When the inhibitory potency of these probes was evaluated as competitor of receptor binding to an immobilized neoglycoprotein or to asialofetuin, a marked selectivity was detected. The 32- and 64-mers were second to none as inhibitors for the plant agglutinin against both ligand-exposing matrices and for galectin-1 on the matrix with a heterogeneous array of interglycoside distances even on the per-sugar basis. In contrast, a neoglycoprotein with the same end group was superior in the case of the antibody and, less pronounced, monomeric galectin-3. Intimate details of topological binding-site presentation and the ligand display on different generations of core assembly are major operative factors which determine the potential of dendrimers for applications as lectin-targeting device, as attested by these observations.     

Sterilization of Plants for Phytoremediation Studies by Bleach Treatment

Bleach treatment of plants was studied as a simple alternative to axenic tissue cultures for demonstrating phytodegradation of aqueous and gas-phase environmental contaminants. Parrotfeather (Myriophyllum aquaticum), spinach (Spinacia oleracea), and wheat (Triticum aestivum) were exposed to 0.525% NaC10 solutions for 15 s, then rinsed in deionized water. Plate counts indicated that 97 to 100% of viable bacteria were removed from parrotfeather and spinach. Transformation rates for 2,4,6-trinitrotoluene (TNT) by bleached and untreated parrotfeather were virtually identical. Similarly, treated and untreated spinach, wheat heads, and wheat leaves removed methyl bromide (MeBr) from air at the same rates. However, wheat root with attendant adhering soil was rendered inactive by bleach treatment. Parrotfeather roots examined by dissecting microscope and by electron microscope showed no significant damage caused by bleach treatment.     

A Spatially Explicit Model of Synchronization in Fiddler Crab Waving Displays

Fiddler crabs (Uca spp., Decapoda: Ocypodidae) are commonly found forming large aggregations in intertidal zones, where they perform rhythmic waving displays with their greatly enlarged claws. While performing these displays, fiddler crabs often synchronize their behavior with neighboring males, forming the only known synchronized visual courtship displays involving reflected light and moving body parts. Despite being one of the most conspicuous aspects of fiddler crab behavior, little is known about the mechanisms underlying synchronization of male displays. In this study we develop a spatially explicit model of fiddler crab waving displays using coupled logistic map equations. We explored two alternative models in which males either direct their attention at random angles or preferentially toward neighbors. Our results indicate that synchronization is possible over a fairly large region of parameter space. Moreover, our model was capable of generating local synchronization neighborhoods, as commonly observed in fiddler crabs under natural conditions.     

Lipid quantitation in formalin-fixed liver sections

We describe a simple, sensitive, and quantitative procedure for measurement of triglycerides and protein contents in formalin-fixed liver sections. The method can detect as little as 0.27 microgram of triglycerides per mg of protein. It is based on selective binding of Sudan IV and Fast Green FCF to fat and total proteins, respectively, and their sequential elution with solvents. Sudan IV is eluted readily with acetone and Fast Green with NaOH-methanol, and the absorbances obtained at 500 and 610 nm can be used to determine the amount of triglycerides and total protein. The color equivalence for Fast Green was obtained after destaining the sections and measuring the protein contents by micro-Kjeldahl analysis. The color equivalence of Sudan IV was estimated by determining the triglyceride content in liver homogenates by an enzymatic procedure and then measuring the amount of dye bound to multiple fixed sections. There was a strong linear correlation between the triglyceride content as determined chemically and that obtained using the equivalence colors (r2 = 0.98). This method is useful to measure fat content in tissue samples and could be applied to evaluate the progression of liver disease.     

The effect of photoperiod on male sexual behaviour in a north adriatic strain of the migratory locust

The Panzano strain of the migratory locust, Locusta migratoria, originating from North Italy, was used for laboratory experiments under conditions of either 12 or 16 hrs illumination per day. Preliminary experiments demonstrated that in this strain 16 hrs day-length led to delayed and reduced egg-laying, while 12 hrs day-length induced early and intensive oviposition. In subsequent experiments sexual behaviour of males kept under either regime of the photoperiod was observed in the presence of receptive females. Kept under 12 hrs day-length, males exhibited vigorous sexual behaviour, approximately at the same level of intensity from the 2nd till the 5th–6th week of the experiment. In contrast, under 16 hrs illumination the intensity of male sexual behaviour gradually increased from the 2nd till the 9th–10th week. Thus, photoperiod affected the intensity of male sexual behaviour in this strain.

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Résumé La souche Panzano de Locusta migratoria provenant du nord de l'Italie, a été utilisée pour des expériences de laboratoire sous des conditions d'éclairement de 12 h ou 16 h par jour. Des expériences préliminaires avaient montré que chez cette souche, une durée d'éclairement de 16 h par jour retardait et réduisait la ponte, tandis qu'avec un éclairement de 12 h celle-ci était précoce et intense. Dans les expériences ultérieures on a observé le comportement sexuel de mâles, en présence de femelles réceptrices, alors qu'ils sont soumis à l'une ou l'autre de ces deux photopériodes. Maintenus sous une photopériode de 12 h les mâles montraient un comportement sexuel intense, se maintenant à peu près au même niveau de la seconde semaine jusqu'à la 5ème ou 6ème semaine de l'expérience. Au contraire, avec un éclairement de 16 h, l'intensité du comportement sexuel s'accroissait graduellement de la seconde semaine jusqu'à la 9ème ou 10ème semaine. Ainsi, la photopériode modifiait l'intensité du comportement sexuel mâle chez cette souche de Locusta migratoria.