Review – Interactions between diatoms and stainless steel: focus on biofouling and biocorrosion

There is a considerable body of information regarding bacterially enhanced corrosion, however, this review focuses on diatoms (unicellular algae) whose contribution to biocorrosion is less well studied. The reasons why diatoms have been neglected in studies of biocorrosion in natural waters are discussed and the question whether diatoms should be considered as inert with respect of electrochemical processes is considered. A particular focus is given to the case of stainless steels (SS), which are widely used in variety of applications in natural waters. Basic information on the cell biology of diatoms is included in the review, particularly with respect to their ability to ‘sense’ and adhere to surfaces. Investigations at the nanoscale are reviewed as these studies provide information about the behavior of cells at interfaces. Recent advances include the use of atomic force microscopy (AFM), although only a few studies have been applied to diatoms. Regarding the electrochemical behavior of SS, the mechanisms by which diatoms influence the potential ennoblement process is discussed. Such studies reveal the association of diatoms, in addition to bacteria, with biocorrosion processes.     

Fuchsine or magenta: the second most famous aniline dye. A short memoir on the 150th anniversary of the first commercial production of this well known dye

During the mid-nineteenth century, it was learned that the distillation of coal tar yielded a mixture of benzene and toluene that could be used for the manufacture of “anilines.” Oxidation with dichromate led to the first synthetic aniline dye, mauveine. The second aniline dye, a crimson red color, now is named fuchsine or magenta. This dye was prepared using the same starting material, but different oxidants, e.g., tin chloride, mercury nitrate, arsenic acid, and nitrobenzene. Unlike mauveine, which is now a chemical curiosity, fuchsine is still in use as a biological stain, especially in Schiff's reagent for detecting aldehydes, industrially as a dye in coloring various materials from textile fibers to ball point pen inks, analytically as a visualization agent for thin layer chromatography, and as an antifungal agent.     

Quirks of dye nomenclature. 12. Victoria’s rainbow

ABSTRACT

The identities of 18 dyes whose names begin with “Victoria” are described using their chemical structures, names and numerical identifiers. All are synthetic dyes originally synthesized in Germany during the late 19^th century as colorants for textiles. Brief manufacturing details are included. All the colors of the rainbow are represented except indigo. Unusual properties including explosive tendency or toxicity are noted. Some of the applications as stains and for food coloring, anti-obesity medication and pigments for ball pen inks also are discussed     

THE GLUCOSE TRANSPORT SYSTEM OF AMPHORA COFFEAEFORMIS (BACILLARIOPHYCEAE)1

Amphora coffeaeformis (Ag.) Kütz. var. perpusilla (Grun.) Cleve took up glucose by an inducible transport system. The system was induced by d -fructose, d -mannose, as well as glucose. Some d -pentoses also induced a glucose uptake system but it may not be the same one as that induced by hexose. d -fructose, d -mannose and 2-deoxy-d -glucose inhibited 2 mM glucose uptake at equimolar concentration, but d -pentoses did not. The uptake system decayed in ca. 5 h in the absence of glucose. The half-saturation constant for uptake, K₈ was ca. 0.1 mM glucose with a maximum uptake rate, V_max= 0.4 nmol/10⁶ cells-min^?1.     

The partial stream sampling assumption in intestinal perfusion studies

During the past several years, the technique ofin vivo intestinal perfusion with partial stream sampling has been increasingly widely used to gather information on intestinal absorptive processes in man. The basic technique involves infusion of test solution through a proximal opening; and aspiration of samples through one or more distal openings a fixed distance apart. Samples are analyzed for test solute concentrations; from such sample data, conclusions are drawn concerning alterations in stream concentrations between the sampling sites. An underlying assumption for the validity of such a method is: that sample concentrations are the same as average stream concentrations. This assumption has not previously been precisely stated. A precise statement of it is given here, together with an analytic proof of conditions necessary and sufficient for its validity. A brief verbal comment is included to clarify the practical meaning of the analytic statement.     

Quirks of dye nomenclature. 2. Congo red

The history, origin, identity, chemistry and uses of Congo red are described. Originally patented in 1884, Congo red soon found applications in dyeing cotton, as a pH indicator for chemists and as a biological stain. Unlike the majority of the 19th century synthetic dyes, it still is available commercially.     

Out of Africa and back again: nested cladistic analysis of human Y chromosome variation

We surveyed nine diallelic polymorphic sites on the Y chromosomes of 1,544 individuals from Africa, Asia, Europe, Oceania, and the New World. Phylogenetic analyses of these nine sites resulted in a tree for 10 distinct Y haplotypes with a coalescence time of approximately 150,000 years. The 10 haplotypes were unevenly distributed among human populations: 5 were restricted to a particular continent, 2 were shared between Africa and Europe, 1 was present only in the Old World, and 2 were found in all geographic regions surveyed. The ancestral haplotype was limited to African populations. Random permutation procedures revealed statistically significant patterns of geographical structuring of this paternal genetic variation. The results of a nested cladistic analysis indicated that these geographical associations arose through a combination of processes, including restricted, recurrent gene flow (isolation by distance) and range expansions. We inferred that one of the oldest events in the nested cladistic analysis was a range expansion out of Africa which resulted in the complete replacement of Y chromosomes throughout the Old World, a finding consistent with many versions of the Out of Africa Replacement Model. A second and more recent range expansion brought Asian Y chromosomes back to Africa without replacing the indigenous African male gene pool. Thus, the previously observed high levels of Y chromosomal genetic diversity in Africa may be due in part to bidirectional population movements. Finally, a comparison of our results with those from nested cladistic analyses of human mtDNA and beta-globin data revealed different patterns of inferences for males and females concerning the relative roles of population history (range expansions) and population structure (recurrent gene flow), thereby adding a new sex-specific component to models of human evolution.      

Purification of a protein from Bacillus thuringiensis toxic to larvae of lepidoptera

The protein toxin of the parasporal body or crystal of Bacillus thuringiensis (Mattés isolate) has been purified severalfold by a combination of Sephadex G-200 gel filtration and ammonium sulphate precipitation. It has been shown that the use of highly alkaline conditions for dissolution of the crystals does not lead to serious artifacts. The crystal toxin has been shown to be quantitatively related to the crystal antigen. It is possible that there is a second distinct toxin present in the crystal and this too can be detected by its antigenic reaction. Purified toxic protein has been hydrolysed in vitro by regurgitated Pieris brassicae gut enzymes, chymotrypsin, trypsin and subtilisin. In each case the digest contained a product that was still antigenic, had mol.wt. about 40000 and was toxic to P. brassicae larvae. Smaller toxic molecules (mol.wt. approx. 10000) that did not react as antigens were also produced by proteolysis. It is possible that these smaller molecules were hydrolytic products of the larger digestion product.     

Quirks of dye nomenclature. 6. Malachite green

Malachite green was discovered independently by two researchers in Germany in the 19^th century and found immediate employment as a dye and a pigment. Subsequently, other uses, such as staining biological specimens, emerged. A much later application was the control of fungal and protozoan infections in fish, for which the dye remains popular, although illegal in many countries owing to a variety of toxicity problems. In solution, malachite green can exist as five different species depending on the pH. The location of the positive charge of the colored cation on a carbon atom or a nitrogen atom is still debated. The original names of this dye, and their origins, are briefly surveyed.     

Quirks of dye nomenclature. 5. Rhodamines

Rhodamines were first produced in the late 19^th century, when they constituted a new class of synthetic dyes. These compounds since have been used to color many things including cosmetics, inks, textiles, and in some countries, food products. Certain rhodamine dyes also have been used to stain biological specimens and currently are widely used as fluorescent probes for mitochondria in living cells. The early history and current biological applications are sketched briefly and an account of the ambiguities, complications and confusions concerning dye identification and nomenclature are discussed.