Textile dye decolorization using cyanobacteria

Cyanobacterial cultures isolated from sites polluted by industrial textile effluents were screened for their ability to decolorize cyclic azo dyes. Gloeocapsa pleurocapsoides and Phormidium ceylanicum decolorized Acid Red 97 and FF Sky Blue dyes by more than 80% after 26 days. Chroococcus minutus was the only culture which decolorized Amido Black 10B (55%). Chlorophyll a synthesis in all cultures was strongly inhibited by the dyes. Visible spectroscopy and TLC confirmed that color removal was due to degradation of the dyes.Revisions requested 10 November 2004/30 November 2004; Revisions received 16 November 2004/ 7 January 2005     

Beyond overpopulation: a comment on Zawistowski et al. and Salman et al

The intentional production and destruction each year of millions of companion animals is a sobering fact. The need for meaningful statistical data on this phenomenon is urgent. No less pressing, however, is the need for a conceptual framework to make sense of the empirical findings. The conventional focus on overpopulation is inadequate and places unnecessary limits on the way in which the problem is approached. I propose in its place a market-based model that takes seriously the role of consumer demand and considers the flaws and inefficiencies distorting the market for companion animals. Shifting attention to the choices consumers make in acquiring and discarding animal companions suggests new possibilities for change and provides a useful focal point for further empirical work.     

Grooming and social cohesion in primates: a comment on Grueter et al.

Grueter et al. have recently claimed that grooming time in primates is best explained by terrestriality, which they take to be a proxy for hygiene demand. We suggest that their results arise from a confound between terrestriality and other aspects of sociality, combined with a number of conceptual and sampling problems.     

Sperm length in sand martins Riparia riparia: a comment on Helfenstein et al

How long is a sand martin Riparia riparia spermatozoon? In a recent study, Helfenstein et al. (2008) presented data on the intraspecific variation in sperm length, swimming speed and longevity in this species and some interesting correlations between these variables. However, the reported sperm lengths are remarkably short for the species, which casts doubts about whether sperm total length has actually been measured and how the observed relationships should be interpreted.     

Fungal decolorization of dye wastewaters: a review

In recent years, there has been an intensive research on fungal decolorization of dye wastewater. It is becoming a promising alternative to replace or supplement present treatment processes. This paper examines various fungi, living or dead cells, which are capable of decolorizing dye wastewaters; discusses various mechanisms involved; reports some elution and regeneration methods for fungal biomass; summarizes the present pretreatment methods for increasing the biosorption capacity of fungal biomass; discusses the effect of various factors on decolorization.     

Technical comment on Adler et al. (2006): experimental design compromises conclusions

The conclusion that herbivory induces 'alkaloids' in nectar but not in leaves, is likely an artefact of using pot-bound plants and analytical procedures that only measure anabasine, a minor alkaloid representing 0.3% of the total alkaloids produced by Nicotiana tabacum.     

Caveats on the use of fossil calibrations for molecular dating: a comment on Near et al

We reassess a study on a fossil-calibrated molecular clock that provides a new method for evaluating the accuracy of calibration points. We address several pitfalls that molecular systematists should be aware of when calculating rates of molecular evolution based on fossil calibrations. These caveats involve the substantiation and accurate use of geologic dates, the inappropriate use of fixed calibration points, and the explicit and objective phylogenetic placement of fossil taxa. Paleontological data, like molecular data, should be treated with the utmost rigor.     

Study of dye decolorization in an immobilized laccase enzyme-reactor using online spectroscopy

Decolorization of textile dyes by a laccase from Trametes modesta immobilized on gamma-aluminum oxide pellets was studied. An enzyme reactor was equipped with various UV/Vis spectroscopic sensors allowing the continuous online monitoring of the decolorization reactions. Decolorization of the dye solutions was followed via an immersion transmission probe. Adsorption processes were observed using diffuse reflectance measurements of the solid carrier material. Generally, immobilization of the laccase does not seem to sterically affect dye decolorization. A range of commercial textile dyes was screened for decolorization and it was found that the application of this enzymatic remediation system is not limited to a certain structural group of dyes. Anthrachinonic dyes (Lanaset Blue 2R, Terasil Pink 2GLA), some azo dyes, Indigo Carmine, and the triphenylmethane dye Crystal Violet were efficiently decolorized. However, the laccase displayed pronounced substrate specificities when a range of structurally related model azodyes was subjected to the biotransformation. Azodyes containing hydroxy groups in ortho or para position relative to the azo bond were preferentially oxidized. The reactor performance was studied more closely using Indigo Carmine.     

Environmentally induced changes in carotenoid-based coloration of female lizards: a comment on Vercken et al

Colouration may either reflect a discrete polymorphism potentially related to life-history strategies, a continuous signal related to individual quality or a combination of both. Recently, Vercken et al. [J. Evol. Biol. (2007) 221] proposed three discrete ventral colour morphs in female common lizards, Lacerta vivipara, and suggested that they reflect alternative reproductive strategies. Here, we provide a quantitative assessment of the phenotypic distribution and determinants of the proposed colour polymorphism. Based on reflectance spectra, we found no evidence for three distinct visual colour classes, but observed continuous variation in colour from pale yellow to orange. Based on a 2-year experiment, we also provide evidence for reversible colour plasticity in response to a manipulation of the adult population sex ratio; yet, a significant portion of the colour variation was invariant throughout an adult female's life. Our results are thus in agreement with continuous colour variation in adults determined by environmental factors and potentially also by genetic factors.     

Microbial agents for decolorization of dye wastewater

Colored dye wastewater presents a formidable task for biological treatment. Depending on how it is generated, wide pH spans and high salt concentrations such as chloride ion often add to the difficulties. Systematic screening for dye decolorizing and/or degrading bioagents from soil and water samples discovered fungi which show dramatic color removal capability (Shen, et al., 1990). One example shows that up to 99% reduction of light absorption at characteristic wavelength of a red dye (200 mg/L) could be obtained within 48 hours. This ability does not appear to be specific toward dyes targeted for action. It clarifies, often beyond detection by naked eyes, a repertoire of colored wastewater samples. These results appeared to be insensitive to wide variations in pH and salt concentration and, they are not limited to one particular fungal species or genus either upon further investigation. This dye adsorption mechanism may be of great significance in uncovering new methods for bio-removal or bio-recovery of dye substances in wastewater.     

STEMI time delays: a clinical perspective: Editorial comment on the article by Verweij et al.

STEMI time delays have been introduced as a performance indicator or marker of quality of care. As they are only one part of a very complex medical process, one should be aware of concomitant issues that may be overlooked or even be more important with regard to clinical outcome of STEMI patients. In this overview we try to summarise the most important ones.