A convenient affinity chromatography-based purification of firefly luciferase

A method is described for purifying luciferase from firefly lanterns in very good yield. The enzyme was extracted from Photinus lanterns, dialyzed, and further purified by affinity chromatography with 6-aminohexanoic acid-Sepharose 4b benzylamine. Fractions containing luciferase activity were pooled, concentrated by ultrafiltration, and crystallized by dialysis against a low-ionic-strength buffer. The crystalline enzyme appears to be homogeneous by sodium dodecyl sulfate-gel electrophoresis. The entire protocol described was conveniently performed in less than 3 days and yielded 6.2 mg of enzyme from 2.2 g of firefly lanterns. Furthermore, the affinity column employed can be reused at least five times without appreciable loss of binding capacity. Luciferase was chromatographed with several other affinity gels and the results are compared. It appears that 6-aminohexanoic acid-Sepharose 4b benzylamine does not function as a true bioaffinity gel, but rather as a hydrophobic interaction support.     

Female rhesus macaques discriminate unfamiliar paternal sisters in playback experiments: support for acoustic phenotype matching

Widespread evidence exists that when relatives live together, kinship plays a central role in shaping the evolution of social behaviour. Previous studies showed that female rhesus macaques (Macaca mulatta) recognize familiar maternal kin using vocal cues. Recognizing paternal kin might, however, be more difficult as rhesus females mate promiscuously during the possible conception period, most probably concealing paternity. Behavioural observations indicate that semi free-ranging female rhesus macaques prefer to associate with their paternal half-sisters in comparison to unrelated females within the same group, particularly when born within the same age cohort. However, the cues and mechanism/s used in paternal kin discrimination remain under debate. Here, we investigated whether female rhesus macaques use the acoustic modality to discriminate between paternal half-sisters and non-kin, and tested familiarity and phenotype matching as the underlying mechanisms. We found that test females responded more often to calls of paternal half-sisters compared with calls of unrelated females, and that this discrimination ability was independent of the level of familiarity between callers and test females, which provides, to our knowledge, the first evidence for acoustic phenotype matching. Our study strengthens the evidence that female rhesus macaques can recognize their paternal kin, and that vocalizations are used as a cue.     

Biomass and nutritive value of Spirulina (Arthrospira fusiformis) cultivated in a cost-effective medium

Introduction

Cultivation of spirulina at commercial-scales relies on analytical grade–based media, which are expensive and so are the product.

Purpose

This study assessed the biomass, proximate composition, and other useful compounds in Spirulina (Arthrospira fusiformis) produced with a cost-effective culture medium (LCMA), and the results were compared with those from a standard Zarrouk medium–grown spirulina.

Methods

The LCMA medium was formulated by using a commercial NPK10-20-20 fertilizer as a source of the three major nutrients for spirulina growth, and other three ingredients from Zarrouk medium. The experiment was conducted for 28 days in the glass aquaria under indoor conditions. Standard analytical methods were applied for the determination of proximate composition, chlorophyll, minerals, and vitamins in the spirulina biomass.

Result

The LCMA medium showed the best growth conditions by accumulating higher chlorophyll content (0.99 ± 0.02%) and dry weight (0.75 ± 0.01 g/100 ml) as well as attaining higher optical density (2.06 at day 15) earlier than the Zarrouk medium. The results of the proximate analysis for spirulina cultured in the LCMA medium were of good quality, with the protein contributing more than 50% of its dry matter. It was further noticed that the LCMA was an ideal medium for optimization of vitamins and some minerals since it recorded a significant amount of most of the analyzed vitamins together with the minerals sodium and potassium compared with the Zarrouk medium.

Conclusion

It is suggested that LCMA medium could be used as the alternative and cheap medium for maximization of biomass and production of useful biochemical compounds in spirulina species.