Design and evolution of new catalytic activity with an existing protein scaffold

The design of enzymes with new functions and properties has long been a goal in protein engineering. Here, we report a strategy to change the catalytic activity of an existing protein scaffold. This was achieved by simultaneous incorporation and adjustment of functional elements through insertion, deletion, and substitution of several active site loops, followed by point mutations to fine-tune the activity. Using this approach, we were able to introduce beta-lactamase activity into the alphabeta/betaalpha metallohydrolase scaffold of glyoxalase II. The resulting enzyme, evMBL8 (evolved metallo beta-lactamase 8), completely lost its original activity and, instead, catalyzed the hydrolysis of cefotaxime with a (kcat/Km)app of 1.8 x 10(2) (mole/liter)(-1) second(-1), thus increasing resistance to Escherichia coli growth on cefotaxime by a factor of about 100.     

Multibiomarker response shows how native and non‐native freshwater bivalves differentially cope with heat‐wave events

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Detecting reproductive system abnormalities of broiler breeder roosters at different ages

The objective of this study was to detect the reasons of rooster's fertility decrease at 50 weeks of age. Therefore, the reproductive system of broiler breeder roosters was laparoscopic, macroscopic and histopathology evaluated, and a comparison of the anatomical aspect with the sperm analysis and birds’ age was realized. Cobb roosters (n = 59) were distributed into two groups (30 and 50 weeks). Evaluations were performed with laparoscopy, macroscopy and histopathology, and seminal quality, blood serum testosterone concentration and weight were also determined. The old roosters presented smaller testicle size, higher intensity epididymal lithiasis and lower testicle sperm production, compared to the young roosters. The use of the endoscope could easily distinguish a normal‐sized testicle than an atrophic one. Four old roosters with severe testicular atrophy did not show spermatogenesis, although three still had sperm in the ejaculate. This would falsely indicate a wrong diagnosis of normal fertility before the testicular atrophy took place. In conclusion, in addition to the weight increase with age, the testicular atrophy and impairment of sperm production seemed to be the main reason to the decrease in the rooster's fertility at 50 weeks of age. Therefore, the use of the laparoscopy as a way to detect the roosters with testicular atrophy before 50 weeks of age and their removal from them flock could be useful as a diagnostic tool to prevent the birds’ fertility loss.     

Animal-based organic nutrition induces comparable fruit quality to that of inorganic fertigation in soilless-grown grape tomato

The aim of the present study was to determine the effect of animal-based organic nutrition and environmental parameters on tomato fruit quality, as well as to establish relations among colour and morphological values performed by the Tomato Analyzer (TA) software application. Organic tomato fruits produced by three organic nutrient solutions, which consisted of different mixtures of several OMRI certified nitrogen fertilizers and one inorganic nutrient solution (Steiner’s solution) as the control, were evaluated for their polyphenol and carotenoid content. We used Tomato Analyzer (TA) to evaluate fruit size and shape. Moreover, we implemented a digital image analysis tool, Color Test (CT), as part of the TA software application to collect and analyse fruit colour parameters. The application of organic fertilizers positively affected the total hydrolysable and condensed polyphenols of tomato fruits compared to the control. The high air temperature (>30°C) and sub-optimal light intensity negatively affected the carotene content of tomato fruits, as well as their morphological and colour attributes. Plants fed with organic solutions containing ASA + ASB + NK2SO4 showed comparable morphology and fruit colour attributes to those of the control plants that received Steiner’s nutrient solution. The results indicated that the application of organic fertilizers positively affected the total hydrolysable and condensed polyphenols of tomato fruits compared to the control. Plants fed with the Steiner’s nutrient solution exhibited the highest carotenoid content in tomato fruits. Organically produced tomatoes through animal-based fertilizer application displayed similar fruit morphology and colour attributes compared to conventionally produced tomatoes.