A counterselection method for Lactococcus lactis genome editing based on class IIa bacteriocin sensitivity

Applied Microbiology and Biotechnology - In this paper, we present a new counterselection method for deleting fragments from Lactococcus lactis chromosome. The method uses a non-replicating plasmid...     

Immunoelectron microscopic localization of carbonic anhydrase III in rat skeletal muscle

Summary The subcellular distribution of carbonic anhydrase III in rat soleus and vastus lateralis muscles was studied using an immunogold technique. The enzyme protein was found to be distributed diffusely in the cytoplasm of skeletal muscle cells. Red skeletal muscle (mainly type I fibers) revealed very strong immunogold staining whereas in white muscle (mainly type II fibers) gold particles were almost completely absent. No immunoreaction was observed in mitochondria or in other intracellular organelles.     

The effect of filters on aseptic pipetting lifetime of mechanical and electronic pipettors and carryover during pipetting

The aseptic pipetting lifetime of air displacement pipettors during serial pipetting was investigated. When a Micrococcus luteus ^T culture was pipetted using no filter, less than 100 pipettings were required to contaminate the interiors of both mechanical and electronic pipettors with more than 10³ cfu (n = 1890 pipettings). When a filter was placed in the pipettor tip cone, the sterility of the pipettor barrel was maintained for more than 500 pipettings (n = 2620) or 50–250 pipettings (n = 2520), depending on the filter type used. When a radioactive liquid or plasmid DNA was pipetted using no filter, contamination of the pipettor barrel occurred within less than 100 pipettings. A filter placed in the pipettor tip cone protected the interior of the pipettors against radioactive contamination for more than 250 pipettings and against DNA contamination for more than 500 pipettings. A pipettor barrel contaminated with M. luteus ^T caused carryover in 13% of the pipetting series. When a SCF filter was placed in the tip cone, no carryover was observed within 2620 pipettings. A tip cone filter replaced at intervals of 50–250 (polyethylene filter) or 500 (SCF filter) pipettings will protect the pipettor barrel from contamination and the samples from carryover.     

Effects of training and anabolic steroids on collagen synthesis in dog heart.

The effects of endurance training and anabolic steroid (Methandienone 1.5 mg.kg-1 p. o. daily) and their combination on regional collagen biosynthesis and concentration in the hearts of male beagle dogs were studied by measuring prolyl 4-hydroxylase (PH) activity and hydroxyproline (HYP) concentration. The PH (P less than 0.05) and HYP (P less than 0.05) were both greater in the subendocardinal layer than in the subepicardium (EPI) of the left ventricular wall in controls, whereas opposite gradients (P less than 0.05) were observed in the right ventricle. Endurance exercise caused an increase of PH activity in EPI of the left ventricular wall (P less than 0.01). The HYP concentration increased in both layers of the right ventricle in the exercise plus steroid group (P less than 0.05). The results suggest that transmural differences exist in the rate of collagen synthesis and concentration in canine cardiac ventricles and that endurance exercise may accelerate collagen synthesis in EPI of the left ventricle and the combination of exercise and anabolic steroid causes an increase in collagen concentration in the right ventricular wall.