Comparative study of membranes of Streptococcus faecalis and Micrococcus lysodeikticus

A comparative study of ultrastructure and IR-spectroscopy of osmotic shock membranes from cells of glycolyzing (Streptococcus faecalis) and respiring (Micrococcus lysodeikticus) bacteria, was made. The S. faecalis and M. lysodeikticus membranes differ in their cross-section. Treatment of the preliminary washed membranes of S. faecalis and M. lysodeikticus with a low ionic strength solution removes 40% and 70% of their proteins respectively, decreases the membrane cross-section but does not change their fracture faces. Pre-cooling of the membrane suspensions within the temperature range of +5 degrees-10 degrees results in the appearance of large smooth areas on S. faecalis membrane fracture faces, but does not affect the ones of M. lysodeikticus membrane. Treatment of the washed suspensions with Triton X-100 results in the appearance of drastic changes of S. faecalis membrane fracture faces and does not change the fracture faces of M. lysodeikticus membranes; treatment by the detergent does not alter the IR-spectroscopy of membranes of both bacteria. Treatment of S. faecalis and M. lysodeikticus membranes with high temperature irreversibly changes the structure of 20% and 40% of protein components respectively,, but does not affect the distribution of the subparticles on their fracture faces. It is assumed that the differences found are determined by the composition of lipid components of the membranes studied and that the amount of proteins closely bound with lipids in the membranes of S. faecalis is likely to be greater than that of M. lysodeikticus membranes.     

Steroid hormones in erysipelas

Deep neck infection has ominous implications if not detected and treated in an early stage. The anatomic relationships of head and neck spaces encourage spread of infection. Immediate hospitalization and constant monitoring of the patient after diagnosis are mandatory.     

Neurophysiologic study of sleep in infants with cerebral palsy

With the aid of a polygraphical study of day sleep in infants with cerebral palsy it was possible to demonstrate in many cases changes of qualitative characteristics of the stages of sleep with disorders of normal dynamics in the EEG, motor and vegetative signs. The authors detected a certain correlation between the degree of such changes and the severity of the clinical symptomatology, as well as a possibility of changes in expression of the pathology of sleep at different stages of the disease, sometimes with an increase of this pathology.     

Thermostability of the rhodopsins of several fish in the Sea of Japan

Studies have been made on thermal denaturation of rhodopsin in hotoreceptive membranes of retinal rods of some Japan Sea fishes--Podthecus sp., Enophrys diceraus, Myoxocephalus stelleri, Pleurogrammus monopterygius, Sebastichthys trivittatus, Pheumatophorus japonicus, Gadus morhua, Theragia chaloogramma, Eleginus gracilis and Lepidopsetta herzensteini. It was shown that visual pigments of the species studied significantly differ in their thermostability, whereas with respect to their spectral properties they are rather similar (absorbtion maxima lie near 500 nm). Positive correlation between the thermostability level of rhodopsins and the environmental temperature of the species was found.     

Tuning of an electrospray ionization source for maximum peptide-ion transmission into a mass spectrometer

We describe assembly and optimization of a continuous flow nanoelectrospray source for high-performance analysis on a routine basis. It is derived from an inJection adaptable Fine Ionization Source ("JaFIS"), previously shown to be durable and easy to use (Geromanos, S.; et al. Rapid Commun. Mass Spectrom. 1998, 12, 551-556) and now modified for maximum sensitivity. Proper design, manufacturing, and quality control of spray needles with specific orifice diameters, in combination with precisely controlled helium backpressure and applied voltage, enable stable flows at 1-2 nL/min. Needle positioning and ion spray potential are hereby exceedingly important, as shifts by 0.5 mm or 25 V, respectively, cause significant reduction in signal strength. In addition to prolonged analysis times, ultralow flows also yield higher sensitivity, the result of an improved "overall ion transfer efficiency" measured to be approximately 5% at 1.6 nL/min. Used in combination with a "microtip" (Erdjument-Bromage, H.; et al. J. Chromatogr. A 1998, 826, 167-181), the optimized JaFIS implements infusion-style ESI-MS at sensitivities approaching capillary LC-MS. Spraying times in excess of 20 h allow for any number of tandem mass spectrometric analysis routines to be performed, and to average thousands of scans in every experiment, thereby further improving sensitivity. This was fully illustrated by extensive analysis of a 2-fmol peptide mixture, in a 2-microL volume, using a multimode MS approach.