Models of dependence of the quantity of the Streptococcus pneumoniae biomass and his capsular polysaccharide from the composition of the feeding environment

Aim.The development of a semi-synthetic nutrient medium that provides the maximum amount of capsular polysaccharide (CPS). Materials and methods. We used the strain 521 of S. pneumoniae serotype 23F. Cultivation was carried out in test tubes with 10 ml of polysynthetic nutrient medium of a specific composition. The amount of polysaccharide in the samples was determined using rocket immunoelectrophoresis. Building models and comparing the effects of various components was carried out according to the methodology specified in the tutorial. The calculation of the coefficients of the equation and the assessment of the adequacy of the equations themselves was carried out using RStudio version 1.0.153. Results. As a result of a series of experiments, the coefficients of the regression equations were calculated, their significance was evaluated, and models of dependence of biomass production and CPS were constructed depending on the composition of the nutrient medium. To solve the problem, an experiment was carried out according to the Box-Wilson method. The peptone and glucose concentrations were selected as optimized parameters. The step size ΔSi in the increasing gradient direction was calculated based on the coefficients of the regression equation. At the same time, the exact nature of the dependence was determined. The optimal calculated concentrations of peptone and glucose, at which the formation of CPS is maximum, are 32.6 and 12.1 g/l, respectively. In this case, the forecast yield of the polysaccharide is 239 mg/l. Conclusion. Using the method of fractional factorial experiment, models of the dependence of the biomass amount of S. pneumoniae and its capsular polysaccharide on the composition of the nutrient medium were obtained. The optimal concentrations of the components of the medium were found, which make it possible to increase the level of biomass formation by 10% compared to the standard formulas, and the CPS — by 1.5—2 times.

A METHOD FOR THE PREPARATION OF LUBRICATING OIL FROM MICROALGAE BIOMASS

The paper presents a method for the preparation of lubricating oil from the biomass of single-cell green algae Chlorella sp. The microalgae were grown in a synthetic nutrient medium under laboratory conditions. The biomass, which was obtained from the culture, was subjected to the process of dehydration, freeze-drying, and solvent extraction, in order to separate lipids that may be a feedstock for eco-friendly lubricants. The chemical structure of obtained bioproducts (biomass and algal oil) was investigated by means of Fourier Transform Infrared Spectrophotometry. Moreover, rheological characteristics (kinematic viscosity at 40 and 100°C, dynamic viscosity at 0–100oC) of the algal oil were determined. The results of the laboratory tests show that the oil has the chemical structure and viscosity-temperature properties similar to the rapeseed oil. This creates a potential opportunity to replace used vegetable lubricants or additives by algal oil in many technical areas.

Structural features of the vesicle of Frankia sp. CpI1 in culture

The filamentous bacterium Frankia sp. CpI1 of the Actinomycetales, responsible for symbiotic nitrogen fixation in the nodules of certain woody dicots, also fixes dinitrogen when grown independently of the host in a nitrogen-free synthetic nutrient medium under aerobic conditions. In structural studies of Frankia grown in culture it has been shown that the bacterial filaments form vesicles, enlarged terminal endings in which the enzyme nitrogenase is formed. Microscopic examination of cultures shows that the vesicles possess a specialized envelope consisting of a number of thin layers or laminae which in polarized light show birefringence and in freeze-etch electron microscopy are resolved as multiple (12–15) laminae approximately 35–40 Å (1 Å = 0.1 nm) in thickness. Comparisons are made between the structure of the vesicle envelope in cultured Frankia and the strikingly similar innermost laminated layer in the dinitrogen-fixing heterocysts of the cyanobacterium Anabaena. Comparable protective functions in limiting oxygen to the dinitrogen-fixing sites are suggested for these similar structures in two quite unrelated microorganisms.

CULTIVATION OF POLIOMYELITIS VIRUS IN TISSUE CULTURE IV. FURTHER OBSERVATIONS ON VIRUS PROPAGATION IN HUMAN TISSUES WITH A SYNTHETIC NUTRIENT MEDIUM

This paper presents further observations on the propagation of the Lansing strain of poliomyelitis virus in Maitland-type cultures of human tissue derived from embryonic brain and cord and from kidney, in a synthetic nutrient medium. The survival time of cultures of human embryonic brain and cord was previously found to be over 70 days, and we now report that cultures of human embryonic kidney have survived for over 100 days. Virus has been detected in the supernatant fluids of cultures of brain and cord for more than 60 days, and of kidney for more than 100 days. Virus titers of more than 10−3.0 have been obtained in cultures of human embryonic kidney. Human tonsillar tissue has survived for more than 50 days in cultures, and virus has been detected in the supernatant fluids for more than 40 days. Studies on glucose utilization have been of value in estimating the level of metabolism of these tissues.

CULTIVATION OF POLIOMYELITIS VIRUS IN TISSUE CULTURE V. OBSERVATIONS ON VIRUS PROPAGATION IN CERTAIN ANIMAL TISSUES WITH A SYNTHETIC NUTRIENT MEDIUM

Further observations have been made on the propagation of Lansing poliomyelitis virus in tissue cultures. It has been observed that tissues derived from several organs of rhesus monkeys will support virus growth in tissue cultures in Erlenmeyer flasks with a synthetic medium as the source of nutrient. Cultures of tissues from monkey testis, lung, kidney, and gut have survived for long periods, and virus has been regularly recovered even from fluids removed from cultures after as late as 125 days. Cultures of tissues from monkey brain and cord, and muscle, did not survive as long, and less virus was demonstrated in the supernatant fluids. Muscle from the diaphragm did not appear to support growth. Cultures of tissues from the brain, kidney, and lung of beef embryos survived for long periods, but no virus was found in any of the culture fluids.