Development of a measles vaccine production process in MRC-5 cells grown on Cytodex1 microcarriers and in a stirred bioreactor

Measles vaccination remains the most efficient way to control the spread of the virus. This work focuses on the production of a measles vaccine using stirred conditions as an advanced option for process scale up. Non-porous Cytodex 1 microcarriers were used to support MRC-5 cell growth in suspension cultures. Virus replication was first optimized in spinner flasks, and the effects of various operational parameters were investigated. Cell infection with AIK-C measles strain at an MOI (multiplicity of infection) of 0.005, without glucose regulation and in M199 medium, resulted in a virus titer of 10^6.25 TCID₅₀ (median tissue culture infective dose)/ml. To optimize the production process in a 7-l bioreactor, we carried out various perfused cultures using minimum essential medium (MEM) + 5% FCS diluted with phosphate-buffered saline (PBS). We achieved a high cell density level (4.1 × 10⁶ cells/ml) with an efficient use of the medium when MEM + 5% FCS diluted with PBS at 25% was used during the cell amplification step. Optimization of measles production in MRC-5 cells grown on Cytodex 1 beads in a 7-l bioreactor showed that perfusion was the most efficient when compared to repeated-batch culture. Perfusion at a rate of 0.25 V (reactor volume)/day showed the highest specific productivity (1.6 IVP [infectious virus particle] cell⁻¹ day⁻¹). Testing of several stabilizers containing pharmaceutically improved components such as sugars, amino acids, and charged ions showed that the formulation composed of sucrose and MgCl₂, led to the maintenance of the infectivity of the AIK-C measles virus strain to a significant level, when stored at +28 °C, +4 °C and −60 °C.     

Kinetic studies on the reaction of ethylenediaminetetraacetatochromium(III) complex with hydrogen peroxide

The rate of reaction of [Cr(III)Y]_aq (Y is EDTA anion) with hydrogen peroxide was studied in aqueous nitrate media [μ = 0.10 M (KNO₃)] at various temperatures. The general rate equation, Rate = $\text{k}{}_1\text{+}\text{k}{}_2\text{K}{}_1\text{[H}{}^{\mathrm{+}}\text{]}{}^{\mathrm{?1}}\text{1 +}\text{K}{}_1\text{[H}{}^{\mathrm{+}}\text{]}{}^{\mathrm{?1}}$ [Cr(III)Y]_aq[H₂O₂] holds over the pH range 5–9. The decomposition reaction of H₂O₂ is believed to proceed via two pathways where both the aquo and hydroxo-quinquedentate EDTA complexes are acting as the catalyst centres. Substitution-controlled mechanisms are suggested and the values of the second-order rate constants k₁ and k₂ were found to be 1.75 × 10^?2 M^?1 s^?1 and 0.174 M^?1 s^?1 at 303 K respectively, where k₂ is the rate constant for the aquo species and k₂ is that for the hydroxo complex. The respective activation enthalpies (ΔH^*₁ = 58.9 and ΔH^*₂ = 66.5 KJ mol^?1) and activation entropies (ΔS^*₁ = ?85 and ΔS^*₂ = ?40 J mol^?1 deg^?1) were calculated from a least-squares fit to the Eyring plot. The ionisation constant pK₁, was inferred from the kinetic data at 303 K to be 7.22. Beyond pH 9, the reaction is markedly retarded and ceases completely at pH ? 11. This inhibition was attributed in part to the continuous loss of the catalyst as a result of the simultaneous oxidation of Cr(III) to Cr(VI).     

A novel animal-component-free medium for rabies virus production in Vero cells grown on Cytodex 1 microcarriers in a stirred bioreactor

Vero cells growth and rabies production in IPT-AF medium, a property animal-component-free medium are described in this work. Kinetics of cell growth and rabies virus (strain LP 2061) production were first conducted in spinner flasks. Over eight independent experiments, Vero cell growth in IPT-AF medium, on 2 g/l Cytodex 1 was consistent. An average Cd (cell division number) of 3.3 ± 0.4 and a specific growth rate μ of 0.017 ± 0.006 h⁻¹ were achieved. Such performances were comparable to those obtained in serum-containing medium (MEM + 10% FCS). Rabies virus production on Vero cells in IPT-AF medium was also optimised in spinner flasks. The effects of multiplicity of infection (MOI), regulation of glucose level at 1 g/l and cell washing step, were investigated. The highest virus titer was achieved when the cells were infected at an MOI of 0.1; this level was equal to 10⁷ FFU/ml. The step of medium exchange before cell infection can be omitted; nevertheless in this case glucose level should be maintained at 1 g/l to avoid a decrease of specific virus productivity. Process optimisation in a 2-l stirred bioreactor pointed out that the aeration mode was the prominent parameter that affected cell growth in IPT-AF medium and on Cytodex 1 microcarriers. An acceptable level of cell density (cell density level of 1.5 × 10⁶ cells/ml) was achieved when cells were grown in batch mode and using headspace aeration. Nevertheless, this aeration mode is not optimal for large-scale culture. The addition of Pluronic F68 at 0.1% at 24 h post inoculation as well as the switch from surface aeration mode to the sparged mode, 2 days after the start of the culture, had markedly improved cell growth performance. A cell density level of 5.5 × 10⁶ cells/ml was reached when cells were grown in a 2-l bioreactor, on 3 g/l Cytodex 1 in IPT-AF medium and using the recirculation culture mode. Cell infection at an MOI of 0.1 and using perfused culture, resulted in a maximal virus titer of 3.5 × 10⁷ FFU/ml. The activity of the pooled inactivated rabies virus harvests showed a protective activity that meets WHO requirements.     

First record of the genus Gynecaptera Skorikov, 1935 (Hymenoptera: Bradynobaenidae: Apterogyninae) from Saudi Arabia,with description of a new species

In the present study, the genus Gynecaptera Skorikov, 1935 Skorikov, A. S. (1935): Zur Mutilliden-Fauna Zentralasiens. Trudy tadzhikskoi basy Akademii Nauk. SSSR, 5, 257–349 + 7 plates. [Google Scholar] is recorded from the Arabian Peninsula for the first time, with a nocturnal new species, G. arabica Soliman &; Gadallah, which has been collected from the Riyadh region in Saudi Arabia and which is described and illustrated.

http://www.zoobank.org/urn:lsid:zoobank.org:pub:F7ACB779-3750-4DC6-B29B-B7F290E7C7B4     

Synthesis and antimycobacterial evaluation of novel 5,6-dimethoxy-1-oxo-2,5-dihydro-1H-2-indenyl-5,4-substituted phenyl methanone analogues

In present investigation, a series of substituted phenyl-5,6-dimethoxy-1-oxo-2,5-dihydro-1H-2-indenylmethanone analogues were synthesized and were evaluated for antimycobacterial activity against Mycobacterium tuberculosis H₃₇Rv and INH resistant M. tuberculosis. All the newly synthesized compounds were showing moderate to high inhibitory activities. The compound 5,6-dimethoxy-1-oxo-2,5-dihydro-1H-2-indenyl-4-fluorophenylmethanone (5g) was found to be the most promising compounds active against M. tuberculosis H₃₇Rv and isoniazid (INH) resistant M. tuberculosis with Minimum inhibitory concentration 0.10 and 0.10 μM.     

The Effect of Shear Rate on the Molecular Mass Distribution of Heat-Induced Aggregates of Mixtures Containing Whey Proteins and κ-Carrageenan

The present study attempts to characterize the effect of shear rate on the composition, size, and molecular weight of the protein aggregates present in the upper layer after phase separation of 5% whey protein isolate (WPI) mixed with 0.5% κ-carrageenan (κ-car) at pH 7.0. The mixtures were heated and sheared under different shearing rates. Size exclusion chromatography (SEC), dynamic light scattering, and static light scattering were employed to describe the effect of shear rate on the size and molecular mass of WPI aggregates. At the molecular level, the size of the aggregates increased with an increase in shear rate. Shear rate also caused a decrease in turbidity of the upper layer after centrifugation. SEC combined with multi-angle laser light scattering showed that the WPI aggregates molecular mass was between 10⁶and 10⁷ g/mol when the shear rate increased from 3.6 to 86.4 s⁻¹. Two empirical models described well the effect of shear rate on the size of WPI aggregates, and both models gave comparable results. By varying process parameters such as flow behavior and temperature, it is possible to control WPI aggregation and, thus, obtain aggregates with a range of different characteristics (size).