Epidemiological evidence of mosquito-borne viruses among persons and vectors in Iran: A study from North to South

Arthropod-borne viruses are a group of the most important emerging pathogens. They cause a range of diseases in vertebrate hosts and threaten human health (Gan and Leo, 2014). The global distribution of arboviruses is associated with the vector which is strongly affected by changes in environmental conditions. Dengue virus (DENV) and Chikungunya virus (CHIKV), which cause high annual infected cases and have an increasing geographic distribution, are transmitted by Aedes spp. mosquitoes, in particular Ae. albopictus and Ae. Aegypti (Presti et al., 2014; Higuera and Ramírez, 2018). Although, the main vector of dengue virus, Ae. aegypti, was not detected in Iran, other possible important vectors such as Ae. Albopictus and Ae. unilineatus were recorded (Doosti et al., 2016; Yaghoobi-Ershadi et al., 2017). West Nile virus (WNV), a member of the genus Flaviviruses, is one of the most widespread arboviruses (Chancey et al., 2015). The epidemiological evidence of WNV in different hosts in Iran was found (Bagheri et al., 2015), and the circulation of WNV in the main vector, Culex pipiens s.l. and Cx. pipiens, has been proved (Shahhosseini et al., 2017). Due to limited information on the situation of CHIKV, DENV and WNV in Iran, we performed a wide geographical investigation to determine the prevalence of IgG specific antibodies in human samples as well as the genome of WNV, CHIKV and DENV in mosquitoes.     

High throughput automated microbial bioreactor system used for clone selection and rapid scale‐down process optimization

High throughput automated fermentation systems have become a useful tool in early bioprocess development. In this study, we investigated a 24 x 15 mL single use microbioreactor system, ambr 15f, designed for microbial culture. We compared the fed‐batch growth and production capabilities of this system for two Escherichia coli strains, BL21 (DE3) and MC4100, and two industrially relevant molecules, hGH and scFv. In addition, different carbon sources were tested using bolus, linear or exponential feeding strategies, showing the capacity of the ambr 15f system to handle automated feeding. We used power per unit volume (P/V) as a scale criterion to compare the ambr 15f with 1 L stirred bioreactors which were previously scaled‐up to 20 L with a different biological system, thus showing a potential 1,300 fold scale comparability in terms of both growth and product yield. By exposing the cells grown in the ambr 15f system to a level of shear expected in an industrial centrifuge, we determined that the cells are as robust as those from a bench scale bioreactor. These results provide evidence that the ambr 15f system is an efficient high throughput microbial system that can be used for strain and molecule selection as well as rapid scale‐up. © 2017 The Authors Biotechnology Progress published by Wiley Periodicals, Inc. on behalf of American Institute of Chemical Engineers Biotechnol. Prog., 34:58–68, 2018     

A cell engineering strategy to enhance supercoiled plasmid DNA production for gene therapy

With the recent revival of the promise of plasmid DNA vectors in gene therapy, a novel synthetic biology approach was used to enhance the quantity, (yield), and quality of the plasmid DNA. Quality was measured by percentage supercoiling and supercoiling density, as well as improving segregational stability in fermentation. We examined the hypothesis that adding a Strong Gyrase binding Site (SGS) would increase DNA gyrase‐mediated plasmid supercoiling. SGS from three different replicons, (the Mu bacteriophage and two plasmids, pSC101 and pBR322) were inserted into the plasmid, pUC57. Different sizes of these variants were transformed into E. coli DH5α, and their supercoiling properties and segregational stability measured. A 36% increase in supercoiling density was found in pUC57‐SGS, but only when SGS was derived from the Mu phage and was the larger sized version of this fragment. These results were also confirmed at fermentation scale. Total percentage supercoiled monomer was maintained to 85–90%. A twofold increase in plasmid yield was also observed for pUC57‐SGS in comparison to pUC57. pUC57‐SGS displayed greater segregational stability than pUC57‐cer and pUC57, demonstrating a further potential advantage of the SGS site. These findings should augment the potential of plasmid DNA vectors in plasmid DNA manufacture. Biotechnol. Bioeng. 2016;113: 2064–2071. © 2016 The Authors. Biotechnology and Bioengineering Published by Wiley Periodicals, Inc.     

Current status of the management of fall webworm,Hyphantria cunea: Towards the integrated pest management development

The fall‐webworm (FWW), Hyphantria cunea, is a highly polyphagous insect pest that is native to North America and distributed in different countries around the world. To manage this insect pest, various control methods have been independently evaluated in the invaded areas. Some of the control methods have been limited to the laboratory and need further study to verify their effectiveness in the field. On the other hand, currently, integrated pest management (IPM) has become a promising ecofriendly insect pest management option to reduce the adverse effect of insecticides on the environment. The development of an IPM for an insect pest must combine different management options in a compatible and applicable manner. In the native areas of the insect pests, there are some recommended management options. However, to date, there is no IPM for the management of the FWW in the newly invaded areas. Therefore, to develop an IPM for this insect pest, compilation of effective management option information is the first step. Thus, believing in the contribution of an IPM to the established management strategies, the chemical, biological, natural enemy, sex pheromone, and molecular studies regarding this insect were reviewed and potential future research areas were delineated in this review study. Therefore, using the currently existing management options, IPM development for this insect pest should be the subject of future research in the newly invaded areas.     

Genetic diversity in merozoite surface protein (MSP)-1 and MSP-2 genes of Plasmodium falciparum in a major endemic region of Iran

Merozoite surface protein-1 (MSP-1) and merozoite surface protein-2 (MSP-2) were used to develop vaccines and to investigate the genetic diversity in Plasmodium falciparum malaria in Iran. Nested polymerase chain reaction amplification was used to determine polymorphisms of block 2 of the MSP-1 and the central domain of MSP-2 genes. A total of 67 microscopically positive P. falciparum infected individuals from a major endemic region, southeast Iran, were included in this trial. Nine alleles of MSP-1 and 11 alleles of MSP-2 were identified. The results showed that amplified product from these surface antigen genes varied in size and there was specific pattern for each isolate. Besides, regarding this pattern, 23 multiple infections with at least 2 alleles were observed. While the endemic regions of malaria in Iran is classified in low to moderate group, but extensive polymorphism was observed for each marker and the MSP-2 central repeat was the most diverse that could be considered in designing malaria vaccine.     

Step change in the efficiency of centrifugation through cell engineering: co‐expression of Staphylococcal nuclease to reduce the viscosity of the bioprocess feedstock

Cell engineering to enable step change improvements in bioprocessing can be directed at targets other than increasing product titer. The physical properties of the process suspension such as viscosity, for example, have a major impact on various downstream processing unit operations. The release of chromosomal DNA during homogenization of Escherichia coli and its influence on viscosity is well‐recognized. In this current article we demonstrate co‐expression of Staphylococcus aureus nuclease in E. coli to reduce viscosity through auto‐hydrolysis of nucleic acids. Viscosity reduction of up to 75% was achieved while the particle size distribution of cell debris was maintained approximately constant (d₅₀ = 0.5–0.6 µm). Critically, resultant step change improvements to the clarification performance under disc‐stack centrifugation conditions are shown. The cell‐engineered nuclease matched or exceeded the viscosity reduction performance seen with the addition of exogenous nuclease removing the expense and validation issues associated with such additions to a bioprocess. The resultant material dramatically altered performance in scale‐down mimics of continuous disc‐stack centrifugation. Laboratory scale data indicated that a fourfold reduction in the settling area of a disc‐stack centrifuge can be expected due to a less viscous process stream achieved through nuclease co‐expression with a recombinant protein. Biotechnol. Bioeng. 2009; 104: 134–142 © 2009 Wiley Periodicals, Inc.     

Spontaneous activity of dopaminergic retinal neurons

Dopaminergic local circuit neurons in the retina (DA cells) show robust, spontaneous, tetrodotoxin-sensitive pacemaking. To investigate the mechanism underlying this behavior, we characterized the sodium current and a subset of the potassium currents in the cells in voltage-clamp experiments. We found that there is a persistent component of the sodium current in DA cells which activates at more depolarized potentials than the transient component of the current. The transient component was completely inactivated at -50 mV, but DA cells remained able to fire spontaneous action potentials when potassium channels were partially blocked and the membrane potential remained above -40 mV. Based on these electrophysiological data, we developed a reduced computer model that reproduced the major features of DA cells. In simulations at the physiological resting potential, the persistent component of the sodium current was both necessary and sufficient to account for spontaneous activity, and the major contribution of the transient component of the sodium current was to initiate the depolarization of the model cell during the interspike interval. When tonic inhibition was simulated by lowering the input impedance of the model cell, the transient component played a larger role.     

The influence of small oligosaccharides on the immune system

In this study, oligosaccharides known to enhance the synthesis of penicillin by Penicillium chrysogenum have been presented to human immune cells and their effect measured. In addition a range of commercially available oligosaccharides have been tested. Results obtained indicate that oligosaccharides with a degree of polymerisation greater than 6 and with a tendency to form helical structures are most effective at influencing the immune system as measured by the production of reactive oxidising species. Laminariheptaose has been shown to increase reactive oxidising species production by up to 25%, whilst mannan-oligosaccharides with a DP of 6 to 7 decrease production by up to 44%. These and other results show that the immune system can recognise subtle differences in oligosaccharides and that these oligosaccharides could potentially be used to modulate the immune response.     

Elicitor effects on reactive oxygen species in liquid cultures of Penicillium chrysogenum

Activity of reactive oxygen species (ROS) was investigated in liquid cultures of Penicillium chrysogenum P2 supplemented with carbohydrates. Oligosaccharides lowered the ROS activity in all samples. The greatest effect occurred when oligosaccharides were added to samples 48 h after inoculation. The ROS decrease in the presence of oligoguluronate, oligomannuronate and mannan oligosaccharides was 18%, 36% and 54%, respectively (ROS levels varied notably with culture age and type of elicitor). The polysaccharides from which the oligosaccharides were derived showed little (5-10%) overall decrease of ROS.