Modulation of the immune response by Middle East respiratory syndrome coronavirus

Coronavirus (CoV) infections are commonly associated with respiratory and enteric disease in humans and animals. In 2012, a new human disease called Middle East respiratory syndrome (MERS) emerged in the Middle East. MERS was caused by a virus that was originally called human coronavirus-Erasmus Medical Center/2012 but was later renamed as Middle East respiratory syndrome coronavirus (MERS-CoV). MERS-CoV causes high fever, cough, acute respiratory tract infection, and multiorgan dysfunction that may eventually lead to the death of the infected individuals. The exact origin of MERS-CoV remains unknown, but the transmission pattern and evidence from virological studies suggest that dromedary camels are the major reservoir host, from which human infections may sporadically occur through the zoonotic transmission. Human to human transmission also occurs in healthcare facilities and communities. Recent studies on Middle Eastern respiratory continue to highlight the need for further understanding the virus-host interactions that govern disease severity and infection outcome. In this review, we have highlighted the major mechanisms of immune evasion strategies of MERS-CoV. We have demonstrated that M, 4a, 4b proteins and Plppro of MERS-CoV inhibit the type I interferon (IFN) and nuclear factor-κB signaling pathways and therefore facilitate innate immune evasion. In addition, nonstructural protein 4a (NSP4a), NSP4b, and NSP15 inhibit double-stranded RNA sensors. Therefore, the mentioned proteins limit early induction of IFN and cause rapid apoptosis of macrophages. MERS-CoV strongly inhibits the activation of T cells with downregulation of antigen presentation. In addition, uncontrolled secretion of interferon ɣ-induced protein 10 and monocyte chemoattractant protein-1 can suppress proliferation of human myeloid progenitor cells.     

Isolation and detection of Leishmania species among naturally infected Rhombomis opimus, a reservoir host of zoonotic cutaneous leishmaniasis in Turkemen Sahara, North East of Iran

In Iran, three species of Leishmania have been incriminated as the causative agents of human leishmaniasis, Leishmania (L.) major, Leishmania tropica, and Leishmania infantum.Rhombomis opimus have been incriminated as a principal reservoirs of the parasitic protozoan Leishmania major, the causative agent of rural zoonotic cutaneous leishmaniasis (ZCL) in Iran. Rodents captured and examined to find Leishmania species using conventional methods including direct impression smear and microscopic observation inoculation samples to Balb/c and culture in NNN medium. Also molecular method was employed to detect Leishmania in rodents by amplifying a region of the ribosomal RNA amplicon of Leishmania (ITS1-5.8S rRNA–ITS2) using Nested PCR. Leshmania species were specified by DNA sequences. 36 (38.3%) of R. opimus were Leishmania positive using at least one conventional methods. Many more ITS-rDNA fragments were amplified from R. opimus but only 65 out of 74 PCR products contained enough DNA for direct sequencing or readable sequences. The PCR assays detected in Iranian R. opimus not only Leishmania major in 59 (79.7%) rodents but also Leishmania turanica in 6 (8.1%) rodents, another parasite of the great gerbil. These parasites were found in Turkemen Sahara, North East of Iran, in a focus of rural (ZCL). L. major and L. turanica in R. opimus firmly identified from Turkemen Sahara. Nine rodents with Leishmania infections unidentified which some were unreadable sequences, these could be mixed infections of L. major, L. turanica, Leishmania gerbillisensu lato and Leishmania close to L. gerbilli or a related species reported in sandflies previously from this location. The haplotypes of L. major and L. turanica were found to be identical to that of isolates of L. major and L. turanica from Iran and in GenBank elsewhere. R. opimus is probably the key reservoir in this ZCL focus because of its abundance and its infection rates with both L. major and L. turanica.     

Mycoflora of Iranian Maize Harvested in the Main Production Areas in 2000

Maize is one of the most important cereals produced in, and imported into, Iran. The incidences of seed-borne fungi were determined in Iranian maize harvested in 2000 from four major production areas with different climatic conditions, namely Fars, Khuzestan, Kermanshah and Mazandaran provinces. This is the first study to compare the mycoflora of maize in the aforementioned areas. Mycological analyses showed a predominance of Fusarium species (38.5%), followed by Aspergillus species (8.7%), Rhizopus species (4.8%), Penicillium species (4.5%), Mucor species (1.1%), and four other fungal genera. Fusarium verticillioides was the most prevalent species (83% of Fusarium isolates and 52% of the total isolations), with the highest incidence in Mazandaran (59%), a region of Iran with the highest rainfall and relative humidity, high rate of esophageal cancer (EC) and high levels of fumonisins in maize. Aspergillus flavus was the most widely recovered Aspergillus species and 38% of samples were contaminated with this potentially aflatoxigenic fungus. The incidence of A. flavus was highest in Kermanshah, the province with lowest mean minimum temperature. Penicillium species were seen in all the samples and Fars had the highest incidence, with highly significant differences when compared to the other three provinces. Diplodia species were not isolated from any of the samples examined.     

Investigation of chromatography and polymer/salt aqueous two-phase processes for downstream processing development of recombinant phenylalanine dehydrogenase

This work presents a comprehensive study between the polymer/salt aqueous two-phase systems (ATPS) and chromatography process for downstream processing of recombinant Bacillus badius phenylalanine dehydrogenase (PheDH). First, the partitioning behavior of recombinant PheDH in polyethylene glycol (PEG)/K₂HPO₄ ATPS was examined. For comparative purpose, a classical chromatographic protocol was performed as well. Investigation of chromatography and ATPS procedures revealed that the ATPS comprising of 9% (w/w) PEG-6000, 16% (w/w) K₂HPO₄ and 16% (w/w) KCl with pH of 8.0, volume ratio (V _R ) of 0.25, temperature of 25 °C and 40% (w/w) cell lysate ensured the most favorable approach for PheDH downstream process. A specific activity of 4,231.4 U/mg, a yield of 96.7% and a recovery of 162.0% were obtained. Furthermore, the shorter process time (4 vs. 48 h) and the lower total cost (4 vs. 20 €) were additionally features that confirmed the suitability of proposed technique.     

Cloning and expression of Bacillus sphaericus phenylalanine dehydrogenase gene in Bacillus subtilis cells: purification and enzyme properties

Cloning and expression of the L-phenylalanine dehydrogenase (PheDH) gene from Bacillus sphaericus in B. subtilis was performed. It was ligated into the pHY300PLK shuttle vector and the resulting plasmid, pHYDH encoding polypeptide with molecular weight of 340 kDa, then transformed in B. subtilis ISW1214 and Escherichia coli JM109 competent cells for expression. Bacillus subtilis ISW1214/pHYDH only produced PheDH enzyme (4700 U/l). The recombinant PheDH was purified to near homogeneity as judged by SDS–polyacrylamide gel electrophoresis (M _r 41000 Da) and the result was 40-fold with a yield of about 54%. Apparent K _m values for L-phenylalanine (Phe), L-tyrosine and NAD⁺ were 0.24, 0.48 and 0.19 mM respectively. The optimum pH of the recombinant enzyme was 11 for the oxidative deamination, 10.2 for the reductive amination. The features of recombinant PheDH enzyme were comparable with the wild type PheDH protein.