Host-induced gene silencing of Pectobacterium carotovorum quorum sensing gene enhances soft rot disease resistance in potato plants

Quorum sensing is a regulatory mechanism of gene expression in bacteria which regulated many physiological processes such as production of virulence factors in Pectobacterium carotovorum. In this research, the plant expression vector, pBI121, harbouring the anti-quorum sensing gene, aiiA, was transformed into Potato (Solanum tuberosum cv. Agria) explants by Agrobacterium mediated transformation procedure and putative transformants containing pBI121/aiiA were obtained. The results of bioassay test revealed that the expression of aiiA gene in potato plant induces the resistance to the early stage of bacterium pathogenesis. The soft rot symptoms such as wilting, yellowing and tissue maceration were not observed until 48?hr after inoculation of transgenic potatoes with P. carotovorum. Although in non-transgenic plants, the disease symptoms were appeared after 24?hr of plants infection. Hence, this study proves that the heterologous expression of aiiA gene enhances the resistance against potato soft rot disease.     

Demonstration of the intracellular accumulation of intermediary fluorescent metabolites of various polycyclic aromatic hydrocarbons by resolution of the fluorescence spectra of isolated living cells

Using microspectrofluorimetry, we have studied some spectral modifications induced by the accumulation of fluorescent metabolites from some PAH in single living cells (3T3 and RTG2 fibroblasts). Whatever the parent compound under study, no spectral deformation has been detected in the 3T3 cells. On the contrary, the characteristic fluorescence spectra were strongly modified in RTG2 cells when the parent compound was either B(a)P or CPAP. The B(a)P metabolites have been identified as 3-OH-B(a)P and 9-OH-B(a)P.     

Evaluating the effect of a mixture of two main conjugated linoleic acid isomers on hepatic steatosis in HepG2 cellular model

Molecular Biology Reports - Hepatic steatosis is an early form of non-alcoholic fatty liver disease (NAFLD), caused by abnormal fat deposition in the hepatocytes. Conjugated linoleic acid (CLA) is...     

Improved osteogenic differentiation of human induced pluripotent stem cells cultured on polyvinylidene fluoride/collagen/platelet-rich plasma composite nanofibers

Blood transfusion or blood products, such as plasma, have a long history in improving health, but today, platelet-rich plasma (PRP) is used in various medical areas such as surgery, orthopedics, and rheumatology in many ways. Considering the high efficiency of tissue engineering in repairing bone defects, in this study, we investigated the combined effect of nanofibrous scaffolds in combination with PRP on the osteogenic differentiation potential of human induced pluripotent stem cells (iPSCs). Electrospinning was used for fabricating nanofibrous scaffolds by polyvinylidene fluoride/collagen (PVDF/col) with and without PRP. After scaffold characterization, the osteoinductivity of the fabricated scaffolds was studied by culturing human iPSCs under osteogenic medium. The results showed that PRP has a considerable positive effect on the biocompatibility of the PVDF/col nanofibrous scaffold when examined by protein adsorption, cell attachment, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays. In addition, the results obtained from alkaline phosphatase activity and calcium content assays demonstrated that nanofibers have higher osteoinductivity while grown on PRP-incorporated PVDF/col nanofibers. These results were also confirmed while the osteogenic differentiation of the iPSCs was more investigated by evaluating the most important bone-related genes expression level. According to the results, it can be concluded that PVDF/col/PRP has much more osteoinductivity while compared with the PVDF/col, and it can be introduced as a promising bone bio-implant for use in bone tissue engineering applications.     

An improved cage system for the bioassay of Metarhizium anisopliae on Thrips tabaci (Thysanoptera: Thripidae)

The ability of thrips and other minute insects to escape from conventional assay cups led to development of a successful assay chamber. In the present study, we evaluated three bioassay systems for thrips; Tashiro cage, microtube assay and leaf sandwich assay and introduced an improved thrips entomopathogenic bioassay system (TEBS). Our objective was to investigate the effect of Metarhizium anisopliae on Thrips tabaci using an easy-to-use and inexpensive holding chamber that would produce bioassay results with acceptable levels of accuracy and precision. In our assays, we found that escape of second-instar larvae from TEBS was significantly less than those of other methods which we tested. Our results indicated that our assay system was more suitable than the other conventional assays for the bioassay of entomopathogenic fungi on T. tabaci.     

Genetic diversity and population structure in four Cirsium (Asteraceae) species

The present study considers genetic diversity of 38 populations in 4 Cirsium species of the genus Cirsium Mill. (Asteraceae), occurring in different ecological regions and tries to compare degree of genetic variability among the species with wide geographical distribution versus endemic C. pyramidale showing confined geographical distribution. The results showed that the endemic species has similar value of genetic diversity parameters as the species with wider distribution. We also studied the possible admixture nature of these populations and tried to understand the relation between genetic changes, geographical distribution and polyploidy level and chromosome pairing in these species. ISSR analysis showed population difference in allele composition and frequency. Clustering and PcoA ordination produced different groupings in each species, while STRUCTURE and reticulation analyses revealed high degree of genetic admixture and gene exchange among populations as well as allelic rearrangement. No significant correlation was observed between geographical distance and genetic distance of the populations and AMOVA test revealed no significant difference among populations in each species studied. However, high amount of within population variation occurred in all 4 species indicating their cross-pollination nature and high genetic admixture. The populations also varied in chiasma frequency and chromosome pairing as well as the occurrence of heterozygote translocations all creating more variability to be used by plants for local adaptation.     

Effect of Fine-Grain Percent on Soil Strength Properties Improved By Biological Method

In many civil engineering projects, the foundation soils do not provide the required mechanical properties and therefore, there is a need to improve the soil. Compaction, soil reinforcement, soil mixing with natural, or chemical additives are common soil stabilization methods used to improve the soil mechanical properties. The incidence of some environmental problems in traditional improvement techniques has encouraged engineers to explore new methods. Recently in this category, a new technique in geotechnical engineering called biogeotechnology is introduced to improve the mechanical properties of the soil. It is an environmentally friendly approach that uses biological methods to solve geotechnical problems. This technique uses minerals producer microorganisms. This study investigates the possibility of improving soil strength properties with microbial calcite precipitation and the effect of fine-grained percentages in this regard. In order to determine the soil strength properties, consolidated drained direct shear tests have been carried on untreated and treated soil samples. The results showed that this method is applicable to improve all soil samples (from 100% coarse-grained (i.e., sand) to 100% fine-grained (i.e., clay)). However, increasing the strength in the sand is much more enhanced than that for finer soils. It was found that a considerable increase in cohesion of treated soil can be achieved for soil samples with maximum 10% fine content.