فصلنامه ایمنی زیستی
سال یازدهم شماره 4 (زمستان 1397)

Today's most of microorganisms are used for purification of hazard waste such as municipal and industrial waste water and oil contaminants. In this study 2 bacterial species were isolated and purified in hydrocarbon (anthracene) containing media from oil polluted sediment of Imam Khomeini port. Bacillus pasteurii and Amphibacillus xylanus species were identified as indicator degrading bacteria in media containing 30 ppm anthracene. Results showed among these bacteria, Bacillus pasteurii had faster growth and compatibility on solid medium containing anthracene oil hydrocarbon for 5 days at 30̊ C incubation.

Serious attention to hazardous chemical pesticides began with publication of the book “Silent Spring” by Rachel Carson in 1962. Scientists believe that agriculture had the greatest impact on the environment. The most reliable evidence comes from application of million tons of chemical fertilizers and pesticides with short or long adverse effects on ecosystem. Therefore, it is essential to implement effective strategies such as biological materials to reduce chemical pollutants. Unfortunately, there is very little information about the practical use of these valuable resources. This article compares chemical and biological herbicides in brief and may be useful for introducing young scientists with non-chemical weed control methods and encourage them to research the issue.

Approximately 5.6 billion pounds of pesticides are consumed annually around the world. The important environmental impact in this regard is that the pesticides are continuously displaced from one environment to another, and leave negative effects in each environment. Studies have shown that more than 98% of insecticides and 95% of sprayed herbicides reach other targets (other than their main purpose), including non-target species, air, water, soil and food. Various physical, chemical and biological methods have been developed to reduce the environmental impacts of pesticides, in which microbiological remediation is one of the least harmful methods for the elimination of contaminants. Considering the effect of plant growth promoting rhizobacteria (PGPR) on improving plant growth, the use of these bacteria for bioremediation of pesticide can increase their competitive ability of bio-based product in the market. In this paper, it has been attempted in the first step to address some of the destructive aspects of organic phosphorus pesticides as one of the most important pesticides. Further, an effective solution to refining these types of insecticides is mentioned.

Plants continuously confronted with unfavorable environmental conditions such as heavy metal stress Cadmium (Cd) is currently one of the most important environmental pollutants. Among heavy metals, cadmium (Cd) is a non-essential and toxic metal rapidly taken up by roots and accumulated in various plant tissues which hamper the crop growth and productivity worldwide. The main symptoms of Cd toxicity to plants are stunting and chlorosis. Plants employ various strategies to counteract the inhibitory effect of Cd, which include cell wall binding, chelation with phytochelatins (PCs), compartmentation of Cd in vacuole and enrichment in leaf trichomes. In spite of its high phytotoxicity, Cd is easily taken up by plant roots and transported to above-ground tissues and enters into the food chain where it may pose serious threats to human health.This review has focused on recent evidevce that identifies potential mechanism that may be involved in the tolerance plant to heavy metal in envierment.

In order to understand the ecology of viruses, it is necessary to obtain comprehensive information on virus-virus and virus-host interactions in natural systems. In this study, it is found that RNA-Seq enabled this analysis without prior assumptions about infectious viruses, virus symptoms, or host genes. New generation sequencing allows identifying potential facilitators of multiple infections. Host antiviral responses occur naturally under RNA silencing. Because research into plant viruses has focused primarily on crop diseases, little is known about these viruses in the wild. RNA sequencing in plants belonging to a natural population is used to determine the simultaneous presence or absence of all viruses whose sequence has been reported, to identify new viruses, and to quantify host transcriptomes. By introducing the criteria for the number of readings and coverage of the genome, virus-induced infections and intrinsic and latent plant-virus interactions can have important applications in controlling these pathogens.

Abiotic stresses in numerous forms are the significant reason behind large-scale yield loss of agriculturally vital crops such as rice for a long time. Different approaches apply to combat adverse environmental conditions from traditional techniques to novel molecular biology strategies or genetic engineering in plants. The microRNAs (miRNAs) are a group of the small, intriguing molecule of approximately 22 nucleotides that play significant roles not only in the regulation of gene expression but also additionally take part in transcriptional regulation and nutrient homeostasis within the plant system. Most importantly, it is estimated that the miRNAs are significantly involved in the mitigation of multiple plant abiotic stresses, thus a comprehensive understanding of miRNA-mediated abiotic stress mitigation may serve to develop suitable alternative strategies for abiotic stress alleviation in rice plants. Our study specifically deals with the role of different plant miRNAs in drought stress, heat stress, cold stress, salinity stress, and nutrient stress. Furthermore, this review is focusing on the potential mechanism by which miRNAs work in different abiotic stresses by regulating different gene expression. Finally, we additionally suggest some of the possible miRNA targets that may be addressed in the near future, for the genetic improvement of important crops such as rice.