فصلنامه ایمنی زیستی
سال نهم شماره 4 (زمستان 1395)

Biodiversity ensures the existence of every ecosystem. Among the levels of biodiversity, genetic diversity, as raw material for breeding, has gained more attention in agricultural societies, scope of which is considered as a durability index of productivity. Genetic resources constitute the foundation of modern agriculture and are necessary for attaining food security. The hazard of loss of genetic resources first came into the attention of scientists in middle of twentieth century, followed by universal implements to protect these valuable reservoirs. However, breeding methods per se restrict genetic base and cause genetic vulnerability against unfavorable environmental conditions and biotic stresses. On the other hand, high potential existing in genetic resources, as repository of precious characteristics, has remained unutilized. The advent of genetic engineering modified many concepts in various domains including genetic resources. Having the capacity to pass the limiting borders, this technology is promising to make concealed potential of genetic resources free and enhance germplasm. Genetic engineering targets and harnesses harmful pests, conserving the useful organisms. This technology has prevented the soil erosion through encouraging the farmers to adopt conservation agriculture methods in different countries leading to biodiversity conservation of the soil. Having in mind the valuable attainments of genetic engineering in food production and security and great revolution expected by this technology in future, it may be stated that human being has entered a new era of supplying his basic necessities.

Plants are considered as one of the world’s valuable genetic resources. It is expected that more than 15 to 40 percent of all living species will become extinct by the year 2050. Since 1960, studies were seriously raised over species going extinct as well as conservation of genetic resources leading to establishment of international organizations. These organizations have proposed some actions to protect endangered species such as, establishing of plant gene banks, determining protected areas for the conservation of genetic resources, and cultivation of becoming extinct plant species in the botanical gardens. Their works was mainly based on new procedures such as genetic engineering as a quick and efficient tool to save becoming extinct species. This technique allows identification and cloning genes responsible for resistance against biotic and abiotic stresses from different organisms and transferring the resistance resources into becoming extinct species to save them. The aim of this study was to investigate the role of transgenic plants in the conservation of becoming extinct species and increase of biodiversity.

Nanotechnology and genetic engineering with broad applications in medicine, agriculture and industry fields are the most efficient technologies that are used to meet human being needs and reduce their environmental impacts. However, these technologies and their productions lead to make several concerns about environmental, human health, economics, social, cultural and ethical issues in all countries. Furthermore, these technologies, like other new technologies, can provide several efficient benefits as well as their several potential risks, which are seemed to be making them almost unsafe. Nevertheless, using the basic researches and sufficient and informative awareness of human societies associated with benefits and concerns of genetically modified organisms (GMOs) leads to make some social familiarities with benefits of genetic engineering in agriculture and change the social approaches. On the other hand, several GMO concerns can be solved by scientific logics and people who consumers GMO products can enjoy the benefits. In contrast, nanotechnology products, which are seemed to be secure and safe, should be contained with biological and environmental controls to reduce their collateral negative effects. However, to obtain more information about these effects, the comprehensive researches are needed.

Genetically modified crops are those whose genetic makeup have been altered; thus, possess a novel combination of genetic material obtained through the use of modern biotechnology. In Iran, the current debate on the production of genetically modified crops, developed by the national scientist, demonstrates the serious conflict between two groups: 1) Agri-biotech scientists who consider agricultural biotechnology as a solution to food shortage, the scarcity of environmental resources and weeds and pests invasion; and 2) non- specialized scientists and environmentalists who warn that genetically modified crops introduces new risks to the environment and human health such as loss of biodiversity, food allergies, cancer, productivity loss and other unintended effects.  In this review, the scientific literature on the effects of feeding GE crops on performance and health of animals and composition of products derived from them are summarized. Moreover, the field experience of feeding the commercial livestock populations with GE feed sources is also discussed.

In this study, chemical compounds of Melia azedarach L. fruit and the insecticidal effect of extract & powders was investigated on adult insects of Tribolium castaneum Herbst (Col. Tenebrionidae). Bioassays experiment with contact method was performed in a completely randomized design in laboratory conditions (temperature 25± 5 °C and relative humidity 65 ± 5%). Mortality percentage of T. castaneum by Melia fruit extract calculated at three concentrations (10, 50 and 80 mg/ml) after 12, 24 & 36 hours and also by Melia fruit powder at four different dosage (3, 4, 5 and 6 gr) after 24, 48, 72 & 96 hours respectively. Significant differences were observed on mortality percentage of T. castaneum by Melia fruit extract and powder on different concentrations after each of the times. Based on the results, mortality increased with the passage of time. The lowest and highest mortality of T. castaneum was in use of M. azedarach fruit extract in 10 and 80 mg/ml concentrations after 12 & 36 hours (17.50± 2.50 % & 81.75 ± 11.89%) respectively. Also the highest and lowest mortality rate of adult insects was obtained when used Melia fruit powder at a dose of 3 and 6 grams after 24 & 96 hours (3.33 ± 2.36% & 92.00± 5.89%) respectively. In this study, 52 chemical compounds of the Melia fruit were identified by GC/Mass. The major material contains: Ethane, 1,1-diethoxy-; Methanecarbothiolic acid; Ethyl Acetate; α-D-Glucopyranoside, O-α-D-glucopyranosyl-(1.fwdarw.3)-β-D-fructofuranosyl; N,N,O-Triacetylhydroxylamine and 2,4-Dihydroxy-2,5-dimethyl-3(2H)-furan-3-one.

Arsenic and its compounds are considered as one of the most dangerous water pollutants which are major problem in different communities in addition to the dangerous disease. Lot of researches was done to reduce/remove Arsenic and its compounds from drinking water in the world. Various solutions have been proposed based on the results that each of them has shown different performance. In this research, introduction of these strategies and synopsis comparison of their performance was presented and the effective use of these technologies has been discussed. The main technologies of Arsenic removal include adsorption, ion exchange, chemical precipitation, filtration and reverse osmosis membrane processes. Due to the maximum removing of arsenic, the results show that reverse osmosis has the best performance and is able to remove more than 98% of arsenic and its compounds in optimal conditions.

In many poor countries, the so-called Third World, changes in agriculture is a moral necessity to reduce poverty and starvation and as a result, to establish the justice. Developing countries, where half of the population is engaged in agriculture, have the lowest income and highest rate of population growth. Plant breeding cannot lonely solve the problem of supplying enough food for the current population and millions of people that are yearly added to it. In addition, many problems, including high use of pesticides, loss of biodiversity and low efficiency threatens our food security. By eliminating the barriers of conventional plant breeding, genetic engineering provides the use of genetic resources for plant breeding and plays a significant role in preserving biodiversity and supplying food for the world. The purpose of this article is to compare transgenic crops with those products that obtained through conventional plant breeding and to evaluate the economic and environmental aspects related to transgenic crops.

The principle crops grown are soybean, cotton, maize and canola although rice and sweet potato are also on the increase. The production of Roundup Ready soybean in 1996 that being exported worldwide as basic ingredient for the feed and food industry, initiated the worldwide public debate on the environmental risks of genetically modified (GM) crops. The kinds of environmental risks include: gene flow to non-target effects, risk of superpests, superdiseases and superweeds, impact on biodiversity, antibiotic resistance markers (ARMs) from GM crops to environment and the concerns related to food safety and their impacts on human, livestock and poultry health. In addition to GM crops resistant to herbicides and pests, new-generation GM crops are now also being developed for the production of recombinant proteins, industrial enzymes and biopolymers, biofuels and micronutrients.

Plant diseases damage to agricultural crops in every year. Different approaches may be used to prevent the growth and reduce damage of plant diseases gents. Including methods is using of biological control. That is an environmentally sound and effective means of reducing plant diseases effects. Actually, the rhizosphere supports the development and activity of a huge and diversified microbial community, including microorganisms capable to promote plant growth, which could be used by these organisms for biological control of plant pathogens. Among the plant growth-promoting factors can be named as Trichoderma sp. fungus and strains of Bacillus sp. and Pseudomonas sp. had widely used in biological control of plant diseases. These biological agents make use of different mechanisms to control plant diseases, such as activate defense responses, antibiosis, stimulate plant growth, antibiotics production, increase nutrient uptake, siderophore and HCN production. Therefore, propagation and inoculation of these biological agent to plants, can decrease usage of chemical fertilizers and pesticides. Integrating mechanistic and ecological knowledge on these microorganism populations in soil will be a prerequisite to develop novel management strategies for sustainable agriculture