فصلنامه ایمنی زیستی
سال سیزدهم شماره 2 (تابستان 1399)

Streptomyces is the most important bacterial genus known to produce secondary antibiotic compounds. Considering the speed of bacterial resistance spread, it becomes more important to study less used compounds. Aminoglycosides disrupt the function of the target microorganism by acting on the protein-synthesis process. Paromomycin is an aminoglycoside that acts on a wide range of gram-positive, gram-negative bacteria and protozoa. Today, this antibiotic is mostly used in the treatment of visceral leishmaniasis. The main producer of paromomycin is S. rimosus NRRL 2455. Taking these antibiotics in high doses can cause widespread complications in the heart, kidneys, and auditory system, but in low doses and in combination with other types of antibiotics, it can significantly inhibit the growth of multidrug-resistant (MDR) bacteria. According to this information, it is important to know the factors that increase production and to understand the relationship between the structure and performance of this antibiotic. The aim of this study was to collect useful and up-to-date information about paromomycin, production conditions and the importance of this antibiotic in the treatment of bacterial MDR infections.

As the new coronavirus infection (Covid-19) spreads and has become epidemic, according to the World Health Organization (WHO), it has involved us with figures and statistics. How many new items? How many countries? Is the infection curve growing? What is the mortality rate? While the extent of the disease is still unclear, the economic impact of the virus outbreak is of great concern. The effect of the virus on the food supply chain is also significant. Will we be exposed to food shortages or price jumps? How can these effects be minimized? Can the avoidance of monopolies, price monitoring, and the protection of the vulnerable through social security networks limit the spread of the virus? What is the role of food safety in preventing the spread of the virus and its effects on food security? Can raising awareness about food safety and compliance with health regulations, including workerschr('39') rights, roles and responsibilities, ensuring that people do not transmit the virus along the food supply chain be effective in ending the disease and its profound effects on food security?

Heavy metals and petroleum entering the marine environment have adverse effects on aquatic species. The impacts of these compounds on living organisms depend on the type of contaminant and species. In recent decades, biological methods to control and remove heavy metals and petroleum hydrocarbons in the environment have come into focus. Bacterial elimination of pollutants is one of such methods. In this study, the isolation and purification of bacterial species from Persian Gulf sediments led to the identification of Ochrobactrum sp. and Pseudomonas sp. Maximum growth of Ochrobactrum sp. was observed at a concentration of 100 mg/l and the bacterium could also remove 66.5% of the lead metal.  The maximum optical density of Pseudomonas sp. obtained on the ninth day of incubation was 0.852. Eventually, Pseudomonas sp. could degrade 98.48 % of anthracene after 5 days. The decrease of bacterial function in the high concentrations of lead and anthracene can be associated with the destructive impact of these pollutants on the protein synthesis and disruption of enzyme activities in microorganisms.

The outbreak of the new coronavirus infection and the causative agent of Covid-19 poses significant threats to national and international health and the economy. In this article, we have reviewed some treatment options related to coronavirus infections as well as some viral infections containing ribonucleic acid (RNA-VIRUS) and found that general and specific treatments for coronavirus should be used in the fight against Covid-19 disease. The study also suggests that the nutritional status of each infected patient should be assessed before starting public treatment. Given that recent research has shown an increase in virus transmission and infection in patients with deficiencies in vitamins C and A, diets containing these vitamins along with vitamins E and D, as well as omega-3 including protectin D1, could potentially be used as promising options to prevent lung infection with coronavirus. Selenium, zinc and iron as effective elements in improving the function of the immune system may be effective in inhibiting recurrent respiratory infections. Use of inhibitors of coronavirus enzymes and bioactive compounds such as flavonoids, chloroquine, emodin, promazine, diarylheptanoids and cinanserin can be used as specific interventions.

The purpose of this article is to evaluate the effect of oligosaccharide prebiotic consumption on reducing the risk of diseases such as diabetes, high blood pressure, fat and bowel cancer. In people of different ages, consumption of oligosaccharide prebiotics has played a very effective role in intestinal function. In general, it can be noted to evaluate the extent of decreased glucose uptake in diabetics, fat loss, decreasing sensitivity in breastfed infants and increase the excretion and relief of chronic constipation in the elderly. Also in research on improvement intestinal function, results of oligosaccharides in women and men have been associated with improved performance and reduce abdominal pain, bloating and change intestinal function.

The SARS-CoV-2 viral infection pandemic has altered health and disinfection protocols in many public places. Swimming pools are one of the most dangerous places for COVID-19 outbreaks. This article examines the mechanism and rate of transmission of the SARS-CoV-2 virus and its resistance to treatment systems to purify swimming pool water by chlorine and UV. This review is based on reports and protocols from organizations and centers such as the World Health Organization (WHO) and the US Centers for Disease Control and Prevention (CDC). Studies show that free chlorine with a concentration of 1-3 ppm along with the implementation of a well-written program for the treatment system with proper operation will inactivate and remove the COVID-19 virus from the pool water. In addition, maintaining social distance and reducing the number of swimmers by 50% of the usual number can significantly reduce the risk of person-to-person transmission.

Potyviruses are one of the largest families of plant viruses (Potyviridae) with the most economic importance. Potyviruses have flexuous filaments and the genome consists of a positive sense single stranded RNA with 183 species. Today, biological, serological, and molecular assays are used to screen potyviruses. In this review, the application of different methods is described to the identification of potyviruses that are infected with a wide range of plants in Iran and the world. The use of primers, especially degenerate primers, has not only facilitated the rapid detection of potyviruses but also the sequencing of a part of the genome also makes the taxonomy of these viruses possible. Today, the TaqMan system has been developed and can show the number of early RNA copies of potyviruses in infected plants compared to healthy plants. Transcriptome technology demonstrates complex reactions between putative multifunctional proteins and their association with host proteins. This method is involved in the detection of molecular and physiological responses of infected plants with potyviruses as well as their evolution and phylogeny. CRISPR technology is one of the effective and novel methods for purposeful editing of the genome that is used to improve the quality and yield of plants and create new characteristics in them. This method can be used to produce resistant plants to potyviruses.