The gut microbiota can have profound effects on hosts, but the study of these relationships in humans is
challenging. The specialized gut microbial community of honey bees is similar to the mammalian microbiota,
as both are mostly composed of host-adapted, facultatively anaerobic and microaerophilic bacteria. However,
the microbial community of the bee gut is far simpler than the mammalian microbiota, being dominated by
only nine bacterial species clusters that are specific to bees and that are transmitted through social interactions
between individuals. Recent developments, which include the discovery of extensive strain-level variation,
evidence of protective and nutritional functions, and reports of eco-physiological or disease-associated
perturbations to the microbial community, have drawn attention to the role of the microbiota in bee health
and its potential as a model for studying the ecology and evolution of gut symbionts

Silver Nanoparticles included 56 % of total manufactured Nanomaterials due to its anti-bacterial properties in the world. Therefore، the release of Silver Nanoparticles to water ecosystems will make an irreparable damage to biota، especially to natural bacterial flora. The purpose of this study is to investigate the Silver Nanoparticles effects on the bacterial flora of rainbow trout skin. To ensure the quality of the Silver Nanoparticles، the ICP، Zetasizer، TEM، EDX، and Uv-vis Spectrophotometer sets were used. Also، the population’s mesophilic bacteria، psychrophile، Enterobacteriaceae and Lactic acid bacteria (LAB) of skin after 14 days kept of fish in 1، 0. 1 and control group of Silver Nanoparticle concentrations were counted by pour plate method. Results of the study showed that the fish skin LAB bacteria decreased significantly with the increase of Silver Nanoparticle concentration and mesophile and Enterobacteriaceae were less affected. Whereas، population of fish skin psychrophile bacteria significantly increased with enhancing of Silver Nanoparticles concentration. Analysis of result suggested that according to the type of studied group of bacteria، an antibacterial property of Silver Nanoparticles is selective and different.

Extracellular vesicles, naturally released from all cell types including bacteria, are of great importance in medical microbiology due to transporting a variety of biomaterials, enzymes, and virulence factors, regulating immunity, and having roles in colonization and initiation of signaling pathways. These vesicles are also secreted from microbiota in the gastrointestinal tract and affect the host through various mechanisms by causing many systematic, metabolic, and physiological changes. Nowadays, the role of these vesicles is proven in maintaining gastrointestinal homeostasis, the pathogenesis, and diagnosis of related diseases such as obesity, diabetes, cancer, inflammatory bowel disease, mental disorders, and infectious diseases. Effective use of these characteristics could be possible by modulating the microbiota and its metabolites and using extracellular vesicles derived from probiotics. Therefore, the study of these vesicles as microbiota-derived products and next generation probiotics offers a new approach in clinical studies. The present study investigates how the microbiota-derived extracellular vesicles affect the hostchr('39')s health and play underlying roles in various diseases.

Corals have a diversity of prokaryotic communities as an internal or external symbiotic . This review will examine the association between corals and their symbiotic microorganisms from the ecology and biotechnology perspective.
Material and In this study, articles were examined which indexed in Pubmed, Science Direct, Google Scholar and Scirus databases. Keywords we used included coral, symbiotic microorganisms, ecology, and biotechnology. Finally, overall of 120 articles and reports, 103 articles were evaluated by eliminating the same articles.
The Corals symbiotic microorganisms stay on in the ecological niches such as the surface mucus layer, tissue and their skeleton. They play role in the cycle of sulfur, nitrogen fixation, production of antimicrobial compounds and protect corals against pathogens. Many bioactive compounds which attributed to invertebrates such as sponges and corals in fact they are produced by symbiotic bacteria. Various metabolites produced by these microorganisms can be used as medicine. Five screening strategies including conventional screening, met genomics, genomics, combinatorial biosynthesis, and synthetic biology are used for marine microbial natural products discovery and development.
According to the collected material we can be concluded that, the ecological studies about the natural association between corals and their symbiotic microorganisms were technological prerequisite for biomedical research and they make clear the road to attainment to bioactive compounds in fauna. Also, in the first step, it is recommended that modern technology and advanced screening methods used to identification of marine organisms and then to identify secondary metabolites among them.

Biological nitrogen fixation is important for supplement of nitrogen needs of host plant. Growth chamber experiments were conducted to test the nitrogen fixing abilities of isolate of Rhizobium strains collected from 10 cities (Urmieh, Khoy, Makuee, Salmas, Mahabad, Miandoab, Tekab, Sardasht, Shahindege and Piranshar) of West Azerbaijan province in symbiotic relation with alfalfa, chickpea, clover and bean cultivars. Seedlings of test plants were inoculated with proprietary Rhizobium strains. Inoculated and control seedlings of each plants were planted in pots containing sterilized perlit. The experiment was conducted using completely randomized design with three replications. The pots were irrigated with free nitrogen Hoagland solution. Results showed that the highest number of nodule and the lowest nodule dry weight was for clover and bean, respectively.. Symbiotic of Rhizobium strain of Miandoab for alfalfa, Mahabad for clover and Urmieh for bean had the highest values for most of traits. Nitrogen fixation correlated with total dry matter, and it seems this trait may be used as an indirect criterion of nitrogen fixation. This findings imply the possibility of replacing biologically fixed nitrogen with chemical fertilizers.

Most inoculation studies have focused on free-living diazotrophs, although a few reports indicate rhizobia can act as PGPR. In order to evaluate nitrogen fixation ability of different strain of Rhizobium legominosarum biovar phaseoli in common bean, a randomized complete block design including 6 rhizobial isolates(L-100, L 41, L-75, L-216, L-54 and L-139 selected from different provinces by soil & water research institute), one nitrogen fertilizer (400 kg Urea per ha) and one control plot (without seeds inoculated and fertilizer) in four replication was carried out in two field (Dehaghan & Esfarjan) at Isfahan province in 2003. Results showed that significant differences were observed in seed and dry matter yield, total nitrogen absorption, number and weight of nodules and seed yield among seed inoculated with different strains and non-inoculated controls. In Dehaghan field, seed inoculation with L-75 strain and in Esfarjan field, seed inoculation with L-54 and L-139 strains increased dry matter yield, total nitrogen absorption, number and weight of nodules and seed yield. Results also showed that seed inoculation with some rhisobia isolates increased micronutrients absorption. In Dehaghan field, inoculation of L-216 and L-75 strains led to higher absorption of Cu and Zn. Some isolates could not promote nitrogen absorbtion.

Symbiotic bacteria associated with the root of legume plants were isolated from soil and the root nodules of alfalfa (Medicago sativaL.), chickpea (Cicer arietinum L.) and yellows alfalfa (Melilotus officinalis L.) grown in arsenic-contaminated areas in south eastern part of Kurdistan province, Iran. According to physiological and biochemical properties, isolates were identified as the members of Rhizobium and Ensifer genus. The presence of arsenic resistant system known as ars system was confirmed by amplification using primers corresponding to arsC gene. Growth rate of strains in different concentrations of arsenate was investigated in YEMB medium supplemented with 100-400 mM arsenate. Alfalfa,s isolates (AB1, AB3), chickpea,s isolates (PA2, PC2), yellow alfalfa,s isolate (YA1) and standard strain (Sinorhizobium meliloti SM117) were tolerant to 350 mM arsenate and (AB1, PA2 and YA1) isolates were moderately capable to grow at 400 mM arsenate. Among the identified strains, AB1 and PA2, were selected for greenhouse experiments. In order to evaluate the effect of arsenic contamination on legume-rhizobia symbiosis and biomass production of alfalfa and chickpea plants, an experiment was carried out based on a completely randomized design with a factorial arrangement in three replications. Experiment factors consisted of, three levels of rhizobia inoculation (with and without inoculation of AB1 and PA2) and five levels of arsenic concentrations (0. 10, 50, 75 and 100 mgkg-1 soil) under greenhouse conditions for 8 weeks. Results obtained in this study indicated that the fresh weight and dry weight of alfalfa and chickpea (shoot and root) were decreased as the arsenic concentration of the soil was increased. The results also showed that fresh and dry shoot and root weight of alfalfa and chickpea were significantly higher in rhizobia-inoculated treatments compared to non-inoculated plants.

The aim of this study was to isolate and identify a-amylase-producing bacteria present in mangrove ecosystems on Qeshm Island, Hormozgan, Iran. Samples of mangrove leaves and roots were screened for a-amylase activity using Lugol’s solution. Crude extracts were prepared of positive samples, and their a-amylase activity was determined by the Bernfeld method. The two strains with the highest activity were identified by molecular analysis of their 16S rRNA genes. a-Amylase production and activity were optimized by varying temperature and pH. 46 bacterial strains were isolated from mangrove tree leaf and root samples. Of these, 28 strains were capable of producing a-amylase. 16S rRNA gene sequence analysis of two strains with the highest enzyme production identified them as Bacillus sp. strain HR10 and Bacillus sp. strain HR11. The optimum temperature for enzyme production was 35 and 30 °C for strains HR10 and HR11, respectively, and the optimum pH was pH 8 for both strains. The highest enzyme activity was observed at 70 °C and 60 °C for the HR10 and HR11 strains, respectively, and the optimum pH was pH 8 for both strains. In conclusion, we have shown that bacteria isolated from mangrove leaf and root samples are potential source of a-amylases, tolerating a wide range of temperature and pH. Such a-amylases may be of interest for use in environmentally friendly industries.