Microbiological quality, lipid oxidation and fatty acid composition of grass carp Ctenopharyngodon idella slices dipped in sodium acetate (0, 1 and 3%), nisin (0, 0.1 and 0.2%) or their combination during refrigerated storage of 8 days were monitored. Both nisin and sodium acetate inhibited the proliferation of total mesophile and lactic acid bacteria in dose dependent manner, but the combination treatments exhibited the higher efficacy in retardation of microbial growth. Higher concentrations of sodium acetate (3%) were more effective in preventing lipid oxidation. By the end of the storage period, higher n3 fatty acids, EPA (C20:5n‐3) and DHA (C22:6n‐3) content and lower n6/n3 ratio were found in the samples treated with 3% sodium acetate + 0.1 and 0.2% nisin. Nisin in combination with sodium acetate can therefore be used as the effective preservatives to maintain the quality of slices during refrigerated storage. PRACTICAL APLICATIONS Antimicrobial agents such as sodium acetate and nisin are found to be effective in preventing microbial growth and improving quality of food under storage condition. Treatment of slices using 3% sodium acetate in combination with 0.2% nisin was recommended as the best condition for maintaining the quality of grass carp slices stored under the refrigerated condition.

Scan to discover onlineBackground & Objective: Pseudomonas aeruginosa is an opportunistic pathogen and one of the most common causes of nosocomial infections. This bacterium's antibiotic resistance to the common fluoroquinolone antibiotics, especially ciprofloxacin, is due to mutations in the gyrA and parC genes. This study aimed to investigate the effect of the mutation in (gyrA, parC) on ciprofloxacin resistance in clinical isolates of Pseudomonas aeruginosa.Methods: A total of 140 clinical samples were collected from hospitals. The samples were identified by standard biochemical tests, and the antibiotic resistance was investigated by the disk diffusion method. DNA was extracted from 30 isolates, and PCR was performed. PCRsequencing was carried out to assess gyrA and parC mutations in drug-resistant isolates. NCBI-Blast and MEGA7 software was used to analyze the nucleotide sequences.Results: 30 clinical isolates were 80% resistant to ciprofloxacin; meanwhile, in 21 samples, mutations were observed. 87/5% of mutations were related to gyrA (Thr83 → Ile), 79/16 % parC (Ser87 → Leu), and 4/18% (Glu91 → Lys). The antibiotic resistance to ciprofloxacin and mutations in gyrA and parC genes in resistant isolates are significantly related to each other (P<0.05). Conclusion:The mutations in the gyrA and parC genes play an essential role in resistance to ciprofloxacin in clinical isolates of Pseudomonas aeruginosa.

Microorganisms such as bacteria and their derived biopolymers can be used in biomaterials and tissue regeneration. Various methods have been applied to regenerate damaged tissues, but using probiotics and biomaterials derived from bacteria with improved economic-production efficiency and highly applicable properties can be a new solution in tissue regeneration. Bacteria can synthesize numerous types of biopolymers. These biopolymers possess many desirable properties such as biocompatibility and biodegradability, making them good candidates for tissue regeneration. Here, we reviewed different types of bacterial-derived biopolymers and highlight their applications for tissue regeneration.

Background: prevalence of E. coli which produces broad spectrum Beta-lactamases in the category of animals like sheep as well as the risk of its transmission to humans have become a significant concern during recent years. The purpose of the research was to study the presence of genes blaCTX-M , blaTEM and blaSHV in E.coli isolates derived from lamb meat in butcheries of Tonekabon city, and to determine the antibiotic resistance pattern of these isolates. Materials and methods: 50 samples of lamb meat were randomly collected from butcheries of Tonekabon city and were transferred to laboratory under sterile conditions. The presence of studied genes was examined using PCR technique and proprietary primers. Antibiotic sensitivity test was conducted using Kirby's disk diffusion method. Results: Among obtained isolates, 30 isolates were identified as E. coli. All 30 isolated (100%) carried the blaCTX-M gene and lacked blaSHV. blaCTX-M was identified in 7 isolates (23.3%). 7 samples (23.3%) were positive for both blaCTX-M and blaTFM. The analysis of antibiotic resistance showed that the isolates were resistant against amoxicillin-clavulanic (86/7%), doxycycline and cephadol (10%) and tetracycline (6/7%). On the other hand, all 30 isolates (100%) were susceptible to cefotaxime and ceftazidime, and 28 isolates were susceptible to ceftriaxone. Conclusion: Isolates susceptible to antibiotics which carrying resistant genes, probably have the potential to become resistant against them. Thus logical usage of antibiotics should be considered more than before.

In this research, the capability of uranium biosorption by dried biomass of the red algae was investigated in a batch system. For the screening of the most appropriate biosorbent, they were placed in 0.5 mmol/L uranium solution with different pH for 3hrs of contact times. The obtained results showed that the species of the Gracilaria corticata (J. Agardh) are having the maximum rate of the biosorption. Sorption equilibrium was reached within 3hrs of contact time (at pH 4.5), and the results of the kinetic studies showed that the sorption of uranium followed pseudo-second order kinetic model (R 2 =0.999). The maximum uranium biosorption capacity (qmax) by Gracilaria corticata alga was 200 mg/g. The biosorption of uranium was found to be an endothermic process with ∆H˚ of +0.260 kJ/mol. The values of ∆G˚ (293K) and ∆S˚ obtained were-0.504 kJ/mol and +1.083 J/mol.K, respectively. The feasibility and spontaneous nature of the sorption process was elucidated by these values. Freundlich isotherm constants, KF and n, were 0.72 and 0.94, respectively (R 2 =0.988).