iraj rasooli

Acinetobacter baumannii is a serious challenge to the healthcare system as a multi-drug-resistant bacterium. BauA is a siderophore of A. baumannii. Oma87 has been stated as an immunogenic outer membrane protein per reverse vaccinology. Biofilm-associated protein (Bap) plays an indispensable role in biofilm formation by this pathogen and makes it resistant to a wide range of antibiotics and lethal conditions. The persistence and colonization of A. baumannii can be prevented by raising antibodies against BauA, Oma87, and Bap.
The recombinant proteins BauA, Oma87, and Bap were expressed and purified and injected subcutaneously in single and/or in combination forms to BALB/c mice and then they were challenged intraperitoneally with a lethal dose of 50% A. baumannii ATCC19606. The serum of combined mice was injected intravenously through the tail vein to create passive immunity in non-immune healthy mice. The mice's spleen, liver, and lung tissues were examined to check the bacterial load.
Oma87 and Bap in combination with BauA in the mouse model brought about significant immunity. Antibodies produced in mice successfully detected and bound the combination of antigens in the mouse model. After immunizing and challenging mice with Acinetobacter baumannii ATCC19606 admixed with mucin 100%, the survival rate was monitored. Passive immunization using the sera of mice immunized against Oma87 and BauA as well as BauA and Bap yielded 85.7% survival.
The combination of BauA with Oma87 and Bap brought about higher protectivity against A. baumannii infection than their individual administration.

Pseudomonas aeruginosa is one of the most common opportunistic bacteria causing nosocomial infections, which has significant resistance to antimicrobial agents. This bacterium is a biofilm and alginate producer. Biofilm increases the bacterial resistance to antibiotics and the immune system. Therefore, the present study was conducted to investigate the biofilm formation, alginate production and antimicrobial resistance patterns in the clinical isolates of P. aeruginosa.

  One hundred isolates of P. aeruginosa were collected during the study period (from Dec 2017 to Jul 2018) from different clinical samples of the patients admitted to Milad and Pars Hospitals at Tehran, Iran. Isolates were identified and confirmed by phenotypic and genotypic methods. Antimicrobial susceptibility was specified by the disk diffusion method. Biofilm formation and alginate production were measured by microtiter plate and carbazole assay, respectively.

Sixteen isolates were resistant to all the 12 studied antibiotics. Moreover, 31 isolates were Multidrug-Resistant (MDR). The highest resistance rate was related to ofloxacin (36 isolates) and the least resistance was related to piperacillin-tazobactam (21 isolates). All the isolates could produce the biofilm and alginate. The number of isolates producing strong, medium and weak biofilms was equal to 34, 52, and 14, respectively. Alginate production was more than 400 μg/ml in 39 isolates, 250-400 μg/ml in 51 isolates and less than 250 μg/ml in 10 isolates.

High prevalence of MDR, biofilm formation, and alginate production were observed among the clinical isolates of P. aeruginosa. The results also showed a significant relationship between the amount of alginate production and the level of biofilm formation.

The SARS-COV-2 is a non-segmented positive-sense RNA virus that belongs to the genus Beta Coronavirus. The envelope-anchored trimeric spike protein on the virus surface is considered to be the key protein for the viral entry into the host cells. The angiotensin-converting enzyme 2 (ACE2) is reported to be the effective human receptor for SARS-COV-2. ACE2 receptor can be prevented by neutralizing antibodies such as m396 targeting the virus receptor-binding site.

Considering the importance of computational docking, and in silico affinity maturation we aimed at finding the important amino acids of the m396 antibody. These amino acids were then replaced by other amino acids to improve antibody-binding affinity to receptor-binding domain (RBD) of the SARS-COV-2 spike protein. Finally, we measured the binding affinity of antibody variants to the antigen.

Our findings disclosed that several variant mutations could successfully improve the characteristics of the antibody binding compared to the normal antibodies.

the antibodies developed may be possible candidates for stronger affinity binding to antigens.

Klebsiella pneumoniae is one of the most important bacteria that cause nosocomial infections. This opportunistic pathogen has a high potential for antibiotic resistance and can generate a thick layer of biofilm. Nowadays, antibiotic resistant strains are emerging and widely spreading worldwide. Thus, it is necessary to combat drug-resistant strains through the use of novel drugs (such as medicinal plants).

This study aimed to evaluate the in vitro antibacterial activity of Satureja rechingeri Jamzad, S. khuzestanica Jamzad, S. bachtiarica Bunge, and S. mutica Fisch. & C.A.Mey. essential oils against K. pneumonia ATCC 700603.

For evaluation of the minimal inhibitory concentration (MIC) of essential oils, broth microdilution method was used. The microtiter plate assay method was used for the assessment of anti-biofilm activities of sub-MIC value of essential oils. Colorimetric and Iodometric assays were used for determination of urease and beta-lactamase activity.

According to data collected, the MIC value of essential oils was 4096 µg/mL. sub-MIC value of essential oils inhibited biofilm formation and urease activity of K. pneumoniae. However, S. khuzestanica had more activity. None of the essential oils caused a significant decrease in beta-lactamase activity of K. pneumoniae.

Based on our analysis S. khuzestanica had a good antibacterial, anti-biofilm activities and urease inhibitory effects against K. pneumoniae, but additional studies are required to investigate the exact mechanisms of the antibacterial action and functions of this phytocompound.

  Acinetobacter baumannii (A. baumannii) is a bothersome fatal patho-gen, particularly in healthcare system. Persistence and successful invasion of A. baumannii in vertebrate host cells largely depends on iron acquisition methods. Sidero-phore molecules and Iron-Regulated Outer Membrane Proteins (IROMPs) are the two essential members of iron acquisition system. Siderophores are secreted by bacteria to bind peripheral ferric iron and the IROMPs are expressed at the bacterial outer membrane as the receptor of ferric-siderophore complex. BauA is the corresponding siderophore receptor of A. baumannii. In this study, an attempt was made to assess the immunogenicity of antigenic domains of BauA which could be effective in iron uptake restriction and protection against bacterial invasion of the host cells. The antigenic domains of bauA were amplified from A. baumannii ATCC-19606. The PCR products were ligated into pET32a and expressed in Escherichia coli (E. coli) BL21 (DE3). Purification of recombinant domains was done by Nickel-Nitri-lotriacetic Acid (Ni-NTA) affinity chromatography. The recombinant domains were injected into BALB/C mice separately and in combination. Sero-reactivities of the recombinant proteins and mouse challenge tests were carried out. The antibodies raised in mice could successfully recognize and bind antigenic domains. Passive immunization studies accomplished by immune rabbit serum inhibited the establishment of infection in mice. The results adapted from the present study disclose the protective role of functional domains of BauA, especially the cork domain, suggesting a novel recombinant immunogen candidate.

FSH is a heterodimeric glycoprotein that performs an important role in the regulation of reproductive processes. Over the past decades, injectable gonadotrophins have played a leading role in the treatment of infertility. The production of FSH in the country is one of the main goals around this drug. The aim of this study was to produce a semi- industrial recombinant FSH.   In this research study, the FSH gene contained within the pVITRO2-neo-mcs vector was transfected into the cell line of CHO after transformation in DH5α and plasmid purification. The amount of FSH in cell supernatant was measured by ELISA. The FSH protein was purified by HPLC. The presence of FSH protein after purification was confirmed by SDS-PAGE and Western blotting methods. Finally, the clinical effects of purified FSH on the ovary in the rat model were investigated.   The expression of the protein was determined by ELISA test at 450 nm that was 43.538 mIU/ml. In the HPLC purification step, the FSH peak was observed at a time interval of about 7.9 minutes, and the purification efficiency was 70%. The existence of a 45 KDa band on the pvdf membrane was confirmed after western blotting of FSH.  Increasing the weight of the ovary after the injection has confirmed the functionality of the protein.   At present, the production of recombinant hormone is one of the basic needs of every country. In order to arrive at this aim, a long-term planning is required. We are trying to pave the way for producing human FSH hormone as an effective recombinant drug in the treatment of infertility.

Adhesion to host cells is an important and critical feature of Acinetobacter baumannii pathogenesis. OmpA, ABAYE1319-CsuA/b, and ABAYE2132 are highly prevalent and conserved fimbrial proteins; ABAYE1859 and ABAYE0304 fimbrial antigens are the factors described as novel vaccine candidates against multidrug-resistant (MDR) A. baumannii.
The current study aimed at investigating the significance of A. baumannii fimbrial and outer membrane proteins A (OmpA) in adherence to human epithelial cells. Antibiotic resistance was determined by the broth microdilution method. Phenotypic identification of isolates producing ESBL (extended-spectrum beta-lactamase) was conducted using double-disc synergy test (DDST). The virulence factors were detected by the polymerase chain reaction (PCR) in 100 non duplicate clinical isolates of A. baumannii; 18 clinical isolates were selected for adhesion assay based on antibiotic resistance and PCR results.
The current study results showed that ABAYE2132, ABAYE0304, and ABAYE1319- CsuA/B had significant correlation with cell adhesion (P ≤ 0.05). There was no significant correlation between cell adhesion and ABAYE1859 (P ≥ 0.05). ABAYE2132 was the most effective factor in cell adhesion. It was also observed that cell adhesion rate reduced with the increase of fimbrial proteins.
The current study findings suggested that different products and structures of A. baumannii, most still unknown, play a pivotal role in pathogen-biotic reactions. Better exposure of some non-pili adhesins or other biofilm forming factors could be a reason for this phenomenon.

Artificial oligonucleotides like DNA or RNA aptamers can be used as biodiagnostic alternatives for antibodies to detect pathogens. Comparing to antibodies, artificial oligonucleotides are produced easily at lower costs and are more stable. Neisseria meningitidis, the causative agent of meningitis, is responsible for about 1% of infections in an epidemic period. Specific DNA aptamers that bind to N. meningitidis serogroup B were identified by whole-cell Systemic Evolution of Ligands by EXponential Enrichment (SELEX).
The SELEX begins with a library of labeled ssDNA molecules. After six rounds of selection and two rounds of counter-selection, 60 clones were obtained, of which the binding efficiency of 21 aptamers to the aforementioned bacterium was tested by flow cytometry.
The aptamers K3 and K4 showed the highest affinity to N. meningitidis serogroup B and no affinity to N. meningitidis serogroups Y, A, and C, or to other meningitis causing bacteria. The dissociation constant (Kd value) for K3 and K4 were calculated as 28.3 ± 8.9 pM and 39.1 ± 8.6 pM, respectively. K3 aptamer with the lowest Kd was chosen as the main aptamer. K3 could detect N. meningitidis in patients’ cerebrospinal fluid (CSF) samples and in CSF from healthy volunteers inoculated with N. meningitidis serogroup B (ATCC 13090) at 200 and 100 CFU ml-1, respectively.
The findings suggest the application of the developed aptamer in specific detection of N. meningitidis serogroup B amongst a group of meningitis causing bacteria.

Due to the importance of Pseudomonas aeruginosa in severe inpatient infections and high mortality, the need for an efficient vaccine against these bacteria is increasing. In this regard, the general outer membrane porin of the most problematic microorganism P. aeruginosa, outer membrane protein F (OprF), is a good vaccine candidate.
The databank of NCBI was used to retrieve protein sequences recorded for OprF in P. aeruginosa.The current study aimed at investigating the conservation of the OprF in 150 reference sequences, clinical, and environmental strains of P. aeruginosa from different countries via bioinformatic tools.T-COFFEE and PRALINE software were used for alignment.
Of these, 134 strains were isolated from clinical specimens and other strains from environmental samples. Evaluation of alignment by the mentioned software clearly showed that this protein was conserved. Antigenicity and grand average of hydropathicity were favorable.
Conservation of OprF in all pathogenic and environmental strains of P. aeruginosa indicated that it can be considered as a good immunogen; however, the protectivity of OprF should be validated experimentally.

Biodegradable polyesters are candidates for the development of environmental friendly plastics. Poly-β-hydroxybutyrate (PHB) is a type of polyester from the hydroxyalkanoates family, synthesized by bacteria as an intracellular material and accumulated as granules in the cytoplasm. The aim of this study was to isolate Poly β-hydroxybutyrate over producing bacteria and optimize the production medium. A variety of PHB-accumulating bacterial strains were isolated from Kermanshah oil refinery sludge in Iran. Poly-β-hydroxybutyrate-producing bacterial strains were confirmed by the gas chromatography method. The strain with the highest rate of PHB production was selected. Use of sugar cane molasses, a by-product of the sugar refinery industry, was investigated for the production of PHB. Plackett-Burman statistical method was employed to obtain factors in cell growth and PHB production. Optimization by the Response Surface Method (RSM) was done via two carbon sources, glucose and molasses. In the present study, 21 of 63 strains isolated from the refinery oil sludge produced PHB, seven of which were over producers. Poly-β-hydroxybutyrate production was analyzed by Sudan Black B staining, spectrophotometric and gas chromatography (GC) methods. The strain with the highest rate of PHB production was used to optimize the culture medium. Fifteen factors were analyzed in PHB production by the Plackett-Burman method to find the most effective factors. Five important factors were optimized by RSM. Molasses were used as a cheap source of carbon. The maximum PHB obtained from molasses was 6.62 g/L. The phenotypic and 16S rRNA biotyping tests led to the identification of the isolate as Bacillus coagulans. The results suggest that B. coagulans is a good candidate for the fermentative production of PHB.

Azotobacter is a diazotroph bacterium reported to possess various plant growth-promoting characteristics. The aim of this study was to isolate Azotobacter strains capable of fixing nitrogen and effectively hydrolyzing both organic and inorganic Pi compounds. In this study, soil samples collected from a diverse range of slightly alkaline soil types were screened for Azotobacter isolates. The inorganic and organic phosphate solubilization potentials of twenty competent phosphate solubilizing Azotobacter isolates were assessed. Variations were noted in the solubilization potentials. Three isolates, identified as Azotobactervinelandii strains O2, O4 and O6, were able to fix atmospheric N2 effectively. The nitrogenase activity of these isolates ranged between 158.6 and 326.4 C2H4h-1vial-1 (ethylene). Bacterial growth rates and phosphate solubilization activities were measured quantitatively under various environmental conditions. A close association was evident between phosphate solubilizing ability and growth rate as an indicator of active metabolism. All three phosphate solubilizing bacteria (PSB) were able to withstand temperature as high as 45°C, high concentration of NaCl (upto 5%) and a wide range of initial pH from 5 to 10 while hydrolyzing phosphate compounds actively.Azotobactervinelandii strains O2, O4 and O6 are superior candidates for biofertilizers that may result in the reduction of chemical nitrogen and phosphate fertilizers leading to increase crop production.

Typhoid fever is a dreadful disease of a major threat to public health in developing countries. Vaccination with bacterial immunodominant components such as surface proteins may prove as a potent alternative to live attenuated vaccines. InvH, an important part of needle complex in type three secretion system (TTSS) plays important role in efficient bacterial adherence and entry into epithelial cells. In this work we used a 15 kDa recombinant InvH protein of Salmonella enteric serovar Enteritidis to provoke antibody production in mouse. The mice were immunized by recombinant InvH and challenged with Salmonella typhi. Histopathology of spleen and liver were studied. The immunized mice showed a significant rise of antibody after the second booster. The immunization induced protection against high doses of S. typhi. The bacterial challenge with sera showed significant protection against challenge dose of 2×109 CFU. Immunized sera reacted with S. typhi markedly. Immunoreaction of bacterially infected sera and InvH protein was significantly higher than the control group. Bacterial loads of S. typhi in spleen was more than liver. Decreased bacterial load was evident in immunized mice after 7 days. Histological examination of the liver showed the immunized mice liver remained unaffected. Efficacy of the virulence protein, InvH, in inhibition of this phenomenon by active immunization was shown here. It may be concluded that InvH, as an antigen, can develop protection against S. typhi infections. InvH may be exploited in protective measures as well as a diagnostic tool in Salmonella infections.

Acinetobacter baumannii is a Gram-negative, non-motile aerobic bacterium known as a nosocomial pathogen resisting often to broad range of antibiotics. The pathogen is a serious agent of mortality and morbidity in hospital particularly among immunocompromise patients. Treatment and control of its infections is complicated owing to its high antibiotic resistance, survival in various environmental conditions and utilization of wide range of nutrient sources. Early detection of the pathogen in established infections is pivotal for controlling the infections. Culture and biochemical test are current methods for detection of the bacterium taking 2-5 days time. Hence, a new rapid specific affordable diagnostic test is needed. Development of such test depends on a suitable biomarker without any cross reactivity with other bacteria. Accordingly, aim of the study is to unveil of a 34.4 KDa outer membrane protein (OMP) introduced by Islam et al. in A. baumannii ATCC19606. In the current study, we harnessed various bioinformatic servers to screen whole proteome of the bacterium. Properties critical to the screening include: molecular weight, localization, topology, homology, antigenicity and allergenicity of proteins. Three proteins were found as suitable candidate molecular weight as well as localization points of view. BLAST searches, antigen probability predictions and other analyses led to selection of one protein as the best specific antigen of A. baumannii. The in silico analyses unveiled the best candidate protein vide accession number ZP_05827218.1.

Acinetobacter baumannii (A. baumannii) has a good potential to colonize on various surfaces. As a virulence factor, adhesion to surfaces is the first step in colonization. The Two-Partner Secretion System (TPS) proteins are key factors for bacterial attachment. The purpose of this study is to identify and study the role of this family of proteins in adhesion of A. baumannii to human epithelial cells. Gene homologues that encoded the TPS were analyzed by bioinformatics tools and the primers were designed accordingly. The constructs synthesized in the pET22b vector were transferred to BL21(DE3). The transformed cells were named FhaB1 and FhaB2. The protein expression on the cell membrane was studied in addition to bacterial adhesion and biofilm formation by recombinant strains, A. baumannii and E.coli BL21(DE3). Bioinformatic studies showed the bacterial potential of producing two exoproteins (FhaB1 and FhaB2). Expression of the recombinant proteins on the outer membrane was confirmed by Western Blot Analysis and whole cell ELISA. The results revealed an association between the recombinant cells and bacterial adhesion and biofilm formation. FhaB1, FhaB2 and A. baumannii exhibited enhanced adherence to human lung epithelial cells compared to E.coli BL21(DE3) TPS in A.baumannii is of adherence and colonization factors and is one of the bacterial virulence factors.

Acinetobacter baumannii (A. baumannii) is a major hospital pathogen with a high capacity to resist most common anti-microbial agents. A. baumannii is the etiologic agent for various illnesses including pneumonia، meningitis، and bloodstream infections. Biofilm associated proteins (Bap) are specific cell surface proteins essential for the formation of biofilm and play a main role in its pathogenicity. Previously، we have studied various regions of this protein. Considering different criteria، some regions were introduced as conserved and immunogenic. The immunogenicity of one of those regions pertaining to amino acids 706-1076 previously examined has shown that its expression triggers high antibody levels when injected to mice thereby protecting the animals against the bacterium. The present study examines region 4 of the Bap protein in order to validate the previous bioinformatics studies and its immunogenicity. In order to obtain immunity against this pathogen، a 1620 bp gene from Bap was amplified and cloned in pET32a. This region from Bap was cloned، expressed and verified by monoclonal antibodies. BALB/c mice were immunized by subcutaneous injection of the pure recombinant protein. Mice immune response was determined by ELISA. High titer of raised antibodies implied that the recombinant protein was a strong antigen and immunogen. The results indicate that this protein can be a suitable choice for developing a new recombinant vaccine against A. baumannii.

Many food products are perishable by nature and require protection from spoilage during their preparation, storage and distribution to give them desired shelf-life. Because food products are now often sold in areas of the world far distant from their production sites, the need for extended safe shelf-life for these products has also expanded. Currently, there is a strong debate about the safety aspects of chemical preservatives since they are considered responsible for many carcinogenic and teratogenic attributes as well as residual toxicity. For these reasons, consumers tend to be suspicious of chemical additives and thus the demand for natural and socially more acceptable preservatives has been intensified. One such possibility is the use of essential oils (EOs) as antibacterial additives. In the production of food it is crucial that proper measures are taken to ensure the safety and stability of the product during its whole shelf-life. In particular, modern consumer trends and food legislation have made the successful attainment of this objective much more of a challenge to the food industry. EOs comprise a large number of components and it is likely that their mode of action involves several targets in the bacterial cell. It is most likely that their antibacterial activity is not attributable to one specific mechanism but that there are several targets in the cell. The potency of naturally occurring antimicrobial agents or extracts from plants, ranges of microbial susceptibility and factors influencing antimicrobial action and their antioxidativeproperties, aimed at food preservation, are reviewed in this article. Methods employed for estimation of inhibitory activity, mode of action and synergistic and antagonistic effects are evaluated. Hence, it is recommended that more safety studies be carried out before EOs are more widely used or at greater concentrations in foods that at present. There is therefore scope for new methods of making food safe which have a natural or ‘green’ image.

Shigella and Escherichia belong to the Enterobacteriaceae family which are the cause for most of the diarrheal cases in the world. Shigella can cause bacterial dysenteries and shigellosis. One of the most effective proteins for pathogenesis is invasion plasmid antigen C (IpaC). Other bacteria like Enterotoxogenic (ETEC), Enterohemorrhagic (EHEC), and E.coli can also cause diarrhea and produce intestinal disorders. Colonization factor antigen I (CFA/I), a critical virulence protein for these infections, has two subunits i.e. CfaB and CfaE. EHEC Attachment of bacteria is the main step of infection with intimin playing the key role in this function. This study was designed to elicit protection against the majority of diarrheal pathogens via development of polyvalent vaccine against Shigella, ETEC and EHEC. In silico techniques are as best tools to design new vaccines. For this purpose the immunogenic epitopes of CfaB, IpaC and Intimin were identified through bioinformatic tools and were then selected as major antigens to construct a chimeric protein (CII). The humoral and cellular immunities were analyzed bioinformatically. Prediction of allergens and mapping of IgE epitopes were carried out. The bioinformatic analysis showed each domain was folded separately in fusion structure. CII had many T and B cell epitopes in both linear and three-dimensional structures. This prediction of the chimeric construct had the potential to induce CD4+ and CD8+ immune responses against these pathogens. In addition CII could be accessible to surveillance by the immune system in mouse and human. In conclusion, in silico analysis showed that this chimeric protein can be used as a vaccine against Shigella, ETEC and EHEC simultaneously.

Enterohemorrhagic Escherichia coli (EHEC) O157:H7 is an important enteric pathogen in human causing bloody or nonbloody diarrhea, which may be complicated by hemolytic uremic syndrome (HUS). Cattle are an important reservoir of EHEC. This research aims at vaccination with a divalent chimer protein composed of EspA120 and Intimin 282 and its preventive effect of EHEC O157 colonization in mice rectal epithelium. A divalent recombinant EspA-Intimin (EI) protein containing EspA120 and Intimin280 attached with a linker was amplified from a trivalent construct and cloned in pET-28a (+) vector. The immunization was conducted in mice after expression and purification of the recombinant EI (rEI). Mice subcutaneously immunized with rEI, elicited significant rEI specific serum IgG antibodies and showed significantly decreased E.coli O157:H7 shedding compared to the control group. The chimeric recombinant protein induced strong humoral response as well as protection against oral challenges with live E.coli O157:H7.

Aspergillus species produce the highly toxic and carcinogenic metabolite, Aflatoxin B1 (AFB1), on food and agricultural commodities. Some natural products are known to inhibit aflatoxin production.. With the aim of controlling aflatoxin production, the essential oils of Cuminum cyminum L. from the best known regions of Iran i.e. Alborz Mountain and Kerman region, were obtained by hydrodistillation.. Antifungal activities of the oils to inhibit growth and aflatoxin productivity of A. flavus PICC-AF39, A. flavus PICC-AF24, and A. parasiticus NRRL-2999 were studied. Minimal inhibitory (MIC) and minimal fungicidal (MFC) concentrations of the oil were determined. Sub-MIC was selected for the measurement of aflatoxins B and G concentration. Samples were analyzed either using a high performance liquid chromatography (HPLC) method with some minor modifications. Aflatoxins (AFs) were determined by reverse-phase HPLC and fluorescence detector with post column derivatization (PCD) involving bromination.. A significant reduction in Aflatoxin production was noted which was not due to the inhibitory effect but because of antifungal property of the oil. Interestingly, the oil promoted toxin production for the reasons yet to be investigated. The extent of aflatoxin production was dependent on the concentration of essential oil used. All toxin-producing fungi in this study produced higher amount of aflatoxin at low concentrations of the oil. 400 ppm concentration of C. cyminum L. from Alborz Mountain increased aflatoxin production to over fourfold. Aflatoxin productivity was declined at high concentration of the oil.. Antimicrobial and antitoxigenic properties of natural products need a firmly established criterion before they could be offered to application..

Resistance to antibiotics is a clinical problem. Cyanobacteria have many more antibiotic productions. Nowadays, combinations of antimicrobial compounds are used.. The current research studied antimicrobial properties of Leptolyngbya.. Chloroform extracts of Leptolyngbya sp. were prepared. Antimicrobial effects of these extracts were evaluated singly and in combination with antibiotics against various microorganisms. Growth optimization, antimicrobial activity and their correlations were studied.. C. leptolyngbya had antimicrobial activity individually and in synergy with antibiotics against gram-positive and gram-negative bacteria. The highest activity of the chloroform extract was on gram positive strains and its effects on fungi were moderate, but it had a little effect against gram negative ones. Phosphate salt was the most important factor for growth and antibacterial activity in C. leptolyngbya.. Optimization of medium composition and synergistic antimicrobial activity on the cyanobacteria could lead to production of effective antimicrobials..

Enterohemorrhagic Escherichia coli (EHEC) O157:H7 has been recognized as a major food borne pathogen responsible for frequent hemorrhagic colitis and hemolytic uremic syndrome in humans. Cattle are important reservoirs of E. coli O157:H7, in which the organism colonizes the intestinal tract and is shed in the feces. Vaccination of cattle has significant potential as a pre-harvest intervention strategy for E. coli O157:H7. The aim of this study was to evaluate active and passive immunization against E. coli O157:H7 using a recombinant protein. The recombinant FepA protein induced by IPTG was purified by nickel affinity chromatography. Antibody titre was determined by ELISA in FepA immunized rabbits sera. Sera collected from vaccinated animals were used for bacterial challenge in passive immunization studies. The results demonstrate that passive immunization with serum raised against FepA protects rabbits from subsequent infection. Significant recognition by the antibody of ferric enterobactin binding protein may lead to its application in the restriction of Enterobacteriaceae propagation.

Enterohemorrhagic Escherichia coli (EHEC) O157:H7 causes hemorrhagic colitis. The most important reservoirs of this bacterium are domestic ruminant, particularly the cattle. Although it has low prevalence, the severity of consequent diseases of this bacterium brings concerns to develop effective vaccines. This bacterium is able to produce attaching-effacing (A/E) lesions in intestinal epithelial cells and several genes have been implicated in A/E formation. EspA is part of the type III secretion systems that could deliver Tir (translocatedintimin receptor) to the host epithelial cell.. The eae gene encoded intimin protein which is essential for colonization of the mucosa and A/E lesions formation by docking to the Tir.. Based on these concepts, the immunogenic part of eae and tir genes were constructed and fused together by a linker. The synthetic constructs were subcloned on pET28a + vector and expressed in E. coli BL21DE3. The purified chimeric recombinant protein was injected to mice and the rising antibody was assessed.. The results showed that the chimeric recombinant protein induced strong humoral response as well as protection against live oral challenges using E. coli O157:H7.. The rIT could reduce bacterial shedding effectively..

Acinetobacter baumannii is an opportunistic pathogen that causes serious infections in humans bycolonization of medical devices. The capacity of this pathogen to persist in hospital settings could be due to its ability to form biofilms. In the present study we evaluated the effect of antibodies against one of surface components of A.baumannii on in vitro biofilm formation. The 1113 bp fragment of Bap (biofilm associate protein)gene from A. baumannii genome was amplified and cloned. The recombinant protein was expressed and purified and used to raise antibodies in mice.Antibody titer was evaluated by ELISA. In vitro biofilm inhibition was evaluated using the mice sera. Injection of Bap subunit resulted in high titers of antibody. Immunized mice serum had significant (P<0.001) inhibitory effect on biofilm formation. In vitro inhibition of biofilm formation by A. baumannii was studied at 1:50 concentrations of immunized and unimmunized mice sera. Immunized mice serum had significant (P <0.001)inhibitory effect on biofilm formation Adsorption of antibodies to Bap might interfere with bacterial adhesion to the surface. These antibodies were found to be potent biofilm inhibitors.

Infection with Escherichia coli O157:H7 rarely leads to bloody diarrhea and causes hemolytic uremic syndrome with renal failure that can be deadly dangerous. Intimin, translocated Intimin receptor (Tir), and enterohemorrhagic E. coli (EHEC) secreted protein A (EspA) proteins are the virulence factors expressed by locus of enterocyte effacement locus of EHEC. This bacterium needs EspA as a conduit for Tir delivery into the host cell and the surface arrayed Intimin, which docks the bacterium to the translocated Tir. Here we used triplet synthetic gene (eit) which was designed from three genes: espA coding EspA 120 lacking 36 amino acids from the N-terminal of the protein, eae coding Intimin constructed of 282 amino acids from the C-terminal and tir coding Tir 103, residues 258-361 which interacts with Intimin. The multimeric gene was cloned in two eukaryotic vectors pAAV-multiple cloning site-green fluorescent protein and pCI-neo. The pAAV was used for gene expression assay in cell line 293T and pCI-neo-EIT (EspA, Intimin, Tir) was used as DNA vaccine in mice. Test groups were injected intramuscularly with pCI-neo-EIT four times and mice control group was injected under the same conditions with PBS or pCI-neo vector. The titration of serums showed that BALB/c mice were successfully immunized with DNA vaccine compared to control groups and also they were protected against challenges of live oral using E. coli O157:H7. The results suggest that the DNA vaccine could induce protective immunity either alone or in combination with purified antigens to reduce EHEC infection.

Aflatoxin B1 (AFB1) is a highly toxic and hepatocarcinogenic metabolite produced by Aspergillus species. Some natural products are known to kill fungi and destroy toxins and toxin-producing agents. The purpose of this study is to provide experimental data on the antifungal activity of cumin oils and their components that could be considered suitable for application in foods and drugs. The essential oil (EO) of Cuminum cyminum L. collected from Alborz mountain, Iran, was obtained by hydro-distillation. The oil was analyzed by gas chromatography (GC) and chromatography/mass spectrophotometry (GC/MS). The antifungal activity of the oil was studied with regard to the inhibition of the growth of Aspergillus flavus PICC-AF39, Aspergillus flavus PICC-AF24, Aspergillus parasiticus NRRL-2999 and Aspergillus niger. The minimal inhibitory (MIC) and minimal fungicidal (MFC) concentrations of the oil were determined. α–Pinene (29.2%), limonene (21.7%), 1,8-cineole (18.1%), linalool (10.5%), linalyl acetate (4.8%), and α-terpineole (3.17%) were the major components of the essential oil from C. cyminum L., and the oil showed a strong inhibitory effect on fungal growth. Essential oils could be safely used as preservatives in pharmaceuticals as well as health and food products to protect them against toxigenic fungal infections.