nasrin noohi

Cultural heritage is always subject to biodeterioration by microorganisms, and their control and containment are essential. Metal nanoparticles can be a good option to solve this problem. Following the production and identification of silver and zinc nanoparticles by the green method, in this study, we aimed to evaluate the antimicrobial activity of the synthesized nanoparticles and their toxic effect on normal human cells for use in the field of cultural heritage. To investigate the antimicrobial effect of silver and zinc nanoparticles, 4 bacterial strains, B. subtilis, Ps.aeruginosa, B. licheniformis and Micrococcus and 5 fungal strains, Aspergillus, Penicillium Alternaria, Chaetomium, and Cladosporium were tested. For this purpose, agar diffusion and liquid dilution tests (to determine MIC) were performed, and in the next step, MBC (for bacteria) and MFC (for fungi) were determined. Also, the cytotoxicity of nanoparticles was evaluated on HDF cell lines (normal skin cells) using the MTT method. Silver nanoparticles showed antimicrobial effect against all tested bacterial and fungal strains. Out of the 5 fungal strains studied, only Chaetomium fungus was sensitive to zinc nanoparticles, On the other hand, all tested bacterial strains except Ps. aeruginosa were sensitive to zinc nanoparticles. Silver nanoparticles showed concentration-dependent cytotoxic activity against HDF, but zinc nanoparticles did not show a toxic effect on HDF cells. Among the two investigated nanoparticles, silver nanoparticles have a high potential to be used as an antimicrobial agent. However, zinc nanoparticles can be considered as a suitable candidate for use against bacterial contamination. Considering the toxic effect of silver nanoparticles on normal human skin cells, this issue should be seriously considered during the process of disinfecting objects, in terms of preserving the health and safety of conservators and visitors.

Fungi play a significant role in the deterioration of cultural heritage. Due to their high enzyme activity, fungi are able to inhabit and destroy the various materials used for historical objects. Because of the cellulose structure of the paper, paper works in archival documents are very vulnerable to damage by microorganisms, including fungi, and they are always faced with the problem of biodeterioration. Considering the harmful effects of using chemicals on paper works as well as their toxic effect on museum curators and conservators in museum collections and libraries, it is very necessary to find a suitable alternative to deal with destructive fungi. In this regard, the use of herbal essential oils has always been considered. Considering the diversity and abundance of medicinal plants in our country, Iran, in this study, the antifungal effect of the essential oils of three plants including Thymus, Lavender, and Boswellia was evaluated against two common fungal strains isolated from historical documents, including Penicillium and Aspergillus niger. Also, the possible physical and chemical effects of these essential oils on paper were studied to determine which essential oil can be the most suitable option for the decontamination of paper documents.The results obtained in this study confirm that the three investigated essential oils have antifungal activity. But based on the dose required for antimicrobial activity, it can be said that thymus essential oil has more antifungal activity than lavender and Boswellia essential oil. Due to the thymus’s high antimicrobial effect and also the absence of adverse effects on pH and physical properties on paper, it can be a suitable and promising option for protecting paper documents against fungal biodeterioration.

Biodeterioration of library materials is a worldwide problem in archives and libraries. Investigation of biological agents (quantitatively and qualitatively) as well as environmental factors that affect the survival and persistence of microorganisms, are the main parts of preventive conservation. Therefore, we studied the biological pollution in repositories and other parts of the Documentation Center and Library of the Cultural Heritage and Tourism Research Institute and evaluated the environmental factors (temperature, relative humidity) in order to preserve paper works.

Method and Research Design: 

Quantitative and qualitative investigations of biological contaminants (bacteria and fungi) were performed using sedimentation method (passive method). In addition, environmental factors (temperature and relative humidity) were monitored in audiovisual and records repositories.

Relative humidity and temperature variation rates were high and non-standard in the audiovisual and records repositories. Biological studies showed that the fungal and bacterial contamination level in the library repository was higher than the alert level. The most frequent bacterial isolates were Bacillus and Staphylococcus and the dominant fungal isolates belonged to the genera Aspergillus, Penicillium, Alternaria, Cladosporium, most of which have a high potential to produce decomposing enzymes.

Green synthesis of nanoparticles (NPs) is a simple, fast, and eco-friendly method which could be performed by various microorganisms or plant extracts. Silver NPs are well-known as antimicrobial and anti-fungal materials. They play an essential role in the control of tumors via their cytotoxic effects. Therefore, they have attracted significant attention for developing an effective treatment solution for cancer cells. This study aimed to investigate the potential of Penicillium chrysogenum for the synthesis of silver NPs and to evaluate their toxicity on liver cancer cell line (HepG2).

After synthesis of NPs using P. chrysogenum, characterization of the synthesized NPs was performed by UV–Vis spectroscopy, X-ray diffraction (XRD), and transmission electron microscopy (TEM). Fourier transform infrared spectroscopy (FTIR) was carried out to detect biomolecules that may be responsible for the synthesis and stabilization of NPs. The cytotoxic activity of the synthesized AgclNPs on HepG2 cell line was evaluated using MTT assay.

UV–Vis spectroscopy and XRD analysis confirmed the synthesis of AgclNPs using P. chrysogenum. TEM analysis revealed the spherical shape of AgclNPs with an average crystalline size of 15 to 45 nm. FTIR spectroscopy indicated the possible functional groups that could be responsible for the reduction of metal ions and the capping process. These nanoparticles showed a dose-dependent anticancer activity against HepG2 cells.

The results suggest that biosynthesized silver chloride nanoparticles could offer potential applications in cancer therapy.

Biological contamination of paper artifacts is a significant threat, causing not only damage to the paper itself but also posing health risks to conservators and restorers who are in close contact with them. Therefore, identifying the type of contamination is crucial for effective preservation and restoration. This article focuses on identifying biological contamination in a collection of paper artifacts from the Imamzadeh Mohammad in Tafresh, Iran. Preliminary examinations revealed evidence of biological contamination, including stains resulting from biological activity. These stains are a consequence of biodeterioration, leading to a reduction in the structural and artistic quality of the artifacts. To investigate the biological contamination, samples were taken from areas suspected of contamination and cultured on Sabouraud dextrose agar (for fungal contamination) and nutrient agar (for bacterial contamination). After incubation, the grown colonies were examined and identified. The results of the identification of isolated fungal and bacterial showed contamination with various fungi, including Penicillium, Aspergillus, Cladosporium, and yeasts, as well as bacteria belonging to the Actinomycetes and Bacillus genus.

Cultural heritage has always been the focus of many civilizations and therefore, it needs to be preserved for future generations. From prehistoric times, when grandeur and beauty were the aims of architecture, stone was the most widely used durable material. Biodeterioration of the stone monuments, one of the most important causes for the loss of the cultural heritage, is defined as any undesirable change in the properties of a material caused by the action of biological agents such as fungi, bacteria, cyanobacteria, lichens and plants, as well as animals such as insects. The world heritage of Persepolis, for example, has been unprotected from biodeterioration for the centuries, and has unfortunately not been addressed during this time. The purpose of this study is to provide a new perspective on the study of the destructive biological factors affecting this historic site to provide a framework for future studies and serious consideration of the biological debate in conservation and restoration issues. Therefore, the presence of various factors possibly derived from the action of animals, vascular plants, mosses, fungi, lichens, green microalgae, and photosynthetic and non-photosynthetic bacteria were investigated. Based on objective observations, the presence of biodegradation factors affecting floors and the all sides of walls of various buildings in Persepolis was qualitatively investigated. Based on the results, the studied areas were classified into four classes with very high, high, medium and low risk. In addition to the initial estimate of biodiversity, the factors affecting the biodegradation of Persepolis were presented for the first time and the critical points for the presence of destructive factors were determined. Lichens exist throughout Persepolis and have proved useful in archaeological studies, since their growth can be chronologically employed to measure the age of rocks and indeed ancient monuments, their radial growth increasing logarithmically over time based on the assumed specific rate. In this study, the presence of lichens has been investigated from the perspective of biodeterioration, their presence at the microscopic scale can intensify the weathering and biodeterioration of the rock. Such action is not visible to the naked eye but leaves irreparable damage to the stone surface. It was estimated that this complex process at Persepolis is the result of more than 15 different Vascular plant species and 5 Non-vascular plant (mosses), 16 or 17 different species of birds, 3 to 5 species of snails and 2 to 4 species of reptiles and insects. It was shown that the establishment of a biomonitoring laboratory at Persepolis is the important task of studying the action of microorganisms since it is estimated that more than 20 strains of non-photosynthetic bacteria, more than 10 taxa of cyanobacteria, about 15 plants and mosses, more than 130 lichen species and 20 species of non-lichen fungi are involved in the biodegradation of Persepolis. The results are the estimative and provide the basis for more detailed studies to monitor the factors involved in biodegradation, which is one of the necessities of this World Heritage Site.

This study was done to determine the level of high level gentamicin resistant (HLGR) and vancomycin resistant enterococci (VRE) in the healthy normal human population living in Tehran, Iran. A total of 700 fecal samples were isolated from the period of September 2007 to September 2008 and the species were identified by the biochemical tests and PCR. Antibiotic susceptibility test, gentamicin and vancomycin resistant genes and the conjugation tests were performed to evaluate the transferability of the drug resistant genes. The clonality of the isolates was also determined by PFGE. The results showed that the prevalence of HLGR and VRE in the healthy normal population were 16.6% (100) and 1% (6) for HLGR and VRE, respectively. Amongst the HLGR enterococci, the most frequent species were found to be Enterococcus faecalis in 63% of the isolates. This was followed by E. faecium (33%), E. gallinarum (3%) and E. casseliflavus (1%). The frequency of the gentamicin resistant genes were 99 (99%), 91 (91%), 3(3%) and 1(1%) for aac(6')-Ie-aph(2'')-Ia, aph(3')-IIIa, ant(4')Ia and aph(2'')-Id genes, respectively. Among the vancomycin resistant genes, vanA was found in 1% (6) of isolates only. PFGE revealed high heterogeneity among the 63 E. faecalis strains and 33 E. faecium with 31 and 28 different patterns, respectively. The 6 VR E. faecium revealed 6 different patterns. The prevalence and heterogenous populations of HLGR in the normal flora of the humans found here were higher than reports from many countries, may be suggestive of excessive antibiotic usage in Iranian.

Lactic acid bacteria, especially Lactobacillus spp., have been considered as excellent probiotic microorganisms, because of their activities in reducing the enteric diseases and maintaining healthy poultry.. The current study aimed to evaluate the phenotypic characteristics and the probiotic potentials of Lactobacillus spp. isolated from poultry.. A total of 168 lactic acid bacteria (LAB) were isolated from healthy six and twenty-one-day old chickens and their feed samples. The isolated bacteria were identified by morphological, biochemical, and molecular tests including Polymerase Chain Reaction (PCR) and 16S rRNA gene sequencing. Biochemical fingerprinting with Phene Plate system (Ph-P) was done and the acid and bile resistant lactobacilli were subjected to the antibiotic susceptibility test.. Amongst all of the examined LAB, 30.3% were resistant to bile and acid. Most of the isolated LAB (57.1%) belonged to the genus Lactobacillus with Lactobacillus brevis (78.1%) as the dominant species followed by L. reuteri (16.6%), L. plantarum (3%), and L. vaginalis (2%). The remaining isolates were identified as Pediococcus spp. (42.9%). The Ph-P cluster analysis of 75 L. brevis and 16 L. reuteri strains showed high phenotypic diversity. Whilst the results of Ph-P typing from L. reuteri strains showed low phenotypic variations especially among the strains sensitive to acid and bile salts.. Overall, the results showed that some of the high potential probiotic LAB species existed in Iranian poultry..