Hamid Tebyanian

Bio: Hamid Tebyanian is an academic researcher from Baqiyatallah University of Medical Sciences. The author has contributed to research in topics: Bone regeneration & Decellularization. The author has an hindex of 13, co-authored 53 publications receiving 619 citations. Previous affiliations of Hamid Tebyanian include Shahid Bahonar University of Kerman & Islamic Azad University.

Oral microbial biofilms: an update

Abstract: Human oral cavity (mouth) hosts a complex microbiome consisting of bacteria, archaea, protozoa, fungi and viruses. These bacteria are responsible for two common diseases of the human mouth including periodontal (gum) and dental caries (tooth decay). Dental caries is caused by plaques, which are a community of microorganisms in biofilm format. Genetic and peripheral factors lead to variations in the oral microbiome. It has known that, in commensalism and coexistence between microorganisms and the host, homeostasis in the oral microbiome is preserved. Nonetheless, under some conditions, a parasitic relationship dominates the existing situation and the rise of cariogenic microorganisms results in dental caries. Utilizing advanced molecular biology techniques, new cariogenic microorganisms species have been discovered. The oral microbiome of each person is quite distinct. Consequently, commonly taken measures for disease prevention cannot be exactly the same for other individuals. The chance for developing tooth decay in individuals is dependent on factors such as immune system and oral microbiome which itself is affected by the environmental and genetic determinants. Early detection of dental caries, assessment of risk factors and designing personalized measure let dentists control the disease and obtain desired results. It is necessary for a dentist to consider dental caries as a result of a biological process to be targeted than treating the consequences of decay cavities. In this research, we critically review the literature and discuss the role of microbial biofilms in dental caries.

Hexadecane-degradation by Teskumurella and Stenotrophomonas Strains Isolated From Hydrocarbon Contaminated Soils

Abstract: Background: Petroleum hydrocarbons are mix compounds and divided into four groups: Saturates, Aromatics, Resins and Asphalten. Among various phases of crude-oil, the alkanes with medium length chain are favorable substrates that rapidly degraded, although short-chain alkanes are very toxic and long-chain alkanes have low solubility in water that reduce its bioavailability and make resistant to biodegradation. Objectives: The main goal of this study is the isolation, molecular identification and degradation properties of hexadecane degrading bacteria from contaminated soils. Materials and Methods: In this research to isolate aliphatic degrading bacteria, sampling from hydrocarbon contaminated soil with of petroleum reservoirs regions, Tehran were performed. Alkane degrading bacteria were isolated by enrichment in Bushnel-Hass medium with hexadecane as sole source of carbon and energy. The isolated strains were identified by amplification of 16S rDNA gene and sequencing. Alkane hydroxylase gene (alk-B) was identified in all strains by PCR with specific primers. Results: Among 8 strains three strains with high growth rate on hexadecane selected for further study. These three selected strains identified as Stenotrophomonas maltophilia strain M2, S. maltophilia strain Q2 and Tsukamurella tyrosinosolvens strain Q3. In comparison to the other bacteria, these bacterial strains can degrade hexadecane 2 times more; with a high emulsification activity. Conclusions: The 2.5% concentration of hexadecane was the best concentration that supports the growth of these strains. Among these strain T. tyrosinosolvens strain Q3 was the best strain for biodegradation of hexadecane. Alk-B gene was identified in all strains.

Clonogenic Neoblasts Are Pluripotent Adult Stem Cells That Underlie Planarian Regeneration

Abstract: Pluripotent cells in the embryo can generate all cell types, but lineage-restricted cells are generally thought to replenish adult tissues. Planarians are flatworms and regenerate from tiny body fragments, a process requiring a population of proliferating cells (neoblasts). Whether regeneration is accomplished by pluripotent cells or by the collective activity of multiple lineage-restricted cell types is unknown. We used ionizing radiation and single-cell transplantation to identify neoblasts that can form large descendant-cell colonies in vivo. These clonogenic neoblasts (cNeoblasts) produce cells that differentiate into neuronal, intestinal, and other known postmitotic cell types and are distributed throughout the body. Single transplanted cNeoblasts restored regeneration in lethally irradiated hosts. We conclude that broadly distributed, adult pluripotent stem cells underlie the remarkable regenerative abilities of planarians.

Immobilization of Microbes for Bioremediation of Crude Oil Polluted Environments: A Mini Review.

Abstract: Petroleum hydrocarbons are the most common environmental pollutants in the world and oil spills pose a great hazard to terrestrial and marine ecosystems. Oil pollution may arise either accidentally or operationally whenever oil is produced, transported, stored and processed or used at sea or on land. Oil spills are a major menace to the environment as they severely damage the surrounding ecosystems. To improve the survival and retention of the bioremediation agents in the contaminated sites, bacterial cells must be immobilized. Immobilized cells are widely tested for a variety of applications. There are many types of support and immobilization techniques that can be selected based on the sort of application. In this review article, we have discussed the potential of immobilized microbial cells to degrade petroleum hydrocarbons. In some studies, enhanced degradation with immobilized cells as compared to free living bacterial cells for the treatment of oil contaminated areas have been shown. It was demonstrated that immobilized cell to be effective and is better, faster, and can be occurred for a longer period.

Emerging SARS-CoV-2 variants of concern and potential intervention approaches.

Abstract: The major variant of concerns (VOCs) have shared mutations in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike proteins, mostly on the S1 unit and resulted in higher transmissibility rate and affect viral virulence and clinical outcome. The spike protein mutations and other non-structural protein mutations in the VOCs may lead to escape approved vaccinations in certain extend. We will discuss these VOC mutations and discuss the need for combination therapeutic strategies targeting viral cycle and immune host responses.