Individuality and slow dynamics in bacterial growth homeostasis

Microbial growth and division are fundamental processes relevant to many areas of life science. Of particular interest are homeostasis mechanisms, which buffer growth and division from accumulating fluctuations over multiple cycles. These mechanisms operate within single cells, possibly extending over several division cycles. However, all experimental studies to date have relied on measurements pooled from many distinct cells. Here, we disentangle long-term measured traces of individual cells from one another, revealing subtle differences between temporal and pooled statistics. By analyzing correlations along up to hundreds of generations, we find that the parameter describing effective cell-size homeostasis strength varies significantly among cells. At the same time, we find an invariant cell size which acts as an attractor to all individual traces, albeit with different effective attractive forces. Despite the common attractor, each cell maintains a distinct average size over its finite lifetime with suppressed temporal fluctuations around it, and equilibration to the global average size is surprisingly slow (> 150 cell cycles). To demonstrate a possible source of variable homeostasis strength, we construct a mathematical model relying on intracellular interactions, which integrates measured properties of cell size with those of highly expressed proteins. Effective homeostasis strength is then influenced by interactions and by noise levels, and generally varies among cells. A predictable and measurable consequence of variable homeostasis strength appears as distinct oscillatory patterns in cell size and protein content over many generations. We discuss the implications of our results to understanding mechanisms controlling division in single cells and their characteristic timescalesComment: In press with PNAS. 50 pages, including supplementary informatio

Thermophilic bioremediation of emerging pollutants using a recombinant thermophilic fungal peroxidase

Please click Additional Files below to see the full abstract

The “Shiite issue” in Iraqi-Iranian relations under Saddam Hussein

The article analyzes the views of Saddam Hussein, based on his statements regarding the “Shiite question”, which was originally based on the ideological heritage of the Ba’th, set out in the Constitution of 1951. However, under the influence of the processes that took place in Iraq throughout the 1970s, in particular the Kurdish national movement and the “Islamic awakening” of Shiites under the influence of the Iranian Revolution of 1979, Saddam Hussein was forced to adjust the ideas of the Ba’th to new realities. As a result, Saddam was forced to recognize the multinational nature of Iraqi society and the rights of Shiites to worship, abandoning the Ba’th atheistic principles. The evolution of viewsthattook place, asthe war with Iran showed, contributedtothe consolidation of Iraqi society around the Ba’th program and the personality of Saddam Hussein

Changes in liver functions tests during pregnancy

Pregnancy is a normal physiological phenomenon associated with many physiological changes that assist the nurturing and survival of the fetus, liver function affected by these changes. A prospective study carried out to assess serum level of routine Liver Function Test (LFTs) which included Alb, T.S.B, S.ALT, S.AST, S.ALP and Prothrombin time in ninety pregnant women, thirty women in each trimester of pregnancy and thirty aged matched non pregnant women as a control group who attended to Al-Ramadi General Hospital for Maternity and Children. The results were as follows: S. Alb and T.S.B levels were significantly lower (P<0.001) during all three trimesters as compared to controls. S.ALP activity was significantly higher in third and second trimester (P<0.001) than in controls. SALT activity was significantly higher (P≤0.05) in third trimester than in controls. While serum AST activity and prothrombin time did not give significant differences between pregnant and non-pregnant wome

The role of Melatonin in reducing Obesity and its safety of use: A Review

Melatonin is the chiefly hormone formed via the pineal gland, its endogenous synthesis occur during the dark phase and controlled by the Suprachiasmatic Nucleus SCN, melatonin is a long-established and widely distributed chemical in nature that exhibits a variety of modes of action and functions in almost every living thing  regulating the circadian rhythms, sleep and wakefulness cycle, energy metabolism in addition to its ability to regulate the raleasing of many cytokines participate in weight plus appetite control . It has been established that the hormone is participated in the controlling of body weight, food intake, glucose metabolism and energy balance, the important role of melatonin in modifiable adipose tissue, lipid profile, inflammation and oxidative stress opens up great hopes for the treatment of obesity. Since obesity is a serious public health issue which results from the imbalance between the amount of calories eaten and the amount of energy expended and predisposes to various metabolic diseases, so this review has been focused on some physiological function of melatonin , its role in the controlling of energy equilibrium and reducing obesity in addition to the benefits of its supplementation

Cytotoxicity of Silver Nanoparticles Synthesized With the Assistant of Microwave

Silver nanoparticles (AgNPs) are broadly designed for various application. In the current research silver nanoparticles (AgNPs) have been examined for their poisonous outcome on human lymphocyte and chicken embryo fibroblast cell line. AgNPs were synthesized by a simple and easy method from AgNO3 solution with glucose exposed to microwave radiation. The typical size of AgNPs were 30 nm with spherical shape. The cells which cultured with diverse concentrations of silver were examined for their viability using MTT assess, a photometric technique to conclude cell metabolism. The results show that the cell viability of the both cell type were diminished significantly (P<0.05) in dosage dependent mode, and the silver nanoparticles presented higher cytotoxicity to CEF than to human lymphocyte at the same concentration and time point

Establishment of Brucellosis Relapse and Complications Registry: A Study Protocol

Brucellosis is an endemic bacterial zoonotic disease in developing countries; that is a serious public health problem in Iran. Brucellosis is a life-threatening multi-system disease in human with different clinical manifestations, complications and relapse. The incidence of brucellosis in Hamadan province, west of Iran is high. In addition, there is few reliable and population-based studies regarding relapse and complications of brucellosis in developing countries, therefore establishment of the registry system in areas with adequate occurrence of cases is needed to better understand the predictors of brucellosis relapse and complications and management of the disease. Detecting occurrence of relapse and complications over time and by geographical area provide information for further investigations and identification of health system deficiencies in the management of patients

Sensitivity of Vapor Cloud Explosion Exceedance Analysis to the Ignition Probability Model for Offshore Process Systems

Probabilistic methodologies have been strictly recommended in the offshore field since the worst offshore explosion disaster in terms of lives lost in the North Sea in 1988. For todays offshore projects, essential design specifications including design loads for critical hazardous events are produced by quantitative risk analysis (QRA), which substantially governs the success of offshore projects. The offshore topside process systems are most vulnerable to hydrocarbon-relevant disasters such as vapor cloud explosion (VCE) and fire. However, it still remains extremely challenging to properly predict and mitigate the risk of such complex offshore topside systems, due to the nature of complexity in the system in addition to harsh environmental and operating conditions. Therefore, this study aims to advance the understanding of uncertainties and risk in the complex offshore systems exposed to multiple interrelated natural and man-made hazards (i.e. winds, VCEs). This study investigates the effects of uncertainties on the risk quantification focusing on VCE risk and ignition probability models, which has not been studied yet. A detailed probabilistic risk quantification of VCE is performed for a specific offshore topside system. The estimated design explosion load based on the VCE risk is compared for different ignition probability models.Research reported in this paper was supported by an Early-Career Research Fellowship from the Gulf Research Program of the US National Academies of Sciences, Engineering, and Medicine. The content is solely the responsibility of the authors and does not necessarily represent the official views of the Gulf Research Program of the US National Academies of Sciences, Engineering, and Medicine