Virulence Factors in Streptococcus pneumonia and the Role of Complement C1q in the Immune Response

المكورات العقدية الرئوية Streptococcus pneumonia  هي بكتيريا إيجابية الغرام , تستعمر في الأسطح المخاطية من البلعوم الأنفي تعتبر من مسببات الأمراض الرئيسية لدى البشر, من الأمراض التي تسببها هي الالتهاب الرئوي والتهاب السحايا. تنتج هذه البكتريا العديد من عوامل الضراوة التي تشارك في ميكانيكيه الإصابة, ان المعركة بين المضيف البشري والممرض الجرثومي معقدة للغاية  اذ يحاول كل طرف التفوق على الآخر من أجل البقاء.  الجهاز المناعي الذاتي في الأنسان وخاصة نظام المتمم  complement system يعتبر خط الدفاع الأول ضد مسببات الأمراض الغازية. بصورة عامة تمتلك الممرضات عدد من الاستراتيجيات لمواجهة نظام المتمم  من أجل البقاء والاستمرار داخل المضيف, وأحد هذه المُمْرِضات هو المكورات الرئوية Streptococcus pneumonia التي تمتلك العديد من عوامل الضراوة تساعدها في أحداث الإصابة داخل جسم المضيف, مثل قابلية المكورات الرئوية على الالتصاق adhesions , تكوين المستعمرات  colonize, التي تعتبر العوامل الأساسية في أحداث الإصابة. تناقش هذه المراجعة الفعاليات البيولوجية ضد عوامل الضراوة للمكورات الرئوية, وتوضح الدور الرئيسي لجزيئة المتمم الأولى (( C1q التي تنشط ضد الإصابة خلال المسلك الكلاسيكي للمتمم .  Streptococcus pneumonia is a major pathogen in humans, and causes diseases such as pneumonia and meningitis. This bacterium produces many virulence factors that participate in the mechanics of injury. The battle between human host and bacterial pathogen is extremely complex. Each side tries to outpace the other in the race for survival. Particularly in the innate immune system in humans, the complementary immune system acts as the first line of defense against invading pathogens during the course of evolution, however, the pathogen has developed multiple strategies to counter the host complement system and colonization, for survival and sustainability within the host. One of these pathogens is Streptococcus (pneumococcus), which are Gram-positive bacterial pathogens that often coexist in the human respiratory system. Depending on the host's sensitivity, pneumococcus can transform into an infectious agent that spreads within the human host and causes diseases ranging from mild to severe and potentially life-threatening diseases. This transition from the symbiont to the infectious agent is a very complex process and an understanding of this mechanism is essential in controlling pneumococcal disease. Using its complex arsenal of weapons such as surface adhesions as well as pneumococcal recruitment recruit the host's immune system. This review discusses the biological activity of several pneumococcal virulence agents and describes C1q, the first subunit of the classic complement pathway, and its role in antimicrobial reactions, as pneumococcus exploits C1q as a molecular bridge that facilitates the attachment of this bacterium to the cell surfaces of the host

Evaluation of Different Methods of Curing Bacterial Plasmids

تلعب البلازميدات دورا مهما في انتشار صفة مقاومة المضادات الحيوية بين السلالات البكترية والتي تشكل تهديدا  على الصحة العالمية. لذا اقتضت الضرورة ايجاد طرق ناجعة و كفيلة للحد من انتقال البلازميدات. تعتمد الطرق التقليدية لازالة البلازميد على تنمية السلالات البكترية في ظل ظروف غير ملائمة ، مثل ارتفاع درجة الحرارة أو إضافة عوامل أقحام تتداخل مع بنية تركيب الدنا اثناء تكرار البلازميد. هنالك أساليب أخرى تعتمد على ظاهرة عدم توافق البلازميد القائمة على مبدأ التنافس بين البلازميدات المتطابقة ولكنها تتطلب معرفة دقيقة بآلية تضاعف البلازميد المستهدف ، بالإضافة إلى المعالجة اللاحقة للبلازميد المسبب للتداخل . مع ظهور تقنية كريسبركاس9 التي هي محاكاة الدفاع البكتيري الطبيعي ضد المتسللين من البلازميد والعاثي، تم استثمار هذه التقنية لتكون اداه دقيقة لاستهداف اماكن متخصصة في الحمض النووي البلازميدي. في هذه المراجعة سنتناول اهم طرق الازالة والحذف للبلازميدات من الخلايا البكتيرية.Plasmids play an important role in the spread of antibiotic resistance among bacterial strains that pose a threat to global health. Traditional methods of curing plasmid rely on the development of bacterial strains under inappropriate conditions, such as high temperature or the addition of intruding agents that interfere with the structure of DNA synthesis during the replication of plasmids. Other methods rely on the phenomenon of plasmid compatibility based on the principle of competition between identical plasmids but require accurate knowledge of the mechanism of multiplying the target plasmid, in addition to the subsequent treatment of the interfering plasmid. With the advent of Crispras9, which simulates natural bacterial defense against plasmid and latex infiltrators, this technique has been used as an accurate tool for targeting places specializing in plasmid DNA. In this review, we will address the most important methods of removing and deleting plasmids from bacterial cells

Interacting Generalised Cosmic Chaplygin gas in Loop quantum cosmology: A singularity free universe

In this work we investigate the background dynamics when dark energy is coupled to dark matter with a suitable interaction in the universe described by Loop quantum cosmology. Dark energy in the form of Generalised Cosmic Chaplygin gas is considered. A suitable interaction between dark energy and dark matter is taken into account in order to at least alleviate (if not solve) the cosmic coincidence problem. The dynamical system of equations is solved numerically and a stable scaling solution is obtained. A significant attempt towards the solution of the cosmic coincidence problem is taken. The statefinder parameters are also calculated to classify the dark energy model. Graphs and phase diagrams are drawn to study the variations of these parameters. It is seen that the background dynamics of Generalised Cosmic Chaplygin gas is completely consistent with the notion of an accelerated expansion in the late universe. From the graphs, generalised cosmic Chaplygin gas is identified as a dark fluid with a lesser negative pressure compared to Modified Chaplygin gas, thus supporting a 'No Big Rip' cosmology. It has also been shown that in this model the universe follows the power law form of expansion around the critical point, which is consistent with the known results. Future singularities that may be formed in this model as an ultimate fate of the universe has been studied in detail. It was found that the model is completely free from any types of future singularities.Comment: 10 pages, 10 figures. arXiv admin note: text overlap with arXiv:1109.1481, arXiv:1102.275

Characterization of the S = 9 excited state in Fe8Br8 by Electron Paramagnetic Resonance

High Frequency electron paramagnetic resonance has been used to observe the magnetic dipole, $\Delta$ M$_s$ = $\pm$ 1, transitions in the $S = 9$ excited state of the single molecule magnet Fe$_8$Br$_8$. A Boltzmann analysis of the measured intensities locates it at 24 $\pm$ 2 K above the $S = 10$ ground state, while the line positions yield its magnetic parameters D = -0.27 K, E = $\pm$0.05 K, and B$_4^0$ = -1.3$\times$ 10$^{-6}$ K. D is thus smaller by 8% and E larger by 7% than for $S = 10$. The anisotropy barrier for $S = 9$ is estimated as 22 K,which is 25% smaller than that for $S = 10$ (29 K). These data also help assign the spin exchange constants(J's) and thus provide a basis for improved electronic structure calculations of Fe$_8$Br$_8$.Comment: 7 pages, Figs included in text, submitted to PR

Cosmic coincidence problem and variable constants of physics

The standard model of cosmology is investigated using time dependent cosmological constant $\Lambda$ and Newton's gravitational constant $G$. The total energy content is described by the modified Chaplygin gas equation of state. It is found that the time dependent constants coupled with the modified Chaplygin gas interpolate between the earlier matter to the later dark energy dominated phase of the universe. We also achieve a convergence of parameter $\omega\to-1$, with minute fluctuations, showing an evolving $\omega$. Thus our model fairly alleviates the cosmic coincidence problem which demands $\omega=-1$ at present time.Comment: 27 pages, 15 figure

Semiconductive and Photoconductive Properties of the Single Molecule Magnets Mn12_{12}-Acetate and Fe8_8Br8_8

Resistivity measurements are reported for single crystals of Mn$_{12}$-Acetate and Fe$_8$Br$_8$. Both materials exhibit a semiconductor-like, thermally activated behavior over the 200-300 K range. The activation energy, $E_a$, obtained for Mn$_{12}$-Acetate was 0.37 $\pm$ 0.05 eV, which is to be contrasted with the value of 0.55 eV deduced from the earlier reported absorption edge measurements and the range of 0.3-1 eV from intramolecular density of states calculations, assuming $2E_a$= $E_g$, the optical band gap. For Fe$_8$Br$_8$, $E_a$ was measured as 0.73 $\pm$ 0.1 eV, and is discussed in light of the available approximate band structure calculations. Some plausible pathways are indicated based on the crystal structures of both lattices. For Mn$_{12}$-Acetate, we also measured photoconductivity in the visible range; the conductivity increased by a factor of about eight on increasing the photon energy from 632.8 nm (red) to 488 nm (blue). X-ray irradiation increased the resistivity, but $E_a$ was insensitive to exposure.Comment: 7 pages, 8 figure

Interacting new generalized Chaplygin gas

We have presented a model in which the new generalized Chaplygin gas interacts with matter. We find that there exists a stable scaling solution at late times in the evolution of the universe. Moreover, the phantom crossing scenario is observed in this model.Comment: 16 pages, 6 figures, accepted for publication in Int. J. Theor. Phy

Dynamics of Modified Chaplygin Gas in Brane World Scenario: Phase Plane Analysis

In this work we investigate the background dynamics when dark energy is coupled to dark matter with a suitable interaction in the universe described by brane cosmology. Here DGP and the RSII brane models have been considered separately. Dark energy in the form of modified Chaplygin gas is considered. A suitable interaction between dark energy and dark matter is considered in order to at least alleviate (if not solve) the cosmic coincidence problem. The dynamical system of equations is solved numerically and a stable scaling solution is obtained. A significant attempt towards the solution of the cosmic coincidence problem is taken. The statefinder parameters are also calculated to classify the dark energy models. Graphs and phase diagrams are drawn to study the variations of these parameters. It is also seen that the background dynamics of modified Chaplygin gas is completely consistent with the notion of an accelerated expansion in the late universe. Finally, it has been shown that the universe in both the models follows the power law form of expansion around the critical point, which is consistent with the known results.Comment: 14 pages, 14 figure

Dynamics of Interacting Generalized Cosmic Chaplygin gas in Brane-world scenario

In this work we explore the background dynamics when dark energy is coupled to dark matter with a suitable interaction in the universe described by brane cosmology. Here DGP and the RSII brane models have been considered separately. Dark energy in the form of Generalized Cosmic Chaplygin gas is considered. A suitable interaction between dark energy and dark matter is considered in order to at least alleviate (if not solve) the cosmic coincidence problem. The dynamical system of equations is solved numerically and a stable scaling solution is obtained. A significant attempt towards the solution of the cosmic coincidence problem is taken. The statefinder parameters are also calculated to classify the dark energy models. Graphs and phase diagrams are drawn to study the variations of these parameters. It is also seen that the background dynamics of Generalized Cosmic Chaplygin gas is consistent with the late cosmic acceleration, but not without satisfying certain conditions. It has been shown that the universe in both the models follows the power law form of expansion around the critical point, which is consistent with the known results. Future singularities were studied and our models were declared totally free from any types of such singularities. Finally, some cosmographic parameters were also briefly studied. Our investigation led to the fact that although GCCG with a far lesser negative pressure compared to other DE models, can overcome the relatively weaker gravity of RS II brane, with the help of the negative brane tension, yet for the DGP brane model with much higher gravitation, the incompetency of GCCG is exposed, and it cannot produce the accelerating scenario until it reaches the phantom era.Comment: 34 pages, 30 figures. arXiv admin note: substantial text overlap with arXiv:1204.3531, arXiv:1109.1481, arXiv:1109.357

Risk of mortality among inpatients with COVID-19 and type 2 diabetes: national data from Kuwait

Introduction To investigate type 2 diabetes as a risk factor for COVID-19 death following hospital admission in Kuwait. Methods A retrospective cohort study using data from a central hospital that cared for all hospitalized COVID-19 patients in Kuwait. We investigated the association between type 2 diabetes, with COVID-19 mortality using multiply imputed logistic regression and calculated the population attributable fraction. Results A total of 5333 patients were admitted with COVID-19, of whom 244 died (4.6%). Diabetes prevalence was 24.8%, but 53.7% of those who died had diabetes. After adjusting for age, sex, ethnicity and other comorbidities, diabetes was associated with death (OR 1.70 [95% CI 1.23, 2.34]) and admission to the intensive care unit more than 3 days after initial admission (OR 1.78 [95% CI 1.17, 2.70]). Assuming causality, the population attributable fraction for type 2 diabetes in COVID-19 death was 19.6% (95% CI 10.8, 35.6). Conclusion Type 2 diabetes is a strong risk factor for COVID-19 death in the Middle East. Given the high prevalence of type 2 diabetes in the Middle East, as well as many Western countries, the public health implications are considerable