Simulation of Scenarios of a Deep Population Crisis in a Rapidly Growing Population

Abstract-This article focuses on the modeling of crisis and threshold development of the population process during the formation of a new population in a competitive environment. As a population spreads, a deep population crisis may arise as a result an abrupt triggering of biotic countermeasures before resources for a further increase in population size are exhausted. A bottleneck occurred in the history of many populations, including humans at the time of the Neolithic crash in Europe. Invaders with high reproductive potential often exert deleterious effects on biosystems. The emergence of efficient competition can not only cause classical cyclical fluctuations, but also lead to a complete extinction of the population after a series of high peaks in its abundance. Two alternative scenarios provide classical examples of induced population crises. One was observed in Gause's experiments where an introduction of a predatory ciliate drove another ciliate species to extinction. The other scenario was observed in a series of experiments where bacteriophages were introduced into colonies of actively dividing bacteria that had a dynamically adapting antiviral mechanism. In this work, modifications to the model were proposed to describe the actual scenarios of crisis effects in population dynamics. Equations with deviating arguments in the time variable allowed a threshold effect of conditions on reproduction of the invasive species and an aggregated nature of the lagging regulation with two time factors. The computational scenarios described both completion of the process after a repeated outbreak and successful elimination of the population crisis via rapid adaptation. Deep crisis phenomena are characteristic of local population dynamics when organisms interact with viruses that are new to them.

CRISPR-Cas9, A Promising Therapeutic Tool for Cancer Therapy: A Review

Cancer is one of the most leading causes of mortality all over the world and remains a foremost social and economic burden. Mutations in the genome of individuals are taking place more frequently due to the excessive progress of xenobiotics and industrialization in the present world. With the progress in the field of molecular biology, it is possible to alter the genome and to observe the functional changes derived from genetic modulation using gene-editing technologies. Several therapies have been applied for the treatment of malignancy which affect the normal body cells; however, more effort is required to develop vsome latest therapeutic approaches for cancer biology and oncology exploiting these molecular biology advances. Recently, the Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) associated protein 9 (Cas9) system has emerged as a powerful technology for cancer therapy because of its great accuracy and efficiency. Genome editing technologies have demonstrated a plethora of benefits to the biological sciences. CRISPR- Cas9, a versatile gene editing tool, has become a robust strategy for making alterations to the genome of organisms and a potent weapon in the arsenal of tumor treatment. It has revealed an excellent clinical potential for cancer therapy by discovering novel targets and has provided the researchers with the perception about how tumors respond to drug therapy. Stern efforts are in progress to enhance its efficiency of sequence specific targeting and consequently repressing offtarget effects. CRISPR-Cas9 uses specific proteins to convalesce mutations at genetic level. In CRISPR-Cas9 system, RNA-guided Cas9 endonuclease harnesses gene mutation, DNA deletion or insertion, transcriptional activation or repression, multiplex targeting only by manipulating 20-nucleotide components of RNA. Originally, CRISPR-Cas9 system was used by bacteria for their defense against different bacteriophages, and recently this system is receiving noteworthy appreciation due to its emerging role in the treatment of genetic disorders and carcinogenesis. CRISPR-Cas9 can be employed to promptly engineer oncolytic viruses and immune cells for cancer therapeutic applications. More notably, it has the ability to precisely edit genes not only in model organisms but also in human being that permits its use in therapeutic analysis. It also plays a significant role in the development of complete genomic libraries for cancer patients. In this review, we have highlighted the involvement of CRISPR-Cas9 system in cancer therapy accompanied by its prospective applications in various types of malignancy and cancer biology. In addition, some other conspicuous functions of this unique system have also been discussed beyond genome editing.

The Klf6-related super enhancer regulates Klf6-SV2 expression mediated proliferation in human hepatoma (HepG2) cells

Background

The Klf6 gene, which belongs to Krüppel-like family of C2H2 zinc finger transcription factors, is greatly related to tumorigenesis via a high rate of somatic mutation in the carcinomas of prostate, liver, colon, stomach, lung, neck, pituitary, and nervous system: Furthermore, the pathways regulating the expressions of Klf6 splice variants termed Klf6-SV1, -SV2, and -SV3 remain obscure although their functional outcomes have been clear. In this study, the functional roles of Klf6 variants in the inhibition of cell proliferation induced by the disruption of Klf6-related super enhancer in human hepatoma (HepG2) cells were evaluated.

Results

As a result, the disruption of Klf6-related super enhancer not only induced the upregulation of Klf6-SV2 but also led to a significant reduction of proliferation in HepG2 cells. In addition, the disruption of Klf6-related super enhancer led to the induction of p21 and Bax genes mediated by the upregulation of Klf6-SV2.

Conclusion

In conclusion, it was demonstrated that Klf6-related super enhancer modulates cell proliferation via the regulation of Klf6-SV2 expression in human hepatoma (HepG2) cells. The results provide the functional significance of Klf6-related super enhancer in understanding the transcriptional regulation mechanism of Klf6.

CRISPR-mediated adaptive immune systems in bacteria and archaea

Effective clearance of an infection requires that the immune system rapidly detects and neutralizes invading parasites while strictly avoiding self-antigens that would result in autoimmunity. The cellular machinery and complex signaling pathways that coordinate an effective immune response have generally been considered properties of the eukaryotic immune system. However, a surprisingly sophisticated adaptive immune system that relies on small RNAs for sequence-specific targeting of foreign nucleic acids was recently discovered in bacteria and archaea. Molecular vaccination in prokaryotes is achieved by integrating short fragments of foreign nucleic acids into a repetitive locus in the host chromosome known as a CRISPR (clustered regularly interspaced short palindromic repeat). Here we review the mechanisms of CRISPR-mediated immunity and discuss the ecological and evolutionary implications of these adaptive defense systems.