Frontiers in Biology

ISSN 1674-7984

ISSN 1674-7992(Online)

CN 11-5892/Q

   Online First

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, Volume 6 Issue 5

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REVIEW
MicroRNAs and drug modulation in cancer: an intertwined new story
Francesca FANINI, Ivan VANNINI, Muller FABBRI
Front Biol. 2011, 6 (5): 351-356.  
https://doi.org/10.1007/s11515-011-1115-9

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MicroRNAs (miRNAs) are endogenous small non-coding RNAs (ncRNAs) which play important regulatory roles in physiological processes such as cellular differentiation, proliferation, development, apoptosis and stem cell self-renewal. An increasing number of papers have clearly claimed their involvement in cancer, providing, in some cases, also the molecular mechanisms implicated. Several studies led to the conclusion that miRNAs can be effectively used as anticancer agents alone or in combination with existing anticancer drugs. In particular, miRNAs can be effectively used to overcome drug resistance, one of the main factors responsible for anticancer treatment insuccess. One of the main questions remains how to modulate the expression of miRNAs in cancer cells. Interestingly, a few studies have shown that the expression of miRNAs is affected by drugs (including some drugs currently used as anticancer agents), therefore providing the rationale for an intertwined scenario in which miRNAs can be modulated by drugs and, in turn, can affect drug sensitivity of cancer cells.

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Enterococcus: review of its physiology, pathogenesis, diseases and the challenges it poses for clinical microbiology
John VU, John CARVALHO
Front Biol. 2011, 6 (5): 357-366.  
https://doi.org/10.1007/s11515-011-1167-x

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The genus Enterococcus is composed of 38 species, the most important of which are Enterococcus faecalis and Enterococcus faecium—both human intestinal colonizers. Hospitals within the United States and around the world commonly isolate these bacteria because they are a cause of bacteremia, urinary tract infections (UTIs), endocarditis, wound infections, meningitis, intraabdominal and pelvic infections, and nosocomial and iatrogenic infections. Given the ubiquity of enterococci within the human population, it is important for laboratories to be able to distinguish these agents within hospitalized patients from other bacterial genera and also differentiate different species within the Enterococcus genus as well as different strains within each species. Unfortunately, the enterococci are emerging as serious pathogens in both the developed world, where surveillance needs to be improved and speciation procedures are inadequate or cumbersome, and in developing nations, which lack the trained hospital personnel or funding to sufficiently identify enterococci to the genus or species level. This review explores the Enterococcus genus and highlights some of the concerns for national and international clinical microbiology laboratories.

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New glimpses of caveolin-1 functions in embryonic development and human diseases
Saijun MO, Shengli YANG, Zongbin CUI
Front Biol. 2011, 6 (5): 367-376.  
https://doi.org/10.1007/s11515-011-1132-8

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Caveolin-1 (Cav-1) isoforms, including Cav-1α and Cav-1β, were identified as integral membrane proteins and the major components of caveolae. Cav-1 proteins are highly conserved during evolution from BoldItalic to human and are capable of interacting with many signaling molecules through their caveolin scaffolding domains to regulate the activities of multiple signaling pathways. Thus, Cav-1 plays crucial roles in the regulation of cellular proliferation, differentiation and apoptosis in a cell-specific and contextual manner. In addition, Cav-1 is essential for embryonic development of vertebrates owing to its regulation of BMP, Wnt, TGF-β and other key signaling molecules. Moreover, Cav-1 is mainly expressed in terminally differentiated cells and its abnormal expression is often associated with human diseases, such as tumor progression, cardiovascular diseases, fibrosis, lung regeneration, and diseases related to virus. In this review, we will further discuss the potential of Cav-1 as a target for disease therapy and multiple drug resistance.

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The trafficking and behavior of cellulose synthase and a glimpse of potential cellulose synthesis regulators
Logan BASHLINE, Juan DU, Ying GU
Front Biol. 2011, 6 (5): 377-383.  
https://doi.org/10.1007/s11515-011-1161-3

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Cellulose biosynthesis is a topic of intensive research not only due to the significance of cellulose in the integrity of plant cell walls, but also due to the potential of using cellulose, a natural carbon source, in the production of biofuels. Characterization of the composition, regulation, and trafficking of cellulose synthase complexes (CSCs) is critical to an understanding of cellulose biosynthesis as well as the characterization of additional proteins that contribute to the production of cellulose either through direct interactions with CSCs or through indirect mechanisms. In this review, a highlight of a few proteins that appear to affect cellulose biosynthesis, which includes: KORRIGAN (KOR), Cellulose Synthase-Interactive Protein 1 (CSI1), and the poplar microtubule-associated protein, PttMAP20, will accompany a description of cellulose synthase (CESA) behavior and a discussion of CESA trafficking compartments that might act in the regulation of cellulose biosynthesis.

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Advances in plant cell type-specific genome-wide studies of gene expression
Ying WANG, Yuling JIAO
Front Biol. 2011, 6 (5): 384-389.  
https://doi.org/10.1007/s11515-011-1141-7

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Cell is the functional unit of life. To study the complex interactions of systems of biological molecules, it is crucial to dissect these molecules at the cell level. In recent years, major progresses have been made by plant biologists to profile gene expression in specific cell types at the genome-wide level. Approaches based on the isolation of cells, polysomes or nuclei have been developed and successfully used for studying the cell types from distinct organs of several plant species. These cell-level data sets revealed previously unrecognized cellular properties, such as cell-specific gene expression modules and hormone response centers, and should serve as essential resources for functional genomic analyses. Newly developed technologies are more affordable to many laboratories and should help to provide new insights at the cellular resolution in the near future.

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Roles of histone ubiquitylation in DNA damage signaling
Sui-Sui DONG, Michael S. Y. HUEN
Front Biol. 2011, 6 (5): 390-397.  
https://doi.org/10.1007/s11515-011-1135-5

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Histone ubiquitylation has emerged as an important chromatin modification associated with DNA damage signaling and repair pathways. These histone marks, laid down by E3 ubiquitin ligases that include RNF8 and RNF168, decorate chromatin domains surrounding DNA double-strand breaks (DSBs). Recent work implicated ubiquitylated histones in orchestrating cell cycle checkpoints, DNA repair and gene transcription. Here we summarize recent advances that contribute to our current knowledge of the highly dynamic nature of DSB-associated histone ubiquitylation, and discuss major challenges ahead in understanding the versatility of ubiquitin conjugation in maintaining genome stability.

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Evolution of the chloroplast division machinery
Hongbo GAO, Fuli GAO
Front Biol. 2011, 6 (5): 398-413.  
https://doi.org/10.1007/s11515-011-1139-1

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Chloroplasts are photosynthetic organelles derived from endosymbiotic cyanobacteria during evolution. Dramatic changes occurred during the process of the formation and evolution of chloroplasts, including the large-scale gene transfer from chloroplast to nucleus. However, there are still many essential characters remaining. For the chloroplast division machinery, FtsZ proteins, Ftn2, SulA and part of the division site positioning system— MinD and MinE are still conserved. New or at least partially new proteins, such as FtsZ family proteins FtsZ1 and ARC3, ARC6H, ARC5, PDV1/PDV2 and MCD1, were introduced for the division of chloroplasts during evolution. Some bacterial cell division proteins, such as FtsA, MreB, Ftn6, FtsW and FtsI, probably lost their function or were gradually lost. Thus, the chloroplast division machinery is a dynamically evolving structure with both conservation and innovation.

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RESEARCH ARTICLE
Drosophila highwire gene modulates acute ethanol sensitivity in the nervous system
Awoyemi A. AWOFALA
Front Biol. 2011, 6 (5): 414-421.  
https://doi.org/10.1007/s11515-011-1144-4

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Animals exhibit behavioral differences in their sensitivity to ethanol, a trait that is at least in part due to genetic predispositions. This study has implicated a large neuronal protein involving Highwire, a Drosophila E3 ubiquitin ligase (Hiw, a homolog of Pam, a protein associated with Myc found in humans) in acute sensitivity to ethanol sedation. Flies lacking Hiw were hypersensitive to the sedating effect of ethanol whereas those overexpressing Hiw showed decreased sensitivity to ethanol. Furthermore, RNAi functional knockdown of Hiw in adult neurons or ellipsoid body neurons showed increased sensitivity to ethanol sedation. None of these manipulations of the hiw gene caused changes in the rate of ethanol absorption and/or metabolism. These results suggest a previously unknown role for this highly conserved gene in regulating the behavioral responses to an addictive drug.

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Mitochondrial DNA sequence diversity in three ethnic populations from the South-west Iran: a preliminary study
Elham DAVOUDI-DEHAGHANI, Ali Mohammad FOROUGHMAND, Babak SAFFARI, Massoud HOUSHMAND, Hamid GALEHDARI, Mehdi SHAFA SHARIAT PANAHI, Majid YAVARIAN, Mohammad Hossein SANATI, Somayeh TORFI
Front Biol. 2011, 6 (5): 422-432.  
https://doi.org/10.1007/s11515-011-1140-8

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To investigate the genetic structure of human populations in the South-west region of Iran, mitochondrial first hypervariable DNA sequences were obtained from 50 individuals representing three different ethnic groups from Khuzestan Province. Studied groups were Shushtari Persians and Chahar Lang Bakhtiyaries from Indo-European-speaking populations and Bani Torof Arabs from Semitic-speaking linguistic families. Genetic analysis of mtDNA data showed high similarity of Chahar Lang Bakhtiyaries with other Iranian Indo-European-speaking populations while Shushtaries and Bani Torofs had a closer affinity with Semitic-speaking groups rather than to other Iranian populations. The relationship of Chahar Lang Bakhtiyaries and Bani Torof Arabs with their neighbor populations can be explained by linguistic and geographic proximity. Whereas, the greater similarity of Shushtari Persians with West Asian Arabs is probably according to high gene flow between them. This article represents a preliminary study of three major ethnic groups of South-west Iran which investigates the potential genetic substructure of the region.

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ERRATUM
10 articles