Tendency For Differentiation Research Articles

SALL4 and C-kit positive malignant extrarenal rhabdoid tumor of the pelvis in a child: A diagnostic and therapeutic challenge

ABSTRACT Extrarenal rhabdoid tumors (ERRTs) are highly aggressive pediatric tumors with very few cases reported in the literature. These tumors, similar to their renal counterparts, are characterized by inactivating mutations of the SMARCB1/INI-1 gene, a member of the SWI/SNF chromatin remodeling pathway. Diagnosis of ERRTs appears challenging owing to its rarity, varied morphological profile with a higher tendency for rhabdoid differentiation, and overlapping features with other SMARCB-1 deficient tumors. Here, we report a case of ERRT in the pelvis of a three-year-old child with an unusual expression of SALL4 and C-kit on immunohistochemistry. A complete immunohistochemical workup might help in differentiating ERRTs from other SMARCB1/INI1-deficient soft tissue tumors. The expression of stem cell markers in the presented case also suggests that these tumors might originate from or share similarities with embryonic stem cells or germ cells.

Recent Advances in the Classification of Bladder Cancer - Updates from the 5th Edition of the World Health Organization Classification of the Urinary and Male Genital Tumors.

The World Health Organization Classification (WHO) of Urinary and Male Genital Tumors has recently been updated to its 5th edition. The new edition presents a comprehensive approach to the classification of urinary and male genital tumors with an incorporation of morphologic, clinical, and genomic data. This review aims to update the new classification of bladder cancer in the 5th edition and to highlight important changes in nomenclatures, diagnostic criteria, and molecular characterization, as compared to the 4th edition. The pathologic classification of bladder cancer in the 5th edition of WHO Classification of Urinary and Male Genital Tumours was compared to that in the 4th edition. PubMed was searched using key words, including bladder cancer, WHO 1973, WHO 1998, WHO 2004, WHO 2016, histology, pathology, genomics, and molecular classification in the time frame from 1973 to August of 2022. Other relevant papers were also consulted, resulting in the selection of 81 papers as references. The binary grading of papillary urothelial carcinoma (UC) is practical, but it may be oversimplified and contribute to "grade migration" in recent years. An arbitrary cutoff (5%) has been proposed for bladder cancers with mixed grades. The diagnosis of papillary urothelial neoplasm with low malignant potential has been dramatically reduced in recent years because of overlapping morphology and treatment with low-grade papillary UC. An inverted growth pattern should be distinguished from true (or destructive) stromal invasion in papillary UC. Several methods have been proposed for pT1 tumor substaging, but it is often challenging to substage pT1 tumors in small biopsy specimens. Bladder UC shows a high tendency for divergent differentiation, leading to several distinct histologic subtypes associated with an aggressive clinical behavior. Molecular classification based on the genomic analysis may be a useful tool in the stratification of patients for optimal treatment. The 5th edition of WHO Classification of Urinary and Male Genital Tumours has made several significant changes in the classification of bladder cancer. It is important to be aware of these changes and to incorporate them into routine clinical practice.

Basal Cell Carcinomas After Radiotherapy Show More Frequent Follicular Differentiation Than Tumors From Sun-Exposed Areas: Immunohistochemical Study With a Special Focus on Infundibulocystic Basal Cell Carcinoma.

Patients submitted to radiotherapy for tinea capitis in childhood have an increased incidence of scalp basal cell carcinomas (BCCs) but also of other neoplasms, namely, follicular tumors. In a cohort of such patients, we also found a high incidence of infundibulocystic BCCs, an otherwise rare variant. We thus hypothesized that postradiotherapy BCCs could be more prone to display follicular differentiation. We compared the histological and immunohistochemical features of postradiotherapy BCCs [both conventional (16 cases) and infundibulocystic (16 cases)] with those of BCCs arising in sun-exposed areas (16 cases), using markers of follicular differentiation (PHLDA-1, CK15, CD34, β-catenin, and calretinin). Postradiotherapy BCCs showed slightly higher tendency for infundibular and/or trichilemmal differentiation than BCCs from sun-exposed areas (37.5% vs. 18.8%), but this difference was not statistically significant. Nevertheless, infundibulocystic BCCs showed more frequent expression of PHLDA-1 and stronger cytoplasmic expression of CK15 compared with the other lesions. In addition, CD34 highlighted a characteristic meshwork of stromal cells surrounding the epithelial component in all infundibulocystic BCCs, in contrast to the other postradiotherapy BCCs and UV-related BCCs, in which 78.1% were negative or only focally positive. In conclusion, our study suggests a tendency for more frequent follicular differentiation in postradiotherapy BCCs compared with BCCs from sun-exposed areas. In addition, the immunohistochemical study confirms previous data from the literature regarding infundibulocystic BCCs (higher CK15 and PHLDA-1 expression) and shows a distinctive stromal positivity for CD34 that has not been previously acknowledged in these tumors.

Mucosal Microbiota and Metabolome in the Ileum of Hu Sheep Offered a Low-Grain, Pelleted or Non-pelleted High-Grain Diet.

Alterations in mucosal microbiota and metabolites are critical to intestinal homeostasis and host health. This study used a combination of 16S rRNA gene sequencing and liquid chromatography-mass spectrometry (LC/MS) to investigate mucosal microbiota and their metabolic profiles in the ileum of Hu sheep fed different diets. Here, we randomly allocated 15 Hu sheep to three diets, a non-pelleted low-grain diet (control diet; CON), a non-pelleted high-grain diet (HG), and a pelleted high-grain diet (HP). After 60 days of treatment, ileal mucosal samples were collected for microbiome and metabolome analysis. The results of principal coordinate analysis and permutation multivariate analysis showed that there was a tendency for microbial differentiation between the CON and HG groups (P < 0.1), although no significant difference between the HG and HP groups was observed (P > 0.05). Compared with the CON diet, the HG diet decreased (P < 0.05) the abundance of some probiotic species (e.g., Sphingomonas and Candidatus Arthromitus) and increased (P < 0.05) the abundance of acid-producing microbiota (e.g., Succiniclasticum, Nesterenkonia, and Alloprevotella) in the ileal mucosa. Compared with the HG diet, the HP diet decreased (P < 0.05) the abundance of Alloprevotella and increased (P < 0.05) the abundance of Mycoplasma in the ileal mucosa. Furthermore, partial least squares discriminant analysis and orthogonal partial least-squared discriminant analysis indicated that different dietary treatments resulted in different metabolic patterns in the ileal mucosa of the CON, HG, and HP groups. The HG diet altered (VIP > 1 and P < 0.05) the metabolic patterns of amino acids, fatty acids, and nucleotides/nucleosides (such as increased amounts of ornithine, tyrosine, cis-9-palmitoleic acid, and adenosine) compared with the CON diet. However, 10 differential metabolites (VIP > 1 and P < 0.05; including tyrosine, ornithine, and cis-9-palmitoleic acid) identified in the HG group exhibited a diametrically opposite trend in the HP group, suggesting that the HP diet could partially eliminate the changes brought upon by the HG diet. Collectively, our findings demonstrate that different diets altered the ileal mucosal microbiota and metabolites and provide new insight into the effects of high-grain diets on the intestinal health of ruminant animals.

Cystatin-B Negatively Regulates the Malignant Characteristics of Oral Squamous Cell Carcinoma Possibly Via the Epithelium Proliferation/Differentiation Program.

Disturbance in the proteolytic process is one of the malignant signs of tumors. Proteolysis is highly orchestrated by cysteine cathepsin and its inhibitors. Cystatin-B (CSTB) is a general cysteine cathepsin inhibitor that prevents cysteine cathepsin from leaking from lysosomes and causing inappropriate proteolysis. Our study found that CSTB was downregulated in both oral squamous cell carcinoma (OSCC) tissues and cells compared with normal controls. Immunohistochemical analysis showed that CSTB was mainly distributed in the epithelial structure of OSCC tissues, and its expression intensity was related to the grade classification. A correlation analysis between CSTB and clinical prognosis was performed using gene expression data and clinical information acquired from The Cancer Genome Atlas (TCGA) database. Patients with lower expression levels of CSTB had shorter disease-free survival times and poorer clinicopathological features (e.g., lymph node metastases, perineural invasion, low degree of differentiation, and advanced tumor stage). OSCC cell models overexpressing CSTB were constructed to assess the effects of CSTB on malignant biological behaviors and upregulation of CSTB inhibited cell proliferation, migration, and invasion in vitro. Weighted gene correlation network analysis (WGCNA) and gene set enrichment analysis (GSEA) were performed based on the TCGA data to explore potential mechanisms, and CSTB appeared to correlate with squamous epithelial proliferation-differentiation processes, such as epidermal cell differentiation and keratinization. Moreover, in WGCNA, the gene module most associated with CSTB expression (i.e., the brown module) was also the one most associated with grade classification. Upregulation of CSTB promoted the expression levels of markers (LOR, IVL, KRT5/14, and KRT1/10), reflecting a tendency for differentiation and keratinization in vitro. Gene expression profile data of the overexpressed CSTB cell line were obtained by RNA sequencing (RNA-seq) technology. By comparing the GSEA enrichment results of RNA-seq data (from the OSCC models overexpressing CSTB) and existing public database data, three gene sets (i.e., apical junction, G2/M checkpoint, etc.) and six pathways (e.g., NOTCH signaling pathway, glycosaminoglycan degradation, mismatch repair, etc.) were enriched in the data from both sources. Overall, our study shows that CSTB is downregulated in OSCC and might regulate the malignant characteristics of OSCC via the epithelial proliferation/differentiation program.

An in vitro analysis of the effect of hyperosmolarity on the chondrogenic potential of human articular cartilage derived chondroprogenitors

PurposeChondroprogenitors display promise for articular cartilage regeneration. It is imperative to standardize culture conditions, to further enhance chondrogenicity and reduce tendency for hypertrophy. Cartilage matrix provides a unique hyperosmolar microenvironment that enables native cells to resist compressive stress. However, commonly used culture media have osmolarities relatively hypoosmotic when compared to in-vivo conditions. Previous reports involving chondrocytes demonstrated enhanced chondrogenic potential secondary to utilization of hyperosmolar culture conditions. The study aimed to assess the effect of hyperosmolarity (either mimicking normal joint conditions or short-term hyperosmotic stress) on chondroprogenitor phenotype. Materials and methodsFibronectin adhesion assay derived human articular chondroprogenitors (n = 3) were divided into 3 groups: a) Control: cells grown in standard culture conditions (320 mOsm/L), b) Test A: cells grown in hyperosmolar media mimicking joint conditions (409 mOsm/L) and c) Test B: cells exposed to short-term hyperosmotic stress (504 mOsm/L) for 24 h, prior to assessment. Evaluation parameters included population doubling, cell size, surface marker expression, mRNA expression (markers of chondrogenesis, dedifferentiation and hypertrophy) and multilineage potential. ResultsSubjecting these cells to increased osmolarity in culture did not demonstrably favor chondrogenesis (control vs Test A: comparable COL2A1) while hyperosmotic stress further increased the tendency for hypertrophy and terminal differentiation (high COL1A1 and low COL2A1, P = 0.006). Additionally, growth kinetics, surface marker expression and multilineage potential were comparable across groups. ConclusionChondroprogenitors displayed sensitivity to increase in osmolarity as chondrogenic phenotype did not improve, while hypertrophic propensity was heightened, although further analysis of culture and phenotypic parameters will aid in optimizing chondroprogenitor use in cartilage regeneration.

Increased SOX2 expression in three-dimensional sphere culture of dental pulp stem cells

Mesenchymal stem cells in the dental pulp exhibit a tendency for differentiation into various dental lineages and hold great potential as a major conduit for regenerative treatment in dentistry. Although they can be readily isolated from teeth, the exact characteristics of these stem cells have not been fully understood so far. When compared to twodimensional (2D) cultures, three-dimensional (3D) cultures have the advantage of enriching the stem cell population. Hence, 3D-organoid culture and 3D-sphere culture were applied to dental pulp cells in the current study. Although the establishment of the organoid culture proved unsuccessful, the 3D-sphere culture readily initiated the stable generation of cell aggregates, which continued to grow and could be passaged to the second round. Interestingly, a significant increase in SOX2 expression was detected in the 3D-spheroid culture compared to the 2D culture. These results indicate the enrichment of the stemness-high population in the 3D-sphere culture. Thus, 3D-sphere culture may act as a link between the conventional and 3D-organoid cultures and aid in understanding the characteristics of dental pulp stem cells.

Inflammation and hematopoietic stem cells aging.

Hematopoietic stem cells (HSCs) replenish all lineages of blood cells throughout the lifespan. During aging, the repopulation capacity of HSCs declined, and aged HSCs display a tendency for myeloid differentiation. Several intrinsic and extrinsic factors have been identified to promote HSCs aging. In this review, we focus on the contribution of aging-associated inflammation in provoking HSCs aging and discuss the future research direction of inflammation and HSC aging.

Anterior cruciate ligament remnant cells have different potentials for cell differentiation based on their location

Histological and cytological observations of the human anterior cruciate ligament (ACL) had been described, but the differentiation potency based on their location is still unknown. To determine and compare proliferation and differentiation potential of cells derived from distal and middle thirds of the ACL remnant, ACL remnant was initially marked at the distal third (within 10 mm from the tibial insertion) and middle third (between 10–20 mm from the tibial insertion) and then dissected. Both the middle and distal third regions of ACL remnant were analyzed using CD34+ cell counting. Cell proliferation rate did not differ in both middle and distal third regions of ACL remnant, but they showed different characteristics in cell differentiation depending on their location. The distal third region of the ACL remnant had a tendency for chondrogenic differentiation with higher expression of CD34+ cells. On the other hand, the middle third region of ACL remnant had a strong tendency for osteogenic and ligamentous differentiation. Characteristics of the ACL remnant tissues should be considered when performing remnant-preserving or harvesting ACL remnants for tissue engineering.

WNT Inhibition and Increased FGF Signaling Promotes Derivation of Less Heterogeneous Primed Human Embryonic Stem Cells, Compatible with Differentiation.

Human embryonic stem cells (hESCs) hold great value for future clinical applications. However, standard culture conditions maintain hESCs in a primed state, which bears heterogeneity in pluripotency and a tendency for spontaneous differentiation. To counter these drawbacks, primed hESCs have been converted to a naive state, but this has restricted the efficiency of existing directed differentiation protocols. In mouse, WNT inhibition by inhibitor of WNT production-2, together with a higher dose of fibroblast growth factor 2 (12 ng/mL) in DMEM/F12 basal medium (DhiFI), markedly improved derivation and maintenance of primed mouse epiblast stem cells. In this study, we show that DhiFI conditions similarly improved primed hESC traits, such as conferring a primed transcriptional signature with high levels of pluripotency markers and reduced levels of differentiation markers. When triggered to differentiate to neuronal and cardiac lineages, DhiFI hESCs and isogenic primed hESCs progressed similarly. Moreover, DhiFI conditions supported the derivation of hESC lines from a post-inner cell mass intermediate (PICMI). DhiFI-derived hESCs showed less spontaneous differentiation and expressed significantly lower levels of lineage-specific markers, compared to primed-derived lines from the same PICMI. Overall, DhiFI hESCs retained advantages of both primed and naive pluripotency and may ultimately represent a more favorable starting point for differentiation toward clinically desired cell types.

Secretome proteins regulate comparative osteogenic and adipogenic potential in bone marrow and dental stem cells

IntroductionDental stem cells (DMSC) have been studied extensively since their early discovery. However, the data regarding osteogenic potential of DMSC with other cell types is sparse and the secretome proteins underlying these differences have not been explored. In this study, we have compared the osteogenic and adipogenic potential of DMSC with Bone Marrow Stem cells (BMSC) and reported the contribution of secretome proteins in controlling their differentiation. MethodsOsteogenic potential of these stem cells was compared by mineralization assay, alkaline phosphatase (ALP) assay, immunofluorescence of dentine sialo phosphoprotein (DSPP) & qPCR for osteogenic genes. Adipogenic potential was compared by Oil Red O staining and qPCR for PPAR-γ, leptin & adipsin. Proteomic analysis of secretome was performed by employing WATERS nano Lc-MS/MS system. ResultsWe observed a higher osteogenic potential in DMSC, especially dental pulp stem cells (DPSC) as compared to BMSC population but adipogenic potential was found to be better in BMSC as compared to DMSC. Deeper investigations into secretome of these cells by Lc-MS/MS revealed the presence of proteins pertaining to osteogenic and adipogenic lineage. Presence of some important proteins regulating osteogenic (DSPP, BMP7, DDR2, USP9X) and adipogenic differentiation (NCOA2, PEG10, LPA) in secretome of BMSC and DMSC reflected the role of paracrine factors during differentiation. ConclusionOur study provides first evidence regarding regulation of osteogenic/adipogenic potential by secretome proteins in DMSC and BMSC. DMSC especially DPSC and its secretome show an inherent tendency for higher osteogenic differentiation and lower adipogenic differentiation, these may be potential candidates for effective future therapy in osteoporosis where disturbance of osteocyte/adipocyte homeostasis is reported.

Effect of avulsion storage media on periodontal ligament fibroblast differentiation.

An avulsed tooth must be stored in a solution which maintains periodontal ligament (PDL) cell viability. The aim of this study was to compare the effects of Hank's balanced salt solution (HBSS) and milk on the differentiation of PDL fibroblasts. Eighteen extracted third molars, (n=3 for each group), were immersed in HBSS, milk, and Dulbecco's modified Eagle medium-Ham's F12 (DMEM-F12) at 4°C for 30- to 60 minutes or 12hours. The growth dynamics of PDL fibroblasts were evaluated with cell proliferation graphics and population doubling time (PDT) values. Runt-related transcription factor 2 (RUNX2), receptor activator of nuclear factor kappa-B ligand (RANKL), and collagen type XII (COL12) expression were used to evaluate the differentiation of PDL fibroblasts. The percentage of cell numbers and PDT values of groups were statistically insignificant. In the HBSS groups, RUNX2 expression increased showing a direction to osteogenic differentiation of PDL fibroblasts. In the DMEM-F12 groups, RANKL expression increased, indicating there was a tendency for osteoclastogenic differentiation. In the milk groups, RUNX2 expression decreased while other markers were stable showing PDL fibroblasts could protect fibroblast identity. In terms of protecting fibroblast identity and resistance to differentiation, milk was more effective than HBSS.

Post-transcriptional regulation of gene expression in neural stem cells.

Expression of each gene can be controlled at several steps during the flow of genetic information from DNA to protein. Tight regulation of gene expression is especially important for stem cells because of their greater ripple effects, compared with terminally differentiated cells. Dysregulation of gene expression arising in stem cells can be perpetuated within the stem cell pool via self-renewal throughout life. In addition, transcript profiles within stem cells can determine the selective advantage or disadvantage of each cell, leading to changes in cell fate, such as a tendency for proliferation, death, and differentiation. The identification of neural stem/progenitor cells (NSPCs) and greater understanding of their cellular physiology have raised the possibility of using NSPCs to replace damaged or injured neurons. However, an accurate grasp of gene expression control must take precedence in order to use NSPCs in therapies for neurological diseases. Recently, accumulating evidence has demonstrated the importance of post-transcriptional regulation in NSPC fate decisions. In this review, we will summarize and discuss the recent findings on key mRNA modulators and their vital roles in NSPC homeostasis. Copyright © 2016 John Wiley & Sons, Ltd.

MiR-221 attenuates the osteogenic differentiation of human annulus fibrosus cells

BackgroundIn the moderate and end stages of intervertebral disc (IVD) degeneration, endochondral ossifications are found in the IVD. PurposeThe aim of this study was to investigate whether endochondral ossification in the late stages of disc degeneration is due to the differentiation of resident progenitor cell in the annulus fibrosus (AF) and the potential signaling pathways in vitro. Study DesignThis is an in vitro study of AF cell osteogenic differentiation and possible mechanisms MethodsNormal annulus fibrosus (NAF) and degenerated annulus fibrosus (DAF) cells were isolated from tissue removed surgically from juvenile patients with idiopathic scoliosis and adult patients with degenerative scoliosis. Osteogenic differentiation was investigated using quantitative reverse transcription polymerase chain reaction (RT-PCR) and histology. The effects of miR-221 on osteogenesis were measured by overexpression of miR-221 with lentivirus. BMP2 and phospho-Smad proteins were detected by Western blotting. ResultsBoth NAF and DAF cells underwent osteogenic differentiation, which was confirmed by detecting mineralization of the cell cultures and by an increase in the expression mRNAs for BMP2, runx2, alkaline phosphatase (ALP), and osteocalcin. DAF cells exhibited increased osteogenic differentiation potential over the NAF cells. By contrast to the elevated phospho-Smads, the basal level of miR-221 significantly decreased in DAF cells compared with that in NAF cells. Cultures of both cell types in osteogenic medium showed a decrease in miR-221 expression, and overexpression of miR-221 markedly decreased the level of BMP2, phospho-Smads, and the expression of osteogenic genes in DAF cells. The osteogenic potential of DAF cells diminished by the overexpression of miR-221. ConclusionCompared with NAF cells, AF cells from degenerated discs have a greater tendency for osteogenic differentiation, which involves the BMP-Smad pathways and can be regulated by miR-221. These observations may be developed into a therapeutic to prevent the endochondral ossification.

Dental follicle stem cells in bone regeneration on titanium implants.

BackgroundWe aimed to demonstrate that DF stem cells from impacted molars and canines can be used to improve bone regeneration on titanium implants surfaces. This study highlights the presence of stem cells in DF, their potential to adhere and differentiate into osteoblasts on different types of titanium surfaces.ResultsIsolated cells from the harvested DF tissue from impacted canine/molars, expressed stem cells markers. Differentiation into bone cells was induced in presence or absence of BMP-2 and TGFβ1. The presence of growth factors until 28 days in medium maintained the cells in an earlier stage of differentiation with a lower level of specific bone proteins and a higher expression of alkaline phosphatase (ALP). Influence of titanium implants with different bioactive coatings, hydroxyapatite (TiHA) and with silicatitanate (TiSiO2), and porous Ti6Al7Nb implants as control (TiCtrl), was studied in terms of cell adhesion and viability. Ti HA implants proved to be more favorable for adhesion and proliferation of DF stem cells in first days of cultivation. The influence of titanium coatings and osteogenic differentiation mediums with or without growth factors were evaluated. Additional BMP-2 in the medium did not allow DF stem cells to develop a more mature phenotype, leaving them in a pre-osteogenic stage. The best sustained mineralization process evaluated by immuno-cytochemical staining, scanning electron microscopy and Ca2+ quantification was observed for TiHA implants with a higher expression of ALP, collagen and Ca2+ deposition. Long term culturing (70 days) on titanium surfaces of DF stem cells in standard medium without soluble osteogenic inducers, indicated that HA coating is more favorable, with the acquisition of a more mature osteoblastic phenotype as shown by immunocytochemical staining. These findings demonstrated that even in absence of exogenous osteogenic factors, TiHA implants and in a lesser extent TiCtrl and TiSiO2 implants can induce and sustain osteogenic differentiation of DF stem cells, by their chemical and topographical properties.ConclusionsOur research demonstrated that DF stem cells have a spontaneous tendency for osteogenic differentiation and can be used for improving bone regeneration on titanium implants surfaces.Electronic supplementary materialThe online version of this article (doi:10.1186/s12896-015-0229-6) contains supplementary material, which is available to authorized users.

TAF4b is required for mouse spermatogonial stem cell development.

Long-term mammalian spermatogenesis requires proper development of spermatogonial stem cells (SSCs) that replenish the testis with germ cell progenitors during adult life. TAF4b is a gonadal-enriched component of the general transcription factor complex, TFIID, which is required for the maintenance of spermatogenesis in the mouse. Successful germ cell transplantation assays into adult TAF4b-deficient host testes suggested that TAF4b performs an essential germ cell autonomous function in SSC establishment and/or maintenance. To elucidate the SSC function of TAF4b, we characterized the initial gonocyte pool and rounds of spermatogenic differentiation in the context of the Taf4b-deficient mouse testis. Here, we demonstrate a significant reduction in the late embryonic gonocyte pool and a deficient expansion of this pool soon after birth. Resulting from this reduction of germ cell progenitors is a developmental delay in meiosis initiation, as compared to age-matched controls. While GFRα1+ spermatogonia are appropriately present as Asingle and Apaired in wild-type testes, TAF4b-deficient testes display an increased proportion of long and clustered chains of GFRα1+ cells. In the absence of TAF4b, seminiferous tubules in the adult testis either lack germ cells altogether or are found to have missing generations of spermatogenic progenitor cells. Together these data indicate that TAF4b-deficient spermatogenic progenitor cells display a tendency for differentiation at the expense of self-renewal and a renewing pool of SSCs fail to establish during the critical window of SSC development.

Trait distribution patterns in savanna and forest plant assemblages and their relationship with soil features

Community ecologists seek to understand the processes acting on community assembly and the importance of species ecological differences to the co-existence of organisms. Here we investigated trait distribution patterns in two contrasting vegetation types, how the inclusion of intraspecific variability improves our ability to understand trait-based assembly, and if soil features predict the occurrence of non-random trait distribution patterns. We conducted our study at Emas National Park, Goias, Brazil. We used a null model approach to investigate trait distribution patterns and a model selection approach to quantify soil features important in structuring assemblages. In savanna, we detected trait convergence at individual and species level (evidence of environmental filters) favoring plants with resource conservation strategies. In forests, however, trait dispersion at individual level equal to a random expectation corroborated a premise of neutral theory (individuals ecological equivalence). Nevertheless, at species level, we found convergence (seed mass) and divergence (height), reflecting distinct strategies related to light capture and resource use. Therefore, including intraspecific trait variability did not improve the detection of non-random trait distribution patterns. Furthermore, the influence of soil features on trait patterns was different between savanna and forest. There was a tendency for niche differentiation toward more fertile and clayey soils, but the relative importance of soil factors in assembling communities could not be generalized for savannas and dry forests.

Clustered airline flight scheduling: Evidence from airline deregulation in Korea

This paper explores the impacts of competition level on airline scheduling in the Korean domestic short-haul routes where a hub-and-spoke system is not the optimal air transport network strategy. The empirical findings using the Korean airline panel data for the period 2006–2010 suggest that competition leads to less differentiated departure flight times as expected from spatial competition theory. Unlike the previous study on the U.S airline industry, the degree of this tendency for less differentiation differs across the type of routes: the Jeju island routes (leisure type) and the inland routes (business type), in the deregulated period. Following the May 2008 Deregulation Act we find an increasingly clustered pattern of airline scheduling in the Jeju island routes where there have been competitive pressures associated with new low cost entrants. This recent evidence would imply that airline carriers strategically schedule departure flight times and allocate flights between routes as competition increases in the deregulated period.

“DO YOU SOUND ASIAN WHEN YOU SPEAK English?” RACIAL IDENTIFICATION AND VOICE IN CHINESE AND KOREAN Americans' ENGLISH

In paired dialect identification tasks, differing only by speakers' sex, New Yorkers were asked to identify the race and national heritage of other New Yorkers. Each task included eight speakers: two Chinese Americans, two Korean Americans, two European Americans, a Latino, and an African American. Listeners were successful at above chance rates at identifying speakers' races, but not at differentiating the Chinese from Koreans. Acoustic analyses identified breathier voice as a factor separating the Asian Americans most frequently identified from the non-Asians and Asians least successfully identified. Also, the Chinese and Latino men's speech appeared more syllable timed than the others' speech. Finally, longer voice onset times for voiceless stops and lower /ε/s and /r/s were also to be implicated in making a speaker “sound Asian.” These results support extending the study of the robust U.S. tendency for linguistic differentiation by race to Asian Americans, although this differentiation does not rise to the level of a systematic racial dialect. Instead, it is suggested that it be characterized as an ethnolinguistic repertoire along the lines suggested by Sarah Bunin Benor.

Down-regulation of achaete-scute complex homolog 1 (ASCL1) in neuroblastoma cells induces up-regulation of insulin-like growth factor 2 (IGF2)

Neuroblastoma (NB) is the most common extra-cranial solid pediatric tumor. The prognosis of patients with NB has been improved during the last decades. However, treatment results for patients with advanced tumor stages are still unsatisfying. NB cells are characterized by a high tendency for spontaneous or induced differentiation. During differentiation, down-regulation of the basic helix-loop-helix transcription factor achaete-scute complex homolog 1 (ASCL1) has been observed but the consequences of ASCL1 down-regulation have not been elucidated. We used RNA interference to knock-down ASCL1 in NB cells. DNA microarray analysis was used for the identification of ASCL1-regulated genes. Furthermore, conventional and quantitative reverse transcription-polymerase chain reaction (RT-PCR) was used for validation of ASCL1-regulated genes. Down-regulation of ASCL1 influenced the expression of several genes. After down-regulation of ASCL1, we observed very high expression of insulin-like growth factor 2 (IGF2), a factor that is known to be induced during differentiation of NB cells. RT-PCR indicated up-regulation of multiple IGF2 transcript variants after ASCL1 knock-down. Our data suggest that the ASCL1-pathway is responsible for the up-regulation of IGF2 during NB differentiation.