Cooperation between osteoblastic cells and endothelial cells enhances their phenotypic responses and improves osteoblast function

Osteogenesis requires close co-operation with angiogenesis to create vascularized bone tissue. In this study, an indirect co-culture model using osteoblasts (OBs), primary endothelial cells (ECs) and Matrigel interlayer was established to understand the impact of each cell type on the other. ECs synergistically enhanced osteoblastic gene expression by OBs, while OBs were capable of supporting tubule-like structures formed by ECs on Matrigel, enhancing mean tubule length from 146.5 ± 23.5 μm in ECs alone to 192 ± 28.6 μm in co-culture (p < 0.05). Similar improvements were noted in terms of tubule number. An applicability study of the co-culture model to bone tissue engineering, performed on a biopolymer fibrous membrane, showed substantially enhanced deposition of calcified nodules. These results demonstrate the efficacy of co-culture with ECs to improve osteogenesis for bone tissue engineering.     

Effects of cytokinin on photosynthetic gas exchange, chlorophyll fluorescence parameters, antioxidative system and carbohydrate accumulation in cucumber (Cucumis sativus L.) under low light

The effects of 6-benzylaminopurine (6-BA) on plant growth, net photosynthetic rate, relative chlorophyll content, soluble protein, carbohydrates contents and antioxidant systems of cucumber (Cucumis sativus L.) under low-light environment were investigated using two different cucumber cultivars. The results showed that the weak light resulted in the remarkable decrease in plant net photosynthetic rate, relative chlorophyll content, soluble protein and carbohydrates contents, but promoted the superoxide dismutase and guaiacol peroxidase activities. However, application of 6-BA alleviated the reduction of the correlative parameters and mediated the changes of antioxidant systems. The potential mechanisms may involve the following aspects: 6-BA clearly enhanced the plants’ tolerance to low light by increasing chlorophyll content, reducing the production of superoxide radical (O ₂ ^·? ), and enhancing the quenching of hydrogen peroxide (H₂O₂), consequently alleviating the injury of photosynthetic system, and further increasing the efficiency of CO₂ assimilation, producing more carbohydrates which can meet the growth need of cucumber. Meanwhile, the present study indicated that cucumber of Europe mini type (Chunqiuwang) was more tolerant to low light than HuaNan type (Huza No.3).     

Rubia austrozhejiangensis sp. nov. (Rubiaceae) from Zhejiang,China

Rubia austrozhejiangensis Z. P. Lei, Y. Y. Zhou & R. W. Wang, a new species of Rubiaceae from China, is described and illustrated. The new species is similar to R. ovatifolia Z. Ying Zhang and R. argyi (H. Lév. & Vaniot) H. Hara ex Lauener, but differs from the former in having stems and branches cylindrical, not quadrate‐angled, long‐ovate to ovate‐lanceolate leaf blades, many‐flowered inflorescence, and smaller mericarps, 3–4 mm in diameter. In R. ovatifolia, stems and branches are quadrate‐angled, leaf blades ovate, ovate‐cordate to rounded cordate, and the inflorescences are sparsely flowered. Compared to R. argyi, the new species has cylindrical, not quadrate‐angled stems and branches, leaf blades that are long‐ovate to ovate‐lanceolate, 3–5‐veined, and slightly reflexed corolla lobes. In R. argyi, stems and branches are quadrate‐angled or winged, the corolla lobes are spreading, and the mericarps are 5–7 mm in diameter.     

The growth of Korean immigrant entrepreneurship in Chicago

The growth of Korean immigrant entrepreneurship in Chicago is a product of three interacting factors: employment opportunities in the general labour market, resource mobilization, and business opportunity structures. Because of their language barrier and less transferable education and occupational skills in the American labour market, many Korean immigrants could not find white‐collar occupations for which they had been trained. Disadvantaged, but still strongly motivated for upward economic mobility in the United States, many of them became self‐employed business owners. Korean immigrants’ middle‐class backgrounds and their stable family structures and strong family ties helped them to realize their goal of business ownership. In addition, social networks based on kinship, friendship, church membership, and school ties provided prospective business owners with financial assistance, training, business advice, and information about business opportunities. The first business opportunities for Korean immigrants of Chicago opened in Korean ethnic markets and non‐ethnic minority markets almost simultaneously in the early 1970s. While the demand of Koreans for their cultural products created an economic niche for Korean‐oriented businesses, the export‐import trade linkage between South Korea and the United States has paved the way for the entrance of Korean businesses into minority areas. Because of different economic niches, the two types of Korean businesses developed independently. The interethnic succession of residence, which had occurred in the late 1960s and early 1970s also produced vacated business opportunities in Koreatown and black neighbourhoods, enabling Korean immigrants to enter these areas without great resistance from local businesses. After Korean immigrants had accumulated capital and experience in Korean ethnic markets and minority markets, they advanced into more capital‐intensive businesses like garment manufacturing. Korean immigrant professionals began to enter the Korean ethnic economy in the early 1980s when the foundation of the Korean ethnic economy was already established.     

Sequence characterization and computational analysis of the non-ribosomal peptide synthetases controlling biosynthesis of lipopeptides, fengycins and bacillomycin D, from Bacillus amyloliquefaciens Q-426

Lipopeptides secreted by bacteria attract interest because of their uses in biomedicine, biotechnology and food technology; however, harnessing their megasynthases (non-ribosomal peptide synthetases, NRPSs) has met with some difficulties in heterologous expression and crystallization. Here, we used similarity and phylogenetic analysis of NRPS sequences, including the fengycin and iturin family synthetases from Bacillus spp., and have developed a novel approach for delineating the length and boundaries of NRPS domains from Bacillus amyloliquefaciens strain Q-426. The sequences were further characterized (including specific residues and conserved motifs) that gave insight into the basis of the substrate specificity. Data from the prediction of the NRPS domains, obtained by the self-optimized prediction method with Alignment program, showed they are all structurally unstable, making it difficult to determine their crystal structures.     

TAp73 Protein Stability Is Controlled by Histone Deacetylase 1 via Regulation of Hsp90 Chaperone Function

Histone deacetylases (HDACs) play important roles in fundamental cellular processes, and HDAC inhibitors are emerging as promising cancer therapeutics. p73, a member of the p53 family, plays a critical role in tumor suppression and neural development. Interestingly, p73 produces two classes of proteins with opposing functions: the full-length TAp73 and the N-terminally truncated ΔNp73. In the current study, we sought to characterize the potential regulation of p73 by HDACs and found that histone deacetylase 1 (HDAC1) is a key regulator of TAp73 protein stability. Specifically, we showed that HDAC1 inhibition by HDAC inhibitors or by siRNA shortened the half-life of TAp73 protein and subsequently decreased TAp73 expression under normal and DNA damage-induced conditions. Mechanistically, we found that HDAC1 knockdown resulted in hyperacetylation and inactivation of heat shock protein 90, which disrupted the interaction between heat shock protein 90 and TAp73 and thus promoted the proteasomal degradation of TAp73. Functionally, we found that down-regulation of TAp73 was required for the enhanced cell migration mediated by HDAC1 knockdown. Together, we uncover a novel regulation of TAp73 protein stability by HDAC1-heat shock protein 90 chaperone complex, and our data suggest that TAp73 is a critical downstream mediator of HDAC1-regulated cell migration.     

Cell proliferation is promoted by compressive stress during early stage of chondrogenic differentiation of rat BMSCs

The presence of an appropriate number of viable cells is prerequisite for successive differentiation during chondrogenesis. Chondrogenic differentiation has been reported to be influenced by mechanical stimuli. This research aimed to study the effects of cyclic compressive stress on cell viability of rat bone marrow‐derived MSCs (BMSCs) during chondrogenesis as well as its underlying mechanisms. The results showed that dynamic compression increased cell quantity and viability remarkably in the early stage of chondrogenesis, during which the expression of Ihh, Cyclin D1, CDK4, and Col2α1 were enhanced significantly. Possible signal pathways implicated in the process were explored in our study. MEK/ERK and p38 MAPK were not found to function in this process while BMP signaling seemed to play an important role in the mechanotransduction during chondrogenic proliferation. In conclusion, dynamic compressive stress could enhance cell viability during chondrogenesis, which might be achieved by activating BMP signaling. J. Cell. Physiol. 228: 1935–1942, 2013. © 2013 Wiley Periodicals, Inc.     

The adhesion protein IgSF9b is coupled to neuroligin 2 via S-SCAM to promote inhibitory synapse development

Synaptic adhesion molecules regulate diverse aspects of synapse formation and maintenance. Many known synaptic adhesion molecules localize at excitatory synapses, whereas relatively little is known about inhibitory synaptic adhesion molecules. Here we report that IgSF9b is a novel, brain-specific, homophilic adhesion molecule that is strongly expressed in GABAergic interneurons. IgSF9b was preferentially localized at inhibitory synapses in cultured rat hippocampal and cortical interneurons and was required for the development of inhibitory synapses onto interneurons. IgSF9b formed a subsynaptic domain distinct from the GABA_A receptor– and gephyrin-containing domain, as indicated by super-resolution imaging. IgSF9b was linked to neuroligin 2, an inhibitory synaptic adhesion molecule coupled to gephyrin, via the multi-PDZ protein S-SCAM. IgSF9b and neuroligin 2 could reciprocally cluster each other. These results suggest a novel mode of inhibitory synaptic organization in which two subsynaptic domains, one containing IgSF9b for synaptic adhesion and the other containing gephyrin and GABA_A receptors for synaptic transmission, are interconnected through S-SCAM and neuroligin 2.