Biocompatibility evaluation of bacterial cellulose as a scaffold material for tissue-engineered corneal stroma

In this work, biocompatibility of bacterial cellulose (BC) was assessed as the scaffold for corneal stroma replacement. Biocompatibility was evaluated by examining rabbit corneal epithelial and stromal cells cultured on the BC scaffold. The growth of primary cells was assessed by optical microscope, scanning electron microscope (SEM), and transmission electron microscope (TEM). Live/dead viability/cytotoxicity assay and CCK-8 assay were used to evaluate cell survival. BC was surgically implanted in vivo into a stromal pocket. During a 3-month follow-up, the biocompatibility of BC was assessed. We found that epithelial and stromal cells grew well on BC and showed a survival rate of nearly 100\\%. The SEM examination for both kinds of cell showed abundant leafy protrusions, spherical projections, filopodia, cytoskeletons, and cellular interconnections. The stromal cells cultured on BC arranged regularly. TEM observation revealed normal cellular microstructure and a tight adhesion to the BC membrane. In vivo observation confirmed the optical transparency of BC during 3-month follow-up. The results demonstrated that BC had good biocompatibility for the tissue engineering of corneal stroma.This work is supported by the National Natural Science Foundation of China (Grant Nos. 81200663, 51572187, 51973058, and 31870963), Tianjin Clinical Key Discipline Project (Grant No. TJLCZDXKM014), and Key Research and Development Program of Jiangxi Province (No. 20192ACB80008, 20171BBG70112).info:eu-repo/semantics/publishedVersio

Incorporating graphene oxide into biomimetic nano-microfibrous cellulose scaffolds for enhanced breast cancer cell behavior

Electronic supplementary material The online version of this article (https://doi.org/10.1007/s10570-020-03078-w) contains supplementary material, which is available to authorized users.The impact of graphene oxide (GO) on normal cells has been widely investigated. However, much less is known on its effect on cancer cells. Herein, GO nanosheets were incorporated into electrospun cellulose acetate (CA) microfibers. The GO-incorporated CA (GO/CA) microfibers were combined with bacterial cellulose (BC) nanofibers via in situ biosynthesis to obtain the nano-microfibrous scaffolds. The GO/CA-BC scaffolds were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). The GO/CA-BC scaffolds were used for breast cancer cell culture to evaluate the effect of GO on cancer cell behavior. Fluorescence images revealed large multicellular clusters on the surface of GO/CA-BC scaffolds. Compared to the bare CA-BC scaffold, the GO/CA-BC scaffolds not only showed enhanced mechanical properties but also improved cell proliferation. It is expected that the GO/CA-BC scaffolds would provide a suitable microenvironment for the culture of cancer cells which is necessary for drug screening and cell biology study.This work was supported by National Natural Science Foundation of China (Grant nos. 51572187, 51973058, 31660264, 31870963), the Key Research and Development Program of Jiangxi Province (No. 20192ACB80008), and the Youth Science Foundation of Jiangxi Province (No. 20181BAB216010), and Key Project of Natural Science Foundation of Jiangxi Province (No. 20161ACB20018).info:eu-repo/semantics/publishedVersio

Cyclic axial compressive performance of hybrid double-skin tubular square columns

This paper presents an experimental study on the cyclic axial compressive behavior of FRP-concrete-steel hybrid double-skin tubular columns. The square column specimens were cast with an external Fiber Reinforced Polymer jackets, inner steel tube and concrete in between. The height of the columns was 500 mm and the side dimension was 150 mm. The effects of loading scheme, void ratio and diameter-thickness ratio on axial compression behavior were investigated. A total of eight columns were tested under monotonic and cyclic axial compression. The experimental results show that the effect of loading scheme on axial stress-strain envelope curve and the peak load were not significant, and the ultimate state of the square columns subjected to cyclic axial compression was very similar to that of specimens subjected to monotonic axial compression. Besides, compared with void ratio, the diameter-thickness ratio of the inner steel tube has significant influence on the peak load of the columns when subjected to cyclic axial compression

Penaeid shrimp genome provides insights into benthic adaptation and frequent molting

Crustacea, the subphylum of Arthropoda which dominates the aquatic environment, is of major importance in ecology and fisheries. Here we report the genome sequence of the Pacific white shrimp Litopenaeus vannamei, covering similar to 1.66 Gb (scaffold N50 605.56 Kb) with 25,596 protein-coding genes and a high proportion of simple sequence repeats (>23.93%). The expansion of genes related to vision and locomotion is probably central to its benthic adaptation. Frequent molting of the shrimp may be explained by an intensified ecdysone signal pathway through gene expansion and positive selection. As an important aquaculture organism, L. vannamei has been subjected to high selection pressure during the past 30 years of breeding, and this has had a considerable impact on its genome. Decoding the L. vannamei genome not only provides an insight into the genetic underpinnings of specific biological processes, but also provides valuable information for enhancing crustacean aquaculture

Sex-Based Differences in Age-Related Changes of the Vertebral Column from a Bronze Age Urban Population in Ancient China

The health disparities between males and females in bioarchaeological settings are important indicators of gender-based differences in socioeconomic roles. In this study, sex-based differences of the vertebral column in spine pathology were investigated in human skeletons excavated from a Bronze Age cemetery of the Western Zhou Dynasty at the Dahekou site in Shanxi, China. Results demonstrated that females had a higher prevalence of vertebral compressive fractures, with the majority found in those between twenty-five and thirty years old, suggesting that the fractures were a consequence of osteoporosis and its early onset in females. In contrast, males expressed overall more severe ageing in all vertebral divisions compared to females. Males also had a higher prevalence of vertebral facet joint osteoarthritis in cervical and thoracic divisions than females. Likewise, the incidence of facet joint osteoarthritis was more asymmetric between the left and right joints in males than in females. These findings reflect disparities of vertebral health between the two sexes in an urban setting, in which ageing and injuries of the vertebral column might be driven by different mechanisms. Age-related changes in female vertebral columns may have been more influenced by conditions of hormone deficiency such as menopause, while male vertebral columns might have been more prone to age-related changes due to heavy labor-induced physical stressors. Further studies on the differentiation of ageing mechanisms between the two sexes based on physiology, socioeconomic roles, and living conditions are warranted. The studies are necessary in understanding how multiple sociocultural and physiological factors contribute to health disparities in historic and contemporary environments

Evidence that a West-East admixed population lived in the Tarim Basin as early as the early Bronze Age

<p>Abstract</p> <p>Background</p> <p>The Tarim Basin, located on the ancient Silk Road, played a very important role in the history of human migration and cultural communications between the West and the East. However, both the exact period at which the relevant events occurred and the origins of the people in the area remain very obscure. In this paper, we present data from the analyses of both Y chromosomal and mitochondrial DNA (mtDNA) derived from human remains excavated from the Xiaohe cemetery, the oldest archeological site with human remains discovered in the Tarim Basin thus far.</p> <p>Results</p> <p>Mitochondrial DNA analysis showed that the Xiaohe people carried both the East Eurasian haplogroup (C) and the West Eurasian haplogroups (H and K), whereas Y chromosomal DNA analysis revealed only the West Eurasian haplogroup R1a1a in the male individuals.</p> <p>Conclusion</p> <p>Our results demonstrated that the Xiaohe people were an admixture from populations originating from both the West and the East, implying that the Tarim Basin had been occupied by an admixed population since the early Bronze Age. To our knowledge, this is the earliest genetic evidence of an admixed population settled in the Tarim Basin.</p

A Novel Candidate Gene Associated With Body Weight in the Pacific White Shrimp Litopenaeus vannamei

Improvements of growth traits are always the focus in selective breeding programs for the Pacific white shrimp Litopenaeus vannamei (L. vannamei). Identification of growth-related genes or markers can contribute to the application of modern breeding technologies, and thus accelerate the genetic improvement of growth traits. The aim of this study was to identify the genes and molecular markers associated with the growth traits of L. vannamei. A population of 200 individuals was genotyped using 2b-RAD techniques for genome-wide linkage disequilibrium (LD) analysis and genome-wide association study (GWAS). The results showed that the LD decayed fast in the studied population, which suggest that it is feasible to fine map the growth-related genes with GWAS in L. vannamei. One gene designated as LvSRC, encoding the class C scavenger receptor (SRC), was identified as a growth-related candidate gene by GWAS. Further targeted sequencing of the candidate gene in another population of 322 shrimps revealed that several non-synonymous mutations within LvSRC were significantly associated with the body weight (P &lt; 0.01), and the most significant marker (SRC_24) located in the candidate gene could explain 13% of phenotypic variance. The current results provide not only molecular markers for genetic improvement in L. vannamei, but also new insights for understanding the growth regulation mechanism in penaeid shrimp