Allozyme variation in the diploid (A genome) populations ofScilla scilloides (Hyacinthaceae)

Allozyme variation at eleven loci encoding seven enzyme systems were examined in 20 populations of diploid (genome AA, 2n = 16)Scilla scilloides in China. In comparison with the average species of seed plants studied, populations of this species display a high amount of genetic variation (A = 2.0, P = 58.6%, H_o = 0.172, and H_e = 0.185). Allozyme variation pattern revealed predominant outcrossing within populations and considerable differentiation (F_ST = 0.314) among populations as well as between the subtropic and temperate regions. The wide distribution, long existence and outcrossing are presumably the main factors responsible for the high genetic diversity within populations. But the gravity dispersal of seeds and pollination by small insects set limits to the increase of genetic variation within populations and promote differentiation between populations and regions. In addition, allozyme variation does not distinguishS. scilloides var.albo-viridis and suggests that subtropic populations may be considered as a genetic entity.     

Effects of fertigation scheme on N uptake and N use efficiency in cotton

While fertigation can increase fertilizer use efficiency, there is an uncertainly as to whether the fertilizer should be introduced at the beginning of the irrigation or at the end, or introduced during irrigation. Our objective was to determine the effect of different fertigation schemes on nitrogen (N) uptake and N use efficiency (NUE) in cotton plants. A pot experiment was conducted under greenhouse conditions in year 2004 and 2005. According to the application timing of nitrogen (N) fertilizer solution and water (W) involved in an irrigation cycle, four nitrogen fertigation schemes [nitrogen applied at the beginning of the irrigation cycle (N–W), nitrogen applied at the end of the irrigation cycle (W–N), nitrogen applied in the middle of the irrigation cycle (W–N–W) and nitrogen applied throughout the irrigation cycle (N&W)] were employed in a completely randomized design with four replications. Cotton was grown in plastic containers with a volume of 84 l, which were filled with a clay loam soil and fertilized with 6.4 g of N per pot as unlabeled and ¹⁵N-labeled urea for 2004 and 2005, respectively. Plant total dry matter (DM) and N content in N–W was significantly higher than in N&W in both seasons, but these were not consistent for W–N and W–N–W treatments. In year 2005, a significantly higher nitrogen derived from fertilizer (NDFF) for the whole plant was found in W–N and N–W than that in W–N–W and N&W. Fertigation scheme had a consistent effect on total NUE: N–W had the highest NUE for the whole plant, but this was not significantly different from W–N. Treatments W–N and W–N–W had similar total NUE, and N&W had the lowest total NUE. After harvesting, the total residual fertilizer N in the soil was highest in W–N, lowest in N–W, but this was not significantly different from N&W and W–N–W treatments. Total residual NO₃–N in the soil in N&W and W–N treatments was 20.7 and 21.2% higher than that in N–W, respectively. The total ¹⁵N recovery was not statistically significant between the four fertigation schemes. In this study, the fertigation scheme N–W (nitrogen applied at the beginning of an irrigation cycle) increased DM accumulation, N uptake and NUE of cotton. This study indicates that Nitrogen application at the beginning of an irrigation cycle has an advantage on N uptake and NUE of cotton. Therefore, NUE could be enhanced by optimizing fertilization schemes with drip irrigation.     

Loss of viability during freeze–thaw of intact and adherent human embryonic stem cells with conventional slow-cooling protocols is predominantly due to␣apoptosis rather than cellular necrosis

Summary A major challenge in the widespread application of human embryonic stem (hES) cells in clinical therapy and basic scientific research is the development of efficient cryopreservation protocols. Conventional slow-cooling protocols utilizing standard cryoprotectant concentrations i.e. 10% (v/v) DMSO, yield extremely low survival rates of <5% as reported by previous studies. This study characterized cell death within frozen–thawed hES colonies that were cryopreserved under standard conditions. Surprisingly, our results showed that immediately after post-thaw washing, the overwhelming majority of hES cells were viable (≈98%), as assessed by the trypan blue exclusion test. However, when the freshly-thawed hES colonies were incubated within a 37 °C incubator, there was observed to be a gradual reduction in cell viability over time. The kinetics of cell death was drastically slowed-down by keeping the freshly-thawed hES colonies at 4 °C, with >90% of cells remaining viable after 90 min of incubation at 4 °C. This effect was reversible upon re-exposing the cells to physiological temperature. The vast majority of low temperature-exposed hES colonies gradually underwent cell death upon incubation for a further 90 min at 37 °C. Terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end-labeling (TUNEL) assay confirmed apoptosis-induced nuclear DNA fragmentation in frozen–thawed hES cells after incubation at 37 °C for 90 min. Expression of active caspase-3 enzyme, which is another prominent marker of apoptosis, was confirmed by immunocytochemical staining, while transmission electron microscopy showed typical ultrastructural features of apoptosis such as chromatin condensation and margination to the nuclear membrane. Hence, our results demonstrated that apoptosis instead of cellular necrosis, is the major mechanism of the loss of viability of cryopreserved hES cells during freeze–thawing with conventional slow-cooling protocols.     

The Composition of Microbiome in Larynx and the Throat Biodiversity between Laryngeal Squamous Cell Carcinoma Patients and Control Population

The throat is an ecological assemblage involved human cells and microbiota, and the colonizing bacteria are important factors in balancing this environment. However, this bacterial community profile has thus been poorly investigated. The purpose of this study was to investigate the microbial biology of the larynx and to analyze the throat biodiversity in laryngeal carcinoma patients compared to a control population in a case-control study. Barcoded pyrosequencing analysis of the 16S rRNA gene was used. We collected tissue samples from 29 patients with laryngeal carcinoma and 31 control patients with vocal cord polyps. The findings of high-quality sequence datasets revealed 218 genera from 13 phyla in the laryngeal mucosa. The predominant communities of phyla in the larynx were Firmicutes (54%), Fusobacteria (17%), Bacteroidetes (15%), Proteobacteria (11%), and Actinobacteria (3%). The leading genera were Streptococcus (36%), Fusobacterium (15%), Prevotella (12%), Neisseria (6%), and Gemella (4%). The throat bacterial compositions were highly different between laryngeal carcinoma subjects and control population (p = 0.006). The abundance of the 26 genera was significantly different between the laryngeal cancer and control groups by metastats analysis (p<0.05). Fifteen genera may be associated with laryngeal carcinoma by partial least squares discriminant analysis (p<0.001). In summary, this study revealed the microbiota profiles in laryngeal mucosa from tissue specimens. The compositions of bacteria community in throat were different between laryngeal cancer patients and controls, and probably were related with this carcinoma. The disruption of this bio-ecological niche might be a risk factor for laryngeal carcinoma.     

X-Linked thrombocytopenia causing mutations in WASP (L46P and A47D) impair T cell chemotaxis

Background

Mutation in the Wiskott-Aldrich syndrome Protein (WASP) causes Wiskott-Aldrich syndrome (WAS), X-linked thrombocytopenia (XLT) and X-linked congenital neutropenia (XLN). The majority of missense mutations causing WAS and XLT are found in the WH1 (WASP Homology) domain of WASP, known to mediate interaction with WIP (WASP Interacting Protein) and CIB1 (Calcium and Integrin Binding).

Results

We analyzed two WASP missense mutants (L46P and A47D) causing XLT for their effects on T cell chemotaxis. Both mutants, WASP_R^L46P and WASP_R^A47D (S1-WASP shRNA resistant) expressed well in Jurkat^WASP-KD T cells (WASP knockdown), however expression of these two mutants did not rescue the chemotaxis defect of Jurkat^WASP-KD T cells towards SDF-1α. In addition Jurkat^WASP-KD T cells expressing these two WASP mutants were found to be defective in T cell polarization when stimulated with SDF-1α. WASP exists in a closed conformation in the presence of WIP, however both the mutants (WASP_R^L46P and WASP_R^A47D) were found to be in an open conformation as determined in the bi-molecular complementation assay. WASP protein undergoes proteolysis upon phosphorylation and this turnover of WASP is critical for T cell migration. Both the WASP mutants were found to be stable and have reduced tyrosine phosphorylation after stimulation with SDF-1α.

Conclusion

Thus our data suggest that missense mutations WASP_R^L46P or WASP_R^A47D affect the activity of WASP in T cell chemotaxis probably by affecting the turnover of the protein.

Electronic supplementary material

The online version of this article (doi:10.1186/s12929-014-0091-1) contains supplementary material, which is available to authorized users.     

Immunocytochemistry of ion transport mediators in the genital tract of female rodents

With immunocytochemistry, we have determined distribution of sodium, potassium-adenosine triphosphatase (Na+, K+-ATPase) and of three isoenzymes of carbonic anhydrase (CA) and have shown absence of the chloride channel, Band 3 protein, in the genital tract of female rodents. Staining for Na+,K+-ATPase was strongest in the ampullary oviduct and uterine glands in the mouse. In the mouse and rat ovary, immunostaining evidenced CA I, II, and III in theca interna cells where the enzyme could affect the pH of follicular fluid. The zona pellucida of the ovary and cytoplasmic foci in follicular granulosa cells stained for content of only CA I in mouse ovary, suggesting synthesis of a zona pellucida component by granulosa cells. CA II in mouse oviductal epithelium increased from the negative infundibulum to the variably positive ampulla and isthmus to the uniformly positive interstitial segment. The content of CA III varied inversely to that of CA II. The prevalence of CA II-positive cells apparently corresponded with that of nonciliated cells, whereas abundance of CA III-positive cells concurred with that of ciliated cells in regions of the mouse oviduct. The rat oviduct lacked CA II but, like that of the mouse, showed CA III in the proximal region. The staining for CA II in surface epithelium exceeded the reactivity in glandular epithelium in the mouse uterus, except during estrus. In contrast, rat uterus evidenced CA II in glandular but not surface epithelium. These results testify to possible significance of various ion transport mechanisms for biologic activities of diverse cells in the female genital tract.     

Protective Effect of Levilactobacillus brevis Against Yersinia enterocolitica Infection in Mouse Model via Regulating MAPK and NF-κB Pathway

Probiotics and Antimicrobial Proteins - Although the use of the probiotic bacterium Lactobacillus for the treatment and prevention of diseases caused by various pathogenic bacteria has received...