The ING4 Binding with p53 and Induced p53 Acetylation were Attenuated by Human Papillomavirus 16 E6

High risk subtype HPV16 early oncoprotein E6 contributes host cell immortalization and transformation through interacting with a number of cellular factors. ING4 is one member of the inhibitor of growth (ING) family of type II tumor suppressors and it has been shown to be involved in regulating p53 function. However, the effect and mechanism of HPV16 E6 on ING4 function remain elusive. In this study, we report HPV16 E6 combines with ING4 in vivo and in vitro. The ING4 induced p53 acetylation and its combining with p53 were attenuated by HPV16 E6 independent of p53 degradation. The enhancing function of ING4 on p53 mediated apoptosis was diminished when HPV16 E6 existed. These findings reveal that ING4 may be a common target of oncogenic viruses for driving host cell carcinogenesis.     

Probiotic Therapy (BIO-THREE) Mitigates Intestinal Microbial Imbalance and Intestinal Damage Caused by Oxaliplatin

Probiotics and Antimicrobial Proteins - Gastrointestinal mucositis associated with the use of chemotherapeutic drugs can seriously affect the quality of life of patients. In this study, a probiotic...     

Spatial Change of Cruciate Ligaments in Rat Embryo Knee Joint by Three-Dimensional Reconstruction

This study aimed to analyze the spatial developmental changes of rat cruciate ligaments by three-dimensional (3D) reconstruction using episcopic fluorescence image capture (EFIC). Cruciate ligaments of Wister rat embryos between embryonic day (E) 16 and E20 were analyzed. Samples were sectioned and visualized using EFIC. 3D reconstructions were generated using Amira software. The length of the cruciate ligaments, distances between attachment points to femur and tibia, angles of the cruciate ligaments and the cross angle of the cruciate ligaments were measured. The shape of cruciate ligaments was clearly visible at E17. The lengths of the anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) increased gradually from E17 to E19 and drastically at E20. Distances between attachment points to the femur and tibia gradually increased. The ACL angle and PCL angle gradually decreased. The cross angle of the cruciate ligaments changed in three planes. The primordium of the 3D structure of rat cruciate ligaments was constructed from the early stage, with the completion of the development of the structures occurring just before birth.     

Desulfovibrio vulgaris Hildenborough prefers lactate over hydrogen as electron donor

Desulfovibrio vulgaris can use lactate as an electron donor and accumulate hydrogen. Hydrogen can also be consumed as an electron donor when lactate is depleted or absent. The aim of this study was to determine whether D. vulgaris has an electron donor preference system between lactate and hydrogen and how this system is regulated. In order to be sure that D. vulgaris was grown under the same conditions except for electron donors, continuous growth mode was conducted and the optical density (600 nm) was kept constant. When 20 mmol/l lactate was the sole electron donor, it was depleted after 9 h of incubation while hydrogen was accumulated to 1,500 ppm. After that, the hydrogen level was decreased to and maintained at 400 ppm. When 1,200 ppm hydrogen was provided as the electron donor, the culture reached an OD of 0.2 after 24 h incubation and hydrogen was consumed to 600 ppm. When 1,200 ppm hydrogen and 20 mmol/l lactate were both present, the lactate was consumed during the first 9 h incubation and hydrogen was accumulated to 1,800 ppm. D. vulgaris used hydrogen as an electron donor after the lactate was depleted and the hydrogen level was decreased to 600 ppm. D. vulgaris has both pathways to utilize lactate and hydrogen as electron donors. It prefers lactate over hydrogen and the system is regulated by lactate starvation.     

Regulation of arsenate resistance in Desulfovibrio desulfuricans G20 by an arsRBCC operon and an arsC gene

Desulfovibrio desulfuricans G20 grows and reduces 20 mM arsenate to arsenite in lactate-sulfate media. Sequence analysis and experimental data show that D. desulfuricans G20 has one copy of arsC and a complete arsRBCC operon in different locations within the genome. Two mutants of strain G20 with defects in arsenate resistance were generated by nitrosoguanidine mutagenesis. The arsRBCC operons were intact in both mutant strains, but each mutant had one point mutation in the single arsC gene. Mutants transformed with either the arsC1 gene or the arsRBCC operon displayed wild-type arsenate resistance, indicating that the two arsC genes were equivalently functional in the sulfate reducer. The arsC1 gene and arsRBCC operon were also cloned into Escherichia coli DH5alpha independently, with either DNA fragment conferring increased arsenate resistance. The recombinant arsRBCC operon allowed growth at up to 50 mM arsenate in LB broth. Quantitative PCR analysis of mRNA products showed that the single arsC1 was constitutively expressed, whereas the operon was under the control of the arsR repressor protein. We suggest a model for arsenate detoxification in which the product of the single arsC1 is first used to reduce arsenate. The arsenite formed is then available to induce the arsRBCC operon for more rapid arsenate detoxification.     

Drought stress and plant ecotype drive microbiome recruitment in switchgrass rhizosheath

The rhizosheath, a layer of soil grains that adheres firmly to roots, is beneficial for plant growth and adaptation to drought environments. Switchgrass is a perennial C4 grass which can form contact rhizosheath under drought conditions. In this study, we characterized the microbiomes of four different rhizocompartments of two switchgrass ecotypes (Alamo and Kanlow) grown under drought or well-watered conditions via 16S ribosomal RNA amplicon sequencing. These four rhizocompartments, the bulk soil, rhizosheath soil, rhizoplane, and root endosphere, harbored both distinct and overlapping microbial communities. The root compartments (rhizoplane and root endosphere) displayed low-complexity communities dominated by Proteobacteria and Firmicutes. Compared to bulk soil, Cyanobacteria and Bacteroidetes were selectively enriched, while Proteobacteria and Firmicutes were selectively depleted, in rhizosheath soil. Taxa from Proteobacteria or Firmicutes were specifically selected in Alamo or Kanlow rhizosheath soil. Following drought stress, Citrobacter and Acinetobacter were further enriched in rhizosheath soil, suggesting that rhizosheath microbiome assembly is driven by drought stress. Additionally, the ecotype-specific recruitment of rhizosheath microbiome reveals their differences in drought stress responses. Collectively, these results shed light on rhizosheath microbiome recruitment in switchgrass and lay the foundation for the improvement of drought tolerance in switchgrass by regulating the rhizosheath microbiome.     

Targeting LSD1 suppresses stem cell-like properties and sensitizes head and neck squamous cell carcinoma to PD-1 blockade

Head and neck squamous cell carcinoma (HNSCC) is a highly aggressive tumor with poor clinical outcomes due to recurrence, metastasis, and treatment resistance. Cancer stem cells (CSCs), a small population among tumor cells, are proposed to be responsible for tumor initiation, progression, metastasis, drug resistance, and recurrence. Here we show that high LSD1 expression was a predictor of poor prognosis for HNSCC patients. We found that high expression of LSD1 is essential for the maintenance of the CSC properties by regulating Bmi-1 expression. Moreover, tumor LSD1 ablation suppresses CSC-like characteristics in vitro and inhibits tumorigenicity in vivo in immune-deficient xenografts. However, this deletion induces the upregulation of PDL1 levels, which compromises antitumor immunity and reduces antitumor efficacy in an immune-competent mouse model. Functionally, the combination of LSD1 inhibitor and anti-PD-1 monoclonal antibody can overcome tumor immune evasion and greatly inhibit tumor growth, which was associated with reduced Ki-67 level and augmented CD8⁺ T cell infiltration in immunocompetent tumor-bearing mouse models. In summary, these findings provide a novel and promising combined strategy for the treatment of HNSCC using a combination of LSD1 inhibition and PD-1 blockade.Subject terms: Oral cancer, Stem-cell research     

Functional Studies of Split Arabidopsis Ca2+/H+ Exchangers

In plants, high capacity tonoplast cation/H⁺ antiport is mediated in part by a family of cation exchanger (CAX) transporters. Functional association between CAX1 and CAX3 has previously been shown. In this study we further examine the interactions between CAX protein domains through the use of nonfunctional halves of CAX transporters. We demonstrate that a protein coding for an N-terminal half of an activated variant of CAX1 (sCAX1) can associate with the C-terminal half of either CAX1 or CAX3 to form a functional transporter that may exhibit unique transport properties. Using yeast split ubiquitin, in planta bimolecular fluorescence complementation, and gel shift experiments, we demonstrate a physical interaction among the half proteins. Moreover, the half-proteins both independently localized to the same yeast endomembrane. Co-expressing variants of N- and C-terminal halves of CAX1 and CAX3 in yeast suggested that the N-terminal region mediates Ca²⁺ transport, whereas the C-terminal half defines salt tolerance phenotypes. Furthermore, in yeast assays, auto-inhibited CAX1 could be differentially activated by CAX split proteins. The N-terminal half of CAX1 when co-expressed with CAX1 activated Ca²⁺ transport, whereas co-expressing C-terminal halves of CAX variants with CAX1 conferred salt tolerance but no apparent Ca²⁺ transport. These findings demonstrate plasticity through hetero-CAX complex formation as well as a novel means to engineer CAX transport.     

大黄欧文氏菌蔗糖异构酶控制产物特异性基序的定点突变

大黄欧文氏菌(Erwinia rhapontici)蔗糖异构酶催化蔗糖异构为异麦芽酮糖和海藻酮糖,具有一个可能控制产物特异性的325RLDRD329基序.本研究以定点突变方法对该基序的带电荷氨基酸进行突变,共构建R325D、R328A、R328D、R328Q和D329N 5个突变体.通过对突变体的酶学特性及突变体转化蔗糖的产物组成分析,结果显示所构建突变体的Km值上升约2~5倍,比活力下降至野生型SI比活力的11.8%~25.3%.HPLC分析显示Arg325和Arg328分别突变为Asp,导致产物中异麦芽酮糖/海藻酮糖的比例从6.93分别降至0.96和2.92,并伴随一个未知寡糖出现.Arg328突变为Ala和Gln同样导致反应产物中海藻酮糖比例上升,异麦芽酮糖比例下降.但是突变体D329N反应产物比例没有变化.以上结果表明325RLDRD329基序对大黄欧文氏菌蔗糖异构酶的酶活具有重要作用,并对酶的产物特异性产生影响.本研究结果将为该酶的作用机理研究奠定基础.     

A copper‐specific microbial fuel cell biosensor based on riboflavin biosynthesis of engineered Escherichia coli

Copper pollution poses a serious threat to the aquatic environment; however, in situ analytical methods for copper monitoring are still scarce. In the current study, Escherichia coli Rosetta was genetically modified to express OprF and ribB with promoter P_t7 and P_cusC, respectively, which could synthesize porin and senses Cu²⁺ to produce riboflavin. The cell membrane permeability of this engineered strain was increased and its riboflavin production (1.45–3.56 μM) was positively correlated to Cu²⁺ (0–0.5 mM). The biosynthetic strain was then employed in microbial fuel cell (MFC) based biosensor. Under optimal operating parameters of pH 7.1 and 37°C, the maximum voltage (248, 295, 333, 352, and 407 mV) of the constructed MFC biosensor showed a linear correlation with Cu²⁺ concentration (0.1, 0.2, 0.3, 0.4, 0.5 mM, respectively; R² = 0.977). The continuous mode testing demonstrated that the MFC biosensor specifically senses Cu²⁺ with calculated detection limit of 28 μM, which conforms to the common Cu²⁺ safety standard (32 μM). The results obtained with the developed biosensor system were consistent with the existing analytical methods such as colorimetry, flame atomic absorption spectrometry, and inductively coupled plasma optical emission spectrometry. In conclusion, this MFC‐based biosensor overcomes the signal conversion and transmission problems of conventional approaches, providing a fast and economic analytical alternative for in situ monitoring of Cu²⁺ in water.