Gelation behavior and mechanism of low methoxyl pectin in the presence of erythritol and sucrose: The role of co-solutes.

Co-solutes such as sucrose and sugar alcohol play a significant part in low methoxyl pectin (LMP) gelation. To explore their gelation mechanism, we investigated the gelation behavior of LMP in the presence of erythritol and sucrose with Ca2+. Results revealed that the introduction of erythritol and sucrose improved the hardness of the gels, fixed more free water, accelerated the rate of gel structuring, and enhanced the gel strength. FT-IR confirmed the reinforced hydrogen bonding and hydrophobic forces between the pectin chains after introducing co-solutes. And it could be observed clearly by SEM that the cross-linking density of gel network enhanced with co-solutes. Furthermore, gel disruption experiments suggested the presence of ionic interaction, hydrogen bonding, and hydrophobic forces in LMP gels. Finally, we concluded that the egg-box regions cross-linked only by LMP and Ca2+ were too weak to form a stable gel network structure. Adding co-solutes could increase the amount of cross-linking between pectin chains and enlarge the cross-linking zones, which favored the formation of a dense gel network by more hydrogen bonding and hydrophobic forces. Sucrose gels had superior physicochemical properties and microstructure than erythritol gels due to sucrose's excellent hydration capacity and chemical structure characteristics.

Effect of enzymatic de-esterification and RG-I degradation of high methoxyl pectin (HMP) on sugar-acid gel properties.

The influence of RG-I domains on high methoxyl pectin (HMP) sugar-acid gel properties has rarely been reported. In our work, HMP was modified by enzymatic de-esterification and degradation of RG-I domains to compare and analyze the relationship between the structure and final sugar-acid gel properties. The results showed that the degree of esterification (DE) of REP (pectin degraded by rhamnosidase) and GEP (pectin debranched by galactosidase) was the same as that of untreated HMP, whereas the DE of PMEP (pectin de-esterified by pectin methyl esterase) decreased from 59.63 % to 54.69 %. The monosaccharide composition suggested no significant changes in the HG and RG-I structural domains of PMEP. In contrast, the percentage of RG-I structural domains of REP and GEP dropped from 37 % to about 28 %, accompanied by a reduction in the proportion of the RG-I backbones and side chains. The rheological characterization of sugar-acid gels demonstrated an enhanced gel grade for PMEP and a weakened one for REP and GEP. Moreover, we constructed a correlation relationship between the fine structure of pectin and the properties of the sugar-acid gels, confirming the critical contribution of the RG-I region (especially the neutral sugar side chains) to the HMP sugar-acid gels.

[Delivery of epididymis-specific mRNAs from mouse epididymosomes into N2a and TM4 cells].

OBJECTIVE: To investigate whether mouse epididymis-specific mRNAs Adam7 and Crisp1 can be delivered into N2a and TM4 cells, and to provide an experimental basis for exploring the function of epididymal mRNAs. METHODS: Using RT-PCR, we detected the presence of epididymis-specific genes (Adam7, Crisp1, Defb22, Wfdc2, and Wfdc9) in the testis, epididymis, epididymosome and sperm of adult male BALB/c mice as well as in the human testis, seminal vesicles and sperm. We isolated epididymosomes of BALB/c mice by low-speed centrifugation, filtration and ultracentrifugation, fluorescently labeled them by PKH26, co-incubated them for 1 hour with the N2a and TM4 cells after 24 hours of starvation culture, and observed whether they were fused with the N2a and TM4 cells and ingested using the epididymosomes without PKH26 labeling, PKH26 dye without epididymosomes, and non- epididymosome or -PKH26 dye as controls. Then we detected the epididymis-specific genes in the N2a and TM4 cells after 1-hour co-incubation by RT-PCR. RESULTS: Adam7 and Crisp1 were present in the mouse epididymis, epididymosomes and sperm, and in the human seminal vesicles and sperm as well, but not in the testes of either the mice or men. PKH26 and Hoechst33258 fluorescence double-labeling showed that the mouse epididymosomes were fused with the N2a and TM4 cells and ingested; RT-PCR revealed the mRNAs of Adam7 and Crisp1 in the N2a and TM4 cells after 1-hour co-incubation; and Western blot exhibited the CRISP1 protein in the N2a and TM4 cells incubated with epididymosomes. CONCLUSION: Epididymosomes can deliver epididymis-specific mRNAs Adam7 and Crisp1 into N2a and TM4 cells, where Crisp1 may be translated into proteins, though their function and significance need to be further studied.

Helicity-resolved Raman scattering of MoS2 bulk crystal.

Helicity-resolved Raman spectroscopy (HRRS) can effectively distinguish the Raman modes of two-dimensional (2D) layered materials by phonon symmetry. In this paper, we systematically investigated the phonon helicity selection of basal and edge planes of MoS2 bulk by HRRS. We find that the symmetry of the crystal structure changes the helicity selection of the E1g, E1 2g, and A1g modes in the edge plane. The theoretical calculation results confirm that the E1 2g and A1g modes of the basal plane exhibit a perfect helicity exchange, and the helicity selections of the E1 2g and A1g modes of the edge plane are eliminated or weakened. Our study provides references for phonon helicity selection of 2D layered materials represented by MoS2.

Translation and validation of the Chinese version of the MD Anderson symptom inventory for measuring perioperative symptom burden in patients with gynecologic cancer.

BACKGROUND: Gynecologic cancers are among the most prevalent malignancies in China. Cervical and uterine cancer respectively account for the sixth and eighth highest incidence of cancer among Chinese women. Abdominal surgery is one of the important treatment methods for gynecological tumors. However, the tumor- and surgery-related symptom burden are not well studied owing to a lack of a standardized and validated assessment tool in the Chinese population. The study aimed to translate and validate the MD Anderson Symptom Inventory for measuring perioperative symptom burden in gynecologic cancer patients (MDASI-PeriOp-GYN) and examine the utility of the Chinese version of MDASI-PeriOp-GYN. METHODS: The MDASI-PeriOp-GYN was translated in a stepwise manner. First, two native speakers independently translated the 9 PeriOp-GYN symptom items. Then the nine items were translated back into English by two different bilingual translators. After discussion and revision, the four translators reached an agreement. Finally, the finalized Chinese version was administered to women with three common gynecologic cancer types (cervical, ovarian, and endometrial cancers) recruited from the gynecological oncology department of Sichuan Cancer Hospital & Institute between July and October 2019. The reliability and validity of the translated version were assessed. RESULTS: Overall, 324 women with gynecologic cancers were enrolled. Cronbach's α values were 0.826 and 0.735 for the symptom severity and interference scales, respectively. Test-retest reliability values were 0.885, 0.873, and 0.914 for symptom severity, PeriOp-GYN, and interference scales. Significant correlations were found between the MDASI-PeriOp-GYN-C and EORTC QLQ-C30 along with the QLQ-OV28 module (- 0.608-0.871, P < 0.001). Known-group validity was supported by significant differences in the scores of the four scales grouped by time intervals, surgery type, and functional status (all P < 0.01). CONCLUSIONS: The MDASI-PeriOp-GYN-C is a valid and reliable tool for measuring symptoms in Chinese patients undergoing surgery for gynecologic cancers. The tool could be used in clinical practice and clinical trials to instantly gather patients' health and quality of life data.

Rare Primary Pulmonary Primitive Neuroectodermal Tumor: A Case Report and Literature Review.

Primitive neuroectodermal tumors (PNETs) arising from the lung without thoracic wall involvement are extremely rare and particularly aggressive neoplasms. Herein, we present the case of a 41-year-old woman with pulmonary PNET diagnosed following histopathological, immunohistochemical, and molecular pathological examination of a surgical biopsy specimen. The case report is accompanied by a literature review of primary pulmonary PNETs.

Novel approach reveals genomic landscapes of single-strand DNA breaks with nucleotide resolution in human cells.

Single-strand breaks (SSBs) represent the major form of DNA damage, yet techniques to map these lesions genome-wide with nucleotide-level precision are limited. Here, we present a method, termed SSiNGLe, and demonstrate its utility to explore the distribution and dynamic changes in genome-wide SSBs in response to different biological and environmental stimuli. We validate SSiNGLe using two very distinct sequencing techniques and apply it to derive global profiles of SSBs in different biological states. Strikingly, we show that patterns of SSBs in the genome are non-random, specific to different biological states, enriched in regulatory elements, exons, introns, specific types of repeats and exhibit differential preference for the template strand between exons and introns. Furthermore, we show that breaks likely contribute to naturally occurring sequence variants. Finally, we demonstrate strong links between SSB patterns and age. Overall, SSiNGLe provides access to unexplored realms of cellular biology, not obtainable with current approaches.

USP11 regulates p53 stability by deubiquitinating p53.

The p53 tumor suppressor protein coordinates the cellular responses to a broad range of cellular stresses, leading to DNA repair, cell cycle arrest or apoptosis. The stability of p53 is essential for its tumor suppressor function, which is tightly controlled by ubiquitin-dependent degradation primarily through its negative regulator murine double minute 2 (Mdm2). To better understand the regulation of p53, we tested the interaction between p53 and USP11 using co-immunoprecipitation. The results show that USP11, an ubiquitin-specific protease, forms specific complexes with p53 and stabilizes p53 by deubiquitinating it. Moreover, down-regulation of USP11 dramatically attenuated p53 induction in response to DNA damage stress. These findings reveal that USP11 is a novel regulator of p53, which is required for p53 activation in response to DNA damage.

Development of an acellular tumor extracellular matrix as a three-dimensional scaffold for tumor engineering.

Tumor engineering is defined as the construction of three-dimensional (3D) tumors in vitro with tissue engineering approaches. The present 3D scaffolds for tumor engineering have several limitations in terms of structure and function. To get an ideal 3D scaffold for tumor culture, A549 human pulmonary adenocarcinoma cells were implanted into immunodeficient mice to establish xenotransplatation models. Tumors were retrieved at 30-day implantation and sliced into sheets. They were subsequently decellularized by four procedures. Two decellularization methods, Tris-Trypsin-Triton multi-step treatment and sodium dodecyl sulfate (SDS) treatment, achieved complete cellular removal and thus were chosen for evaluation of histological and biochemical properties. Native tumor tissues were used as controls. Human breast cancer MCF-7 cells were cultured onto the two 3D scaffolds for further cell growth and growth factor secretion investigations, with the two-dimensional (2D) culture and cells cultured onto the Matrigel scaffolds used as controls. Results showed that Tris-Trypsin-Triton multi-step treated tumor sheets had well-preserved extracellular matrix structures and components. Their porosity was increased but elastic modulus was decreased compared with the native tumor samples. They supported MCF-7 cell repopulation and proliferation, as well as expression of growth factors. When cultured within the Tris-Trypsin-Triton treated scaffold, A549 cells and human colorectal adenocarcinoma cells (SW-480) had similar behaviors to MCF-7 cells, but human esophageal squamous cell carcinoma cells (KYSE-510) had a relatively slow cell repopulation rate. This study provides evidence that Tris-Trypsin-Triton treated acellular tumor extracellular matrices are promising 3D scaffolds with ideal spatial arrangement, biomechanical properties and biocompatibility for improved modeling of 3D tumor microenvironments.

[Detecting testis- and epididymis-specific methylated promoters in human cell-free seminal DNA by MeDIP-qPCR].

OBJECTIVE: To establish a method of methyl-DNA immunoprecipitation (MeDIP)-real time quantitative PCR (qPCR) for detecting the promoter methylation level in cell-free seminal DNA (cfsDNA). METHODS: We obtained cfsDNA samples from 6 normozoospermia men (the NZ group) and 6 post-vasectomy patients (the PV group), and mixed the samples from different individuals of each group, respectively. Then we made DNA fragments by ultrasonication, separated the methylated DNA fragments by MeDIP, and determined the methylation level of the promoters in cfsDNA by qPCR. RESULTS: The methylation levels of the promoters PRAME, PEG10, MORC1, GML, HOXA5, DNMT3L, SNURF, MSH4, DAZ1 and CLPB were 14.93, 2.64, 0.69, 2.66, 17.50, 21.10, 5.98, 2.28, 13.50 and 3.86%, respectively, in the NZ group, obviously lower than 121.25, 73.62, 16.25, 42.90, 76.74, 112.40, 59.79, 25.85, 91.90 and 64.53% in the PV group. The results of MeDIP-qPCR for the methylation of PRAME, MORC1, GML, HOXA5, DNMT3L, SNURF, MSH4 and DAZ1 were coincident with the results of genome-wide promoter methylation microarray. CONCLUSION: MeDIP-qPCR can quantitatively measure the promoter methylation level in cfsDNA, and effectively determine the testis- and epididymis-specific methylated promoters in human semen.

[Advances in the studies of cell-free seminal DNA].

Cell-free DNA, also referred to as extracellular DNA, has been detected in many kinds of human body fluids, including blood plasma, urine, cerebrospinal fluid, bronchoalveolar lavage fluid, amniotic fluid, and seminal plasma. At present, cell-free DNA has been reported widely as promising noninvasive biomarkers for disease diagnosis and research. Recent years have witnessed some progress in the studies of the general characteristics of cell-free DNA, such as its concentration, extent of molecular weight, origin and existing forms, as well as in its clinical application. Cell-free seminal DNA has been proposed as promising noninvasive biomarkers for the studies and diagnosis of male idiopathic infertility, and the early diagnosis, treatment evaluation and outcome prediction of testicular germ cell tumors and prostatic cancer. This review summarizes the general characteristics and biological functions of cell-free DNA, and outlines the research status and application perspective of cell-free seminal DNA.

The changing trends of HIV/AIDS in an ethnic minority region of China: modeling the epidemic in Liangshan prefecture, Sichuan Province.

OBJECTIVE: This study was to investigate the HIV current situation in Liangshan prefecture, in order to predict prevalence and transmission trends. METHODS: Region-specific population, behavior, serosurveillence, and policy/program data (from 1995 to 2010) were gathered from various local and national organizations and applied to the Asian Epidemic Model (AEM) and used to derive estimates of future HIV prevalence, epidemic trends, and outcomes of intervention strategies. RESULTS: The AEM projections for 2020 included increased number of people living with HIV (PLHIV; to 136 617), increased HIV prevalence (2.51%), and 8037 deaths from acquired immunodeficiency syndrome (AIDS) in this region. However, the overall HIV incidence rate (per 10 000) was projected to decline from 27 in 2015 to 22 in 2020, largely due to a predicted decrease in HIV infection rate (per 10 000) from 658 in 2013 to 621 in 2020 among intravenous drug users. In contrast, the cases of HIV infection per 10 000 was projected to increase from 420 in 2010 to 503 in 2020 among men who have sex with men, and from 8 in 2010 to 15 in 2020 among the general population. The predominant risk factor for HIV transmission over the next decade in Liangshan was casual sex. Community-based outreach strategies to reduce injected drug use and casual sex, and to promote condom use, were predicted as effective interventions to decrease HIV transmission. CONCLUSION: Implementation of a comprehensive public health program, with targeting to the region-specific at-risk populations, will help to mitigate HIV/AIDS spread in Liangshan.

Casual sex and concurrent sexual partnerships among young people from an Yi community with a high prevalence of HIV in China.

Liangshan Prefecture in Sichuan province, China, has a high prevalence of HIV infection, which is reflective of a change in the mode of transmission from injection drug use (IDU) to heterosexual intercourse. However, few studies focus on HIV-related heterosexual risk behaviours among the majority Yi population. The objectives of this study were to explore the characteristics of an egocentric sexual network and estimate the prevalence of casual sexual behaviour. Yi villagers (n=108), aged 15-35 years, who reported having had sex within the previous year were interviewed as to their sexual behaviours and networks. In-depth interviews and focus group discussions provided supplementary information on sexual norms. Logistic regression analysis was used to calculate unadjusted odds ratios (ORs) and 95% confidence intervals (CIs). Most of the respondents reported having had casual sex at some time in their life, and 66.7% reported multiple sexual partnerships. Only 21.3% reported ever having used a condom. During the study year, a total of 137 partners were involved in 153 sexual partnerships. Among the reported sexual partnerships, 67.3% originated from a casual sexual relationship. For network members in components of size ≥ 3, 56.9% were involved in concurrent sexual partnerships. Having never been married (OR: 2.11; 95% CI: 1.03-4.33) and younger age (OR: 0.89; 95% CI: 0.83-0.95) were both associated with being in a component of size ≥ 3. Size (OR: 2.99; 95% CI: 1.17-7.66), pair (OR: 0.54; 95% CI: 0.39-0.74), the number of weak components of the egocentric sexual network (OR: 30.04; 95% CI: 6.47-139.46) and gender (OR: 0.19; 95% CI: 0.06-0.67) were all associated with being in concurrent sexual partnerships. HIV-related interventions for the Yi ethnic minority in Sichuan province must therefore address concurrent sexual partnerships and promote condom use.

Variation in protein intake induces variation in spider silk expression.

BACKGROUND: It is energetically expensive to synthesize certain amino acids. The proteins (spidroins) of spider major ampullate (MA) silk, MaSp1 and MaSp2, differ in amino acid composition. Glutamine and proline are prevalent in MaSp2 and are expensive to synthesize. Since most orb web spiders express high proline silk they might preferentially attain the amino acids needed for silk from food and shift toward expressing more MaSp1 in their MA silk when starved. METHODOLOGY/PRINCIPAL FINDINGS: We fed three spiders; Argiope aetherea, Cyrtophora moluccensis and Leucauge blanda, high protein, low protein or no protein solutions. A. aetherea and L. blanda MA silks are high in proline, while C. moluccesnsis MA silks are low in proline. After 10 days of feeding we determined the amino acid compositions and mechanical properties of each species' MA silk and compared them between species and treatments with pre-treatment samples, accounting for ancestry. We found that the proline and glutamine of A. aetherea and L. blanda silks were affected by protein intake; significantly decreasing under the low and no protein intake treatments. Glutmaine composition in C. moluccensis silk was likewise affected by protein intake. However, the composition of proline in their MA silk was not significantly affected by protein intake. CONCLUSIONS: Our results suggest that protein limitation induces a shift toward different silk proteins with lower glutamine and/or proline content. Contradictions to the MaSp model lie in the findings that C. moluccensis MA silks did not experience a significant reduction in proline and A. aetherea did not experience a significant reduction in serine on low/no protein. The mechanical properties of the silks could not be explained by a MaSp1 expressional shift. Factors other than MaSp expression, such as the expression of spidroin-like orthologues, may impact on silk amino acid composition and spinning and glandular processes may impact mechanics.

[Genetic structure of wild Macrobrachium nipponense populations in Taihu Lake based on microsatellite analysis].

By using eight highly polymorphic microsatellite DNA loci, this paper analyzed the genetic structure of wild Macrobrachium nipponense populations in Taihu Lake. For the 15 M. nipponense populations in the Lake, there were at least three of the loci presenting heterozygosity deficiency and obvious deviation from Hardy-Weinberg equilibrium after Bonferroni correction. The observed heterozygosity values of the 15 populations were all above 0. 683, displaying a high genetic diversity, but the diversity varied obviously with site. For example, the genetic diversity of the eastern and southern populations at Dukou and Luxiang was higher than that of the western and northern populations at Huazhuang and Yangzhu. For the 15 populations, parts of the loci showed heterozygote excess and departure from mutation-drift equilibrium, suggesting that the population structure had experienced bottleneck effect and the population amount had declined. The AMOVA analysis across all the populations and loci showed that the genetic divergence among the 15 populations was at a lower level (F(ST) = 0.011 ). 98.9% of the genetic variation came from intra-population, and 1.1% came from inter-population, suggesting that all the M. nipponense populations in the Lake could be protected and managed as a single unit in genetic resource. However, the genetic distance between Huazhuang and Wutangmen populations reached 0.206, being close to the delimitation of species identification. Further studies would be needed for the sustainable utilization of the genetic resource of M. nipponense in Taihu Lake.

New electrocatalysts for unitized regenerative fuel cell: Pt-Ir alloy deposited on the proton exchange membrane surface by impregnation-reduction method.

In this paper, a modified technique to prepare Pt-Ir catalyst layer on the proton exchange membrane (PEM) surface using the impregnation-reduction (IR) method is proposed to improve the electrocatalytic activity as well as the life cycle of the bifunctional oxygen electrode (BOE). The resulted electrocatalysts were characterized by the Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Electron Probe Micro-Analysis (EPMA), and Transmission Electron Microscope (TEM). The electrocatalytic properties of the Pt-Ir layer on PEM surface for the oxygen reduction and water oxidation reactions as well as the life cycle of MEA were investigated. Experimental results showed that the Ir particles were dispersed densely in the platinum layer through the modified IR technique. The atomic ratio of Pt over Ir elements was 9:1, and the resulted thickness of the obtained Pt-Ir catalyst layer was about 1.0 microm. The Pt-Ir catalyst layer was composed of Pt layer doped with Ir nano-particles comprising nano Pt-Ir alloy phase. The large surface area of Ir core with Pt shell particles and the presence of nano Pt-Ir alloy phase led to a higher electrocatalytic activity of BOE. Due to the good binding between the Nafion membrane and the Pt-Ir alloy catalyst, as well as the composite structure of the resulted Pt-Ir, the life cycle of Unitized Regenerative Fuel Cell (URFC) is improved through this novel BOE.

Dynamics and evolution of the inverted repeat-large single copy junctions in the chloroplast genomes of monocots.

BACKGROUND: Various expansions or contractions of inverted repeats (IRs) in chloroplast genomes led to fluxes in the IR-LSC (large single copy) junctions. Previous studies revealed that some monocot IRs contain a trnH-rps19 gene cluster, and it has been speculated that this may be an evidence of a duplication event prior to the divergence of monocot lineages. Therefore, we compared the organizations of genes flanking two IR-LSC junctions in 123 angiosperm representatives to uncover the evolutionary dynamics of IR-LSC junctions in basal angiosperms and monocots. RESULTS: The organizations of genes flanking IR-LSC junctions in angiosperms can be classified into three types. Generally each IR of monocots contains a trnH-rps19 gene cluster near the IR-LSC junctions, which differs from those in non-monocot angiosperms. Moreover, IRs expanded more progressively in monocots than in non-monocot angiosperms. IR-LSC junctions commonly occurred at polyA tract or A-rich regions in angiosperms. Our RT-PCR assays indicate that in monocot IRA the trnH-rps19 gene cluster is regulated by two opposing promoters, S10A and psbA. CONCLUSION: Two hypotheses are proposed to account for the evolution of IR expansions in monocots. Based on our observations, the inclusion of a trnH-rps19 cluster in majority of monocot IRs could be reasonably explained by the hypothesis that a DSB event first occurred at IRB and led to the expansion of IRs to trnH, followed by a successive DSB event within IRA and lead to the expansion of IRs to rps19 or to rpl22 so far. This implies that the duplication of trnH-rps19 gene cluster was prior to the diversification of extant monocot lineages. The duplicated trnH genes in the IRB of most monocots and non-monocot angiosperms have distinct fates, which are likely regulated by different expression levels of S10A and S10B promoters. Further study is needed to unravel the evolutionary significance of IR expansion in more recently diverged monocots.