Characterization of Serracin P, a Phage-Tail-Like Bacteriocin, and Its Activity against Erwinia amylovora, the Fire Blight Pathogen

Serratia plymithicum J7 culture supernatant displayed activity against many pathogenic strains of Erwinia amylovora, the causal agent of the most serious bacterial disease of apple and pear trees, fire blight, and against Klebsiella pneumoniae, Serratia liquefaciens, Serratia marcescens, and Pseudomonas fluorescens. This activity increased significantly upon induction with mitomycin C. A phage-tail-like bacteriocin, named serracin P, was purified from an induced culture supernatant of S. plymithicum J7. It was found to be the only compound involved in the antibacterial activity against sensitive strains. The N-terminal amino acid sequence analysis of the two major subunits (23 and 43 kDa) of serracin P revealed high homology with the Fels-2 prophage of Salmonella enterica, the coliphages P2 and 168, the CTX prophage of Pseudomonas aeruginosa, and a prophage of Yersinia pestis. This strongly suggests a common ancestry for serracin P and these bacteriophages.     

Headspace Solid Phase Microextraction Coupled to GC/MS for the Analysis of Volatiles of Honeys from Arid and Mediterranean Areas of Algeria

The volatile composition of seven honey samples collected from various regions of Algeria and feeding on different plants have been determined. The Headspace Solid‐Phase MicroExtraction (HS‐SPME) coupled with Gas Chromatography‐Mass Spectrometry (GC/MS) was used to achieve the purpose. In this work, different parameters of the HS‐SPME analytical method were investigated in order to reach maximal sensitivity, and thus to obtain maximum information about the volatile profile of Algerian honey. These parameters include saline medium, HS extraction temperature, and the nature of the fiber used. The results showed a great diversity in the chemical composition, in total 124 compounds from different chemical classes were identified, including compounds found for the first time in honey. The Ascending Hierarchical Classification (AHC) demonstrated the importance of choosing SPME extraction conditions to find volatile compounds, which could be as specific markers of the floral or geographical origin of honey, the latter was optimized in the parameter PDMS‐55 °C.     

Validation of the Chinese Version of the Quality of Nursing Work Life Scale

Quality of Nursing Work Life (QNWL) serves as a predictor of a nurse’s intent to leave and hospital nurse turnover. However, QNWL measurement tools that have been validated for use in China are lacking. The present study evaluated the construct validity of the QNWL scale in China. A cross-sectional study was conducted conveniently from June 2012 to January 2013 at five hospitals in Guangzhou, which employ 1938 nurses. The participants were asked to complete the QNWL scale and the World Health Organization Quality of Life abbreviated version (WHOQOL-BREF). A total of 1922 nurses provided the final data used for analyses. Sixty-five nurses from the first investigated division were re-measured two weeks later to assess the test-retest reliability of the scale. The internal consistency reliability of the QNWL scale was assessed using Cronbach’s α. Test-retest reliability was assessed using the intra-class correlation coefficient (ICC). Criterion-relation validity was assessed using the correlation of the total scores of the QNWL and the WHOQOL-BREF. Construct validity was assessed with the following indices: χ² statistics and degrees of freedom; relative mean square error of approximation (RMSEA); the Akaike information criterion (AIC); the consistent Akaike information criterion (CAIC); the goodness-of-fit index (GFI); the adjusted goodness of fit index; and the comparative fit index (CFI). The findings demonstrated high internal consistency (Cronbach’s α = 0.912) and test-retest reliability (interclass correlation coefficient = 0.74) for the QNWL scale. The chi-square test (χ² = 13879.60, df [degree of freedom] = 813 P = 0.0001) was significant. The RMSEA value was 0.091, and AIC = 1806.00, CAIC = 7730.69, CFI = 0.93, and GFI = 0.74. The correlation coefficient between the QNWL total scores and the WHOQOL-BREF total scores was 0.605 (p<0.01). The QNWL scale was reliable and valid in Chinese-speaking nurses and could be used as a clinical and research instrument for measuring work-related factors among nurses in China.     

The p75 neurotrophin receptor is a central regulator of glioma invasion

The invasive nature of cancers in general, and malignant gliomas in particular, is a major clinical problem rendering tumors incurable by conventional therapies. Using a novel invasive glioma mouse model established by serial in vivo selection, we identified the p75 neurotrophin receptor (p75^NTR) as a critical regulator of glioma invasion. Through a series of functional, biochemical, and clinical studies, we found that p75^NTR dramatically enhanced migration and invasion of genetically distinct glioma and frequently exhibited robust expression in highly invasive glioblastoma patient specimens. Moreover, we found that p75^NTR-mediated invasion was neurotrophin dependent, resulting in the activation of downstream pathways and producing striking cytoskeletal changes of the invading cells. These results provide the first evidence for p75^NTR as a major contributor to the highly invasive nature of malignant gliomas and identify a novel therapeutic target.     

OPTIMIZATION OF SOME HEAVY METALS BIOSORPTION BY REPRESENTATIVE EGYPTIAN MARINE ALGAE1

Marine algae—as inexpensive and renewable natural biomass—have attracted the attention of many investigators to be used to preconcentrate and biosorb many heavy metal ions. Impressed by this concept, the metal uptake capacity of Egyptian marine algae was examined using representatives of green and brown algae, namely, Ulva lactuca L. and Sargassum latifolium (Turner) C. Agardh, respectively. The biosorption efficiencies of Cu²⁺, Co²⁺, Ni²⁺, Cd²⁺, Hg²⁺, Ag²⁺, and Pb²⁺ ions seem to depend on the type of the algae used as well as the conditions under which the uptake processes were conducted. It was demonstrated that a pH range of 7.5–8.8 was optimum for the removal of the tested metals. Similarly, the uptake process was markedly accelerated during the first 2 h using relatively low metal level and sufficient amounts of the dried powdered tested algae.     

Altered antioxidant status and increased lipid per-oxidation in seminal plasma of tunisian infertile men

Human seminal plasma is a natural reservoir of antioxidants that protect spermatozoa from oxidative damages. There is evidence in literature supports the fact that impairments in seminal antioxidant and lipid per-oxidation status play important roles in the physiopathology of male infertility. Our present study forms the first one which was carried out in Tunisia. We evaluated the antioxidant status in the seminal plasma of 120 infertile men programmed to In Vitro Fertilization (IVF) for the first tentative. Patients were characterized by an idiopathic infertility. They were divided into three groups: normozoospermics who were considered as controls (n=40), asthenozoospermics (Astheno; n=45) and oligoasthenoteratozoospermics (OAT; n=35). Seminal activities of superoxide dismutase (SOD) and glutathione peroxidase (GPX) and the levels of glutathione (GSH), zinc (Zn) and malondialdehyde (MDA) were measured. With the significant increase of the seminal activities of SOD and GPX in normozoospermics group, there were positive correlations observed between this enzymes and sperm quality. Also, significant elevated rates of seminal zinc and GSH were observed in control group, but there was contradictory associations reflecting the effects of these antioxidants on semen parameters. However, we noted significant increase of MDA levels in groups with abnormal seminogram. We showed negative associations between this per-oxidative marker and sperm parameters. These results obviously suggested that impairment on seminal antioxidants is an important risk factor for low sperm quality associated to idiopathic infertility and as a result can lead to poor IVF outcome.     

混合盐碱胁迫下接种丛枝菌根真菌和根瘤菌对紫花苜蓿生长的影响

随着气候变化,全球土壤盐碱化严重威胁着农牧业生产和生态环境的建设。土壤盐化与碱化常常伴随发生,目前多数研究侧重于盐胁迫,忽略了碱胁迫的存在。实际上,碱性盐除了盐度外还伴随着高p H。由此,试图探讨混合盐碱胁迫下接种丛枝菌根真菌(AMF)和根瘤菌对紫花苜蓿生长的影响及其作用机理。根据中国盐碱地的特点,将4种盐(Na Cl、Na_2SO_4、Na_2CO_3、Na HCO_3)按一定比例混合模拟出16种混合盐碱(盐浓度25—150 mmol/L,p H 7.67—10.52)胁迫浓度,按照L_(16)(16~1×2~2)混合正交设计,采用盆栽法研究了混合盐碱胁迫下接种AMF摩西管柄囊霉(Funneliformis mosseae)和根瘤菌(Sinorhizobium meliloti)对紫花苜蓿生长及生理的影响。结果表明:对紫花苜蓿株高的影响程度依次是AMF+根瘤菌pHAMF盐碱类型根瘤菌;对地上生物量、地下生物量、茎高净增长量、丙二醛(MDA)及脯氨酸影响程度依次是p HAMF+根瘤菌盐碱类型AMF根瘤菌;对超氧化物歧化酶(SOD)的影响程度依次是p HAMF+根瘤菌盐碱类型AMF根瘤菌;对过氧化物酶(POD)影响程度依次是p HAMF+根瘤菌根瘤菌AMF盐碱类型;对蛋白质的影响程度依次是p H盐碱类型根瘤菌AMF+根瘤菌=AMF。株高、地下生物量、POD均在双接种的处理下出现最大值。本研究证明:盐碱混合胁迫会严重抑制植物的生长发育;而接种AMF和/或根瘤菌均可有效缓解盐碱胁迫对植物造成的伤害,提高植物对盐碱的耐受能力;且同时接种AMF及根瘤菌效果最好,其次是单独接种AMF,单独接种根瘤菌作用相对最小。