经细菌载体投递的基因融合肽口服免疫对热稳定性大肠杆菌肠毒素的粘膜保护作用

经细菌载体投递的基因融合肽口服免疫对热稳定性大肠杆菌肠毒素的粘膜保护作用肠毒素是大肠杆菌引起腹泻的重要原因。大肠杆菌除了产生分子量较高、热不稳定的肠毒素（ＬＴ）外,还能产生一种分子量较低、热稳定肠毒素（ＳＴ）,因其分子量低,免疫原性也就相对较差,但将...     

Accumulation of scopoletin is associated with the high disease resistance of the hybrid Nicotiana glutinosa x Nicotiana debneyi

The high disease resistance of the amphidiploid hybrid of Nicotiana glutinosa x Nicotiana debneyi is associated with high constitutive levels of two phenolic compounds as analysed by high-performance liquid chromatography. The structures of these two compounds were elucidated by means of gas chromatography-tandem mass spectrometry, fluorescence- and light-spectrophotometry to be those of scopolin and scopoletin. They reached levels of 4 nmol·(g FW)^?1 and 35 nmol·(g FW)^?1, respectively, in leaf tissues of the hybrid, about 10–50 times the amount found in the parental species. Scopoletin showed a direct antimicrobial activity against Cercospora nicotianae, Phytophthora parasitica var. nicotianae, Pseudomonas syringae pvs. tabaci and syringae and tobacco mosaic virus when added to synthetic growth media, mixed with the inoculum or sprayed onto tobacco plants prior to inoculation. We postulate that the high amount of toxic phenolics in the leaves of the hybrid N. glutinosa x N. debneyi contributes to its high disease resistance.     

Influence of A1 cytoplasmic substitution on the downy-mildew incidence of pearl millet

Large-scale cultivation of pearl millet [Pennisetum glaucum (L.) R. Br. F₁ hybrids in India has led to increased incidence of downy-mildew (Sclerospora graminicola). There is concern that the A₁ male-sterile cytoplasm used in all the hybrids released so far is responsible for this increase. The influence of A₁ malesterile cytoplasm on downy-mildew incidence in pearl millet was studied by comparing the disease reaction of 40 pairs of F₁ hybrids, each pair carrying respectively a₁ male-sterile and normal B cytoplasm. Mean downy-mildew incidence was similar in the hybrids carrying either A₁ male-sterile or B cytoplasm. The general combining ability of lines with and without A₁ cytoplasm was found to be similar for downy-mildew incidence. These results indicated that in pearl millet A₁ cytoplasm is not associated with increased downymildew incidence. The possible danger of using only one source of cytoplasm has been briefly discussed.     

禾谷缢蚜对小麦黄矮病传播能力变异的研究

测试结果禾谷缢蚜对小麦黄矮病(BYDV)传播能力显著提高。由此可使该病由北方干旱,半干旱的中、低产麦区往水地高产麦区,甚至南方麦区扩展曼延。已于1988、1989年秋季导致陕西关中西部水地,1989年春季导致南方麦区四川荣县小麦黄矮病发生流行。     

宁夏甜菜丛根病的研究

发生在宁夏甜菜上的一种病毒病的病株叶丛主要表现为黄化、焦桔和叶脉黄化坏死。从其分离的病毒粒子呈杆状,宽约20nm,长度为65—110nm、270—300nm和390—420nm,能侵染甜菜、菠菜、昆诺阿藜、苋色藜、番杏,与甜菜坏死黄脉病毒(BNYVV)抗血清呈阳性反应。综上所述,认为该病害是由BNYVV引起的。     

Nucleotide Sequence Assessment of Four ORFs of Citrus Tristeza Virus: Evidence of Recombination

Citrus Tristeza Virus (CTV), usually occurs in nature as a mixture of genotypes. Six naturally infected citrus (Citrus sinensis) trees grafted on sour orange rootstock were collected from three citrus growing governorates in Egypt (Sharqia, Qalyubia and Garbia). In this study, RT-PCR, Single-Strand Conformation Polymorphism (SSCP) and nucleotide sequence analysis were used for four independent CTV genomic regions (p65, p18, p20, and p23) to detect and assess the sequence and genetic variabilities among CTV Egyptian isolates. RTPCR products (650 bp) for the CTV p23 gene obtained from the selected isolates were used for the SSCP analysis and DNA sequencing. SSCP patterns of p23 gene for individual isolates yielded different complex haplotype patterns. Nucleotide sequence analysis of p23 region amplified from six isolates under study revealed that p23 shared high nucleotide identity 98.7% with T36 isolate from USA, Florida. Phylogenetic analysis of p23 gene indicated a close evolutionary relationship between all examined isolates and Qaha isolate (T36 isolate group), suggesting that they may have originated from closely related ancestors. Nucleotide sequence analysis of the three genes located on CTV 3′-coterminal overhang, p18, p20 and p65, amplified from isolate A3, Sharqia governorate, revealed that the p18, p65, and p20 genes were related to the T3-KB isolate from South Africa with 99%–100% sequence homology. Phylogenetic relationship analysis for p65, p18 and p20 ORFs clustered the current A3 isolate with T3 genotype group. The recombination analysis identified three of six isolates from Sharqia, and Garbia as potential recombinant for p23 gene. The isolates T36 and T3 were identified as major donors for recombination events in isolate A3. Our results concluded that p23 ORF likely to be as a hotspot region for recombination and originated through recombination event. The current study indicated that recombination is an important factor for the origin of CTV strains in Egypt.     

Factores de riesgo asociados a fallecimiento por la variante ómicron de COVID-19: análisis retrospectivo con personas mayores de Canarias

Background and aimsSince the beginning of the COVID-19 pandemic, the elderly population has had the highest rates of complications and mortality. This study aimed to determine the influence of different risk factors on deaths due to the Omicron variant in the Canary Islands.Materials and methodsA retrospective observational study of 16,998 cases of COVID-19 over 40 years of age was conducted in the Canary Islands between August 1, 2022, and January 31, 2023. We extracted sociodemographic data (age and sex) and clinical data (death, vaccination history, hospital admission, previous diseases, and treatments).ResultsAmong the deaths, there was a higher proportion of males aged over 70 years, with diabetes, cardiovascular, renal, respiratory, and systemic diseases, and nursing home residents. Significant differences were observed in the number of doses of the vaccine. The multiple regression model showed that male sex (OR [95% CI] = 1.92 [1.42–2.58]), age (70–79 years, 9.11 [4.27–19.43]; 80–89 years, 21.72 [10.40–45.36]; 90–99 years, 66.24 [31.03–141.38]; 100 years or older, 69.22 [12.97–369.33]), being unvaccinated (6.96, [4.01–12.08]), or having the last dose administered at least 12 months before the diagnosis (2.38, [1.48–3.81]) were significantly associated with mortality.ConclusionsMultiple factors may increase the risk of mortality due to COVID-19 in the elderly population. In our study, we found that only three predictors can effectively explain the variability: older age, male sex, and not being vaccinated or last vaccination date prior to one year.     

茶刺蛾颗粒体病毒病毒粒子的表面增强拉曼散射(SERS)光谱研究

得到并分析了茶刺蛾颗粒体病毒(Darna trima Granulosis Virus缩写为DtGV)病毒粒子的SERS谱.DtGV病毒粒子通过COO(COOH)和NH_2(NH_3)基因被吸附到银溶胶表面上.Trp、Tyr和Phe残基侧链靠近银表面、以Trp残基侧链的振动增强效应最显著.上还增强特性与溶液的pH值密切相关.     

铜蓝蛋白、鳞状细胞癌相关抗原与慢性肾功能衰竭的关系及对病情进展的预测价值研究

摘要 目的：分析铜蓝蛋白（CER）、鳞状细胞癌相关抗原（SCCA）与慢性肾功能衰竭的关系及对病情进展的预测价值。方法：选择我院自2019年4月至2021年4月接诊的169例慢性肾功能衰竭患者作为研究对象,根据24 h尿白蛋白定量分为微量白蛋白尿组（＜200 mg/24 h,102例）和大量白蛋白尿组（＞200 mg/24 h,67例）。比较两组各项实验室指标及血清CER、SCCA水平,分析CER、SCCA与慢性肾功能衰竭患者肾功能指标的关系。随访12个月,观察病情进展,使用受试者工作特征曲线（ROC）评价血清CER联合SCCA对病情进展的预测效能。结果：大量白蛋白尿组血清肌酐（Scr）、血尿素氮（BUN）水平均明显高于微量白蛋白尿组,肾小球滤过率（GFR）低于微量白蛋白尿组（P＜0.05）;大量白蛋白尿组血清CER、SCCA水平均高于微量白蛋白尿组（P＜0.05）;经Pearson相关性分析,慢性肾功能衰竭患者血清CER、SCCA水平均与Scr、BUN呈正相关,与GFR呈负相关（P＜0.05）;经多因素Logistic回归分析,GFR、CER、SCCA均是慢性肾功能衰竭患者病情进展的独立预测因素（P＜0.05）;经ROC曲线分析,血清CER联合SCCA预测慢性肾功能衰竭患者病情进展的AUC为0.925,明显大于GFR的0.620（P＜0.05）。结论：血清CER、SCCA水平与慢性肾功能衰竭患者肾功能呈负相关,联合预测病情进展效能较好,值得临床予以重视应用。