草地贪夜蛾幼虫对四种刺激物质的味觉感受和取食选择

【目的】为了筛选有效的草地贪夜蛾Spodoptera frugiperda幼虫取食激食素和抑制剂并探究其味觉感受机理,为生态防治草地贪夜蛾提供理论和实践上的依据。【方法】利用单感受器记录法测定草地贪夜蛾5龄第2天幼虫下颚外颚叶上中栓锥感器和侧栓锥感器对不同浓度的蔗糖、黑芥子苷、单宁酸和盐酸奎宁4种刺激物质的电生理反应,并采用二项叶碟法测定草地贪夜蛾幼虫对这些刺激物质的取食选择行为。【结果】草地贪夜蛾幼虫中栓锥感器和侧栓锥感器内均存在对蔗糖、黑芥子苷和单宁酸敏感的味觉受体神经元,但是神经元的活性随着刺激物的种类及浓度而变化。其中,两类感器内神经元对蔗糖和黑芥子苷的反应均呈现典型的浓度梯度反应。中栓锥感器内存在对盐酸奎宁敏感的味觉受体神经元,但是呈现逆浓度梯度的反应模式,侧栓锥感器内不存在对盐酸奎宁敏感的神经元。蔗糖显著诱导幼虫的取食行为,而盐酸奎宁、黑芥子苷和单宁酸均抑制幼虫的取食行为,且都呈现浓度梯度的抑制活性。【结论】草地贪夜蛾幼虫中栓锥感器和侧栓锥感器内均存在对取食激食素和抑制剂敏感的味觉受体神经元,但是两类感器不论在反应谱上还是敏感性上均存在差异。蔗糖可以作为取食激食素,盐酸奎宁、黑芥子苷和单宁酸可以作为取食抑制剂的有效候选物质。幼虫对蔗糖、黑芥子苷和单宁酸的味觉反应在一定程度上解释了其取食选择行为的味觉基础。本研究为草地贪夜蛾的生态防治提供了味觉信息。

Expression of human chorionic gonadotropin, CD44v6 and CD44v4/5 in esophageal squamous cell carcinoma

AIM： To study the relationship between the expression of human chorionic gonadotropin （HCG）, CD44v6, CD44v4/5 and the infiltration, metastasis of esophageal squamous cell carcinoma. METHODS： By labeled streptavidin-biotin technique, the expressions of HCG, CD44v6, and CD44v4/5 in 42 patients with esophageal squamous cell carcinoma were examined. RESULTS： The positive rate of HCG expression in patients with lymph node metastasis was 85.71% （18/21）, higher than that （57.14%, 12/21） in those without lymph node metastasis （P〈0.05）. The positive rate of CD44v6 expression was 71.43% （15/21） in lymph node metastasis group, and 38.09% （8/21） in nonmetastasis group; there was a significant difference between the two groups （P〈0.05）. The positive rate of CD44v4/5 expression was 76.19% （16/21） in lymph node metastasis group, and 42.86% （9/21） in non-metastasis group; there was also a significant difference between them （P〈0.05）. From grade Ⅰ to grade Ⅲ in differentiation, the positive rate of HCG expression was 84.62% （11/13）, 70.59% （12/17） and 58.33% （7/12）, respectively, there was no significant difference among them （P〉0.05）. The positive rate of CD44v6 expression in grades Ⅰ-Ⅲ of cancer tissues was 76.92% （10/13）, 52.94% （9/17）, and 33.33% （4/12） respectively; there was no significant difference among them. The positive rate of CD44v4/5 expression in grades Ⅰ-Ⅲ of cancer tissues was 69.23% （9/13）, 64.71% （11/17）, and 41.67% （5/12） respectively; there was no significant difference among the three groups. There was no correlation between the positive rates of HCG and CD44v6, CD44v4/5 expression. Cancer cells in carcinomatous emboli and those infiltrating into vascular wall strongly expressed HCG, CD44v6, and CD44v4/5. CONCLUSION： Expression of HCG, CD44v6, and CD44v4/5 in esophageal squamous cell carcinoma is related to its infiltration and metastasis. HCG, CD44v6, and CD44v4/5 have different effects on the infiltration and metastasis of esophageal squamous cell carcinoma.

Low circulating levels of gastrin-17 in patients with Barrett's esophagus

AIM: To examine whether the fasting levels of serum gastrin-17 (G-17) are lower in Barrett's esophagus (BE)patients than in non-Barrett controls.METHODS: Nineteen patients with BE (presenting with a tubular segment ≥2 cm long in lower esophagus and intestinal metaplasia of incomplete type ('specialized columnar epithelium') in endoscopic biopsies from the tubular segment below the squamocolumnar junction were collected prospectively from outpatients referred to diagnostic gastroscopy. The controls comprised 199 prospectively collected dyspeptic outpatients without BE or any endoscopically visible lesions in the upper GI tract.Fasting levels of serum G-17 (G-17fast) were assayed with an EIA test using a Mab highly specific to amidated G-17. None of the patients and controls received therapy with PPIs or other antisecretory agents.RESULTS: The mean and median levels of G-17fast in serum were significantly lower (P = 0.001) in BE patients than in controls. The positive likelihood ratios (LR+) of low G-17fast to predict BE in the whole study population at G-17fast levels ＜0.5, ＜1, or ＜1.5 pmol/L were 3.5, 3.0,and 2.8, respectively. Among patients and controls with healthy stomach mucosa, the LR+ were 5.6, 3.8, and 2.6,respectively. In the whole study population, serum G-17 was below 2 pmol/L in 15 of 19 BE patients (79%). The corresponding prevalence was 66 of 199 (33%) in controls (P＜0.001). The G-17fast was 5 pmol/L or more in only one of the 19 BE patients (5%). In controls, 76 of the 199 patients (38%) had such high serum G-17fast levels (P＜0.01).CONCLUSION: Serum levels of G-17fast tend to be lower in native patients with BE than in healthy controls.

Estrogen,male dominance and esophageal adenocarcinoma:Is there a link?

Esophageal adenocarcinoma is a cancer with poor prognosis, and its incidence has risen sharply over recent decades. Obesity is a major risk factor for developing this cancer and there is a clear male gender bias in the incidence that cannot be fully explained by known risk factors. It is possible that a difference in the expression of estrogen, or its signaling axes, may contribute to this gender bias. We undertook a com- prehensive literature search and analyzed the available data regarding estrogen and estrogen receptor expres- sion, and the possible sex-specific links with esopha- geal adenocarcinoma development. Potentially relevant associations between visceral vs subcutaneous fat deposition and estrogen expression, and the effect of crosstalk between estrogen and leptin signaling were identified. We also found limited studies suggesting a role for estrogen receptor 13 expression in esophageal adenocarcinoma development. The current literature supports speculation on an etiological role for estrogen in the male gender bias in esophageal adenocarcino- ma, but further studies are required.

Effect of exercise training intensity on adipose tissue hormone sensitive lipase gene expression in obese women under weight loss

Background:Hormone sensitive lipase(HSL) is an enzyme that regulates adipose tissue lipolysis and plays an important role in chronic exerciseinduced changes in adipose tissue metabolism.The purpose of this study was to determine whether aerobic exercise intensity influences abdominal adipose tissue HSL gene expression in obese women under weight loss. Methods:Thirty women(body mass index(BMI) = 33.0±0.7 kg/m^2,age = 58±1 years) completed one of three 20-week interventions: caloric restriction alone(CR only,n = 8),CR plus moderate-intensity exercise(CR + moderate-intensity,45%—50%heart rate reserve(HRR). 3 day/week,n = 9),or CR plus vigorous-intensity exercise(CR + vigorous-intensity,70%—75%HRR,3 day/week,n = 13).Each group had a similar prescribed energy deficit comprised of underfeeding alone(2800 kcal/week for CR only) or underfeeding(2400 kcal/week) plus exercise(400 kcal/week).Body composition and maximal aerobic capacity(VO_2max) were measured,and subcutaneous abdominal adipose tissue samples were collected before and after the interventions.Adipose tissue HSL gene expression was measured by real time reversetranscriptase polymerase chain reaction. Results:All three interventions reduced body weight,fat mass,percent fat.and waist to a similar degree(all p < 0.01).In addition,all interventions did not change absolute VO_2 max,but increased relative VO_2 max(p < 0.05 to P < 0.01).Compared to pre-intervention.neither CR only nor CR + moderate-intensity changed adipose tissue HSL gene expression,but CR + vigorous-intensity significantly increased adipose tissue HSL gene expression(p < 0.01).The changes of HSL gene expression levels in the CR + vigorous-intensity group were significantly different from those in the CR only(p < 0.05) and CR + moderate-intensity(p < 0.01) groups.In the whole cohort,changes in adipose tissue HSL gene expression correlated positively to changes in absolute(r = 0.55,p < 0.01) and relative(r = 0.32,p = 0.09) VO_2 max. Conclusion:These results support a potential effect of aerobic exercise training intensity on hormone sensitive lipase pathway in adipose tissue metabolism in obese women under weight loss.

Temperature-dependent THz vibrational spectra of clenbuterol hydrochloride

Using the high-resolution Terahertz Time-domain spectroscopy (THz-TDS) and the standard sample pellet technique, the far-infrared vibrational spectra of clenbuterol hydrochloride (CH), a 2 -adrenergic agonist for decreasing fat deposition and enhancing protein accretion, were measured in temperature range of 77-295 K. Between 0.2 and 3.6 THz (6.6-120.0 cm-1 ), seven highly resolved spectral features, strong line-narrowing and a frequency blue-shift were observed with cooling. However, ractopamine hydrochloride, with some structural and pharmacological similarities to clenbuterol hydrochloride, showed no spectral features, indicating high sensitivity and strong specificity of THz-TDS. These results could be used for the rapid and nondestructive CH residual detection in food safety control.