牛乳酪蛋白源抗菌肽的研究进展

抗菌肽是具有抗菌活性的肽类物质的总称。除了广泛存在于生物体内的内源性抗菌肽外,已从酪蛋白的酶解产物中获得了多种外源性抗菌肽。抗菌肽的抗菌机理独特,有望成为新一代抗菌剂。简要综述了牛乳酪蛋白源抗菌肽的种类、抗菌机理及其研究展望。     

Availability of and access to critical habitats in regulated rivers: effects of low-head barriers on threatened lampreys

1.  Conservation of freshwater animal populations requires their access to, as well as sufficient availability of, critical habitats, such as those for reproduction. Abundant small-scale barriers may cause extensive fragmentation of freshwater habitat but, by comparison to larger structures their effects are rarely considered by catchment managers. The relationship between the distribution of, and access to, spawning habitat in a regulated river, characterized by abundant small barriers, was examined for river lamprey Lampetra fluviatilis , a threatened migratory fish.
2.  Telemetry of adult lamprey in the River Derwent, North East England was used to quantify upriver migration and access to spawning habitat, together with surveys of spawning habitat availability and spawning activity between 2002 and 2007.
3.  Access in to the Derwent appeared severely restricted by a tidal barrage, beyond which lamprey migrated rapidly in unobstructed reaches. Of all lamprey tagged in the lower 4 km of river, or ascending the barrage, 64% and 17% passed the first and second weirs respectively, with high flows crucial for this. Although over 98% of lamprey spawning habitat occurred more than 51 km upstream, on average just 1.8% of river lamprey spawners were recorded there.
4.  In order to protect or rehabilitate species or species assemblages, greater attention needs to be paid to the relative spatial distribution of low-head barriers and the resultant availability of key habitats within individual catchments. This is particularly important given the renewed emphasis internationally on low-head hydropower solutions as a source of renewable energy, and the rapid growth in numbers of low-head barriers in many catchments.     

热休克蛋白70在原发性高血压中的表达及其与炎症因子和血压的关系

目的:探讨原发性高血压患者热休克蛋白70(HSP-70)的表达水平,并分析其与炎症因子、血压的关系。方法:选择2017年3月至2019年3月我院收治的原发性高血压患者84例作为研究组,根据患者血压水平分为Ⅰ级组25例,Ⅱ级组37例和Ⅲ级组22例,另选同期体检健康者60例作为对照组,应用逆转录聚合酶链式反应(RT-PCR)检测各组血HSP70 m RNA水平,应用双抗体酶联免疫吸附法检测各组血清HSP-70、白细胞介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)和C反应蛋白(CRP)水平,比较各组血HSP70 m RNA、血清HSP70、IL-6、TNF-α和CRP水平,并分析相关性。结果:研究组血HSP-70mRNA相对表达量高于对照组(P0.05)。随高血压分级的升高各组患者血HSP-70mRNA相对表达量呈升高趋势,各组血HSP-70mRNA水平比较有统计学差异(P0.05)。研究组血清HSP-70、IL-6、TNF-α和CRP水平均高于对照组(P0.05)。随高血压分级的升高,各组患者血清HSP-70、IL-6、TNF-α和CRP水平呈升高趋势,不同组别血清HSP-70、IL-6、TNF-α和CRP水平比较有统计学差异(P0.05)。经Pearson相关分析显示,高血压患者血HSP-70 m RNA、HSP-70、IL-6、TNF-α和CRP水平与血压呈正相关(P0.05),血HSP-70 m RNA与IL-6、TNF-α和CRP水平呈正相关(P0.05),血清HSP-70与IL-6、TNF-α和CRP呈正相关(P0.05)。结论:高血压患者HSP-70和炎症因子异常升高,HSP-70与炎症因子水平和血压相关,提示HSP-70在高血压发生、发展中起到关键作用。     

Chemopreventive and renal protective effects for docosahexaenoic acid (DHA): implications of CRP and lipid peroxides

Background

The fish oil-derived ω-3 fatty acids, like docosahexanoic (DHA), claim a plethora of health benefits. We currently evaluated the antitumor effects of DHA, alone or in combination with cisplatin (CP) in the EAC solid tumor mice model, and monitored concomitant changes in serum levels of C-reactive protein (CRP), lipid peroxidation (measured as malondialdehyde; MDA) and leukocytic count (LC). Further, we verified the capacity of DHA to ameliorate the lethal, CP-induced nephrotoxicity in rats and the molecular mechanisms involved therein.

Results

EAC-bearing mice exhibited markedly elevated LC (2-fold), CRP (11-fold) and MDA levels (2.7-fold). DHA (125, 250 mg/kg) elicited significant, dose-dependent reductions in tumor size (38%, 79%; respectively), as well as in LC, CRP and MDA levels. These effects for CP were appreciably lower than those of DHA (250 mg/kg). Interestingly, DHA (125 mg/kg) markedly enhanced the chemopreventive effects of CP and boosted its ability to reduce serum CRP and MDA levels. Correlation studies revealed a high degree of positive association between tumor growth and each of CRP (r = 0.85) and leukocytosis (r = 0.89), thus attesting to a diagnostic/prognostic role for CRP. On the other hand, a single CP dose (10 mg/kg) induced nephrotoxicity in rats that was evidenced by proteinuria, deterioration of glomerular filtration rate (GFR, -4-fold), a rise in serum creatinine/urea levels (2–5-fold) after 4 days, and globally-induced animal fatalities after 7 days. Kidney-homogenates from CP-treated rats displayed significantly elevated MDA- and TNF-α-, but reduced GSH-, levels. Rats treated with DHA (250 mg/kg, but not 125 mg/kg) survived the lethal effects of CP, and showed a significant recovery of GFR; while their homogenates had markedly-reduced MDA- and TNF-α-, but -increased GSH-levels. Significant association was detected between creatinine level and those of MDA (r = 0.81), TNF-α ) r = 0.92) and GSH (r = -0.82); implying causal relationships.

Conclusion

DHA elicited prominent chemopreventive effects on its own, and appreciably augmented those of CP as well. The extent of tumor progression in various mouse groups was highly reflected by CRP levels (thus implying a diagnostic/prognostic role for CRP). Further, this study is the first to reveal that DHA can obliterate the lethal CP-induced nephrotoxicity and renal tissue injury. At the molecular level, DHA appears to act by reducing leukocytosis, systemic inflammation, and oxidative stress.     

AROMA PROPERTIES AND THRESHOLDS OF SOME BRANCHED-CHAIN AND OTHER MINOR VOLATILE FATTY ACIDS OCCURRING IN MILKFAT AND MEAT LIPIDS1

Aroma properties of twenty-three branched-chain, odd-numbered, or unsaturated fatty acids which had each been dispersed in acidic aqueous media (pH 2.0) were evaluated. Aroma threshold values were determined using approximately 95 judges for assessing the presence of aromas over dilutions of each fatty acid. Qualitative aroma threshold values for individual fatty acids ranged from 0.006 to 82.4 ppm in the acidic solutions, and 4-ethyloctanoic acid exhibited the lowest threshold of the group tested. Qualitative aroma assessments of dilutions of each fatty acid showed a wide range of unique aroma properties. Fatty acids exhibiting branching at the 4-position had goaty/muttony/sheepy aroma notes as did other fatty acids containing 8-carbon chain structures. Cheese-like aromas were associated with the shorter branched-chain fatty acids.     

Circumpolar dynamics of a marine top‐predator track ocean warming rates

Global warming is a nonlinear process, and temperature may increase in a stepwise manner. Periods of abrupt warming can trigger persistent changes in the state of ecosystems, also called regime shifts. The responses of organisms to abrupt warming and associated regime shifts can be unlike responses to periods of slow or moderate change. Understanding of nonlinearity in the biological responses to climate warming is needed to assess the consequences of ongoing climate change. Here, we demonstrate that the population dynamics of a long‐lived, wide‐ranging marine predator are associated with changes in the rate of ocean warming. Data from 556 colonies of black‐legged kittiwakes Rissa tridactyla distributed throughout its breeding range revealed that an abrupt warming of sea‐surface temperature in the 1990s coincided with steep kittiwake population decline. Periods of moderate warming in sea temperatures did not seem to affect kittiwake dynamics. The rapid warming observed in the 1990s may have driven large‐scale, circumpolar marine ecosystem shifts that strongly affected kittiwakes through bottom‐up effects. Our study sheds light on the nonlinear response of a circumpolar seabird to large‐scale changes in oceanographic conditions and indicates that marine top predators may be more sensitive to the rate of ocean warming rather than to warming itself.     

RevSex duplication-induced and sex-related differences in the SOX9 regulatory region chromatin landscape in human fibroblasts

It was recently shown that duplications of the RevSex element, located 0.5 Mb upstream of SOX9, cause XX-disorder of sex development (DSD), and that deletions cause XY-DSD. To explore how a 148 kb RevSex duplication could have turned on gonadal SOX9 expression in the absence of SRY in an XX-male, we examined the chromatin landscape in primary skin fibroblast cultures from the index, his RevSex duplication-carrier father and six controls. The ENCODE project supports the notion that chromatin state maps show overlap between different cell types, i.e., that our study of fibroblasts could be of biological relevance. We examined the SOX9 regulatory region by high-resolution ChIP-on-chip experiments (a kind of “chromatin-CGH”) and DNA methylation investigations. The RevSex duplication was associated with chromatin changes predicting better accessibility of the SRY-responsive TESCO enhancer region 14–15 kb upstream of SOX9. Four kb downstream of the TESCO evolutionary conserved region, a peak of the enhancer/promoter-associated H3K4me3 mark was found together with a major dip of the repressive H3K9me3 chromatin mark. Similar differences were also found when three control males were compared with three control females. A marked male/female difference was a more open chromatin signature in males starting ~400 kb upstream of SOX9 and increasing toward the SOX9 promoter. In the RevSex duplication-carrier father, two positions of DNA hypomethylation were also found, one corresponding to the H3K4me3 peak mentioned above. Our results suggest that the RevSex duplication could operate by inducing long-range epigenetic changes. Furthermore, the differences in chromatin state maps between males and females suggest that the Y chromosome or X chromosome dosage may affect chromatin conformation, i.e., that sex-dependent gene regulation may take place by chromatin modification.