降脂蛋白(a)研究

脂蛋白(a)[Lp(a)]是由载脂蛋白(a)(apo(a))与载脂蛋白B100(apoB100)通过共价键连接的脂蛋白。高血浆水平Lp(a)是心血管疾病的独立风险因子,Lp(a)的血浆水平主要受遗传因素调控,主要有LPA[lipoprotein,Lp(a)]基因的三环结构域kringle IV/2拷贝数和单核苷酸多态性(SNP)。欧洲动脉粥样硬化协会(EAS)和美国心脏病协会(AHA)建议对于高Lp(a)的人群应当考虑降高Lp(a)的治疗。目前已有多种降高Lp(a)的药物和方法,如血浆分离置换法、雌激素治疗、反义核苷酸治疗、类法尼醇X核内受体(farnesoid X receptor,FXR)激动治疗等,但应用于临床的降高Lp(a)的药物和方法依然缺乏。本文拟就降Lp(a)的药物和方法进展情况进行综述。     

脂蛋白(a)合成的调节

脂蛋白(a) ［ LP(a)］是一种与低密度脂蛋白(LDL)结构极其相似的脂蛋白,它由LDL脂质核心、载脂蛋白B100(apoB100)及特异性的成分载脂蛋白(a)［ apo(a)］组成. 大量的研究表明,高LP(a)是动脉粥样硬化独立的危险因素.而LP(a)在血浆中的水平及致病能力取决于其合成的速率及其颗粒的大小. 因此, 如何抑制LP(a)合成,进而从源头减少LP(a) 的血浆水平,对动脉粥样硬化的防治具有重要的意义.本文就当前关于影响LP(a)合成的环节及相关机制进行综述, 从而为降LP(a)药物的研究提供新的视角.     

What Is (Not) a Baboon?

The term “baboon” is the common name used for a subset of terrestrial Cercopithecines with large bodies and protruding snouts. Although the application of the term has changed considerably over the years, we argue that common names, such as “baboon,” should reflect the current state of phylogenetic knowledge. This practice promotes a broader understanding of taxonomic diversity that can impact decisions related to ecotourism, wildlife management, and conservation. Thus, we argue that “baboon” should be used only for members of the genus Papio.     

Ecological requirements of Ostracoda (Crustacea) in a heavily polluted shallow lake,Lake Yeniçağa (Bolu,Turkey)

Although the area of Lake Yeniça?a is a potential candidate for RAMSAR convention, several anthropogenic factors compromise its biological diversity. This is mostly due to nutrient-rich water released from both point and nonpoint sources. Thirteen ostracod taxa (Candona neglecta, C. candida, Ilyocypris bradyi, Darwinula stevensoni, Cypridopsis vidua, Physocypria kraepelini, Cypria ophtalmica, Prionocypris zenkeri, Eucypris virens, Herpetocypris reptans, Pseudocandona compressa, Fabaeformiscandona fabaeformis Potamocypris cf. fulva) were found during this study. Potamocypris cf. fulva is a new record for the Turkish freshwater ostracod fauna. The first nine of these species have broad geographic ranges, implying high tolerance levels to different environmental variables. Based on the estimated species optima and tolerance levels, two species exhibited higher effective number of occurrences (C. neglecta, and D. stevensoni, respectively) than the other species. Three species (C. neglecta, D. stevensoni, I. bradyi) did not show significant correlation with any environmental variable we used. Both Canonical correspondence (CCA) and Pearson correlation analyses showed that temperature was the most effective predictor of species occurrence, followed by electrical conductivity and redox potential. In contrast, pH and dissolved oxygen of water were the least effective predictors. Approximately 71% of the correlation between community composition and environmental variables was explained by the first axis of the CCA diagram, which had a relatively low (7.7%) cumulative variance of species. The lower (560 μg/l) and the upper (2030 μg/l) levels of ammonia (NH₃) exceeded the limits during winter season. The concentrations of total coliform and Escherichia coli bacteria were measured up to 10 × 10⁷ cfu/ml and 10 × 10³ cfu/ml, respectively. Results of physicochemical measurements, microbiological counts, and species data indicate that water quality of Lake Yeniça?a has been rapidly deteriorated by anthropogenic factors that are the main threat for not only the lake’s aquatic diversity but also human health around the lake.     

Congenital absence of a tail in a Reeves‘ muntjac (Muntiacus reevesi)

Two abnormalities of the tail have been observed in Reeves muntjac. A male was born acaudate and an adult doe had a tail less than a third of the normal length. The range and mean of lengths of body and tail are given for animals over 2 years old.     

Dinophysis norvegica (Dinophyceae), more a predator than a producer?

Several studies have proved that some Dinophysis species are capable of ingesting particulate organic matter besides of being photosynthetic, a form of nutrition termed mixotrophy. Phagotrophy may be an important aspect of the life history of the genus Dinophysis and the key to understand its ecology. We used modern techniques coupling flow cytometry and acidotropic probes to detect and score food vacuolated Dinophysis norvegica cells in natural samples. In addition, feeding experiments were conduced under controlled conditions to observe if D. norvegica would grow feeding on the cryptophyte Teleaulax amphioxeia. The results of the field observations showed a frequency of phagotrophy between 25 and 71% in a natural D. norvegica population from the Baltic Sea, which is higher than previous reports (1–20%). Although molecular methods have proved that the kleptoplastids of the D. norvegica from the Baltic Sea are from T. amphioxeia, the laboratory experiments showed that the presence of T. amphioxeia in the cultures did not enhance the survival rate of D. norvegica neither in phototrophic nor in heterotrophic conditions. We suggest that the D. norvegica Kleptoplats are obtained through a heterotrophic or mixotrophic protist, which have been feeding on cryptophytes, as it has recently been shown for Dinophysis acuminata. Our main conclusion is that D. norvegica, and probably all other species from the genus Dinophysis, is mainly phagotrophic and feeds on a larger prey than T. amphioxeia. Autotrophy through kleptoplastidy would be a secondary feature used as a complementary or short-term survival strategy.     

Towards a tunable molecular memory that fits into a (10 Å)3 cube

Using DFT calculations we predict a novel family of small amino acid-based memory-exhibiting molecules, namely complexes of triply deprotonated cysteine (or its derivatives) with selected hexavalent transition metals. We show that the energy difference of the 0 and 1 electromers--corresponding to two chemically distinct oxidation states of a metal, M(VI) and M(IV)--can be tuned towards the thermodynamic equilibrium via deliberate chemical substitutions in the cysteine ligand. Although the thermal stability of both electromers is computed to be rather small at ambient temperatures (due to facile interchange of states 0 and 1 via a low-lying M(V) configuration), we hope to improve stability in related systems. [Figure: see text]. We propose novel kind of tunable molecular memory, based on intramolecular 2e- redox reaction.     

The dynamics of a population of roach (Rutilus rutilus (L.)) in a shallow lake: is there a 2-year cycle in recruitment?

Recruitment success of roach varied dramatically between 1978 and 1985 in Alderfen Broad, a small lake in eastern England. All size classes of roach feed to a significant extent upon zooplankton, but the underyearling fish have the greatest effects upon the abundance, species composition and mean size of zooplankton. During years of good recruitment (1979, 1981, 1983 and 1985) when the 0 + age group was abundant, they showed poor growth as a result of the depression of their prey populations. Older fish also tended to grow poorly in these years and may have been less fecund the following year. In years of poor recruitment (1980, 1982 and 1984), with the release of the depressive effect upon the zooplankton exerted by underyearling fish, the older size classes tended to grow well with higher fecundity the following season, giving rise to good recruitment of underyearling fish, even when the number of spawners was low. The evidence indicates that there is a 2-year cycle of roach recruitment in Alderfen and this will be described.     

Lipoprotein(a): still an enigma?

PURPOSE OF REVIEW: Lipoprotein(a) belongs to the class of the most atherogenic lipoproteins. Despite intensive research - in the last year more than 80 papers have been published on this topic - information is still lacking on the physiological function of lipoprotein(a) and the site of its catabolism. Important advances have been made in the knowledge of these points, which may have some therapeutic implications. RECENT FINDINGS: The association of high lipoprotein(a) values with an increase in risk for coronary events has been documented in further prospective studies. This increased risk may relate to recent findings that apolipoprotein(a) is produced in situ within the vessel wall. In addition, lipoprotein(a) binds and inactivates the tissue factor pathway inhibitor and induces plasminogen activator inhibitor type 2 expression in monocytes. A new antisense oligonucleotide strategy has been proposed which efficiently inhibits apolipoprotein(a) expression in vitro and in vivo. Apolipoprotein(a), however, suppresses angiogenesis and thus may interfere with the infiltration of tumor cells. Finally, the enzymatic activity leading to the formation of apolipoprotein(a) fragments in plasma and their catabolism have been further elucidated. SUMMARY: We are still far away from understanding the pathways involved in lipoprotein(a) catabolism, and the physiological function of this lipoprotein. Recent findings, however, provide new insight into pathomechanisms in patients with increased lipoprotein(a) related to hemostasis, which may serve as a basis for designing new treatment strategies.     

Litter in a first–order stream of a temperate deciduous forest (Margaraça Forest, central Portugal)

To evaluate the importance and fate of organic matter inputs in forested streams, we determined the litterfall inputs and the benthic coarse particulate organic matter (CPOM) in one headwater stream flowing through a mixed deciduous forest, during one year. Both vertical traps and the stream bottom were sampled monthly. The material collected was sorted into four main categories: leaves, fruits and flowers, twigs and debris. Litter production was 715 g m−2 y−1 and seasonal, with 73% of the annual total during October–December (autumn). Leaves comprised the largest litter component. Benthic organic matter was 1880 g m−2 y−1, and was also seasonal. Highest accumulation was attained in spring, and twigs and branches comprised the major component. This revised version was published online in July 2006 with corrections to the Cover Date.     

Leptomonas jaculum (Leger, 1902) Woodcock 1914: a leptomonas or a blastocrithidia?

Flagellates Leptomonas jaculum, inhabiting the intestine of the water scorpion Nepa cinerea posses promastigote organization, typical of the genus Leptomonas. Nevertheless phylogenetic analysis of the 18S rRNA gene revealed that these trypanosomatids form a common phylogenetic clade with cyst-forming representatives of the genus Blastocrithidia. Morphological characters supporting the unity of the group Blastocrithidia + L. jaculum and the probability of including L. oncopelti in it are discussed.     

CNS stem cells: Where's the biology (a.k.a. beef)?

Central nervous system (CNS) stem cells have become the subject of many laboratories' efforts, presentations, and publications. Yet, in the stem cell world, CNS cells are viewed with skepticism. This is likely due to a dearth of biology (in vivo function) to accompany a flurry of phenomenological and restorative neurology studies. In this article, we compare and contrast the biological knowledge of adult forebrain epidermal growth factor-responsive neural stem cells that has emerged from our laboratories with that of hematopoietic stem cells, using two recent papers in the latter field as specific examples. A comparison of stem cell location, lineage, and repopulation suggests that our understanding of CNS stem cell biology is immature. We conclude that a greater focus on in vivo biology will enhance our knowledge and understanding of CNS stem cells. © 1998 John Wiley & Sons, Inc. J Neurobiol 36: 307–314, 1998     

Wide-range protein photo-crosslinking achieved by a genetically encoded N(ε)-(benzyloxycarbonyl)lysine derivative with a diazirinyl moiety

A derivative of N(ε)-benzyloxycarbonyl-L-lysine with a photo-reactive diazirinyl group, N(ε)-[((4-(3-(trifluoromethyl)-3H-diazirin-3-yl)benzyl)oxy)carbonyl]-L-lysine, was site-specifically incorporated into target proteins in mammalian cells. The incorporated photo-crosslinker is able to react not only with residues as distant as about 15 ? but also with those in closer proximity, thus enabling "wide-range" photo-crosslinking of proteins.