Design and Synthesis of Analogues of Marine Natural Product Galaxamide,an N-methylated Cyclic Pentapeptide,as Potential Anti-Tumor Agent in Vitro

Herein, we report design and synthesis of novel 26 galaxamide analogues with N-methylated cyclo-pentapeptide, and their in vitro anti-tumor activity towards the panel of human tumor cell line, such as, A549, A549/DPP, HepG2 and SMMC-7721 using MTT assay. We have also investigated the effect of galaxamide and its representative analogues on growth, cell-cycle phases, and induction of apoptosis in SMMC-7721 cells in vitro. Reckon with the significance of conformational space and N-Me aminoacid (aa) comprising this compound template, we designed the analogues with modification in N-Me-aa position, change in aa configuration from l to d aa and substitute one Leu-aa to d/l Phe-aa residue with respective to the parent structure. The efficient solid phase parallel synthesis approach is employed for the linear pentapeptide residue containing N-Me aa, followed by solution phase macrocyclisation to afford target cyclo pentapeptide compounds. In the present study, all galaxamide analogues exhibited growth inhibition in A549, A549/DPP, SMMC-7721 and HepG2 cell lines. Compounds 6, 18, and 22 exhibited interesting activities towards all cell line tested, while Compounds 1, 4, 15, and 22 showed strong activity towards SMMC-7221 cell line in the range of 1–2 μg/mL IC₅₀. Flow cytometry experiment revealed that galaxamide analogues namely Compounds 6, 18, and 22 induced concentration dependent SMMC-7721 cell apoptosis after 48 h. These compounds induced G0/G1 phase cell-cycle arrest and morphological changes indicating induction of apoptosis. Thus, findings of our study suggest that the galaxamide and its analogues 6, 18 and 22 exerted growth inhibitory effect on SMMC-7721 cells by arresting the cell cycle in the G0/G1 phase and inducing apoptosis. Compound 1 showed promising anti-tumor activity towards SMMC-7721 cancer cell line, which is 9 and 10 fold higher than galaxamide and reference DPP (cisplatin), respectively.     

北京都市型现代循环农业发展实践探索

从分析北京发展都市型现代循环农业的意义入手,分析了北京都市型现代循环农业价值链理论、北京都市型现代循环农业的发展模式,最后提出了促进北京都市型现代循环农业发展应构建三大支撑体系的建议.     

Biochemical and pharmacological characterization of adenosine A1 receptors in eel (Anguilla anguilla) brain

N⁶-cyclohexyl[³H]adenosine ([³H]CHA) was used to label adenosine A1 receptors in membranes prepared from male and female eel whole brain. The A1 receptor agonist [³H]CHA bound saturably, reversibly and with high affinity (K_d = 0.91 ± 0.12 nM; B_max = 120.36 ± 5.2 fmol mg⁻¹ protein). In equilibrium competition experiments, the adenosine agonists and antagonists all displaced [³H]CHA from high-affinity binding sites with the rank order of potency in displacing, characteristics of an A1 adenosine receptor. Mg²⁺ dramatically increased the affinity of [³H]CHA without modifying the maximal binding capacity. The specific binding was inhibited by guanosine 5′-triphosphate (K_i = 2.54 ± 0.98 μM). The [³H]CHA binding sites are ubiquitously distributed with a maximum in cerebellum and a minimum in olfactory bulb. No difference was observed between male and female brain. In eel brain, synaptosomes (P2), stimulation of adenosine 3′,5′-monophosphate (cyclic AMP) accumulation with 10⁻⁵ M forskolin was markedly reduced (45.5%) by treatment with the adenosine A1 receptor agonist CHA (10⁻⁴ M), and the reduction was reversed in presence of the selective A1 receptor antagonist 8-cyclopentyltheophylline (10⁻⁵ M). In superfused eel cerebellar synaptosomes, K⁺ stimulated the release of adenosine in a partially Ca²⁺-dependent manner. The findings, taken together, suggest the hypothesis that adenosine A1 receptors present in eel brain could modulate synaptic transmission, as A1 receptors do in other vertebrates.     

Utilizing wild Fragaria virginiana in strawberry cultivar development: Inheritance of photoperiod sensitivity, fruit size, gender, female fertility and disease resistance

The genetics of photoperiod sensitivity, flowering date, fruit size, gender, female fertility, and disease resistance were investigated in progeny between sets of elite F. virginiana selections and F. × ananassa cultivars and selections planted at sites in Michigan, Minnesota and Ontario. Progeny means varied considerably for all the production traits. Most notable were the large fruit and high fertility observed in crosses with High Falls 22 at all three sites, and Montreal River 10 in Ontario and Michigan. Fragaria virginiana ssp. virginiana parents yielded progeny with much larger fruit than F. virginianassp. glauca parents. General combining ability was significant for all traits at all locations, while specific combining ability was significant for only fruit diameter, ovule set and fruit set in Michigan. Overall, the highest number of day-neutral genotypes were detected in Ontario (mean =44%) compared to Minnesota (31%) and Michigan (26%). In progeny populations of day-neutral F. × ananassa × short-day F. virginiana almost all fit the 1:1 ratio expected if day-neutrality is regulated by a single dominant gene; however, only a few families of short-day F. × ananassa ×day-neutral F. virginianacrosses fit a 1:1 ratio. Likewise, in progeny of day-neutral F. virginiana ×day-neutral F × ananassa crosses, only a few of them fit the 3:1 ratio expected if day-neutrality is regulated by a single dominant gene. These data suggest that it should be relatively easy to useF. virginiana germplasm in strawberry cultivar improvement, and that several different sources of day-neutrality may exist in natural populations. This revised version was published online in August 2006 with corrections to the Cover Date.     

Secondary somatic embryogenesis and applications in plant breeding

Summary Secondary somatic embryogenesis is the phenomenon whereby new somatic embryos are initiated from somatic embryos. Such cultures have been described in at least 80 Gymnosperm and Angiosperm species. In the initial step (primary somatic embryogenesis) such cultures have to be started from plant explants. In general, primary somatic embryogenesis from vegetative plant explants is, indirect and mostly driven by auxin (AUX) or auxin and cytokinin (AUX/CYT) supplemented media, whereas, from zygotic embryos it is direct and driven, to a larger extent, by CYT or growth regulator free media. Primary somatic embryogenesis from floral plant explants is between these two extremes. Indirect and direct somatic embryogenesis should be seen as two extremes of one continuum: in indirect somatic embryogenesis the embryos develop up to the (pre)-globular stage and in direct somatic embryogenesis to mature stages before they are subjected to secondary embryogenesis. In general, secondary embryogenesis requires no growth regulators in species with CYT driven primary embryogenesis. Whereas, continuous exposure to growth regulators is needed in species with CYT/AUX or AUX driven primary embryogenesis.In most species somatic embryos can be converted into shoots, although the frequencies are mostly low. In general, somatic embryos induced by growth regulator free or CYT supplemented media meet more difficulties in shoot development than embryos induced by AUX supplemented media. Applications of secondary somatic embryogenesis for plant breeding are discussed.     

紫海胆肠道放线菌Micromonospora sp. HDa2次生代谢产物的研究

采用常规色谱分离技术对分离自健康紫海胆肠道的稀有放线菌Micromonospora sp. HDa2发酵液的化学成分进行分离纯化,并以波谱技术确定化合物的结构。结果表明：从放线菌Micromonospora sp. HDa2的发酵液乙酸乙酯提取物中分离鉴定了6个已知结构的环二肽化合物,分别为环(苯丙-缬)二肽(1)、环(苯丙-亮)二肽(2)、环(苯丙-异亮)二肽(3)、环(苯丙-苯丙)二肽(4)、环(亮-亮)二肽(5)和环(亮-异亮)二肽(6)。对紫海胆肠道放线菌进行分离,结果发现以上化合物均是从Micromonospora属放线菌中发现的。     

Marine Nucleosides: Structure,Bioactivity, Synthesis and Biosynthesis

Nucleosides are glycosylamines that structurally form part of nucleotide molecules, the building block of DNA and RNA. Both nucleosides and nucleotides are vital components of all living cells and involved in several key biological processes. Some of these nucleosides have been obtained from a variety of marine resources. Because of the biological importance of these compounds, this review covers 68 marine originated nucleosides and their synthetic analogs published up to June 2014. The review will focus on the structures, bioactivities, synthesis and biosynthetic processes of these compounds.     

Alternative Methods for the Detection of Emerging Marine Toxins: Biosensors,Biochemical Assays and Cell-Based Assays

The emergence of marine toxins in water and seafood may have a considerable impact on public health. Although the tendency in Europe is to consolidate, when possible, official reference methods based on instrumental analysis, the development of alternative or complementary methods providing functional or toxicological information may provide advantages in terms of risk identification, but also low cost, simplicity, ease of use and high-throughput analysis. This article gives an overview of the immunoassays, cell-based assays, receptor-binding assays and biosensors that have been developed for the screening and quantification of emerging marine toxins: palytoxins, ciguatoxins, cyclic imines and tetrodotoxins. Their advantages and limitations are discussed, as well as their possible integration in research and monitoring programs.