Molecular Networking-Guided Isolation of New Etzionin-Type Diketopiperazine Hydroxamates from the Persian Gulf Sponge Cliona celata

The Persian Gulf is a unique and biologically diverse marine environment dominated by invertebrates. In continuation of our research interest in the chemistry and biological activity of marine sponges from the Persian Gulf, we selected the excavating sponge Cliona celata for detailed metabolome analyses, in vitro bioactivity screening, and chemical isolation studies. A UPLC-MS/MS (MS²) molecular-networking-based dereplication strategy allowed annotation and structural prediction of various diketopiperazines (DKPs) and etzionin-type diketopiperazine hydroxamates (DKPHs) in the crude sponge extract. The molecular-networking-guided isolation approach applied to the crude extract afforded the DKPH etzionin (1) and its two new derivatives, clioetzionin A (2) and clioetzionin B (3). Another new modified DKP (4) was identified by MS/MS analyses but could not be isolated in sufficient quantities to confirm its structure. The chemical characterization of the purified DKPHs 1–3 was performed by a combination of 1D and 2D NMR spectroscopy, HRMS, HRMS/MS, and [α]_D analyses. Compounds 1 and 2 exhibited broad antibacterial, antifungal, and anticancer activities, with IC₅₀ values ranging from 19.6 to 159.1 µM. This is the first study investigating the chemical constituents of a C. celata specimen from the Persian Gulf. It is also the first report of full spectroscopic data of etzionin based on extensive spectroscopic analyses.     

Biogeography of pelagic food webs in the North Pacific

The tufted puffin (Fratercula cirrhata) is a generalist seabird that breeds throughout the North Pacific and eats more than 75 different prey species. Using puffins as samplers, we characterized the geographic variability in pelagic food webs across the subarctic North Pacific from the composition of ~10,000 tufted puffin meals (~56,000 prey items) collected at 35 colonies in the Gulf of Alaska (GoA) and Aleutian Archipelago. Cluster analysis of diet species composition suggested three distinct forage fish communities: (i) in the northern GoA, multiple age‐classes of coastal and shelf residents such as capelin, sand lance and herring dominated the food web, (ii) in the western GoA to eastern Aleutians, the shelf community was dominated by transient age‐0 walleye pollock, and (iii) in the western Aleutians, shelf‐edge and mesopelagic forage species such as squid, lanternfish, and Atka mackerel were prevalent. Geographic patterns of abundance of capelin and sand lance in tufted puffin diets were corroborated by independent research fisheries and diets of piscivorous fish, indicating that puffin diets reflect the local abundance of forage species, not just selection of favored species. Generalized additive models showed that habitat characteristics predict, in a non‐linear fashion, forage species distribution and abundance across two large marine ecosystems. We conclude that major biogeographic patterns in forage fish distribution follow gradients in key habitat features, and puffin diets reflect those patterns.     

我国北部湾部分海产品中副溶血弧菌的基因分型研究

利用RAPD技术对北部湾分离的24株Vp进行基因分型。结果显示：RAPD可以分离出7~11条不同的条带,大小0.45~1.50 kb。聚类分析结果表明在相似度为0.84时,RAPD分辨力指数为0.931。采用通过POPGENE 32软件对比了24株Vp的各种遗传参数,结果表明：RAPD的Shannon信息指数、有效等位基因数、Nei基因多样性分别为0.5616、1.6816和0.3823。表明RAPD能较好地研究Vp的分子遗传特征,适合于区分不同来源的Vp菌株。     

Transnational Ecosystem Services: The Potential of Habitat Conservation for Waterfowl Through Recreational Hunting Activities

This article explores transnational ecosystem services in North America, provided by winter habitat for waterfowl in western Mexico coastal lagoons, and the hunting industry supported by these birds in the United States. This article shows that the number of waterfowl harvested in the United States is related to the abundance of waterfowl wintering in Mexico. On average, this flow of ecosystem services annually yields US$ 4.68 million in hunting stamp sales in the western United States. A demand curve, fitted to duck hunting licenses as a function of stamp price and previous-year waterfowl harvest, estimated US$3–6 million in consumer surplus produced in addition to governmental stamp sales revenue. This strongly suggests that waterfowl wintering habitat in western Mexico is economically valuable to U.S. hunters. Because hunters may benefit substantially from these habitats they may be willing to pay for conservation efforts in western Mexico that can result in transnational benefits received in the United States.     

北部湾多齿蛇鲻雌雄群体组成、生长、死亡特征的差异

利用2006年6月~2008年11月从广西北海,广东江洪、企水,海南东方、三亚等五个港口底拖网和流刺网渔获物中随机采集的样本,对北部湾海域多齿蛇鲻雌、雄群体的组成、生长、死亡特性进行了比较。结果表明,多齿蛇鲻雌性个体大于雄性个体,雌性渔获群体叉长范围104.3~398.0 mm,平均叉长215.4±62.9 mm;体重范围8.0~809.0 g,平均体重121.2±122.8 g;雄性渔获群体叉长范围122.7~345.0 mm,平均叉长211.1±45.9 mm;体重范围13.3~434.5 g,平均体重101.1±72.6 g。雌、雄个体数量不平衡,全年各月渔获量中雌性个体均多于雄性个体,雌、雄性比约为1.79∶1,周年变化呈现一定的波动,各月性比波动于1.29∶1~3.68∶1;雌、雄个体的性腺发育基本同步,但雄性个体比雌性个体进入性成熟季节的时间稍早;雌、雄群体的生长特性差异明显,生长参数K值分别为0.44 a-1和0.53 a-1,体重生长拐点年龄分别为2.41和1.97;雌、雄群体的死亡特征也存在明显差异,总死亡系数分别为2.73和3.01,自然死亡系数分别为0.89和1.04。     

辽西海域日本对虾生产性移植放流试验

１９９８年５月 ２４～２９日，在辽宁省葫芦岛市连山湾近岸水域放流体长１０．６±１．１ｍｍ的日本对虾２ ７９８．８万尾。 ８月中旬～１０月中旬期间，沿岸作业的 ５３４只渔船兼捕到本种商品虾 ２４．５ ｔ，平均体长 １４７．３ｍｍ，平均体重 ４０．７ ｇ，相当于 ６０．３万尾，回捕率为 ２． １５％，放流投资与增殖虾产值的比例为 １：５．４，效果良好。     

Bottom-up forcing and the decline of Steller sea lions (Eumetopias jubatus) in Alaska: assessing the ocean climate hypothesis

Declines of Steller sea lion (Eumetopias jubatus) populations in the Aleutian Islands and Gulf of Alaska could be a consequence of physical oceanographic changes associated with the 1976–77 climate regime shift. Changes in ocean climate are hypothesized to have affected the quantity, quality, and accessibility of prey, which in turn may have affected the rates of birth and death of sea lions. Recent studies of the spatial and temporal variations in the ocean climate system of the North Pacific support this hypothesis. Ocean climate changes appear to have created adaptive opportunities for various species that are preyed upon by Steller sea lions at mid‐trophic levels. The east–west asymmetry of the oceanic response to climate forcing after 1976–77 is consistent with both the temporal aspect (populations decreased after the late 1970s) and the spatial aspect of the decline (western, but not eastern, sea lion populations decreased). These broad‐scale climate variations appear to be modulated by regionally sensitive biogeographic structures along the Aleutian Islands and Gulf of Alaska, which include a transition point from coastal to open‐ocean conditions at Samalga Pass westward along the Aleutian Islands. These transition points delineate distinct clusterings of different combinations of prey species, which are in turn correlated with differential population sizes and trajectories of Steller sea lions. Archaeological records spanning 4000 yr further indicate that sea lion populations have experienced major shifts in abundance in the past. Shifts in ocean climate are the most parsimonious underlying explanation for the broad suite of ecosystem changes that have been observed in the North Pacific Ocean in recent decades.     

Plankton populations at the bifurcation of the North Pacific Current

As the eastward‐flowing North Pacific Current approaches the North American continent it bifurcates into the southward‐flowing California Current and the northward‐flowing Alaska Current. This bifurcation occurs in the south‐eastern Gulf of Alaska and can vary in position. Dynamic height data from Project Argo floats have recently enabled the creation of surface circulation maps which show the likely position of the bifurcation; during 2002 it was relatively far north at ∼53°N then, during early 2003, it moved southwards to a more normal position at ∼45°N. Two ship‐of‐opportunity transects collecting plankton samples with a Continuous Plankton Recorder across the Gulf of Alaska were sampled seasonally during 2002 and 2003. Their position was dependent on the commercial ship’s operations; however, most transects sampled across the bifurcation. We show that the oceanic plankton differed in community composition according to the current system they occurred in during spring and fall of 2002 and 2003, although winter populations were more mixed. Displacement of the plankton communities could have impacts on the plankton’s reproduction and development if they use cues such as day length, and also on foraging of higher trophic‐level organisms that use particular regions of the ocean if the nutritional value of the communities is different. Although we identify some indicator taxa for the Alaska and California currents, functional differences in the plankton communities on either side of the bifurcation need to be better established to determine the impacts of bifurcation movement on the ecosystems of the north‐east Pacific.     

Trends in coho marine survival in relation to the regime concept

There was a synchronous and significant decrease in marine survival of coho salmon in the Strait of Georgia, Puget Sound, and off the coast from California to Washington after 1989. This large-scale, synchronous change indicates that trends in coho marine survivals were linked over the southern area of their distribution in the north-east Pacific, and that these linkages were associated with a common event. Indicators of large-scale climate change (the Aleutian Low Pressure Index) and of recent regional climate change (the April flows from the Fraser River) also changed abruptly about the same time. The synchrony of trends in marine survival of aggregates of coho stocks from three distinct marine areas and trends in climate indices implies that climate/ocean changes can have profound impacts on the population dynamics of coho salmon. The trend towards low marine survival may persist as long as the trends in the climate indicators do not change.     

Is observed variability in the long-term results of the Continuous Plankton Recorder survey a response to climate change?

In the more than 50 years that the Continuous Plankton Recorder (CPR) survey has operated on a regular monthly basis in the north-east Atlantic and North Sea, large changes have been witnessed in the planktonic ecosystem. These changes have taken the form of long-term trends in abundance for certain species or stepwise changes for others, and in many cases are correlated with a mode of climatic variability in the North Atlantic, either: (1) the North Atlantic Oscillation (NAO), a basin-scale atmospheric alteration of the pressure field between the Azores high pressure cell and the Icelandic Low; or (2) the Gulf Stream Index (GSI), which measures the latitudinal position of the north wall of the Gulf Stream. Recent work has shown that the changes in the GSI are coupled with the NAO and Pacific Southern Oscillation with a 2 year lag. The plankton variability is also possibly linked to changes observed in the distribution and flux of water masses in the surface, intermediate and deep waters of the North Atlantic. For example, in the last two decades, the extent and location of the formation of North Atlantic Deep Water, Labrador Sea Intermediate Water and Norwegian Sea intermediate and upper-layer water has altered considerably. This paper discusses the extent to which observed changes in plankton abundance and distribution may be linked to this basin-scale variability in hydrodynamics. The results are also placed within the context of global climate warming and the possible effects of the observed melting of Arctic permafrost and sea ice on the subpolar North Atlantic.