Body-size spectra of biofilm-dwelling protozoa and their seasonal shift in coastal ecosystems

Community-based assessment of protozoa is usually performed at a taxon-dependent resolution. As an inherent ‘taxon-free’ trait, however, body-size spectrum has proved to be a highly informative indicator to summarize the functional structure of a community in both community research and monitoring programs in aquatic ecosystems. To demonstrate the relationships between the taxon-free resolution of protozoan communities and water conditions, the body-size spectra of biofilm-dwelling protozoa and their seasonal shift and environmental drivers were explored based on an annual dataset collected monthly from coastal waters of the Yellow Sea, northern China. Body sizes were calculated in equivalent spherical diameter (ESD). Among a total of 8 body-size ranks, S2 (19–27 μm), S3 (28–36 μm), S4 (37–50 μm) and S5 (53–71 μm) were the top four levels in frequency of occurrence, while rank S1 (13–17 μm), S2 and S4 were the dominant levels in abundance. These dominants showed a clear seasonal succession: S2/S4 (spring) → S2/S4 (summer) → S4 (autumn) → S2 (winter) in frequency of occurrence; S1 (spring) → S4 (summer) → S2 (autumn) → S1 (winter) in abundance. Bootstrapped average analysis showed a clear seasonal shift in body-size spectra of the protozoa during a 1-year cycle, and the best-matching analysis demonstrated that the temporal variations in frequency of occurrence and abundance were significantly correlated with water temperature, pH, dissolved oxygen (DO), alone or in combination with chemical oxygen demand (COD) and nutrients. Thus, the body-size spectra of biofilm-dwelling protozoa were seasonally shaped and might be used as a time and cost efficient bioindicator of water quality in marine ecosystems.     

添加剂对大孔吸附树脂固定化脂肪酶的影响

利用大孔吸附树脂DA-201为载体对海洋脂肪酶固定化,并探寻添加剂对固定化过程的影响。分别以NH_4Cl、甘露糖和甘氨酸为添加剂,采用单因素和正交实验相结合的方法优化条件。结果显示,以NH_4Cl为添加剂的最优条件:柠檬酸-柠檬酸钠缓冲液pH 6. 0,固定化温度30℃,载体投放量0. 5g,NH_4Cl浓度25mmol/L,固定化时间3. 0h,酶活力达到115. 27U/g;比不含有添加剂的固定化酶固定化效率提高47. 42%。以甘露糖为添加剂最优条件:磷酸二氢钾-氢氧化钠缓冲液pH7. 0,固定化温度35℃,载体投放量0. 5g,甘露糖浓度10mmol/L,固定化时间4. 5h;酶活力达到122. 75U/g,比不含有添加剂的固定化酶固定化效率提高6. 50%。以甘氨酸为添加剂的最优条件:磷酸二氢钾-氢氧化钠缓冲液pH7. 0,固定化温度20℃,载体投放量0. 5g,甘氨酸浓度为25mmol/L,固定化时间7. 5h;酶活力达到141. 69U/g,比不含有添加剂的固定化酶固定化效率提高26. 12%。采用不同添加剂对大孔吸附树脂DA-201的吸附固定化过程有较大影响,可以极大地提高吸附效率;同时发现缓冲液类型、pH、温度、添加剂浓度和固定化时间等对DA-201树脂吸附脂肪酶有很大影响,对后续吸附固定化工业酶研究有较好的参考价值。     

Structure-activity relationships study of neolamellarin A and its analogues as hypoxia inducible factor-1 (HIF-1) inhibitors

The novel marine pyrrole alkaloid neolamellarin A derived from sponge has been shown to inhibit hypoxia-induced HIF-1 activity. In this work, we designed and synthesized neolamellarin A and its series of derivatives by a convergent synthetic strategy. The HIF-1 inhibitory activity and cytotoxicity of these compounds were evaluated in Hela cells by dual-luciferase reporter gene assay and MTT assay, respectively. The results showed that neolamellarin A 1 (IC₅₀ = 10.8 ± 1.0 μM) and derivative 2b (IC₅₀ = 11.9 ± 3.6 μM) had the best HIF-1 inhibitory activity and low cytotoxicity. Our SAR research focused on the effects of key regions aliphatic carbon chain length, aromatic ring substituents and C-7 substituent on biological activity, providing a basis for the subsequent research on the development of novel pyrrole alkaloids as HIF-1 inhibitors and design of small molecule probes for target protein identification.     

Diversity and distribution of hidden cultivable fungi associated with marine animals of Antarctica

In the present study, we surveyed the distribution and diversity of fungal assemblages associated with 10 species of marine animals from Antarctica. The collections yielded 83 taxa from 27 distinct genera, which were identified using molecular biology methods. The most abundant taxa were Cladosporium sp. 1, Debaryomyces hansenii, Glaciozyma martinii, Metschnikowia australis, Pseudogymnoascus destructans, Thelebolus cf. globosus, Pseudogymnoascus pannorum, Tolypocladium tundrense, Metschnikowia australis, and different Penicillium species. The diversity, richness, and dominance of fungal assemblages ranged among the host; however, in general, the fungal community, which was composed of endemic and cold-adapted cosmopolitan taxa distributed across the different sites of Antarctic Peninsula, displayed high diversity, richness, and dominance indices. Our results contribute to knowledge about fungal diversity in the marine environment across the Antarctic Peninsula and their phylogenetic relationships with species that occur in other cold, temperate, and tropical regions of the World. Additionally, despite their extreme habitats, marine Antarctic animals shelter cryptic and complex fungal assemblages represented by endemic and cosmopolitan cold-adapted taxa, which may represent interesting models to study different symbiotic associations between fungi and their animal hosts in the extreme conditions of Antarctica.     

Evaluation of halophilic microalgae isolated from Rabigh Red Sea coastal area for biodiesel production: Screening and biochemical studies

In the present study, different water samples from Red Sea coastal area at Rabigh city, Saudi Arabia were studied for their dominant algal species. Microalgal isolation was carried out based on dilution method and morphologically examined using F/2 as a growth medium. Dry weight and main biochemical composition (protein, carbohydrates, lipids) of all species were performed at the end of the growth, and biodiesel characteristics were estimated. Nannochloropsis sp., Dunaliella sp., Tetraselmis sp., Prorocentrum sp., Chlorella sp., Nitzschia sp., Coscinodiscus sp., and Navicula sp. were the most dominant species in the collected water samples and were used for further evaluation. Nannochloropsis sp. surpassed all other isolates in concern of biomass production with the maximum recorded dry weight of 0.89 g L^?1, followed by Dunaliella sp. (0.69 g L^?1). The highest crude protein content was observed in Nitzschia sp. (38.21%) and Dunaliella sp. (18.01%), while Nannochloropsis sp. showed 13.38%, with the lowest recorded lipid content in Coscinodiscus sp. (10.09%). Based on the growth, lipid content, and biodiesel characteristics, the present study suggested Dunaliella sp. and Nitzschia sp. as promising candidates for further large-scale biodiesel production.     

Coral reef conservation in Bali in light of international best practice,a literature review

Bali, Indonesia sits within the coral triangle and is internationally recognised for its high coral reef diversity. The health of Bali’s marine ecosystems has declined in recent decades, and this is thought to be due to threats from climate change, destructive fishing practices, pollution, outbreaks coral eating invertebrates, coral disease and unsustainable tourism. As a response, multiple conservation strategies have been introduced by the island’s communities, non-government organisations and governments, with the aim of preventing further decline, as well as restoring already degraded coral reefs. This literature review provides an in-depth analysis of the tools used to conserve Bali’s coral reefs, and compares them to those used in other countries. In light of international ‘best practice’ in coral reef conservation, this review makes suggestions on how Bali could better conserve its coral reef ecosystems. These include (1) increasing its designation of official Marine Protected Areas (MPAS) and strengthening management of existing ones, (2) creating an MPA network, (3) substantially reducing marine plastic pollution, (4) continuing artificial reef construction in degraded habitats, (5) continuing to develop Bali as an ecotourism destination, (6) increasing engagement in global science to inform marine conservation decision-making, and (7) developing more marine monitoring programmes.     

中国西藏发现类三角蚌类祖先闯入非海相领域的证据（英文）北大核心CSCD

新发现的双壳类化石命名为Baxoitrigonia baxoiensis gen. et sp. nov.,产地为藏东八宿林卡家东,化石产于景星动物群之下的拉贡塘组下段,同层位有菊石和其他海相双壳类,时代为晚侏罗世Tithonian期;化石的外部特征很接近于三角蛤类Iotrigonia属,但前闭肌痕特征又相似于类三角蚌类,被认为是三角蛤类闯入非海相领域后演变成类三角蚌类的产物。此发现提供了生物和地层两方面的直接证据,证明非海相类三角蚌类(Trigonioidoidea超科)起源于海相三角蛤类(Trigoniida目),而不是起源于珠蚌类(Unionida目)。海相三角蛤类闯入边缘隔绝的洛隆-八宿地区并演变为非海相类三角蚌类,是一次典型的边域成种事件。     

Trophic coupling of the microbial and the classical food web in Lake Baikal,Siberia

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Population trends for humpback whales (Megaptera novaeangliae) foraging in the Francisco Coloane Coastal‐Marine Protected Area,Magellan Strait,Chile

In 2003 a feeding aggregation of southeastern Pacific humpback whales (Megaptera novaeangliae) was reported in the Magellan Strait. While Chile established its first marine national park in the Strait to protect humpback whale habitat, fatal ship strikes remain a concern because of overlap with a busy shipping lane. To better understand population risk, we estimated abundance and survival for this population using Bayesian robust‐design mark‐recapture models fit to photographic data from 2004 to 2016. Overall, the model estimated a total of 204 whales (95% CI: 199–210) during the last 12 yr, and 93 (95% CI: 86–100) in the 2016/2017 austral summer. The population grew at 2.3% (CI: 2.1%–3.1%), an annual increase of two whales. Annual survival (including calves) was estimated at 0.892 (CI: 0.871–0.910). Our results corroborate a persistent feeding population, but one that is increasing relatively slowly. Owing to its vulnerability stemming from its small size, coupled with significant overlap with a busy shipping lane, we argue this subpopulation is at significant risk from ship strikes and may be one of the few populations where anthropogenic mortalities could regulate population dynamics. We therefore encourage continued monitoring via photographic mark‐resighting surveys, and analyses explicitly investigating potential population‐level ship strike effects.