Enhanced resistance of Portunus trituberculatus to Vibrio alginolyticus by selective breeding

We established a line (screened) of Portunus trituberculatus by selectively breeding individuals that survived from challenge with Vibrio alginolyticus, and compared the response of screened and unscreened (control) P. trituberculatus challenged with V. alginolyticus. We measured superoxide dismutase, catalase, acid phosphatase, alkaline phosphatase, and peroxidase activity and the content of hemocyanin in the plasma and phenoloxidase activity in serum. The cumulative survival rate after 24-h challenge with V. alginolyticus was significantly higher in the screened crabs than in the unscreened crabs (P<0.05). T-SOD and PO activity were significantly lower in the screened stock than in the unscreened stock (P<0.05). POD, CAT, and ACP activity and hemocyanin content were significantly higher in the screened stock than in the unscreened stock. Our results suggest that the screened stock was more resistant to infection. Furthermore, the indices we measured may be used to evaluate the health state of P. trituberculatus.     

Screening and characterization of the alkaline protease isolated from PLI-1, a strain of Brevibacillus sp. collected from Indonesia’s hot springs

A total of 69 strains of thermophilic bacteria were isolated from water, soil and sediment samples from three Indonesia’s hot spring areas (Pantai cermin, Kalianda and Banyu wedang) by using Minimal Synthetic Medium (MSM). The extreme thermophile Brevibacillus sp. PLI-1 was found to produce extracellular thermophilic alkaline protease with optimal activity at 70℃ and pH 8.0-9.0. The molecular weight of the protease was estimated to be around 56 kD by SDS-PAGE. The maximum activity of the protease was 26.54 U mL-1. The protease activity did not decrease after 30 min and still retained more than 70% of relative activity after 60 min at 70℃ and pH 8.0. The ion Mg2+ was found to promote protease activity at both low and high concentrations, whereas Cu2+ and Zn2+ could almost completely inhibit the activity. Divalent cation chelator EDTA inhibited the enzyme activity by 55.06% ± 0.27%, while the inhibition caused by PMSF, Leupeptin, Pepstain A and Benzamidine were 66.78% ± 3.25%, 52.37% ± 0.25%, 62.47% ± 2.96% and 50.99% ± 0.24%, respectively. Based on these observations, the enzyme activity was conspicuously sensitive to the serine and cysteine protease inhibitors. All these results indicated that the protease isolated from the strain PLI-1 was a thermophilic protease and had a high-temperature stability and a pH stability.     

Abundance and Distribution of Fatty Acids in Sediments of the South Mid-Atlantic Ridge

Sediment samples obtained from the South Mid-Atlantic Ridge were studies by gas chromatography-mass spectrometer(GC-MS) for the abundance and distributions of total fatty acids(TFAs). Approximately 34 fatty acids were identified, with the chain-lengths ranging from C12 to C30. The total concentrations of TFAs(∑TFA) ranged from 7.15 to 30.09 μg g-1 dry sediment, and ∑TFA was weakly correlated with bitumen content(R2 = 0.69). The ∑TFA of samples around hydrothermal areas were significantly higher than that of samples away from hydrothermal areas, indicating intense primary production and large biomass in the hydrothermal areas, and suggesting a close relationship between hydrothermal activity and ∑TFA of samples. The characteristics of the TFA composition in the present study are rich in monounsaturated fatty acids and lacking in polyunsaturated fatty acids, and the ratios between the concentrations of monounsaturated fatty acids and ΣTFAs in samples close to the hydrothermal areas, are about 0.8, but for samples far from the hydrothermal areas, they are only about 0.5. Several fatty acids(e.g., a/i C15:0 and C16:1ω7), which are signature biomarkers for sulfur-metabolizing bacteria, show the same distribution trend as ∑TFA of samples, further highlighting the close relationship between fatty acid content and hydrothermal activity and/or hydrothermal communities. The metabolic activities of hydrothermal communities, especially those of microorganisms, are likely the main source of fatty acids in samples.     

可控源音频大地电磁测深法在西峪矿区金刚石原生矿找矿中的应用

可控源音频大地电磁测深法是深部找矿的有效地球物理手段之一,该文以山东省蒙阴县西峪矿区为例,探讨了可控源音频大地电磁测深法在金刚石原生矿找矿中的应用,并对测线反演电阻率断面图上的低阻异常进行解译,金伯利岩在断面图上多为低阻与高阻之间的梯度带,其解译结果与钻探验证结果相吻合,进一步证明该方法在金刚石原生矿找矿是行之有效的手段。     

Soil Organic Carbon Contents and Stocks in Coastal Salt Marshes with Spartina alterniflora Following an Invasion Chronosequence in the Yellow River Delta,China

Plant invasion alters the fundamental structure and function of native ecosystems by affecting the biogeochemical pools and fluxes of materials and energy. Native(Suaeda salsa) and invasive(Spartina alterniflora) salt marshes were selected to study the effects of Spartina alterniflora invasion on soil organic carbon(SOC) contents and stocks in the Yellow River Delta. Results showed that the SOC contents(g/kg) and stocks(kg/m~2) were significantly increased(P 0.05) after Spartina alterniflora invasion of seven years, especially for the surface soil layer(0–20 cm). The SOC contents exhibited an even distribution along the soil profiles in native salt marshes, while the SOC contents were gradually decreased with depth after Spartina alterniflora invasion of seven years. The natural ln response ratios(Ln RR) were applied to identify the effects of short-term Spartina alterniflora invasion on the SOC stocks. We also found that Spartina alterniflora invasion might cause soil organic carbon losses in a short-term phase(2–4 years in this study) due to the negative Ln RR values, especially for 20–60 cm depth. And the SOCD in surface layer(0–20 cm) do not increase linearly with the invasive age. Spearman correlation analysis revealed that silt + clay content was exponentially related with SOC in surface layer(Adjusted R~2 = 0.43, P 0.001), suggesting that soil texture could play a key role in SOC sequestration of coastal salt marshes.     

Changes of Biogenic Elements in Phragmites australis and Suaeda salsa from Salt Marshes in Yellow River Delta,China

Little information is available on biogenic elements(carbon, nitrogen, phosphorus and sulfur) and the ecological stoichiometric characteristics of plants in coastal wetlands. To investigate the contents of carbon, nitrogen, phosphorus and sulfur of plants, and their ecological stoichiometric characteristics in the Yellow(Huanghe) River Delta, plant samples were collected from two typical salt marshes(Suaeda salsa and Phragmites australis wetlands) during the period of from August to October in 2007, and the ratios of C/N, C/P, N/P, C/N/P and C/N/P/S were calculated. Results showed that during the studying period, plant C, N and P were lower than the global average values, and plant N and P were lower than the China's average values. Leaf C and S in Suaeda salsa were significantly lower than those in Phragmites australis(P 0.05), and leaf N and P in Suaeda salsa and Phragmites australis showed no significant differences(P 0.05). Average C/N ratios were 23.75 in leaf, 73.36 in stem, 65.67 in root of Suaeda salsa, and 33.77 in leaf, 121.68 in stem, 97.13 in root of Phragmites australis. Average C/N ratios of Suaeda salsa and Phragmites australis were all great than 25, indicating the salt marsh in the Yellow River Delta is an N limitation system. Average C/P ratios were 276.78 in leaf, 709.28 in stem and 1031.32 in root of Suaeda salsa, and 536.94 in leaf, 768.13 in stem and 875.22 in root of Phragmites australis. The average N/P ratios of Suaeda salsa were 12.92 in leaf, 10.77 in stem and 10.91 in root, and the average N/P ratios of Phragmites australis were 16.40 in leaf, 7.40 in stem and 6.92 in root, indicating the Suaeda salsa wetlands were N limited and Phragmites australis wetlands were N limited in August and P limited in October in 2007. The average C/N, C/P and C/N/P ratios in Suaeda salsa and Pragmites australis were higher than the global average values, indicating the lower quality of organic matter provided by wetland plants in the Yellow River delta.     

禁食暂养对卵形鲳鲹有水保活生理响应的影响

【目的】探究禁食暂养对卵形鲳鲹有水保活生理响应的影响,为卵形鲳鲹的保活运输奠定基础。【方法】通过测定暂养过程中水体的总氨氮和pH值、卵形鲳鲹血液生理生化指标、肌肉氧化应激指标等的变化,分析确定卵形鲳鲹有水保活的禁食暂养条件。【结果与结论】禁食暂养过程中,随着暂养时间的延长,水体总氨氮含量与pH值显著上升,但在禁食暂养时间为6 h时,其总氨氮质量浓度为3.22 mg/L和pH值为7.80;禁食暂养6 h可以降低或减少卵形鲳鲹的应激,使血液中乳酸脱氢酶(LDH)和谷草转氨酶(AST)活性以及皮质醇(Cortisol)、血糖(GLU)、尿素氮(BUN)和总胆固醇(T-CHO)含量处于较低水平,分别为2785.53 U/L、19.04 U/L、158.72 ng/mL、2.98 mmol/L、4.35 mmol/L和4.96 mmol/L;同时减轻了应激带来的肌肉组织氧化损失,使过氧化氢酶(CAT)活性和丙二醛(MDA)含量维持在较低水平,分别为6.34 U/L和5.86 mmol/L;卵形鲳鲹适宜的暂养条件为在鱼水比m鱼∶m水=1∶20和(25±1)℃的洁净海水中暂养6 h。     

Identification of paralytic shellfish toxin-producing microalgae using machine learning and deep learning methods

Journal of Oceanology and Limnology - Paralytic shellfish poisoning (PSP) microalgae, as one of the harmful algal blooms, causes great damage to the offshore fishery, marine culture, and marine...