Effects of fishery protection on biometry and genetic structure of two target sea cucumber species from the Mediterranean Sea

Sea cucumber fisheries are now occurring in most of the tropical areas of the world, having expanded from its origin in the central Indo-Pacific. Due to the overexploitation of these resources and the increasing demand from Asian countries, new target species from Mediterranean Sea and northeastern Atlantic Ocean are being caught. The fishery effects on biometry and genetic structure of two target species (Holothuria polii and H. tubulosa) from Turkey, were assessed. The heaviest and largest individuals of H. polii were found into the non-fishery area of Kusadasi, also showing the highest genetic diversity. Similar pattern was detected in H. tubulosa, but only the weight was significantly higher in the protected area. However, the observed differences on the fishery effects between species, could be explained considering the different percentage of catches (80% for H. polii and 20% for H. tubulosa)

Seasonal variations of digestive enzymes in sea cucumbers (Holothuria tubulosa, G. 1788) under culture conditions

Emiroglu, Dilek/0000-0001-8371-6407WOS: 000504439600001PubMed: 31880099Sea cucumber, Holothuria tubulosa (Gmelin, 1788), is an economically valuable species due to its rich nutrients content that being exported in Turkey. However, culture of this species is difficult due to a lack of knowledge. the main objective of this study is to investigate seasonal activities of main digestive enzymes (protease, lipase, and amylase) for nutritional requirements. in this sense, sea cucumbers were stocked in the glass aquarium and sediment was 10 cm. It was replaced monthly and enriched (1% of the living individual weight) by dried Sargassum sp. Total protease and amylase enzymes have shown higher activity compared to lipase. All three enzyme activities were maximum in the summer and minimum in the winter. in summer, the highest measured total protease, amylase, and lipase activity values were 6.45 +/- 0.66, 6.77 +/- 0.72, and 2.78 +/- 0.32 U/mg per protein, respectively. in winter, the lowest total protease, amylase, and lipase activity values were measured as 2.03 +/- 0.16, 1.14 +/- 0.14, and 0.12 +/- 0.01 U/mg per protein, respectively. As a conclusion of the study, seasonal expression of the main digestive enzymes was strictly dependent on water temperatures and food abundance and also it was ideal to feed this species with food containing high protein and carbohydrate under appropriate temperatures for commercial culture

Phosphorus acquisition by citrate- and phytase-exuding Nicotiana tabacum plant mixtures depends on soil phosphorus availability and root intermingling

Citrate and phytase root exudates contribute to improved phosphorus (P) acquisition efficiency in Nicotiana tabacum (tobacco) when both exudates are produced in a P deficient soil. To test the importance of root intermingling in the interaction of citrate and phytase exudates, Nicotiana tabacum plant-lines with constitutive expression of heterologous citrate (Cit) or fungal phytase (Phy) exudation traits were grown under two root treatments (roots separated or intermingled) and in two soils with contrasting soil P availability. Complementarity of plant mixtures varying in citrate efflux rate and mobility of the expressed phytase in soil was determined based on plant biomass and P accumulation. Soil P composition was evaluated using solution (31) P NMR spectroscopy. In the soil with limited available P, positive complementarity occurred in Cit+Phy mixtures with roots intermingled. Root separation eliminated positive interactions in mixtures expressing the less mobile phytase (Aspergillus niger PhyA) whereas positive complementarity persisted in mixtures that expressed the more mobile phytase (Peniophora lycii PhyA). Soils from Cit+Phy mixtures contained less inorganic P and more organic P compared to monocultures. Exudate-specific strategies for the acquisition of soil P were most effective in P-limited soil and depended on citrate efflux rate and the relative mobility of the expressed phytase in soil. Plant growth and soil P utilization in plant systems with complementary exudation strategies are expected to be greatest where exudates persist in soil and are expressed synchronously in space and time