Graphical abstract

Marine invertebrates including sponges, soft coral, tunicates, mollusks and bryozoan have proved to be a prolific source of bioactive natural products. Among marine-derived metabolites, terpenoids have provided a vast array of molecular architectures. These isoprenoid-derived metabolites also exhibit highly specialized biological activities ranging from nerve regeneration to blood-sugar regulation. As a result, intense research activity has been devoted to characterizing invertebrate terpenes from both a chemical and biological standpoint. This review focuses on the chemistry and biology of terpene metabolites isolated from the Red Sea ecosystem, a unique marine biome with one of the highest levels of biodiversity and specifically rich in invertebrate species.

Cultivated lands in erosion prone agro-ecologies incessantly experience a substantial loss of productive soil and organic matter. Currently, the fertility-management and rainwater-conservation practices are given emphasis separately. This study appraised collectively both the water-conservation and fertility-management practices for the restoration of soil productivity in eroded farmlands. Field experiments were carried out on wheat (Triticum aestivum L.) and maize (Zea mays L.) in eight farmer fields. Four fields of Missa soil series (Typic Ustochrept) and four of Rajar soil series (Typic Ustorthent) were selected. Treatments in each field were: farmers' practice as control without soil-water conservation, and with farmers' rate of fertilizer (per hectare 40 kg N'30 kg P 2 O 5 ); improved fertilization (per hectare 100 kg N, 60 kg P 2 O 5, 2 kg Zn, and 1 kg B) without soil-water-conservation practices; soil-water-conservation practices (deep plowing, bund improvement, ploughing across the contour)'farmers' rate of fertilizers; and soil-water conservation'improved fertilization. Crop grain yields were at the highest with soil-water conservation'improved fertilization (per hectare wheat 3.31 Mg and 1.65 Mg in 2004Á2005 and 2005Á2006; and maize 4.55 Mg and 4.19 Mg in 2005 and 2006, respectively). The lowest yields were recorded under farmers' practice for both crops. Similar was the response for water-use efficiency and plant uptake of nitrogen, phosphorus, zinc, and boron. Missa soil series was more responsive than was Rajar to integrated soil-management practices. Synergistic application of soil-water conservation and improved fertilization practices significantly improved the crop yields, nutrient uptake, and water-use efficiency.

S oil erosion is a complex process that depends on soil properties and erosion-induced loss in soil productivity is one of the major threats to global food and economic security. Erosion in excess of soil production would ultimately result in reduced agricultural potential. Crop yields in the Pothwar plateau (latitude 32º 10′ to 34º 9′ N and longitude 71º 10′ to 71º 55′ E) are low as compared to irrigated regions of Pakistan. Pothwar plateau is a large rain-fed tract of Pakistan which comprises of 1.8 m ha area (Nizami et al., 2004). Maize, sorghum and millet are the main crops during the summer season; and wheat is the predominant crop during the winter. Main causes of low production are; highly erratic, unevenly distributed rainfall, erosion, water runoff, and widespread deficiency of plant nutrients. Nutrient loss through Abstract | Erosion is one of the complex and detrimental types of land degradation that deteriorates both soil quality and land productivity. Determination of soil characteristics and nutrient status of eroded lands is pre-requisite for restoring their productivity. The objective of present study was to quantify the selected soil properties and nutrient status of eroded soils. The study was undertaken on eight soil series (Missa, Pirsabak, Guliana, Rajar, Balkassar, Rawalpindi, Chakwal and Satwal) in tehsil Gujar Khan of Rawalpindi district. Amongst the soil characteristics of selected fields, pH ranged from 7.36-7.94 for surface soil (0-15 cm) and 7.49-7.94 for subsoil (30-45 cm), EC1:1 was 0.22-0.38 dSm -1 in surface soil and 0.21-0.28 dSm -1 in subsoil, CaCO 3 was 1.0-9.22% in top soil and 0.28-9.67% in the subsoil and soil organic matter (OM) was 0.89-1.25% in surface soil and 0.62-1.04% in subsoil. Among soil series, Missa soil series had higher OM (1.25% and 1.04% in surface and sub-surface soil, respectively) compared with other soil series. All soils were generally deficient in nutrients as NO 3 -N was deficient in 97% surface soils (2.77-5.23 mg kg -1 ) and 100% sub soils (1.03-4.14 mg kg -1 ), P was deficient in 95% surface soils (0.76-1.67 mg kg -1 ) and 100% sub soils (0.22-1.22 mg kg -1 ), Zn was deficient in 100% both surface and subsoils and B was deficient in 85% surface soils and 90% subsoils. These results suggested that fertility status of these soils with respect to NO3-N, P, Zn and B was poor. The characterization of eroded lands provides a quantitative data and on the basis of this data application of integrated soil conservation practices could improve the soil sustainability and crop productivity of eroded lands. Furthermore, this data could also be helpful in developing policies, strategies and programs for the conservation of eroded lands.

The yield of three large scale cultures of Scenedesmus acutus, Chlorella vulgaris, and Coelastrum proboscideum was drum dried. The amino acid composition of the three species proved to compare well with the FAO (11) amino acid pattern except for methionine and isoleucine. Bio-assay evaluation of the three algal proteins gave the following values: protein efficiency ratio, 1.9-2.1; net protein ratio, 2,4-2.8; biological value, 75-78; digestibility coefficient 88-89; and calculated net protein utilization 67-69. Total nucleic acid content was about 4%. Uric acid content in the plasma of rats fed Scenedesmus, Chlorella, and Coelastrum diets was significantly higher (P less than 0.05) than in plasma of rats fed on a casein diet.