A Study on Evaluation of Alkaline and Acid Phosphatase Isozymes During Different Developmental Stages of New Breeding Lines and Races of Bombyx mori L

It is interesting to note that different silkworm races reared in laboratory offer an important testing ground for the application of biochemical methods to taxonomic problems. Moreover, there is scarcity of knowledge on enzyme studies in new breeding lines and races of silkworm specially Bombyx mori L. Therefore, we designed the present study with the main goal to evaluate the activities of alkaline and acid phosphatases quantitatively during different developmental stages of new breeding lines and races viz. Kalimpong-A (KA), B18, Pure Mysore (PM), evolved R1 and R2 of Bombyx mori L. Quantitative estimations of in alkaline and acid phosphatases were expressed in terms of enzyme activity. Alkaline and acid phosphatase activities during the different developmental stages of KA, NB18, PM, evolved R1 & R2 races were determined using Sodium-1 naphthahyl phosphate as a substrate following the dye-coupling method. The assay mixture included 2 ml of substrate and 0.2 ml of enzyme extract and incubation was made for 30 minutes at 25°c. The reaction was stopped by adding 2 ml of post coupling solution (5 parts of 4% sodium dodecyl sulphate and 2 parts of 0.2% Fast red TR salt) and colorimetric determination were made at 540 nm. Results illustrated that the activity of phosphatases was found to be different and high activity was found in the larval stage, which is feeding stage followed by pupae.

Increased Nodular P Level Induced by Intercropping Stimulated Nodulation in Soybean Under Phosphorus Deficiency

Low P availability is a vital constraint for nodulation and efficient N2 fixation of legume, including soybean. To elucidate the mechanisms involved in nodule adaption to low P availability under legume/cereal intercropping systems, two experiments consisting of three cropping patterns (monocropped soybean, monocropped maize, soybean/maize intercropping) were studied under both sufficient-and deficient-P levels. Our results demonstrated that intercropped soybean with maize showed a higher nodulation and N2 fixation efficiency under low P availability than monocropped soybean as evidenced by improvement in the number, dry weight and nitrogenase activity of nodules. These differences might be attributed to increase in P level in intercropping-induced nodules under low P supply, which was caused by the elevated activities of phytase and acid phosphatases in intercropping-induced nodules. Additionally, the enhanced expression of phytase gene in nodules supplied with deficient P level coincided with an increase in phytase and acid phosphatase activities. Our results revealed a mechanism for how intercropped maize stimulated nodulation and N2 fixation of soybean under P deficient environments, where enhanced synthesis of phytase and acid phosphatases in intercropping-induced nodules, and stimulated nodulation and N2 fixation.

Identification and Functional Analysis of Two Purple Acid Phosphatases AtPAP17 and AtPAP26 Involved in Salt Tolerance in Arabidopsis thaliana Plant

Tolerance to salinity is a complex genetic trait including numerous physiological processes, such as metabolic pathways and gene networks; thereby, identification of genes indirectly affecting, as well as those directly influencing, is of utmost importance. In this study, we identified and elucidated the functional characterization of AtPAP17 and AtPAP26 genes, as two novel purple acid phosphatases associated with high-salt tolerance in NaCl-stressed conditions. Here, the overexpression of both genes enhanced the expression level of AtSOS1, AtSOS2, AtSOS3, AtHKT1, AtVPV1, and AtNHX1 genes, involving in the K+/Na+ homeostasis pathway. The improved expression of the genes led to facilitating intracellular Na+ homeostasis and decreasing the ion-specific damages occurred in overexpressed genotypes (OEs). An increase in potassium content and K+/Na+ ratio was observed in OE17 and OE26 genotypes as well; however, lower content of sodium accumulated in these plants at 150 mM NaCl. The overexpression of these two genes resulted in the upregulation of the activity of the catalase, guaiacol peroxidase, and ascorbate peroxidase. Consequently, the overexpressed plants showed the lower levels of hydrogen peroxide where the lowest amount of lipid peroxidation occurred in these lines. Besides the oxidation resistance, the boost of the osmotic regulation through the increased proline and glycine-betaine coupled with a higher content of pigments and carbohydrates resulted in significantly enhancing biomass production and yield in the OEs under 150 mM NaCl. High-salt stress was also responsible for a sharp induction on the expression of both PAP17 and PAP26 genes. Our results support the hypothesis that these two phosphatases are involved in plant responses to salt stress by APase activity and/or non-APase activity thereof. The overexpression of PAP17 and PAP26 could result in increasing the intracellular APase activity in both OEs, which exhibited significant increases in the total phosphate and free Pi content compared to the wild-type plants. Opposite results witnessed in mutant genotypes (Mu17, Mu26, and DM), associating with the loss of AtPAP17 and AtPAP26 functions, clearly confirmed the role of these two genes in salt tolerance. Hence, these genes can be used as candidate genes in molecular breeding approaches to improve the salinity tolerance of crop plants.

Leaf Phosphorus Concentration Regulates the Development of Cluster Roots and Exudation of Carboxylates in Macadamia integrifolia

Phosphorus (P) deficiency induces cluster-root formation and carboxylate exudation in most Proteaceae. However, how external P supply regulates these root traits in Macadamia integrifolia remains unclear. Macadamia plants were grown hydroponically with seven P levels to characterize biomass allocation, cluster-root development, and exudation of carboxylates and acid phosphatases. Plant biomass increased with increasing P supply, peaking at 5 μM P, was the same at 5–25 μM P, and declined at 50–100 μM P. Leaf P concentration increased with increasing P supply, but shoot biomass was positively correlated with leaf P concentration up to 0.7–0.8 mg P g–1 dry weight (DW), and declined with further increasing leaf P concentration. The number of cluster roots declined with increasing P supply, with a critical value of leaf P concentration at 0.7–0.8 mg P g–1 DW. We found a similar trend for carboxylate release, with a critical value of leaf P concentration at 0.5 mg g–1 DW, but the activity of acid phosphatases showed a gradually-decreasing trend with increasing P supply. Our results suggest that leaf P concentration regulates the development and functioning of cluster roots, with a critical P concentration of 0.5–0.8 mg g–1, above which macadamia growth is inhibited.

Cow milk and its dairy products ameliorate bone toxicity in the Coragen-induced rat model

Coragen is an insecticide that stimulates calcium release from intracellular stores of muscle cells causing death to sensitive species. The present study aimed to evaluate the bone toxic effect of Coragen and the potential therapeutic effect of cow milk, yogurt, and soft cheese in rats. Toxicity was induced by Coragen administration with different doses of 1/20 or 1/40 LD50 in rats. Groups of rats (n = 6) were treated with either 5 g milk, 5 g yogurt, or 1.5 g cheese. Coragen administration elevated alkaline and acid phosphatases activity and reduced the calcium and phosphorus level in urine and serum of rats administered with Coragen. Femur and tibia length, thickness, weight, and breaking force were decreased by Coragen administration and femur Ca and P contents as well. Bone mineral area (BMA), bone mineral content (BMC), bone mineral density (BMD), protein profile (total, albumin, and globulin), and antioxidant system (TAC, GSH, GPX, GST, and SOD) were decreased by Coragen. All these parameters were improved on the treatment with milk and milk products. The results showed that yogurt treatment was significantly superior to the other treatments in increasing BMD (27%), breaking force (9%), femur Ca (41%), serum Ca (14%), and serum P (16%) and in reducing acid phosphatases (14%) and urine Ca and P by 8 and 10%, respectively. It can be concluded that the treatment with milk and milk products may provide treatment against osteoporosis and toxicity caused by Coragen.