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The signaling pathways that allow plants to mount defenses against chewing insects are known to be complex. To investigate the role of jasmonate in wound signaling in Arabidopsis and to test whether parallel or redundant pathways exist for insect defense, we have studied a mutant (fad3-2fad7-2fad8) that is deficient in the jasmonate precursor linolenic acid. Mutant plants contained negligible levels of jasmonate and showed extremely high mortality (approximately 80%) from attack by larvae of a common saprophagous fungal gnat, Bradysia impatiens (Diptera: Sciaridae), even though neighboring wild-type plants were largely unaffected. Application of exogenous methyl jasmonate substantially protected the mutant plants and reduced mortality to approximately 12%. These experiments precisely define the role of jasmonate as being essential for the induction of biologically effective defense in this plant-insect interaction. The transcripts of three wound-responsive genes were shown not to he induced by wounding of mutant plants but the same transcripts could be induced by application of methyl jasmonate. By contrast, measurements of transcript levels for a gene encoding glutathione S-transferase demonstrated that wound induction of this gene is independent of jasmonate synthesis. These results indicate that the mutant will be a good genetic model for testing the practical effectiveness of candidate defense genes.

The susceptibility to five new insecticide mixtures (chlorosan, feroban, cygron, engeo, and kingbo) was studied in the 2nd and 4th instar larvae of the cotton leafworm Spodoptera littoralis. The efficiency and residual effects of these compounds against S. littoralis under field conditions were also investigated. Obtained results revealed that feroban was the most effective compared with the other toxicants, while engeo was the least toxic insecticide in both instars after 2 and 5 days from treatment. Data also indicated that feroban had the longest half-life while engeo recorded the shortest one. Biochemical analysis showed that the tested compounds caused pronounced changes in acetyl cholinesterase and phenol oxidase.

The response of tobacco (Nicotiana tabacum) suspension-cultured cells (BY-2) to nutrient starvation was investigated. When the cells that were grown in Murashige-Skoog medium containing 3% (w/v) sucrose were transferred to the same medium without sucrose, 30 to 45% of the intracellular proteins were degraded in 2 d. An analysis with sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that proteins were degraded nonselectively. With the same treatment, protease activity in the cell, which was measured at pH 5.0 using fluorescein thiocarbamoyl-casein as a substrate, increased 3- to 7-fold after 1 d. When the cysteine protease inhibitor (2S,3S)-trans-epoxysuccinyl-L-leucylamido- 3-methyl-butane (10 micromolar) was present in the starvation medium, both the protein degradation and the increase in the protease activity were effectively inhibited. Light microscopy analysis showed that many small spherical bodies accumulated in the perinuclear region of the cytosol 8 h after the start of the inhibitor treatment. These bodies were shown to be membrane-bound vesicles of 1 to 6 micrometers in diameter that contained several particles. Quinacrine stained these vesicles and the central vacuole; thus, both organelles are acidic compartments. Cytochemical enzyme analysis using 1-naphthylphosphate and beta-glycerophosphate as substrate showed that these vesicles contained an acid phosphatase(s). We suggest that these vesicles contribute to cellular protein degradation stimulated under sucrose starvation conditions

The impact of phosphorus (P) availability on root proliferation, proton efflux, and acid phosphatase activities in roots and leaves was investigated in two lines of common bean (Phaseolus vulgaris): BAT 477 and CocoT. Phosphorus was supplied as KH₂PO₄ at 0 and 60 μmol per plant (0P and 60P, respectively). Under P shortage, the plant growth was more restricted in CocoT than in BAT 477, shoots being more affected than roots. The root area increased significantly at 0P in both lines. Up to 1 week following P shortage, the proton efflux increased in both lines despite a higher extent in BAT 477 as compared to CocoT. Root acid phosphatase activity was significantly higher under P limitation in the both lines, this trend being more pronounced in BAT 477 than in CocoT. This was also true for the leaf acid phosphatase. Regardless of the bean line, higher values were recorded for the old leaves as compared to the young ones for this parameter. Interestingly, a significant correlation between Pi content in old leaves and their acid phosphatase activity was found in P-lacking (0P) plants of the both bean lines, suggesting that acid phosphatase may contribute to increase the phosphorus use efficiency in bean through the P remobilization from the old leaves. As a whole, our results highlight the significance of the root H+ extrusion and the acid phosphatase activity rather than the root proliferation in the relative tolerance of BAT 477 to severe P deficiency.

Nodulation process in legume plants is essential for biological nitrogen fixation during which process a large amount of phosphorus (P) is required. Under P deficiency, nodule formation is greatly affected, and induction of purple acid phosphatases (PAPs) is an adaptive strategy for nodules to acquire more P. However, regulation roles of PAPs in nodules remain largely understood. In this study, by transcriptome sequencing technology, five genes were found to be differentially expressed, which led to the greatly increased acid phosphatase (APase) and phytase activities in soybean mature nodules under P starvation conditions; and among the five genes, had the highest transcript level, and RT-PCR indicated expression of was gradually increasing during nodule development. GUS activity driven by promoter was also significantly induced in low phosphorus conditions. Further functional analysis showed that under low phosphorus stress, overexpression of resulted in higher nodule number, fresh weight, and nitrogenase activity as well as the APase activity than those of control plant nodules, whereas the growth performance and APase activity of nodules on hairy roots were greatly lower when was suppressed, indicating that may promote P utilization in soybean nodules under low P stress, which thus played an important role in nodulation and biological nitrogen fixation. Moreover, P1BS elements were found in the promoter of , and yeast one-hybrid experiment further proved the binding of P1BS by transcription factor GmPHR1 in the promoter of . At last, overexpression and suppression of in nodules indeed caused highly increased and decreased expression of , respectively, indicating that is regulated by GmPHR1 in soybean nodules. Taken together, these data suggested that was a novel soybean PAP involved in the P utilization and metabolism in soybean root nodules and played an important role in the growth and development of root nodules and biological nitrogen fixation.

The toxicity of Malathion, Diazinon, Methoxyfenozide and Lufenuron to adult males and females of Bactrocera zonata was studied under laboratory conditions. The results showed that Diazinon was the most toxic among the tested compounds followed by Malathion, Lufenuron and Methoxyfenozide. LC50 values were 0.20 ppm, 0.09 ppm and 0.02 ppm for males, and 0.91 ppm, 0.14 ppm and 0,01 ppm for females. The level of glutamic oxaloacetic transaminase (GOT) of treated adult males and females in 24 h, 48 h, and 72 h post treatment increased compared to untreated adults. The highest activities of GOT in treated adult males in 24 h, 48 h, and 72 h were 92.11 microM, 101.99 microM and 112.21 microM pyruvate released x 10**3/min/g FW (fresh weight), respectively, for Methoxyfenozide LC10, and in treated adult females after 24 h, 48 h, and 72 h they were 84.24 microM, 94.33 microM, and 111.12 microM pyruvate released x 10**3/min/g FW, respectively, for Diazinon LC25. The activities of acetylcholine esterase of treated adults decreased compared to untreated adults. The highest activities of acid phosphatase in adult males after 24 h and 48 h were 249.43 microg and 270.52 microg AchI hydrolysed/min/g FW, respectively, for Methoxyfenozide LC25. The highest activities of alkaline phosphatase in adult males were 139.04 microg, 175.67 microg, and 199.29 microg phenol x 10**3/min/g FW for Malathion LC10. In adult females they were 123.31 microg, 162.10 microg and 199.59 microg phenol x 10**3/min/g FW, respectively, for Lufenuron LC25 in 24 h, 48 h, and 72 h post treatment.

Hypoxia-inducible factor 1-α (HIF-1α) plays a critical role in angiogenesis-osteogenesis coupling during bone development and bone regeneration. Previous studies have shown that 17β-estradiol activates the HIF-1α signaling pathway and that mice with conditional activation of the HIF-1α signaling pathway in osteoblasts are protected from ovariectomy (OVX)-induced bone loss. In addition, it has been shown that hypoxia facilitates the osteogenic differentiation of mesenchymal stem cells (MSCs) and modulates Wnt/β-catenin signaling. Therefore, we hypothesized that activation of the HIF-1α signaling pathway by hypoxia-mimicking agents would prevent bone loss due to estrogen deficiency. In this study, we confirmed the effect of dimethyloxalylglycine (DMOG), a hypoxia-mimicking agent, on the HIF-1α signaling pathway and investigated the effect of DMOG on MSC osteogenic differentiation and the Wnt/β-catenin signaling pathway. We then investigated the effect of DMOG treatment on OVX-induced bone loss. Female C57BL/6J mice were divided into sham, OVX, OVX+L-DMOG (5 mg/kg/day), and OVX+H-DMOG (20 mg/kg/day) groups. At sacrifice, static and dynamic bone histomorphometry were performed with micro computed tomography (micro-CT) and undecalcified sections, respectively. Bone strength was assessed with the three-point bending test, and femur vessels were reconstructed and analyzed by micro-CT. Serum vascular endothelial growth factor (VEGF), osteocalcin, and C-terminal telopeptides of collagen type(CTX) were measured by ELISA. Tartrate-resistant acid phosphatase staining was used to assess osteoclast formation. Alterations in the HIF-1α and Wnt/β-catenin signaling pathways in the bone were detected by western blot. Our results showed that DMOG activated the HIF-1α signaling pathway, which further activated the Wnt/β-catenin signaling pathway and enhanced MSC osteogenic differentiation. The micro-CT results showed that DMOG treatment improved trabecular bone density and restored the bone microarchitecture and blood vessels in OVX mice. Bone strength was also partly restored in DMOG-treated OVX mice. Dynamic bone histomorphometric analysis of the femur metaphysic revealed that DMOG increased the mineralizing surface, mineral apposition rate, and bone formation rate. The serum levels of VEGF and osteocalcin were higher in DMOG-treated OVX mice. However, there were no significant differences in serum CTX or in the number of tartrate-resistant acid phosphatase-stained cells between DMOG-treated OVX mice and OVX mice. Western blot results showed that DMOG administration partly rescued the decrease in HIF-1α and β-catenin expression following ovariectomy. Collectively, these results indicate that DMOG prevents bone loss due to ovariectomy in C57BL/6J mice by enhancing angiogenesis and osteogenesis, which are associated with activated HIF-1α and Wnt/β-catenin signaling pathways.

Nine crop species were grown in P-sufficient and P-deficient nutrient solutions. The activity of acid phosphatase secreted by the roots increased under P-deficient conditions in all the species examined. That of lupin increased most remarkably. The properties of the enzyme secreted by the roots of lupin was investigated. Many isozymes existed in the roots and the leaves, but only one of them was secreted into the rhizosphere in a large amount. The molecular weight of the purified enzyme secreted was estimated to be 72 KD by SDS-PAGE and 140 KD by gel filtration; it was assumed to be a homo-dimer. The iso-electric point of the enzyme was 4.7 and the pH for optimum activity 4.3. When the enzyme was mixed with aqueous solution extracted from a P-deficient soil, its activity declined to 55% of its original activity after 14 days and to 9% after 21 days.

Isozymic and protein diversity among five sugarcane varieties viz., Co 6304, Co 85019, Co 8371, Co 89003 and Co 91010 were studied to understand the varietal interrelationship and to identify the biochemical marker for the disease resistance and stress tolerance. The standard technique of vertical gel electrophoresis PAGE was employed for size separation of isozymes. The gel was stained with different staining solutions for different isozyme systems viz. peroxidase, esterase, acid phosphatase, alkaline phosphatase and proteins. Rf values of the banding profiles, similarity index and variation between the varieties were analysed. Among the four enzyme systems, peroxidase profile reveals the difference between the disease resistant / susceptible and abiotic stress tolerant / non tolerant varieties. The two isoperoxidase bands with Rf values 0.62 and 0.66 showed their presence in disease resistant and abiotic tolerant varieties. The presence of two marker bands (0.62, 0.66) of resistant and stress tolerant varieties suggest that the variety Co 6304 may also be resistant to smut, wilt and moderately resistant to red rot and tolerant to drought.

Rice takes up phosphorous (P) as major nutrient source for its growth and development when grown under anaerobic water-logged soil conditions. To better understand the underlying mechanisms and to develop potential protein biomarkers of P-starvation, hydroponically-grown rice seedlings in the complete media and phosphorus absence (P-starvation) of phosphorous nutrient solutions were investigated for physiological and proteome changes. The P-starvation manifested significant reduction in root growth in three-week-old seedlings compared to respective complete media. Furthermore, P-starvation also showed increased activity of acid phosphatase in roots of one- and three-week-old seedlings, suggesting that experimental design is suitable for proteomics survey of P-starvation responsive proteins. Two-dimensional gel electrophoresis coupled with matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry analysis of total root protein from three-week-old seedlings identified 10 P-starvation responsive protein spots out of 140 high-quality protein spots. Identified 10 proteins were involved in metabolism and defense/stress response. Out of 10, 2 and 8 protein spots were found to be upand down-regulated, respectively. Semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) analysis of corresponding genes of four randomly selected proteins, including putative glyceraldehydes-3-phophate dehydrogenase (G3PDH, spot R1), S-adenosyl-l-methionine synthetase (SAMS, spot R4), ATP synthase subunit alpha (spot R6), and root-specific pathogenesisrelated protein 10 (PR-10, spot R8), showed that just as protein abundance, these proteins are also regulated at the transcript level. Results suggest identified P-starvation responsive proteins are involved in maintaining nutrient homeostasis and/or associated with changes in root physiology under the absence of P.