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In this study, the toxicity, behavioral and antioxidant activity effects of dimethylsulfoxide (DMSO) on planarian Dugesia japonica were investigated. The results showed that the mortality was directly proportional to the DMSO concentration, and planarian locomotor velocity decreased as the concentration of DMSO increased. The recovery of the motility for planarians pre-exposed to DMSO was found to be time- and dose-dependent, and only those pre-exposed to 0.1-3% DMSO resulted in full recovery. The antioxidant enzymes of planarians in response to long-term DMSO stress was also altered in a time- and dose-dependent manner. Planarians revealed more tolerance to DMSO toxicity at low DMSO (0.1%) level in short- and long-term DMSO stress, in which an efficient antioxidant system was involved and the motility was not affected.

Polysaccharides from Dendrobium officinale possess unparalleled medicinal value. In order to produce the active polysaccharides from D. officinale through tissue culture, the effects of salicylic acid on the accumulation of polysaccharides were investigated. Salicylic acid (SA) was beneficial to increasing the contents of polysaccharides. The highest polysaccharide production occurred on the medium supplied with 100 μmol·L −1 salicylic acid. After 30 days of culture the production of polysaccharides reached 10.09% and 15.81% by phenol-sulfuric acid method and 3, 5-dinitrosalicylic (DNS) colorimetric method respectively. The major constituent of polysaccharides, glucose and mannose, was determined by pre-column derivatization-HPLC. The results showed that the glucose contents were reduced and mannose contents were increased with different salicylic acid concentration. The ANOVA of the mannose contents demonstrated that among the different SAs concentration was significantly different. The SA application influenced polysaccharide production rather than degradation because the sucrose metabolic enzyme activities were modified by SA. The experiments suggest that salicylic acid could be an effective compound to enhance the production of active polysaccharides from D. officinale.

The nervous system is one of the most complex and fascinating organ systems in the metazoan. Neural networks regulate many aspects of animal physiology and behavior. The longheld doctrine that neurons are only produced in the embryo 1,2 has been challenged by the discovery that neurogenesis persists in the central nervous system (CNS) of adult animals. 3 It is now accepted that adult neurogenesis is a widespread phenomenon in different metazoans. 4,5 As vertebrates, zebrafish have shown that adult neurogenesis is along the entire rostral-caudal axis of the brain 6 and when their CNS

In this study, the toxicity, behavioural and regeneration effects of dimethylformamide (DMF) on planarian Dugesia japonica were investigated. One control and six different concentrations of DMF (10 ppm, 100 ppm, 500 ppm, 1000 ppm, 5000 ppm and 10,000 ppm) were used in triplicate. The results showed that the mortality was directly proportional to the DMF concentration and planarian locomotor velocity (pLMV) was significantly reduced by increasing the exposure time and DMF concentration. pLMV of D. japonica was significantly reduced at a lower concentration of 10 ppm after 7 days of continuous exposure to DMF. The recovery of the motility of planarians pretreated with DMF was found to be time- and dose dependent, all planarians had complete recovery in their motility after 48 h. The appearance of auricles in regenerating animals was easily affected by DMF exposure in comparison with the appearance of eyespot. The present results suggest that the intact adult mobility in the aquatic planarian D. japonica is a more sensitive biomarker than mortality, and the appearance of auricles in regenerating animals is a more sensitive biomarker than eyespot.

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A subtracted cDNA library of rice (Oryza sativa L.) inflorescence meristem (IM) was constructed using the suppression subtractive hybridization (SSH) method. The cDNAs of the rice shoot apical meristem (SAM) were used as "driver" and inflorescence meristem ( I . ) as "tester" in the experiment, respectively. Forty of 250 randomly chosen cDNA clones were identified by differential screening, which were IM-specific or IM-highly expressed. Most of the rice IM cDNAs cloned by SSH appear to represent rare transcripts, 40% of which were derived from truly differentially expressed genes. Of all the forty sequenced cDNA inserts, eleven contain the regions with 60%--90% identity to their homolog in GenBank, eighteen are expected to be new genes, only two correspond to published rice genes.Keywords: rice (Oryza sativa L.) cDNA, suppression subtractive hybridization, shoot apical meristem, inflorescence meristem.The suppression subtractive hybridization (SSH) is a new method developed for identifying differentially expressed genes between two different mRNA populations. Based on suppression PCR and suppression subtractive hybridization, SSH is designed to normalize and to amplify selectively cDNAs from different mRNA species with different abundances. Because selective amplification of target cDNA fragment (suppressing amplification of nontarget cDNA simultaneously) avoids laborious repeated hybridization and physical separation of ss and ds cDNA, SSH makes cloning of differentially expressed genes (including high, middle, low, rare abundance transcripts) as much as possible. The efficiency and reproducibility of SSH contributes its successful application in different studies for the identification of tissue-specific, developmental or induced, differentially expressed genes['41.In this note we report the results of identifying genes differentially expressed in rice inflorescence meristem other than that in shoot apical meristem with SSH technique. The transition from vegetative growth to reproductive development is a critical stage for the production of crops. cDNAs synthesized from inflorescence meristem poly(A+) RNA were subtracted against cDNAs from shoot apical meristem. The subtracted cDNAs were then cloned into pGEM-T vector to construct a subtracted library with 500 clones. 40 clones showing IM-specific or IM-increasing expression pattern have been identified by differentially screening with forward and reverse subtracted cDNA probes. Materials and methods( i ) Rice meristem materials. Rice (Oryza sativa L.) was planted in field. At the stages of vegetative growth and reproductive development initiation, shoot apical meristems and inflorescence meristems were collected after being detected under microscope, respectively.( ii ) mRNA isolation. Total RNA was isolated from plant material by a published method (Sacco de Vries 1998). Poly(A+) mRNA was purified from total RNA by two cycles of oligo(dT)-cellu-lose chromatography ( mRNA purification kit, Pharmacia ).(iii) Suppression subtractive hybridization. cDNA synthesis...

The accumulation of polysaccharides, activities of sucrose metabolism enzymes, and the expression of sucrose biosynthetic genes in Dendrobium officinale were significantly affected by exogenous methyl jasmonate (MeJA). Application of MeJA increased the content of polysaccharides and the highest polysaccharide production occurred in the samples treated with 200 μM MeJa. The MeJA application influenced polysaccharide biosynthesis rather than degradation because the activities of sucrose metabolism enzymes and the expressions of sucrose biosynthetic genes were upregulated by MeJA. Interestingly, low MeJA concentrations promoted accumulation of Dendrobium polysaccharides, while high MeJA amounts played an inhibitory role. The content of major constituent of polysaccharides, glucose and mannose, also increased after MeJa treatment.