Metaproteomics reveals the molecular mechanism underlying bloom maintenance of a marine dinoflagellate under low ambient CO2 and inorganic nutrients.

Dinoflagellate blooming periods are paradoxically characterized by high biomass growth rate and low ambient dissolved CO2 and inorganic nutrients, however, the underlying mechanisms linking cell growth and nutrient acquisition are poorly understood. Here, we compared metaproteomes of non-bloom, mid-blooming and late-blooming cells of a marine dinoflagellate Prorocentrum donghaiense. Cell division, metabolism of carbon, nitrogen, phosphorus, lipid, porphyrin and chlorophyll were more active in blooming cells than in non-bloom cells. Up-regulation of carbonic anhydrase, ribulose-1,5-bisphosphate carboxylase/oxygenase II, and C4-cycle proteins enhanced CO2 assimilation of P. donghaiense. Proteins participating in external organic nutrient acquisition and conversion, such as transporters for fatty acids, peptides and amino acids, external- and internal-phosphomonoester hydrolase, and diverse peptidases and amino acid transaminases, exhibited higher expression in blooming cells relative to non-bloom cells. Interestingly, dissolved organic nitrogen (DON) such as urea and aspartate significantly down-regulated expression and activity of carbon assimilation proteins except for RuBisCO form II, suggesting that DON provided sufficient carbon source which reduced the need to concentrate internal CO2. This study demonstrates that coupling of efficient CO2 assimilation with DON utilization are essential for bloom maintenance of P. donghaiense, and future efforts should be devoted to dissolved organic nutrients for prevention and management of dinoflagelllate blooms.

Transcriptomic response to changing ambient phosphorus in the marine dinoflagellate Prorocentrum donghaiense.

Dinoflagellates represent major contributors to the harmful algal blooms in the oceans. Phosphorus (P) is an essential macronutrient that limits the growth and proliferation of dinoflagellates. However, the specific molecular mechanisms involved in the P acclimation of dinoflagellates remain poorly understood. Here, the transcriptomes of a dinoflagellate Prorocentrum donghaiense grown under inorganic P-replete, P-deficient, and inorganic- and organic P-resupplied conditions were compared. Genes encoding low- and high-affinity P transporters were significantly down-regulated in the P-deficient cells, while organic P utilization genes were significantly up-regulated, indicating strong ability of P. donghaiense to utilize organic P. Up-regulation of membrane phospholipid catabolism and endocytosis provided intracellular and extracellular organic P for the P-deficient cells. Physiological responses of P. donghaiense to dissolved inorganic P (DIP) or dissolved organic P (DOP) resupply exhibited insignificant differences. However, the corresponding transcriptomic responses significantly differed. Although the expression of multiple genes was significantly altered after DIP resupplementation, few biological processes varied. In contrast, various metabolic processes associated with cell growth, such as translation, transport, nucleotide, carbohydrate and lipid metabolisms, were significantly altered in the DOP-resupplied cells. Our results indicated that P. donghaiense evolved diverse DOP utilization strategies to adapt to low P environments, and that DOPs might play critical roles in the P. donghaiense bloom formation.

Functional Differences in the Blooming Phytoplankton Heterosigma akashiwo and Prorocentrum donghaiense Revealed by Comparative Metaproteomics.

Phytoplankton blooms are natural phenomena in the ocean, which are the results of rapid cell growth of some phytoplankton species in a unique environment. However, little is known about the molecular events occurring during the bloom. Here, we compared metaproteomes of two phytoplankton Heterosigma akashiwo and Prorocentrum donghaiense in the coastal East China Sea. H. akashiwo and P. donghaiense accounted for 7.82% and 4.74% of the phytoplankton community protein abundances in the nonbloom sample, whereas they contributed to 60.13% and 78.09%, respectively, in their individual blooming samples. Compared with P. donghaiense, H. akashiwo possessed a significantly higher abundance of light-harvesting complex proteins, carbonic anhydrasem and RuBisCO. The blooming H. akashiwo cells expressed more proteins related to external nutrient acquisition, such as bicarbonate transporter SLC4, ammonium transporter, nitrite transporter, and alkaline phosphatase, while the blooming P. donghaiense cells highly expressed proteins related to extra- and intracellular organic nutrient utilization, such as amino acid transporter, 5'-nucleotidase, acid phosphatase, and tripeptidyl-peptidase. The strong capabilities of light harvesting, as well as acquisition and assimilation of inorganic carbon, nitrogen, and phosphorus, facilitated the formation of the H. akashiwo bloom under the high turbidity and inorganic nutrient-sufficient condition, whereas the competitive advantages in organic nutrient acquisition and reallocation guaranteed the occurrence of the P. donghaiense bloom under the inorganic nutrient-insufficient condition. This study highlights the power of metaproteomics for revealing the underlying molecular behaviors of different coexisting phytoplankton species and advances our knowledge on the formation of phytoplankton blooms.IMPORTANCE A deep understanding of the mechanisms driving bloom formation is a prerequisite for effective bloom management. Metaproteomics was applied in this study to reveal the adaptive and responsive strategies of two coexisting phytoplankton species, H. akashiwo and P. donghaiense, during their bloom periods. Metabolic features and niche divergence in light harvesting, as well as carbon, nitrogen, and phosphorus acquisition and assimilation likely promoted the bloom occurrence under different environments. The molecular behaviors of coexisting bloom-causing species will give clues for bloom monitoring and management in the oceans.

Unraveling the molecular mechanism of the response to changing ambient phosphorus in the dinoflagellate Alexandrium catenella with quantitative proteomics.

Phosphorus (P) is a key macronutrient limiting cell growth and bloom formation of marine dinoflagellates. Physiological responses to changing ambient P have been investigated in dinoflagellates; however, the molecular mechanisms behind these responses remain limited. Here, we compared the protein expression profiles of a marine dinoflagellate Alexandrium catenella grown in inorganic P-replete, P-deficient, and inorganic- and organic-P resupplied conditions using an iTRAQ-based quantitative proteomic approach. P deficiency inhibited cell growth and enhanced alkaline phosphatase activity (APA) but had no effect on photosynthetic efficiency. After P resupply, the P-deficient cells recovered growth rapidly and APA decreased. Proteins involved in sphingolipid metabolism, organic P utilization, starch and sucrose metabolism, and photosynthesis were up-regulated in the P-deficient cells, while proteins associated with protein synthesis, nutrient assimilation and energy metabolism were down-regulated. The responses of the P-deficient A. catenella to the resupply of organic and inorganic P presented significant differences: more biological processes were enhanced in the organic P-resupplied cells than those in the inorganic P-resupplied cells; A. catenella might directly utilize G-6-P for nucleic acid synthesis through the pentose phosphate pathway. Our results indicate that A. catenella has evolved diverse adaptive strategies to ambient P deficiency and specific mechanisms to utilize dissolved organic P, which might be an important reason resulting in A. catenella bloom in the low inorganic P environment. BIOLOGICAL SIGNIFICANCE: The ability of marine dinoflagellates to utilize different phosphorus (P) species and adapt to ambient P deficiency determines their success in the ocean. In this study, we investigated the response mechanisms of a dinoflagellate Alexandrium catenella to ambient P deficiency, and resupply of inorganic- and organic-P at the proteome level. Our results indicated that A. catenella initiated multiple adaptive strategies to ambient P deficiency, e.g. utilizing nonphospholipids and glycosphingolipids instead of phospholipids, enhancing expression of acid phosphatase to utilize organic P, and reallocating intracellular energy. Proteome responses of the P-deficient A. catenella to resupply of inorganic- and organic-P differed significantly, indicating different utilization pathways of inorganic and organic P, A. catenella might directly utilize low molecular weight organic P, such as G-6-P as both P and carbon sources.

Association of meteorological factors with pediatric intussusception in subtropical china: a 5-year analysis.

PURPOSE: The aim of this study was to determine whether climate factors correlate with variations in the rate of pediatric intussusception cases presenting to the Children's Hospital in Suzhou, China. MATERIAL AND METHODS: The hospital records of 5,994 pediatric cases of intussusception who had presented between Aug 2006 and Dec 2011 were retrospectively analyzed. Demographic data and air enema reduction data were collected for each case. RESULTS: The monthly rate of new intussusception cases fluctuated throughout the year generally rising from April to September with a peak from May to July. This annual cycling of intussusception incidence was highly significant over the 5 year observation period. Poisson regression analysis showed that the monthly number of intussusception cases was associated with an increase in mean temperature per month (P = 0.0001), sum of sunshine per month (P<0.0001), precipitation per month (P<0.0001), and was marginally associated with increased mean wind speed per month (P = 0.0709). CONCLUSION: The incidence of intussusception in Suzhou was seasonally variable with a peak in cases presenting during hotter, sunnier, and wetter months demonstrating a positive association with certain climatic factors.

[Practice on the case-based teaching innovation of Science of Meridians, Collaterals and Acupoints].

The case-based teaching method which is applied to the teaching of Science of Meridians, Collaterals and Acupoints is discussed in this paper, in which the typical cases such as the growth of the acupuncture-moxibustion eminent physicians, the application of acupoints by the eminent physicians and the experiences in the acupoint combination are integrated. The students are instructed to launch the clinical practical activity through establishing the clinical base of Science of Meridians, Collaterals and Acupoints, in association with the true cases. It is proved that the case-based teaching method can promote the training of the manipulation techniques of the students and the inheritance of the experiences of eminent physicians in higher education.

Antifungal activity of crude extracts and fat-soluble constituents of Holotrichia diomphalia larvae.

In this study, chemical compositions of fatty oils and bioactivity of crude extracts from Holotrichia diomphalia larvae as Chinese materia medica were investigated for the first time. The chemical compositions of the fatty oils were obtained by two different methods and determined by GC/MS. In total, the petroleum ether extract produced 21 compounds (96.3%) while the supercritical fluid extract produced six compounds (99.53%) for identification. The effect of petroleum ether and other crude extracts on Pyricularia oryzae was also examined. Results indicated that ethanol and petroleum ether extracts had excellent antifungal activities. These findings demonstrated that fatty oils from H. diomphalia larvae had great potential to be used as a source for natural health products.

[Pathogenicity of fungi isolated from American ginseng seeds and bioassay of fungicides against the pathogenic fungi].

OBJECTIVE: Detect the pathogenicity of fungi isolated from American ginseng seeds and select new fungicides against the pathogenic seed-born fungi. METHOD: inoculate the isolates to American ginseng seedlings to detect the pathogenicity, and seeded the hyphae disk at the center of agar plate containing chemicals to do fungicide bioassay. RESULT: Fusarium sp. isolate 5 and Alternara sp. isolate 13 had pathogenicity to American ginseng seedling. Sportak had the strongest inhibition to the two isolates, Carbendazim had better inhibition and Celest had weak inhibition. CONCLUSION: Sportak and Celest could be used as efficacious candidate chemicals to treat or coat the American ginseng seeds, and substitute Carbendazim, which has been used for many years, to control the diseases occurring in seedling stage of American ginseng.

[Fungal detection of American ginseng seeds from Beijing and northeast area in China].

OBJECTIVE: The quantity and genus of fungi on 13 samples of American ginseng seed from Beijing and Northeast area in China were detected. METHOD: Washing and surface sterilization were used to isolate the fungi existed on seed surface and inside of the seed, respectively. RESULT: The genera of the fungi in embryo and shell of the seeds mainly belonged to Fusarium spp., Alternaria spp., Penicilium spp., Cephalosporium sp., Rhizopus spp., and a small quantity of Mucor, Aspergillus, Tritroderma, Doratomyces and so on. The isolated fungal frequencies on the shell and in the embryo were 36%-100% and 40%-100% respectively. CONCLUSION: The fungal frequency of American ginseng seed was higher. There were significant differences among different seed samples, the main fungal genera and isolation frequency in the seed embryo were identical with the results from the seed shell.