C14 distribution in photosynthate of tomato as influenced by substrate copper and molybdenum level and nitrogen source

Summary The influence of nitrogen source and micronutrient treatment on the apportionment of C¹⁴ in alcohol extracts was studied in tomato. Plants were exposed at several stages of maturity to C¹⁴O₂ and the ethanol-soluble photosynthate fractionated into sugars, organic acids, and amino acids.Ammonium-treated plants had low levels of organic acids at all stages of maturity, suggesting a rapid conversion to amino acid residues. However, the addition of copper in the absence of molybdenum resulted in increased labelling of the organic acid fraction under nitrate nutrition. The amino acid fraction was reduced at some stages of growth under these conditions. This may indicate that copper interferes with the role of molybdenum in the enzymatic reduction of nitrate.Measurement of the total quantity of some individual free amino acids indicated more efficient utilization of these for protein synthesis in the presence of copper. On the other hand, assay of the C¹⁴-activity of individual free amino acids showed that degree of label bore little relation to micro-nutrient treatment.Plant Science Department and Botany Department, University of Connecticut. Scientific Contribution No. 116, Agricultural Experiment Station, University of Connecticut, Storrs. This paper is based on a portion of the senior author's Ph. D. thesis (University of Connecticut).     

Finding Hamiltonian paths in tournaments on clusters

This paper presents a general methodology for the communication-efficient parallelization of graph algorithms using the divide-and-conquer approach and shows that this class of problems can be solved in cluster environments with good communication efficiency. Specifically, the first practical parallel algorithm, based on a general coarse-grained model, for finding Hamiltonian paths in tournaments is presented. On any such parallel machines, this algorithm uses only (3log p+1), where p is the number of processors, communication rounds, which is independent of the tournament size, and can reuse the existing linear-time algorithm in the sequential setting. For theoretical completeness, the algorithm is revised for fine-grained models, where the ratio of computation and communication throughputs is low or the local memory size, , of each individual processor is extremely limited for any , solving the problem with O(log p) communication rounds, while the hidden constant grows with the scalability factor 1/∊. Experiments have been carried out on a Linux cluster of 32 Sun Ultra5 computers and an SGI Origin 2000 with 32 R10000 processors. The algorithm performance on the Linux Cluster reaches 75% of the performance on the SGI Origin 2000 when the tournament size is about one million. Computational resources and technical support are provided by the Center for Computational Research (CCR) at the State University of New York at Buffalo. Chun-Hsi Huang received his Ph.D. degree in Computer Science from the State University of New York at Buffalo in 2001. His is currently an Assistant Professor of Computer Science and Engineering at the University of Connecticut. His interests include High Performance Parallel Computing, Cluster and Grid Computing, Biomedical and Health Informatics, Algorithm Design and Analysis, Experimental Algorithms and Computational Biology. Sanguthevar Rajasekaran received his Ph.D. degree in Computer Science from Harvard University in 1988. Currently he is the UTC Chair Professor of Computer Science and Engineering at the University of Connecticut and the Director of Booth Engineering Center for Advanced Technologies (BECAT). His research interests include Parallel Algorithms, Bioinformatics, Data Mining, Randomized Computing, Computer Simulations, and Combinatorial Optimization. Laurence Tianruo Yang received is Ph.D. degree in Computer Science from the Oxford University. He is currently a professor of Computer Science of the St. Francis Xavier University in Canada. His research interests include high-performance computing, embedded systems, computer archtecture and high-speed networking. Xin He received his Ph.D. degree in Computer Science from the Ohio State University in 1987. He is currently Professor of Computer Science and Engineering at the State University of New York at Buffalo. His research interests include Algorithms, Data Structures, Combinatorics and Computational Geometry.     

Book reviews

Book reviewed in this article: Dreyer, Glenn D. & Niering, William A. 1995. Tidal marshes of Long Island Sound: Ecology, history and restoration. 72 pp. Connecticut College Arboretum Bulletin No. 34. Published by the Connecticut College Arboretum, Box 5201 Connecticut College, 270 Michigan Avenue, New London, CT 06320–4196, USA. ISBN 1–878899–05–8 (paper). Price USD 5.-. Jerry M. Baskin ^{1 1} School of Biological Sciences, University of Kentucky, Lexington, KY, 40506-0225, USA.     

Notes On The Occurrence Of Clathrus Cancellatus,Tournf., In Argyllshire

Background: Estuaries are characterised by salinity gradients and regular flooding events. These environmental factors form stress gradients, along which species composition changes.

Aims: Analyse and compare patterns of plant species diversity along the estuarine salinity and flooding gradients of the Elbe and Connecticut Rivers.

Methods: Vegetation was sampled at three elevations (low, mid, high) in five sites of each marsh type (fresh, brackish, salt) in both estuaries. Patterns of species density (SD) and evenness (E) along the gradients were analysed and compared between the two estuaries with three-factor ANOVAs.

Results: The regional species pool was 33% higher for the Connecticut than for the Elbe. SD of fresh marshes (19 ± 2.2) was more than twice in the Connecticut than in the Elbe. We found an overall increase in SD from low to high elevation and from salt to freshwater marshes in both estuaries. However, SD and E were strongly depressed at intermediate elevations in the Elbe fresh and brackish marshes.

Conclusions: Although diversity patterns in the two estuaries show overall similarities, patterns of SD and E differ, when particular elevational zones and marsh types are compared. We hypothesise this to be due to evolutionary and historical influences on the regional species pools, shaping the impact of local biotic and abiotic processes.     

Dietary habits,nutrition and esophageal cancer: A case-control study on Kazakhs in Xinjiang

ObjectiveTo explore associations between dietary habits and esophageal epithelial cell carcinoma (ESCC) and provide a potential direction for exploring how different dietary habits and nutrient intake might affect ESCC development.Methods198 ESCC cases and 200 controls on Kazakhs were recruited in Xinjiang from 2010 to 2019 for a group-matched case-control study. The case group were recruited from the First Affiliated Hospital of Xinjiang Medical University and Affiliated Cancer Hospital of Xinjiang Medical University. The control population were recruited from two parts: hospital-based control and population-based control. The diagnosis was confirmed by histological examination. The food frequency questionnaire was used to investigate the dietary nutrients intake. Folic acid, vitamin B12, and DNA-methyltransferase 1(DNMT1) levels were measured in serum samples obtained from cases and controls.ResultsThe cholesterol intake of ESCC group was significantly higher than that of the control group while the intakes of protein, thiamin, riboflavin, folic acid, vitamin A, B6, C and E were significantly lower than the control group. Factors including lacking fresh vegetables and fruits, low educational level, low income, alcohol drinking, eating solid and dry food and smoked meat, dieting irregularly, salty taste preference, low serum folic acid level and high serum DNMT1 level were associated with increased risk of ESCC in Kazakhs.ConclusionDietary habits and nutrient intake were associated with increased risk of ESCC in Kazakhs that may provide a potential direction for further studies.     

Optical recording of activity in the hamster gustatory cortex elicited by electrical stimulation of the tongue

Having been informed by the Dean of the School of Dental Medicineat the University of Connecticut Health Center that some ofthe data reported in the above article has been found to befabricated, the Editors of Chemical Senses hereby retract thispaper and discourage citations of it.     

EXPLORING PORPHYRA SPECIES FOR USE AS NITROGEN SCRUBBERS IN INTEGRATED AQUACULTURE

Carmona, R.¹, Kraemer G. P.², Zertuche, J. A.³, Chanes, L.⁴, Chopin, T.⁵, Neefus C.^4,6 & Yarish, C.^{1 1}Dept. of Ecol. and Evol. Biol., University of Connecticut, One University Place, Stamford, CT 06901, USA; ²Department of Environmental Sciences, State University of New York, Purchase, NY 10577 USA; ³IIO, Universidad Autonoma de Baja California. Ensenada,B.C., Mexico; ⁴DGETI-CBTis41, Mexico; ⁵CCSA, Dept. of Biol., University of New Brunswick, Saint John, N.B., E2L 4L5, Canada; ⁶Department of Plant Biology, University of New Hampshire, Durham, NH 03824, USA Finfish mariculture along the Northeast US coast continues to develop into a strong industry. At a regional level, mariculture can be a significant contributor to nutrient loading in coastal waters. Since macroalgae are able to concentrate nutrients and grow at high rates, they can be an useful tool for alleviating this problem. In addition, seaweed mariculture is by itself a multi-billion dollar industry, with the red alga Porphyra (nori) valued at over $US 1.8 billion. Local species and strains of Porphyra from the Northeast U.S.A. are being studied to determine their capacity as nutrient scrubbers under different nutrient and temperature conditions. P. purpurea was grown under two N sources (NO3- vs. NH4+). The fastest growth (up to 13% d-1) and greatest N content (ca. 7% DW) were measured in plants grown at 300 µM NH4+. Short-term NH4+ uptake by P. purpurea (strains from Maine and Long Island Sound) and by P. amplissima was not saturated at 150 µM, the highest concentration tested. The P. purpurea isolate from Maine took up NH4+ faster than did the Long Island Sound isolate. NH⁴⁺ uptake by P. amplissima was faster than uptake by either P. purpurea strain. The high growth rates obtained and the ability for N uptake and tissue accumulation make these species suitable for using as a biological nutrient removal system.     

UNDERUTILIZED TOOLS: SEAWEEDS AS BIOREMEDIATION AND DIVERSIFICATION TOOLS AND BIOINDICATORS FOR INTE-GRATED AQUACULTURE AND COASTAL MANAGEMENT

Chopin, T.¹, Yarish, C.², Neefus, C.³, Kraemer, G. P.⁴, Belyea, E.¹, Carmona, R.², Saunders, G. W.⁵, Bates, C.⁵, Page, F.⁶ & Dowd, M.^{6 1}University of New Brunswick, Centre for Coastal Studies and Aquaculture and Centre for Environmental and Molecular Algal Research, P.O. Box 5050, Saint John, New Brunswick, E2L 4L5, Canada; ²University of Connecticut, Department of Ecology and Evolutionary Biology, 1 University Place, Stamford, Connecticut, 06901-2315, USA; ³University of New Hampshire, Department of Plant Biology, Office of Biometrics, G32 Spaulding Life Science Center, Durham, New Hampshire, 03824, USA; ⁴State University of New York, Purchase College, Division of Natural Sciences, Purchase, New York, 10577, USA; ⁵University of New Brunswick, Centre for Environmental and Molecular Algal Research, P.O. Box 4400, Fredericton, New Brunswick, E3B 5A3, Canada; ⁶Department of Fisheries and Oceans, Biological Station, 531 Brandy Cove Road, St. Andrews, New Brunswick, E5B 2L9, Canada On a regional scale, finfish aquaculture can be one of the significant contributors to coastal nutrification. Contrary to common belief, even in regions of exceptional tidal and apparent “flushing” regimes like the Bay of Fundy, water mixing and transport may be limited and water residency time can be locally prolonged. Hence, nutrient bio-availability remains significant for a relatively long period of time in some areas. Understanding the assimilative capacity of coastal ecosystems under cumulative pressure, then, becomes critical. To avoid pronounced shifts in coastal processes, conversion, not dilution, is the solution by integrating fed aquaculture (finfish) with organic and inorganic extractive aquaculture (shellfish and seaweed) so that the “ wastes” of one resource user become a resource for the others. Such a bioremediative approach provides mutual benefits to co-cultured organisms, and economic diversification and increased profitability per cultivation unit for the aquaculture industry. These concepts will be discussed and illustrated by the results of our on-going projects and we will demonstrate that seaweeds can also be excellent bio-indicators of nutrification/eutrophication revealing symptoms of environmental stress and measuring the zone of influence of an aquaculture site. The aquaculture industry is here to stay in our “coastal scape”: it has its place in the global seafood supply and demand, and in the economy of coastal communities. To help ensure its sustainability, it needs, however, to responsibly change its too often monotrophic practices by adopting polytrophic ones to become better integrated into a broader coastal management framework.     

EFFECTS OF NITRATE AND PHOSPHATE DISCHARGE FROM A FERTILIZER PRODUCTION PLANT IN A FJORD

Pedersen, A.^1,2, Knutzen, J.², Walday, M.², Molvær, M.² & Johnsen, T.^{2 1}Department of Ecology and Evolutionary Biology, University of Connecticut at Stamford, Stamford, CT. 06901 U.S.A;. ²Norwegian Institute for Water Research, P.O.B. 173 Kjelsås, 0411 Oslo, Norway. “Hydro Agri Glomfjord” a fertilizer producer has been discharging large quantities of ammonium, nitrate and phosphate into Glomfjord (in northern Norway, N 66,48°, E 13,57°) since 1947. The effects of the nutrient load to the Fjord have resulted in classical eutrophication symptoms. Elevated nutrient levels have resulted in frequent plankton blooms and seasonally reduced O₂ levels in the deep-water bodies as well as an eradication of the normal littoral assemblages. The fucoid belt had been replaced by various green algae 6 km from the outlet and outward the fjord. The effect is only seen on the northern side of the Fjord. After some improvement in the discharge loads in the 1980's, the condition in the pelagic column improved with regard to plankton blooms and deep water O₂ concentration. The littoral communities didn't, show any indication of recovery and a pollution indication index based on algal composition, showed even increased eutrophication.     

Relationships among phosphorus, molybdenum and free-living nitrogen fixation in tropical rain forests: results from observational and experimental analyses

Biological nitrogen (N) fixation is the primary source of “new” N to unmanaged ecosystems, and recent analyses suggest that terrestrial N inputs via free-living N fixation may be more important than previously assumed. This may be particularly true in some tropical rain forests, where free-living fixation could outpace symbiotic N fixation to represent the dominant source of new N inputs. However, our understanding of the controls over free-living N fixation in tropical rain forests remains poor, which directly constrains our ability to predict how N cycling will respond to changing environmental conditions. Although both phosphorus (P) and molybdenum (Mo) availability have been shown to limit free-living N fixation rates in the tropics, few studies have simultaneously explored P versus Mo limitation or the potential importance of P × Mo interactions. Here, an archived set of foliar, litter, and soil samples from a Costa Rican tropical rain forest provided an opportunity to simultaneously assess the relative strength of P versus Mo relationships with free-living N fixation rates. We also conducted a short-term, full-factorial (P × Mo) litter incubation experiment to directly assess nutrient limitation, allowing us to explore P and Mo controls over free-living N fixation rates using both observational and experimental approaches. We previously showed that N fixation rates were positively correlated with P concentrations in all substrates and, using the archived samples, we now show that Mo concentrations correlated with N fixation only in canopy leaves (where total Mo concentrations were extremely low). Likewise, fertilization with P alone (and not Mo) stimulated leaf litter N fixation rates. Thus, our results suggest that P availability dominantly controls free-living N fixation at this site, and when taken with data from other studies, our results suggest that attempts to identify “the nutrient” that limits N fixation in “the tropics” may be misguided. Rather, nutrient controls over free-living N fixation appear to be more nuanced—and the true nature of nutrient limitation to N fixation likely varies over a variety of scales across the vast tropical rain forest biome.     

The effect of limestone,molybdenum and incubation upon the extractable molybdenum in soils of eastern Canada

Summary An incubation experiment was conducted on 3 soils with 3 levels of lime-stone and 2 levels of Mo in the laboratory. There was no change in the amount of exchangeable Mo in Culloden and O'Leary soils as affected by the various pH levels after different incubation periods. On Acadia soil, the amount of exchangeable Mo increased after 4 weeks; however, the lime levels had no effect. There was an increase in extractable Mo in response to added Mo. Contribution No.206, Research Branch, Canada Department of Agriculture, Box 1210, Charlottetown, P. E. I., Canada.     

LjMOT1, a high‐affinity molybdate transporter from Lotus japonicus,is essential for molybdate uptake,but not for the delivery to nodules

Molybdenum (Mo) is an essential nutrient for plants, and is required for nitrogenase activity of legumes. However, the pathways of Mo uptake from soils and then delivery to the nodules have not been characterized in legumes. In this study, we characterized a high‐affinity Mo transporter (LjMOT1) from Lotus japonicus. Mo concentrations in an ethyl methanesulfonate–mutagenized line (ljmot1) decreased by 70–95% compared with wild‐type (WT). By comparing the DNA sequences of four AtMOT1 homologs between mutant and WT lines, one point mutation was found in LjMOT1, which altered Trp²⁹² to a stop codon; no mutation was found in the other homologous genes. The phenotype of Mo concentrations in F₂ progeny from ljmot1 and WT crosses were associated with genotypes of LjMOT1. Introduction of endogenous LjMOT1 to ljmot1 restored Mo accumulation to approximately 60–70% of the WT. Yeast expressing LjMOT1 exhibited high Mo uptake activity, and the K_m was 182 nm . LjMOT1 was expressed mainly in roots, and its expression was not affected by Mo supply or rhizobium inoculation. Although Mo accumulation in the nodules of ljmot1 was significantly lower than that of WT, it was still high enough for normal nodulation and nitrogenase activity, even for cotyledons‐removed ljmot1 plants grown under low Mo conditions, in this case the plant growth was significantly inhibited by Mo deficiency. Our results suggest that LjMOT1 is an essential Mo transporter in L. japonicus for Mo uptake from the soil and growth, but is not for Mo delivery to the nodules.     

Construction of a prognostic immune signature for lower grade glioma that can be recognized by MRI radiomics features to predict survival in LGG patients

BackgroundThis study aimed to identify a series of prognostically relevant immune features by immunophenoscore. Immune features were explored using MRI radiomics features to prediction the overall survival (OS) of lower-grade glioma (LGG) patients and their response to immune checkpoints.MethodLGG data were retrieved from TCGA and categorized into training and internal validation datasets. Patients attending the First Affiliated Hospital of Harbin Medical University were included in an external validation cohort. An immunophenoscore-based signature was built to predict malignant potential and response to immune checkpoint inhibitors in LGG patients. In addition, a deep learning neural network prediction model was built for validation of the immunophenoscore-based signature.ResultsImmunophenotype-associated mRNA signatures (IMriskScore) for outcome prediction and ICB therapeutic effects in LGG patients were constructed. Deep learning of neural networks based on radiomics showed that MRI radiomic features determined IMriskScore. Enrichment analysis and ssGSEA correlation analysis were performed. Mutations in CIC significantly improved the prognosis of patients in the high IMriskScore group. Therefore, CIC is a potential therapeutic target for patients in the high IMriskScore group. Moreover, IMriskScore is an independent risk factor that can be used clinically to predict LGG patient outcomes.ConclusionsThe IMriskScore model consisting of a sets of biomarkers, can independently predict the prognosis of LGG patients and provides a basis for the development of personalized immunotherapy strategies. In addition, IMriskScore features were predicted by MRI radiomics using a deep learning approach using neural networks. Therefore, they can be used for the prognosis of LGG patients.     

Effects of nutrient amendments on modular growth,flowering effort and reproduction of snowbed plants

Background: There have been few studies on the effects on alpine flora and vegetation of an increase in nutrient availability. Two main potential sources of increased nutrient availability in alpine ecosystems are enhanced mineralisation caused by climate warming and atmospheric nitrogen deposition. Little is known on how life history traits of different species are related at individual and community levels to enhanced nutrient availability.

Aims: We investigated the effects of nitrogen and phosphorus addition on the modular growth, flowering and germination of four species: two snowbed specialists and two alpine generalists.

Methods: We established in a late snowbed at the Gavia Pass, Italian Alps, a factorial experiment with four fertiliser treatments (N, P, Low N+P, and High N+P) and an unfertilised control. Nutrients were applied in 2003–2006 and we recorded the number of modules per individuals, total number of flowers, number of flowers per flowering module, and calculated the percentage of flowering modules in 2005 and 2006, and counted the number of seedlings in 2006.

Results: The modular growth and flowering effort of the species appeared to be co-limited by N and P. The alpine generalists showed greater responses to fertilization in vegetative growth and flowering compared with snowbed specialists. The number of seedlings recorded indicated species-specific responses to nutrient addition.

Conclusions: Our results suggest that enhanced nutrient availability stimulates modular growth and flowering effort in responsive alpine generalist species. This, in turn, could lead to an increase in their abundance, leading to changes in community structure in snowbeds with enhanced nutrient availability.     

DNA-PKcs is activated under nutrient starvation and activates Akt,MST1, FoxO3a,and NDR1

BackgroundPresence of unperfused regions containing cells under hypoxia and nutrient starvation; contributes to radioresistance in solid human tumors. We have previously reported that cultured cells; under nutrient starvation show resistance to ionizing radiation compare with cells under normal; condition, and that nutrient starvation increases ATM activity, which causes cellular resistance to; ionizing radiation (Murata et al., BBRC2018). For further investigation of molecular mechanisms; underlying radioresistance of cells under nutrient starvation, effects of nutrient starvation on activity; of DNA-PKcs have been investigated because both DNA-PKcs and ATM belong to the PIKK family; and are required for DNA DSBs repair. In addition to DNA-PKcs, effects of nutrient starvation on; activities of FoxO3a and its regulators Akt, MST1 and AMPK have been investigated because FoxO3a; mediates cellular responses to stress and is activated under nutrient starvation.MethodsA human glioblastoma cell line, T98G was used to examine the effects of nutrient starvation on activities and expression of DNA-PKcs, Akt, MST1, FoxO3a, NDR1, and AMPK. To elucidate; signal transduction pathways for FoxO3a activation under nutrient starvation, we examined effects of; specific inhibitors or siRNA for DNA-PKcs or Akt on activities and expression of MST1, FoxO3, NDR1, andAMPK.ResultsUnder nutrient starvation, phosphorylations of DNA-PKcs at Ser2056, Akt at Ser473, MST at Thr183, FoxO3a at Ser413, NDR1 at Ser281 and Thr282, and AMPK at Thr172 were increased, which suggests their activation. Nutrient starvation did not affect expression of DNA-PKcs, Akt, MST1, or NDR1, with decreased expression of FoxO3a and increased expression of AMPK. Inhibition; of DNA-PK suppressed phosphorylation of Akt under nutrient starvation. Inhibition of DNA-PK or; Akt suppressed phosphorylations of MST1, FoxO3a, and NDR1 under nutrient starvation, which; suggests DNA-PKcs and Akt activate MST1, FoxO3a, and NDR1. Inhibition of DNA-PK did not; suppress phosphorylation ofAMPK under nutrient starvation.ConclusionOur data suggest that DN-PKcs is activated under nutrient starvation and activates AktMST1, FoxO3a, and NDR1.     

Eelgrass recovery after nutrient enrichment reversal

Mumford Cove, a 48 ha Connecticut embayment on Long Island Sound, has a history of excessive nutrient inputs and corresponding eutrophic conditions with concomitant eelgrass (Zostera marina L.) loss. From 1945 to 1987, a municipal wastewater treatment facility discharged into the cove. In 1987, when the wastewater outfall was diverted to another location, the cove supported a near monoculture of the green algae Ulva lactuca L., covering 74% of the bottom. By 1988, macroalgal areal cover in Mumford Cove had declined to 9%. When we first sampled the cove in 1992, Z. marina and Ruppia maritima L. were present. By 1999, areal distribution of Z. marina and R. maritima had expanded to cover a third of the bottom. Periodic summertime surveys from 2002 through 2004 indicated that Z. marina was present in approximately half of the cove; R. maritima was sparse. Fifteen years after termination of nutrient enrichment, this cove had recovered from 40 years of point source anthropogenic nutrient input, returning from an Ulva-dominated to a Zostera-dominated state.     

Dragon's blood extracts reduce radiation-induced peripheral blood injury and protects human megakaryocyte cells from GM-CSF withdraw-induced apoptosis

PurposeDragon's blood (DB), a Chinese traditional herb, was shown to have certain protective effects on radiation-induced bone marrow injury due to the presence of several phenolic compounds. The 50% ethanol extracts (DBE) were separated from DB by the methods of alcohol extracting-water precipitating. The protective effects of DBE on hematopoiesis were studied, particularly on megakaryocytes.Materials and methodsIn this study, we investigated the in vivo radioprotective effects of DBE on hematopoiesis and pathological changes using an irradiated-mouse model. Moreover, the protective effects and potential molecular mechanisms of DBE on megakaryocytopoiesis in vitro were explored in GM-CSF depletion-induced Mo7e cell model.ResultsDBE significantly promoted the recovery of peripheral blood cells in irradiated mice. Histology bone marrow confirmed the protective effect of DBE, as shown by an increased number of hematopoietic cells and a reduction of apoptosis. In a megakaryocytic apoptotic model, DBE (50 µg/mL) markedly alleviated GM-CSF withdrawal-induced apoptosis and cell-cycle arrest of Mo7e cells. DBE (50 µg/mL) also significantly decreased the ratio of Bax to Bcl-2 expression, inhibited the active caspase-3 expression. In addition, DBE could induce ERK1/2 phosphorylation in GM-CSF-depleted Mo7e cell, but not Akt.ConclusionsOur data demonstrated that DBE could effectively accelerate the recovery of peripheral blood cells, especially platelet. DBE attenuated cell apoptosis and cell cycle arrest through the decrease of Bax/Bcl-2 ratio and the reduction of active caspase-3 expression. The effect of DBE on Mo7e cells survival and proliferation is likely associated with the activation of ERK, but not Akt.     

Nutrient addition effects on chlorophyll a,phytoplankton biomass,and heterocyte formation in Lake Erie’s central basin during 2014–2017: Insights into diazotrophic blooms in high nitrogen water

1. Phosphorus (P) usually is the primary limiting nutrient of phytoplankton biomass, but attention towards nitrogen (N) and trace nutrients, such as iron (Fe), has surfaced. Additionally, N-fixing cyanobacterial blooms have been documented to occur in N-rich, P-poor waters, which is counterintuitive from the paradigm that low N and high P promotes blooms. For example, Lake Erie's central basin has Dolichospermum blooms when nitrate concentrations are high, which raises questions about which nutrient(s) are selecting for Dolichospermum over other phytoplankton and why an N-fixer is present in high N waters?
2. We conducted a 4-year (2014–2017) study in Lake Erie's central basin to determine which nutrient (P, N, or trace nutrients such as Fe, molybdenum [Mo], and boron [B]) constrained chlorophyll concentration, phytoplankton biovolume, and nitrate assimilation using nutrient enrichment bioassays. The enriched lake water was incubated in 1-L bottles in a growth chamber programmed at light and temperatures of in situ conditions for 4–7 days. We also quantified heterocytes when N-fixing cyanobacteria were present.
3. Compared to the non-enriched control, the P-enriched (+P) treatment had significantly higher chlorophyll and phytoplankton biovolume in c. 75% of experiments. Combination enrichments of P with ammonium-N, nitrate-N, Fe, Mo, and B were compared to the +P treatment to determine secondary limitations. +P and ammonium-N and +P nitrate-N resulted in higher chlorophyll in 50% of experiments but higher phytoplankton biovolume in only 25% of experiments. These results show that P was the primary limiting nutrient, but there were times when N was secondarily limiting.
4. Chlorophyll concentration indicated N secondary limitation in half of the experiments, but biovolume indicated only N secondary limitation in 25% of the experiments. To make robust conclusions from nutrient enrichment bioassays, both chlorophyll and phytoplankton biovolume should be measured.
5. The secondary effects of Fe, Mo, and B on chlorophyll were low (<26% of experiments), and no secondary effects were observed on phytoplankton biovolume and nitrate assimilation. However, +P and Fe resulted in more chlorophyll than +P in experiments conducted during Dolichospermum blooms, and +P and B significantly increased the number of heterocytes in Dolichospermum. These results indicate that low Fe availability might select for Dolichospermum, and low B constrains heterocyte formation in the central basin of Lake Erie. Furthermore, these results could apply to other lakes with high N and low P where diazotrophic cyanobacterial blooms occur.

     

A STUDY OF GENUS MYCOPHILA FELT FROM CHINA (DIPTERA: CECIDOMYIIDAE)

Abstract  Three species of the genus Mycophila Felt collected from China are reported in this paper; M. speyeri Barnes 1926 from Jiangsu Province, M. longispina Bu et Mo sp. nov. from Shandong Province and M. echinoidea Bu et Mo sp. nov. from Sichuan Province are new to science. The type material of M. longispina Bu et Mo is deposited in the Department of Plant Protection, Shandong Agricultural University, Taian, Shandong, that of M. echinoidea Bu et Mo is deposited in the Department of Biology, Nankai University, Tianjin.