Phosphorus Acid Research Articles

Cerebrovascular disease: how serum phosphorus, vitamin D, and uric acid levels contribute to the ischemic stroke

BackgroundAssociations between serum phosphorus level and the incidence of ischemic stroke are not clear. This study aimed to measure serum phosphorus, vitamin D3, and uric acid levels in ischemic stroke patients compared to a population without ischemic stroke.MethodsIn this cross-sectional study, 133 patients admitted to a neurology ward with the diagnosis of ischemic stroke were compared with a control group comprising 133 age- and gender-matching individuals. The presence of ischemic stroke was confirmed by a neurologist based on clinical signs, symptoms, brain CT scan, and MRI. Blood samples were taken from all patients in the first 24 h of admission to measure serum phosphorus, vitamin D3, calcium, and uric acid levels.ResultsAccording to the results of this study, uric acid medians in patients with stroke and controls were 4.9 [3.8–6.4] and 3.9 [3.5–4.9] mg/dL, respectively (p < 0.001). Median phosphorus and vitamin D levels were significantly lower in stroke patients than the controls (3.6 [3.02–4.21] vs. 4.2 [3.8–4.6]) and (15.1 [8.2–27.9] vs. 22.7 [10.4–39.2]), respectively. Multiple logistic regression analysis showed that the ischemic stroke was positively associated with the vitamin D level and negatively correlated with the uric acid level. The phosphorus level was not significantly predictive of ischemic stroke.ConclusionLower serum levels of vitamin D3 and higher levels of uric acid were associated with ischemic stroke. There are still unknowns about the role of these indicators on ischemic stroke and it requires further studies.

Synthesis of Metal-Organic Frameworks MIL-101(Cr)-NH2 Containing Phosphorous Acid Functional Groups: Application for the Synthesis of N-Amino-2-pyridone and Pyrano [2,3-c]pyrazole Derivatives via a Cooperative Vinylogous Anomeric-Based Oxidation.

In the current paper, we successfully developed and used metal–organic frameworks (MOFs) based on MIL-101(Cr)-NH2 with phosphorus acid functional groups MIL-101(Cr)-N(CH2PO3H2)2. The synthesized metal–organic frameworks (MOFs) as a multi-functional heterogeneous and nanoporous catalyst were used for the synthesis of N-amino-2-pyridone and pyrano [2,3-c]pyrazole derivatives via reaction of ethyl cyanoacetate or ethyl acetoacetate, hydrazine hydrate, malononitrile, and various aldehydes. The final step of the reaction mechanism was preceded by a cooperative vinylogous anomeric-based oxidation. Recycle and reusability of the described catalyst MIL-101(Cr)-N(CH2PO3H2)2 were also investigated.

Enhancement in the corrosion resistance behaviour of amorphous Ni[sbnd]P coatings by incorporation of graphene

In the current study, amorphous nickelphosphorusgraphene (NiPG) composite coatings were electroplated on mild steel substrate. Coatings were electroplated from nickel sulphate bath containing phosphorus acid and exfoliated graphene in amounts of 50 mg/l, 100 mg/l, 150 mg/l, and 200 mg/l. Phase constitution, composition, surface morphology and corrosion parameters were investigated as a function of the graphene content. Experimental results exhibited that NiP and NiPG composite coatings possessed improved corrosion resistance than the mild steel substrate and addition of graphene enhanced the corrosion resistance performance when compared to the pristine coating. It was observed that an optimum exists with respect to the amount of graphene dispersed in the electrolyte bath for achieving high anti-corrosion property from the coating produced using the respective plating bath. Lower amount of graphene in dispersion produced uniform surface morphology which acted along with the graphene impermeability to yield high corrosion resistance performance. Higher quantity of graphene in dispersion, on the other hand, caused their agglomeration thus producing rough and defective surface morphology which along with non-uniform distribution of graphene yielded higher corrosion rates.

Synthesis, characterization of a DOPO-based polymeric flame retardant and its application in polyethylene terephthalate

A high molecular weight DOPO-based flame retardant (DP-DE) containing phosphorus linked pendent groups was synthesized by a two-step esterification and polycondensation reaction, and characterized by Fourier transform infrared spectroscopy (FTIR), 13C nuclear magnetic resonance (13C NMR) and gel permeation chromatography (GPC). After added into polyethylene terephthalate (PET) via melt-blending method, the flame retardancy of DP-DE were monitored by thermo-gravimetric analysis (TGA), limiting oxygen index (LOI) and underwriter laboratories (UL-94) test. The results showed that DP-DE display good flame retardancy in PET. And the thermal stability, char residue yield and LOI values of the composites increased with the increase of DP-DE content. The flame retarded mechanism of DP-DE was investigated by pyrolysis-gas chromatogram-mass (PY-GC-MS), in situ FTIR, scanning electron microscope (SEM) and laser Raman spectroscopy (LRS). DP-DE was evidenced to release phosphorus acid and its derivatives, which catalyze carbonization and produce compact carbonaceous layers. Through protecting the polymeric materials substrate from further degradation and inhibiting the pyrolysis degree, both the amount and thermal stability of carbonaceous layers of DP-DE were improved, and hence enhancing the flame retarded performance of PET/DP-DE composites.

Microwave-assisted wet torrefaction of microalgae under various acids for coproduction of biochar and sugar

Wet torrefaction is a promising method to converts the high moisture microalgae to biofuel. In this study, the microalgae were torrefied in water or dilute acid solutions with the aid of microwaves irradiation. The reaction temperature and heating time were fixed at 160 °C and 10 min. The effects of sulfuric, phosphorus, and succinic acids on two different microalgae species (Chlorella vulgaris ESP-31 and FSP-E) were investigated. As a result, the disruption of the microalga FSP-E (high protein) was not notable in the acidic solution. The higher heating value of wet torrefied microalga ESP-31 (high carbohydrate) in succinic acid was enhanced up to 40% with at least 45% of energy yield. The use of 0.1 M of phosphorus acid in wet torrefaction produced the highest ash content of 1.61 and 11.60 wt% for microalgae ESP-31 and FSP-E, respectively. Thermogravimetric analysis revealed that the carbohydrate content of microalga ESP-31 has the highest degradation in sulfuric acid solution. In contrast, crystalline cellulose in the microalgae is hardly affected by the wet torrefaction process in low-temperature acidic solution. In terms of liquid product, a maximum glucose extraction of 35.39 g/L occurred with the use of 0.1 M of sulfuric acid. In conclusion, biochar produced using organic acid is desirable as solid fuel, whereas the use of sulfuric acid is more suitable to produce sugar for bioethanol production.

Weed Interference in Soybean Crop Affects Soil Microbial Activity and Biomass

ABSTRACT: Weeds and microorganisms interacting with their rhizosphere may influence nutrient absorption, which is an important factor for plant competition. The purpose of this study was to evaluate the microbiological activity, inorganic phosphorus solubilization (Pi) and acid phosphatase in the cultivated soil, in a combination of soybean (Glycine max) plants and weeds. Soybeans were cultivated in monoculture and in competition with Bidens pilosa, Brachiaria decumbens (Syn. Urochloa decumbens) and Eleusine indica, under two conditions: a) plants competing without contact between the roots b) plants competing with contact between the roots. A nylon screen with a 50 µm mesh was added to prevent contact between the roots of the species in competition so that the substratum could be separated in the vase. The experiment was conducted in randomized blocks, with four replications. The soybeans in competition with weeds led to lower oxidation of organic matter per unit of microbial biomass, resulting in a lower metabolic quotient, compared with the soybean monoculture. The contact between soybean roots and B. pilosa, B. decumbens and E. indica maintained a strong influence, raising the solubilization of Pi, respectively valued at 51, 39 and 31% in relation to the cultivation of each species with a nylon screen. Microbiological activity, inorganic phosphorus solubilization and acid phosphatase were altered by plant species, combinations of weeds and soybean plants in competition; by root contact in some cases. Thus, the microbiological activity of the soil can influence competition strategies and plant development.

Determination of the efficacy of monensin capsule (continuous release capsule) on metabolic parameters in transition dairy cows

Monensin is an ionophore antibiotic that changes the population of rumen bacteria. The aim of this study was to determine the effects of monensin controlled capsule administered 3 wk before calving on blood metabolites (serum beta-hydroxybutiric acid (BHBA), cholesterol (CHOL), urea, creatinine (CREA), gamma glutamyl transferase (GGT), aspartate aminotransferase (AST), total protein (TP), phosphorus (P), magnesium (Mg+), calcium (Ca++), glucose (GLU) and plasma non-esterified fatty acids (NEFA) concentration) and milk yield in the pre and post-calving term. 50 Holstein-Friesian cows were selected from the same flock. Blood samples were taken 3 weeks before the expected calving date and during weeks 1, 2, 4, 6 and 8 post calving. Cows were divided into two group: a study group (Group M, n:40) and a control group (Group C, n: 10). The group M orally received a cylindrical device (Kexxtone, ELANCO Animal Health, Guelph, ON, Canada) and the group C received no treatment. BHBA and NEFA was lower (P˂0,.05) in group M compared with group C in the 6 and 8 week post-calving. GLU was higher (P˂0.05) in group M compared with group C in the 4 week post-calving. Urea was higher (P˂0.05) in group M compared with group C in the 1 week post-calving. There was no statistically difference between two groups (P˂0.05) in milk yields. Although milk yield was similar in both groups, the change in concentration of BHBA, NEFA, GLU and urea showed that monensin CRC could be as a glycogenic precursor.

Potentiality of Sugarcane Juice and Jaggery for Immunity and Employment Generation in COVID-19 Pandemic Situation

In India, more than 65% people live in rural areas. Majority of the rural population suffers under nutrition or malnutrition as the Indian diet is deficient in nutrition. Sugarcane juice contains high amount of Vitamin B1, Vitamin B2, Vitamin B6, Vitamin C and inorganic salts such as iron, phosphorus, calcium and organic acids such as fumaric acid, succinic acid, citric acid and malic acid. It can be consumed as an energy drink, prevent cancer-especially prostate and breast cancer as flavonoids in sugarcane juice inhibits the growth of cancer cells in the milk glands and safe against pregnancy. Jaggery contains lot of vitamins(Vitamin A,B1,B2,B5,B6,C,D2 etc ), minerals(Calcium, magnesium, phosphorus, iron, manganese, zinc etc), protein, energy etc. It is popularly known as the “Medicinal Sugar”. It has been used as a sweetener in Ayurvedic medicine for 3000 years. Indian Ayurvedic medicine considers jaggery to be beneficial in treating throat and lung infections. Huge migrant labourers back to their home in lockdown situation after losing their jobs. So, unemployment problem is a major issue in current pandemic situation. To resolve the issues of unemployment and immunity, the current article briefly describe about the potentiality of sugarcane juice and jaggery in creating employment coupled with boosting up the immunity in COVID-19 pandemic situation and its business, which are most appropriate for major portion of West Bengal as well as in India particularly in the rural areas to support the rural health and economy for sustainable development.

Вплив Дерозалу на обмін азотистих та фосфорних сполук у печінці і м’язовій тканині курей за умов хронічного експерименту

Pesticides are toxic chemicals which are widely used as an effective means against pests and plant diseases as well as for animals’ protection against ectoparasites. They are also used to control rodents which transmit infectious diseases to people and animals (encephalitis, malaria, leptospirosis, rabies, listeriosis, etc.). Biosynthesis of protein in tissues depends on many circumstances and, first of all, on the complete set of amino acids, the state of enzymes’ system and on the presence of stimulators and inhibitors of synthesis reaction. Xenobiotics including benzimidazole derivatives are a part of these compositions. In Ukraine there are more than 20 medicines based on carbendazim. Thus, the analysis of the its influence on protein metabolism is relevant. In the research the hens breed Rhode Island of the 38th line for egg and meat of 30 days of age, with the mass 1000-1200 gr. was used. They were divided into 2 groups - test (n=36) and 1 control (n=18). Нens were equally cared and fed with two food allowances: the first part up to 40 days of age and the second part from 40 days of age up to the end of the experiment (60 days). Every day throughout 60 days hens of the first and second testing groups received feed with the medicine Derosal (BAYER, Germany) in the form of 50 % aqueous suspension in dose of 90 and 900 mg. per 1 kg of body mass (0.01 and 0.1 LD50 for hens) accordingly. The control group of hens was fed without addition of the medicine. The research was carried out on the 30th and 60th day. During the experiment it was found that addition of carbendazim to fodder slowed down the use of its nutrients. This situation was characterized by the fact that on the 30th and 60th day of the research the decrease of body mass gaining up to 10 % occurred, the decrease of protein and non-protein nitrogen content in liver and muscles in all the hens’ groups occurred. The increase of concentration of DNA and RNA phosphorus, the content of acid-soluble phosphate, phosphorus of phospholipid as well as lipoid phosphorus that indicates the slight deceleration of protein synthesis were determined, DNA and RNA in liver and hens’ muscles, also indicated the stimulation of synthesis of phosphorus acid ether and the reaction of glycolysis under the conditions of pesticide adding.&nbsp

Alkaline phosphatase-harboring bacterial community and multiple enzyme activity contribute to phosphorus transformation during vegetable waste and chicken manure composting.

The objective of this study was to evaluate changes in phosphorus fractions during vegetable waste and chicken manure composting. High throughput sequencing, quantitative PCR, and multiple analysis methods were applied to investigate interconnections among phosphorus fractions, enzyme activity, and phoD-harboring bacterial community composition. We found the highest composting temperature reached 61°C and phosphorus fractions presented significant differences during a 60-day composting. The content of plant-absorbable phosphorus, including water soluble phosphorus, available phosphorus, and citric acid phosphorus increased by 121%, 87%, and 63%, respectively. Additionally, phoD gene abundance significantly correlated with the activities of nine enzymes. Our findings emphasize that microbial activity plays an important role in phosphorus transformation during composting, and the final composting product could be good biological phosphorus fertilizer. To our knowledge, this is the first report indicating that enzyme activity, community composition and abundance of phoD-harboring bacteria have direct and indirect effects on phosphorus transformation during composting.

New synthesis of trimethylsilyl esters of phosphorus(III) acids

A novel synthetically important reaction has been developed for the quick, convenient, and high-yield preparation of trimethylsilyl esters of phosphorus(III) acids, synthetically valuable Michaelis–Arbuzov reaction precursors. Commercially and synthetically available initial compounds used are derivatives of propan-2-ol phosphorylated in the second position capable of long-term storage and available silylating reagents: hexamethyldisilazane, bis(trimethylsilyl)acetamide, and diethyl(trimethylsilyl)amine. Also, a stepwise reaction scheme of the starting compounds with silylating reagents has been proposed.

Synthesis and application of melamine-based nano catalyst with phosphonic acid tags in the synthesis of (3´-indolyl)pyrazolo[3,4-b]pyridines via vinylogous anomeric based oxidation

A novel nanostructured melamine-based organo solid acid with phosphorus acid tags was designed, synthesized and fully characterized. The catalytic activity of the resulted melamine hexakis(methylene)hexakis(phosphonic acid) (MHMHPA) as a heterogeneous catalyst was also investigated via an one-pot reaction between cyanoacetylindole, 3-methyl-1-phenyl-1H-pyrazol-5-amine, and an aromatic aldehyde. (3´-Indolyl)pyrazolo[3,4-b]pyridines were produced in good yields under refluxing ethanol. The solid catalyst can be recovered easily and reused without a significant loss of its catalytic activity.

Calidad del ensilaje de avena forrajera (Avena sativaL.) conservado en tres diferentes tipos de silos artesanales

This research work was carried out in the “Uywa Illa” cattle ranch of the Huancollo Community of the Tiahuanacu Municipality,with the objective of evaluating the conservation in three types of silos (trench, heap and bag) on the quality ofoat silage (Avena sativa L.) at 90 days of conservation. The response variables were: organoleptic characteristics, chemicalcomposition, and nutrient conservation efficiency. The organoleptic analysis indicates 96% good quality silage fortrench, bag and 85% silos in heap type silo, while 4% was considered poor quality silage in trench, bag and 15% silos forheap type silo. For analysis of chemical composition data and nutrient conservation efficiency, the completely randomizeddesign was used. The analysis of variance (ANVA) for the content of crude protein, calcium, phosphorus, metabolizableenergy and lactic acid, was not significant, the conservation efficiency of crude protein and metabolizable energy theANVA was not significant.

2702 Tumor Lysis Syndrome in a Patient With Gastric Adenocarcinoma

INTRODUCTION: Tumor lysis syndrome (TLS), considered a hematologic emergency, is uncommonly seen with solid tumors. TLS is most often seen in the context of aggressive lymphomas, where cell turnover is high. We present a case of tumor lysis syndrome in a patient with gastric adenocarcinoma, as a complication of FOLFOX (5-fluorouracil, leucovorin, oxaliplatin) chemotherapy. CASE DESCRIPTION/METHODS: 48-year-old male with metastatic gastric adenocarcinoma (Figure 1), who received his first cycle of FOLFOX 4 days prior, presented to the emergency department with slurred speech and altered mental status. Vitals at presentation were normal. Systemic examination was remarkable for agitation and disorientation to time, place and person. He had no focal neurologic deficits and rest of the exam was unremarkable. CT scan of the head and EEG were unrevealing. Laboratory analysis was significant for an elevated creatinine, phosphorus and uric acid (Table 1 day 5). The pattern of electrolyte abnormalities and their development after recent chemotherapy was consistent with a diagnosis of chemotherapy-induced laboratory and clinical TLS. Patient was managed with aggressive IV fluids and rasburicase, following which, the electrolyte abnormalities resolved, and he improved clinically back to baseline. DISCUSSION: Tumor lysis syndrome occurs when tumor cells release their contents into the bloodstream, either spontaneously or in response to therapy, leading to hyperuricemia, hyperkalemia, hyperphosphatemia, and hypocalcemia. Complications include renal insufficiency, cardiac arrhythmias, seizures and death. Rapidly proliferating tumors like high-grade lymphomas and acute leukemias are predisposed to TLS. TLS occurs infrequently with solid tumors. TLS-associated mortality rate, with solid tumors, is around 35%; higher than that with hematologic malignancies. This is likely explained because prophylactic measures are implemented more often in hematological malignancies and less often in solid tumors. Our patient fulfilled the Cairo-Bishop criteria for grade II TLS. To our knowledge, there have been only nine cases of TLS secondary to gastric adenocarcinoma published in the literature. We present the first case of FOLFOX-induced TLS in a patient with gastric adenocarcinoma. This case highlights the importance of early recognition of TLS in patients with gastric cancer. Initiation of early treatment can reduce the high morbidity and mortality associated with this condition.

Influence of phosphorus on rice (&amp;lt;italic&amp;gt;Oryza sativa&amp;lt;/italic&amp;gt; L.) grain zinc bioavailability and its relation to inositol phosphate profiles concentration

The hidden hunger caused by grain zinc (Zn) deficiency in crop poses a potential threat to the health of nearly two billion people worldwide, especially in developing countries. In this study, the long-term phosphorus fertilizer experiment and in vitro detached rice panicle culture systems with varied phosphorus levels were conducted to investigate the effect of phosphorus on rice grain Zn bioavailability and its relation of grain inositol phosphates profiles (phytic acid related metabolic derivatives) concentration. In our results, compared with low phosphorus level, high phosphorus supply increased grain phytic acid phosphorus and total phosphorus concentration (mg g–1). Moreover, high phosphorus supply also increased different grain inositol phosphate profile concentrations (InsP1-6), especially for InsP4-6. On the contrary, grain Zn concentration decreased with phosphorus supply. Both the decrement of Zn and increment of phytic acid phosphorus induced by the higher phosphorus supply in rice grain led to the significant decrement of grain Zn bioavailability. In in vitro detached panicle culture system, the Zn bioavailability in P12 treatment decreased by 81.3% relative to P0 treatment. In conclusion, higher phosphorus input could significantly decrease grain Zn bioavailability through increased grain phytic acid phosphorus and inositol phosphates derivatives concentration, in addition to the decrement of grain Zn concentration.

Combining ethylene diamine tetraacetic acid and high voltage pulsed discharge pretreatment to enhance short-chain fatty acids and phosphorus release from waste activated sludge via anaerobic fermentation

High voltage pulsed discharge has proved to be an efficient method for waste activated sludge pretreatment, however, the energy consumption of this pretreatment is always high, which hindered the practical application. In the present study, a combined ethylene diamine tetraacetic acid and high voltage pulsed discharge pretreatment method was firstly proposed to enhance short-chain fatty acids and phosphate recovery from waste activated sludge via anaerobic fermentation. The results showed that, with combined pretreatment, the soluble chemical oxygen demand and protein levels reached the maximum values of 5,639.6 ± 574 mg/L and 635.3 ± 6.6 mg/L during hydrolysis process, which were approximately 3.2- and 2.2-folds higher than those of the control, the short-chain fatty acids levels in liquid increased to 4,181.2 ± 16.3 mg/L on day 5, which was approximately 2.5-fold higher than that of the control. The analysis of short-chain fatty acids composition showed that the short-chain fatty acids in combined pretreatment systems mainly consisted of acetic and propionic acids, accounting for 67.2% of the total, indicating that short-chain fatty acids obtained in this study were favorable carbon sources for denitrification. In addition, the phosphate level in combined pretreatment experiment was 304.8 mg/L after 5 days anaerobic fermentation, which was approximately 2.8-fold higher than that of the control, suggesting that the combined pretreatment enhanced phosphate release. The possible mechanism of the combined pretreatment could be that the chelation of metal ions by ethylene diamine tetraacetic acid not only disintegrated the extracellular polymeric substances of sludge, but also led to carbon source and phosphate release simultaneously, so that the cell disruption effect could be achieved with lower voltage by latter high voltage pulsed discharge. These results indicated that the combined pretreatment could be a promising and alternative method to recover phosphorus and short-chain fatty acids from waste activated sludge via anaerobic fermentation, with the energy cost of high voltage pulsed discharge being reduced greatly.

Protective Effects of Grape Molasses and Resveratrol Against DMBA Induced Oxidative Stress in Rat Ovarian Tissues

Objective: The polyphenolic compound, resveratrol (3, 4’, 5-trihydroxystilbene), trans-resveratrol is a natural phytoalexin that exists in many different foods such as grape peel and seed, peanut, mulberry and blueberry. Molasses is a natural food obtained by boiling and concentrating fruit juices known to be rich in minerals such as iron, phosphorus, potassium, sodium, calcium and magnesium, and phosphoric acid, formic acid, organic acids and some vitamins. Polyphenolic compounds are natural antioxidants and are known to have protective effects against tissue damage caused by reactive oxygen species (ROS). In this study, we aimed to investigate the protective effects of grape molasses and resveratrol on ovarian damage induced by 7, 12-dimethylbenz [a] anthracene (DMBA). Methods: A total of 42 old female Wistar Albino rats, aged 18 weeks were divided into six groups. 10 mg/kg DMBA was injected in the rats in DMBA group subcutaneously on day 0 and day 7 while grape molasses feed with 20% grape molasses was given along with DMBA application to the rats in DMBA + grape molasses group. Resveratrol was administered by subcutaneous injection at 10 mg/kg/day to the DMBA + Resveratrol group, while only feed with 20% grape molasses was given to the grape molasses group. Resveratrol was administered by subcutaneous injection at 10 mg/kg/day to the resveratrol group. Results: GSH activity between the control group and molasses group, DMBA and DMBA + molasses groups and the control group and the DMBA + grape molasses groups was found statistically significant. Regarding the NO activity, the difference between the DMBA and resveratrol groups, DMBA and DMBA + resveratrol groups and the grape molasses and resveratrol groups was found statistically significant. MDA activity between DMBA + resveratrol and DMBA + grape molasses groups, and DMBA + grape molasses and grape molasses groups was found statistically significant. Conclusion: Molasses as one of the most important nutrient sources of Eastern and Central Anatolia was observed to decrease ovarian tissue oxidative damage induced with DMBA compared to resveratrol.

Bioavailability of organic phosphorus in an eutrophic lake: Insights from an in-situ experiment

Abstract The bioavailability of organic phosphorus (Porg) in surface sediments of an eutrophic lake was studied in an in-situ experiment. On the temporal scale, soluble reactive phosphorus (SRP) in the surface water showed an initial decrease and then increased in western and middle parts of the lake. In contrast, the SRP remained about 0.22 mg L−1 throughout the year in the eastern area of the lake. Four Porg compounds, phosphonate, orthophosphate monoesters, phospholipids and deoxyribonucleic acid phosphorus, were detected using solution 31P nuclear magnetic resonance spectroscopy. Orthophosphate monoesters were the dominant Porg in the sediment extracts, higher than the orthophosphate diesters deoxyribonucleic acid phosphorus and phospholipids. The SRP and Porg showed obvious seasonal variations in different lake regions. The surface water SRP had a negative relationship with sedimentary Porg in the western and middle lake regions. From spring to autumn, SRP in the water column decreased while Porg in the surface sediment increased; from autumn to winter, SRP in the water column increased and Porg in the surface sediment decreased. According to aquatic metabolism, we inferred that excessive external phosphorus input was the “trigger” and the aquatic plants were the “pump” for Porg biogeochemical cycling in the shallow lake. Therefore, appropriate human intervention, such as the harvest of aquatic plants, is vital for eutrophication control in freshwater ecosystems.

High food quality increases infection of Gammarus pulex (Crustacea: Amphipoda) by the acanthocephalan parasite Pomphorhynchus laevis

Parasitism is an important process in ecosystems, but has been largely neglected in ecosystem research. However, parasites are involved in most trophic links in food webs with, in turn, a major role in community structure and ecosystem processes. Several studies have shown that higher nutrient availability in ecosystems tends to increase the prevalence of parasites. Yet, most of these studies focused on resource availability, whereas studies investigating resource quality remain scarce. In this study, we tested the impact of the quality of host food resources on infection by parasites, as well as on the consequences for the host. Three resources were used to individually feed Gammarus pulex (Crustacea: Amphipoda) experimentally infected or not infected with the acanthocephalan species Pomphorhynchus laevis: microbially conditioned leaf litter without phosphorus input (standard resource); microbially conditioned leaf litter enriched in phosphorus; and microbially conditioned leaf litter without phosphorus input but complemented with additional inputs of benthic diatoms rich in both phosphorus and eicosapentaenoic acid. During the 110 day experiment, infection rate, parasite load, host survival, and parasite-mediated behavioral traits implicated in trophic transmission were measured (refuge use, geotaxis and locomotor activity). The resources of higher quality, regardless of the infection status, reduced gammarid mortality and increased gammarid growth. In addition, higher quality resources increased the proportion of infected gammarids, and led to more cases of multi-infections. While slightly modifying the geotaxis behavior of uninfected gammarids, resource quality did not modulate the impact of parasites on host behavior. Finally, for most parameters, consumption of algal resources had a greater impact than did phosphorus-enriched leaf litter. Therefore, manipulation of resource quality significantly affected host–parasite relationships, which stressed the need for future research to investigate in natura the relationships between resource availability, resource quality and parasite prevalence.

Aluminum distribution heterogeneity and relationship with nitrogen, phosphorus and humic acid content in the eutrophic lake sediment

Increasing amount of aluminum (Al) gets into aquatic ecosystem through anthropogenic activity, but the knowledge about Al migration and relationships with sediments possessing different physico-chemical properties in eutrophic lakes is limited. Here, the Al migration rule and relationships with sediment nutritions in the Hangzhou West Lake, China was investigated, where a certain amount of residual Al-salts can enter because of the pre-treatment of the Qiantang River diversion project every day. Results revealed the obvious spatial distribution heterogeneity of Al in sediment vertical direction and horizontal direction following water flow. The Al content in sediment ranged 0.463–1.154 g kg−1 in Maojiabu Lake, and ranged 9.862–40.442 g kg−1 in Xiaonanhu Lake. Higher Al content distributed in upper layer sediment in lake with more disturbance. Total nitrogen (TN) contents were higher 0.917–3.387 mg g−1 and 0.627–0.786 mg g−1 in upper layer sediment than that in lower layer in Maojiabu Lake and Xiaonanhu Lake, respectively. Total phosphorus (TP) content ranged 0.779–2.580 mg g−1, in which IP and Fe/Al-P contributed 24.9–80.8% and 17.0–51.6%, respectively. Correlations between Al content with nutrition, humic acid (HA) etc. of sediment regionally varied in Maojiabu and Xiaonanhu Lake. Spatial distribution of Al-salt in eutrophic lakes closely related with the physico-chemical characteristics of nutrients, humus, human disturbance and water division parameters. Results provides new insight into Al-salts migration and references for Al-risk evaluating in eutrophic lakes.