Characterization of aminoalkylphosphonyl cerebrosides in muscle tissue of Turbo cornutus

From muscle tissues of the marine snail (Turbo cornutus) aminoalkylphosphonyl cerebrosides, which had been shown to be present in visceral parts, were isolated.Their structure was determined by degradative methods and by characterization of components by gas chromatography-mass spectrometry.The aminoalkylphosphonyl cerebroside fraction consisted of a major portion of 1-O-[6′-O-(N-methylaminoethylphosphonyl)galactosyl] ceramide and a minor portion of a novel lipid, 1-O-[6′-O-(aminoethylphosphonyl)galactosyl] ceramide.The fatty acids of the fraction were mainly palmitic (53.3%) and 2-hydroxy palmitic acid (14.6%). The long chain bases were mainly dihydroxy C_{22 : 2} (36.6%), C_{18 : 1} (14.6%) and C_{18 : 2} (11.3%), and trihydroxy bases were also found as minor components.     

Identification of diacylglycerol-O-(N,N,N-trimethyl)-homoserine in the halotolerant alga, Dunaliella parva

An unusual zwitterionic polar lipid component isolated from the halotolerant alga, Dunaliella parva Lerche, has been identified as 1(3),2-diacylglyceryl-3(1)-O-4′-(N,N,N-trimethyl) homoserine by means of infrared spectrometry, ¹H- and ¹³C-NMR spectrometry and field desorption mass spectrometry of the intact lipid, as well as by its TLC mobilities and staining behaviour. Mass spectrometry of this lipid indicated the presence of the following major molecular species: 16:0–18:0 (24%); 18:3–18:3 (19%); 16:0–18:2 (16%); 16:0–18:1 (8%).     

Bounds on the total population for species governed by reaction-diffusion equations in arbitrary two-dimensional regions

Analysis based on the integration of differential inequalities is employed to derive upper and lower bounds on the total populationN(t) = ∫ _R θ(x ₁,x ₂,t) dx ₁ dx ₂ of a biological species with an area-density distribution function θ=θ(x ₁,x ₂,t) (≥0) governed by a reaction-diffusion equation of the form ∂θ/∂t =D∇²θ +fθ −gθ ⁿ⁺¹ whereD (>0),n (>0),f andg are constant parameters, θ=0 at all points on the boundary ∂R of an (arbitrary) two-dimensional regionR, and the initial distribution (θ(_{x 1},x ₂, 0) is such thatN(0) is finite. Forg≥0 withR the entire two-dimensional Euclidean space, a lower bound onN(t) is obtained, showing in particular thatN(∞) is bounded below by a finite positive quantity forf≥0 andn>1. An upper bound onN(t) is obtained for arbitrary bounded or unbounded)R withn=1,f andg negative, and ∫ _R θ(x ₁,x ₂, 0)² dx ₁ dx ₂ sufficiently small in magnitude, implying that the population goes to extinction with increasing values of the time,N(∞)=0. Forg≥0 andR of finite area, the analysis yields upper bounds onN(t), predicting eventual extinction of the population if eitherf≤0 or if the area ofR is less than a certain grouping of the parameters in cases for whichf is positive. These results are directly applicable to biological species with distributions satisfying the Fisher equation in two spatial dimensions and to species governed by certain specialized population models.     

The lipid composition of the electric organ of the ray, Torpedo marmorata, with specific reference to sulfatides and Na+-K+-ATPase.

The lipids from the electric organ of the ray, Torpedo marmorata, have been isolated and characterized. The major lipids were cholesterol, choline phospholipids, ethanolamine phospholipids, and sphingomyelins. The major fatty acids of ethanolamine phospholipids were 18:1, 18:0, 22:6, and 20:4. More than 50% of the acids in choline phospholipids were 16:0. The sphingomyelins consisted of five major ceramide species, all with sphingosine and the fatty acids 14:0, 15:0, 16:0, 22:1, and 24:1. The fatty acid 15:0 was mostly branched (n-2), a fatty acid earlier identified in sphingomyelins of the rectal gland of spiny dogfish. All long-chain bases were dihydroxy bases with a small percentage of branched chains. Sulfatides (cerebroside sulfate) made up the largest glycolipid fraction. The polar moiety wase galactose-3-sulfate. The fatty acids were normal and 2-hydroxy; the homologue 24:1 was the most abundant in both types of fatty acids. Most fatty acids were higher homologues of mono-unsaturated acids, but normal 18:0 fatty acid was also found. The long-chain bases were both dihydroxy and trihydroxy, with very small amounts of branched chains. The two major ceramide species of sulfatides were sphingosine combined with normal and hydroxy 24:1 fatty acids, respectively. Smaller amounts of trihydroxy base (18:0) were found linked to hydroxy 24:1 fatty acid, but not to its normal homologue. The cerebrosides contained the two major species mentioned above but lacked the trihydroxy base-hydroxy fatty acid species. The ratio of the activity of Na+-K+-dependent ATPase (EC 3.6.1.3) and the concentration of sulfatides was similar to ratios found for other tissues with normal and increased Na+ and K+ transporting capacity. The significance of this finding is discussed.     

Synthesis, spectroscopic and structural characterization of the high-spin Fe(II) cyanato-N and thiocyanato-N “picket fence” porphyrin complexes

Two new iron(II) five-coordinated porphyrin complexes [Na(2,2,2-crypt)] [Fe^II(TpivPP)(NCO)] (1) (TpivPP = α,α,α,α-tetrakis(o-pivalamidophenyl) porphyrin known as picket fence porphyrin and 2,2,2-crypt is the cryptand-222) and [K(2,2,2-crypt)][Fe^II(TpivPP)(NCS)] (2) have been prepared and characterized. The UV-Vis and IR spectroscopic data are consistent with a cyanato-N and thiocyanato-N ferrous porphyrinates. The Mössbauer data and the X-ray structural analysis indicate that the Fe(II) cation in 1 and 2 is high-spin (S = 2) and has the (d_xy)²(d_xz)¹(d_yz)¹(d_z²)¹(d_x²-y²)¹ ground state electronic configuration.For complex 1, the average equatorial iron-pyrrole N bond length (Fe-N_p = 2.120(2) Å), the distance between the iron and the 24-atom mean plane of the porphyrin ring (Fe-P_C = 0.6805(7) Å) and the distance between the iron and the plane made by the four pyrrole nitrogens (Fe-P_N = 0.5923(12) Å) are longer than those of complex 2 and similar five-coordinated Fe(II) high-spin porphyrinates. This is probably due to the significant electronic repulsion of the d_x²-y² and d_xy orbitals by the negative charge of the pyrrole N atoms in case of 1.     

Effects of inorganic nitrogen forms on growth, morphology, nitrogen uptake capacity and nutrient allocation of four tropical aquatic macrophytes (Salvinia cucullata, Ipomoea aquatica, Cyperus involucratus and Vetiveria zizanioides)

This study assesses the growth and morphological responses, nitrogen uptake and nutrient allocation in four aquatic macrophytes when supplied with different inorganic nitrogen treatments (1) NH₄⁺, (2) NO₃⁻, or (3) both NH₄⁺ and NO₃⁻. Two free-floating species (Salvinia cucullata Roxb. ex Bory and Ipomoea aquatica Forssk.) and two emergent species (Cyperus involucratus Rottb. and Vetiveria zizanioides (L.) Nash ex Small) were grown with these N treatments at equimolar concentrations (500 μM). Overall, the plants responded well to NH₄⁺. Growth as RGR was highest in S. cucullata (0.12 ± 0.003 d⁻¹) followed by I. aquatica (0.035 ± 0.002 d⁻¹), C. involucratus (0.03 ± 0.002 d⁻¹) and V. zizanioides (0.02 ± 0.003 d⁻¹). The NH₄⁺ uptake rate was significantly higher than the NO₃⁻ uptake rate. The free-floating species had higher nitrogen uptake rates than the emergent species. The N-uptake rate differed between plant species and seemed to be correlated to growth rate. All species had a high NO₃⁻ uptake rate when supplied with only NO₃⁻. It seems that the NO₃⁻ transporters in the plasma membrane of the root cells and nitrate reductase activity were induced by external NO₃⁻. Tissue mineral contents varied with species and tissue, but differences between treatments were generally small. We conclude, that the free-floating S. cucullata and I. aquatica are good candidate species for use in constructed wetland systems to remove N from polluted water. The rooted emergent plants can be used in subsurface flow constructed wetland systems as they grow well on any form of nitrogen and as they can develop a deep and dense root system.     

Competition between Lemna minuta and Lemna minor at different nutrient concentrations

We investigated the differential responses of invasive alien Lemna minuta and native Lemna minor to nutrient loading as well as the mechanism of competition between the species. The role of nutrients, species identity, species influence in determining the outcome of competition between the species was estimated using the Relative Growth Rate Difference (RGRD) model. The two species differed in their response to nutrient loading. The native L. minor responded indifferently to nutrient loading. The species Relative Growth Rate (RGR) was 0.10 d⁻¹, 0.11 d⁻¹ and 0.09 d⁻¹ in high, medium and low nutrients, respectively. On the other hand, the invasive L. minuta responded opportunistically to high nutrient availability and had an RGR of 0.13 d⁻¹, 0.10 d⁻¹ and 0.08 d⁻¹ in high, medium and low nutrients, respectively. As a result, the invasive species was dominant in high nutrient availability but lost to the native species at low nutrient availability. The invader formed approximately 60% and less than 50% of the stand final total dry biomass in high and low nutrient availability, respectively. Species RGR were reduced by both intra- and interspecific competition but intraspecific effects were stronger than interspecific effects. On the overall, the species significantly differed in their constant RGR. These differences in RGR between the species (species identity) and the differential response to nutrient loading were the main determinant of change in final biomass composition of these species in mixture. Species influence (competition) only had a small influence on the outcome of competition between the species. The observed species response to nutrient loading could be targeted in management of the invasive species. Lowering nutrients can be proposed to reduce the impact of the invasive L. minuta.     

Mononuclear and tetranuclear palladacycles with terdentate [C,N,N] and [C,N,O] Schiff base ligands. C-H versus C-Br activation reactions

Reaction of the Schiff base ligands 2-Br-4,5-(OCH₂O)C₆H₂C(H)NCH₂CH₂NMe₂ (a) and 4,5-(OCH₂CH₂)C₆H₃C(H)NCH₂CH₂NMe₂ (b) with Pd(OAc)₂ or K₂[PdCl₄] leads to the mononuclear cyclometallated compounds [Pd{2-Br-4,5-(OCH₂O)C₆HC(H)NCH₂CH₂NMe₂-C6,N,N}(OCOMe)] (1a) and [Pd{4,5-(OCH₂CH₂)C₆H₂C(H)NCH₂CH₂NMe₂-C6,N,N}(Cl)] (1b), derived from C-H activation at the C6 carbon. Treatment of a with Pd₂(dba)₃ gave [Pd{4-5-(OCH₂O)C₆H₂C(H)NCH₂CH₂NMe₂-C2,N,N}(Br)] (2a), via C-Br activation.The metathesis reaction of 1a with aqueous sodium chloride gave [Pd{2-Br-4,5-(OCH₂O)C₆HC(H)NCH₂CH₂NMe₂-C6,N,N}(Cl)] (3a), with exchange of the acetate group by a chloride ligand. Treatment of the cyclometallated monomers 1a-3a with PPh₃ in a 1:1 molar ratio yielded the mononuclear complexes [Pd{2-Br-4,5-(OCH₂O)C₆HC(H)NCH₂CH₂NMe₂-C6,N}(L)(PPh₃)] (L: OAc, 4a; Cl, 5a) and [Pd{4-5-(OCH₂O)C₆H₂C(H)NCH₂CH₂NMe₂-C2,N}(Br)(PPh₃)] (6a), with Pd-NMe₂ bond cleavage. However, treatment of a solution of 3a or 2a with silver trifluoromethanesulfonate, followed by reaction with PPh₃ in acetone yielded the cyclometallated complexes [Pd{2-Br-4,5-(OCH₂O)C₆HC(H)NCH₂CH₂NMe₂-C6,N,N}(PPh₃)][CF₃SO₃] (7a) and [Pd{4-5-(OCH₂O)C₆H₂C(H)NCH₂CH₂NMe₂-C2,N,N}(PPh₃)][CF₃SO₃] (8a), respectively, where the Pd-NMe₂ bond was retained.The reaction of the ligands 2-Br-4,5-(OCH₂O)C₆H₂C(H)N(2′-OH-5′-^tBuC₆H₃) (c) and 4,5-(OCH₂CH₂)C₆H₃C(H)N(2′-OH-5′-^tBuC₆H₃) (d) with Pd(OAc)₂ gave the tetranuclear complexes [Pd{2-Br-4,5-(OCH₂O)C₆HC(H)N(2′-O-5′-^tBuC₆H₃)-C6,N,O}]₄ (1c) and [Pd{4,5-(OCH₂CH₂)C₆H₂C(H)N(2′-O-5′-^tBuC₆H₃)-C6,N,O}]₄ (1d), respectively. Treatment of 1c with PPh₃ in 1:4 molar ratio, gave the mononuclear species [Pd{2-Br-4,5-(OCH₂O)C₆HC(H)N(2′-(O)-5′-^tBuC₆H₃)-C6,N,O}(PPh₃)] (2c) with opening of the polynuclear structure after P-O_bridging bond cleavage.The structure of compounds 2a, 1c and 1d has been determined by X-ray diffraction analysis.     

Pseudoscardovia suis gen. nov., sp. nov., a new member of the family Bifidobacteriaceae isolated from the digestive tract of wild pigs (Sus scrofa)

Seventeen fructose-6-phosphate phosphoketolase-positive bacterial strains were isolated from the digestive tract of wild pigs (Sus scrofa). Most of them were identified as Bifidobacterium boum according to sequences of 16S rRNA gene. Two strains isolated from the small intestine content had unusual morphology of cells in comparison with bifidobacteria. Cells growing in liquid anaerobic media were regular shaped rods arranged mostly in pairs. These isolates showed relatively low 16S rRNA gene sequence similarities (maximum identity of 94%) to members of the family Bifidobacteriaceae. Nevertheless, phylogenetic analyses of 16S rRNA, hsp60 and xfp gene sequences revealed that these strains are more related to recently described Neoscardovia, Aeriscardovia and other scardovial genera, than to Bifidobacterium species. Partial gene sequences of other phylogenetic markers showed low (65.8–89.5%) similarities to genome sequences of bifidobacteria and Gardnerella vaginalis. The major fatty acids detected in cells of the representative strain DPTE4^T were C_16:0, C_18:1, C_14:0. The peptidoglycan type of the DPTE4^T strain was A3β l-Orn(l-Lys)-l-Ser(l-Ala)-l-Ala₂. Polar lipid analysis revealed two phosphoglycolipids and phospholipids, a glycolipid and diphosphatidylglycerol. The results of phylogenetic, genotypic and phenotypic analyses support the proposal of a novel taxa, Pseudoscardovia suis gen. nov., sp. nov. (type strain = DPTE4^T = DSM 24744^T = CCM 7942^T).     

Kinetic Changes in Free Ceramide and Cerebroside during Germination of Black Gram

Free ceramide and cerebroside were isolated from black gram sprouts of all germinating stages. Free ceramide and cerebroside were found to increase during germination.

The major sphingosine bases of free ceramide were 4-hydroxysphingenine and 4-hydroxy-sphinganine (trihydroxy type) while that of cerebroside was sphinga-4,8-dienine (dihydroxy type). A change in the component sphingosine base was that 4-hydroxysphingenine in free ceramide and cerebroside increased slightly after germination.

The major fatty acid of free ceramide was α-hydroxylignoceric acid while that of cerebroside was α-hydroxypalmitic acid. Changes in component fatty acid were that α-hydroxylignoceric acid in both sphingolipids increased after germination.     

Caulobacter zeae sp. nov. and Caulobacter radicis sp. nov., novel endophytic bacteria isolated from maize root (Zea mays L.)

Four bacterial strains designated 410^T, 441, 695^T and 736 were isolated from maize root in Beijing, P. R. China. Based on 16S rRNA gene phylogeny, the four strains formed two clusters in the genus Caulobacter. Since strain 441 was a clonal variety of strain 410^T, only three strains were selected for further taxonomic studies. The whole genome average nucleotide identity (ANI) value between strains 410^T and 695^T was 94.65%, and both strains shared less than 92.10% ANI values with their close phylogenetic neighbors Caulobacter vibrioides DSM 9893^T, Caulobacter segnis ATCC 21756^T and Caulobacter flavus CGMCC 1.15093^T. Strains 410^T and 695^T contained Q-10 as the sole ubiquinone and their major fatty acids were C_{16:0, 11-methyl C18:1ω 0}, 11-methyl C_{18: 1}ω7c, summed feature 3 (C_{16:1ω7c and/or C16:1ω 1}ω7c and/or C_{16: 1}ω6c) and summed feature 8 (C_{18:1ω7c and/or C18:1ω 1}ω7c and/or C_{18: 1}ω6c). Their major polar lipids consisted of glycolipids and phosphatidylglycerol, and phenotypic tests differentiated them from their closest phylogenetic neighbors. Based on the results obtained, it is proposed that the three strains represent two novel species, for which the names Caulobacter zeae sp. nov. (type strain 410^T = CGMCC 1.15991 = DSM 104304) and Caulobacter radicis sp. nov. (type strain 695^T = CGMCC 1.16556 = DSM 106792) are proposed.     

Synthesis and characterization of platinum(IV) complexes with N,S and S,S heterocyclic ligands

The reactions of [PtMe₃(OAc)(bpy)] (4) with the N,S and S,S containing heterocycles, pyrimidine-2-thione (pymtH), pyridine-2-thione (pytH), thiazoline-2-thione (tztH) and thiophene-2-thiol (tptH), resulted in the formation of the monomeric complexes [PtMe₃(-κS)(bpy)] ( = pymt, 5; pyt, 6; tzt, 7; tpt, 8), where the heterocyclic ligand is coordinated via the exocyclic sulfur atom. In contrast, in the reactions of [PtMe₃(OAc)(Me₂CO)_x] (3, x = 1 or 2) with pymtH, pytH, tztH and tptH dimeric complexes [{PtMe₃(μ-)}₂] (μ- = pymt, 9; pyt, 10; tzt, 11) and the tetrameric complex [{PtMe₃(μ₃-tpt-κS)}₄] (12), respectively, were formed. The complexes were characterized by microanalyses, ¹H and ¹³C NMR spectroscopy and negative ESI-MS (12) measurements. Single-crystal X-ray diffraction analysis of [PtMe₃(pymt-κS)(bpy)] (5) exhibited a conformation where the pymt ligand lies nearly perpendicular to the complex plane above the bpy ligand that was also confirmed by quantum chemical calculations on the DFT level of theory.     

Effects of insect cuticular fatty acids on in vitro growth and pathogenicity of the entomopathogenic fungus Conidiobolus coronatus

Eighteen fatty acids identified in the cuticle of three insect species representing differing susceptibilities to C. coronatus infection, were tested for effects on the in vitro growth and pathogenicity of the parasitic fungus. At all applied concentrations (0.1-0.0001% w/v) growth was inhibited by C_16:0, C_16:1, C_18:0, C_18:1, C_18:2, C_18:3, C_20:0 and C_20:1. At high concentrations spore germination was inhibited by C_7:0, C_8:0, C_9:0, C_10:0, C_12:0, C_18:2 and C_18:3 and hyphal growth was merely retarded by C_5:0, C_6:0, C_6:2, C_14:0, C_16:0, C_16:1, C_18:0, C_18:1, C_20:0 and C_20:1. The presence of C_15:0 at the 0.1% concentration stimulated growth of C. coronatus. Sporulation was inhibited by all concentrations of C_16:0 and C_18-20 fatty acids. Low concentrations of C_5:0, C_6:0, C_6:2 and C_7:0 enhanced sporulation. Fatty acids C_5-12 as well as C_18:3, C_20:0 and C_20:1 decreased the ability of fungal colonies to infect G. mellonella while C_16:1 elevated it thus suggesting that C_16:1 may stimulate production of enzymes involved in the host invasion. Toxicity of metabolites released into incubation medium decreased with varying degrees in the presence of C_6:0, C_6:2, C_7:0, C_9:0, C_12:0, C_16:1, C_18:2, C_18:3, C_20:0 and C_20:1; other fatty acids had no effect. Further work is needed to analyse the effects of exogenous fatty acids on the C. coronatus enzymes implicated in fungal pathogenicity as well as on the production of insecticidal metabolites.     

Electronic absorption and MCD spectra for octacyanometallate complexes M(CN)8, M=Mo(IV), W(IV), n=4 and Mo(V), W(V), n=3

Electronic absorption and 8.0 T magnetic circular dichroism (MCD) spectra are reported for M(CN)₈ ⁴⁻, M=Mo(IV) and W(IV), in aqueous solution and M(CN)₈ ³⁻, M=Mo(V) and W(V), in acetonitrile solutions. In addition some absorption and MCD spectra are reported for the M(CN)₈ ³⁻ ions embedded in thin poly methyl methacrylate (PMMA) plastic films at temperatures from 295 to 10 K. The temperature dependence of the MCD spectra confirms the presence of C terms. The solution and PMMA spectra for the both Mo and W complexes in either the IV or V oxidation states are remarkably similar to each other for the same oxidation state and are interpreted within a D_2d structural framework for the isotropic environment. The weak bands below 3.0 μm⁻¹ (1 μm⁻¹=10⁴ cm⁻¹) for the M(IV) complexes are assigned as metal-localized ligand field (LF) transitions. LF transitions are also suggested for weaker unresolved absorption between 3.0 and 3.6 μm⁻¹ for the M(V) ions. The intense bands above 3.6 μm⁻¹ for M(IV) and 4.6 μm⁻¹ for M(V) complexes are interpreted as metal to ligand charge transfer (MLCT) from the metal b₁(x²−y²) HOMO to CN⁻-based π * orbitals. The prominent intense bands observed below 4.5 μm⁻¹for the M(V) complexes are assigned as ligand to metal charge transfer (LMCT) from occupied non-bonding or weakly π bonding CN⁻ orbitals to the half-filled b₁(x²−y²) HOMO.     

Immunochemical studies of trehalose-containing major glycolipid from Tsukamurella pulmonis

The chemical structure of the major glycolipid present in the chloroform-methanol extract of bacterial biomass of Tsukamurella pulmonis is reported. This compound was purified by TLC and HPLC. The sugar analysis revealed only glucose. Detailed chemical analyses, NMR, and MALDI FT-ICR-mass spectrometric studies identified 2,3-di-O-acyl-α-d-glucopyranosyl-(1→1)-α-d-glucopyranose as the final structure. Short branched fatty acids (4:0 or 5:0) were linked to C-3 and saturated, mono, and diunsaturated 18:0, 18:1, 18:2, 20:1, 20:2, and 20:0 to C-2 of the same glucose residue. ELISA tests revealed the weak cross-reactivity of the glycolipid with rabbit antisera against cells of T. paurometabola, Rhodococcus wratislaviensis, and Nocardiopsis dassonvillei.     

Larsenia salina gen. nov., sp. nov., a new member of the family Halomonadaceae based on multilocus sequence analysis

Two Gram-staining-negative, moderately halophilic bacteria, strains M1-18^T and L1-16, were isolated from a saltern located in Huelva (Spain). They were motile, strictly aerobic rods, growing in the presence of 3–25% (w/v) NaCl (optimal growth at 7.5–10% [w/v] NaCl), between pH 4.0 and 9.0 (optimal at pH 6.0–7.0) and at temperatures between 15 and 40 °C (optimal at 37 °C). Phylogenetic analysis based on 16S rRNA gene sequence comparison showed that both strains showed the higher similarity values with Chromohalobacter israelensis ATCC 43985^T (95.2–94.8%) and Chromohalobacter salexigens DSM 3043^T (95.0–94.9%), and similarity values lower than 94.6% with other species of the genera Chromohalobacter, Kushneria, Cobetia or Halomonas. Multilocus sequence analysis (MLSA) based on the partial sequences of atpA, rpoD and secA housekeeping genes indicated that the new isolates formed an independent and monophyletic branch that was related to the peripheral genera of the family Halomonadaceae, Halotalea, Carnimonas and Zymobacter, supporting their placement as a new genus of the Halomonadaceae. The DNA–DNA hybridization between both strains was 82%, whereas the values between strain M1-18^T and the most closely related species of Chromohalobacter and Kushneria were equal or lower to 48%. The major cellular fatty acids were C_18:1ω7c/C_18:1ω6c, C_16:0, and C_16:1ω7c/C_16:1ω6c, a profile that differentiate this new taxon from species of the related genera. We propose the placement of both strains as a novel genus and species, within the family Halomonadaceae, with the name Larsenia salina gen. nov., sp. nov. The type strain is M1-18^T (= CCM 8464 = CECT 8192^T = IBRC-M 10767^T = LMG 27461^T).     

Reevaluation of the nutrient mineralization process by infaunal bivalves (Ruditapes philippinarum) in a shallow lagoon in Hokkaido, Japan

Previous estimations of nutrient mineralization in the water column by infaunal bivalves might have been overestimated because of underestimation of the uptake process by microphytobenthos in the field. We conducted field surveys of environmental conditions and quantitative sampling of Ruditapes philippinarum in a shallow lagoon system (Hichirippu Lagoon, eastern Hokkaido, Japan) in August 2006. We recorded the spatial distribution pattern and the molar ratio of dissolved inorganic nutrients to determine the limiting nutrients for microphytobenthos, to evaluate the input and output of nutrients at the entrance of the lagoon station, and to estimate potential nutrient mineralization by R. philippinarum. Our aim was to reevaluate the nutrient mineralization process by infaunal bivalve species. In this study, the mean standing stock of microphytobenthos inhabiting surface sediment (5 mm thick) on the tidal flats was 100 times higher than that of phytoplankton (1 m depth). Low N/P and high Si/N ratios (mean = 2.6 and 17.6, respectively) near the entrance of the lagoon compared to those of microphytobenthos (N:P:Si = 10.1:1:18) clearly suggest N deficiency. The flux of NH₄-N coming into the lagoon was 3.4 kmolN d^− 1, and the flux out was − 3.7 kmolN d^− 1. Thus, assuming that there would have been no phytoplankton and microphytobenthos uptake during the day, 0.3 kmolN d^− 1 of NH₄-N was produced within the lagoon. However, the NH₄-N mineralization rate of the clams has been estimated to be approximately 7.7 ± 6.8 kmolN d^− 1. Thus, 96% (7.4 kmolN d^− 1, i.e., 7.7 kmolN d^− 1 minus 0.3 kmolN d^− 1) of the NH₄-N mineralized by the clam was consumed by microphytobenthos. In contrast, if all the NH₄-N inflow (3.1 kmolN d^− 1) was consumed by the microalgae before outflow, 52% (4.0 kmolN d^− 1, i.e., 7.7 kmolN d^− 1 minus 3.7 kmolN d^− 1) of the NH₄-N mineralized by the clams should have been consumed by microphytobenthos. Microphytobenthos on the tidal flats (11.3 ± 11.8 kmolN) used all of the surplus nutrients (between 4.0 and 7.4 kmolN d^− 1), and the temporal division rate [=(NH₄-N uptake)/(standing stock of microphytobenthos)] of microphytobenthos would have to be between 0.35 and 0.65 d^− 1. Residual NH₄-N (0.3 - 3.7 kmolN d^− 1) was the water-column source and accounted for 12-148% of NH₄-N in the water column near the entrance of the lagoon (2.5 ± 1.4 kmolN) per day. This is the first field-based observation with a quantitative evaluation of nutrient mineralization by infaunal bivalves and nutrient uptake by microphytobenthos.     

Studies on monoacylglycerols from Gordona lentifragmenta,Gordona bronchialis and Gordona rubropertincta

Monoacylglycerols containing α-branched-β-hydroxylated fatty acids (mycolic acids) ranging from C₄₂ to C₅₀ and from C₆₀ to C₆₆, were isolated from Gordona lentifragmenta and from G. bronchialis, respectively. On the other hand, G. rubropertincta showed only a monoacylglycerol fraction which released non-hydroxylated fatty acids; they were identified as C_16:0-, C_16:1,- C_18:1- and branched C_19:0-fatty acids. This last component was identified as 10-methyl octadecanoic acid (tuberculostearic acid).     

Intestinal absorption of dietary maize glucosylceramide in lymphatic duct cannulated rats

Sphingolipids are ubiquitous in all eukaryotic organisms. Various physiological functions of dietary sphingolipids, such as preventing colon cancer and improving the skin barrier function, have been recently reported. One of the common sphingolipids used as a foodstuff is glucosylceramide from plant sources, which is composed of sphingoid bases distinct from those of mammals. However, the fate of dietary sphingolipids derived from plants is still not understood. In this study, we investigated the absorption of maize glucosylceramide in the rat intestine using a lipid absorption assay of lymph from the thoracic duct. The free and complex forms of trans-4,cis-8-sphingadienine, the predominant sphingoid base of maize glucosylceramide, were found in the lymph after administration of maize glucosylceramide. This plant type of sphingoid base was detected in the ceramide fraction and N-palmitoyl-4,8-sphingadienine (C16:0-d18:2) and N-tricosanoyl-4,8-sphingadienine (C23:0-d18:2) were identified by LC-MS/MS. The cumulative recovery of 4t,8c-sphingadienine in the lymph was very low. These results indicate that dietary glucosylceramide originating from higher plants is slightly absorbed in the intestine and is incorporated into ceramide structures in the intestinal cells. However, it appears that the intact form of sphingoid bases is not reutilized well in the tissues.     

Treatment of industrial wastewater with two-stage constructed wetlands planted with Typha latifolia and Phragmites australis

Industrial wastewater treatment comprises several processes to fulfill the discharge permits or to enable the reuse of wastewater. For tannery wastewater, constructed wetlands (CWs) may be an interesting treatment option. Two-stage series of horizontal subsurface flow CWs with Phragmites australis (UP series) and Typha latifolia (UT series) provided high removal of organics from tannery wastewater, up to 88% of biochemical oxygen demand (BOD₅) (from an inlet of 420 to 1000 mg L⁻¹) and 92% of chemical oxygen demand (COD) (from an inlet of 808 to 2449 mg L⁻¹), and of other contaminants, such as nitrogen, operating at hydraulic retention times of 2, 5 and 7 days. No significant (P < 0.05) differences in performance were found between both the series. Overall mass removals of up to 1294 kg COD ha⁻¹ d⁻¹ and 529 kg BOD₅ ha⁻¹ d⁻¹ were achieved for a loading ranging from 242 to 1925 kg COD ha⁻¹ d⁻¹ and from 126 to 900 kg BOD₅ ha⁻¹ d⁻¹. Plants were resilient to the conditions imposed, however P. australis exceeded T. latifolia in terms of propagation.