Chemical structure of the ether lipids of thermophilic acidophilic bacteria of the Caldariella group

The lipids of the Caldariella group of extremely thermophilic acidophilic bacteria are based on a 72-membered macrocyclic tetraether made up from two C₄₀ diol units and either two glycerol units or one glycerol and one nonitol. The C₄₀ components have the 16,16′-biphytanyl skeleton and the detailed structure of three of them is established.     

Ketonic rancidity in coconut due to xerophilic fungi

A type of deterioration called ketonic rancidity occurred in coconut after inoculation with four xerophilic fungi, Eurotium amstelodami, E. chevalieri, E. herbariorum and Penicillium citrinum. The fungi were incubated at low water activity and oxygen tension. A homologous series of aliphatic methyl ketones and secondary alcohols C₅C₁₁ were isolated and identified in the rancid samples after fungal growth. Evidence is presented that odd numbered methyl ketones (C₅C₁₁) are derived from even numbered short chain fatty acids with one more carbon atoms than the ketones via a modified β-oxidation of the parent fatty acid. Heptan-2-one and heptan-2-ol are the main reaction products except in the case of E. herbariorum where even numbered hexan-2-one, hexan-2-ol, octan-2-one and octan-2-ol were produced. Other moulds grown on coconut under similar conditions—Aspergillus flavus Link and Chrysosporium farinicola (Burnside) Skou (C. fastidium Pitt)—did not cause ketonic deterioration.     

m-Terphenylphosphines: Synthesis, structures and coordination properties

A series of m-terphenylphosphines TerphPCl₂, TerphPH₂ and TerphPMe₂ (Terph = 2,6-Mes₂C₆H₃-, 2,6-(4-t-BuC₆H₄)₂C₆H₃-, 2,6-(3,5-Me₂C₆H₃)₂C₆H₃-, 2,6-(2,6-Et₂C₆H₃)₂C₆H₃-, and 2,6-(2,6-i-Pr₂C₆H₃)₂C₆H₃-; Mes = 2,4,6-Me₃C₆H₂-) was prepared and fully characterized. The structural investigation by X-ray crystallography and density functional theory revealed significant distortions in the environment of the ipso carbon and phosphorus centers. These can be traced back to steric interactions and repulsions of the chlorine and methyl substituents on phosphorus with one of the flanking arenes of the m-terphenyl substituents. The primary phosphine 2,6-Mes₂C₆H₃PH₂, 6, and the dimethylphosphine 2,6-(3,5-Me₂C₆H₃)₂C₆H₃PMe₂, 9, readily form complexes with the Cl₂Ru(p-cymene) complex fragment, whereas the larger phosphine 2,6-Mes₂C₆H₃PMe₂, 8, does not. Heating of the complexes TerphPR₂Ru(Cl₂)(p-cymene) 11 and 12 and the mixture of 8 and {(p-cymene)RuCl₂}₂ lead to expulsion of the p-cymene ligand and intramolecular η⁶ coordination of one of the flanking arene rings to the ruthenium center to afford the complexes Cl₂RuP(H₂)C₆H₃-2-η⁶-Mes-6-Mes, 13, Cl₂RuP(Me₂)C₆H₃-2-η⁶-Mes-6-Mes, 14, and Cl₂RuP(H₂)C₆H₃-2-η⁶-(3,5-Me₂C₆H₃)-6-(3,5-Me₂C₆H₃), 15. All complexes were characterized by NMR spectroscopy and complexes 14 and 15 also by X-ray crystallography.     

Hydrocarbons,phenols and sterols of the testa and pigment strand in the grain of Hordeum distichon

Material from the testa of decorticated barley grains contained hydrocarbons, esters, triglycerides, free sterols, 5-n-alkylresorcinols, and traces of free alcohols, carbonyl compounds, and various polar, acidic materials. The hydrocarbon fraction was mainly a series of n-alkanes, extending at least from C₁₁ to C₃₆, in which the C₂₉ and C₃₁ components were prominent. Two minor series of alkanes were also present. Sometimes a trace of an unsaturated hydrocarbon was detected. The ester fraction contained sterols and alkanols esterified by fatty acids, which differed in relative amounts from the fatty acids found in the triglycerides. The triglycerides were thought to have leached from within the grain. At least five free sterols were present, including sitosterol and campesterol. The 5-n-alkylresorcinols were at least twelve members of a homologous series, of which four, C₂₅, C₂₇, C₂₉, and C₃₁, made 98% of the total. Members of the series with even numbers of carbon atoms were also present. It is suggested that they are partly responsible for excluding microorganisms from the interior of the grain. The testa membrane, with the associated pigment strand, contained an estolide of fatty acids and various hydroxyacids, a polysaccharide component, and uncharacterized material.     

Incorporation of labelled glycerols into ether lipids in Caldariella acidophila

The lipids of Caldariella acidophila, an extreme thermophile member of the new archaebacteria group, are macrocyclic tetraethers. They are made up of two glycerol molecules (or one glycerol and one nonitol) bridged through ether linkages by two C₄₀16,16′-biphytanyl chains. To elucidate the biosynthesis of the glycerol moiety of these tetraethers and the mechanism of glycerol ether assembly, labelled [U-¹⁴C, 1(3)-³H]glycerol and [U-¹⁴C, 2-³H]glycerol, were fed to C. acidophila. Both precursors were selectively incorporated with high efficiency, and without any change in the ³H/¹⁴C ratio, in the glycerol moiety of tetraethers. These results suggest that the ether forming step in the biosynthesis of tetraether lipids of C. acidophila, occurs without any loss of hydrogen from any of the glycerol carbons which in turn could be directly alkylated by geranylgeranyl pyrophosphate. The incorporation of radioactivity in the isoprenoid chains and into nonitol is also analysed.     

Venom and Dufour's gland secretions in an Australian species of Camponotus

Constituents of the venom (1) and Dufour's gland (25) have been characterized in an Australian representative of the highly evolved ant subfamily Formicinae. The venom reservoir of this ant, Camponotus intrepidus, contains formic acid, identified as the benzyl ester. The Dufour's gland contains a major hydrocarbon and a minor fatty acid fraction. Hydrocarbons include the normal alkanes, C₁₀ to C₁₇ (82 per cent); two series of monomethylalkanes, C₁₂, C₁₃, C₁₄, C₁₆, and C₁₇, the 3-methyl derivatives comprise approximately 16 per cent, and the 5-methylalkanes 2 per cent of the total; there are trace proportions of the n-alkenes, C₁₂, C₁₃, and C₁₅. The minor fatty acids, myristic, pentadecanoic, palmitic, and stearic are present in the ratio 2 : 2 : 12 : 11.     

A range of ether core lipids from the methanogenic archaebacterium Methanosarcina barkeri

The core ether lipids of the methanogenic archaebacterium Methanosarcina barkeri were found to consist of C₂₀,C₂₀ glycerol diether and trace amounts of C₂₀,C₂₅ glycerol diether, C₂₀ glycerol monoether, C₄₀,C₄₀ diglycerol tetraethers with 1–3 cyclopentane rings, and a novel C₂₀,C₂₀ tetritol diether.     

Synthesis, characterization and structure of some arylantimony ferrocenylacrylates

A series of arylantimony ferrocenylacrylates with the formula (C₅H₅FeC₅H₄CHCHCO₂)_nSbAr_(5−n) (n=1, 2; Ar C₆H₅, 4-CH₃C₆H₄, 3-CH₃C₆H₄, 2-CH₃C₆H₄, 4-FC₆H₄) have been synthesized and characterized by elemental analysis, IR, ¹H NMR and mass spectra. The crystal structures of C₅H₅FeC₅H₄CHCHCO₂Sb(C₆H₅)₄ (I₁) and (C₅H₅FeC₅H₄CHCHCO₂)₂Sb(C₆H₅)₃ (II₁) have been determined by X-ray diffraction.     

Synthesis,insecticidal activities and SAR of novel phthalamides targeting calcium channel

In order to find novel and environmental friendly insecticides targeting the ryanodine receptor, three series of novel phthalamides containing heptafluoroisopropyl group, low fluorine atoms group and non-fluorine group were designed and synthesized. 35 novel structures of three series were obtained. Insecticidal activities of title compounds against oriental armyworm (Mythimna separata) and diamondback moth (Plutella xylostella) indicated that most of title compounds showed moderate to high activities at the tested concentration. The structure–activity relationship (SAR) was discussed in detail. During synthesizing title compounds B₈, C₇, D₁, D₉ and D₁₂, their corresponding positional isomers (B₈′, C₇′, D₁′, D₉′ and D₁₂′) were afforded, and their structures were confirmed by 2D NMR. The calcium-imaging technique was also applied to investigate the effects of compounds B₂, B₁₀, C₄ and C₅ on the intracellular calcium ion concentration ([Ca²⁺]_i), which indicated that they released stored calcium ions from endoplasmic reticulum, which denoted that some compounds are potential modulators of the insect ryanodine receptor (RyR).     

Qualitative and Quantitative Analyses of Gibberellins in Vegetative Shoots of Normal, dwarf-1, dwarf-2, dwarf-3, and dwarf-5 Seedlings of Zea mays L

Gibberellins A₁₂ (GA₁₂), GA₅₃, GA₄₄, GA₁₉, GA₁₇, GA₂₀, GA₂₉, GA₁, and GA₈ have been identified from extracts of vegetative shoots of normal (wild type) maize using full scan capillary gas chromatography-mass spectrometry and Kovats retention indices. Seven of these gibberellins (GAs) have been quantified by capillary gas chromatography-selected ion monitoring using internal standards of [¹⁴C₄]GA₅₃, [¹⁴C₄]GA₄₄, [²H₂] GA₁₉, [¹³C₁]GA₂₀, [¹³C₁]GA₂₉, [¹³C₁]GA₁, and [¹³C₁]GA₈. Quantitative data from extracts of normal, dwarf-1, dwarf-2, dwarf-3, and dwarf-5 seedlings support the operation of the early 13-hydroxylation pathway in vegetative shoots of Zea mays. These data support the positions in the pathway blocked by the mutants, previously assigned by bioassay data and metabolic studies. The GA levels in dwarf-2, dwarf-3, and dwarf-5 were equal to, or less than, 2.0 nanograms per 100 grams fresh weight, showing that these mutants are blocked for steps early in the pathway. In dwarf-1, the level of GA₁ was very low (0.23 nanograms per 100 grams fresh weight) and less than 2% of that in normal shoots, while GA₂₀ and GA₂₉ accumulated to levels over 10 times those in normals; these results confirm that the dwarf-1 mutant blocks the conversion of GA₂₀ to GA₁. Since the level of GAs beyond the blocked step for each mutant is greater than zero, each mutated gene probably codes for an altered gene product, thus leading to impaired enzyme activities.     

Hydrocarbons,sterols and tocopherols in the seeds of six Adansonia species

The composition of the unsaponifiable matter of the lipids of six Adansonia species (A. grandidieri, A. za, A. fony, A. madagascariensis, A. digitata and A. suarezensis) was investigated. The total unsaponifiable content, its general composition and the identity of the components of the hydrocarbon, sterol and tocopherol fractions are presented. The unsaponifiable content in oil ranges from 0.4 to 1.1% (hexane method) and from 0.6 to 2.2% (diethyl ether method). In two species (A. grandidieri and A. suarezensis) the major components are 4-demethylsterols (23–42%) tocopherols (37-10%) and hydrocarbons (15–17%). In both species examined, eight 4-demethylsterols occur in the sterol fraction with sitosterol (81–88%) being predominant. Among the four tocopherols present, γ-tocopherol (68–98%) is the major compound. Each Adansonia species shows a characteristic gas liquid chromatography pattern for the hydrocarbon fraction. Squalene is the major component for five species (40–75%). Iso-, anteiso- and other branched hydrocarbons were not identified but were present in small amounts in comparison with n-alkanes. The dominance of odd- over even-carbon number chain length of n-alkanes was not observed in any species. The results show that C₂₂, C₂₅, C₂₆, C₂₇, C₂₈ and C₂₉ are the most frequent major constituents.     

Specific features of photorespiration in photosynthetically active organs of C3 plants

Photorespiration of photosynthetically active organs of C₃ plants (leaf, ear, stem, and leaf sheath) and C₄ plants (leaf, tassel, stem, leaf sheath, ear husk) grown under greenhouse and field conditions was studied. Photorespiration was measured using a PTM-48A high-technology monitor of photosynthesis (Bioinstruments S.R.L., Moldova). It is shown that photorespiration (CO₂ ejection after light turning off — apparent photorespiration) in C₃ plants is characteristic only for their leaves. In other photosynthesizing organs, photorespiration was absent, like in the photosynthesizing organs of C₄ plants. The absence of such after-light CO₂ outburst was observed for 31 genotypes: 18 cereal species belonging to four species (Triticum aestivum L., T. durum Desf., Secale cereale L., and Triticale); 6 grain legumes belonging to 2 species (Pisum sativum L. and Glycine max L.); 7 species of wild and rarely cultivated genotypes (T. boeoticum Boiss., T. dicoccoides Koern., T. dicoccum Schuebl., T. spelta L., T. compactum Host., T. monococcum L., and T. sphaerococcum Persiv.), and 2 genotypes of C₄ plants (Zea mays L. and Sorgum vulgaris L.). In all tested photosynthetically active genotypes, except of the C₃ plant leaves, apparent photorespiration was absent, but rather active glycolate cycle operated. The activity of this cycle was determined from the activity of the key enzyme of this cycle — glycolate oxidase. It was supposed that C₃ plants have two mechanisms of CO₂ assimilation: the first one — the mechanism of C₃ type localized in the leaves and the second one localized in other photosynthesizing organs, similar or with some elements of C₄ mechanism of CO₂ assimilation, limiting after-light CO₂ ejection during the metabolism of glycolate.     

Remains of a Pliocene Mammut borsoni (Hays, 1834) (Proboscidea,Mammalia), from Milia (Grevena,W. Macedonia,Greece)

A partial skeleton of the mastodont Mammut borsoni (Hays, 1834) (Proboscidea), was excavated from Pliocene deposits at Milia — Grevena, W. Macedonia, in 1996–1999. The skeleton includes substantial portions of the skull — maxillary area — with left and right molar series (M² + M³); with the longest upper tusks ever found in Greece (4.39 m); the most complete mandible with left and right molar series (M₂ + M₃) and two lower incisor tusks, as well as post-cranial skeleton. It represents a very large adult of about 40 years in age. The high age of the finding is partly corroborated by ESR dating studies of tooth enamel, indicating an age probably beyond the upper dating range of this technique (approx. 800 000 years). The evolutionary position of this specimen among mammutids is also discussed.     

Haptotropic shifts in mononuclear complexes of substituted pentalenes: A DFT investigation of the [CpFe(C8H4R2)] (R = H, Me, NH2, CF3, CN ; q = −1, 0, +1) series

The haptotropic migration of Fe from the unsubstituted ring to the substituted one in the pentalenic complexes [CpFe(η⁵-1,3 C₈H₄R₂)]^q (q = +1, 0, −1) has been investigated by the means of DFT calculations in the case of R = H, CH₃, NH₂, CF₃ and CN. The low energy pathway is a least-motion one-step process in the cationic case. In the anionic series, it is a two-step process involving an intermediate in which the metal moiety is η³-bonded in an exocyclic way to the pentalene ligand. The activation barriers and the preference for the Fe coordination on one ring rather on the other one is investigated with respect to the donor or acceptor abilities of R. The effect of changing q on the haptotropic situation is analyzed in terms of redox molecular switching.     

Separation and Identification of Fatty Acids

An improved method is described for separating saturated fatty acids by reversed-phase paper chromatography. The 2,4-dinitrophenylhydrazides prepared from saturated fatty acids from C₂ to C₂₂ are run upward on paper impregnated with tetralin, using 90% methanol—acetic acid—tetralin, 80% ethanol—acetic acid—tetralin, or 90% methanol—tetralin as the moving solvent. The simultaneous separations of all even-carbon acids from C₆ to C₂₂, all odd-carbon acids from C₇ to C₁₉, and also all odd- and even-carbon acids from C₇ to C₁₉ can be successfully performed by means of this paper chromatography. The method is useful for the detection of component saturated fatty acids in natural fats.     

Comparative growth analyses of panicum species with differing rates of photorespiration

Panicum milioides, a naturally occurring species with reduced photorespiration, P. bisulcatum, a C₃ species, and P. miliaceum, a C₄ species, were grown for 4 weeks at altered pO₂ and pCO₂ and several vegetative growth parameters were determined at weekly intervals. Compared to a pO₂ of 10%, a greater O₂ inhibition of the relative growth rate and dry matter production was observed for P. bisulcatum than for P. milioides at both 21% and 40% O₂, whereas little effect of O₂ was noted for P. miliaceum. Similarly, exposures to elevated pCO₂ of 500 and 1000 μ1 CO₂/liter resulted in a greater stimulation of vegetative growth for P. bisulcatum than for P. milioides, with little effect on P. miliaceum. The CO₂ compensation concentration of P. milioides was less than that of P. bisulcatum over a pO₂ range of 5 to 40%. At 5% O₂, the compensation concentration was relatively O₂-insensitive, whereas above 5% it increased with increasing pO₂. It is concluded that P. milioides represents the first well documented example of a C₃ plant with reduced photorespiration, based on both leaf CO₂ exchange parameters and growth analyses of dry matter production.     

Ribonuclease activities in bean roots

Vicia faba meristematic and elongating root cells (zones 0–4 and 10–20 mm) contained one nuclease (A₁) and four ribonucleases (A₂, A₃, C₁, C₂). When the overall activity of each enzyme was expressed per cell, the elongating cells contained 4-, 4-, 4-, 10- and 17-fold more activity than meristematic cells for A₁, C₁, C₂, A₂ and A₃, respectively.     

The determination of polar lipid solubilization boundaries in dilute solutions by light scattering

An apparatus and procedure have been developed which facilitate the acquisition of particle free water by recirculation through a fine membrane filter in a closed system. The system also permits one to vary, independently, composition of two solutes over a few hundred mg/l range, with ± 1 mg/l accuracy, while monitoring scattering intensities.Using these techniques it has been possible to define the phase boundary governing the solubilization of distearoylphosphatidyl choline (DSPC), above its chain melting temperature, by three homologous (C₁₆, C₁₈, C₂₀) ammoniohexanoate (AH) surfactants. The data suggest that negligible (< 1 mg/l) solubilization occurs up to an onset concentration of surfactant, C_on, which for C₁₆AH is 0.77 of the cmc. Beyond C_on finite solubilization occurs with an appreciable efficiency, which peaks at C₁₈AH at 1.35 g/g.     

Acetate esters of saturated and unsaturated alcohols (C12–C20) are major components in Dufour glands of Bracon cephi and Bracon lissogaster (Hymenoptera: Braconidae), parasitoids of the wheat stem sawfly,Cephus cinctus (Hymenoptera: Cephidae)

Chemistry of Dufour glands associated with the venom complex in Bracon cephi (Gahan) and Bracon lissogaster Muesebeck (Hymenoptera; Braconidae), two parasitoids of the wheat stem sawfly, Cephus cinctus Norton (Hymenoptera: Cephidae), was examined by solid phase micro-extraction (SPME) and gas chromatography/mass spectrometry. Homologous series of five chemical classes were detected in individual glands from each species. Major classes included: (1) acetate esters of saturated and unsaturated primary alcohols with parent chain lengths from C₁₂ to C₂₀. Hexadecanyl acetate, octadecanyl acetate, and octadecenyl acetate were major components in B. cephi. The composition of the acetate series in B. lissogaster was similar except that the octadecanyl acetate was only a minor component. (2) A homologous series of monoenes from C_23:1 to C_35:1 were detected in both species, with C_29:1, C_31:1 and C_33:1 being the major components. Dienes from C_31:2 to C_35:2 and trienes (C_33:3–C_35:3) were also detected in both species. (3) A homologous series of n-alkanes from C₁₉ to C₃₁ was detected in both species. n-Tricosane was the major component. Minor components in both species included homologous series of both mono- and dimethyl branched alkanes. The Dufour gland hydrocarbon components in both B. cephi and B. lissogaster have some similarities to the composition of cuticular hydrocarbons of their host C. cinctus, a species with a complex pheromonal signaling system.     

Quantifying the electronic cis effect of phosphine, arsine and stibine ligands by use of rhodium(I) Vaska-type complexes

The cis effects of phosphine, arsine and stibine ligands have been evaluated by measuring the IR stretching frequency in dichloromethane of the carbonyl ligand in a series of Rh(I) Vaska-type complexes, trans-[RhCl(CO)(L)₂]. These data were correlated with those obtained by Tolman for the electronic trans influences in the [Ni(L)(CO)₃] complexes. The electronic contribution, χ_Fc, of ferrocenyl was determined as 0.8 from these plots by evaluating PPh₂Fc as ligand. In order to accommodate arsine and stibine ligands an additional correction term, to compensate for differences in the donor atom, was added to Tolman’s equation for calculation of the Tolman electronic parameter of phosphine ligands. In the resulting equation: ν(CO_Ni)=2056.1+∑_i=1³χ_i+C_L values for C_L of C_P=0, C_As=−1.5 and C_Sb=−3.1 are suggested for phosphine, arsine and stibine ligands, respectively. The crystal and molecular structures of trans-[RhCl(CO)(PPh₂Fc)₂] · 2C₆H₆, trans-[RhCl(CO){P(NMe₂)₃}₂] and trans-[RhCl(CO)(AsPh₃)₂] are reported. The Tolman cone angles for PPh₂Fc and P(NMe₂)₃ were determined as 169° and 166°, while the effective cone angles for PPh₂Fc, P(NMe₂)₃ and AsPh₃ were determined as 171°, 168° and 147°, respectively.