Luffolide,a novel anti-inflammatory terpene from the spongeLuffariella sp.

Summary Luffolide (4) is a minor metabolite of the spongeLuffariella sp. from Palau. The structure of luffolide was determined by single crystal X-ray analysis. Luffolide is relatively unstable and undergoes a complex cyclization reaction to give the hexacyclic products5 and6. Luffolide (4) has some of the anti-inflammatory properties of manoalide (1): this may help to define the chemical reaction between manoalide (1) and phospholipase A₂.All crystallographic calculations were done on a PRIME 9950 computer operated by the Cornell Chemistry Computing Facility. Principal programs employed were: FOBS, a data reduction program by G.D. Van Duyne, Cornell University, 1987; MULTAN 80, and RANTAN 80, systems of computer programs for the automatic solution of crystal structures from X-ray diffraction data (locally modified to perform all Fourier calculations including Patterson syntheses) written by P. Main, S. E. Hull, L. Lessinger, G. Germain, J. P. Declercq and M. M. Woolfson, University of York, England, 1980 BDLS, an, anisotropic block diagonal least squares refinement written by K. Hirotsu, E. Arnold, and G. D. Van Duyne, Cornell University, 1987; PLUTO 78, a locally modified crystallographic illustration program by W. D. S. Motherwell, Cambridge Crystallographic Data Centre, 1978; and BOND, a program to calculate molecular parameters and prepare tables written by K. Hirotsu and G. Van Duyne, Cornell University, 1985.Acknowledgment. We thank the Government of the Republic of Palau for a scientific research permit. We thank Dr Klaus Rützler, Smithsonian Institution, Washington, D.C. for identifying the sponge and Mary Kay Harper for performing additional bioassays. This research was supported by grants from the Sea Grant College Programs of California [Projects R/MP-30 to DJF) and R/MP-31 (to RSJ)] and New York (to JC) and the National Institutes of Health (CA 24487 to JC).     

Differences in chromosome A arrangement betweenDrosophila madeirensis andDrosophila subobscura

Summary The proximal half of the A (=X) chromosome ofD. madeirensis has a gene arrangement very similar to the A1 or A6 inversions found inD. subobscura. Polytene chromosome analysis of hybrids betweenD. madeirensis and strains ofD. subobscura homozygous for such inversions shows, however thatD. madeirensis has a gene arrangement different from any known forD. subobscura. These results provide evidence for a greater differentiation of the X chromosome in these species than has previously been described; it seems that the X chromosome is the only one that has undergone structural variation during the speciation process.     

In vitro metabolism of the trichothecene 4-monoacetoxyscirpenol by fungus- and non-fungus-feeding insects

Summary The metabolism of the trichothecene 4-monoacetoxyscirpenol by intact gut tissue was determined in the fungus-feeding Nitidulid,Carpophilus hemipterus (L.) and the non-fungus-feeding caterpillars, the fall armyworm,Spodoptera frugiperda (J. E. Smith) and the corn earworm,Heliothis zea (Boddie). The primary metabolite was the hydrolysis product scirpentriol. The amount of metabolism by theC. hemipterus larvae was ca 10 times that of the caterpillars on a per mg protein basis, suggesting metabolic adaptation for feeding on fungi that may contain mycotoxins.Acknowledgment. The authors wish to thank S. Taylor for technical assistance.The mention of firm names or trade products does not imply that they are endorsed or recommended by the U.S. Department of Agriculture over other firms or similar products not mentioned.     

Observations on the toxicity and metabolic relationships of polygodial,the chemical defense of the nudibranchDendrodoris limbata

Summary Polygodial (1), the defense metabolite stored in the skin of the nudibranchDendrodoris limbata, is toxic for the mollusc itself when injected into the hepatopancreas. Biosynthetic experiments using labeled mevalonic acid were devised to investigate a possible metabolic relationship between1 and the mixture of sesquiterpenoidic esters2, stored in the hepatopancreas. The results suggest that1 and2 are biosynthesized by independent pathways.Thanks are due to G. Villani for supplyingDendrodoris limbata and to A. Trabucco for technical assistance.     

Comparative study of oxalate oxidase in three genotypes ofSorghum vulgare

Summary The presence of an oxalate oxidase (EC 1.2.3.4) has been demonstrated in 15,000×g supernatants prepared from 10-day-old seedlings of three genotypes ofSorghum vulgare: grain sorghum hybrid (CSH-5), grain-cum-forage sorghum (PC-6) and forage sorghum (PC-1). The specific activity of the enzyme in the different tissues of seedlings was found to be present in the order leaves > stems > roots in PC-6 and PC-1, but this order was reversed in CSH-5. A comparison of the different properties of the leaf enzyme of these three genotypes of sorghum revealed that the enzyme has maximum activity in the acidic pH range from 4.0 to 5.0 and in the temperature range from 37°C to 40°C. The enzyme was stimulated by Cu²⁺ and Fe²⁺. The rate of H₂O₂ formation in the enzyme reaction was linear up to 5 min and was stoichiometrically related to oxalate consumption. The enzyme is unaffected by Na⁺ at physiological concentration (0.15 M). The superiority of this enzyme over moss and other plant enzymes for enzymic determination of urinary oxalate is discussed.     

Polyclinal,a new sulfated polyhydroxy benzaldehyde from the marine ascidianPolyclinum planum

Summary A new sulfated polyhydroxy benzaldehyde has been isolated from extracts of the temperate colonial ascidianPolyclinum planum. The structure of the new metabolite was solved by an X-ray crystallographic study. The highest concentration of this metabolite was found in the zooid-rich outer layers of this ascidian suggesting that it may represent a potential chemical defense against predators.     

The evolutionary history ofDrosophila buzzatii. V. Differential survivorship onOpuntia betweenD. buzzatii andD. serido

Summary Survival time ofDrosophila buzzatii adults on anOpuntia (prickly pear) medium was significantly longer than that of its nearest relativeD. serido. A significant difference was also found betweenD. buzzatii adults from two experimental populations, one of them fed onOpuntia rots for more than two years and another one kept on standardDrosophila medium for the same period of time. These results suggest that adult selection may be taking place in cactiphilicDrosophila in their natural habitats and could be responsible for the niche differentiation betweenD. buzzatii andD. serido.This work has been supported by the Comisión Asesora de investigación Científica y Técnica, Spain, by funds to project 4514/79 awarded to the third author.     

High affinity recognition of a <Emphasis Type="Italic">Phytophthora</Emphasis> protein by <Emphasis Type="Italic">Arabidopsis</Emphasis> via an RGD motif

The RGD tripeptide sequence, a cell adhesion motif present in several extracellular matrix proteins of mammalians, is involved in numerous plant processes. In plant-pathogen interactions, the RGD motif is believed to reduce plant defence responses by disrupting adhesions between the cell wall and plasma membrane. Photoaffinity cross-linking of [¹²⁵I]-azido-RGD heptapeptide in the presence of purified plasma membrane vesicles of Arabidopsis thaliana led to label incorporation into a single protein with an apparent molecular mass of 80 kDa. Incorporation could be prevented by excess RGD peptides, but also by the IPI-O protein, an RGD-containing protein secreted by the oomycete plant pathogen Phytophthora infestans. Hydrophobic cluster analysis revealed that the RGD motif of IPI-O (positions 53–56) is readily accessible for interactions. Single amino acid mutations in the RGD motif in IPI-O (of Asp⁵⁶ into Glu or Ala) resulted in the loss of protection of the 80-kDa protein from labelling. Thus, the interaction between the two proteins is mediated through RGD recognition and the 80-kDa RGD-binding protein has the characteristics of a receptor for IPI-O. The IPI-O protein also disrupted cell wall-plasma membrane adhesions in plasmolysed A. thaliana cells, whereas IPI-O proteins mutated in the RGD motif (D56A and D56E) did not.Received 23 October 2003; received after revision 5 December 2003; accepted 12 December 2003     

Transfer of secondary metabolites from the spongesDysidea fragilis andPleraplysilla spinifera to the mantle dermal formations (MDFs) of the mudibranchHypserlodoris webbi

The opisthobranch molluscHypselodoris webbi is able to select, among its potential preys, sponges chemically rich in furanosesquiterpenoids. The sequestered secondary metabolites act as defensive allomones against predators and are accumulated in some dorsal glands (MDFs). This transfer from sponges to MDFs has been proven by maintainingH. webbi together with some selected sponges in an aquarium for a prolonged period.     

Antimalarial drugs: recent advances in molecular determinants of resistance and their clinical significance

Molecular determinants of antimalarial drug resistance are useful and informative tools that complement phenotypic assays for drug resistance. They also guide the design of strategies to circumvent such resistance once it has reached levels of clinical significance. Established resistance to arylaminoalcohols such as mefloquine and lumefantrine in SE Asia is mediated primarily by gene amplification of the P. falciparum drug transporter, pfmdr1. Single nucleotide polymorphisms in pfmdr1, whether assessed in field isolates or transfection experiments, are associated with changes in IC₅₀ values (to arylaminoalcohols and chloroquine), but not of such magnitude as to influence clinical treatment outcomes. Recently described emerging in vitro resistance to artemisinins in certain areas correlates with mutations in the SERCA-like sequence PfATP6 and supports PfATP6 as a key target for artemisinins. Received 13 February 2006; revised after revision 7 March 2006; accepted 29 March 2006     

Selected decrease of haemocytes of the freshwater snailPlanorbarius corneus (L.) (Gastropoda,Pulmonata) after bacteria injection

Summary The decrease of haemolymph phagocytic cells (SH) inPlanorbarius corneus after bacterial injection seems to be mediated by humoral factor(s) released into the haemolymph. SH show different adhesiveness in vitro in the presence of bacterial metabolic products.     

Isolation of indole-3-acetic acid methyl ester,a metabolite of indole-3-acetic acid fromPseudomonas amygdali

From the culture filtrates ofPseudomonas amygdali the methyl ester of indole-3-acetic acid (IAA), a product of indole-3-acetic acid metabolism which has the same auxin activity as the free acid, has been isolated. This is the first report of its occurrence as a microbial metabolite.     

Identification of mucondialdehyde as a novel stress metabolite

In a survey of antifungal stress compounds induced by cupric chloride we found that leaves ofChenopodium album exuded a highly fungitoxic metabolite mucondialdehyde (trans-2,trans-4-hexadienedial), which was associated with 13-oxo-9,11-tridecadienoic acids (cis-9,trans-11 andtrans-9,trans-11 isomers) presumably resulting from -scission of 13-hydroperoxy-octadecadi(tri)enoic acid. The biogenesis and role as a general defensive agent in plants are briefly discussed.     

Intrapopulational genetic variation in the hybridization betweenDrosophila melanogaster females andD. simulans males

Summary Intrapopulational variation on interspecific crossing ability betweenD. melanogaster andD. simulans has been measured. When themelanogaster females andsimulans males were crossed, hybridization ranged from 3 to 34%, the female component of variation being more important than the male component. This point is discussed in relation with the role played by each sex in sexual isolation.     

Characterization of victorin C,the major host-selective toxin fromCochliobolus victoriae: Structure of degradation products

Summary Several host-selective toxins have been isolated in pure form culture filtrates ofCochliobolus victoriae. Acid hydrolysis of the major toxin, victorin C (apparent mol.wt 796), produced five fragments to which structures1–5 have been assigned. Spectroscopic techniques revealed that the toxin contains an additional subunit corresponding to6; thus all the components of victroin C are accounted for.     

Furan fatty acid steryl esters from the marine spongeDictyonella incisa which show inflammatory activity

Summary Three new furan fatty acids, (9Z, 19Z)-3, 6-epoxyhexacosa-3,5,19-tetraenoic acid (1a), (8Z, 11Z, 14Z, 17Z)-3, 6-epoxyeicosa-3,5,8,11,14,17-hexaenoic acid (2a), and (8Z, 11Z, 14Z, 17E)-3, 6-epoxyeicosa-3,5,8,11,14,17-hexaenoic acid (3a), and a new polyunsaturated fatty acid (5Z, 8Z, 11Z, 14Z, 17E)-eicosa-5,8,11,14,17-pentaenoic acid (6a), present in the spongeDictyonella incisa as the respective steryl esters, have been isolated as methyl esters and their structures have been determined by spectral and chemical analysis. The furan fatty acid esters have shown a high inflammatory activity, which suggests their potential role as feeding deterrents.     

Insect tissues,not microorganisms,produce linoleic acid in the house cricket and the American cockroach

Summary Biosynthesis of linoleic acid, 182(n–6), was unambiguously demonstrated to occur in the cockroach,Periplaneta americana, and the cricket,Acheta domesticus. Axenic tissue from both of these insect species was demonstrated by radio-gas-liquid chromatography (radio-GLC) and radio-high-performance liquid chromatography (radio-HPLC) to incorporate [1-¹⁴C]acetate and [1-¹⁴C]oleate into this essential fatty acid.This work was supported by the National Science Foundation under grant DCB-8914417. We would like to thank Coby Schal for his generous gift of American cockroaches and Tania Kellermeyer for her excellent technical assistance.     

Ethanol metabolizing system inDrosophila melanogaster: subcellular distribution of some main enzymes

Summary The subcellular distribution of some enzymes which play a part in ethanol metabolism have been determined by differential centrifugation of homogenates of adultD. melanogaster flies of various genotypes. Aldehyde dehydrogenase, recently discovered inD. melanogaster, is present in the five genotypes studied. It has been found however to be, in vitro at least, most active in a strain lacking both alcohol dehydrogenase and aldehyde oxidase.     

A potent actomyosin ATPase activator from the Okinawan marine spongeAgelas cf.nemoechinata

Summary A bromine-containing alkaloid, oxysceptrin, has been isolated as a potent actomyosin ATPase activator from the Okinawan marine spongeAgelas cf.nemoechinata, and the structure elucidated to be1 on the basis of the 2D NMR spectral data.Acknowledgments. We thank Mr Z. Nagahama for his help in sponge collecting and Ms M. Takamatsu for her technical assistance.