A comparative study of the fatty acid profile of Artemia franciscana and A. persimilis cultured at mesocosm scale

The goal of this study was to examine the fatty acid (FA) profile of two Artemia species, A. persimilis (Argentina) and A. franciscana (Great Salt Lake,Utah; USA) in coexistence at mesocosm scale. The experiment was carried out to 1) evaluate putative differences in the fatty acid composition of both species while they share resources and 2) to investigate the causes of such differences. Although the coexistence of these species in nature has not yet been observed, it remains possible that this situation may arise in the future mainly due to the invasive ability of A. franciscana. FA analyses were performed on individuals as well as on pooled biomasses of each species, and integrated in multivariate principal components analysis (PCA). Comparison of the relative abundance of FA between the two species revealed that interspecific differences in FA composition are greater than intraspecific variability. Higher percentages of unsaturation were found in the fatty acids of A. persimilis compared to A. franciscana, demonstrating that aside from a high phenotypic effect of diet on the FA composition of the animals, a species-specific genotypic effect should not be discarded.     

Methoxylated fatty acids in Blumeria graminis conidia

The total fatty acids (FA) composition of Blumeria graminis f.sp. tritici conidia, the causal agent of wheat powdery mildew, was analyzed as a function of their age. A total of 19 FA (C12-C24 saturated and unsaturated) and unusual methoxylated fatty acids (mFA) were detected in young, intermediate and old conidia. Two very long chain methoxylated FA were identified by GC-MS as 3-methoxydocosanoic and 3-methoxytetracosanoic acids. Medium chain FA were predominant in young conidia (75%, including 13% of mFA) while very long chain fatty acids constituted the major compounds in old conidia (74%, including 30% of mFA). We have shown for the first time that the total FA composition is strongly correlated with the age of B. graminis f.sp. tritici (Bgt) conidia.     

Seasonal changes of fatty acid composition and thermotropic behavior of polar lipids from marine macrophytes

Major glyco- and phospholipids as well as betaine lipid 1,2-diacylglycero-O-4'-(N,N,N-tri-methyl)-homoserine (DGTS) were isolated from five species of marine macrophytes harvested in the Sea of Japan in summer and winter at seawater temperatures of 20-23 and 3 degrees C, respectively. GC and DSC analysis of lipids revealed a common increase of ratio between n-3 and n-6 polyunsaturated fatty acids (PUFAs) of polar lipids from summer to winter despite their chemotaxonomically different fatty acid (FA) composition. Especially, high level of different n-3 PUFAs was observed in galactolipids in winter. However, the rise in FA unsaturation did not result in the lowering of peak maximum temperature of phase transition of photosynthetic lipids (glycolipids and phosphatidylglycerol (PG)) in contrast to non-photosynthetic ones [phosphatidylcholine (PC) and phosphatidylethanolamine (PE)]. Different thermotropic behavior of these lipid groups was accompanied by higher content of n-6 PUFAs from the sum of n-6 and n-3 PUFAs in PC and PE compared with glycolipids and PG in both seasons. Seasonal changes of DSC transitions and FA composition of DGTS studied for the first time were similar to PC and PE. Thermograms of all polar lipids were characterized by complex profiles and located in a wide temperature range between -130 and 80 degrees C, while the most evident phase separation occurred in PGs in both seasons. Polarizing microscopy combined with DSC has shown that the liquid crystal - isotropic melt transitions of polar lipids from marine macrophytes began from 10 to 30 degrees C mostly, which can cause the thermal sensitivity of plants to superoptimal temperatures in their environment.     

Fatty acids as trophic tracers in an experimental estuarine food chain: Tracer transfer

The transfer of fatty acid (FA) biomarkers was assessed by an experimental food chain comprising three trophic levels: leaves of the mangrove Avicennia marina, the grapsid crab Parasesarma erythodactyla, and the blue swimmer crab Portunus pelagicus. FA compositions for each trophic level were investigated through a feeding/starving regime designed to reveal the transfer of FAs along the food chain. Comparison of the FA profiles of the mangrove leaves, the tissues and faecal material of P. erythodactyla suggests that the crab, contrary to previous studies, lacks the necessary enzymes to incorporate some FAs in its diet. Long chain FAs were egested while polyunsaturated acids seemed to be efficiently assimilated. The polyunsaturated FAs 18:2ω6 and 18:3ω3 were identified as useful biomarkers of the mangrove leaves for tracing their transfer to the higher trophic levels. The contribution of these markers to the FA profiles of the crabs was investigated and it was found that both 18:2ω6 and 18:3ω3 could be successfully traced across the first trophic transfer. However, only 18:3ω3 demonstrated a clear second transfer into the tissues of P. pelagicus. Multivariate analysis of the FA profiles of the study organisms was found to be a potentially useful tool for demonstrating differences in diet within a species and also what FAs, and therefore dietary items, are responsible for those differences. MDS analysis of the FA profiles of faecal material from P. erythodactyla showed that this species provides an important ecological link in estuarine systems by providing a substrate for the colonisation of bacteria.     

Distribution and long-term temporal patterns of four invasive colonial ascidians in the Gulf of Maine

Invasive ascidians are a growing concern for ecologists and natural resource managers, yet few studies have documented their short- and long-term temporal patterns of abundance. This study focuses on the invasion of the Gulf of Maine by the colonial ascidians Botryllus schlosseri, Botrylloides violaceus, Diplosoma listerianum and Didemnum sp. A. We examined the time of arrival and potential vectors for these four invasive ascidians using survey data (collected from 1969 onwards) and literature documentation. We also compared the dominance and seasonal patterns of abundance of these species using data from two identical panel studies; one conducted from 1979 to 1980, the other from 2003 to 2005. Didemnum and Botrylloides were most likely first introduced into the Damariscotta River, Maine in the early 1970's through oyster aquaculture while Botryllus and Diplosoma were probably transported by commercial and recreational vessels. The overall abundance of colonial ascidians has increased since 1979 and 1980. Botryllus was the only invasive colonial ascidian present during the 1979 to 1980 study and accounted for an average of 6.16% cover on panels. From 2003 to 2005, the more recently arrived colonial ascidians Botrylloides and Didemnum accounted for 7.38% and 2.08% cover respectively, while Botryllus covered only 1.16%. Our results reveal a shift in seasonal abundance between 1979 to 1980 and 2003 to 2004. In 1979 and 1980, colonial ascidians had the highest percent cover in fall and winter while in 2003 and 2005 they had highest percent cover in summer and fall. Seasonal patterns of space occupation by colonial ascidians were correlated with seasonal changes in seawater temperature.     

Natural infections of aposymbiotic Cassiopea xamachana scyphistomae from environmental pools of Symbiodinium

The ability to acquire different types of the symbiotic dinoflagellate Symbiodinium (zooxanthellae) from the environment was investigated using aposymbiotic scyphistomae of the jellyfish Cassiopea xamachana. Non-symbiotic scyphistomae were placed on an offshore Florida patch reef and in Florida Bay during 3- and 5-day periods in March, and 5-day exposures in May, August and December of 2003. Scyphistomae were maintained in culture for several months, after which members of clades A, B, C and D Symbiodinium were detected in these hosts by denaturing gradient gel electrophoresis (DGGE) analyses. These findings contrast with naturally collected C. xamachana medusa from Florida Bay where all specimens possessed only Symbiodinium type A1. Furthermore, the polyps did not acquire the symbionts found in nearby cnidarian colonies, suggesting that a diverse pool of symbiont lineages exists in the environment. These results support previous laboratory studies where aposymbiotic hosts were initially non-selective and capable of acquiring many kinds of Symbiodinium. The specificity seen in adult hosts is likely a result of post-infection processes due to competitive exclusion or other mechanisms. A higher percentage of polyps became infected after 5 days of exposure, compared to 3 days, and no infections were observed in laboratory controls held in filtered seawater. Infections were lowest (50% at both sites) in March of 2003, when seawater temperatures were at their annual minima. Infection was 100% in scyphistomae exposed for 5 days during the months of May, August and December of 2003. These findings suggest that this host system, in addition to addressing questions of host-symbiont selectivity, can be employed to monitor and define the abundance and distribution of natural pools of Symbiodinium.     

Oviposition deterrents in larval frass of the cotton boll worm, Helicoverpa armigera (Lepidoptera: Noctuidae): chemical identification and electroantennography analysis

Oviposition deterrents in the frass of cotton bollworm (CBW), Helicoverpa armigera larvae fed on an artificial diet (FA) and on cotton Gossypium hirsutum leaves (FC) were investigated by behavioral bioassays and electroantennography analyses in the laboratory. It was found that a water suspension or a hexane extract of the frass FA or FC, in contrast to the corresponding foods, significantly deterred oviposition of conspecifics. When hexane extracts of the frass FA and FC were further partitioned into polar and neutral lipid fractions, two polar fractions significantly reduced oviposition. The neutral fraction from frass FC also exhibited significant deterrence, although the activity was much lower than that of the corresponding polar fraction. The polar lipid fractions contained several fatty acids, mainly palmitic and oleic acid at the ratio nearly 1:1. A blend of authentic fatty acids of the same composition found in frass FA or FC mimicked the deterring effect. Moreover, these fatty acids and their blend at the ratio found in frass FA or FC elicited significant electroantennogram responses and typical dose-response curves. Thus, it is suggested that CBW larvae may deploy two types of oviposition deterrents: a non-specific and a specific one. The former is a blend of fatty acids, independent of food and plays an important role in oviposition deterrence, whereas the latter may be produced only when the larvae feed on cotton leaves. The possible explanations of this deployment have also been discussed.     

Final steps in juvenile hormone biosynthesis in the desert locust, Schistocerca gregaria

Two genes coding for enzymes previously reported to be involved in the final steps of juvenile hormone (JH) biosynthesis in different insect species, were characterised in the desert locust, Schistocerca gregaria. Juvenile hormone acid O-methyltransferase (JHAMT) was previously described to catalyse the conversion of farnesoic acid (FA) and JH acid to their methyl esters, methyl farnesoate (MF) and JH respectively. A second gene, CYP15A1 was reported to encode a cytochrome P450 enzyme responsible for the epoxidation of MF to JH. Additionally, a third gene, FAMeT (originally reported to encode a farnesoic acid methyltransferase) was included in this study. Using q-RT-PCR, all three genes (JHAMT, CYP15A1 and FAMeT) were found to be primarily expressed in the CA of the desert locust, the main biosynthetic tissue of JH. An RNA interference approach was used to verify the orthologous function of these genes in S. gregaria. Knockdown of the three genes in adult animals followed by the radiochemical assay (RCA) for JH biosynthesis and release showed that SgJHAMT and SgCYP15A1 are responsible for synthesis of MF and JH respectively. Our experiments did not show any involvement of SgFAMeT in JH biosynthesis in the desert locust. Effective and selective inhibitors of SgJHAMT and SgCYP15A1 would likely represent selective biorational locust control agents.     

The effects of dietary supplementation of algae and synthetic astaxanthin on body astaxanthin, survival, growth, and low dissolved oxygen stress resistance of kuruma prawn, Marsupenaeus japonicus Bate

Natural carotenoids from astaxanthin containing alga Haematococcus pluvialis (H) and a non-astaxanthin carotenoid-containing alga Spirulina pacifica (S), and a synthetic astaxanthin Carophyll Pink (A) were supplemented in formulated diets at two concentrations, 50 (I) and 100 (II) mg kg⁻¹, resulting in seven pigmented diets HI, SI, AI, HII, SII, AII, and HS (H-50 mg kg⁻¹+S-50 mg kg⁻¹). Formulated diet without carotenoid supplementation served as a control (C). The different diets were fed to juvenile kuruma prawn Marsupenaeus japonicus for 9 weeks. Dietary carotenoid effects on survival, growth, and pigmentation were compared by the treatment individually or collectively. A low dissolved oxygen stress test was conducted 2 weeks later and prawns' survival time and oxygen consumption rate were also compared among treatments. After 9 weeks' rearing, C-fed prawn had significantly lower survival rate than the pigmented diets-fed prawns. No difference in weight gain was found among all prawns. C-fed prawn had 66.4% less flesh astaxanthin (FA) and 75.5% less shell astaxanthin (SA) than the pigmented diets-fed prawns. I-fed (AI, HI, and SI) prawns had 31.1% less FA and 29.6% less SA than II-fed (AII, HII, SII, and HS) prawns. No significant differences were found in the comparisons by other categories. The use of these three sources of carotenoids for pigmentation in crustacean was discussed along carotenoid conversion, deposition, digestibility, and absorption. When subjected to low dissolved oxygen stress, C-fed prawn had higher oxygen consumption rate (OCR) and shorter survival time (ST) than the prawns fed the pigmented diets. No differences in OCR or ST were found in the comparisons by other categories.     

Evidence for complete epistasis of null mutations in murine Fanconi anemia genes Fanca and Fancg

Fanconi anemia (FA) is a heritable disease characterized by bone marrow failure, congenital abnormalities, and cancer predisposition. The 15 identified FA genes operate in a molecular pathway to preserve genomic integrity. Within this pathway the FA core complex operates as an ubiquitin ligase that activates the complex of FANCD2 and FANCI to coordinate DNA repair. The FA core complex is formed by at least 12 proteins. However, only the FANCL subunit displays ubiquitin ligase activity. FANCA and FANCG are members of the FA core complex for which no other functions have been described than to participate in protein interactions. In this study we generated mice with combined null alleles for Fanca and Fancg to identify extended functions for these genes by characterizing the double mutant mice and cells.Double mutant a^−/−/g^−/− mice were born at near Mendelian frequencies without apparent developmental abnormalities. Histological analysis of a^−/−/g^−/− mice revealed a Leydig cell hyperplasia and frequent vacuolization of Sertoli cells in testes, while ovaries were depleted from developing follicles and displayed an interstitial cell hyperplasia. These gonadal aberrations were associated with a compromised fertility of a^−/−/g^−/− males and females. During the first year of life a^−/−/g^−/− did not develop malignancies or bone marrow failure. At the cellular level a^−/−/g^−/−, Fanca^−/−, and Fancg^−/− cells proved equally compromised in DNA crosslink and homology-directed repair. Overall the phenotype of a^−/−/g^−/− double knockout mice and cells appeared highly similar to the phenotype of Fanca or Fancg single knockouts. The lack of an augmented phenotype suggest that null mutations in Fanca or Fancg are fully epistatic, making additional important functions outside of the FA core complex highly unlikely.     

Interspecific variability of RAPD and fatty acid composition of some pomegranate cultivars (Punica granatum L.) growing in Southern Anatolia Region in Turkey

The interspecific variability of fatty acid (FA) composition and RAPD profiles was used to examine biochemical and genetic relationships among six pomegranate cultivars, which dominate pomegranate production in Southern Anatolia Region of Turkey. Fatty acid composition of pomegranate leaves was determined by using gas chromatography. Differences in the FA composition were found among cultivars. In particular, cv. kirli hanim had a distinct fatty acid profile that differs from the other cultivars. Linoleic acid was not detected in this cultivar, whereas the other cultivars had various levels of linoleic acid. RAPD data also showed that this cultivar formed a unique pattern. The differences in the composition of fatty acids among pomegranate cultivars suggested that fatty acid profiles could be used to differentiate among some of the pomegranate cultivars. RAPD analysis was also useful for grouping the pomegranate cultivars.     

Fatty acid composition in adductor muscle of juvenile scallops (Pecten maximus) from five Norwegian populations reared in the same environment

Adductor muscle fatty acid (FA) composition was compared in Pecten maximus juveniles originating from five locations along the Norwegian coast from 59°N to 65°N to detect possible population differences. Broodstock sized scallops were translocated to sea conditions by a scallop hatchery near Bergen (60°N) before spawning in February 2006. The scallop larvae and juveniles were reared in the same environment for two years and 10 individuals from each population were sampled in May 2007 and in May 2008 for analysis of the FAs in the adductor muscle. The total lipid content determined as total amount of FAs were 5.7 ± 0.3 mg per g tissue, and no significant difference was found among the five populations. The polyunsaturated FAs made up close to 60% of the total, with 20:5n3 and 22:6n3 dominating. The saturated FA content was approximately 30%, while the monounsaturated FA were less abundant (7–10%). The FA composition of the muscles of the five populations was similar within each year, with larger differences between the years. Multivariate, supervised learning method PLS, applied pairwise, showed distinct FA composition, between the scallops from the five locations, indicating population differences. The relatedness between the populations was different in the two years, but the distinct FA profiles of the adductor muscle could be used to distinguish between scallop populations on a local scale. The results indicate habitat-specific lipid metabolism which may have important implications for the scallop aquaculture industry in the context of producing well adapted individuals for the specific locations.     

A comparison of the thermal bleaching responses of the zoanthid Palythoa caribaeorum from three geographically different regions in south Florida

Coral bleaching involves the loss of symbiotic algae (zooxanthellae) from reef corals and other cnidarians during periods of environmental stress, particularly elevated temperature. In this study we compared the thermal bleaching responses of the zoanthid Palythoa caribaeorum from three populations along the southeast coast of Florida. Winter (2002-2003) and summer (2003) samples from three geographically separate sites were experimentally exposed to increased temperatures and the loss of zooxanthellae was measured. Population densities of zooxanthellae were analyzed and their genetic identity determined using PCR-DGGE analysis of the internal transcribed spacer region 2. The results showed that samples of P. caribaeorum from reefs that experienced the smallest range in annual seawater temperature released the most zooxanthellae. Seasonal comparisons revealed that winter samples lost more zooxanthellae than summer samples. P. caribaeorum harbored two genetic types of zooxanthellae, C1 and D1a. Individual colonies contained populations of only C1 or D1a, or combinations of C1 and D1a. However, these genotypic patterns did not relate latitudinal distribution nor to differences in experimental thermal tolerance.     

High gametocyte complexity and mosquito infectivity of Plasmodium falciparum in the Gambia

The purpose of this work was to determine the infectivity to mosquitoes of genetically diverse Plasmodium falciparum clones seen in natural infections in the Gambia. Two principal questions were addressed: (i) how infectious are gametocytes of sub-patent infections, particularly at the end of the dry season; and (ii) are all clones in multiclonal infections equally capable of infecting mosquitoes? The work was carried out with two cohorts of infected individuals. Firstly, a group of 31 P. falciparum-infected people were recruited in the middle of the dry season (May, 2003), then examined for P. falciparum at the beginning (August 2003) and middle (October, 2003) of the transmission season. On each occasion, we examined the genotypes of asexual forms and gametocytes by PCR and RT-PCR, as well as their infectivity to Anopheles gambiae using membrane feeds. One individual gave rise to infected mosquitoes in May, and two in August. Different gametocyte genotypes co-existed in the same infection and fluctuated over time. The mean multiplicity of infection was 1.4, 1.7 and 1.5 clones in May, August and October, respectively. Second, a group of patients undergoing drug-treatment during August 2003 was tested for asexual and gametocyte genotypes and their infectivity to mosquitoes. Forty-three out of 100 feeds produced infections. The genetic complexity of the parasites in mosquitoes was sometimes greater than that detectable in the blood on which the mosquitoes had fed. This suggested that gametocytes of clones existing in the blood below PCR detection limits at the time of the feed were at least as infectious to the mosquitoes as the more abundant clones. These findings emphasise the crucial role of gametocyte complexity and infectivity in generating the remarkable diversity of P. falciparum genotypes seen in infected people, even in an area of seasonal transmission.     

Epizootiological studies of Amblyospora camposi (Microsporidia: Amblyosporidae) in Culex renatoi (Diptera: Culicidae) and Paracyclops fimbriatus fimbriatus (Copepoda: Cyclopidae) in a bromeliad habitat

The epizootiology of Amblyospora camposi was studied in a natural population of Culex renatoi, a bromeliad-inhabiting mosquito, and its intermediate host, Paracyclops fimbriatus fimbriatus, over a 2-year period. Twenty Eryngium cabrerae plants were sampled monthly from January 2003 to January 2005 and the prevalence of A. camposi in P.f. fimbriatus and Cx. renatoi populations was determined. The monthly prevalence rates of meiospore infections in Cx. renatoi larvae never exceeded 5.5% and was detected in 50% of the monthly samples. Meiospores were available in plants over the course of the study at a mean concentration of 2 x 10(4) meiospores/ml. Within each plant the parasite was maintained by horizontal transmission. P.f. fimbriatus with vegetative stages and mature spores were found regularly in bromeliads suggesting efficient meiospore infectivity to field copepod populations. The mean concentration of spores from copepods found in plants was 8 x 10(2) spores/ml. Infections in copepods were detected in 54% of the monthly samples with a prevalence rate ranging from 0.55 to 17.4% and an overall average of 5.1%. Vegetative stages in fourth instar mosquito larvae (probably derived from the horizontal pathway via spores formed in copepods) were detected in 12.5% of the monthly samples with an overall prevalence rate of 1.1%. Infections in female and male adults were detected in 20.8% of the monthly samples with an overall average of 4.1% and 6.8%, respectively.     

Fatty acid composition of individual polar lipid classes from marine macrophytes

Major glycolipids [monogalactosyldiacylglycerol (MGDG), digalactosyldiacylglycerol (DGDG), sulfoquinovosyldiacylglycerol (SQDG)) and phospholipids (phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylglycerol (PG)] as well as betaine lipid 1,2-diacylglycero-O-4'-(N,N,N-tri-methyl)-homoserine (DGTS) were isolated from Anfeltia tobuchiensis (Rhodophyta), Laminaria japonica, Sargassum pallidum (Phaeophyta), Ulva fenestrata (Chlorophyta) and Zostera marina (Embriophyta), harvested in the Sea of Japan. GC analysis of their fatty acid (FA) composition revealed that the n-6 polyunsaturated FAs (PUFAs) shared the most part of the sum of n-6 and n-3 PUFAs in PC and PE compared with glycolipids and PG. In algae, it was related to the prevalence of 20:4n-6 over 20:5n-3 in non-photosynthetic lipids. Percentage of n-6 PUFAs as well as the sum of n-3 and n-6 PUFAs decreased in the following sequence: PC-->PE-->PG. The saturation increased in the lines of MGDG-->DGDG-->SQDG and PC-->PE-->PG. PG was close to SQDG by the level of saturation. Distribution of C(18) and C(20) PUFAs in polar lipids depended on taxonomic position of macrophytes. Balance between C(18) and C(20) PUFAs was preferably shifted to the side of C(20) PUFAs in PC and PE that was observed in contrast to glycolipids and PG from L. japonica containing both series of FAs. The set of major FAs of polar lipid classes can essentially differ from each other and from total lipids of macrophytes. For example, MGDG was found to accumulate characteristic fatty acids 16:4n-3, 16:3n-3, 18:3n-6 and 18:4n-3, 20:3n-6 in U. fenestrata, Z. marina, L. japonica and S. pallidum, respectively.     

An investigation on the antioxidant status of the invasive alga Caulerpa racemosa var. cylindracea (Sonder) Verlaque, Huisman, et Boudouresque (Caulerpales, Chlorophyta)

Caulerpa racemosa var. cylindracea is a potential invader of the Mediterranean Sea and 11 Mediterranean countries are under threat from this alga. In the present study, in order to investigate seasonal changes in the antioxidant status of C. racemosa var. cylindracea, antioxidant enzyme activities such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and lipid peroxidation (LPO) levels were determined in C. racemosa var. cylindracea samples, which were collected in May 2003, September 2003, December 2003, and March 2004 from Turkish coastlines. SOD and CAT activities showed similar trends. These enzymes increased from May to December, then sharp decreases were observed. On the other hand, GSH-Px enzyme activities showed a fluctuation between May 2003 and March 2004. In contrast to increases in SOD and CAT activities up to December 2003, LPO level decreased in this period. No significant correlation was observed between antioxidant status and solar radiation. In conclusion, the antioxidant status of C. racemosa var. cylindracea is strictly not affected by both solar radiation and seawater temperature; however, the growth of epiphytes on fronds may change antioxidant status. Further investigations are strongly warranted to understand the contributions of non-enzyme-based antioxidants such as glutathione, vitamin E, and vitamin C.     

Inhibition of inflammatory response in transgenic fat-1 mice on a calorie-restricted diet

Both n-3 fatty acids (n-3 FA) and calorie-restriction (CR) exert anti-inflammatory effects in animal models of autoimmunity and inflammation. In the present study we investigated the synergistic anti-inflammatory effects of n-3 FA and CR on LPS-mediated inflammatory responses using fat-1 transgenic mice that generate n-3 FA endogenously. Wild-type (WT) and fat-1 mice were maintained on ad libitum (AL) or CR (40% less than AL) diet for 5 mo; splenocytes were cultured in vitro with/without LPS. Our results show: (i) no difference in body weights between WT and fat-1 mice on AL or CR diets, (ii) lower n-6/n-3 FA ratio in splenocytes from fat-1 mice on both AL and CR diets, (iii) significant reduction in NF-kappaB (p65/p50) and AP-1 (c-Fos/c-Jun) DNA-binding activities in splenocytes from fat-1/CR mice following LPS treatment, and (iv) significant reduction in kappaB- and AP-1-responsive IL-6 and TNF-alpha secretion following LPS treatment in splenocytes from fat-1/CR mice. The inhibition of LPS-mediated effects was more pronounced in fat-1/CR mice when compared to fat-1/AL or WT/CR mice. These data show that transgenic expression of fat-1 results in decreased pro-inflammatory n-6 FA, and demonstrate for the first time that splenocytes from fat-1 mice on CR diet exhibit reduced pro-inflammatory response when challenged with LPS. These results suggest that n-3 lipids with moderate CR may confer protection in autoimmune and inflammatory diseases.     

Effects of native and invasive macroalgal canopies on composition and abundance of mobile benthic macrofauna and turf-forming algae

We examined the effects of native kelps, Laminaria longicruris de la Pylaie and L. digitata (Hudson) Lamouroux, and of the invasive alga, Codium fragile ssp. tomentosoides (Van Goor) Silva, on the composition and abundance of mobile benthic macrofauna and of turf algae by measuring the response of these assemblages to experimental removal of the respective macroalgal canopy. From June 2003 to November 2004, we censused macrofauna and measured canopy cover within 4 × 10 m strips of alternating Canopy Intact (control) and Canopy Removed treatments in both a Codium- and a Laminaria-dominated habitat in the rocky subtidal zone of a semi-protected embayment on the Atlantic coast of Nova Scotia, Canada. Macroalgal canopy cover fluctuated seasonally, peaking in September/October (69% cover in 2003; 55% cover in 2004) for Codium and in May 2004 (70% cover) for kelps, and with both canopy types reaching a winter minimum in January 2004 (22 and 28% cover, respectively). In both Codium and Laminaria habitats, significant effects of canopy removal on the overall macrofaunal assemblage were evident only during periods in which canopy cover in the Canopy Intact treatment was ≥ 50%. In the Codium habitat, 4 out of 11 characteristic taxa were more abundant in the Canopy Intact treatment, where taxonomic diversity also was higher. In contrast, 4 out of 11 characteristic taxa in the Laminaria habitat were more abundant in the Canopy Removed treatment and diversity was similar between treatments. Turf algae were sampled in November 2004 and, despite between-treatment differences in the light regime, there was no significant effect of canopy removal. Our results indicate that selection of algal habitats by mobile macrofauna is likely determined by the different shelter and foraging opportunities offered by these morphologically dissimilar ecosystem engineers.     

Occurrence of Halophila baillonii meadows in Belize,Central America

Halophila baillonii Ascherson was found in Belize, Central America in 2003 and 2005. The observation extends the known range of this seagrass species to the western Caribbean. H. baillonii was previously recorded only in the eastern Caribbean and at one Pacific site in Panama. Both fruits and flowers of H. baillonii were observed at two locations in Belize in 2005. H. baillonii in Belize is an important food for manatee, forms a productive seagrass-based ecosystem, and is adversely affected by shoreline development and watershed run-off.