Use of FTIR,FT-Raman and 13C-NMR spectroscopy for identification of some seaweed phycocolloids

Many seaweeds produce phycocolloids, stored in the cell wall. Members of the Rhodophyceae produce polysaccharides the main components of which are galactose (galactans)-agar and carrageenan. In addition, alginic acid is extracted from members of the Phaeophyceae. This is a binary polyuronide made up of mannuronic acid and guluronic acid. The wide uses of these phycocolloids are based on their gelling, viscosifying and emulsifying properties, which generate an increasing commercial and scientific interest. In this work, the FTIR and FT-RAMAN spectra of carrageenan and agar, obtained by alkaline extraction from different seaweeds (e.g. Mastocarpus stellatus, Chondrus crispus, Calliblepharis jubata, Chondracanthus acicularis, Chondracanthus teedei and Gracilaria gracilis), were recorded in order to identify the type of phycocolloid produced. The spectra of commercial carrageenan, alginic acid and agar samples (SIGMA and TAAB laboratories) were used as references. Special emphasis was given to the 500-1500 cm(-1) region, which presents several vibrational modes, sensitive to the type of polysaccharide and to the type of glycosidic linkage. The FT-Raman spectra present a higher resolution than FTIR spectra, this allowing the identification of a larger number of characteristic bands. In some cases, phycocolloids can be identified by FT-Raman spectroscopy alone.     

Enhancing knowledge on low-value fishing species: the distinct reproductive strategy of two gurnard species

The depletion and overexploitation of several fish stock demands for a valorisation of non-target and discarded species. Nonetheless, such species are often poorly studied, and information on their biological parameters must be gathered for effective population management. For 1 year, the reproductive strategy of the piper gurnard Trigla lyra and the red gurnard Chelidonichthys cuculus was studied by monthly samples obtained from commercial boats operating on western Portuguese coast. Both species showed a biased sex ratio towards females, especially for larger length classes. Length at first maturity could be estimated only for red gurnard (22.1 and 19.9 cm for females and males, respectively) because all piper gurnard individuals caught were mature. Piper gurnard showed determinate fecundity and a short spawning season, from November to February with a peak in January, whereas red gurnard showed indeterminate fecundity and a wide spawning season, from late December to May. The relative annual fecundity estimated for red gurnard (1893 ± 728 oocytes × g⁻¹ eviscerated weight [EW]) was higher than the one estimated for piper gurnard (1018 ± 250 oocytes×g⁻¹ EW). Although important information for understanding the species dynamics is presented in this study, additional information on other life-history parameters and of species landings is required.     

Synthesis and Phosphorylation of Maize Acidic Ribosomal Proteins : Implications in Translational Regulation

The objective of this research was to determine the role of acidic ribosomal protein (ARP) phosphorylation in translation. Ribosomes (Rbs) from germinated maize (Zea mays L.) axes had four ARP bands within 4.2 to 4.5 isoelectric points when analyzed by isoelectric focusing. Two of these bands disappeared after alkaline phosphatase hydrolysis. During germination a progressive change from nonphosphorylated (0 h) to phosphorylated ARP (24 h) forms was observed in the Rbs; a free cytoplasmic pool of nonphosphorylated ARPs was also identified by immunoblot and isoelectric focusing experiments. De novo ARP synthesis initiated very slowly early in germination, whereas ARP phosphorylation occurred rapidly within this period. ARP-phosphorylated versus ARP-nonphosphorylated Rbs were tested in an in vitro reticulocyte lysate translation system. Greater in vitro mRNA translation rates were demonstrated for the ARP-phosphorylated Rbs than for the non-ARP-phosphorylated ones. Rapamycin application to maize axes strongly inhibited S6 ribosomal protein phosphorylation, but did not interfere with the ARP phosphorylation reaction. We conclude that ARP phosphorylation does not depend on ARP synthesis or on ARP assembly into Rbs. Rather, this process seems to be part of a translational regulation mechanism.     

The pineal complex: a morphological and immunohistochemical comparison between a tropical (Paracheirodon axelrodi) and a subtropical (Aphyocharax anisitsi) characid species

Cardinal neon Paracheirodon axelrodi and bloodfin tetra Aphyocharax anisitsi are two species of characids with high trade value as ornamental fish in South America. Although both species inhabit middle water layers, cardinal neon exhibits a tropical distribution and bloodfin tetra a subtropical one. In this work, we carried out an anatomical, histological and immunohistochemical study of the pineal complex of P. axelrodi and A. anisitsi. In both species, the pineal complex consisted of three components, the pineal and parapineal organs and the dorsal sac (DS). The pineal organ was composed of a short, thin pineal stalk (PS), vertically disposed with respect to the upper surface of the telencephalon, and a pineal vesicle (PV), located at the distal end of the PS and attached to the skull by connective tissue. The pineal window (PW), a site in the skull where the luminal information accesses the pineal organ, appeared just above the latter structures. In the epidermis of P. axelrodi's PW, club cells were identified, but were not observed in the epidermis of A. anisitsi's one. With respect to the DS, it appeared to be folded on itself, and was bigger and more folded in A. anisitsi than in P. axelrodi. Immunohistochemical assays revealed the presence of cone opsin‐like and rod opsin‐like photoreceptor cells in the PS and PV. These results provide a first insight into the morphological assembly of the pineal complex of both species, and contribute to a better understanding of the integration and transduction of light stimuli in characids. J. Morphol. 277:1355–1367, 2016. © 2016 Wiley Periodicals, Inc.     

The invasive brown seaweed Sargassum muticum as new resource for alginate in Morocco: Spectroscopic and rheological characterization

The Japanese brown seaweed Sargassum muticum, recently invaded several shorelines worldwide including the Atlantic coast of Morocco with large well‐established populations. Within the framework of a sustainable strategy to control this invasive seaweed, we report on extraction yield, spectroscopic characterization and rheological properties of alginate, a commercially valuable colloid, from harvested biomass of S. muticum. Extraction yield was about 25.6% on dry weight basis. Infrared spectroscopy analysis shows that the obtained Fourier transform infrared spectra of the extracted biopolymer exhibit strong similarities with that of the commercial alginate. Furthermore, Proton nuclear magnetic resonance spectroscopy revealed that S. muticum alginate has almost equal amounts of β‐D‐mannuronic acid (M; 49%) and α‐L‐guluronic acid (G; 51%) with an M/G ratio of 1.04 and a high content of heteropolymeric MG GM diads suggesting a sequence distribution of an alternated polymer type. Rheological measurements were performed at different sodium alginate concentrations, temperatures and shear rates. The hydrocolloid exhibited pseudoplastic behavior and showed shear thinning, particularly at high solution concentration and low temperature which is consistent with the rheological behavior reported for commercial alginates. Considering the abundance of S. muticum in the Northwestern Atlantic coast of Morocco and the quality of the extracted hydrogel, this invasive species could be considered as a potential source of alginates.     

Biological function and molecular mapping of M antigen in yeast phase of Histoplasma capsulatum

Histoplasmosis, due to the intracellular fungus Histoplasma capsulatum, can be diagnosed by demonstrating the presence of antibodies specific to the immunodominant M antigen. However, the role of this protein in the pathogenesis of histoplasmosis has not been elucidated. We sought to structurally and immunologically characterize the protein, determine yeast cell surface expression, and confirm catalase activity. A 3D-rendering of the M antigen by homology modeling revealed that the structures and domains closely resemble characterized fungal catalases. We generated monoclonal antibodies (mAbs) to the protein and determined that the M antigen is present on the yeast cell surface and in cell wall/cell membrane preparations. Similarly, we found that the majority of catalase activity was in extracts containing fungal surface antigens and that the M antigen is not significantly secreted by live yeast cells. The mAbs also identified unique epitopes on the M antigen. The localization of the M antigen to the cell surface of H. capsulatum yeast and the characterization of the protein's major epitopes have important implications since it demonstrates that although the protein may participate in protecting the fungus against oxidative stress it is also accessible to host immune cells and antibody.     

Observations on the life stages of Sphaerothecum destruens n. g., n. sp., a mesomycetozoean fish pathogen formerly referred to as the rosette agent [correction

The rosette agent is an obligate intracellular parasite that causes morbidity and mortality in salmonid fish. In laboratory cultures, the spore stage (2-6 microm diam.) replicates in a salmonid cell line by sequential asexual division, giving rise to daughter cells. If infected cell cultures are transferred to distilled water, the spore stage undergoes internal division to give rise to at least 5 cells each of which develops into a uniflagellated zoospore with a body of approximately 2 microm and a flagellum approximately 10 microm long. Zoosporulation does not occur in cell culture medium alone, artificial seawater, or phosphate-buffered saline. This parasite is currently classified as a member of the Class Mesomycetozoea (formerly Ichthyosporea) based on phylogenetic analyses of the small subunit ribosomal DNA of three different isolates from fish. Given these new morphological observations combined with the available molecular phylogenetic data on other mesomycetozoeans, we propose to classify the rosette agent as Sphaerothecum destruens, n. g., n. sp. This new genus has unique features including (1) intracellular development of spore stages in various organs eliciting a host granulomatous response; and (2) the differentiation of mature spores into multiple, flagellated zoospores. Taken together, these characteristics clearly distinguish it from the closely related genera Dermocystidium and Rhinosporidium.     

The stepwise selection for ketoconazole resistance induces upregulation of C14-demethylase (CYP51) in Leishmania amazonensis

Ketoconazole is a clinically safe antifungal agent that also inhibits the growth of Leishmania spp. A study was undertaken to determine whether Leishmania parasites are prone to becoming resistant to ketoconazole by upregulating C14-demethylase after stepwise pharmacological pressure. Leishmania amazonensis promastigotes [inhibitory concentration (IC)?? = 2 μM] were subjected to stepwise selection with ketoconazole and two resistant lines were obtained, La8 (IC?? = 8 μM) and La10 (IC?? = 10 μM). As a result, we found that the resistance level was directly proportional to the C14-demethylase mRNA expression level; we also observed that expression levels were six and 12 times higher in La8 and La10, respectively. This is the first demonstration that L. amazonensis can up-regulate C14-demethylase in response to drug pressure and this report contributes to the understanding of the mechanisms of parasite resistance.     

Feeding habits of the bluemouth, Helicolenus dactylopterus dactylopterus (Delaroche, 1809) (Pisces: Sebastidae) in the Portuguese coast

In order to investigate the feeding habits of Helicolenus dactylopterus dactylopterus along the continental Portuguese coast, a total of 619 individuals were sampled of which 60% contained food in their stomach and 35% had more than one prey item. Among the 81 prey items that were identified in the stomachs, benthic and benthopelagic prey prevail on this species diet. Acantephyra sp, Pasiphaea sp, mysidacea, and teleostei n.i. were the prey with the higher percent index of relative importance (%IRI) value. Three length groups (5?C20?cm, 21?C27?cm, and 28?C48?cm) were defined through cluster analysis of the mean abundance of prey items. A permutational MANOVA detected significant differences in the diet and stomach fullness index for TLG, season, and maturation stage. Smaller fishes had a generalized diet, feeding mainly on mysidacea changing their diet above 20?cm TL, where a major consumption of natantia was found. The larger individuals, >28?cm TL, present a less generalized diet with pisces as dominant prey group. Seasonally, natantia and pisces were the principal prey groups during spring and winter, respectively, while mysidacea and other crustaceans were predominant during the rest of the year. Mysidacea were also the main prey group for immature individuals while natantia and pisces were the principal prey groups to the other maturity stages. The results of this study indicate that H. d. dactylopterus has a diverse diet focused on small crustaceans such as misyds and as specimens grow shrimps and fishes become more consumed, with larger specimens having a more specialized diet. The different nutritional needs during spawning season also seemed to influence the feeding habits of H. d. dactylopterus.     

The taxonomy and phylogenetics of the human and animal pathogen Rhinosporidium seeberi: A critical review

Rhinosporidum seeberi is the etiologic agent of rhinosporidiosis, a disease of mucous membranes and infrequent of the skin and other tissues of humans and animals. Because it resists culture, for more than 100 years true taxonomic identity of R. seeberi has been controversial. Three hypotheses in a long list of related views have been recently introduced: 1) a prokaryote cyanobacterium in the genus Microcystis is the etiologic agent of rhinosporidiosis, 2) R. seeberi is a eukaryote pathogen in the Mesomycetozoa and 3) R. seeberi is a fungus. The reviewed literature on the electron microscopic, the histopathological and more recently the data from several molecular studies strongly support the view that R. seeberi is a eukaryote pathogen, but not a fungus. The suggested morphological resemblance of R. seeberi with the genera Microcystis (bacteria), Synchytrium and Colletotrichum (fungi) by different teams is merely hypothetical and lacked the scientific rigor needed to validate the proposed systems. A fundamental aspect against the prokaryote theory is the presence of nuclei reported by numerous authors and updated in this review. Moreover, Microcystis's and Synchytrium's ultra-structural and key cell cycle traits cannot be found in R. seeberi parasitic phase. The PCR amplification of a cyanobacteria 16S rDNA sequence from cases of rhinosporidiosis, while intriguing, will be viewed here as an anomaly due to contamination with environmental Microcystis or perhaps as an endosymbiotic acquisition of plastids from cyanobacteria ancestors. Thus, even if R. seeberi possesses prokaryote DNA, this does not prove that R. seeberi is a cyanobacterium. The placement of R. seeberi within the fungi is scientifically untenable. The isolation and the DNA analysis performed in a fungal strain, and the lack of appropriate controls are the main problems of this claim. Further studies are needed to validate R. seeberi's acquisition of prokaryote plastids and other issues that still need careful scrutiny.