The influence of brown algae alginates on phenolic compounds capability of ultraviolet radiation absorption in vitro

Os compostos fenólicos (PC) de algas pardas são metabólitos secundários que participam de diversos processos biológicos, como proteção contra radiação ultravioleta (UV), bloqueio de poliespermia e ligação de metais. Recentemente, os PC têm sido estudados devido a possíveis interações com polissacarídeos da parede celular. Entretanto, existem poucas evidências sobre estas interações e sua influência em processos fisiológicos. Neste trabalho, foram investigadas as interações entre os PC de Padina gymnospora e os alginatos e a influência destas interações na capacidade de absorção de UV pelos PC. Foram utilizadas técnicas cromatográficas e espectrofotométricas para o isolamento, a caracterização e a determinação da capacidade de absorção de UV dos compostos estudados. Mesmo após a extração dos polissacarídeos de P. gymnospora e a utilização dos métodos de isolamento, os PC permaneceram ligados ao alginato. A interação de alginato com PC não causou modificações no padrão de absorção do espectro eletromagnético (UV-VIS-IR). A capacidade de absorção de UV dos PC ligados aos alginatos foi mantida por um tempo mais longo do que a do extrato de PC puros. Os resultados obtidos demonstram que há uma forte ligação entre PC e alginatos e que estas ligações preservam a capacidade de absorção de UV dos PC ao longo do tempo.Brown algae phenolic compounds (PC) are secondary metabolites that participate in many biological processes, such as ultraviolet radiation (UV) protection, polyspermy blocking and trace metals bounding. Recently, PC has also been studied due to possible interactions with cell wall polysaccharides. However, there are few evidences of these interactions and their influence in physiological processes. The interactions between PC from the brown alga Padina gymnospora and alginates and the influence of these interactions on the UV absorption properties of PC were investigated in this work. Chromatography and spectrophotometry techniques were used to isolate, characterize and determine UV absorption capacity of studied compounds. Even after the P. gymnospora polysaccharide extraction and isolating methods, the PC was maintained linked to the alginate. The interaction of alginates with PC did not cause modifications on absorbance pattern of electromagnetic spectrum (UV-VIS-IR). The UV absorbance capability of PC linked to alginate was maintained for a longer period of time if compared with the purified PC. The obtained results reveal the strong linkage between PC and alginates and that these linkages preserve the UV absorption capability of PC along time

Chloroplasts morphology investigation with diverse microscopy approaches and inter-specific variation in Laurencia species (Rhodophyta)

The present study described with different microscopy approaches chloroplasts lobes in Laurencia sensu latu (Rhodophyta) species and found inter-specific differences among them. Chloroplasts were investigated using confocal laser scanning microscopy (LSM), transmission electron microscopy (TEM) and high resolution scanning electron microscopy (HRSEM). Using and TEM and HRSEM images we distinguished chloroplasts with lobes than chloroplasts without lobes in Yuzurua poiteaui var. gemmifera (Harvey) M. J. Wynne and Laurencia dendroidea J. Agardh cortical cells. The LSM images showed chloroplasts lobes (CLs) with different morphologies, varying from thicker and longer undulated projections in Y. poiteaui var. and L. dendroidea to very small and thin tubules as in Laurencia translucida Fujii & Cordeiro-Marino. The diameter and length of CLs from Y poiteaui var. and L. dendroidea were significantly higher than L. translucida CLs (p \u3c 0.01). Based on LSM observations, we suggest that lobes morphology has a taxonomic validity only to characterize L. translucida species

Effect of photodynamic therapy with malachite green on non-surgical periodontal treatment in HIV patients : a pilot split-mouth study

A number of oral lesions are among the early features of HIV infection. It has been described that HIV patients are at risk for severe periodontal diseases. In addition, there is a higher prevalence of periodontal pathogens such as Actinobacillus actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), and Tannerella forsythensis (Tf) in HIV patients compared with non-HIV patients. Polymerase chain reaction (PCR) is a diagnostic method that enables assessing microorganisms with very high levels of accuracy. For this reason, PCR is helpful to detect periodontal pathogens at levels below the ones detectable by cell culture or other diagnostic methods. In most cases, the sole use of repeated scaling and root planing (SRP) as periodontal therapy leads to satisfactory clinical outcomes. However, the aforementioned approach may not be enough to achieve periodontal health in more challenging cases, such as residual deep pockets and furcation areas . In addition, SRP often needs to be followed by adjunctive therapy such as local delivery and systemic antimicrobials and host modulation. One of the most recent methods used in combination with SRP in the periodontal treatment is the photodynamic therapy (PDT). In PDT, a photosensitizing agent is used to apply light therapy selectively to target specific cells. It is useful for sensitizing bacterial cells, leading to effective antimicrobial activity due to the production of cytotoxic oxygen free radicals (singlet oxygen). However, the efficacy of PDT is dependent on various factors, such as the laser wavelength and its interaction with the photosensitizer. One of the photosensitizers that have been used for the aforementioned purpose is the malachite green (MG), which leads to dissipation of the cell membrane potential in both gram-positive and - negative bacterial species. MG is defined as a cationic dye of the triarylmethane family that shows satisfactory absorption at the red end of the visible spectrum. However, little is known on the effect of PDT with MG as an adjunctive periodontal treatment in combination with SRP. Thus, the aim of this pilot split-mouth study was to assess clinical and microbiological effects of PDT with MG on non-surgical periodontal treatment in HIV patients.peer-reviewe

Utilização da tomografia computadorizada de feixe cônico na obtenção de índices radiomorfométricos – Revisão de Literatura

Diferentes índices quantitativos e qualitativos são utilizados para mensurar a qualidade óssea em radiografia panorâmicas, e são denominados, índices radiomorfométricos. Esses índices são propostos como ferramentas de rastreio da baixa densidade mineral óssea e da osteoporose, sendo considerados como métodos alternativos. Atualmente pesquisadores têm utilizado esses índices em tomografias computadorizadas de feixe cônico (TCFC), com o intuito de verificar se esse exame também pode ser utilizado para busca de pacientes com baixa densidade mineral óssea. O objetivo desse estudo, foi fazer uma revisão de literatura a respeito do uso da TCFC para a obtenção dos índices. Foram selecionados trabalhos que abordaram o uso da TCFC e índices radiomorfométricos para análise da qualidade óssea. Conclui-se que os índices radiomorfométricos podem ser obtidos em exames de TCFC, porém mais estudos são necessários devido a variabilidade de metodologias e parâmetros.

Extensive Rhodolith Beds Cover the Summits of Southwestern Atlantic Ocean Seamounts

Calcium carbonate production by marine organisms is an essential process in the global budget of CO32-, and coralline reefs are the most important benthic carbonate producers. Crustose coralline algae (CCA) are well recognized as the most important carbonate builders in the tropical Brazilian continental shelf, forming structural reefs and extensive rhodolith beds. However, the distribution of CCA beds, as well as their role in CO32- mineralization in mesophotic communities and isolated carbonate banks, is still poorly known. To characterize the bottom features of several seamount summits in the Southwestern Atlantic (SWA), side-scan sonar records, remotely operated vehicle imagery, and benthic samples with mixed-gas scuba diving were acquired during two recent research cruises (March 2009 and February 2011). The tops of several seamounts within this region are relatively shallow (similar to 60 m), flat, and dominated by rhodolith beds (Vitoria, Almirante Saldanha, Davis, and Jaseur seamounts, as well as the Trindade Island shelf). On the basis of abundance, dimensions, vitality, and growth rates of CCA nodules, a mean CaCO3 production was estimated, ranging from 0.4 to 1.8 kg m(-2) y(-1) with a total production reaching 1.5 x 10(-3) Gt y(-1). Our results indicate that these SWA seamount summits provide extensive areas of shallow reef area and represent 0.3% of the world's carbonate banks. The importance of this habitat has been highly neglected, and immediate management needs must be fulfilled in the short term to ensure long-term persistence of the ecosystem services provided by these offshore carbonate realms.Brazilian Research Council (CNPq)Brazilian Research Council (CNPq

Long-term effects of competition and environmental drivers on the growth of the endangered coral Mussismilia braziliensis (Verril, 1867)

Most coral reefs have recently experienced acute changes in benthic community structure, generally involving dominance shifts from slow-growing hard corals to fast-growing benthic invertebrates and fleshy photosynthesizers. Besides overfishing, increased nutrification and sedimentation are important drivers of this process, which is well documented at landscape scales in the Caribbean and in the Indo-Pacific. However, small-scale processes that occur at the level of individual organisms remain poorly explored. In addition, the generality of coral reef decline models still needs to be verified on the vast realm of turbid-zone reefs. Here, we documented the outcome of interactions between an endangered Brazilian-endemic coral (Mussismilia braziliensis) and its most abundant contacting organisms (turf, cyanobacteria, corals, crustose coralline algae and foliose macroalgae). Our study was based on a long (2006–2016) series of high resolution data (fixed photoquadrats) acquired along a cross-shelf gradient that includes coastal unprotected reefs and offshore protected sites. The study region (Abrolhos Bank) comprises the largest and richest coralline complex in the South Atlantic, and a foremost example of a turbid-zone reef system with low diversity and expressive coral cover. Coral growth was significantly different between reefs. Coral-algae contacts predominated inshore, while cyanobacteria and turf contacts dominated offshore. An overall trend in positive coral growth was detected from 2009 onward in the inshore reef, whereas retraction in live coral tissue was observed offshore during this period. Turbidity (+) and cyanobacteria (−) were the best predictors of coral growth. Complimentary incubation experiments, in which treatments of Symbiodinium spp. from M. braziliensis colonies were subjected to cyanobacterial exudates, showed a negative effect of the exudate on the symbionts, demonstrating that cyanobacteria play an important role in coral tissue necrosis. Negative effects of cyanobacteria on living coral tissue may remain undetected from percent cover estimates gathered at larger spatial scales, as these ephemeral organisms tend to be rapidly replaced by longer-living macroalgae, or complex turf-like consortia. The cross-shelf trend of decreasing turbidity and macroalgae abundance suggests either a direct positive effect of turbidity on coral growth, or an indirect effect related to the higher inshore cover of foliose macroalgae, constraining cyanobacterial abundance. It is unclear whether the higher inshore macroalgal abundance (10–20% of reef cover) is a stable phase related to a long-standing high turbidity background, or a contemporary response to anthropogenic stress. Our results challenge the idea that high macroalgal cover is always associated with compromised coral health, as the baselines for turbid zone reefs may derive sharply from those of coral-dominated reefs that dwell under oligotrophic conditions

Rhodolith Beds Are Major CaCO3 Bio-Factories in the Tropical South West Atlantic

Rhodoliths are nodules of non-geniculate coralline algae that occur in shallow waters (<150 m depth) subjected to episodic disturbance. Rhodolith beds stand with kelp beds, seagrass meadows, and coralline algal reefs as one of the world's four largest macrophyte-dominated benthic communities. Geographic distribution of rhodolith beds is discontinuous, with large concentrations off Japan, Australia and the Gulf of California, as well as in the Mediterranean, North Atlantic, eastern Caribbean and Brazil. Although there are major gaps in terms of seabed habitat mapping, the largest rhodolith beds are purported to occur off Brazil, where these communities are recorded across a wide latitudinal range (2°N - 27°S). To quantify their extent, we carried out an inter-reefal seabed habitat survey on the Abrolhos Shelf (16°50′ - 19°45′S) off eastern Brazil, and confirmed the most expansive and contiguous rhodolith bed in the world, covering about 20,900 km2. Distribution, extent, composition and structure of this bed were assessed with side scan sonar, remotely operated vehicles, and SCUBA. The mean rate of CaCO3 production was estimated from in situ growth assays at 1.07 kg m−2 yr−1, with a total production rate of 0.025 Gt yr−1, comparable to those of the world's largest biogenic CaCO3 deposits. These gigantic rhodolith beds, of areal extent equivalent to the Great Barrier Reef, Australia, are a critical, yet poorly understood component of the tropical South Atlantic Ocean. Based on the relatively high vulnerability of coralline algae to ocean acidification, these beds are likely to experience a profound restructuring in the coming decades