Drivers of phytoplankton diversity in Lake Tanganyika

In keeping with the theme of this volume, the present article commemorates the 50 years of Hutchinson’s (Am Nat 93:145–159, 1959) famous publication on the ‘very general question of animal diversity’, which obviously leads to the more important question regarding the driving forces of biodiversity and their limitation in various habitats. The study of phytoplankton in large lakes is a challenging task which requires the use of a wide variety of techniques to capture the range of spatial and temporal variations. The analysis of marker pigments may provide an adequate tool for phytoplankton surveys in large water bodies, thanks to automated analysis for processing numerous individual samples, and by achieving sufficient taxonomic resolution for ecological studies. Chlorophylls and carotenoids were analysed by HPLC in water column samples of Lake Tanganyika from 2002 through 2006, at two study sites, off Kigoma (north basin) and off Mpulungu (south basin). Using the CHEMTAX software for calculating contributions of the main algal groups to chlorophyll a, variations of phytoplankton composition and biomass were determined. We also investigated selected samples according to standard taxonomic techniques for elucidating the dominant species composition. Most of the phytoplankton biomass was located in the 0–40 m layer, with maxima at 0 or 20 m, and more rarely at 40 m. Deep chlorophyll maxima (DCM) and surface ‘blooms’ were occasionally observed. The phytoplankton assemblage was essentially dominated by chlorophytes and cyanobacteria, with diatoms developing mainly in the dry season. The dominant cyanobacteria were very small unicells (mostly Synechococcus), which were much more abundant in the southern basin, whereas green algae dominated on average at the northern site. A canonical correspondence analysis (CCA) including the main limnological variables, dissolved nutrients and zooplankton abundance was run to explore environment–phytoplankton relations. The CCA points to physical factors, site and season as key determinants of the phytoplankton assemblage, but also indicates a significant role, depending on the studied site, of calanoid copepods and of nauplii stages. Our data suggest that the factors allowing coexistence of several phytoplankton taxa in the pelagic zone of Lake Tanganyika are likely differential vertical distribution in the water column, which allows spatial partitioning of light and nutrients, and temporal variability (occurring at time scales preventing long-term dominance by a single taxon), along with effects of predation by grazers.     

Curcumin prevents Cr(VI)-induced renal oxidant damage by a mitochondrial pathway

We report the role of mitochondria in the protective effects of curcumin, a well-known direct and indirect antioxidant, against the renal oxidant damage induced by the hexavalent chromium [Cr(VI)] compound potassium dichromate (K₂Cr₂O₇) in rats. Curcumin was given daily by gavage using three different schemes: (1) complete treatment (100, 200, and 400 mg/kg bw 10 days before and 2 days after K₂Cr₂O₇ injection), (2) pretreatment (400 mg/kg bw for 10 days before K₂Cr₂O₇ injection), and (3) posttreatment (400 mg/kg bw 2 days after K₂Cr₂O₇ injection). Rats were sacrificed 48 h later after a single K₂Cr₂O₇ injection (15 mg/kg, sc) to evaluate renal and mitochondrial function and oxidant stress. Curcumin treatment (schemes 1 and 2) attenuated K₂Cr₂O₇-induced renal dysfunction, histological damage, oxidant stress, and the decrease in antioxidant enzyme activity both in kidney tissue and in mitochondria. Curcumin pretreatment attenuated K₂Cr₂O₇-induced mitochondrial dysfunction (alterations in oxygen consumption, ATP content, calcium retention, and mitochondrial membrane potential and decreased activity of complexes I, II, II-III, and V) but was unable to modify renal and mitochondrial Cr(VI) content or to chelate chromium. Curcumin posttreatment was unable to prevent K₂Cr₂O₇-induced renal dysfunction. In further experiments performed in curcumin (400 mg/kg)-pretreated rats it was found that this antioxidant accumulated in kidney and activated Nrf2 at the time when K₂Cr₂O₇ was injected, suggesting that both direct and indirect antioxidant effects are involved in the protective effects of curcumin. These findings suggest that the preservation of mitochondrial function plays a key role in the protective effects of curcumin pretreatment against K₂Cr₂O₇-induced renal oxidant damage.     

Helminth Antigens Enable CpG-Activated Dendritic Cells to Inhibit the Symptoms of Collagen-induced Arthritis through Foxp3+ Regulatory T Cells

Dendritic cells (DC) have the potential to control the outcome of autoimmunity by modulating the immune response. In this study, we tested the ability of Fasciola hepatica total extract (TE) to induce tolerogenic properties in CpG-ODN (CpG) maturated DC, to then evaluate the therapeutic potential of these cells to diminish the inflammatory response in collagen induced arthritis (CIA). DBA/1J mice were injected with TE plus CpG treated DC (T/C-DC) pulsed with bovine collagen II (CII) between two immunizations with CII and clinical scores CIA were determined. The levels of CII-specific IgG2 and IgG1 in sera, the histological analyses in the joints, the cytokine profile in the draining lymph node (DLN) cells and in the joints, and the number, and functionality of CD4+CD25+Foxp3+ T cells (Treg) were evaluated. Vaccination of mice with CII pulsed T/C-DC diminished the severity and incidence of CIA symptoms and the production of the inflammatory cytokine, while induced the production of anti-inflammatory cytokines. The therapeutic effect was mediated by Treg cells, since the adoptive transfer of CD4+CD25+ T cells, inhibited the inflammatory symptoms in CIA. The in vitro blockage of TGF-β in cultures of DLN cells plus CII pulsed T/C-DC inhibited the expansion of Treg cells. Vaccination with CII pulsed T/C-DC seems to be a very efficient approach to diminish exacerbated immune response in CIA, by inducing the development of Treg cells, and it is therefore an interesting candidate for a cell-based therapy for rheumatoid arthritis (RA).     

Mangrove Habitat Use by Juvenile Reef Fish: Meta-Analysis Reveals that Tidal Regime Matters More than Biogeographic Region

Identification of critical life-stage habitats is key to successful conservation efforts. Juveniles of some species show great flexibility in habitat use while other species rely heavily on a restricted number of juvenile habitats for protection and food. Considering the rapid degradation of coastal marine habitats worldwide, it is important to evaluate which species are more susceptible to loss of juvenile nursery habitats and how this differs across large biogeographic regions. Here we used a meta-analysis approach to investigate habitat use by juvenile reef fish species in tropical coastal ecosystems across the globe. Densities of juvenile fish species were compared among mangrove, seagrass and coral reef habitats. In the Caribbean, the majority of species showed significantly higher juvenile densities in mangroves as compared to seagrass beds and coral reefs, while for the Indo-Pacific region seagrass beds harbored the highest overall densities. Further analysis indicated that differences in tidal amplitude, irrespective of biogeographic region, appeared to be the major driver for this phenomenon. In addition, juvenile reef fish use of mangroves increased with increasing water salinity. In the Caribbean, species of specific families (e.g. Lutjanidae, Haemulidae) showed a higher reliance on mangroves or seagrass beds as juvenile habitats than other species, whereas in the Indo-Pacific family-specific trends of juvenile habitat utilization were less apparent. The findings of this study highlight the importance of incorporating region-specific tidal inundation regimes into marine spatial conservation planning and ecosystem based management. Furthermore, the significant role of water salinity and tidal access as drivers of mangrove fish habitat use implies that changes in seawater level and rainfall due to climate change may have important effects on how juvenile reef fish use nearshore seascapes in the future.     

Lipidomic Assessment of Plasma and Placenta of Women with Early-Onset Preeclampsia

Introduction

Adipose tissue is responsible for triggering chronic systemic inflammatory response and these changes may be involved in the pathophysiology of preeclampsia.

Objective

To characterize the lipid profile in the placenta and plasma of patients with preeclampsia.

Methodology

Samples were collected from placenta and plasma of 10 pregnant women with preeclampsia and 10 controls. Lipids were extracted using the Bligh–Dyer protocol and were analysed by MALDI TOF-TOF mass spectrometry.

Results

Approximately 200 lipid signals were quantified. The most prevalent lipid present in plasma of patients with preeclampsia was the main class Glycerophosphoserines-GP03 (PS) representing 52.30% of the total lipid composition, followed by the main classes Glycerophosphoethanolamines-GP02 (PEt), Glycerophosphocholines-GP01 (PC) and Flavanoids-PK12 (FLV), with 24.03%, 9.47% and 8.39% respectively. When compared to the control group, plasma samples of patients with preeclampsia showed an increase of PS (p<0.0001), PC (p<0.0001) and FLV (p<0.0001). Placental analysis of patients with preeclampsia, revealed the PS as the most prevalent lipid representing 56.28%, followed by the main class Macrolides/polyketides-PK04 with 32.77%, both with increased levels when compared with patients control group, PS (p<0.0001) and PK04 (p<0.0001).

Conclusion

Lipids found in placenta and plasma from patients with preeclampsia differ from those of pregnant women in the control group. Further studies are needed to clarify if these changes are specific and a cause or consequence of preeclampsia.     

Mesenchymal stromal cells alone or expressing interferon-β suppress pancreatic tumors in vivo,an effect countered by anti-inflammatory treatment

Background aimsBecause of the inflammatory nature and extensive stromal compartment in pancreatic tumors, we investigated the role of mesenchymal stromal cells (MSC) to engraft selectively in pancreatic carcinomas and serve as anti-tumor drug delivery vehicles to control pancreatic cancer progression.MethodsHuman pancreatic carcinoma cells, PANC-1, expressing renilla luciferase were orthotopically implanted into SCID mice and allowed to develop for 10 days. Firefly luciferase-transduced MSC or MSC expressing interferon (IFN)-β were then injected intraperitoneally weekly for 3 weeks. Mice were monitored by bioluminescent imaging for expression of renilla (PANC-1) and firefly (MSC) luciferase.ResultsMSC selectively homed to sites of primary and metastatic pancreatic tumors and inhibited tumor growth (P = 0.032). The production of IFN-β within the tumor site by MSC–IFN-β further suppressed tumor growth (P = 0.0000083). Prior studies indicated that MSC home to sites of inflammation; therefore, we sought to alter the tumor microenvironment through treatment with a potent anti-inflammatory agent. After treatment, inflammation-associated mediators were effectively down-regulated, including NFκB, vascular endothelial growth factor (VEGF) and interleukin (IL)-6 as well as chemokines involved in MSC migration (CCL3 and CCL25). Treatment with the anti-inflammatory agent CDDO-Me before and after MSC–IFN-β injections resulted in reduction of MSC in the tumors and reversed the positive effect of tumor inhibition by MSC–IFN-β alone (P = 0.041).ConclusionsThese results suggest that MSC exhibit innate anti-tumor effects against PANC-1 cells and can serve as delivery vehicles for IFN-β for the treatment of pancreatic cancer. However, these beneficial effects may be lost in therapies combining MSC with anti-inflammatory agents.     

Osteoporosis,the risk of vertebral fracture,and periodontal disease in an elderly group in Mexico City

doi: 10.1111/j.1741‐2358.2009.00342.x
Osteoporosis, the risk of vertebral fracture, and periodontal disease in an elderly group in Mexico City Objectives: The aims of this study were to identify the possible association of osteoporosis, fracture risk and periodontitis, and consider the role of pharmacological treatment of osteoporosis and the periodontal condition. Methods: Patients aged 60 and older from the Mexican National Medical Science and Nutrition Institute Salvador Zubirán participated in the study. DXA was used to assess osteoporosis and risk of vertebral fracture. A modified version of the extent and severity index (ESI) was applied to evaluate periodontitis (cut‐off point for attachment loss ≥ 4 mm) and all teeth were examined. Results: One hundred and sixty‐six patients were examined, 88.6% were females, 47.0% had osteoporosis and 38.6% showed a high risk of fracture. The modified ESI was 5.13 mm (SD 1.4), 57.8% (SD 29.7). The model for periodontitis severity showed an association with oral hygiene (OR = 1.85) and use of osteoporosis medication (OR = 0.43). The model for the extent of periodontitis identified an association with smoking (OR = 2.37), osteoporosis (OR = 1.82) and osteoporosis medication (OR = 0.36). The model for tooth loss detected an association with fracture risk (OR = 3.02) and osteoporosis medication (OR = 0.33). Conclusion: Periodontitis extent was associated with osteoporosis, and tooth loss with fracture risk.     

Endosperm culture: a facile and efficient biotechnological tool to generate passion fruit (Passiflora cincinnata Mast.) triploid plants

Plant Cell, Tissue and Organ Culture (PCTOC) - Triploid plants represent an important resource for the breeding of fruit and ornamental plants. Here, we report a facile and robust system for...     

Effects of 7-day intake of hydrogen-rich water on physical performance of trained and untrained subjects

Hydrogen-rich water (HRW) is used as a supplement to improve performance and reduce fatigue in athletes. However, the potentially beneficial effects of HRW intake could be mediated by the training status of athletes. The purpose of the study was to analyse the ergogenic effect of intake of HRW for one week on aerobic and anaerobic performance, both in trained and untrained individuals. Thirty-seven volunteers participated in the study and were divided into two experimental groups: trained cyclists and untrained subjects. A double-blind crossover design was performed in which all subjects took a placebo (PW) and nano-bubble HRW (pH: 7.5; hydrogen concentration: 1.9 ppm; oxidation-reduction potential (ORP): -600 mV). At the end of 7-day intake, performance was assessed by an incremental VO₂max test and by a maximum anaerobic test. After HRW intake, only trained cyclists improved their performance in the anaerobic test with an increase in peak power (from 766.2 ± 125.6 to 826.5 ± 143.4 W; d = .51) and mean power (from 350.0 ± 53.5 to 380.2 ± 71.3 W; d = .51), and a decrease in the fatigue index (from 77.6 ± 5.8 to 75.1 ± 5.9%; d = .45). The findings demonstrate that the ergogenic effect of HRW is mediated by the training status, and that 7-day intake of HRW would be an effective strategy for improving anaerobic performance in trained cyclists.