The carbon isotopic composition of individual plant leaf waxes (a proxy for C₃ vs. C₄ vegetation) in a marine sediment core collected from beneath the plume of Sahara-derived dust in northwest Africa ...reveals three periods during the past 192,000 years when the central Sahara/Sahel contained C₃ plants (likely trees), indicating substantially wetter conditions than at present. Our data suggest that variability in the strength of Atlantic meridional overturning circulation (AMOC) is a main control on vegetation distribution in central North Africa, and we note expansions of C₃ vegetation during the African Humid Period (early Holocene) and within Marine Isotope Stage (MIS) 3 (almost equal to50-45 ka) and MIS 5 (almost equal to120-110 ka). The wet periods within MIS 3 and 5 coincide with major human migration events out of sub-Saharan Africa. Our results thus suggest that changes in AMOC influenced North African climate and, at times, contributed to amenable conditions in the central Sahara/Sahel, allowing humans to cross this otherwise inhospitable region.
2-Acetylpyridine acetylhydrazone (H2AcMe), 2-benzoylpyridine acetylhydrazone (H2BzMe) and complexes Cu(H2AcMe)Cl2 (1) and Cu(H2BzMe)Cl2 (2) were assayed for their cytotoxicity against wild type p53 ...U87 and mutant p53 T98 glioma cells, and against MRC-5 fibroblast cells. Compounds 1 and 2 proved to be more active than the corresponding hydrazones against U87, but not against T98 cells. Compound 1 induced higher levels of ROS than H2AcMe in both glioma cell lines. H2AcMe and 1 induced lower levels of ROS in MRC5 than in U87 cells. Compound 2 induced lower levels of ROS in MRC5 than in T98 cells. The cytotoxic effect of 1 in U87 cells could be related to its ability to provoke the release of ROS, suggesting that the cytotoxicity of 1 might be somehow p53 dependent.
Sedimentary organic pollution in the urban reaches of the Thames estuary is changing from fossil fuel hydrocarbons to emerging synthetic chemicals. De-industrialisation of London was assessed in ...three cores from Chiswick (Ait/Eyot) mud island using pharmaceuticals, faecal sterols, hydrocarbons (TPH, PAH), Black Carbon (BC) and organotins (TBT). These ranked in the order; BC 7590-30219 mg/kg, mean 16,000 mg/kg > TPH 770–4301, mean 1316 mg/kg > Σ16PAH 6.93–107.64, mean 36.46 mg/kg > coprostanol 0.0091–0.42 mg/kg, mean of 0.146 mg/kg > pharmaceuticals 2.4–84.8 μg/kg, mean 25 μg/kg. Hydrocarbons co-varied down-profile revealing rise (1940s), peak (1950s -1960s) and fall (1980s) and an overall 3 to 25-fold decrease. In contrast, antibiotics, anti-inflammatory (ibuprofen, paracetamol) and hormone (17β-estradiol) increased 3 to 50-fold toward surface paralleling increasing use (1970s-2018). The anti-epileptics, carbamazepine and epoxcarbamazepine showed appreciable down-core mobility. Faecal sterols confirmed non-systematic incorporation of treated sewage. Comparison to UK sediment quality guidelines indicate exceedance of AL2 for PAH whereas TBT was below AL1.
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•Pharmaceuticals (antibiotics) are rapidly increasing in urban estuarine sediments•Fossil fuel pollution and antifouling organo‑tins have declined but still present•Polycyclic aromatic hydrocarbons are above sediment quality guidelines•Black carbon exerts a strong control over sedimentary pollution in London•Sewage deposition is variable and sourced from both treated and untreated faeces•Antiepileptics, carbamazepine and epoxycarbamazipine are mobile in sediment
The UN Sustainable Development Goals highlight the myriad of socio-economic and environmental challenges occurring as a result of anthropogenic chemical pollution. Urban sediments from informal ...settlements (slums) on the Nairobi, Ngong and Mathare Rivers (n = 25), were evaluated for sediment quality. Microtox bioassay identified 8 sites as toxic, 9 as moderately toxic and 8 as non-toxic. Slum sediments were characterised by high total organic carbon and Rock-Eval pyrolysis revealed bound carbon from a mix of raw sewage and domestic refuse. Sediments from Kiambio, Kibera, Mathare and Kawangware slums contained high coprostanol at 55–298 μg/g and epicoprostanol at 3.2–21.7 μg/g confirming appreciable incorporation of untreated human faeces. Hormones, antianalgeiscs, antiinflamatories, antiepileptics and antibiotics most affected Mathare > Kiambio > Kibera > Mukuru > Kawangware slums. Carbamazepine, ibuprofen, diclofenac and acetaminophen concentrations are amongst the highest reported in Kenyan river sediments and were positively correlated with faecal steroids (sewage). Common persistent organic pollutants, such as organochlorine insecticides ΣDDT 1–59 μg/kg, mean 21.2 μg/kg, Σ16PAH 182–2218 μg/kg, mean 822 μg/kg and Σ30 PCB 3.1–157.1 μg/kg, mean of 21.4 μg/kg were between probable effect likely and unlikely sediment quality guidelines (SQG). PAH source ratios and parent to alkyl-PAH distribution suggested vehicle exhaust, power stations (heavy oil), kerosene (cooking oil) and other pollution sources. Trace metal concentrations As, Cd, Cr, Hg and Ni were below SQG whereas Pb exceeded the SQG. This multi-contaminant characterisation of sediment quality in Nairobi supports the development and implementation of policies to improve urban infrastructure to protect ecological and human health. It demonstrates the need for environmental geochemists to engage in the science-policy interface associated with both global and national development frameworks, with particular reference to the Sustainable Development Goals, New Urban Agenda, and Kenya’s Vision 2030.
•Urban slum river sediments of Nairobi are polluted with a mix of raw sewage and domestic refuse that presents a risk to human and ecological health.•Emerging pharmaceutical contamination (hormones, antibiotics antiinflamatories) are widespread.•PAH, PCB, DDT pollutants are ubiquitous but are between effect likely and unlikely sediment quality guidelines.•Nairobi slum sediments are toxic and contain a cocktail of organic contaminants but are low in most trace metals.
The antimicrobial activity of four labdane-type diterpenes isolated from the oleoresin of Copaifera langsdorffii as well as of two commercially available diterpenes (sclareol and manool) was ...investigated against a representative panel of microorganisms responsible for periodontitis. Among all the evaluated compounds, (-)-copalic acid (CA) was the most active, displaying a very promising MIC value (3.1 µg mL-1; 10.2 µM) against the key pathogen (Porphyromonas gingivalis) involved in this infectious disease. Moreover, CA did not exhibit cytotoxicity when tested in human fibroblasts. Time-kill curve assays performed with CA against P. gingivalis revealed that this compound only inhibited the growth of the inoculums in the first 12 h (bacteriostatic effect). However, its bactericidal effect was clearly noted thereafter (between 12 and 24 h). It was also possible to verify an additive effect when CA and chlorhexidine dihydrochloride (CHD, positive control) were associated at their MBC values. The time curve profile resulting from this combination showed that this association needed only six hours for the bactericidal effect to be noted. In summary, CA has shown to be an important metabolite for the control of periodontal diseases. Moreover, the use of standardized extracts based on copaiba oleoresin with high CA contents can be an important strategy in the development of novel oral care products.
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•n-alkane and brGDGT analysed to assess terrestrial C input in the Conwy Estuary.•Biomarkers in sediments showed a higher terrestrial influence compared to marine OC.•Molecular and ...bulk proxies compromised due to mixed source of compounds.•Similar concentration and fractional distribution of brGDGT in three UK estuaries.
Owing to their restricted riverine flow and greater numbers, small estuaries (annual discharge < 2000 m3 s−1) are important sites of organic carbon (OC) storage in sediments. The Conwy Estuary is an exemplar small rural-agricultural catchment which delivers a diverse pool of terrestrial OC to the Irish Sea. Thirty-nine surface sediments, covering a distance of 10.5 km, were taken transversal as well as longitudinal to the estuary to examine local and distant catchment inputs. Biomarkers (branched Glycerol Dialkyl Glycerol Tetraethers - brGDGTs, n-alkanes) and molecular and bulk proxies (BIT, Paq, TAR, δ13C, C/N), showed sediments were dominated by terrestrial inputs, with only sediments of the three most seaward sites showing stronger physical and geochemical characteristics of a marine influence (e.g., sandier sediments and lower BIT). Biomarker concentrations in the Conwy were comparable to the more urbanised Thames and the Clyde estuaries. The three estuaries showed similar fractional abundance of the brGDGTs, recording an inverse trend between the hexamethylated and the tetramethylated brGDGTs, and showing the pentamethylated brGDGTs as the dominant group. A systematic decrease in terrestrial biomarkers from bank to the main channel confirmed either a strong localised erosion/runoff process or a decrease in water velocity leading to a higher deposition.
Over the last four decades of palaeoclimate research, significant emphasis has been placed on the Last Glacial Maximum (LGM) spanning 26.5–19 thousand years ago (ka), a period that saw significant ...(∼125 m) sea-level reductions and major ice caps adorning large parts of the Northern Hemisphere. Here, we present evidence for another major glacial period spanning 71–59 ka (Marine Isotope Stage 4: MIS4) from a well-dated marine sequence offshore South Australia. The astronomically-tuned chronology of this deep-sea core is confirmed using single-grain optically stimulated luminescence dating (OSL), providing confidence in our high-resolution age model. Our approach to the study of our MD03-2607 core has been to employ many different proxies. These are: δ18O of both planktic and benthic foraminifera for stratigraphic purposes, faunal counts of planktonic foraminifera to reconstruct the position of oceanic fronts and currents, alkenone palaeothermometry, XRF core scanning to determine the presence of aeolian dust, and εNd isotope to identify fluvial discharge over the core site. We compare our new proxy findings with other archives for mainland Australia and Tasmania.
Our multi-proxy palaeoclimate reconstructions are consistent with other marine, terrestrial and cryosphere archives across the Southern Hemisphere and suggest, for the first time, that MIS 4 was almost as dramatic as the LGM. During MIS4, global sea-level was reduced by ∼100 m, glaciers across Australasia were more significant compared to the LGM, and sea-surface temperatures were much reduced. These glacial conditions uniformly peaked around 65 ka. Global comparisons show major glacial conditions and vegetation shifts elsewhere during MIS4, but many are poorly dated. The significant environmental changes taking place during this glacial period were paralleled by waves of human dispersal across Eurasia and the earliest evidence of human occupation in northern Australia at 65 ka.
•MIS4 was a major glacial period between 71 and 59 ka in the Southern Hemisphere.•Glacial conditions peaked at 65 ka, sea level dropped ∼100 m and SST dropped ∼5 °C.•Glaciers In New Zealand, Australia and Papua New Guinea were more pronounced at MIS4.•Multiproxy data confirm significant oceanic frontal changes offshore South Australia.•The deuterium excess change implies higher moisture reaching Antarctica during MIS4.
Changes in the strength of Atlantic meridional overturning circulation (AMOC) are known to have profound impacts on global climate. Coupled modelling studies have suggested that, on annual to ...multi-decadal time scales, a slowdown of AMOC causes a deepening of the thermocline in the tropical Atlantic. However, this process has been poorly constrained by sedimentary geochemical records. Here, we reconstruct surface (U
K'
37 Index) and thermocline (TEX
H
86) water temperatures from the Guinea Plateau Margin (Eastern tropical Atlantic) over the last two glacial
–interglacial cycles (~
192 kyr). These paleotemperature records show that periods of reduced AMOC, as indicated by the δ
13
C benthic foraminiferal record from the same core, coincide with a reduction in the near-surface vertical temperature gradient, demonstrating for the first time that AMOC-induced tropical Atlantic thermocline adjustment exists on longer, millennial time scales. Modelling results support the interpretation of the geochemical records and show that thermocline adjustment is particularly pronounced in the eastern tropical Atlantic. Thus, variations in AMOC strength appear to be an important driver of the thermocline structure in the tropical Atlantic from annual to multi-millennial time scales.
► Offshore NW Africa, the TEX
H
86 temperature proxy reflects thermocline temperatures. ► U
k'
37 SST and TEX
H
86 are used to examine ΔT, the SST-thermocline difference. ► ΔT, supported by a modelling experiment, reflects AMOC strength. ► Reconstructing ΔT allows reconstruction of past AMOC variations.
It has been reported that 58% of individuals with chronic kidney disease (CKD) have moderate to advanced periodontitis due to alterations of pH and biochemical composition in the saliva. In fact, the ...composition of this important biofluid may be modulated by systemic disorders. Here we investigate the micro-reflectance Fourier-transform infrared spectroscopy (FTIR) spectra of saliva that CKD patients submitted to periodontal treatment, aiming to identify spectral biomarkers of kidney disease evolution and the effectiveness of periodontal treatment, proposing possible biomarkers of disease evolution. Saliva from 24 CKD patients-stage-5 men, 29 to 64 years old-was evaluated in (i) patients starting periodontal treatment; (ii) patients 30 days after periodontal treatment; and (iii) patients 90 days after periodontal treatment. Our findings indicated that there are statistically relevant changes among the groups after 30 and 90 days of periodontal treatment, when considering the overall spectra in the fingerprint region (800-1800cm
). The key bands presenting good prediction power (area under the receiver operating characteristic curve >0.70) were related to poly (ADP-ribose) polymerase (PARP) conjugated to DNA at 883, 1031, and 1060cm
(carbohydrates at 1043 and 1049cm
) and triglycerides (1461cm
). Interestingly when analyzing the derivative spectra in the secondary structure region (1590-1700cm
), we detected over-expression of the
-sheet class of secondary structures in 90 days of periodontal treatment, possibly related to over-expression of human B-defensins. Conformational changes in ribose sugar in this region corroborate the interpretation concerning PARP detection. To our knowledge, PARP was detected for the first time in saliva samples of stage-5 CKD patients by FTIR. All observed changes were correctly interpreted in terms of intensive apoptosis and dyslipidemia due to kidney disease progression. Biomarkers due to CKD predominate in saliva, and the relative improvement in the periodontal state did not cause remarkable changes in the spectra of saliva.
Peptic ulcer episodes cause damage to the stomach and intestine, with inflammatory cell infiltration and oxidative stress as the main players. In this study, we investigated the potential of ...anthocyanidin malvidin for preventive and curative peptic ulcer treatment. The anthocyanidin effects were examined in gastric ulcer mouse models induced by ethanol, non-steroidal anti-inflammatory drugs (NSAIDs), ischemia-reperfusion (IR), acetic acid and duodenal ulcer induced by polypharmacy. Expression levels of oxidative and inflammatory genes were measured to investigate the mechanism of anthocyanin activity. At a dose of 5 mg·kg−1, Malvidin prevented gastric ulcer induction by ethanol, NSAID and repaired the tissue after 6 days of IR. Moreover, the anthocyanidin accelerated the healing of acetic acid-induced ulcer, increased the gene expression of EGF and COX-1, and downregulated MMP-9. Anthocyanin treatment mitigated the effect of polypharmacy on inflammation and oxidative stress observed in the intestine. Additionally, the compound downregulated cytokine expression and TLR4 and upregulated HMOX-1 and IL-10, exhibiting protective activity in the mouse gut. Malvidin thus prevented gastric and duodenal ulcers due to prominent anti-inflammatory and antioxidative effects on the gastrointestinal tract that were related to gene expression modulation and an increase in endogenous defense mechanisms.
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