Phytoplankton and chemico-physical parameters of the Scardovari Lagoon (Po Delta,North Adriatic Sea) during 1991 and 1992

Abstract

During research directed towards the employment of the biological resources of the North Adriatic lagoons, from January 1991 to December 1992, in both tidal phases, a survey was carried out on the phytoplankton and the chemico-physical parameters of the Scardovari lagoon. Data analyses allowed two different areas to be distinguished: one inner, which was generally characterized by high phytoplanktonic densities (St. 3–4), the other outer, which was more influced by marine load (St. 1–2). Photosynthetic picoplankton was dominant in terms of cell number in most samples. Phytoplanktonic fraction >2 μm was represented mainly by diatoms, which showed the higher species number. During the sample observation, some dinoflagellates, considered toxic or potentially toxic, were found. Their presence was important because of their effect on the bivalve mollusc cultures.     

Isolated respiring heart mitochondria release reactive oxygen species in states 4 and 3

Isolated mitochondria respiring on physiological substrates, both in state 4 and 3, are reported to be or not to be a source of reactive oxygen species (ROS). The cause of these discrepancies has been investigated. As protein concentration was raised in in vitro assays at 37°C, the rate of H₂O₂ release by rat heart mitochondria supplemented with pyruvate/malate or with succinate (plus rotenone) was shown to increase (0.03–0.15?mg?protein/ml), to decrease (0.2–0.5?mg?protein/ml) and to be negligible (over 0.5?mg?protein/ml). The inhibition of mitochondrial respiration (with rotenone or antimycin A) or the increase in the oxygen concentration dissolved in the assay medium allowed an enhancement of ROS production rate throughout the studied range of protein concentrations. In mitochondria respiring in state 3 on pyruvate/malate or on succinate (plus rotenone), ROS release vanished for protein concentrations over 0.5 or 0.2?mg/ml, respectively. However, ROS production rates measured with low protein concentrations (below 0.1?mg/ml) or in oxygen-enriched media were similar or even slightly higher in the active respiratory state 3 than in the resting state 4 for both substrates. Consequently, these findings indicate that isolated mitochondria, respiring in vitro under conditions of forward electron transport, release ROS with Complex I- and II-linked substrates in the resting condition (state 4) and when energy demand is maximal (state 3), provided that there is sufficient oxygen dissolved in the medium.     

The immunogenicity to the first anti-TNF therapy determines the outcome of switching to a second anti-TNF therapy in spondyloarthritis patients

Introduction

Anti-TNF drugs have proven to be effective against spondyloarthritis (SpA), although 30% of patients fail to respond or experience adverse events leading to treatment discontinuation. In rheumatoid arthritis, the presence of anti-drug antibodies (ADA) against the first TNF inhibitor influences the outcome after switching. Our aim was to assess whether the response to a second anti-TNF drug is related to the previous development of ADA to the first anti-TNF drug SpA patients.

Methods

Forty-two SpA patients began a second anti-TNF drug after failing to respond to the first anti-TNF therapy. Clinical activity was assessed by the Ankylosing Spondylitis Disease Activity Score (ASDAS) at baseline (at the beginning of the first and second anti-TNF therapy) and at 6 months after switching. The drug and ADA levels were measured by ELISA before each administration.

Results

All patients were treated with anti-TNF drugs and mainly due to inefficacy were switched to a second anti-TNF drug. Eleven of 42 (26.2%) developed ADA during the first biologic treatment. At baseline, no differences in ASDAS were found in patients with or without ADA to the first anti-TNF drug (3.52 ± 1.03 without ADA vs. 3.14 ± 0.95 with ADA, p = 0.399) and to the second anti-TNF drug (3.36 ± 0.94 without ADA vs. 3.09 ± 0.91 with ADA, p = 0.466). At 6 months after switching, patients with previous ADA had lower disease activity (1.62 ± 0.93 with ADA vs. 2.79 ± 1.01 without ADA, p = 0.002) and most patients without ADA had high disease activity state by the ASDAS (25 out of 31 (80.6%) without ADA vs. 3 out of 11 (27.3%) with ADA, p = 0.002).

Conclusions

In SpA the failure to respond to the first anti-TNF drug due to the presence of ADA predicts a better clinical response to a second anti-TNF drug.     

Phylogeny and morphology of Hirsutella tunicata sp. nov. (Ophiocordycipitaceae), a novel mite parasite from Peru

A new species of Hirsutella was isolated from unidentified mites on Petri plates inoculated with soil and root fragments collected from asparagus rhizosphere at Virú, Northern Peru. The fungus differs from other Hirsutella species by an envelope surrounding the conidium, conidia dimension and DNA sequences. In PDA cultures, the mycelium produced aerial hyphae with conidiogenous cells mainly at right angles, occasionally showing a secondary conidiophore. The solitary conidia are cymbiform, slightly apiculate, 5.0–6.0 × 3.0–4.0 μm. Phylogenetic analyses with partial rRNA and β-tubulin gene sequences confirmed the fungus as an Hirsutella (Ophiocordycipitaceae). Closest species shown by maximum likelihood and neighbor-joining trees were H. nodulosa and H. aphidis, from which the new species differs for conidium or conidiogenous cells dimensions, lack of synnemata and host type. A recombination event was also detected in the rRNA of the holotype strain, involving Ophiocordyceps sinensis as major parent and O. cochlidiicola as minor parent. A complement, inverted insertion was also found in its rRNA, involving part of the ITS2 and 5.8S regions, flanked by two short nucleotide arrays. Due to conidia dimension and phylogenetic position, the fungus is described as Hirsutella tunicata sp. nov. A review of mononematous Hirsutella species is provided.     

Maintenance of temporal synchrony between syrphid flies and floral resources despite differential phenological responses to climate

Variation in species’ responses to abiotic phenological cues under climate change may cause changes in temporal overlap among interacting taxa, with potential demographic consequences. Here, we examine associations between the abiotic environment and plant–pollinator phenological synchrony using a long‐term syrphid fly–flowering phenology dataset (1992–2011). Degree‐days above freezing, precipitation, and timing of snow melt were investigated as predictors of phenology. Syrphids generally emerge after flowering onset and end their activity before the end of flowering. Neither flowering nor syrphid phenology has changed significantly over our 20‐year record, consistent with a lack of directional change in climate variables over the same time frame. Instead we document interannual variability in the abiotic environment and phenology. Timing of snow melt was the best predictor of flowering onset and syrphid emergence. Snow melt and degree‐days were the best predictors of the end of flowering, whereas degree‐days and precipitation best predicted the end of the syrphid period. Flowering advanced at a faster rate than syrphids in response to both advancing snow melt and increasing temperature. Different rates of phenological advancements resulted in more days of temporal overlap between the flower–syrphid community in years of early snow melt because of extended activity periods. Phenological synchrony at the community level is therefore likely to be maintained for some time, even under advancing snow melt conditions that are evident over longer term records at our site. These results show that interacting taxa may respond to different phenological cues and to the same cues at different rates but still maintain phenological synchrony over a range of abiotic conditions. However, our results also indicate that some individual plant species may overlap with the syrphid community for fewer days under continued climate change. This highlights the role of interannual variation in these flower–syrphid interactions and shows that species‐level responses can differ from community‐level responses in nonintuitive ways.     

Monitoring of the saproxylic beetle Morimus asper (Sulzer, 1776) (Coleoptera: Cerambycidae) with freshly cut log piles

Quantitative information on population size, structure and dynamics are urgently needed for assessing species extinction risk and developing monitoring measures, especially for beetles belonging to the threatened guild of saproxylic organisms. Here freshly cut log piles (FCLP) were tested for the monitoring of the longhorn beetle Morimus asper (Sulzer, 1776) (Coleoptera: Cerambycidae). Novel mathematical models based on presence–absence or count data were compared with the most commonly used capture–recapture methods to investigate if less invasive and easier approaches may be suitable for large-scale monitoring of this species and other large saproxylic beetles. The use of FCLP as bait was reliable to detect the presence and abundance of M. asper, and capture events were not influenced by the phenomena of trap-happiness or trap-shyness. In order to obtain accurate presence–absence estimates of M. asper at a reasonable cost piles of at least 0.25 m³ are suggested. Models which take into account the abundance of the species without marking individuals were the best compromise between costs and accuracy of estimation. Therefore, a reliable assessment of the population size of M. asper, can be based on count data without marking individuals. Because FCLP attract adults of M. asper and other saproxylic beetles, they could act also as potential ecological traps if chipped and/or removed after the sampling season. Therefore, if FCLP are used in monitoring as a part of conservation programmes, the piles should be left until completely decayed.     

Evidence for multiple introductions of Phragmites australis to North America: detection of a new non-native haplotype

We found a new non-native haplotype of Phragmites australis in North America that provides convincing evidence for multiple introductions of this highly invasive reed from Europe. Prior to our detection of this new non-native haplotype, invasion of North America by this reed grass was thought to be limited to a single cp-DNA haplotype–haplotype M. However, we found two sites colonized by haplotype L1 in Quebec, Canada, a haplotype native to northern Europe, Great Britain and Romania. Because the invasion of North America by P. australis is ongoing, and because there is evidence for intra- and inter-specific hybridization and increased fecundity resulting from outcrossing, more attention should be paid to genetic differences and associated vigor of populations of introduced Phragmites across North America.     

Direct inhibition of hexokinase activity by metformin at least partially impairs glucose metabolism and tumor growth in experimental breast cancer

Emerging evidence suggests that metformin, a widely used anti-diabetic drug, may be useful in the prevention and treatment of different cancers. In the present study, we demonstrate that metformin directly inhibits the enzymatic function of hexokinase (HK) I and II in a cell line of triple-negative breast cancer (MDA-MB-231). The inhibition is selective for these isoforms, as documented by experiments with purified HK I and II as well as with cell lysates. Measurements of ¹⁸F-fluoro-deoxyglycose uptake document that it is dose- and time-dependent and powerful enough to virtually abolish glucose consumption despite unchanged availability of membrane glucose transporters. The profound energetic imbalance activates phosphorylation and is subsequently followed by cell death. More importantly, the “in vivo” relevance of this effect is confirmed by studies of orthotopic xenografts of MDA-MB-231 cells in athymic (nu/nu) mice. Administration of high drug doses after tumor development caused an evident tumor necrosis in a time as short as 48 h. On the other hand, 1 mo metformin treatment markedly reduced cancer glucose consumption and growth. Taken together, our results strongly suggest that HK inhibition contributes to metformin therapeutic and preventive potential in breast cancer.