Length–weight relationships of eight fish species from Guyana coastal drainages,Amapá, Brazil

The present study provides the length–weight relationships (LWR) for eight fish species in 19 streams from the Pedreira River basin, a small tributary of the Guyana coastal drainages from Amapá State, Brazil. Fishes were collected at two occasions, one in November 2016, the other in July 2018, using hand nets, with 0.5 mm of mesh size and 0.25 m² of mouth area, and trawl nets, with 0.5 mm of mesh size and 3 m long. Standard length and total weight were measured to determine the LWRs. The results show that the coefficient b varied between 2.798 and 3.380 and thus the values were within the expected range.     

Deep Crustal Communities of the Juan de Fuca Ridge Are Governed by Mineralogy

Volcanic ocean crust contains a global chemosynthetic microbial ecosystem that impacts ocean productivity, seawater chemistry and geochemical cycling. We examined the mineralogical effect on community structure in the aquifer ecosystem by using a four-year in situ colonization experiment with igneous minerals and glasses in Integrated Ocean Drilling Program Hole 1301A on the Juan de Fuca Ridge. Microbial community analysis and scanning electron microscopy revealed that olivine phases and iron-bearing minerals bore communities that were distinct from iron-poor phases. Communities were dominated by Archaeoglobaceae, Clostridia, Thermosipho, Desulforudis and OP1 lineages. Our results suggest that mineralogy determines microbial composition in the subseafloor aquifer ecosystem.     

CD8+ CD28- T regulatory lymphocytes inhibiting T cell proliferative and cytotoxic functions infiltrate human cancers

Tumor growth is allowed by its ability to escape immune system surveillance. An important role in determining tumor evasion from immune control might be played by tumor-infiltrating regulatory lymphocytes. This study was aimed at characterizing phenotype and function of CD8+ CD28- T regulatory cells infiltrating human cancer. Lymphocytes infiltrating primitive tumor lesion and/or satellite lymph node from a series of 42 human cancers were phenotypically studied and functionally analyzed by suppressor assays. The unprecedented observation was made that CD8+ CD28- T regulatory lymphocytes are almost constantly present and functional in human tumors, being able to inhibit both T cell proliferation and cytotoxicity. CD4+ CD25+ T regulatory lymphocytes associate with CD8+ CD28- T regulatory cells so that the immunosuppressive activity of tumor-infiltrating regulatory T cell subsets, altogether considered, may become predominant. The infiltration of regulatory T cells seems tumor related, being present in metastatic but not in metastasis-free satellite lymph nodes; it likely depends on both in situ generation (via cytokine production) and recruitment from the periphery (via chemokine secretion). Collectively, these results have pathogenic relevance and implication for immunotherapy of cancer.     

Recombinant Escherichia coli heat-labile enterotoxin B subunit humoral adjuvant effect depends on dose and administration route

Information on the use of Escherichia coli heat-labile enterotoxin B subunit (LTB) as a parenteral adjuvant is scarce. We evaluate the adjuvant effect of different concentrations of recombinant LTB (rLTB), as well as the influence of administration route (intramuscular and subcutaneous) on mice immune response. The use of 10 μg/dose of rLTB as adjuvant of an inactivated vaccine composed by Suid herpesvirus type 1 (SuHV-1), used to immunize mice intramuscularly, induced the highest average titers of anti-SuHV-1 antibodies (P < 0.05). The same vaccines used subcutaneously induced lower titers of antibodies. The lower the anti-rLTB humoral response determined by ELISA, the higher was its adjuvant activity. In the challenge experiment with SuHV-1, 56% (14/25) (P < 0.05) of the animals inoculated intramuscularly and 32% (8/25) inoculated subcutaneously survived, highlighting the influence of the concentration and the route of administration of rLTB on its performance as an adjuvant. Therefore, rLTB can significantly help in the induction of immunity against SuHV-1 in mice, especially if used intramuscularly in the concentration of 10 μg/dose, representing the best cost-benefit ratio.     

Carbonate Production by Benthic Communities on Shallow Coralgal Reefs of Abrolhos Bank,Brazil

The abundance of reef builders, non-builders and the calcium carbonate produced by communities established in Calcification Accretion Units (CAUs) were determined in three Abrolhos Bank shallow reefs during the period from 2012 to 2014. In addition, the seawater temperature, the irradiance, and the amount and composition of the sediments were determined. The inner and outer reef arcs were compared. CAUs located on the inner reef shelf were under the influence of terrigenous sediments. On the outer reefs, the sediments were composed primarily of marine biogenic carbonates. The mean carbonate production in shallow reefs of Abrolhos was 579 ± 98 g m^-2 y^-1. The builder community was dominated by crustose coralline algae, while the non-builder community was dominated by turf. A marine heat wave was detected during the summer of 2013–2014, and the number of consecutive days with a temperature above or below the summer mean was positively correlated with the turf cover increase. The mean carbonate production of the shallow reefs of Abrolhos Bank was greater than the estimated carbonate production measured for artificial structures on several other shallow reefs of the world. The calcimass was higher than the non-calcareous mass, suggesting that the Abrolhos reefs are still in a positive carbonate production balance. Given that marine heat waves produce an increase of turf cover on the shallow reefs of the Abrolhos, a decrease in the cover represented by reef builders and shifting carbonate production are expected in the near future.     

A rapid and cost-effective tool for managing habitats of the European Natura 2000 network: a case study in the Italian Alps

“Habitats” Directive 92/43/EEC is the pivotal European law for building a continental network of sites of community importance (SCIs) for nature conservation. Article 6 of such directive underlines the importance of biodiversity conservation through the realization of proper management plans. As a result, such plans are increasingly common. A management plan based on intensive field studies and monitoring activities requires time and financial resources, which are generally limited. The aim of this paper is to offer a rapid, cost-effective and scientifically based decision tool aimed to achieve GIS-based conservation strategies for habitats of EU interest within SCIs and, in general, within protected areas. As a case study, we considered species-rich Nardus grasslands (threatened by natural reconversion and intensive cattle grazing), and transition mires (threatened by pasturing and human disturbance) in a SCI in the Alps. Through a multi-criteria evaluation, we selected indicators and weights based upon our knowledge of the study area. As a result, we were able to: (a) quantify the level of existing threats, (b) suggest urgent conservation strategies, and (c) suggest future monitoring activities. Since the study area is representative of many protected areas in the Alps and the conservation topics under evaluation are frequent threats impacting habitats of EU interest, our decision model might be transferable to further areas given proper adaptation of weights to the intensity and the frequency of current threats.     

Genetic structure of <Emphasis Type="Italic">Leucojum aestivum</Emphasis> L. in the Po Valley (N-Italy) drives conservation management actions

The aim of this study was to assess the genetic variation and population structure of the geophyte Leucojum aestivum L. across the Po river valley (N-Italy), to inform conservation management actions with the selection of most suitable source populations for translocation purposes. L. aestivum is self-incompatible and occurs in S-Europe in fragmented wetlands and lowland forests along rivers. The species is particularly interesting for habitat restoration practices for its simplicity of ex situ conservation and cultivation. AFLP analyses were carried out on 16 fragmented populations, using four primer combinations. Correlations between genetic variation and demographic and ecological traits were tested. AFLP produced a total of 202 bands, 95.5% of which were polymorphic. Our results suggest that L. aestivum holds low to moderate levels of genetic diversity (mean Nei’s genetic diversity: H?=?0.125), mostly within-population. We found a gradient of two main biogeographic groups along western and eastern populations, while the STRUCTURE analysis found that the most likely number of clusters was K?=?3, shaping a partially consistent pattern. We explain the unusual negative correlation between genetic variation and population size with the high rate of vegetative reproduction. The levels of population differentiation suggest that fragmentation in L. aestivum populations has occurred, but that an active gene flow between fragmented populations still exists, maintained by flooding events or pollinators. Conservation management actions should improve habitat connectivity, especially for pollinators that vehicle upstream gene flow. Moreover, the west–east structure due to the lithological composition of the gravel and sand forming the alluvial plain of the Po river, should be considered when selecting source populations for translocation purposes.     

Impaired AMPA signaling and cytoskeletal alterations induce early synaptic dysfunction in a mouse model of Alzheimer's disease

Alzheimer's disease (AD) is a devastating neurodegenerative disorder that impairs memory and causes cognitive and psychiatric deficits. New evidences indicate that AD is conceptualized as a disease of synaptic failure, although the molecular and cellular mechanisms underlying these defects remain to be elucidated. Determining the timing and nature of the early synaptic deficits is critical for understanding the progression of the disease and for identifying effective targets for therapeutic intervention. Using single‐synapse functional and morphological analyses, we find that AMPA signaling, which mediates fast glutamatergic synaptic transmission in the central nervous system (CNS), is compromised early in the disease course in an AD mouse model. The decline in AMPA signaling is associated with changes in actin cytoskeleton integrity, which alters the number and the structure of dendritic spines. AMPA dysfunction and spine alteration correlate with the presence of soluble but not insoluble Aβ and tau species. In particular, we demonstrate that these synaptic impairments can be mitigated by Aβ immunotherapy. Together, our data suggest that alterations in AMPA signaling and cytoskeletal processes occur early in AD. Most important, these deficits are prevented by Aβ immunotherapy, suggesting that existing therapies, if administered earlier, could confer functional benefits.     

Responses of entomopathogenic fungi to the mutagen 4-nitroquinoline 1-oxide

Survival of entomopathogenic fungi under solar ultraviolet (UV) radiation is paramount to the success of biological control of insect pests and disease vectors. The mutagenic compound 4-nitroquinoline 1-oxide (4-NQO) is often used to mimic the biological effects of UV radiation on organisms. Therefore, we asked whether tolerance to 4-NQO could predict tolerance to UV radiation in thirty isolates of entomopathogenic fungi and one isolate of a xerophilic fungus. A dendrogram obtained from cluster analyses based on the 50 and 90 % inhibitory concentrations (IC₅₀ and IC₉₀, respectively) divided the fungal isolates into six clusters numbered consecutively based on their tolerance to 4-NQO. Cluster 6 contained species with highest tolerance to 4-NQO (IC₅₀ > 4.7 μM), including Mariannaea pruinosa, Lecanicillium aphanocladii, and Torrubiella homopterorum. Cluster 1 contained species least tolerant to 4-NQO (IC₅₀ < 0.2 μM), such as Metarhizium acridum (ARSEF 324), Tolypocladium geodes, and Metarhizium brunneum (ARSEF 7711). With few exceptions, the majority of Metarhizium species showed moderate to low tolerances (IC₅₀ between 0.4 and 0.9 μM) and were placed in cluster 2. Cluster 3 included species with moderate tolerance (IC₅₀ between 1.0 and 1.2 μM). In cluster 4 were species with moderate to high tolerance (IC₅₀ between 1.3 and 1.6 μM). Cluster 5 contained the species with high tolerance (IC₅₀ between 1.9 and 4.0 μM). The most UV tolerant isolate of M. acridum, ARSEF 324, was the least tolerant to 4-NQO. Also, L. aphanocladii, which is very susceptible to UV radiation, showed high tolerance to 4-NQO. Our results indicate that tolerance to 4-NQO does not correlate with tolerance to UV radiation. Therefore this chemical compound is not a predictor of UV tolerance in entomopathogenic fungi.