Sound features and vocal rhythms as a proxy for locating the spawning ground of Sciaena umbra in the wild

• 1. The brown meagre (Sciaena umbra) is a demersal sciaenid fish recognized as indicative of good environmental quality and is defined as an umbrella species for the ecological community of rocky coastal habitats. Sciaena umbra is classified as a Vulnerable fish species by the International Union for Conservation of Nature (IUCN) and knowledge on the distribution of its spawning habitats is essential for its conservation.
• 2. Passive acoustic monitoring (PAM) is a suitable tool to monitor S. umbra distribution because of the high consistency, over space and time, of the communication sounds that this species emits during the reproductive period, with irregular or regular rhythms, or with calls merging into a chorus.
• 3. During the summer of 2019, the presence of this species was investigated acoustically at 40 listening points distributed along the tidal inlets that connect the Venice lagoon with the open sea.
• 4. Longer sounds, comprising a higher number of faster repeated pulses, were found during the chorus and were used as a proxy of spawning activity; similar sound features have been recorded in different captive Sciaenids during spawning.
• 5. The three inlets were classified as more or less suitable for spawning on the basis of the vocal rhythms identified, demonstrating a clear preference along a north–south gradient and indicating higher spawning activity in the internal‐facing areas of the inlets, compared with the seaward‐facing areas. The chorus occurred in localized areas consistently throughout the breeding season, suggesting that spawning is concentrated in preferred areas.
• 6. For the first time a relationship between the sound features and vocal rhythms of fish has been highlighted by an in situ study. This validates the use of the chorus as a reliable natural indicator of S. umbra breeding sites, and in turn suggests a potential non‐invasive approach based on PAM for mapping the key reproductive areas of this vulnerable species in the Mediterranean Sea.

     

Dietary Beta-Glucans and Nucleotides Enhance Resistance of Red-Tail Black Shark (Epalzeorhynchos bicolor, fam. Cyprinidae) to Streptococcus iniae Infection

Two experiments were conducted to examine the effect of commercially available beta‐glucan (Macrogard) and nucleotide (Aquagen) on the resistance to Streptococcus iniae infections in vaccinated or nonvaccinated juvenile red‐tail black sharks (Epalzeorhynchos bicolor, RTB) (1.4 ± 0.4 g weight total (WT), 5.6 ± 0.5 cm total length (TL)). The immunostimulants were added to a control diet formulated without any yeast source following the recommended doses of 1 g/kg feed for the beta‐glucan and 2 g/kg feed for the nucleotide. Beginning 4 d after introduction into tanks, fish were fed the experimental diets for 24 d, at 3% body weight per day, divided into two feedings. At the end of this period, fish were challenged by an intracoelomic injection of S. iniae. In the first experiment, both vaccinated and nonvaccinated fish were fed one of the two immunostimulants. In the second experiment, only vaccinated fish were fed the immunostimulants. Fish were vaccinated a week after being introduced into the system and challenged by intracoelomic injection with 1.5 × 10⁵ S. iniae colony‐forming units /fish after three additional weeks; mortality was recorded for 2 wk after the bacterial challenge. In the first experiment, the mortality of both vaccinated and nonvaccinated fish fed beta‐glucan (23 ± 7% and 82 ± 1%, respectively) or nucleotide (28 ± 6% and 86 ± 5%, respectively) was significantly lower than the mortality of the control groups (35 ± 4% and 93 ± 5%, respectively), but there was no significant difference in mortality between fish fed beta‐glucan or nucleotide. In the second experiment, the mortality of vaccinated fish fed beta‐glucan (25 ± 7%) or nucleotide (43 ± 9%) was significantly lower than that of vaccinated fish fed the control diet (69 ± 7%). In both experiments, there was no significant difference in growth rate among fish fed immunostimulants or the control diet. The results of this investigation demonstrated the efficacy of beta‐glucans and nucleotides in increasing resistance to S. iniae in RTB sharks.     

Mammary carcinoma in a tiger (Panthera tigris): morphological and immunohistochemical study

The histologic and immunohistochemical features of a case of mammary gland carcinoma are described in a 14-yr-old female tiger (Panthera tigris). Immunoreactivity to estrogen receptor (ER), progesterone receptor (PR), tumoral protein 53 (p53), vascular endothelial growth factor (VEGF), human epidermal growth factor receptor 2 (HER-2), and cyclooxigenase-2 (COX-2) was investigated. Neoplastic cells were negative for ER, PR, and p53 but showed positivity for VEGF, HER-2, and COX-2, both in the primary and the metastatic lesions. Histopathologic findings and immunohistochemistry results suggested that the malignant behavior of the reported case could be comparable with some aggressive cat mammary carcinomas.     

Preliminary investigations of hydrogen peroxide treatment of selected ornamental fishes and efficacy against external bacteria and parasites in green swordtails

The objectives of these preliminary studies were to evaluate the use of hydrogen peroxide (H2O2) for the treatment of selected species of ornamental fishes and its efficacy in treating external bacteria and parasites. In the first part of the study, fish of five species (serpae tetra Hyphessobrycon eques (also known as Serpa tetra H. serpae), tiger barb Puntius tetrazona, blue gourami Trichogaster trichopterus, suckermouth catfish Hypostomus plecostomus, and green swordtail Xiphophorus hellerii) were exposed to H2O2 for 1 h at concentrations between 6 and 34 mg/L or for 24 h at concentrations between 1 and 6 mg/L. The results were species specific: green swordtails tolerated all of the treatments, serpae tetras and tiger barbs were sensitive only to the highest concentration, and mortalities of suckermouth catfish and blue gourami were recorded in every treatment. In the second part of the study, clinically healthy green swordtails and fish infested with external motile rod-shaped bacteria (i.e., Ichthyobodo spp., Trichodina spp., and Gyrodactylus spp.) were treated with several concentrations of H2O2. A single H2O2 treatment of 3.1 mg/L or more for 1 h effectively eliminated external bacteria, concentrations of 6.5 mg/L or more appeared to effectively kill Ichthyobodo spp., and none of the treatments tested was effective against Trichodina spp. or Gyrodactylus spp. These preliminary findings suggest that H2O2 is effective for treating certain external bacterial infections and flagellate infestations in some species of ornamental fish at the dosages tested. Other treatment regimens may need to be tested for effectiveness against Trichodina spp. and Dactylogyrus spp.     

Accumulation and erosion of Mars' south polar layered deposits

Mars' polar regions are covered with ice-rich layered deposits that potentially contain a record of climate variations. The sounding radar SHARAD on the Mars Reconnaissance Orbiter mapped detailed subsurface stratigraphy in the Promethei Lingula region of the south polar plateau, Planum Australe. Radar reflections interpreted as layers are correlated across adjacent orbits and are continuous for up to 150 kilometers along spacecraft orbital tracks. The reflectors are often separated into discrete reflector sequences, and strong echoes are seen as deep as 1 kilometer. In some cases, the sequences are dipping with respect to each other, suggesting an interdepositional period of erosion. In Australe Sulci, layers are exhumed, indicating recent erosion.     

Biomedical exploitation of chitin and chitosan via mechano-chemical disassembly, electrospinning, dissolution in imidazolium ionic liquids, and supercritical drying

Recently developed technology permits to optimize simultaneously surface area, porosity, density, rigidity and surface morphology of chitin-derived materials of biomedical interest. Safe and ecofriendly disassembly of chitin has superseded the dangerous acid hydrolysis and provides higher yields and scaling-up possibilities: the chitosan nanofibrils are finding applications in reinforced bone scaffolds and composite dressings for dermal wounds. Electrospun chitosan nanofibers, in the form of biocompatible thin mats and non-wovens, are being actively studied: composites of gelatin + chitosan + polyurethane have been proposed for cardiac valves and for nerve conduits; fibers are also manufactured from electrospun particles that self-assemble during subsequent freeze-drying. Ionic liquids (salts of alkylated imidazolium) are suitable as non-aqueous solvents that permit desirable reactions to occur for drug delivery purposes. Gel drying with supercritical CO(2) leads to structures most similar to the extracellular matrix, even when the chitosan is crosslinked, or in combination with metal oxides of interest in orthopedics.     

Resistance traits and AFLP characterization of diploid primitive tuber-bearing potatoes

Worldwide, a variety of pathogens negatively affect potato production, resulting in an estimated 22% annual yield reduction. Wild Solanum species represent a unique gene pool where all the traits necessary to improve the cultivated potato can be found. Therefore, breeding efforts for improved disease resistance and research aimed at characterizing wild germplasm have been extensively made. In this paper, sources of resistance to Phytophthora infestans, Erwinia carotovora subsp. carotovora, Fusarium solani and Globodera spp. have been investigated in several clones of two Solanum species originating from Central Mexico (S. bulbocastanum and S. cardiophyllum). Interestingly, we found sources of combined resistance to late blight and bacterial soft rot. This is an important finding considering that the development of resistant potato varieties has been hindered by the scarcity of resistant germplasm. In addition, we explored molecular differences within and between the two species generating AFLP fingerprints. By means of six primer pair combinations, we found 13 and 16 putative species-specific AFLP markers for S. bulbocastanum and S. cardiophyllum, respectively, and a bounty of markers useful for mapping, MAS, and cloning purposes. The phenotypic and molecular information associated to S. bulbocastanum and S. cardiophyllum for designing strategies of assisted selection are discussed.     

Retention of coumaric acid by soil and its colloidal components

In this study of the behavior of coumaric acid added to soil, the disappearance of the acid was found to be due to adsorption plus microbial degradation, and was influenced by the concentration and contact time. Adsorption experiments set up with soils varying widely in their chemical and physical properties, showed that the Freundlich isotherm fits the data quite well and that among the different soil factors, only the pH was closely and negatively correlated with coumaric acid adsorption. Approximately at pH > 7 no adsorption occurred, perhaps due to the repulsion between the negatively charged soil colloids and the dissociated acidic groups of coumaric acid. Adsorption experiments carried out with different adsorbents showed that the hydroxy-Fe compound was the most effective in retaining coumaric acid, followed by humic acid, illite, kaolinite and vermiculite, in this order.     

Fungi-to-bacteria ratio in soils of European Russia

The selective inhibition technique by specific antibiotics (streptomycin, cycloheximide) applied to substrate-induced respiration (SIR) measurement was used to test the relative contribution of fungi to bacteria (F/B ratio) to the overall microflora-induced activity in soils of European Russia. Investigated soils covered a wide climatic transect and different ecosystem types including managed vs. natural ecosystems. Before direct comparison among sites, the antibiotic inhibition technique was optimized for soil characteristics. Once the optimal concentration was set, the combined effect of the two antibiotics resulted in average 60% inhibition of SIR. The analyzed sites (in total 47) including various biomes (tundra, middle taiga, southern taiga, subtaiga, dark coniferous forests outside the boreal region, steppe, mountain forests and arable sites), were characterized by a wide range of soil pH_w (3.95–7.95), soil organic carbon (0.69–24.08%), soil microbial biomass carbon (149–5028 µg C g^?1 soil) and soil basal respiration (0.24–8.28 µg CO₂-C g^?1 soil h^?1). In all the analyzed sites, a predominance of fungal over bacteria activity was observed with F/B ratios always higher than one (4.9 on average). Natural sites were characterized by higher F/B ratios (on average 5.6) compared to agricultural ones (on average 3.5).     

Growth and mineral content of roots and shoots of maize seedlings in response to increasing water deficits induced by peg solutions

Abstract

The effects of polyethylene glycol (PEG) solutions of increasing osmotic potentials (ψπ=?0.44 and ‐0.88 MPa) on the growth of the seedlings and on the concentrations of Mn, Cu, Pb, Zn, Ni, Co, Mo, Cr, Cl, Fe, Ca, Mg, K, Na, P, and N were determined in the shoots and roots of maize (Zea mays L. cv. Summer II) grown in Hoagland's solution in a growth chamber. Water stress was imposed for three days with PEG 4000 on six‐day‐old seedlings. Despite a reduction in the leaf water potential (ψw), which decreased with increasing PEG concentrations, and despite an increase in the water saturation deficit (W.S.D.), the pressure potentials (ψp) were maintained in both treatments at levels quite similar to that in the control seedlings.

At ψπ=?0.44 MPa of the growth medium, both the length and dry weight of the shoots and roots significantly decreased, whereas at ψπ=?0.88 MPa only the root length continued to decrease with the consequence of an increase in the total mass production of the seedlings. At ψπ=?0.88 MPa, PEG was absorbed by the seedlings in significant amounts, although the roots were undamaged.

The effects of the imposed water stress on nutrient absorption and accumulation differed in the two treatments, depending on the plant tissue and nutrient; nevertheless, the element contents generally showed their lowest values at ψπ=?0.44 MPa, as consequence of the reduction in dry matter. The water stress experienced by the maize seedlings grown at ψπ=?0.88 MPa did not induce further decreases in either the macro‐ or micronutrients.