Evidence for dust grain growth in young circumstellar disks

Hundreds of circumstellar disks in the Orion nebula are being rapidly destroyed by the intense ultraviolet radiation produced by nearby bright stars. These young, million-year-old disks may not survive long enough to form planetary systems. Nevertheless, the first stage of planet formation-the growth of dust grains into larger particles-may have begun in these systems. Observational evidence for these large particles in Orion's disks is presented. A model of grain evolution in externally irradiated protoplanetary disks is developed and predicts rapid particle size evolution and sharp outer disk boundaries. We discuss implications for the formation rates of planetary systems.     

A Metataxonomic Approach Reveals Diversified Bacterial Communities in Antarctic Sponges

Marine sponges commonly host a repertoire of bacterial-associated organisms, which significantly contribute to their health and survival by producing several anti-predatory molecules. Many of these compounds are produced by sponge-associated bacteria and represent an incredible source of novel bioactive metabolites with biotechnological relevance. Although most investigations are focused on tropical and temperate species, to date, few studies have described the composition of microbiota hosted by Antarctic sponges and the secondary metabolites that they produce. The investigation was conducted on four sponges collected from two different sites in the framework of the XXXIV Italian National Antarctic Research Program (PNRA) in November–December 2018. Collected species were characterized as Mycale (Oxymycale) acerata, Haliclona (Rhizoniera) dancoi, Hemigellius pilosus and Microxina sarai by morphological analysis of spicules and amplification of four molecular markers. Metataxonomic analysis of these four Antarctic sponges revealed a considerable abundance of Amplicon Sequence Variants (ASVs) belonging to the phyla Proteobacteria, Bacteroidetes, Actinobacteria and Verrucomicrobia. In particular, M. (Oxymycale) acerata, displayed several genera of great interest, such as Endozoicomonas, Rubritalea, Ulvibacter, Fulvivirga and Colwellia. On the other hand, the sponges H. pilosus and H. (Rhizoniera) dancoi hosted bacteria belonging to the genera Pseudhongella, Roseobacter and Bdellovibrio, whereas M. sarai was the sole species showing some strains affiliated to the genus Polaribacter. Considering that most of the bacteria identified in the present study are known to produce valuable secondary metabolites, the four Antarctic sponges could be proposed as potential tools for the discovery of novel pharmacologically active compounds.     

Effect of Estradiol and Progesterone on Metabolic Biomarkers in Healthy Bitches

The aim of this study was to evaluate the possible association between hormonal changes that occur during oestrus and biomarkers related with glucose metabolism (glucose and insulin), lipid metabolism (lipidic profile and BChE) and adipokines (adiponectin and ghrelin) in healthy bitches. For this purpose, we measured these analytes in serum of bitches, at two times: before (T1) and after (T2) the LH peak that were established according to progesterone concentrations. Increased levels of total cholesterol (p < 0.01), high density lipoprotein cholesterol (HDL‐C) (p < 0.01), low density lipoprotein cholesterol (LDL‐C) (p < 0.01), adiponectin (p < 0.01) and ghrelin (p < 0.05) were observed at T2 in comparison with T1. No statistically significant changes were observed in serum glucose, insulin, homoeostasis model assessment for insulin sensitivity (HOMA), triglycerides and BChE. When all data of T1 and T2 were pooled, serum adiponectin showed positive correlation with progesterone (r = 0.353; p = 0.022) and HDL‐C (r = 0.307; p = 0.048), and negative with insulin (r = ?0.429; p = 0.005), HOMA (r = ?0.446; p = 0.003) and BChE (r = ?0.522; p < 0.001). Ghrelin showed negative correlation with estradiol (r = ?0.701; p = 0.004). BChE was negatively correlated with estradiol (r = ?0.441; p = 0.018) and glucose (r = ?0.343; p = 0.028), and positively with insulin (r = 0.460; p = 0.003) and HOMA (r = 0.505; p < 0.001). In conclusion, changes in metabolic biomarkers occur in bitches after LH peak, characterized by increased lipids (total cholesterol, HDL cholesterol and LDL cholesterol) without changes in BChE activity, and increased adiponectin and ghrelin concentrations, without significant changes in glucose and insulin.     

Fuel vertical structure affects fire sustainability and behaviour of prescribed burning in Spartium junceum shrublands

? Context

Prescribed burning is increasingly recommended to control encroaching shrublands in the Mediterranean area.

? Aims

The aims of this paper are to analyze the fuel structural characteristics of Spartium junceum and how they influence fire behaviour during prescribed burning.

? Methods

Two winter–spring prescribed burns were conducted in 2009 and 2011. Fuel load and structure of S. junceum shrubs were assessed using the Cube Method, and shrub 3-D models were built using the FIRE PARADOX FUEL MANAGER software. Allometric equations to estimate S. junceum fuel load were developed. During burning, thermocouples measured temperature variations, which were then analyzed relative to fuel characteristics.

? Results

Fuel load components and distribution were strictly related to shrub height; in tall shrubs, most of the fine fuel was more than 1.5 m aboveground. Due to fuel vertical discontinuity, not all shrubs were burned in the fires, but wind increased fire sustainment and fuel consumption. Maximum temperatures (over 800 °C) and residence times were positively related to fuel load.

? Conclusion

S. junceum tall shrublands represent high hazard formations due to their elevated fuel load, mostly in fine fuel fractions. Vertical discontinuity among fuel strata limits fire propagation in mild weather conditions. Winter–spring prescribed burning cannot eliminate S. junceum shrublands, but do create shrub cover discontinuity. As S. junceum has fire-adapted morphological traits, a single burn is insufficient to control it.     

Oestrous Synchronization,Ovarian Superovulation and Intraspecific Transfers From a Closed Breeding Colony of Inbred SLA Miniature Pigs

The inbred SLA miniature pig is a unique animal model developed for organ transplantation studies and pre‐clinical experimental purposes. Reported oestrous synchronization and superovulation treatments were examined in two SLA haplotypes (AA and DD) to allow collection of embryos for both practical embryo transfer and experimental technologies from a closed breeding colony. Pre‐puberal miniature pigs were poor responders to oestrous synchronization treatments, while post‐puberal sows were equivalent to commercial sows. Following superovulation, the ovulation number (corpora .hemorrhagica) was higher (p < 0.05) in the cycling sows when compared with non‐cycling sows. Ovulations were equivalent to commercial pre‐puberal gilts and non‐cycling sows (p > 0.05). No difference in ovulation number between haplotypes was observed, which differs from the previous report (DD>AA). Collection of zygotes for pronuclear injection was the highest in the non‐cycling post‐puberal miniature pig group (p < 0.05), although significantly lower when compared with the commercial pig treatment groups (p < 0.05). The incidence of cystic endometrial hyperplasia in our colony was equivalent to rates observed in commercial pigs. Pronuclear visualization following centrifugation was the highest in the non‐cycling miniature sow group and approximates to about 25% of ovulations and about half the rate observed in the commercial pigs (50%). Miniature pig embryos transferred between SLA haplotypes and transfer of DD embryos to commercial pigs resulted in live births at a higher efficiency than previously reported. This study demonstrates the feasibility of undertaking assisted reproductive technologies in a closed breeding colony of inbred SLA miniature pigs without compromise to the breeding programmes.     

A low-magnetic-field soft gamma repeater

Soft gamma repeaters (SGRs) and anomalous x-ray pulsars form a rapidly increasing group of x-ray sources exhibiting sporadic emission of short bursts. They are believed to be magnetars, that is, neutron stars powered by extreme magnetic fields, B ~ 10(14) to 10(15) gauss. We report on a soft gamma repeater with low magnetic field, SGR 0418+5729, recently detected after it emitted bursts similar to those of magnetars. X-ray observations show that its dipolar magnetic field cannot be greater than 7.5 × 10(12) gauss, well in the range of ordinary radio pulsars, implying that a high surface dipolar magnetic field is not necessarily required for magnetar-like activity. The magnetar population may thus include objects with a wider range of B-field strengths, ages, and evolutionary stages than observed so far.     

Characterization of antimicrobial resistant Salmonella enterica serovars Enteritidis and Typhimurium isolates from animal and food in Southern Italy

In the last two decades, the emergence and spread of antimicrobial-resistant pathogens, among them Salmonella, has become a serious health hazard worldwide, and specifically the high incidence of multidrug resistance has been encountered widely in many European countries. This study examines the antimicrobial supsceptibility of Salmonella enterica strains Typhimurium and Enteritidis isolated in Campania and Calabria region (Southern Italy) from animal and food of animal origin. The relationship of antibiotic resistance phenotype and the presence of some resistance genes has been also investigated. As espected, our results showes that resistance to ampicillin, chloramphenicol, streptomycin, sulphonamides and tetracycline is common, although resistance to other antibiotics (i.e.:nalidixic acid) and other resistance patterns occur. The genetic resistant patterns have been partially described for this food-borne pathogen but efforts are needed to realize the complete characterization of antimicrobial resistance genes.     

Cadmium,lead and metallothionein contents in cultivated mussels (Mytilus galloprovincialis) from the Gulf of Naples (Southern Italy)

The concentration of cadmium and lead ions was determined in digestive gland and mantle of mussels (Mytilus galloprovincialis) from five aquaculture stations located in the Gulf of Naples (Southern Italy, Tyrrhenian Sea). Metallothionein (MT) levels in the same tissues were also evaluated. This gulf represents a greatly urbanized area, characterized by an important commercial port and past industrial activities, terminated in the last decade of the 20th century. The results were compared with those obtained from mussels cultivated in a more pristine neighbouring area. Data demonstrate that the amount of both metals found in mussels harvested at the highly anthropogenic sites in the Gulf of Naples was comparable with that found in mussels from the more naturalistic site. The content of both cadmium and lead was not related with that of MT. Indeed, the amount of both metals in the digestive gland was greater than in the mantle, whereas the MT preferentially accumulated in the mantle. Possibly, the MT content in mantle was associated to the physiological function of the tissue, rather than heavy metals exposure.     

Ciona intestinalis as a Marine Model System to Study Some Key Developmental Genes Targeted by the Diatom-Derived Aldehyde Decadienal

The anti-proliferative effects of diatoms, described for the first time in copepods, have also been demonstrated in benthic invertebrates such as polychaetes, sea urchins and tunicates. In these organisms PUAs (polyunsaturated aldehydes) induce the disruption of gametogenesis, gamete functionality, fertilization, embryonic mitosis, and larval fitness and competence. These inhibitory effects are due to the PUAs, produced by diatoms in response to physical damage as occurs during copepod grazing. The cell targets of these compounds remain largely unknown. Here we identify some of the genes targeted by the diatom PUA 2-trans-4-trans-decadienal (DD) using the tunicate Ciona intestinalis. The tools, techniques and genomic resources available for Ciona, as well as the suitability of Ciona embryos for medium-to high-throughput strategies, are key to their employment as model organisms in different fields, including the investigation of toxic agents that could interfere with developmental processes. We demonstrate that DD can induce developmental aberrations in Ciona larvae in a dose-dependent manner. Moreover, through a preliminary analysis, DD is shown to affect the expression level of genes involved in stress response and developmental processes.     

The use of Kluyveromyces marxianus in the diet of Red‐Stirling tilapia (Oreochromis niloticus,Linnaeus) exposed to natural climatic variation: effects on growth performance,fatty acids,and protein deposition

The purpose of this study was to evaluate the use of single cell proteins (Kluyveromyces marxianus) as fishmeal substitutes for Oreochromis niloticus during long‐term feeding under natural climatic conditions. Juveniles (150) were divided into two groups: the control group, fed with conventional fish diet (T1); and the experimental group, fed with the alternative diet (T2). T1 animals had a higher final weight and per cent weight gain than T2 animals, which we mainly observed in winter and autumn. The lipid content ranged from 1.9% to 3.8% in liver and from 0.2% to 1% in white muscle for both groups. T2 animals had a higher protein concentration in the fillet and the lipid content in this tissue was not altered by diet. Liver and plasma protein content in both groups and the muscle content in T1 decreased during growth. Specific fatty acids (FAs) were selectively retained in fillet phospholipids (PLs), primarily as C22:6n3, which was found at high levels in the PLs of both groups during all seasons. Despite the differences observed, the percentage of polyunsaturated FAs in the fillet was similar throughout the experiment for both diets, reaching approximately 50% of the total FA in the PLs.