The Effect of Size and Diet on Gonad Production by the Chilean Sea Urchin Loxechinus albus

Conadal production was studied in Loxechinus albus (Molina, 1782) maintained in cages suspended from a long-line in the Estero Castro, Chiloé for 3 mo during the austral summer. The sea urchins were fed either an artificial diet or a natural diet consisting of the macroalgae Macrocystis pyrifera and Ulva sp. Both diets were tested for four size ranges: 40–45, 50–55, 60–65 and 70–75 mm diameter. For all four size ranges, highest gonad production was with the artificial diet. Gonad production was greatest in the 40–45 mm individuals with an increase of about 1,400% and 750% in the wet weight of gonads in individuals fed the artificial and natural diet, respectively. With the three other size ranges, the increase was nearly 100% with the artificial diet and nearly 0% with the natural diet The gonad index showed similar patterns, being highest in the smallest individuals. Small individuals fed the artificial diet would provide the most cost effective aquaculture as production is best. It is not necessary to grow L. albus to the minimal legal size for fisheries (70-mm diameter) for cost effective gonad production.     

Genomic characterization of the first oral avian papillomavirus in a colony of breeding canaries (<Emphasis Type="Italic">Serinus canaria</Emphasis>)

Papillomaviruses are non-enveloped, DNA viruses that infect skin and mucosa of a wide variety of vertebrates, causing neoplasias or simply persisting asymptomatically. Avian papillomaviruses, with six fully sequenced genomes, are the second most studied group after mammalian papillomaviruses. In this study, we describe the first oral avian papillomavirus, detected in the tongue of a dead Yorkshire canary (Serinus canaria) and in oral swabs of the same bird and other two live canaries from an aviary in Madrid, Spain. Its genome is 8,071 bp and presents the canonical papillomavirus architecture with six early (E6, E7, E1, E9, E2, E4) and two late open reading frames (L1 and L2) and a long control region between L1 and E6. This new avian papillomavirus L1 gene shares a 64% pairwise identity with FcPV1 L1, so it has been classified as a new species (ScPV1) within the Ethapapillomavirus genus. Although the canary died after showing breathing problems, there is no evidence that the papillomavirus caused those symptoms so it could be part of the oral microbiota of the birds. Hence, future investigations are needed to evaluate the clinical relevance of the virus.     

The effect of urban refuse compost and different tractors tyres on soil physical properties, soil erosion and maize yield

Application of urban refuse compost to agricultural soil could help to solve municipalities' problems related to the increasing production of waste only if soil property improvement and environmental conservation can be demonstrated. The use of low-pressure tractor tyres is another proposal in modern agriculture for reducing soil compaction. This study thus aimed to detect the effects of both compost and low-pressure tractor tyres on soil loss, runoff, aggregate stability, bulk density, penetrometer resistance and maize (Zea mays L.) yield. A 3-year field experiment was carried out on a hilly (15% slope) clay loam soil in central Italy. Twelve plots (200 m² each) were monitored with tipping-pot devices for runoff and soil erosion measurement. Treatments were: compost addition (64 Mg ha⁻¹), mineral fertilisation, use of low-pressure tyres, use of traditional tyres, with three replicates, in a fully randomised block design. Compost was applied once at the beginning of the experiment. Runoff reduction due to compost ranged between 7 and 399 m³ ha⁻¹ during seasons, while soil erosion was reduced between 0.2 and 2.4 Mg ha⁻¹. Mean weight diameter (MWD) of stable aggregates, measured on wheel tracks, increased by 2.19 mm, then progressively decreased. Compost significantly increased bulk density by 0.08 Mg m⁻³ due to its inert fraction content. This effect was less evident in the second and third year, probably due to harrowing. Maize yields were slightly, but significantly, reduced in composted plots by 1.72 Mg ha⁻¹ in the third year. Low-pressure tyres significantly reduced soil loss in the third year by 1 Mg ha⁻¹. Furthermore, they did not significantly influence runoff volumes and soil structural stability. Low-pressure tyres or compost addition were singly able to prevent an increase in penetrometer resistance due to agricultural machinery traffic. Low-pressure tyres increased the maize yield during the 3 years and the difference (0.4 Mg ha⁻¹) became significant in the third year. In conclusion, results show the positive lasting effect of compost in ameliorating soil physical properties and reducing runoff and soil erosion. Low-pressure tyres appear justifiable both for the observed increase of grain production and reduction of soil compaction. This latter effect is, nevertheless, masked by compost addition which is also able to reduce penetrometer resistance. Further research is required to explain the causes of the slight inhibition of grain yield observed when compost was compared with mineral fertilisation.     

Management strategies for forage rape (Brassica napus L. cv Goliath): Impact on dry-matter yield,plant reserves,morphology and nutritive value

Limited information is available on the grazing management principles of forage rape (Brassica napus L.), particularly in relation to grazing height and intensity and the impact of these on dry-matter (DM) yield and nutritive value. A glasshouse study was undertaken to investigate the effect of three defoliation heights (plant height at harvest; DH: 40, 70 and 90 cm; L, M and H DH respectively) and three defoliation intensities (height at which plants were cut; DI: 5, 20 and 35 cm of residual height; H, M and L DI respectively) on forage rape (cv Goliath) yield and nutritive value at two harvests (harvest 1, H1 and harvest 2, H2), and the impact of nitrogen (N) and water soluble carbohydrate (WSC) reserves on regrowth. Increasing DH from L to H increased estimated total DM yield (H1 plus H2) from 0.5 to 4.6 t DM/ha but DI did not affect yield. Dry-matter yield was optimized at 90 cm DH, but greater nutritive value was achieved by harvesting at lower levels of DH. Despite high in vitro DM digestibility (IVDMD; 852–889 g/kg), harvesting at 90 cm DH could not meet the protein requirement of lactating dairy cows and harvesting at lower levels risks nitrate poisoning. Our results indicate the optimum DH may be between 70 and 90 cm DH, and 20 and 35 cm DI, which requires further studies.     

Seasonality in Saint Croix male lamb reproductive development in northern Mexico

The aim of this study was to determine the influence of the season of birth on the body weight, testicular size, testosterone concentrations, semen output and sexual behaviour in Saint Croix male lambs. Thirty‐three lambs were born in spring (n = 10), summer (Sum; n = 12) or autumn (n = 11). Body weight and the scrotal circumference were weekly recorded; semen was also weekly collected by electroejaculation; and sexual behaviour towards oestrous ewes was weekly evaluated. Data were recorded from 15 to 33 weeks of age. The reproductive development of Saint Croix male lambs differed according to the period in which they were born. More lambs born in spring than in summer and autumn achieved puberty during this study and were also more precocious in semen production and displayed sexual behaviour earlier. Lambs born in summer delayed their semen production; however, season‐related negative effects were less pronounced at the end of the study than in autumn born lambs born. In conclusion, despite the apparently low seasonality of the breed, Saint Croix male lambs showed in this study a seasonal pattern in their reproductive development at least until they achieve the puberty.     

Heavy Metal Contents and Distribution in Coastal Sediments of the Gulf of Trieste (Northern Adriatic Sea, Italy)

A set of ten heavy metals (Al, As, Cd, Cr, Cu, Hg, Ni, Pb, V, and Zn) was investigated in surface sediments (0–5 cm) collected in 21 sites of the Gulf of Trieste, Northern Adriatic Sea (Italy). The aim of this work was to obtain a preliminary assessment about the levels and spatial distribution of these selected elements. Ancillary parameters such as grain size, total organic carbon, and total nitrogen were also determined. The enrichment factor was calculated to discriminate if a natural condition or a status of anthropogenic contamination occurs. In addition, a set of sediment quality guidelines, mean effect low range and effect medium range quotients, was also applied in order to predict the probability of adverse biological effects on the benthic community.     

Receptor activation alters inner surface potential during phagocytosis

The surface potential of biological membranes varies according to their lipid composition. We devised genetically encoded probes to assess surface potential in intact cells. These probes revealed marked, localized alterations in the charge of the inner surface of the plasma membrane of macrophages during the course of phagocytosis. Hydrolysis of phosphoinositides and displacement of phosphatidylserine accounted for the change in surface potential at the phagosomal cup. Signaling molecules such as K-Ras, Rac1, and c-Src that are targeted to the membrane by electrostatic interactions were rapidly released from membrane subdomains where the surface charge was altered by lipid remodeling during phagocytosis.     

Beneficial properties of lactic acid bacteria isolated from a Rana catesbeiana hatchery

This work addresses the selection of potentially probiotic lactic acid bacteria (LAB) to be used in raniculture. Thus, strains belonging to the genera Pediococcus pentosaceus, Leuconostoc mesenteroides, Lactococcus lactis and Enterococcus faecium isolated from a Rana catesbeiana hatchery were evaluated for their inhibitory properties against RLS-associated pathogens ( Proteus vulgaris, Pseudomonas aeruginosa, Staphylococcus epidermidis ) and food-borne bacteria. Cell-free supernatants of LAB strains inhibited the growth of at least one of the pathogens by organic acids, but L. lactis CRL 1584 also produced a bacteriocin-like metabolite. The ability of LAB strains to produce H₂O₂ in MRS+TMB medium was also studied. Seventy-eight to ninety six per cent of the strains showed some level of H₂O₂ production. Moreover, different organic solvents were used to determine the hydrophobicity and Lewis acid/base characteristic of LAB strain surfaces. Most of the strains presented hydrophilic properties, but no acidic or basic surface characters. However, some strains isolated from the skin showed a high degree of hydrophobicity and basic components in the cell surface due to their adhesion to chloroform. These properties were not observed in LAB from balanced feed and freshwater. Taking into account general guidelines and the beneficial properties studied, five strains were selected as potential candidates to be included in a probiotic for raniculture.     

Induced spawning of hatchery-raised Brazilian catfish, cachara Pseudoplatystoma fasciatum (Linnaeus, 1766)

In the months of January 2001 and 2002, female cachara Pseudoplatystoma fasciatum were selected during their first and second gonadal maturation (2 years and 7 months old and 3 years and 7 months old, respectively) with an of oocyte diameter of 937.5 μm (82.5% with central nuclei and 17.5% with peripheral nuclei). Nine females in first maturation received two doses of carp pituitary extract (CPE), 0.5 mg/kg and 5.0 mg/kg; seven received two doses of human chorionic gonadotropin (hCG), 5 and 10 IU/g; five received doses of 0.5 CPE mg/kg and 5 hCG IU/g (CPE+hCG); and four received 0.9% saline (saline). Nine females from CPE and seven from hCG presented oocytes with the same diameter at the moment of oocyte release (100% with germinal vesicle breakdown and fertilization rate of 53.44±18.3 and 54.81±11.8%; larvae number of 165,330±94.1 and 158,570±20.6, respectively). The five females from CPE+hCG did not respond to the hormonal treatment. The four females from the saline group did not ovulate. In January 2002, 6 of 15 selected females that were going through the second reproductive cycle received CPE (five received hCG and four received saline), showing oocyte diameters similar to the ones in the first maturation. At stripping, CPE females had an oocyte diameter of 1062.5 μm (the hCG females had oocyte diameters ranging from 937.5 to 1125.0 μm; fertilization rates of 56.08±30.9 and 81.90±17.3%; 364,547±244 and 633,129±190, larvae, respectively). The fertilization rates and larvae number were higher in the second gonad maturation, both for CPE and hCG.