Growth and mortality of larval anchoveta Engraulis ringens,in northern Chile during winter and their relationship with coastal hydrographic conditions

Larval growth, age, growth effect and instantaneous mortality were estimated in anchoveta, Engraulis ringens, collected biweekly during the austral winter of 2014 in nearshore waters off Bay of Antofagasta (23°41′W–70°30′S), northern Chile. Through measuring standard length (SL) and sagitta microstructure analysis, it was estimated that the growth rate of E. ringens larvae decreased from June (0.85 mm day^?1) to August (0.50 mm day^?1). However, the water temperature was homogeneous during the sampling dates (14.6, 15.2, 14.4, and 14.6°C), suggesting that the decelerating larval growth was not linked to changes in sea temperature. Additionally, larvae with slow growth have larger otoliths compared with conspecifics with fast growth (growth effect). Larval mortality rates tended to decrease until the middle of July (0.18 per day) but increased to 0.25 per day in early August, which coincided with lower food availability (i.e., chlorophyll‐a, 2.7–5.6 mg m^?3) and a high occurrence of smaller larvae (1.58–11.5 mm). Partial least squares analysis indicates low covariance between the biological and oceanographic variables (PLS: 11.71%), suggesting that other factors, such as parental effects, may explain the abrupt decrease in the larval growth rates.     

Survey of the Bru1 gene for brown rust resistance in Brazilian local and basic sugarcane germplasm

Bru1 is currently the major gene conferring brown rust resistance in sugarcane, and diagnostic markers are available. A survey for the presence of this gene was conducted on 391 genotypes including Brazilian cultivars, clones and basic germplasm. The efficiency of these markers for identifying resistant cultivars and artificially inoculated basic germplasm was also evaluated. The Bru1 frequency among cultivars (73.5%) suggests this gene is the prevalent source of brown rust resistance in Brazilian sugarcane breeding programmes. Most of the cultivars known to be resistant were positive for Bru1, although other genes for resistance could be present in lines not having Bru1. Only 17.8% of the basic germplasm accessions were positive for the Bru1 gene, and a low correlation between Bru1 diagnostic markers and brown rust severity was observed for basic germplasm accessions. Overall, Bru1 diagnostic markers proved to be efficient identifying resistant cultivars and clones and have potential to be in screening brown rust resistance in Brazilian breeding programmes.     

Diversity of soil-dwelling Trichoderma in Colombia and their potential as biocontrol agents against the phytopathogenic fungus Sclerotinia sclerotiorum (Lib.) de Bary

Twenty-one isolates of Trichoderma spp. were collected from eight states in Colombia and characterized based on the 5′ end of the translation elongation factor-1α (EF1-α1) gene and RNA polymerase II gene encoding the second largest protein subunit (RPB2) by using mixed primers. Seven species of soil-dwelling Trichoderma were found: T. atroviride, T. koningiopsis, T. asperellum, T. spirale, T. harzianum, T. brevicompactum and T. longibrachiatum. Species identifications based on the EF1-α1 gene were consistent with those obtained from the RPB2 gene. Phylogenetic analyses with high bootstrap values supported the validity of the identification of all isolates. These results suggest that using the combination of the genes EF1-α1 and RPB2 is highly reliable for molecular characterization of Trichoderma species. Trichoderma asperellum Th034, T. atroviride Th002 and T. harzianum Th203 prevented germination of more than 70 % of sclerotia of Sclerotinia sclerotiorum in bioassay tests and are promising biological control agents. No relationship between mycelium growth rate and parasitism level was found.     

Use of Ozonization for the Treatment of Dye Wastewaters Containing Rhodamine B in the Agate Industry

The industrial processing of precious stones is a source of revenue for several Brazilian towns, especially in the state of Rio Grande do Sul. Given the growing number of small-sized companies that process precious stones, wastewater production is inevitable and is a cause for concern inasmuch as preservation of nature is considered. The present study investigates the detoxification of the wastewater produced by the process of rhodamine B dyeing using oxidation processes. Ozonization (O₃), ultraviolet irradiation (UV), and O₃/UV methods were assessed. Some of the parameters used to measure the efficiency of the analyzed treatments included COD, ecotoxicity (Daphnia magna), cytotoxicity, and genotoxicity assays (Allium cepa assays). Results show predominance of negative and local environmental impacts, which are reversible in more than 70% of cases. The major proposed reversibility measures were the change in the process layout and dye wastewater segregation. Among the analyzed methods, ozonization proved to be more efficient in decolorization, with 60 min of treatment, pH = 9 and dosage of 5.705 mg O₃/mg of rhodamine B. A pseudo first-order reaction, with a kinetic constant of 7.5 × 10⁻² min⁻¹, was observed. The cytotoxic and genotoxic effects were assessed for both raw and treated wastewaters. Despite complete decolorization, cytotoxicity and genotoxicity assays revealed an EC₅₀ of 28.6, in addition to chromosome aberrations in 40% of dividing cells for the treated wastewater.     

Plant growth promotion by Bacillus amyloliquefaciens FZB45 depends on inoculum rate and P-related soil properties

We have studied the effect of soil P-related properties and inoculum concentration on plant growth promotion by the phytase-producing strain Bacillus amyloliquefaciens FZB45. The response (shoot fresh weight/P_i content) of a mycorrhizal-independent plant, Chinese cabbage, was evaluated in a soil with well-defined P-related properties. Two inoculum concentrations were evaluated under four P regimes: no P addition, inorganic P, and two levels of phytate. Significant interaction between P regime and bacterial inoculation was found. FZB45 only promoted plant growth and P uptake at the higher rate of phytate, confirming that phytase activity is its major mechanism and that is limited by soil phytate availability. The effect caused by the lower inoculum concentration was superior than that by the higher, suggesting the simultaneous involvement of a direct effect. This effect was confirmed by a soilless test, which showed a hormone-like response. FZB45 produced IAA in vitro, but its role is to be determined. These results demonstrate that soil modulates the performance of plant growth-promoting rhizobacteria in a specific manner, consistent to the mechanisms of action involved. Determination of those mechanisms and their modulating factors helps predict conditions where plant growth promotion will result, an important step in increasing the consistency of PGPR.     

Cassava starch factory residues in the diet of slow-growing broilers

The objective of this study was to evaluate the effect of inclusion of dehydrated cassava starch residue (DCSR) on the performance, gastrointestinal tract characteristics and carcass traits of ISA Label JA57 slow-growing broilers. A total of 510 broilers at 21 were distributed in a randomized experimental design with 5 treatments (2, 4, 6, 8, and 10 % DCSR inclusion) and a control group, 5 replicates, and 17 birds per experimental unit. The DCSR inclusion from 21 to 49 days of age negatively influenced (P?P?>?0.05) feed conversion in the broilers with increasing of DCSR inclusion. From 21 to 79 days, DCSR inclusion impaired (P?P?P?P?>?0.05) the other parameters of carcass quality and yield, cuts, and percentage of abdominal fat. In conclusion, DCSR inclusion levels above 2 % compromised broiler performance.     

Trypanocidal properties of Mikania stipulacea and Mikania hoehnei isolated terpenoids

The in vitro trypanocidal properties of isolated terpenoids from Mikania stipulacea and Mikania hoehnei were investigated in Trypanosoma cruzi Y strain. Both compounds, the diterpene ent-9alpha-hydroxy-15beta-E-cinnamoyloxy-16-kauren-19-oic acid (1) and the sesquiterpene lactone 8beta-hydroxyzaluzanin D (2) were active.     

Seasonal changes in the incidence of apomixis of diploid,triploid, and tetraploid plants of Paspalum cromyorrhizon

Summary Changes in incidence of apomixis were determined at different intervals of the flowering period in a highly sexual diploid cytotype of Paspalum cromyorrhizon Trin., a natural tetraploid cytotype of the same species, and in the triploid and tetraploid intraspecific hybrids that were produced by pollinating the 2x cytotype with pollen of the tetraploid. Reproductive behaviour was determined from observations of embryo sacs in mature ovules. Gametophytic apomixis in this species in characterized by aposporous embryo sacs which differ from normal sacs by their number, orientation inside the ovule, their dimensions and shape, and the absence of antipodal cells.The potential for apomictic reproduction increased in relation to the ploidy level, suggesting a gene dosage effect in the incidence of apomixis. In the three ploidy levels, the highest incidence of apomixis was observed when the plants reached the maximum number of flowering heads. These findings suggest that the same environmental conditions that favour flowering should also be responsible for increasing the incidence of apomixis. An additional experiment under controlled conditions indicated that the light regime should be one of the factors that govern the amount of apomictic reproduction. Thus, polyploidy and apomixis should be of special significance in the dispersion and evolution of this grass species. The 4x facultative apomictic cytotype is far more frequent in nature than the highly sexual 2x. Moreover, most of the seeds produced in a flowering season should arise asexually. So, apomixis rapidly increases the number of plants bearing the successful maternal genotype, and sexual reproduction becomes important in adverse environmental conditions.     

A radio pulsar spinning at 716 Hz

We have discovered a 716-hertz eclipsing binary radio pulsar in the globular cluster Terzan 5 using the Green Bank Telescope. It is the fastest spinning neutron star found to date, breaking the 24-year record held by the 642-hertz pulsar B1937+21. The difficulty in detecting this pulsar, because of its very low flux density and high eclipse fraction (approximately 40% of the orbit), suggests that even faster spinning neutron stars exist. If the pulsar has a mass less than twice the mass of the Sun, then its radius must be constrained by the spin rate to be <16 kilometers. The short period of this pulsar also constrains models that suggest that gravitational radiation, through an r-mode (Rossby wave) instability, limits the maximum spin frequency of neutron stars.