Carotenoid composition and heterotic effect in selected Italian maize germplasm

Maize (Zea mays L.) is a promising crop for improving the nutritional quality of foods, because of the presence of broad natural variability for the content of carotenoids. One hundred Italian and nine public lines were screened by PCR to identify the alleles of Hydroxylase3 (HYD3) and Lycopene epsilon cyclase (LCYE) genes, codifying for key enzymes of the carotenoid pathway and associated with high or low β-carotene contents. Nineteen selected genotypes carrying different alleles were grown in 2011 and/or 2012, and used to obtain F1 seeds. HPLC analysis highlighted the richness in zeaxanthin and β-cryptoxanthin of Italian germplasm (mean values 12.63 and 2.88 mg/kg d.m., respectively). The percentage of positive and significant mid parent heterosis (MPH) and best parent heterosis (BPH) values (51% and 29%) indicated the presence of a high heterotic response for carotenoids. The compounds on the same branch of the pathway were found to be positively correlated; on the contrary, no consistent correlation was observed between the different HYD3 alleles and β-carotene content. Finally, total antioxidant capacity (TAC) was also measured. These lines resulted therefore as interesting raw materials for the market of maize-based foods.     

Nitrogen mineralization from an organically managed soil and nitrogen accumulation in lettuce

The potential of an organically managed Cambic Arenosol to supply nitrogen (N) from either an applied commercial organic fertilizer (granulated hen manure), a compost produced on‐farm, or four different mixtures of both fertilizers was studied in a laboratory incubation and a pot experiment with lettuce. In the incubation experiment, a significant higher apparent N mineralization occurred after hen‐manure application (53.4% of the organic N applied) compared to compost (4.5%) or mixed‐fertilizer application (8.7% to 16.7%). The apparent N mineralization in a mixed treatment consisting of compost and half rate of hen manure (15.4% of the organic N applied) was significantly higher than that estimated based on the N mineralization for compost and hen‐manure treatments (7.6%), proving that a combined application of both fertilizers enhanced organic‐N mineralization when compared to separate fertilizer supply. In the pot experiment, a higher lettuce fresh‐matter yield was obtained with hen manure (1.9 kg m^–2) than with compost (1.7 kg m^–2) or unfertilized control treatment (1.3 kg m^–2). Combined application of compost with only a half rate of hen manure led to yields (2.0 kg m^–2) equal to those obtained with only hen manure. A good correlation was observed between the N‐mineralization incubation data and the N accumulated by lettuce plants in the pot experiment (r = 0.983). Hence, in the organic production of baby‐leaf lettuce, a mixture of compost and hen manure appears to be a good fertilization alternative, since it allows a reduction by half of the typical amount of commercial fertilizer usually applied (granulated hen manure), cutting fertilization costs, and providing an amount of available N that allows maintaining lettuce yields.     

Compatibility of the fungus Metarhizium anisopliae and deltamethrin to control a resistant strain of Boophilus microplus tick

The tick Boophilus microplus causes economic impact to cattle producers and has a great capacity to develop resistance to chemical acaricides. It is very important the development of new techniques to complement the control of this parasitosis. Biological control is a promising option to maintain acceptable levels of tick populations in cattle. Therefore, the present study evaluated the association of deltamethrin and the entomopathogenic fungus Metarhizium anisopliae against B. microplus larvae resistant to pyrethroid. The synthetic pyrethroid, deltamethrin, was used at concentrations of 0.39, 0.78, 1.56, 3.12 and 6.12 ppm, M. anisopliae was used at concentrations of 10(5), 10(6), 10(7) and 10(8) conidia ml(-1). Their associations were also evaluated in in vitro tests. The assays showed that the tick strain is resistant to deltamethrin, but high mortality rates were observed when deltamethrin was associated with the entomopathogen. The larvae's mortality rates ranged from 7 to 36.5% for the different concentrations of deltamethrin, however, for the different concentrations of M. anisopliae, the mortality rates ranged from 10 to 96.9%. Mortality rates were proportional to the concentrations used for both deltamethrin and the fungus. Predominantly, the association of pyrethroid and fungus resulted in higher larvae mortalility rates than those obtained with the respective non-associated concentrations. Thus, the present study indicates that this association can be used as a tool for integrated control of the tick B. microplus.     

Detection of Ehrlichia canis by polymerase chain reaction in dogs from Portugal

Antibodies against Ehrlichia canis, the cause of canine monocytic ehrlichiosis, have been reported previously in clinically ill and stray dogs from Portugal. In this study, the 16S rRNA gene of E. canis was detected by the polymerase chain reaction (PCR) in 12/55 (22%) of dogs with suspected tick-borne disease in the Algarve region in Portugal.     

Effect of antivenin dose on outcome from crotalid envenomation: 218 dogs (1988–2006)

Objective – To determine whether the dose of antivenin administered is associated with a difference in survival of crotalid‐envenomated dogs. A secondary objective was to determine whether other covariables affect survival. Design – Retrospective study (1988–2006). Setting – Private referral center and university small animal teaching hospital. Animals – Two hundred and eighteen dogs with evidence of crotalid envenomation and treatment with equine‐derived antivenin. Interventions – Administration of antivenin. Measurements and Main Results – Patient signalment, physical and clinicopathologic data at time of presentation, treatments, complications of antivenin therapy, length and cost of hospitalization, and outcome were recorded. Confidence intervals were determined for the difference in median number of vials administered and for median dosage for patients that lived versus died. Penalized logistic regression was performed to evaluate the effect of other covariables on survival. The median age of affected dogs was 3 years (range 6 w–12 y) with a median weight of 25.7 kg (range 1.95–86.4 kg). The median number of antivenin vials administered was 1.0 (range 1.0–10.0). Acute and chronic reactions were reported in 7% (16/218) and 0.9% (2/218) of dogs, respectively. Nine of 218 dogs (4.1%) died. The median number of vials administered to the nonsurvivors and survivors were 2.0 (range 1–5 vials) and 1.0 (range 1–10 vials), respectively. The median number of vials received was significantly different in dogs that died versus those that lived (P<0.05). Increased heart rate (P=0.02) and petechiation (P=0.04) were associated with decreased likelihood of survival, while diphenhydramine (P=0.02) and fluoroquinolone (P=0.046) administration was associated with increased likelihood of survival. The median duration of hospitalization was 1.0 day (range 2 h–22 d). The median cost of hospitalization was US$1592.00 (range US$267.20–US$6738.00). Conclusion – The administration of more vials of antivenin is potentially associated with negative outcome; however, a causal relationship has not been established. Controlled, prospective studies are needed to optimize antivenin administration.     

Management of advanced regeneration in secondary forests of the Brazilian Amazon

Gap formation is a critical process for plant establishment that may be absent or infrequent in second-growth forests, negatively influencing their ability to become diverse mature forest. I simulated treefall gaps within a 10-year-old secondary forest established on a clear-cut area, because cut areas may have a greater potential for economic exploitation than areas used for pastures and shifting cultivation. I explored the effects of varying degrees of canopy opening on the growth of plants already established as advanced regeneration. Five intensities of canopy opening were created: total removal (100%), 80–90%, 50–60%, 20–30% and a 0% control. Only trees >5 cm DBH were cut. The established plant community was diverse, and comprised 37 families and 126 species and morpho-species, of which 72% had some use reported in the literature. I found that the canopy opening treatments resulted in very little disturbance to the established seedling and sapling community, with no significant increase in mortality, but had a strong positive effect on their growth. Light levels reaching the understory were increased from 1% of incident photosynthetic active radiation in control plots to 35% in 100% canopy opening plots. During the first year, differences in plant growth were not significant, but by the second year, differential plant growth associated with canopy opening became evident. Most seedlings (51%) grew approximately 25 cm in height, and approximately one quarter grew more than 25 cm. Only 2.6% of the seedlings decreased in height, and 12% did not grow at all. Fifty percent canopy removal resulted in an almost threefold increase in plant height compared to control plots (0.52 ± 0.4 m and 0.20 ± 0.2 m, respectively), and was not significantly different from 80 or 100% removal. This indicates that intermediate levels of canopy removal had positive effects and total removal was unnecessary to stimulate the best growth responses. I conclude that regeneration of diverse mature forest can be accelerated under some conditions by partial removal of secondary forest canopy.     

Changes in the activity and abundance of the soil microbial community in response to the nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP)

Purpose

The application of organic and inorganic fertilizers to soil can result in increased gaseous emissions, such as NH₃, N₂O, CO₂, and CH₄, as well as nitrate leaching, contributing to climate warming and ground and surface water pollution, particularly in regions with hot climates, where high temperatures and high soil nitrification rates often occur. The use of nitrification inhibitors (NIs) has been shown to effectively decrease nitrogen (N) losses from the soil-plant system.

Materials and methods

Non-disruptive laboratory incubation experiments were conducted to assess the extent to which temperature (20 and 30 °C) and nutrient source (mineral and organic fertilizers) influence the rate of carbon (C)- and N-related microbial processes in soil in response to the NI 3,4-dimethylpyrazole phosphate (DMPP). Furthermore, short-term changes in the ability of microbes to degrade C substrates were evaluated in disruptive soil microcosms using microbial community-level physiological profiling and the abundance of the bacterial 16S rRNA gene as a measure of total bacterial population size.

Results and discussion

DMPP reduced net nitrification after 2 and 4 weeks of incubation at 30 and 20 °C by an average of 78.3 and 84.5 %, respectively, and with similar dynamics for mineral or organic fertilization. The addition of labile organic matter with cattle effluent led to a rapid increase in C mineralization that was significantly reduced by DMPP at both temperatures, whereas no changes could be detected after the addition of mineral fertilizer. The culturable heterotrophic microorganisms showed metabolic diversification in the oxidation of C sources, with organic fertilizer playing a major role in the substrate utilization patterns during the first week of incubation and the DMPP effects prevailing from day 14 until day 28. Furthermore, the copy number of the bacterial 16S rRNA gene was reduced by the application of DMPP and organic fertilizer after 28 days.

Conclusions

Our results show the marked efficiency of DMPP as an NI at elevated temperatures of incubation and when associated with both mineral and organic fertilization, providing support for its use as a tool to mitigate N losses in Mediterranean ecosystems. However, we also observed impaired C respiration rates and bacterial abundances, as well as shifts in community-level physiological profiles in soil, possibly indicating a short-term effect of DMPP and organic fertilizers on non-target C-related processes and microorganisms.

     

In-soil potassium sensor system

A potentiometric sensor system based on potassium ion-selective electrodes was developed for agricultural purposes. Sensors were built using PVC ion-selective membranes over an inner solid contact prepared with graphite-epoxy composites. A copper plate was used as a reference electrode. A two-stage electronic circuit composed of current and voltage amplifiers was designed to interface the sensors to a distributed data acquisition system. Three ion-selective sensors and three off-the-shelf temperature sensors and their associated circuits were mounted in a PVC tube to set up a soil probe. The electronic controls were placed in an airtight box fixed at the upper part of the probe. The system was evaluated in the field, where the sensors presented sensibility within the range of 69-71 mV dec(-)(1). Extracts of soil samples were analyzed by a current flame photometry approach, and the results, compared with the probe measurements, showed a linear relationship (r (2) = 0.992 and 0.995, respectively, to 5 and 20 cm depths), which implies viability and instrumentation reliability for agricultural applications.     

Composition of the essential oil of Mentha microphylla from the Gennargentu Mountains (Sardinia,Italy)

The essential oil obtained by hydrodistillation of the fresh aerial parts of Mentha microphylla C. Kock (Lamiaceae) collected on the Gennargentu Mountains (Sardinia, Italy) has been investigated by gas chromatography (GC) and GC/mass spectrometry (MS). The main constituents that resulted were pulegone (34.1%), piperitenone oxide (32.9%), and piperitenone (11.3%). The presence of small amounts of compounds such as ethyl hexanoate, 1-octen-3-ol, nonanal, and ethyl 2-methylbutanoate could justify the particular odorous profile of the plant, resembling the aroma of milk and other dairy products such as mozzarella.     

Forest fragmentation differentially affects seed dispersal of large and small-seeded tropical trees

The responses of plant-animal interactions to forest fragmentation can vary. We hypothesized that large-seeded plant species would be more susceptible to forest fragmentation than small-seeded species because large-seeded species rely on a few, extinction prone dispersers. We compared seed dispersal of the large-seeded, mammal dispersed Duckeodendron cestroides and the small-seeded, avian dispersed Bocageopsis multiflora. The number, percentage, distance, and distributions of dispersed seeds were all reduced in fragments for Duckeodendron but not for Bocageopsis. Other fragmentation research in tropical communities supports this hypothesis through three lines of evidence: (1) Large-seeded plant species are more prone to extinction, (2) Fragmentation restricts or alters the movement of large animal dispersers more than small dispersers, and (3) Large and small-seeded species seem to be differentially linked to primary and secondary forest habitats. Therefore, small-seeded plants may be more resilient to forest fragmentation while large-seeded species may be more susceptible and should be a priority for conservation.