Effects of Glyphosate on Somatic and Ovarian Growth in the Estuarine Crab <Emphasis Type="Italic">Neohelice granulata</Emphasis>, During the Pre-Reproductive Period

Adult females of the estuarine crab Neohelice granulata were exposed during the 3-month pre-reproductive period (winter) to the herbicide glyphosate, the most used pesticide in Argentina, at three different concentrations (0.02, 0.2, and 1 mg/L, as active ingredient). At the end of the in vivo assay, the body weight gain and the ovarian growth were estimated, the last one in terms of the gonadosomatic index (GSI), the relative proportion of the different kind of oocytes, and their relative size. A decrease in the body weight gain was observed by effect of pure glyphosate, at all concentrations assayed. Although no differences in either the GSI or vitellogenic protein content of the ovary were noted between any glyphosate concentration and control, a higher proportion of reabsorbed vitellogenic oocytes was observed in the ovaries of crabs exposed to glyphosate at 1 mg/L, together with an increased area of previtellogenic oocytes. These effects were confirmed in vitro, at a glyphosate concentration of 0.2 mg/L. In fact, a higher area of previtellogenic oocytes was seen when glyphosate was added to the culture medium containing ovarian tissue, but a significant higher incidence of reabsorbed vitellogenic oocytes was seen only when eyestalk tissue was also added to the vials, suggesting that the secretion of some neurohormone involved in reabsorption is enhanced. The obtained results indicate that glyphosate is able to harm, in the studied species, both somatic and the ovarian growth.     

N-acyl-homoserine lactones from Enterobacter sakazakii (Cronobacter spp.) and their degradation by Bacillus cereus enzymes

A chemical study of acyl-homoserine lactones (acyl-HSLs) produced by Enterobacter sakazakii resulted in the identification of three molecules: (S)-N-heptanoyl-HSL, (S)-N-dodecanoyl-HSL and (S)-N-tetradecanoyl-HSL. Mixed cultures of E. sakazakii and Bacillus cereus depleted E. sakazakii acyl-HSLs, suggesting acyl-HSL degradation by B. cereus hydrolases (hydrolysis of the lactone or amide moiety). The expression of B. cereus acyl-HSL lactonase and acyl-homoserine acylase was confirmed by monitoring the biotransformation of (S)-N-dodecanoyl-HSL into (S)-N-dodecanoyl-homoserine, dodecanoic acid and homoserine in the presence of B. cereus whole cells, using electrospray-mass spectrometry (ESI-MS).     

Effect of peripartal administration of mycobacterium cell wall fraction on health and fertility of Holstein cows under organic-certified management

The main objective of this study was to evaluate the effect of peripartal administration of a commercially available nonspecific immune stimulant (mycobacterium cell wall fraction; MCWF [Amplimune, NovaVive Inc., Napanee, ON, Canada]) on the incidence of disease during early lactation and subsequent fertility of dairy cows. A second objective was to characterize the dynamics of circulating white blood cells (WBC) and metabolic markers following treatment administration. Cows in an United States Department of Agriculture (USDA) organic-certified dairy herd were blocked by parity and, based on sequential calving dates, randomly assigned to receive two injections (5 mL s.c.) of either a placebo (saline solution) as a control (CON; n = 71) or MCWF (n = 65) at enrollment (7 d before expected calving) and within 24 h after calving. Blood samples were collected from a subsample of the study population (MCWF = 16; CON = 18) for WBC count at enrollment, at day 2 post enrollment, and at days 1, 3, 7, and 14 after calving. Serum fatty acids, beta-hydroxybutyrate, and Ca concentrations were determined at days 1 and 7 postpartum (MCWF = 21; CON = 21). Main outcome variables included incidence risk of peripartal and early lactation health disorders and pregnancy at first artificial insemination (AI), at 100, and at 150 days in milk (DIM). In addition, the average daily milk yield up to 90 DIM and death and live culling before 305 DIM were compared. Treatment effects were assessed using multivariable logistic regression, time-to-event analyses, and repeated measures analysis of variance (ANOVA). A treatment effect on the incidence risk of some of the health disorders in the study was established. Incidence risk of metritis and clinical mastitis <28 DIM was smaller in MCWF than in CON cows (36.9% vs. 50.7% and 6.3% vs. 19.7%, respectively). On the contrary, the incidence risk of respiratory disease <28 DIM was smaller in CON (0%) than in MCWF (7.7%). Reproductive performance of multiparous cows was affected by MCWF administration: pregnancy at first AI and pregnancy at 100 and 150 DIM were greater in MCWF than in CON (35.6% vs. 19.2%; 51.1% vs. 25.0%; and 64.4% vs. 40.4%, respectively). Overall, median intervals from calving to pregnancy were 90 vs. 121 d in MCWF and CON cows, respectively. No treatment effects on the dynamics of circulating WBC or in postpartum metabolic status were established. No differences for milk yield or for the proportion of cows that survived up to 305 DIM were determined, although cows in MCWF left the herd earlier than cows in CON. In conclusion, incidence risks of metritis and mastitis in early lactation were smaller in cows receiving MCWF, whereas the incidence risk of respiratory disease was smaller in CON. Fertility significantly improved in MCWF compared with CON cows. As this study was performed in an organic-certified dairy, specific health and reproductive management practices may affect the external validity of the current findings.     

Effect of shade on biomass accumulation and partitioning for Eucalyptus camaldulensis sprouts

ABSTRACT

Eucalyptus is widely cultivated in homogeneous monocultures throughout the world alongside plants of the same age. Furthermore, the productivity of forest stands is highly dependent on how solar radiation is intercepted and used. Meanwhile, it is possible to consider cultivating trees of different ages in the same area, and thus under different regimes of available solar radiation, creating a sequence of plantings and harvestings and to develop Eucalyptus-based agroforestry systems. We have examined biomass accumulation of Eucalyptus camaldulensis along a shade gradient. Eucalyptus trees presented power-law responses to increasing irradiance for biomass, indicating it has low plasticity and is unable to maintain growth under lower irradiance levels. Biomass partitioning showed no dependence on available irradiation. Leaf density presented very little increase toward sunnier places meaning that an increment in Eucalyptus biomass would be mostly due to its increase in size and thus higher radiation interception. Careful management of shade will be a key consideration for the integration of Eucalyptus into agroforestry. With knowledge of the growth habits of different species, we will have the potential to propose more perennial ways in which to manage land and reduce anthropogenic disturbances by avoiding clear-cuts of areas that removes all plant structures.     

Natural enemies of the South American moth, Tuta absoluta, in Europe, North Africa and Middle East, and their potential use in pest control strategies

The South American tomato leafminer, Tuta absoluta Meyrick (Lepidoptera: Gelechiidae), is an invasive Neotropical pest. After its first detection in Europe, it rapidly invaded more than 30 Western Palaearctic countries becoming a serious agricultural threat to tomato production in both protected and open-field crops. Among the pest control tactics against exotic pests, biological control using indigenous natural enemies is one of the most promising. Here, available data on the Afro-Eurasian natural enemies of T. absoluta are compiled. Then, their potential for inclusion in sustainable pest control packages is discussed providing relevant examples. Collections were conducted in 12 countries, both in open-field and protected susceptible crops, as well as in wild flora and/or using infested sentinel plants. More than 70 arthropod species, 20 % predators and 80 % parasitoids, were recorded attacking the new pest so far. Among the recovered indigenous natural enemies, only few parasitoid species, namely, some eulophid and braconid wasps, and especially mirid predators, have promising potential to be included in effective and environmentally friendly management strategies for the pest in the newly invaded areas. Finally, a brief outlook of the future research and applications of indigenous T. absoluta biological control agents are provided.     

Acquisition capability of the grapevine Flavescence dorée by the leafhopper vector Scaphoideus titanus Ball correlates with phytoplasma titre in the source plant

Flavescence dorée (FD) is one of the most economically important grapevine diseases in Southern Europe, and it is associated with phytoplasmas, phloem-limited wall-less bacteria. Recovery from disease naturally occurs in infected grapevines during the following seasons after infection. The capability of the leafhopper vector Scaphoideus titanus to acquire FD phytoplasma (FDP) from recovered and infected grapevines of Barbera and Nebbiolo varieties was investigated in North-western Italy vineyards monitored from 2007 to 2011. Pathogen concentration was quantified by real-time PCR in FDP-infected grapevines and broad beans, also used as source plants under controlled conditions, to correlate acquisition capabilities and phytoplasma titre in source plants. S. titanus acquired FDP from infected, but not from recovered, grapevines. FDP titre was higher in Barbera than in Nebbiolo and higher in summer than in spring, and acquisition efficiency and pathogen titre in source plants were positively correlated, both in field and laboratory conditions. Recovered plants do not represent a source of inoculum for the vector and therefore do not contribute to FDP spread. The inability of recovered plants to serve as FDP acquisition sources for the vector as well as the effect of the season and of the two grapevine varieties on the FDP acquisition efficiency are relevant results to re-design disease management practices, especially since insecticide treatments against the vector are not fully effective, and newly designed successful control strategies are required.     

Antioxidant, icthyotoxicity and brine shrimp lethality tests of Magonia glabrata

The ethanolic extract of the fruit bark from Magonia glabrata yielded shikimic acid, scopoletin, sitosterol glycoside and 2-O-methyl-l-inositol. Antioxidant, icthyotoxicity and brine shrimp lethality activities were observed in this extract. The major constituent, 2-O-methyl-l-inositol, was found to be inactive in two assays but showed moderate activity as a radical scavenger.     

Molluscicidal activity of Solanum species of the Northeast of Brazil on Biomphalaria glabrata

Seven species of Solanum were screened for their molluscicidal properties against Biomphalaria glabrata, the intermediated host of Schistosoma mansoni, Solanum agrarium, S. jabrense, S. melissarum, S. megalonyx, S. paludosum, S. paraibanum and S. stipulaceum. Four extracts showed molluscicidal activity with LC(50) from 22 to 56 microg/ml.     

Is community-based forest management more effective than protected areas?: A comparison of land use/land cover change in two neighboring study areas of the Central Yucatan Peninsula,Mexico

The importance of the role of local community forestry institutions towards forest conservation is exemplified through a comparison of two adjacent areas within the Central Yucatan Peninsular Region (CYPR) in which Land-Use Cover Change (LUCC) analyses were conducted. We also used logistic regression analyses to examine key environmental, socioeconomic and institutional drivers associated with deforestation. One of the areas, La Montaña (LM) at Hopelchen, Campeche, is part of the northern section and buffer zone of the Calakmul Biosphere Reserve (CBR) as well as part of the Mesoamerican Biological Corridor. LM is an agricultural forest frontier region economically dependent on productive activities. The other study, Zona Maya (ZM), found at the municipality of Felipe Carrillo Puerto in Quintana is characterized by having developed community-based forestry enterprises with world wide recognition. In addition, the major tourism industry in nearby Cancun and Riviera Maya provide an important source of off-farm labor and temporary migration. Results show contrasting annual deforestation rates among the two study areas, being greater in the Campeche site (0.7% from 2000 to 2005) compared to Quintana Roo (−0.002% from 2000 to 2004). Logistic regression results show that the occurrence of land clearing at LM is significantly related to demographic variables as well as soil-environment types and conservation status did not reveal to relate to LUCC processes at all. At Quintana Roo, despite twice the population density, population variables at large did not strongly correlate to forest clearing. Rather forest conservation or maintenance was shown to be influenced by local community forestry institutions and a landscape zoning provided by larger management goals from the part of the communities. Greater availability of wage labor for the prominent tourism economy may also reflect a lesser dependence on agriculture and contribute to the much lower deforestation rate. Nonetheless, results show that community forest management can play an effective role in forest conservation. We argue for a regional land use management approach as a conservation strategy in which local inhabitants are considered key actors.     

Photocatalytic Degradation of Emerging Contaminants: Artificial Sweeteners

Artificial sweeteners are food additives widely used, mainly in reduced sugar or sugar-free foods and beverages. Acesulfame potassium (ACE-K) and sodium saccharin (SAC) are among the most widely consumed sweeteners worldwide. These compounds when ingested are not metabolized by the body, being excreted unchanged. They arrive at treatment plants, where they are partially degraded and consequently released directly into water bodies. For this reason, artificial sweeteners have been detected in the most diverse aquatic environments, being recognized as emerging contaminants. In this work, aqueous solutions of ACE-K and SAC, submitted to heterogeneous photocatalysis (TiO₂/UV-A) for 60 min, showed degradations of more than 99% and maximum mineralization of 57% for ACE-K and 49% for SAC. The effects of certain variables were evaluated, with pH having a greater influence on the degradation of acesulfame and the mass of semiconductor on that of saccharin. The degradation of ACE-K and SAC followed a pseudo-first-order kinetic model according to the Langmuir–Hinshelwood model. Assays using Artemia salina as the test organism demonstrated the low toxicity of the photocatalyzed solutions of ACE-K and SAC. The contribution of different reactive species to the photocatalysis was investigated using specific radical inhibitors; the results indicate that singlet oxygen (¹O₂) has a fundamental role in the photocatalytic degradation of ACE-K and SAC.

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