Host plant preference of aphids, thrips and spider mites on GNA-expressing and control potatoes

The effect of snowdrop lectin (Galanthus nivalis agglutinin: GNA) expression on host-plant preference was examined with a two-choice disc test. Discrimination between a transgenic potato [Solanum tuberosum (Solanaceae)] capable of synthesizing GNA, and an isogenic cultivar, was studied under laboratory conditions using the glasshouse potato aphidAulacorthum solani (Hemiptera: Aphididae), the onion thripThrips tabaci (Thysanoptera: Thripidae), and the two-spotted spider miteTetranychus urticae (Acari: Tetranychidae). Adults of these species were placed individually on leaf discs (one half transgenic and one half control) and observed 1, 24, 48, 72 and 96 h after release, at which times also the distributions ofA. solani nymphs andT. urticae eggs on the discs were recorded. Aphids were found more frequently on control leaves at all observation periods, with the highest bias observed at 72 h (only 35.9% of all aphids were found on the GNA halves). Similarly, more aphid nymphs (57.6% of the total) were found on isogenic half-discs. The percentage of thrips found on GNA halves ranged from 36.8% to 48.4%, with significant control-potato bias at the first three observations. Contrary to this, the proportion ofT. urticae females found on GNA halves was significantly lower than the expected proportion (0.5) at 72 and 96 h, with a minimum of 34.0% on GNA. The distribution of spider mite eggs reflected the observed biased distribution of females (only 34.1% of all eggs were laid on GNA half-discs). These results indicate that potatoes expressing GNA for resistance against aphids are less preferred than an isogenic cultivar by all three tested species under a choice test condition using excised leaves.     

Shear wave elastography evaluation of cats with chronic kidney disease

Chronic kidney disease (CKD) is a major health condition in cats that can lead to poor quality of life and financial implications for therapy. Currently staging and identification of CKD is limited by diagnostic testing such as creatinine and urine-specific gravity, which do not change until late in the disease course. Other methods to evaluate CKD would be valuable in the clinical setting. Shear wave elastography is one novel ultrasound method, which has shown promise in identifying increases in tissue stiffness and identifying CKD in people. As CKD is often histologically characterized by tubulointerstitial fibrosis, shear wave elastography has the potential to identify CKD and differentiate between stages of CKD in cats. This prospective observational case-control study with 78 cats found no difference in shear wave velocities between groups (P = 0.33), a contradictory finding to one prior publication. There was no effect of weight (P = 0.65), nor the presence of mineralization (P = 0.31) or infarction (P = 0.52) on cortical shear wave velocities. There was a significant effect of age on shear wave velocity (P = 0.018) where velocities increased with age. The intraclass correlation coefficient was only moderate (0.62). Possible reasons for the difference in results between our work and that published prior, include differences in methodology and differences in instrumentation. Variability in measurements in our population may be due to the effects of respiratory motion or limitations in shear wave elastography software. As such, shear wave elastography is not currently recommended as a tool to evaluate CKD in cats and further work is necessary.     

Speed of reversal of vecuronium neuromuscular block with different doses of neostigmine in anesthetized dogs

Objectives

Neostigmine is routinely used to reverse non-depolarizing neuromuscular block. Given its indirect mechanism, a plateau may exist whereby increasing doses of neostigmine do not result in clinical benefit. This study was designed to measure the speed of reversal of vecuronium-induced neuromuscular block in isoflurane-anesthetized dogs after the administration of three doses of neostigmine as used in clinical practice.

Phenol Biodegradation by <Emphasis Type="Italic">Pseudomonas putida</Emphasis> in an Airlift Reactor: Assessment of Kinetic,Hydrodynamic, and Mass Transfer Parameters

An airlift biofilm reactor was employed to study phenol biodegradation by Pseudomonas putida. Hydrodynamic tests were also conducted in a conventional column to facilitate the comparison of the dynamic behavior in different types of columns. The three-phase airlift column offered better aeration than the conventional column as liquid and solid circulation in the downcomer favored bubble breakup, increasing oxygen dissolved in the liquid phase and favoring the phenol biodegradation process. Kinetic parameters of phenol biodegradation by P. putida were obtained in an agitated batch reactor, with the initial phenol concentration varying from 10 to 750 mg/L. Experimental data were fitted using different microbial growth models found in literature. The Yano and Koga model, which considers the formation of multiple inactive enzyme–substrate complexes, fitted well with our experimental data, with a correlation coefficient, R ² = 0.952. An internal loop airlift bioreactor was used for aerobic phenol biodegradation in which polystyrene particles were utilized to support biomass immobilization. Several tests were performed by varying the influent phenol concentration, hydraulic retention time, upstream flow, and superficial air velocity. It was concluded that until an influent phenol concentration of approximately 300 mg/L, phenol acted as the limiting substrate. For higher phenol concentrations, oxygen became the limiting substrate. An increase in the oxygen concentration resulted in the complete consumption of phenol under high phenol concentration of 500 mg/L.     

Estimating Net Primary Productivity and Carbon Inputs by Soybean Crops in Argentina

Monitoring crop net primary productivity (NPP) and its proportion returned to soil in the form of carbon (C) input is vital to better understand the ecological responses to environmental and anthropogenic changes. However, quantification of NPP and C inputs from cropping systems at a regional scale is challenging due to the temporal and spatial variability of soils, climate, and management practices. The aim of this study was to estimate (i) the NPP from soybean crop [Glycine max (L.) Merr.] and (ii) the C inputs from soybean residues into soils of the Pampas and Extra-Pampas regions of Argentina between 1993 and 2005 using a simple approach based on the crop yield census records, a C budget equation, and crop-specific conversion factors at regional scale. Soybean NPP (t ha^?1 year^?1) at a regional scale was estimated by grain yields and harvested areas reported in the long-term (1993–2005) National database for several districts within each province. The mean annual soybean NPP in the Pampas was 0.3 t ha^?1 higher (P < 0.05) than in the Extra-Pampas, resulting in a higher C input from soybean residues of 0.4 t ha^?1 year^?1 in the Pampas region. Due to improved cultivars and higher nutrient inputs in the Pampas region, the mean NPP and C inputs increased by about 25% from 1999 to 2005. Crop NPP and C inputs from residues into soils play a major role in C dynamics and should be considered for further studies at different scales to understand soil organic C modifications through agricultural changes.     

GC-MS metabolite profiling of <Emphasis Type="Italic">Phytophthora infestans</Emphasis> resistant to metalaxyl

Phytophthora infestans is the most important potato pathogen worldwide. Various alternatives have been used to control the pathogen, including continuous applications of phenylamide fungicides which has caused a rapid development of resistance in populations of P. infestans. Despite the importance of the disease, metabolite profiling of fungicide-resistant P. infestans has not been reported. In vitro resistance of Phytophthora infestans isolates to metalaxyl was characterized and metabolic changes in resistant isolates were evaluated at low (0.5 mg/L) and high (100 mg/L) concentrations of the fungicide. About 70% of the isolates tested showed resistance to metalaxyl and a total of 49 metabolites were differently expressed in resistant isolates growing in the presence of the fungicide. Principal components analysis revealed a distinct metabolite profile of resistant isolates exposed to both low and high levels of metalaxyl. The main metabolites responsible for the clustering in both fungicide concentrations included fatty acids such as hexadecanoic and octadecanoic acids, sugars such as glucose and fructose, aminoacids such as proline and valine, and organic acids such as butanedioic and propanoic acids. Potential resistance-related metabolic pathways are mostly involved in the regulation of the pathogen’s membrane fluidity and included the fatty acid biosynthesis as well as the glycerophospholipid metabolism pathways. This is the first metabolomic-based characterization of fungicide resistance in plant pathogens.     

Search for reservoirs of ‘<Emphasis Type="Italic">Candidatus</Emphasis> Liberibacter solanacearum’ and mollicutes in weeds associated with carrot and celery crops

Currently, the main arthropod vectored pathogens associated with carrot and celery crop diseases are ˋCandidatus Liberibacter solanacearum´, Spiroplasma citri and different phytoplasma species. Mitigation strategies require elucidating whether these pathogens survive in the weeds of these Apiaceae crops, which can act as reservoirs. Weed surveys were conducted in a vegetative cycle (April to October 2012) in the spontaneous vegetation that surrounded crops affected by ˋCa. L. solanacearum´, S. citri and/or phytoplasmas. Sixty-three species of 53 genera that belong to 23 botanical families were collected in the main carrot and celery Spanish production area. Species were identified, estimating coverage and abundance, and conserved in herbarium. Samples were analysed by nested-PCR with universal primers for phytoplasmas detection, and were sequenced for identification purposes; by conventional PCR for S. citri and real-time PCR for ˋCa. L. solanacearum´. The only detected pathogens were ˋCa. Phytoplasma trifolii´ (clover proliferation group 16Sr VI-A) in Amaranthus blitoides and Setaria adhaerens and ˋCa. P. solani´ (stolbur group 16Sr XII-A) in Convolvulus arvensis. These pathogens were also sporadically detected in celery or carrot crops. Unexpectedly, neither ˋCa. L. solanacearum´ nor S. citri was detected in the weed samples, despite the relatively high prevalence of these pathogens (less than 66 % and 25 %, respectively) in the surveyed plots. This suggests that weeds do not play an epidemiological role as reservoirs in the spread of such organisms in the studied region. The use of pathogen-free seed lots and the control of vectors are crucial for preventing the introduction and spread of these economical important pathogens to new areas.     

Helminthiasis characterization and anthelmintic efficacy for ewes and lambs raised in tropical semiarid region

In this study the helminthiasis and anthelmintic effectiveness in ewes and lambs were evaluated in a semiarid region of Brazil. Twelve sheep farms were investigated using semi-structured questionnaires and fecal egg count (FEC) reduction test was employed to analyze the profile of anthelmintic resistance. Groups of at least 10 animals with FEC ≥ 300 were selected. After 12 h of fasting, homogeneous groups of lambs or ewes were treated with albendazole, levamisole moxidectin, or oxfendazole and control groups were not treated. Feces were collected before treatments and 14 days after, and larvae genera were identified after cuprocultures in both periods. Extensive grazing was the predominant creation system, using hybrid Santa Ines animals. The separation by age was promoted in 75% of herds; however, maternity pickets there were only in three farms. The strategic treatments were performed only in 8.4% of sheep farms and 16.6% used the anthelmintic efficacy test and alternated anthelmintic classes after 1 year. The initial FEC means for lambs were significantly higher than ewe FEC averages. For lamb tests, moxidectin and levamisole showed higher efficacy (p ≤ 0.05) than benzimidazoles. For ewe tests, moxidectin and levamisole showed efficiencies >75%. Haemonchus spp. and Trichostrongylus spp. were the most frequent nematodes before treatments and the genus Haemonchus was the most prevalent after anthelmintic treatments (p < 0.05). Variations of anthelmintic susceptibility were observed for categories and herds evaluated, which emphasizes the importance of the effectiveness tests for the choice of anthelmintics for ewes and lambs.     

Tailoring the structure of aminobisphosphonates to target plant P5C reductase

Using the structure of (3,5-dichlorophenyl)aminomethylenebisphosphonic acid as a lead compound, 25 new phosphonates were synthesized and evaluated as possible inhibitors of Arabidopsis thaliana delta1-pyrroline-5-carboxylate (P5C) reductase. Derivatives substituted in the phenyl ring retained the inhibitory potential, though to a different extent. On the contrary any variation in the scaffold, i.e., the replacement of the second phosphonate moiety with a hydroxyl or an amino residue, resulted in a significant loss of biological activity. The availability of several structures capable of interfering with the catalytic mechanism in the micromolar to millimolar range allowed a proper structure-activity relationship analysis, leading us to hypothesize about the steric and electronic requirements for maintenance or enhancement of the inhibitory properties. Reversal experiments with suspension cultured cells provided evidence for the occurrence of enzyme inhibition in vivo. Because in higher plants the step catalyzed by P5C reductase is shared by all pathways leading to proline synthesis, these compounds may be exploited for the design of new substances endowed with herbicidal activity.     

Microalgal Dynamics in Batch Reactors for Municipal Wastewater Treatment Containing Dairy Sewage Water

This study investigates the microalgal community dynamics associated with changes in municipal wastewater quality and discharges from the dairy industry in central Veracruz, Mexico, using an experimental stabilization-reactors system. Thirty one species of microalgae were recorded and 15 physicochemical variables were measured daily over 25 days in pretreated water. The biomass of microalgal groups displayed significant negative correlations with biochemical oxygen demand (BOD), chemical oxygen demand (COD) and total suspend solids (TSS). Conversely, a significant positive correlation was found with dissolved oxygen, pH and nitrates. Using the Canonical Correspondence Analysis we identified an initial anaerobic phase (Phase I), characterized by high BOD, TSS and COD, ammonium and faecal coliforms. This was followed by a transition phase (Phase II), an initial aerobic phase (Phase III), when water quality improved considerably, and finally an aerobic phase (IV) with a high percent reduction in these parameters and almost complete organic load removal. The most abundant species associated with these phases were Arthrospira jenneri (Cyanophyceae) and Coccomonas sp. (Chlorophyceae) in Phase I; Polytomella sp. (Chlorophyceae) in Phase II; Polytoma tetraolare, Chlamydomonas caeca (Chlorophyceae) and some Cyanophyceae including Geitlerinema, Synechocystis, Cyanobium and Glaucospira in Phase III; Carteria sp. (Chlorophyceae), Lepocynclis ovum and Euglena clavata (Euglenophcyeae) in Phase IV. Maximum richness, diversity, and biomass levels occurred during the aerobic phase. Similar to other wastewater treatment systems the high succession rates decreased with reactor stabilization. These findings provide statistical evidence on the suitability of certain microalgae species as indicators of wastewater stabilization reactor status and effluent quality.