Efficiency of diagnostic biomarkers among colonic schistosomiasis Egyptian patients

The schistosomal parasite plays a critical role in the development of malignant lesions in different organs. The pathogenesis of cancer is currently under intense investigation to identify reliable prognostic indices for disease detection. The objective of this paper is to evaluate certain biochemical parameters as diagnostic tools to efficiently differentiate between colonic carcinoma and colonic carcinoma associated with schistosomal infection among Egyptian patients. The parameters under investigation are interleukin 2 (IL-2), tumour necrosis factor alpha (TNF-α), carcinoembryonic antigen (CEA) levels, tissue telomerase, pyruvate kinase (PK), glucose-6-phosphate dehydrogenase (G-6-PD) and lactate dehydrogenase (LDH) enzyme activities. The results revealed a significant elevation in the level of the tumour markers IL-2, TNF-α and CEA as well as the activities of LDH, telomerase and G-6-PD among non-bilharzial and bilharzial colonic cancer groups, with a more potent effect in bilharzial infection-associated colonic cancer. A significant inhibition in PK activity was recorded in the same manner as compared to normal tissues. The efficacy of this biomarker was also evaluated through detecting sensitivity, specificity, negative and positive predictive values. In conclusion, schistosomal colonic carcinoma patients displayed more drastic changes in all parameters under investigation. The combination of the selected parameters succeeded in serving as biomarkers to differentiate between the two malignant types.

Histopathological examination of nerve samples from pure neural leprosy patients: obtaining maximum information to improve diagnostic efficiency

Nerve biopsy examination is an important auxiliary procedure for diagnosing pure neural leprosy (PNL). When acid-fast bacilli (AFB) are not detected in the nerve sample, the value of other nonspecific histological alterations should be considered along with pertinent clinical, electroneuromyographical and laboratory data (the detection of Mycobacterium leprae DNA with polymerase chain reaction and the detection of serum anti-phenolic glycolipid 1 antibodies) to support a possible or probable PNL diagnosis. Three hundred forty nerve samples [144 from PNL patients and 196 from patients with non-leprosy peripheral neuropathies (NLN)] were examined. Both AFB-negative and AFB-positive PNL samples had more frequent histopathological alterations (epithelioid granulomas, mononuclear infiltrates, fibrosis, perineurial and subperineurial oedema and decreased numbers of myelinated fibres) than the NLN group. Multivariate analysis revealed that independently, mononuclear infiltrate and perineurial fibrosis were more common in the PNL group and were able to correctly classify AFB-negative PNL samples. These results indicate that even in the absence of AFB, these histopathological nerve alterations may justify a PNL diagnosis when observed in conjunction with pertinent clinical, epidemiological and laboratory data.

The efficiency of concentration methods used to detect enteric viruses in anaerobically digested sludge

The presence of enteric viruses in biosolids can be underestimated due to the inefficient methods (mainly molecular methods) used to recover the viruses from these matrices. Therefore, the goal of this study was to evaluate the different methods used to recover adenoviruses (AdV), rotavirus species A (RVA), norovirus genogroup II (NoV GII) and the hepatitis A virus (HAV) from biosolid samples at a large urban wastewater treatment plant in Brazil after they had been treated by mesophilic anaerobic digestion. Quantitative polymerase chain reaction (PCR) was used for spiking experiments to compare the detection limits of feasible methods, such as beef extract elution and ultracentrifugation. Tests were performed to detect the inhibition levels and the bacteriophage PP7 was used as an internal control. The results showed that the inhibitors affected the efficiency of the PCR reaction and that beef extract elution is a suitable method for detecting enteric viruses, mainly AdV from biosolid samples. All of the viral groups were detected in the biosolid samples: AdV (90%), RVA, NoV GII (45%) and HAV (18%), indicating the viruses' resistance to the anaerobic treatment process. This is the first study in Brazil to detect the presence of RVA, AdV, NoV GII and HAV in anaerobically digested sludge, highlighting the importance of adequate waste management.

Efficiency of the induced mating technique for Toxorhynchites theobaldi (Diptera, Culicidae)

Toxorhynchites mosquitoes play important ecological roles in aquatic microenvironments, and are frequently investigated as potential biological control agents of mosquito disease vectors. Establishment of Toxorhynchites laboratory colonies can be challenging because for some species, mating and insemination either do not occur or require a prohibitive amount of laboratory space for success. Consequently, artificial insemination techniques have been developed to assist with mass rearing of these species. Herein we describe an adapted protocol for colony establishment of T. theobaldi, a species with broad distribution in the Neotropics. The success of the technique and its implications are discussed.

Soil shear strength under non-irrigated and irrigated short duration grazing systems

Pasture productivity can drop due to soil compaction caused by animal trampling. Physical and mechanical alterations are therefore extremely important indicators for pasture management. The objective of this research was to: draw and evaluate the Mohr failure line of a Red Yellow Latossol under different pasture cycles and natural forest; calculate apparent cohesion; observe possible physical alterations in this soil; and propose a correction factor for stocking rates based on shear strength properties. This study was conducted between March/2006 and March/2007 on the Experimental Farm of Fundação de Ensino Superior de Passos, in Passos, state of Minas Gerais. The total study area covered 6 ha, of which 2 ha were irrigated pasture, 2 ha non-irrigated pasture and 2 ha natural forest. Brachiaria brizantha cv. MG-5 Vitória was used as forage plant. The pasture area was divided into paddocks. The Mohr failure line of samples of a Red Yellow Latossol under irrigated pasture equilibrated at a tension of water content of 6 kPa indicated higher shear strength than under non-irrigated pasture. The shear strength under irrigated pasture and natural forest was higher than under non-irrigated pasture. At a tension of water content of 33 kPa no difference was found in shear strength between management and use. Possible changes in soil structure were caused by apparent cohesion. The values of the correction factor were close to 1, which may indicate a possible soil compaction in prolonged periods of management.

Diversity and efficiency of bradyrhizobium strains isolated from soil samples collected from around sesbania virgata roots using cowpea as trap species

The genetic diversity of ten Bradyrhizobium strains was evaluated for tolerance to high temperatures, to different salinity levels and for the efficiency of symbiosis with cowpea plants (Vigna unguiculata (L.) Walp.). Eight of these strains were isolated from nodules that appeared on cowpea after inoculation with suspensions of soil sampled from around the root system of Sesbania virgata (wand riverhemp) in ecosystems of South Minas Gerais. The other two strains used in our analyses as references, were from the Amazon and are currently recommended as cowpea inoculants. Genetic diversity was analyzed by amplifying repetitive DNA elements with the BOX primer, revealing high genetic diversity with each strain presenting a unique band profile. Leonard jar assays showed that the strains UFLA 03-30 and UFLA 03-38 had the highest N2-fixing potentials in symbiosis with cowpea. These strains had more shoot and nodule dry matter, more shoot N accumulation, and a higher relative efficiency than the strains recommended as inoculants. All strains grew in media of pH levels ranging from 4.0 to 9.0. The strains with the highest N2-fixing efficiencies in symbiosis with cowpea were also tolerant to the greatest number of antibiotics. However, these strains also had the lowest tolerance to high salt concentrations. All strains, with the exceptions of UFLA 03-84 and UFLA 03-37, tolerated temperatures of up to 40 ºC. The genetic and phenotypic characteristics of the eight strains isolated from soils of the same region were highly variable, as well as their symbiotic efficiencies, despite their common origin. This variability highlights the importance of including these tests in the selection of cowpea inoculant strains.

Rhizosphere properties of maize genotypes with contrasting phosphorus efficiency

An experiment was conducted in a growth chamber to evaluate characteristics of the rhizosphere of maize genotypes contrasting in P-use efficiency, by determining length and density of root hairs, the rhizosphere pH and the functional diversity of rhizosphere bacteria. A sample of a Red Oxisol was limed and fertilized with N, K and micronutrients. In the treatment with the highest P level, 174 mg kg-1 P was added. Each experimental unit corresponded to a PVC rhizobox filled with 2.2 dm-3 soil. The experiment was completely randomized with three replications in a 5 x 2 factorial design, corresponding to five genotypes (H1, H2 and H3 = P-efficient hybrids, H4 and H5 = P-inefficient hybrids) and two P levels (low = 3 mg dm-3, high = 29 mg dm-3). It was found that 18 days after transplanting, the nodal roots of the hybrids H3 and H2 had the longest root hairs. In general, the pH in the rhizosphere of the different genotypes was higher than in non-rhizosphere soil, irrespective of the P level. The pH was higher in the rhizosphere of lateral than of nodal roots. At low P levels, the pH variation of the hybrids H2, H4 and H5 was greater in rhizospheric than in non-rhizospheric soil. The functional microbial activity in the rhizosphere of the hybrids H3 and H5 was highest. At low soil P levels, the indices of microbial functional diversity were also higher. The microbial metabolic profile in the rhizosphere of hybrids H1, H2, H3, and H5 remained unaltered when the plants were grown at low P. The variations in the rhizosphere properties could not be related to patterns of P-use efficiency in the tested genotypes.

Assessment of Efficiency and Adequacy of Retention Terraces

Due to losses caused by water erosion, the development of techniques that increase the efficiency of soil conservation practices is fundamental. Terracing of agricultural lands is an important conservation practice. Bearing in mind that improperly built terraces may negatively affect the landscape, the purpose of this work was to evaluate the efficiency as well as the adequacy of retention terraces. Assessments were performed in four terraces implanted in different states, all located in the mideastern region of the state of Minas Gerais. The water storage efficiency of the terraces was determined by comparing the effective with the required storage capacity, as established in the project. Proposals were also made for the adequacy of the assessed terraces, based on the correction of the characteristics that jeopardized storage efficiency. The storage efficiency of three of the four assessed terraces was below the required levels (0.5-13 %). The main properties influencing storage capacity were: uniformity of ridge crest height, terrace end closure, and the cross section finishing. In two of the three low-efficiency terraces, the correction of these characteristics proved sufficient to raise the storage efficiency to nearly 100 %.

Nutrition, dry matter accumulation and partitioning and phosphorus use efficiency of potato grown at different phosphorus levels in nutrient solution

High rates of phosphate fertilizers are applied to potato (Solanum tuberosum L.), which may cause antagonistic interactions with other nutrients and limit crop yields when over-supplied. The purpose of this study was to evaluate the influence of phosphorus (P) levels in nutrient solution on P use efficiency, nutritional status and dry matter (DM) accumulation and partitioning of potato plants cv. Ágata. The experiment was carried out in a greenhouse, arranged in a completely randomized block design with four replications. Treatments consisted of seven P levels in nutrient solution (0, 2, 4, 8, 16, 31, and 48 mg L-1). Plants were harvested after 28 days of growth in nutrient solution, and separated in roots, stems and leaves for evaluations. The treatment effects were analyzed by regression analysis. Phosphorus levels of up to 8 mg L-1 increased the root and shoot DM accumulation, but drastically decreased the root/shoot ratio of potato cv. Ágata. Higher P availability increased P concentration, accumulation and absorption efficiency, but decreased P use efficiency. Higher P levels increased the N, P, Mg, Fe, and Mn concentrations in roots considerably and decreased K, S, Cu, and Zn concentrations. In shoot biomass, N, P, K, and Ca concentrations were significantly increased by P applied in solution, unlike Mg and Cu concentrations. Although higher P levels (> 8 mg L-1) in nutrient solution increased P concentration, accumulation and absorption efficiency, the DM accumulation and partitioning of potato cv. Ágata were not affected.

The efficiency of different estimation methods of hydro-physical limits

The soil water available to crops is defined by specific values of water potential limits. Underlying the estimation of hydro-physical limits, identified as permanent wilting point (PWP) and field capacity (FC), is the selection of a suitable method based on a multi-criteria analysis that is not always clear and defined. In this kind of analysis, the time required for measurements must be taken into consideration as well as other external measurement factors, e.g., the reliability and suitability of the study area, measurement uncertainty, cost, effort and labour invested. In this paper, the efficiency of different methods for determining hydro-physical limits is evaluated by using indices that allow for the calculation of efficiency in terms of effort and cost. The analysis evaluates both direct determination methods (pressure plate - PP and water activity meter - WAM) and indirect estimation methods (pedotransfer functions - PTFs). The PTFs must be validated for the area of interest before use, but the time and cost associated with this validation are not included in the cost of analysis. Compared to the other methods, the combined use of PP and WAM to determine hydro-physical limits differs significantly in time and cost required and quality of information. For direct methods, increasing sample size significantly reduces cost and time. This paper assesses the effectiveness of combining a general analysis based on efficiency indices and more specific analyses based on the different influencing factors, which were considered separately so as not to mask potential benefits or drawbacks that are not evidenced in efficiency estimation.

Optical crop sensor for variable-rate nitrogen fertilization in corn: II - indices of fertilizer efficiency and corn yield

Generally, in tropical and subtropical agroecosystems, the efficiency of nitrogen (N) fertilization is low, inducing a temporal variability of crop yield, economic losses, and environmental impacts. Variable-rate N fertilization (VRF), based on optical spectrometry crop sensors, could increase the N use efficiency (NUE). The objective of this study was to evaluate the corn grain yield and N fertilization efficiency under VRF determined by an optical sensor in comparison to the traditional single-application N fertilization (TSF). With this purpose, three experiments with no-tillage corn were carried out in the 2008/09 and 2010/11 growing seasons on a Hapludox in South Brazil, in a completely randomized design, at three different sites that were analyzed separately. The following crop properties were evaluated: aboveground dry matter production and quantity of N uptake at corn flowering, grain yield, and vegetation index determined by an N-Sensor® ALS optical sensor. Across the sites, the corn N fertilizer had a positive effect on corn N uptake, resulting in increased corn dry matter and grain yield. However, N fertilization induced lower increases of corn grain yield at site 2, where there was a severe drought during the growing period. The VRF defined by the optical crop sensor increased the apparent N recovery (NRE) and agronomic efficiency of N (NAE) compared to the traditional fertilizer strategy. In the average of sites 1 and 3, which were not affected by drought, VRF promoted an increase of 28.0 and 41.3 % in NAE and NRE, respectively. Despite these results, no increases in corn grain yield were observed by the use of VRF compared to TSF.

Efficiency of nitrogen fertilizer applied at corn sowing in contrasting growing seasons in Paraguay

In order to select soil management practices that increase the nitrogen-use efficiency (NUE) in agro-ecosystems, the different indices of agronomic fertilizer efficiency must be evaluated under varied weather conditions. This study assessed the NUE indices in no-till corn in southern Paraguay. Nitrogen fertilizer rates from 0 to 180 kg ha-1 were applied in a single application at corn sowing and the crop response investigated in two growing seasons (2010 and 2011). The experimental design was a randomized block with three replications. Based on the data of grain yield, dry matter, and N uptake, the following fertilizer indices were assessed: agronomic N-use efficiency (ANE), apparent N recovery efficiency (NRE), N physiological efficiency (NPE), partial factor productivity (PFP), and partial nutrient balance (PNB). The weather conditions varied largely during the experimental period; the rainfall distribution was favorable for crop growth in the first season and unfavorable in the second. The PFP and ANE indices, as expected, decreased with increasing N fertilizer rates. A general analysis of the N fertilizer indices in the first season showed that the maximum rate (180 kg ha-1) obtained the highest corn yield and also optimized the efficiency of NPE, NRE and ANE. In the second season, under water stress, the most efficient N fertilizer rate (60 kg ha-1) was three times lower than in the first season, indicating a strong influence of weather conditions on NUE. Considering that weather instability is typical for southern Paraguay, anticipated full N fertilization at corn sowing is not recommended due the temporal variability of the optimum N fertilizer rate needed to achieve high ANE.

Daily intake of lactating crossbred cows grazing elephant grass rotationally

The goal of this trial was to estimate the total dry matter (TDMI) and daily pasture dry matter intakes (PDMI) by lactating crossbred Holstein - Zebu cows grazing elephant grass (Pennisetum purpureum Schum.) paddocks submitted to different rest periods. Three groups of 24 cows were used during two years. The paddocks were grazed during three days at the stocking rate of 4.5 cows/ha. Treatments consisted of resting periods of 30 days without concentrate and resting periods of 30, 37.5 and 45 days with 2 kg/cow/day of 20.6% crude protein concentrate. From July to October, pasture was supplemented with chopped sugarcane plus 1% urea. Total daily dry matter intake was estimated using the extrusa in vitro dry matter digestibility and the fecal output with chromium oxide. Regardless of the treatment the estimated average TDMI was 2.7, 2.9 and 2.9±0.03% and the mean PDMI was 1.9, 2.1 and 2.1±0.03% of body weight in the first, second and third grazing day, respectively (P<0.05). Only during the summer pasture quality was the same whichever the grazing day. Sugarcane effectively replaced grazing pasture, mainly in the first day when pasture dry matter intake was lowest.

Effects of plant population and nitrogen fertilizer on yield and efficiency of maize-bean intercropping

Nitrogen supply and plant population are basic parameters for cereal-legume intercropping. In order to study plant population and nitrogen fertilizer effects on yield and yield efficiency of maize-bean intercropping, a field experiment was established. Three bean plant populations and three nitrogen levels were used. Maize dry matter accumulation decreased with increases in bean plant population. Competitive effect of intercrop beans on maize yields was high at higher plant populations, being decreased by nitrogen fertilizer; application of 50 kg ha-1 N was very efficient in increasing maize cob yield. Intercropping significantly decreased harvest index of beans in all plant population and nitrogen fertilizer situations. The efficiency of intercropping, compared to sole cropping, was evidenced by the values obtained for Land Equivalent Ratio (LER) for biomass, cob and pod yields that increased with increases in bean plant populations and nitrogen fertilizer levels.

Efficiency of five biosolids to supply nitrogen and phosphorus to ryegrass

Biosolids have been considered satisfactory to supply crops and plant nutrients. The ideal biosolids application rate should result in high crop yields and nutrient uptake, and leave low concentrations of nutrients in soils to avoid environmental problems. The objective of this study was to estimate the capacity of five biosolids to supply N and P to ryegrass (Lolium perenne) after a single application of either fertilizers or biosolids to a Spodosol and an Oxisol. Results showed that 6% - 36% of N and 3% - 7% of P applied as biosolids were recovered in plants grown on the Spodosol, while the range on the Oxisol was 26%-75% for N and 1.2%-3.7% for phosphorus. Biosolids' efficiency on supplying N and P to plants was similar to fertilizer on the Spodosol, but on the Oxisol it refrained to 65%-67% fertilizer's efficiency. After a single application of biosolids followed by six consecutive harvests, 25%-94% of the N and 93%-99% of the P were not used by plants and remain in the soils.