Interaction of Collimonas strain IS343 with Rhizoctonia solani at low carbon availability in vitro and in soil

Collimonas sp. IS343, isolated from an organically-farmed arable soil and characterized as a broad-range oligotrophic bacterium, was shown to degrade chitin and to suppress R. solani mycelium growth under in vitro conditions at high and low carbon availabilities. In contrast to C. fungivorans Ter331, strain IS343 did not respond with an increase in growth rate to higher carbon levels in liquid medium, it reached higher cell numbers in carbon-poor media and it showed better survival in bulk soil. Therefore, it was concluded that strain IS343 cells are better adapted to circumstances of low carbon availability as present in bulk soils than strain Ter331 cells. Further, strain IS343 cells were more suppressive towards R. solani than strain Ter331 cells in vitro. When introduced into soil, strain IS343 cells delayed disease development caused by R. solani AG2-2IIIB in sugar beet plants. These results suggest that strain IS343 cells are able to tentatively suppress R. solani AG2-2IIIB mycelium growth in soil. Potential mechanisms behind the observed suppressive effects can be competition for available nutrients between strain IS343 cells and R. solani mycelium in soil or the production of chitinase as shown for this and other Collimonas species.     

Physico‐chemical characterization of humic‐metal‐phosphate complexes and their potential application to the manufacture of new types of phosphate‐based fertilizers

The aim of this review is to describe the main physicochemical characteristics of diverse types of humic‐metal‐phosphate acid complexes. The effects of these complexes on phosphorus (P) fixation in soils with different pH values and physicochemical features and on plant phosphorus uptake are also discussed. Humic‐metal‐phosphate complexes have apparent stability constants in the same range as those of metal‐humic complexes, in solutions with diverse pH and ionic‐strength values. Likewise, the molecular‐size distribution of humic‐metal‐phosphate complexes as a function of pH is similar to that of potassium or sodium humates and metal‐humic complexes. Humic‐metal‐phosphate complexes are able to decrease phosphate fixation in soils and increase plant growth and phosphate uptake. Phosphorus fertilizers containing humic‐metal‐phosphate complexes proved to be efficient to improve plant growth and P uptake with respect to conventional fertilizers such as single superphosphate. The values of parameters related to plant phosphorus‐utilization efficiency (PUt E) suggest that the regulation of root acquisition of phosphate from these complexes could involve the interregulation of a system for the optimization of metabolic P utilization in the shoot and another system involving stress responses of roots under phosphorus deficiency.     

Use of a graft of demineralized bone matrix along with TGF-β1 leads to an early bone repair in dogs

Tibia fractures are common in small animal practice. Over the past decade, improvements to animal internal fracture fixation have been developed. TGF-β1 has been shown to be crucial in the development, induction and repair of bone. In present study, we investigate the effect of local application of a graft demineralized bone matrix (DBM) along with TGF-β1 in a model of open osteotomy induced experimentally in dogs. Tibia fracture was brought about by using an open osteotomy model in young male dogs. Fracture repair was evaluated by a histological and biochemical analysis. Collagen content, proteolytic activity and urokinase-type plasminogen activator (uPA) expression were analyzed at the end of the study. Radiographic analysis, alkaline phosphatase and hematological evaluation were performed weekly. At the fifth week, there was an improvement and restoration of bone architecture in animals treated with a graft containing TGF-β1 (5 ng/ml) compared with the control and graft groups, as was evidenced by the presence of an early formation of wide callus and bone regeneration. In addition, local application of TGF-β1 led to an increase in collagen and proteolytic activity. More immunopositive osteoclast and mesenchymal cells were found in bone tissue from animals treated with TGF-β1 as compared with the control group. No changes in alkaline phosphatase, hematological and clinical parameters were observed. This study shows that the combined use of DBM along with TGF-β1 is able to improve and accelerate the bone repair.     

Length of productive life of sows in four pig farms in the tropics of Mexico

The objective of this study was to determine the effect of some factors on the length of productive life (LPL), the number of parities (NP), and the culling interval (CI) of sows. The information from 2003 to 2009 of 3,746 sows with LPL and NP records and 5,819 sows with CI records from the four farms of Yucatan, Mexico was used. LPL was defined as the number of days between the first farrowing and culling or death and CI as the number of days between the last farrowing and culling. To determine the effects of farm, litter size at first farrowing (LSF1) and age at first farrowing (AF1) on LPL and NP, and of farm, LSF1 and culling reason on CI general linear models were used. Means and standard errors for LPL, NP, and CI were 496.4 ± 8.42 days, 3.35 ± 0.04 parities, and 48.3 ± 0.52 days, respectively. All factors had significant effects (P < 0.05) on LPL, NP, and CI. The sows from farm 2 stayed longer (806.0 days) and had more parities (5.25) than the sows from the other farms. Sows with the smallest litters (≤8 piglets) at first farrowing stayed the least time in the farm (675.1 days) and had the fewest parities (4.49). Gilts farrowing the first time before 331 days of age stayed longer time in the farm (726.4 days) and had more parities (4.81) in comparison with 331–348 and more than 348 days age groups. With respect to CI, the sows in farm 3 stayed the longest time in the farm. Sows with more than five parities were culled sooner after their last farrowing. In conclusion, differences between farms for LPL, PN, and CI were found. Females that farrowed at a short age and those with large litters stayed longer in the herd. Old sows and those culled for reproductive reasons stayed the least time in the herd after their last farrowing.     

Genetic diversity in seven populations of Nicaraguan teosinte (<Emphasis Type="Italic">Zea nicaraguensis</Emphasis> Iltis et Benz) as estimated by microsatellite variation

Teosintes are the closest relatives to modern maize, Zea mays L. ssp. mays. They are wild grasses with a native distribution area from Mexico to Nicaragua and represent an important genetic resource. However, the genetic diversity of Nicaraguan teosinte (Zea nicaraguensis Iltis et Benz) has not yet been determined. This teosinte species has decreased in the last 25 years and now must be regarded as an endangered species. An analysis of the genetic diversity of Zea nicaraguensis was carried out in a total of 240 individuals from seven populations. Eleven Simple Sequences Repeat (SSR) primer pairs were used. A total of 42 alleles were found, the range of alleles per locus was 2–5 (mean 3.8) and the numbers of genotypes varied between primers. The primer Bnlg 1538 showed the highest value, with 45 genotypes through all populations. The genetic diversity observed (Ho) between all populations varied from 0.51 to 0.63, with an average of 0.563. One of the populations had as many as 40 alleles. Analysis of molecular variance (AMOVA) revealed that most of the variation was within population, at a significantly high level (P < 0.001). Rare alleles were detected in all populations, but unique alleles were only found in four populations. These results are highly relevant when developing conservation strategies and show that preserving populations in their natural habits is highly important.     

Cell viability effects and antioxidant and antimicrobial activities of Tunisian date syrup (Rub El Tamer) polyphenolic extracts

The aqueous-acetone polyphenolic extract of the traditionally derived date syrup, known as "Rub El Tamer", was analyzed using RP-HPLC-DAD and ESI-MS. The phenolic content of the extract was 394.53 ± 1.13 mg per 100 g of syrup with caffeoylsinapylquinic acid as the most abundant compound (72.23%). The extract exhibited strong antioxidant activities as evaluated using the ABTS (2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)), DPPH (2,2-diphenyl-1-picrylhydrazyl) and FRAP (ferric reducing antioxidant power) methods. The extract antimicrobial potential against a range of microorganism strains showed that Staphylococcus aureus, Staphylococcus epidermidis, and Bacillus cereus were the most sensitive bacteria with MBC in the range of 0.5-0.05 mg/mL. Furthermore, in the presence of the syrup extract (8.18-131 μg/mL), the Human SH-SY5Y neuroblastoma and the 3T3 fibroblast cell lines showed dissimilar reduction of viability suggesting a higher cytotoxic effect against tumorigenic cells. Our results provide new insights into date syrup characterization which should stimulate further studies of this hot desert resource.     

Morphophysiology of forage peanut submitted to different intensities of defoliation on grazing with sheep

Tropical Animal Health and Production - The aim was to monitor the growth, the dry mass accumulation curve, and the structural photosynthetic components of forage peanut pasture, in different...