Differential effects of coinoculations with Pseudomonas jessenii PS06 (a phosphate-solubilizing bacterium) and Mesorhizobium ciceri C-2/2 strains on the growth and seed yield of chickpea under greenhouse and field conditions

In the course of a project carried out in two regions of Spain, Castilla y León and Andalucía, aiming to find useful biofertilizers for staple grain-legumes, an efficient rhizobia nodulating chickpea (termed as C-2/2) and a powerful in vitro phosphate-solubilizing bacterial strain (termed as PS06) were isolated. Analyses of their 16S rDNA sequence indicated that they belong to the bacterial species Mesorhizobium ciceri and Pseudomonas jessenii, respectively. Greenhouse and field experiments were carried out in order to test the effect of single and dual inoculations on chickpea (ecotype ILC-482) growth. Under greenhouse conditions, plants inoculated with Mesorhizobium ciceri C-2/2 alone had the highest shoot dry weight. The inoculation treatment with P. jessenii PS06 yielded a shoot dry weight 14% greater than the uninoculated control treatment, but it was not correlated with shoot P contents. However, the co-inoculation of C-2/2 with PS06 resulted in a decrease in shoot dry weight with respect to the inoculation with C-2/2 alone. Under field conditions, plants inoculated with M. ciceri C-2/2, in single or dual inoculation, produced higher nodule fresh weight, nodule number and shoot N content than the other treatments. Inoculation with P. jessenii PS06 had no significant effect on plant growth. However, the co-inoculation treatment ranked the highest in seed yield (52% greater than the uninoculated control treatment) and nodule fresh weight. These data suggest that P. jessenii PS06 can act synergistically with M. ciceri C-2/2 in promoting chickpea growth. The contrasting results obtained between greenhouse and field experiments are discussed.     

Additional data in support of the quadruplicated white-ivory reversion system to test for somatic genotoxicity in Drosophila melanogaster.

Cyclophosphamide, ethyl methanesulfonate, propyleneimine and tritiated water were tested in a new short-term somatic mutation bioassay, previously described by Green and coworkers (1986), to evaluate the suitability of the quadruplicated white-ivory system of Drosophila melanogaster for genotoxicity testing of chemicals. A 2.9-kb tandemly duplicated sequence of w+ within a w+ gene is responsible for the white-ivory phenotype. Reversion of wi to w+ is, in general, associated with the loss of the appended 2.9 kb or other alterations affecting this duplicated region. The appearance of light (white or nearly white) phenotypes could be due to the loss of some wi copies. Thus, in the eyes of adult males resulting from treated larvae, we can detect 2 types of sectors (red and light) on the orange-yellow background. Our results indicate that the genetic system used in this somatic assay is sensitive to the genotoxic effects of the 4 compounds tested. All 4 compounds tested were positive. Tritiated water had weak effects, cyclophosphamide was characterized by small revertant clones and ethyl methanesulfonate and propyleneimine by large clone size. From the available data, we feel that the wi system can be considered of potential value for genotoxicity testing.     

Gamete Therapeutics: Recombinant Protein Adsorption by Sperm for Increasing Fertility via Artificial Insemination

A decrease in fertility can have a negative economic impact, both locally and over a broader geographical scope, and this is especially the case with regard to the cattle industry. Therefore, much interest exists in evaluating proteins that might be able to increase the fertility of sperm. Heparin binding proteins (HBPs), specifically the fertility associated antigen (FAA) and the Type-2 tissue inhibitor of metalloproteinase (TIMP-2), act to favor the capacitation and acrosome reaction and perhaps even modulate the immune system’s response toward the sperm. The objective of this research was to determine the effect on fertility of adding recombinant FAA (rFAA) and recombinant TIMP-2 (rTIMP-2) to bovine semen before cryopreservation for use in an artificial insemination (AI) program in a tropical environment. For this experiment, 100 crossbred (Bos taurus x Bos indicus) heifers were selected based on their estrus cycle, body condition score (BCS), of 4 to 6 on a scale of 1 to 9, and adequate anatomical conformation evaluated by pelvic and genital (normal) measurements. Heifers were synchronized using estradiol benzoate (EB), Celosil® (PGF2α) (Shering-Plough) and a controlled internal drug release (CIDR) device was inserted that contained progesterone. Inseminations were performed in two groups at random, 50 animals per group. The control group was inseminated with conventional semen. The treatment group was inseminated with semen containing rFAA (25 µg/mL) and rTIMP-2 (25 µg/mL). In the control group a 16% pregnancy rate was obtained versus a 40% pregnancy rate for the HBP treatment group, resulting in a significant difference (P = 0.0037). Given the results herein, one may conclude that the HBPs can increase fertility and could be an option for cattle in tropical conditions; however, one needs to consider the environment, nutrition, and the genetic interaction affecting the final result in whatever reproductive program that is implemented.     

Kinetic Modelling of in Vitro Lipid Peroxidation Experiments - 'Low Level' Validation of a Model of in Vivo Lipid Peroxidation

Kinetic modelling overcomes some of the drawbacks of purely intuitive thinking in integrating information accumulated on chemical reactions involved in oxidative stress. However, it is important to assess if current knowledge about the reactions that mediate lipid peroxidation already allows satisfactory modelling of this process in near-to-physiological conditions. In this paper, a set of increasingly complex in vitro experiments on antioxidants (a-tocopherol and ascorbate) and lipid peroxidation in heterogeneous systems is simulated. Quantitative to semiquantitative agreement is found between experimental and simulation results. In addition, this theoretical analysis provided useful insights, suggested new hypotheses and experiments and pointed out relevant aspects needing further research. The results encourage and serve as partial validation for the formulation of relatively detailed mathematical models of in vivo lipid peroxidation. Some important aspects of the formulation and analysis of such models are discussed.     

Visualization of R-bands in human metaphase chromosomes by the restriction endonuclease MseI

Human metaphase chromosomes were treated with the restriction endonuclease MseI, which cuts DNA at TTAA sequences. This enzyme preferentially cuts and extracts DNA from G-bands and thus is the first restriction endonuclease allowing direct R-band visualization. Specific patterns ranging from R+C-like to C-like banding can be induced, depending on the concentration of the enzyme. At intermediate concentrations, only a subset of R-bands are produced, corresponding to GC-rich bands that are especially resistant to heat denaturation (so-called T-bands). These results suggest that compositional differences between chromosomal regions determine the different rates of cleavage by MseI, not only between R- and G-bands but also among different R-bands.