Symbioses of Cyanobacteria in Marine Environments: Ecological Insights and Biotechnological Perspectives

Cyanobacteria are a diversified phylum of nitrogen-fixing, photo-oxygenic bacteria able to colonize a wide array of environments. In addition to their fundamental role as diazotrophs, they produce a plethora of bioactive molecules, often as secondary metabolites, exhibiting various biological and ecological functions to be further investigated. Among all the identified species, cyanobacteria are capable to embrace symbiotic relationships in marine environments with organisms such as protozoans, macroalgae, seagrasses, and sponges, up to ascidians and other invertebrates. These symbioses have been demonstrated to dramatically change the cyanobacteria physiology, inducing the production of usually unexpressed bioactive molecules. Indeed, metabolic changes in cyanobacteria engaged in a symbiotic relationship are triggered by an exchange of infochemicals and activate silenced pathways. Drug discovery studies demonstrated that those molecules have interesting biotechnological perspectives. In this review, we explore the cyanobacterial symbioses in marine environments, considering them not only as diazotrophs but taking into consideration exchanges of infochemicals as well and emphasizing both the chemical ecology of relationship and the candidate biotechnological value for pharmaceutical and nutraceutical applications.     

Pool of resistance mechanisms to glyphosate in Digitaria insularis

Digitaria insularis biotypes resistant to glyphosate have been detected in Brazil. Studies were carried out in controlled conditions to determine the role of absorption, translocation, metabolism, and gene mutation as mechanisms of glyphosate resistance in D. insularis. The susceptible biotype absorbed at least 12% more (14)C-glyphosate up to 48 h after treatment (HAT) than resistant biotypes. High differential (14)C-glyphosate translocation was observed at 12 HAT, so that >70% of the absorbed herbicide remained in the treated leaf in resistant biotypes, whereas 42% remained in the susceptible biotype at 96 HAT. Glyphosate was degraded to aminomethylphosphonic acid (AMPA), glyoxylate, and sarcosine by >90% in resistant biotypes, whereas a small amount of herbicide (up to 11%) was degraded by the susceptible biotype up to 168 HAT. Two amino acid changes were found at positions 182 and 310 in EPSPS, consisting of a proline to threonine and a tyrosine to cysteine substitution, respectively, in resistant biotypes. Therefore, absorption, translocation, metabolism, and gene mutation play an important role in the D. insularis glyphosate resistance.     

Antioxidant evaluation in dessert spices compared with common food additives. Influence of irradiation procedure

The antioxidant properties of seven dessert spices (anise, cinnamon, ginger, licorice, mint, nutmeg, and vanilla) were compared with those of the common food antioxidants butylated hydroxyanisole (BHA) (E-320), butylated hydroxytoluene (BHT) (E-321), and propyl gallate (E-310). The influence of irradiation process on antioxidant activity was also evaluated. Mint and cinnamon exhibited a higher percentage of inhibition of oxidation than the other spices analyzed and the food antioxidants, as tested by the lipid peroxidation assay (LOO*). Nutmeg, anise, and licorice showed the strongest protection in the deoxyribose assay (OH*). Vanilla exhibited the highest antioxidant activity in the peroxidase-based assay (H2O2). Nutmeg, propyl gallate, ginger, and licorice improved the stability of oils (sunflower, corn, and olive) and fats (butter and margarine) against oxidation (110 degrees C Rancimat). Cinnamon was a better superoxide radical scavenger than the other analyzed spices and additives. When the Trolox equivalent antioxidant capacity (TEAC) assay was used to provide a ranking order of antioxidant activity, the result in decreasing order of antioxidant capacity was cinnamon approximately equal to propyl gallate > mint > anise > BHA > licorice approximately equal to vanilla > ginger > nutmeg > BHT. Irradiated samples did not show significant differences (p < 0.05) in the antioxidant activity with respect to the non-irradiated samples (1, 3, 5, and 10 kGy) in the assays used.     

Maedi-visna virus infection of ovine mammary epithelial cells

The aim of this work was to perform a complete study of maedi-visna virus (MVV) infected mammary glands of naturally-infected sheep, and to determine if cells other than macrophages undergo a productive viral infection in this organ. Fifteen seropositive and two seronegative ewes were selected from MVV-infected flocks on the basis of clinical indurative mastitis and three sheep from an MVV-free flock. Within the mammary gland, MVV-positive cells were located by immunohistochemistry in the stroma and the epithelial alveolar barrier, most likely the ovine mammary epithelial cells (OMEC) of the acini. In situ hybridization confirmed these findings. Ultrastructural studies showed the presence of lentivirus-like particles budding off the cell surface in the alveolar barrier and also free in the acinar lumen. The presence of mammary histopathological lesions and MVV together with clear indications of productive infection (demonstration of a cytopathic effect in OMEC cultures and infection of co-cultures) were observed in the 15 seropositive and one of the seronegative sheep from the infected flock. These findings demonstrate that the OMEC were infected in vivo and probably underwent productive infection when studied ex-vivo. The OMEC of MVV-free sheep, which had subsequently been infected in vitro with MVV, also showed productive infection when challenged in vitro, confirming the replication of MVV in OMEC in vitro. The presence of MVV-infected OMEC in the mammary gland from infected animals, the productive infection in these OMEC and the release of lentiviral particles to the acinar lumen may have relevance in the pathogenesis and transmission of MVV infection.     

The Use of Positron Emission Tomography in Soft Tissue Sarcoma Patients under Therapy with Trabectedin

Background

We used 2-deoxy-2-[¹⁸F] fluoro-D-glucose (FDG) positron emission tomography (PET) to evaluate the FDG uptake in patients with advanced and/or metastatic soft tissue sarcoma (STS) undergoing therapy with Ecteinascidin-743 (ET-743, Trabectedin, Yondelis™).

Patients and Methods

The pilot study included nine patients with metastatic STS receiving a minimum of one cycle of treatment with trabectedin. Patients were examined using PET prior to onset of therapy and after completion of one or three cycles of trabectedin. Restaging according to Response Evaluation Criteria in Solid Tumours (RECIST) was performed in parallel using computed tomography (CT) and/or magnetic resonance imaging (MRI) and served for reference.

Results

Clinical outcome of nine evaluable patients was as follows: one patient with partial remission (PR), three patients with stable disease (SD), and five patients with progressive disease (PD). A more than 40% decrease of the standardized uptake value (SUV) of sequential PET examination could be demonstrated for the responding patient (PR), whereas patients with SD or PD showed a stable SUV, but no increase in SUV.

Conclusion

To our knowledge, this is the first small series of patients being treated with trabectedin and monitored using sequential PET imaging demonstrating SUV stabilization in nearly all monitored patients.     

Effects of exogenous enzymes,Lactobacillus acidophilus or their combination on feed performance response and carcass characteristics of rabbits fed sugarcane bagasse

The aim of this study was to evaluate the effect of Lactobacillus acidophilus(LAC), exogenous enzymes of ZAD(exogenous enzyme preparation) or their combination on feed conversion, and dressing of rabbits fed different treatments of sugarcane bagasse(SCB). Five rations were allotted randomly to five groups of New-Zealand White(NZW) rabbits(n=10) with initial live body weight of(838±42.4) g and 5 weeks of age. Rabbits were fed on diets with different sources of fiber as follows,(i) a control diet composed of 100% berseem hay and 0% SCB,(ii) 50% berseem hay and 50% untreated SCB(USCB),(iii) 50% berseem hay and 50% SCB treated with L. acidophilus(LAC),(iv) 50% berseem hay and 50% SCB treated with ZAD(ZAD), and(v) 50% berseem hay and 50% SCB treated with a combination of LAC+ZAD(LZ). Treatments of SCB with L. acidophilus, ZAD and LAC+ZAD had the highest feed conversion ratio than both USCB and control. The dressing percentage of rabbits that fed the LAC and LZ diets was higher(P0.05) compared with that in the other groups. Performance index(PI) for LAC group was improved(P0.05) compared to that for the other groups; however, PI for USCB group was the lowest(P0.05). It could be concluded that treating SCB with L. acidophilus, exogenous enzymes of ZAD or their combination improved feed conversion and performance with more positive effects with L. acidophilus than the other treatments.     

Effects of organic chromium supplementation to finishing lambs diet on growth performance,carcass characteristics and meat quality

The objective of this study was to evaluate supplemental organic chromium(Cr) to finishing lambs on growth performance, carcass characteristics, and meat quality. Eighteen Suffolk lambs(age(4.5±0.2) mon;(25.8±3.6) kg body weight(BW)) were randomly assigned to three levels of supplemental organic Cr(0.0, 0.2 and 0.4 mg kg–1 dry matter(DM)) in a complete random design. Growth performance was evaluated for 70 d, and then lambs were slaughtered to study carcass characteristics and chemical composition of meat. Orthogonal contrasts were performed(contrast one-average level 0.2 ppm Cr vs. average level 0.4 ppm Cr; contrast two-level 0 vs. average levels(0.2+0.4) ppm Cr). Orthogonal polynomials were used to estimate the linear and quadratic effects of Cr concentrations. Growth and carcass performance were not affected by supplemental organic Cr. Muscle conformation and leg perimeter linearly increased(P0.05) as organic Cr level increased in the diet. Kidney fat decreased linearly(P0.05) as supplemental Cr increased. In Longissimus dorsi(LD), the ash content decreased linearly, and shear force(kg cm–2) increased(P0.05) as organic Cr level increased in the diet. It is concluded that organic Cr did not affect growth performance, but it improved positively the muscle conformation, reduced kidney fat, whereas in LD there was an increment in shear force in finishing carcass lambs.