Studies on PVP hydrogel-supported luminol chemiluminescence: 2. Luminometer calibration and potential analytical applications.

The use of poly(N-vinyl-2-pyrrolidone) (PVP) hydrogel-supported luminol chemiluminescence (CL) for the automatic determination of hydrogen peroxide and the quantification of the antiradical capacity of Trolox is described. The hydrogel containing luminol and hemin is prepared directly on a 96-well microplate and can be stored for up to 3 months without significant decrease in CL quantum yields. Furthermore, this system can also be used as a secondary light standard for the calibration of microplate luminometers.     

In vivo and in silico anti-inflammatory mechanism of action of the semisynthetic (−)-cubebin derivatives (−)-hinokinin and (−)-O-benzylcubebin

(?)-Cubebin (CUB), isolated from seeds of Piper cubeba, was used as starting material to obtain the derivatives (?)-hinokinin (HK) and (?)-O-benzyl cubebin (OBZ). Using paw edema as the experimental model and different chemical mediators (prostaglandin and dextran), it was observed that both derivatives were active in comparison with both negative (5% Tween® 80 in saline) and positive (indomethacin) controls. The highest reduction in the prostaglandin-induced edema was achieved by OBZ (66.0%), while HK caused a 59.2% reduction. Nonetheless, the dextran-induced paw edema was not significantly reduced by either of the derivatives (HK or OBZ), which inhibited edema formation by 18.3% and 3.5%, respectively, in contrast with the positive control, cyproheptadine, which reduced the edema by 56.0%. The docking analysis showed that OBZ presented the most stable ligand-receptor (COX-2 – cyclooxygenase-2) interaction in comparison with CUB and HK.     

Inter‐ and intraspecific variability in physiological traits and post‐anoxia recovery of photosynthetic efficiency in grasses under oxygen deprivation

Low oxygen conditions occur in grass sites due to high and frequent precipitation, poor soil quality, and over‐irrigation followed by slow drainage. Three warm‐season and one cool‐season grass were analyzed at metabolic level during a time‐course experiment performed in a controlled anoxic environment. Prolonged oxygen depletion proved detrimental by leading to premature death to all the species, with the exception of seashore paspalum. Moreover, the anoxia tolerance observed in these grasses has been associated with slow use of carbohydrates, rather than with their relative abundance, which was more important than their antioxidant capacity. Further physiological characterization of eight seashore paspalum genotypes to anoxia was also performed, by examining the variation in photosystem II (PSII) efficiency and gas exchange during post‐anoxia recovery. Multivariate analysis highlighted the presence of three main clusters of seashore paspalum genotypes, characterized by different ability to restore the PSII photochemistry during recovery after one day of anoxia. Taken together, our data demonstrate that the analysis of post‐anoxia recovery of fluorescence and gas exchange parameters can represent a fast and reliable indicator for selecting species and cultivars more able to acclimate their photosynthetic apparatus.     

Trypanoxyuris (Trypanoxyuris) minutus (Schneider, 1866) among Alouatta guariba clamitans (Cabrera, 1940) in the state of Rio de Janeiro,Brazil

This study reports on infection by Trypanoxyuris (Trypanoxyuris) minutus among Alouatta guariba clamitans through biometry on adults and eggs. A total of 58 adult helminths were recovered from the small segment of the animal's large intestine. This study is the first report of this parasite among A. guariba clamitans in Rio de Janeiro.     

Influence of culture conditions on mycelial growth and bioluminescence of Gerronema viridilucens

Herein we describe a procedure for measuring the total light emission of the naturally bioluminescent tropical fungus Gerronema viridilucens and the optimization of culture conditions using multivariate factorial anova. Cultures growing on an agar surface in 35 mm Petri dishes at 90% humidity show optimal bioluminescence emission at 25 degrees C in the presence of 1.0% sugar cane molasses, 0.10% yeast extract and pH 6.0 (nonbuffered). Temperature and pH are the most important factors for both mycelial growth and bioluminescence.     

Bactericidal activity of LFchimera is stronger and less sensitive to ionic strength than its constituent lactoferricin and lactoferrampin peptides

The innate immunity factor lactoferrin harbours two antimicrobial moieties, lactoferricin and lactoferrampin, situated in close proximity in the N1 domain of the molecule. Most likely they cooperate in many of the beneficial activities of lactoferrin. To investigate whether chimerization of both peptides forms a functional unit we designed a chimerical structure containing lactoferricin amino acids 17-30 and lactoferrampin amino acids 265-284. The bactericidal activity of this LFchimera was found to be drastically stronger than that of the constituent peptides, as was demonstrated by the need for lower dose, shorter incubation time and less ionic strength dependency. Likewise, strongly enhanced interaction with negatively charged model membranes was found for the LFchimera relative to the constituent peptides. Thus, chimerization of the two antimicrobial peptides resembling their structural orientation in the native molecule strikingly improves their biological activity.     

Trametes versicolor: Potential for atrazine bioremediation in calcareous clay soil,under low water availability conditions

This study examined the feasibility of Trametes versicolor to actively degrade atrazine (0.5 μg g^?1) in non-sterile calcareous clay soil (Algarve, Portugal) microcosms for up to 24 weeks (20 °C), under low water availability (soil water potentials of ?0.7 and ?2.8 MPa). Soil respiration, laccase activity, and atrazine quantification by high-performance liquid chromatography (HPLC) were assessed. Respiration was significantly (p < 0.05) enhanced in soil containing the inoculant, particularly in the presence of atrazine, indicating that it remained metabolically active throughout the study. Furthermore, up to 98% and 85% (at ?0.7 and ?2.8 MPa, respectively) of atrazine was degraded in soil containing both the atrazine and the inoculant, compared to 96% and 50% in soil containing atrazine only. The contribution of T. versicolor to atrazine degradation was only significant (p < 0.005) under the driest soil treatment conditions. The strategies used for enhancing colonisation and biodegradation capabilities of the inoculant, as well as the selection of sawdust as carrier, were thus effective. However, there were no differences (p > 0.05) in quantified laccase activity in soil containing the inoculant and the control. Overall, this study demonstrated that T. versicolor was a strong candidate for atrazine bioremediation in soil with low moisture and organic matter contents, such as that found in semi-arid and Mediterranean-like ecosystems.     

V H-ATPase along the yeast secretory pathway: Energization of the ER and Golgi membranes

H⁺ transport driven by V H⁺-ATPase was found in membrane fractions enriched with ER/PM and Golgi/Golgi-like membranes of Saccharomyces cerevisiae efficiently purified in sucrose density gradient from the vacuolar membranes according to the determination of the respective markers including vacuolar Ca²⁺-ATPase, Pmc1::HA. Purification of ER from PM by a removal of PM modified with concanavalin A reduced H⁺ transport activity of P H⁺-ATPase by more than 75% while that of V H⁺-ATPase remained unchanged. ER H⁺ ATPase exhibits higher resistance to bafilomycin (I₅₀ = 38.4 nM) than Golgi and vacuole pumps (I₅₀ = 0.18 nM). The ratio between a coupling efficiency of the pumps in ER, membranes heavier than ER, vacuoles and Golgi is 1.0, 2.1, 8.5 and 14 with the highest coupling in the Golgi. The comparative analysis of the initial velocities of H⁺ transport mediated by V H⁺-ATPases in the ER, Golgi and vacuole membrane vesicles, and immunoreactivity of the catalytic subunit A and regulatory subunit B further supported the conclusion that V H⁺-ATPase is the intrinsic enzyme of the yeast ER and Golgi and likely presented by distinct forms and/or selectively regulated.