Improvement in cyst recovery and molecular detection of Giardia duodenalis from stool samples

Molecular Biology Reports - Molecular detection of Giardia duodenalis by polymerase chain reaction (PCR) is difficult in faecal samples due to inhibitors that contaminate DNA preparations, or due...     

Highways are a threat for giant armadillos that underpasses can mitigate

We report 24 records of giant armadillo roadkill on Brazilian highways in the Cerrado, Pantanal and Amazon biomes illustrating that highways are a threat to this species. However, we also documented the species using underpasses, demonstrating that these structures could help to reduce the risk of roadkill for giant armadillos.     

Lateral position preference in grazing feral horses

Behavioural lateralisation is an effective way for animals to manage daily tasks by specialising behaviour to either side of the body. Many types of lateralisation are linked to the function of each brain hemisphere. Lateralisation of monitoring behaviour in mother–infant relationships occurs in a wide range of mammals, where infants frequently use their left eye to monitor their mother. However, few studies have focused on this type of spatial relationships among adults in daily life, such as during foraging. The present study focused on monitoring adult feral horse behaviour using quantitative analysis of spatial relationships, using drone technology. We found that horses form a localised spatial relationship with their nearest neighbour. Specifically, the nearest neighbour was located to the left rear of a target individual significantly more frequently than to the right rear. Furthermore, the nearest neighbour was less frequently located behind a target individual. We propose that this relationship is caused by a left-eye preference, because information via the left eye predominantly proceeds to the right hemisphere, which is dominant for social processing.     

Integrin participates in the effect of thyroxine on plasma membrane in immature rat testis

Background

The secretory activity of Sertoli cells (SC) is dependent on ion channel functions and protein synthesis and is critical to ongoing spermatogenesis. The aim of this study was to investigate the mechanism of action associated with a non-metabolizable amino acid [¹⁴C]-MeAIB (α-(methyl-amino)isobutyric acid) accumulation stimulated by T₄ and the role of the integrin receptor in this event, and also to clarify whether the T₄ effect on MeAIB accumulation and on Ca²⁺ influx culminates in cell secretion.

Methods

We have studied the rapid and plasma membrane initiated effects of T₄ by using ⁴⁵Ca²⁺ uptake and [⁴⁵C]-MeAIB accumulation assays, respectively. Thymidine incorporation into DNA was used to monitor nuclear activity and quinacrine to analyze the secretory activity on SC.

Results

The stimulation of MeAIB accumulation by T₄ appears to be mediated by the integrin receptor in the plasma membrane since tetrac and RGD peptide were able to nullify the effect of this hormone. In addition, T₄ increases extracellular Ca²⁺ uptake and Ca²⁺ from intracellular stocks to enhance nuclear activity, but this genomic action seems not to influence SC secretion mediated by T₄. Also, the cytoskeleton and ClC-3 chloride channel contribute to the membrane-associated responses of SC.

Conclusions

T₄ integrin receptor activation ultimately determines the plasma membrane responses on amino acid transport in SC, but it is not involved in calcium influx, cell secretion or the nuclear effect of the hormone.

General significance

The integrin receptor activation by T₄ may take a role in plasma membrane processes involved in the male reproductive system.     

Effect of Acute Administration of l-Tyrosine on Oxidative Stress Parameters in Brain of Young Rats

Tyrosinemia type II, also known as Richner–Hanhart syndrome, is an autosomal recessive inborn error of metabolism caused by a deficiency of hepatic cytosolic tyrosine aminotransferase, and is associated with neurologic and development difficulties in numerous patients. Considering that the mechanisms underlying the neurological dysfunction in hypertyrosinemic patients are poorly known and that studies demonstrated that high concentrations of tyrosine provoke oxidative stress in vitro and in vivo in the cerebral cortex of rats, in the present study we investigate the oxidative stress parameters (enzymatic antioxidant defenses, thiobarbituric acid-reactive substances and protein carbonyl content) in cerebellum, hippocampus and striatum of 30-old-day rats after acute administration of l-tyrosine. Our results demonstrated that the acute administration of l-tyrosine increased the thiobarbituric acid reactive species levels in hippocampus and the carbonyl levels in cerebellum, hippocampus and striatum. In addition, acute administration of l-tyrosine significantly decreased superoxide dismutase activity in cerebellum, hippocampus and striatum, while catalase was increased in striatum. In conclusion, the oxidative stress may contribute, along with other mechanisms, to the neurological dysfunction characteristic of hypertyrosinemia and the administration of antioxidants may be considered as a potential adjuvant therapy for tyrosinemia, especially type II.     

Diplospory and obligate apomixis in Miconia albicans (Miconieae, Melastomataceae) and an embryological comparison with its sexual congener M. chamissois

Apomixis, or asexual reproduction through seeds, has been reported for species of the tribe Miconieae, Melastomataceae, but details of the process have yet to be described. We analyzed and compared sporogenesis and gametogenesis in the apomictic Miconia albicans and the sexual M. chamissois. The results point to some differences between species, which were related to the apomictic process. In M. albicans microsporogenesis, problems during meiosis and degeneration of its products led to total pollen sterility, while M. chamissois presented normal bicellular pollen grains in the mature anther. The absence or abnormality of meiosis in M. albicans megasporogenesis led to the formation of an unreduced embryo sac and also to egg cell parthenogenesis, which gave rise to the apomictic embryo. Embryo and endosperm development were autonomous, resulting in seeds and fruits independent of pollination and fertilization. Thus, in this species, apomixis can be classified as diplosporic and obligate. In contrast, meiosis was as expected in the sexual M. chamissois, and led to the development of a reduced embryo sac. Despite the divergent pathways, many embryological characteristics were similar between the studied species and other Melastomataceae and they seem to be conservative character states for the family.     

Antimicrobial effects of terpinen-4-ol against oral pathogens and its capacity for the modulation of gene expression

Abstract

This study evaluated the antibacterial activity of terpinen-4-ol against Streptococcus mutans and Lactobacillus acidophilus and its influence on gbpA (S. mutans) and slpA (L. acidophilus) gene expression. As measured by XTT assay, the concentrations of terpinen-4-ol that effectively inhibited the biofilm were 0.24% and 0.95% for S. mutans and L. acidophilus, respectively. Confocal microscopy revealed the presence of a biofilm attached to the enamel and dentin block surfaces with significant terpinen-4-ol effects against these microorganisms. The expression of the gbpA and slpA genes involved in adherence and biofilm formation was investigated using RT-PCR. Expression of these genes decreased after 15?min with 0.24% and 0.95% terpinen-4-ol in S. mutans and L. acidophilus, respectively. These findings demonstrate the antimicrobial activity of terpinen-4-ol and its ability to modulate the expression of gbpA and slpA genes, emphasizing the therapeutic capacity of terpinen-4-ol as an alternative to inhibit adherence in biofilm.     

Flow cytometry and live confocal analysis for the evaluation of the uptake and intracellular distribution of FITC-ODN into HaCaT cells

In this study, the mechanism of the internalization and the cellular distribution of 59 fluorescein conjugated PS-ODN (FITC-ODN) after transfection with different mixed lipidic vesicles/oligo complexes (lipoplexes) have been investigated. Mixed lipidic vesicles were prepared with one of the most used cationic lipid (DOTAP) and different amounts of a cholic acid (UDCA) to release the oligo into HaCaT cells. Using flow cytometry, the cellular uptake of the oligo was studied with and without different inhibitors able to block selectively the different pathways involved in the internalization mechanism. The intracellular distribution of the oligo was analyzed by confocal laser scanning microscopy (CLSM), treating the cells with the lipoplexes and directly observing without any fixing procedure. To better carry out the colocalization studies, fluorescent-labeled markers, specific for the different cellular compartments, were coincubated with 59 fluorescein-conjugated 29-mer phosphorotioate oligonucleotide (FITC-ODN). The different lipidic vesicles affect the internalization mechanism of FITC-ODN. After using the inhibitors, the uptake of complexes involved a different internalization mechanism. The live CLSM analysis demonstrated that, after 1 hour from the complex incubation, the oligo was transferred into cells and localized into the endosomes; after 24 hours, the oligo was intracellularly localized close to the nuclear structure in a punctuate pattern. However, the results from fusion experiments showed also a binding of a quite low amount of oligo with the cell membranes.