Effects of temperature on sperm motility of burbot Lota lota: spontaneous activation and calcium dependency

Several factors regulating activation of spermatozoon motility in Eurasian burbot, Lota lota, including osmolality, calcium (Ca²⁺) ions, and temperature were investigated. Spermatozoon motility in Eurasian burbot, Lota lota was assessed at 4 and 30°C in seminal fluid, isotonic media (with and without Ca²⁺) and hypotonic media (with and without Ca²⁺). Spermatozoa were spontaneously activated in seminal fluid at 20°C and the maximum motility was recorded at 30°C, which is out of the spawning temperature range, indicating that no risk of activation occurs during routine semen handling in artificial insemination. Initiation of spermatozoon motility in L. lota is mediated by Ca²⁺ and sensitivity to Ca²⁺ is dependent on temperature.     

Impaired spermatogenesis associated with changes in spatial arrangement of Sertoli and spermatogonial cells following induced diabetes

The current study was conducted to assess the relationship between testicular cells in spermatogenesis, through which the production of healthy and mature sperm is essential. However, it seems necessary to obtain more information about the three-dimensional pattern of the testis cells arrangement, which is directly related to the function of the testis after induction of diabetes. Twelve adult mice (28-30 g) were assigned into two experimental groups: (1) control and (2) diabetic (40 mg/kg STZ). The epididymal sperm collected from the tail of the epididymis and testes samples were taken for stereology, immunocytochemistry and RNA extraction. Our data showed that diabetes could notably decrease the number of testicular cells, together with a reduction of total sperm count. In addition, the results from the second-order stereology indicated the significant changes in the spatial arrangement of Sertoli cells and spermatogonial cells in the diabetic groups, in comparison with the control (P < .05). Moreover, the immunohistochemistry results showed a significant reduction in Sex-determining Region Y (SRY) box 9 gene (SOX9), vimentin, occludin, and connexin-43 positive cells in the diabetic groups compared with the control (P < .05). Furthermore, our data showed that the expression of steroidogenic acute regulatory protein steroidogenic acute regulatory protein (StAR) and peripheral benzodiazepine receptor peripheral benzodiazepine receptor (PBR) was significantly reduced in the diabetic groups, in comparison with the control (P < .05). These findings suggest that structural and functional changes of testis cells after induction of diabetes cause the alterations in the spatial arrangement of Sertoli and spermatogonial cells, ultimately influencing the normal spermatogenesis in mice.     

Genetic structure of Chrysanthemum genotypes from Iran assessed by AFLP markers and phenotypic traits

Chrysanthemum is popular worldwide as cut flower, potted plant and perennial garden plant. This study used amplified fragment length polymorphism and phenotypic traits to assess genetic diversity and population structure in Chrysanthemum. Results for the phenotypic traits of ray floret number, tubular floret number, flower number, pedicel length, leaflet number on pedicel and days to visible flower bud had high level (i.e., >30 %) evaluations for genotypic coefficient of variation and phenotypic coefficient of variation; thus, heritability for various phenotypic traits ranged from 45.30 to 94.55 %. Phenotypic data clustered the genotypes into four separate groups. Twenty-five primer combinations were used for molecular analysis. On average, each primer combination produced 83.96 polymorphic DNA bands, ranging from 33 to 122 bands. Polymorphic percentage (99.3 %), polymorphism information content (0.43) and Shannon’s information index (0.45) evaluated high levels of genetic variation in the tested genotypes. The Neighbor-Joining (NJ) method grouped genotypes into six clusters, which were in part confirmed by principal coordinate analysis. A Bayesian structure analysis identified four clusters, in which 30 individuals were maintained within the admixed clusters. Results from this study provide appropriate information applicable to designing effective breeding programs and other analyses associated with future studies of Chrysanthemum.     

In vitro study on the alterations of brain tubulin structure and assembly affected by magnetite nanoparticles

In recent decades, considerable efforts have been made to understand the mechanism of memory, cognition, and relevant neurodegenerative diseases in the human brain. Several studies have shown the importance of microtubule proteins in the memory mechanism and memory dysfunction. Microtubules possess dynamicity, which is essential for functions of neuronal networks. Microtubule-associated proteins, i.e., tau, play vital roles in microtubule stability. On the other hand, the ferromagnetic mineral magnetite (Fe₃O₄) has been detected in the normal human brain, and elevated levels of magnetite are also observed in the brains of Alzheimer’s disease patients. Therefore, we propose that a relationship between microtubule organization in axons and brain magnetite nanoparticles is possible. In this study we found alterations of microtubule polymerization in the presence of increasing concentrations of magnetite through transmission electron microscopy images and a turbidimetry method. Structural changes of microtubule and tau protein, as an essential microtubule-associated protein for tubulin assembly, were detected via circular dichroism spectroscopy, intrinsic fluorescence, and 8-anilino-1-naphthalenesulfonic acid fluorometry. We predicted three possible binding sites on tau protein and one possible binding site on tubulin dimer for magnetite nanoparticles. Magnetite also causes the morphology of PC12 cells to change abnormally and cell viability to decrease. Finally, we suggest that magnetite changes microtubule dynamics and polymerization through two paths: (1) changing the secondary and tertiary structure of tubulin and (2) binding to either tubulin dimer or tau protein and preventing tau–tubulin interaction.     

Up-regulated Dicer expression in patients with cutaneous melanoma

Background

MicroRNAs (miRNAs) are small non-coding RNAs (18–24 nucleotides) that have recently been shown to regulate gene expression during cancer progression. Dicer, a central enzyme in the multi-component miRNA biogenesis pathway, is involved in cutting precursor miRNAs to functionally mature forms. Emerging evidence shows that Dicer expression is deregulated in some human malignancies and it correlates with tumor progression, yet this role has not yet been investigated in skin cancers.

Methods and Findings

Using an anti-human monoclonal antibody against Dicer and immunohistochemistry, we compared the expression of Dicer protein among 404 clinically annotated controls and skin tumors consisting of melanocytic nevi (n = 71), a variety of melanomas (n = 223), carcinomas (n = 73) and sarcomas (n = 12). Results showed a cell-specific up-regulated Dicer in 81% of cutaneous, 80% of acrolentiginous and 96% of metastatic melanoma specimens compared to carcinoma or sarcoma specimens (P<0.0001). The expression of Dicer was significantly higher in melanomas compared to benign melanocytic nevi (P<0.0001). In patients with cutaneous melanomas, Dicer up-regulation was found to be significantly associated with an increased tumor mitotic index (P = 0.04), Breslow''s depth of invasion (P = 0.03), nodal metastasis (P = 0.04) and a higher American Joint Committee on Caner (AJCC) clinical stage (P = 0.009). Using western blot analysis, we confirmed the cell-specific up-regulation of Dicer protein in vitro. A pooled-analysis on mRNA profiling in cutaneous tumors showed up-regulation of Dicer at the RNA level in cutaneous melanoma, also showing deregulation of other enzymes that participate in the biogenesis and maturation of canonical miRNAs.

Conclusions

Increased Dicer expression may be a clinically useful biomarker for patients with cutaneous melanoma. Understanding deregulation of Dicer and its influence on miRNA maturation is needed to predict the susceptibility of melanoma patients to miRNA-based therapy in the future.