A Mathematical Model of Chlamydial Infection Incorporating Movement of Chlamydial Particles

We present a spatiotemporal mathematical model of chlamydial infection, host immune response, and movement of infectious particles. The resulting partial differential equations model both the dynamics of the infection and changes in infection profile observed spatially along the length of the host genital tract. This model advances previous Chlamydia modelling by incorporating spatial change. Numerical solutions and model analysis are carried out, and we present a hypothesis regarding the potential for treatment and prevention of infection by increasing chlamydial particle motility.     

Characterization of Ichthyocidal Activity of Pfiesteria piscicida: Dependence on the Dinospore Cell Density

The ichthyocidal activity of Pfiesteria piscicida dinospores was examined in an aquarium bioassay format by exposing fish to either Pfiesteria-containing environmental sediments or clonal P. piscicida. The presence of Pfiesteria spp. and the complexity of the microbial assemblage in the bioassay were assessed by molecular approaches. Cell-free water from bioassays that yielded significant fish mortality failed to show ichthyocidal activity. Histopathological examination of moribund and dead fish failed to reveal the skin lesions reported elsewhere. Fish larvae within “cages” of variable mesh sizes were killed in those where the pore size exceeded that of Pfiesteria dinospores. In vitro exposure of fish larvae to clonal P. piscicida indicated that fish mortality was directly proportional to the dinospore cell density. Dinospores clustered around the mouth, eyes, and operculi, suggesting that fish health may be affected by their direct interaction with skin, gill epithelia, or mucous surfaces. Molecular fingerprinting revealed the presence of a very diverse microbial community of bacteria, protists, and fungi within bioassay aquaria containing environmental sediments. Some components of the microbial community were identified as potential fish pathogens, preventing the rigorous identification of Pfiesteria spp. as the only cause of fish death. In summary, our results strongly suggest (i) that this aquarium bioassay format, which has been extensively reported in the literature, is unsuitable to accurately assess the ichthyocidal activity of Pfiesteria spp. and (ii) that the ichthyocidal activity of Pfiesteria spp. is mostly due to direct interactions of the zoospores with fish skin and gill epithelia rather than to soluble factors.     

Alginate/chitosan hydrogel containing olfactory ectomesenchymal stem cells for sciatic nerve tissue engineering

Regeneration and functional recovery after peripheral nerve damage still remain a significant clinical problem. In this study, alginate/chitosan (alg/chit) hydrogel was used for the transplantation of olfactory ectomesenchymal stem cells (OE-MSCs) to promote peripheral nerve regeneration. The OE-MSCs were isolated from olfactory mucosa biopsies and evaluated by different cell surface markers and differentiation capacity. After creating sciatic nerve injury in a rat model, OE-MSCs were transplanted to the injured area with alg/chit hydrogel which was prepared and well-characterized. The prepared hydrogel had the porosity of 91.3 ± 1.27%, the swelling ratio of 379% after 240 min, weight loss percentages of 80 ± 5.56% after 14 days, and good blood compatibility. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, 4′,6-diamidino-2-phenylindole, and LIVE/DEAD staining were done to assay the behavior of OE-MSCs on alg/chit hydrogel and the results confirmed that the hydrogel can provide a suitable substrate for cell survival. For functional analysis, alg/chit hydrogel with and without OE- MSCs was injected into a 3-mm sciatic nerve defect of Wistar rats. The results of the sciatic functional index, hot plate latency, electrophysiological assessment, weight-loss percentage of wet gastrocnemius muscle, and histopathological examination using hematoxylin–eosin and Luxol fast blue staining showed that utilizing alg/chit hydrogel with OE-MSCs to the sciatic nerve defect enhance regeneration compared to the control group and hydrogel without cells.     

Real-time polymerase chain reaction assays for rapid detection and virulence evaluation of the environmental Pseudomonas aeruginosa isolates

Molecular Biology Reports - Rapid and species-specific detection, and virulence evaluation of opportunistic pathogens such as Pseudomonas aeruginosa, are issues that increasingly has attracted the...     

Priming with oxytocin and relaxin improves cardiac differentiation of adipose tissue–derived stem cells

Previous studies have identified the heart as a source and a target tissue for oxytocin and relaxin hormones. These hormones play important roles in the regulation of cardiovascular function and repair of ischemic heart injury. In the current study, we examined the impact of oxytocin and relaxin on the development of cardiomyocytes from mesenchymal stem cells. For this purpose, mouse adipose tissue–derived stem cells (ADSCs) were treated with different concentrations of oxytocin or relaxin for 4 days. Three weeks after initiation of cardiac induction, differentiated ADSCs expressed cardiac-specific genes, Gata4, Mef2c, Nkx2.5, Tbx5, α- and β-Mhc, Mlc2v, Mlc2a and Anp, and cardiac proteins including connexin 43, desmin and α-actinin. 10 ⁻⁷ M oxytocin and 50 ng/mL relaxin induced the maximum upregulation in the expression of cardiac markers. A combination of oxytocin and relaxin induced cardiomyocyte differentiation more potently than the individual factors. In our experiment, oxytocin-relaxin combination increased the population of cardiac troponin I-expressing cells to 6.84% as compared with 2.36% for the untreated ADSCs, 3.7% for oxytocin treatment and 3.41% for relaxin treatment groups. In summary, the results of this study indicated that oxytocin and relaxin hormones individually and in combination can improve cardiac differentiation of ADSCs, and treatment of the ADSCs and possibly other mesenchymal stem cells with these hormones may enhance their cardiogenic differentiation and survival after transplantation into the ischemic heart tissue.     

Astaxanthin Modulates Autophagy,Apoptosis, and Neuronal Oxidative Stress in a Rat Model of Compression Spinal Cord Injury

The effects of astaxanthin (AST) were evaluated on oxidative mediators, neuronal apoptosis, and autophagy in functional motor recovery after spinal cord injury (SCI). Rats were divided into three groups of sham, SCI?+?DMSO (dimethyl sulfoxide), and SCI?+?AST. Rats in the sham group only underwent a laminectomy at thoracic 8–9. While, the SCI?+?DMSO and SCI?+?AST groups had a compression SCI with an aneurysm clip. Then, this groups received an intrathecal (i.t.) injection of 5% DMSO and AST (10 μl of 0.005 mg/kg), respectively. The rat motor functions were assessed weekly until the 28th day using a combined behavioral score (CBS). Total antioxidant capacity (TAC), malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GPx) were measured in spinal tissue to evaluate oxidative stress-related parameters. Besides, autophagy-related proteins (P62, LC3B, and Beclin1) and apoptosis-associated proteins (Bax and Bcl2) were determined using western blotting on the 1st and 7th days after surgery. Hematoxylin–eosin and Fluoro-Jade B staining were performed to detect the histological alterations and neuronal degeneration. As the result, treatment with AST potentially attenuated rat CBS scores (p?<?0.001) towards a better motor performance. AST significantly reduced the spinal level of oxidative stress by increasing TAC, SOD, and GPx, while decreasing MDA (p?<?0.001). Furthermore, AST treatment remarkably upregulated expression of LC3B (p?<?0.001), and Beclin1 (p?<?0.05) in the spinal cord, but downregulated P62 (p?<?0.05) and the Bax/Bcl2 ratio (p?<?0.001). Consequently, AST reduced SCI-induced histological alterations and neuronal degeneration (p?<?0.001). In conclusion, AST can improve motor function after SCI by reducing oxidative stress/apoptosis and increasing neuronal autophagy.

     

Boosting riboswitch efficiency by RNA amplification

Riboswitches are RNA sensors that regulate gene expression in response to binding of small molecules. Although they conceptually represent simple on/off switches and, therefore, hold great promise for biotechnology and future synthetic biology applications, the induction of gene expression by natural riboswitches after ligand addition or removal is often only moderate and, consequently, the achievable expression levels are not very high. Here, we have designed an RNA amplification-based system that strongly improves the efficiency of riboswitches. We have successfully implemented the method in a biological system for which currently no efficient endogenous tools for inducible (trans)gene expression are available: the chloroplasts of higher plants. We further show that an HIV antigen whose constitutive expression from the chloroplast genome is deleterious to the plant can be inducibly expressed under the control of the RNA amplification-enhanced riboswitch (RAmpER) without causing a mutant phenotype, demonstrating the potential of the method for the production of proteins and metabolites that are toxic to the host cell.     

De novo complex chromosomal rearrangement of 46, XY,t (3; 16; 8) (p26; q13; q21.2) in a non-obstructive azoospermic male

Complex Chromosomal Rearrangements (CCRs) are rare structural abnormalities that are usually associated with infertility or subfertility in male carriers. We described clinical and chromosomal features of a non-obstructive azoospermic male that has been referred for infertility. Cytogenetic analysis showed three chromosomes, i.e. 3, 8 and 16, which have been involved and caused spermatogenesis failure.     

Comparative Evaluation of Three Supplements for Helicobacter pylori Growth in Liquid Culture

Helicobacter pylori, a microaerophilic fastidious bacterium, has been cultured on various plating and broth media since its discovery. Although the agar media can be sufficient for the identification, typing, and antibiotic resistance studies, no secretory antigen of H. pylori can be evaluated in such media. Thus, satisfactory growth of H. pylori in liquid culture which is needed for analysis of secretory proteins without the presence of interfering agents is in demand. We assessed the impact of β-cyclodextrin, Fetal Bovine Serum (FBS), and charcoal as supplements for H. pylori growth. Furthermore, we aimed to identify the most favorable supplement that supports the secretion of the dominant secretory protein, vacuolating cytotoxin (VacA). Five clinical strains were cultured on broth media and the growth, viability, morphology, and protein content of each strain were determined. Our results revealed that β-cyclodextrin supports the growth rate, viability, and cell lysate protein content to the extent similar to FBS. Application of β-cyclodextrin is found to postpone spiral to coccoid conversion up to 72 h of incubation. Although FBS supports a higher VacA protein content, presence of interfering macromolecules in FBS questions its utility particularly for purposes of studying extra cellular proteins such as VacA. This study recommends further application of β-cyclodextrin as a culture supplement with the potential capacity in neutralizing toxic compounds and flourishing the secretion of H. pylori proteins without addition of interfering proteins.