Iron necessity for chlamydospore germination in Fusarium oxysporum f. sp. cubense TR4

Fusarium wilt disease of banana, caused by the notorious soil-borne pathogen Fusarium oxysporum f. sp. cubense Tropical Race 4 (Foc TR4), is extremely difficult to manage. Manipulation of soil pH or application of synthetic iron chelators can suppress the disease through iron starvation, which inhibits the germination of pathogen propagules called chlamydospores. However, the effect of iron starvation on chlamydospore germination is largely unknown. In this study, scanning electron microscopy was used to assemble the developmental sequence of chlamydospore germination and to assess the effect of iron starvation and pH in vitro. Germination occurs in three distinct phenotypic transitions (swelling, polarized growth, outgrowth). Outgrowth, characterized by formation of a single protrusion (germ tube), occurred at 2 to 3 h, and a maximum value of 69.3% to 76.7% outgrowth was observed at 8 to 10 h after germination induction. Germination exhibited plasticity with pH as over 60% of the chlamydospores formed a germ tube between pH 3 and pH 11. Iron-starved chlamydospores exhibited polarized-growth arrest, characterized by the inability to form a germ tube. Gene expression analysis of rnr1 and rnr2, which encode the iron-dependent enzyme ribonucleotide reductase, showed that rnr2 was upregulated (p < 0.0001) in iron-starved chlamydospores compared to the control. Collectively, these findings suggest that iron and extracellular pH are crucial for chlamydospore germination in Foc TR4. Moreover, inhibition of germination by iron starvation may be linked to a different mechanism, rather than repression of the function of ribonucleotide reductase, the enzyme that controls growth by regulation of DNA synthesis.

Effects of exercise mode and intensity on patient-reported outcomes in cancer survivors: a four-arm intervention trial

PURPOSE

The aim of this study was to compare the effects of different exercise modes (aerobic, resistance) and intensity prescriptions (standard, polarized, undulating) on patient-reported outcomes (PROs) in cancer survivors.

METHODS

107 breast or prostate cancer survivors (52% females, age 58 ± 10 years, 6-52 weeks after primary therapy) performed one out of four training programs, two sessions/week, over 12 weeks: work rate-matched vigorous intensity aerobic training (AT_Standard, n = 28) and polarized intensity aerobic training (AT_Polarized, n = 26) as well as volume-matched moderate intensity resistance training (RT_Standard, n = 26) and daily undulating intensity resistance training (RT_Undulating, n = 27). Health-related quality of life (HRQoL, EORTC-QLQ-C30) and cancer-related fatigue (CRF, MFI-20) were assessed at baseline, at the end of intervention and after a 12-week follow-up without further prescribed exercise.

RESULTS

Over the intervention period, HRQoL-function-scales of the EORTC-QLQ-C30 improved over time (p = .007), but no group*time interaction was observed (p = .185). Similarly, CRF values of the MFI-20 improved over time (p = .006), but no group*time interaction was observed (p = .663). When including the follow-up period and pooling the AT and the RT groups, HRQoL-function-scales developed differently between groups (p = .022) with further improvements in RT and a decline in AT. For CRF no significant interaction was found, but univariate analyses showed a non-significant trend of more sustainable effects in RT.

CONCLUSIONS

AT and RT with different work rate-/volume-matched intensity prescriptions elicits positive effects on HRQoL and CRF, without one regimen being significantly superior to another over the intervention period. However, RT might result in more sustainable effects compared to AT over a follow-up period without any further exercise prescription.

CLINICAL TRIAL REGISTRATION

The study was registered at clinicaltrials.gov (NCT02883699).

Performance enhancement of an FSO link using polarized quasi-diffuse transmitter

Free space optics (FSO) system has received much interest in recent years as a technology that exhibits cost-effective, better security, license-free, and comprehensive capacity access techniques for transmission of Giga data rate. However, despite all the many advantages demonstrated by its signal, alignment distortion from building sway, atmospheric disturbances from aerosol, scattering, turbulence, and scintillation have shackled the development of the high-speed FSO link and made it less attractive. These atmospheric disturbances have led to the cultivation of spatial diversity techniques for its performance improvement. This work proposes applying a polarized quasi-diffused system with a power divider/holographic beam splitter as a spatial diversity scheme instead of using multiple transmitters. The idea of both analytical and simulation design is considered. The proposed model with power divider/holographic beam splitter has shown a very high maximum quality factor, improved received power, better bit error rate (BER), and eye height depicting the link visibility as compared to the conventional point to point single input single output (SISO) 1TX/RX FSO system for the same transmitted power and link range. The results and data were collected through the help of optisystem software. The obtained results show better performance of an FSO link by using a single transmitter with multi-beam spots from a power divider/hologram instead of using multiple transmitters as a spatial diversity scheme.

The role of HIF-1α in BCG-stimulated macrophages polarization and their tumoricidal effects in vitro

BCG is widely used for cancer treatment, where macrophages play an important role. However, the mechanism of BCG affecting macrophages remains poorly understood. In this study, we used BCG to stimulate myeloid-derived macrophages lacking HIF-1α, the levels of TNF-α, IL-1β, CD86 of macrophages and their effects on the growth of tumor cells MCA207 and B16-F10 were detected. We found that the absence of HIF-1α prevents BCG-stimulated macrophages from polarizing towards the M (BCG) and attenuating its killing effect on tumor cells. In addition, we demonstrated that the tumors of mice lacking HIF-1α in macrophages were significantly increased by the experiment of mice transplantation. Our study provides relevant evidence for exploring the mechanism of the BCG vaccine in the prevention and treatment of related diseases.

Destination and consequences of Panx1 and mutant expression in polarized MDCK cells

The channel-forming membrane glycoprotein pannexin 1 (Panx1) is best characterized as an ATP release channel. To investigate the trafficking and sorting of Panx1, we used polarized MDCK cells and non-polarized BICR-M1R_k cells to track the fate of GFP-tagged Panx1. In non-polarized cells, Panx1 was found throughout the plasma membrane, including the lamellipodia of the tumor cells and the cell surface-targeting domain was mapped to residues 307-379. Panx1 was preferentially enriched at the apical membrane domain of polarized MDCK cells grown as monolayer sheets or as spheroids. Residual Panx1 localized within basolateral membranes of polarized MDCK cells was independent of a putative dileucine sorting motif LL365/6 found within the C-terminal of Panx1. Unexpectedly, stable expression of a Panx1 mutant, where a putative tyrosine-based basolateral sorting motif (YxxØ) was mutated (Y308F), or a truncated Δ379 Panx1 mutant, caused MDCK cells to lose cell-cell contacts and their ability to polarize as they underwent a switch to a more fibroblast-like phenotype. We conclude that Panx1 is preferentially delivered to the apical domain of polarized epithelial cells, and Panx1 mutants drive phenotypic changes to MDCK cells preventing their polarization.

Isolation of Retinal Exosome Biomarkers from Blood by Targeted Immunocapture

The retinal pigmented epithelium (RPE) forms the outer blood-retinal barrier, provides nutrients, recycles visual pigment, and removes spent discs from the photoreceptors, among many other functions. Because of these critical roles in visual homeostasis, the RPE is a principal location of disease-associated changes in age-related macular degeneration (AMD), emphasizing its importance for study in both visual health and disease. Unfortunately, there are no early indicators of AMD or disease progression, a void that could be filled by the development of early AMD biomarkers. Exosomes are lipid bilayer membrane vesicles of nanoscale sizes that are released in a controlled fashion by cells and carry out a number of extra- and intercellular activities. In the RPE they are released from both the apical and basal sides, and each source has a unique signature/content. Exosomes released from the basolateral side of RPE cells enter the systemic circulation via the choroid and thus represent a potential source of retinal disease biomarkers in blood. Here we discuss the potential of targeted immunocapture of eye-derived exosomes and other small extracellular vesicles from blood for eye disease biomarker discovery.

Isolation and Culture of Juvenile Pig Thyroid Follicular Epithelia

Epithelial tissues are defined by their polarity and their ability to transport directionally. Thyroid is a tissue comprising functional epithelial units organized as enclosed follicles, with their luminal spaces defined by thyrocyte apices. Thus, the native arrangement of thyroid epithelia limits accessibility to the follicular space, presenting a challenge in studying transepithelial movements. This limitation can be overcome by studying thyrocytes grown as two-dimensional cultures. Herein we present methods for isolation of thyroid follicles from juvenile pigs and preparation of high-resistance, polarized cultures.

Polarized Exosome Release from the Retinal Pigmented Epithelium

The retinal pigmented epithelium (RPE) forms the outer blood-retinal barrier and provides nutrients and recycling of visual pigment to the photoreceptors, among many other functions. The RPE is also a key site of pathophysiological changes in age-related macular degeneration, making it an important focus of study in both visual health and disease. Exosomes are nanometer-sized vesicles that are released by cells in a controlled fashion and mediate a range of extra- and intercellular activities. Some key exosome actions include cell-cell communication, immune modulation, extracellular matrix turnover, stem cell division/differentiation, neovascularization, and cellular waste removal. While much is known about their role in cancer and cardiovascular disease, exosome function in the many specialized tissues of the eye is just beginning to undergo rigorous study. Here we review current knowledge of the functions and roles of exosomes and other small extracellular vesicles released from the RPE. In particular, we discuss the potential role and importance of polarized exosome release from the RPE.

Adenovirus transduction: More complicated than receptor expression

The abundance and accessibility of a primary virus receptor are critical factors that impact the susceptibility of a host cell to virus infection. The Coxsackievirus and adenovirus receptor (CAR) has two transmembrane isoforms that occur due to alternative splicing and differ in localization and function in polarized epithelia. To determine the relevance of isoform-specific expression across cell types, the abundance and localization of both isoforms were determined in ten common cell lines, and correlated with susceptibility to adenovirus transduction relative to polarized primary human airway epithelia. Data show that the gene and protein expression for each isoform of CAR varies significantly between cell lines and polarization, as indicated by high transepithelial resistance, is inversely related to adenovirus transduction. In summary, the variability of polarity and isoform-specific expression among model cells are critical parameters that must be considered when evaluating the clinical relevance of potential adenovirus-mediated gene therapy and anti-adenovirus strategies.