Additional fertilizer and nematicide combinations on upland cotton to manage Rotylenchulus reniformis and Meloidogyne incognita in Alabama.

Plant parasitic nematodes are major pests on upland cotton worldwide and in the United States. The reniform nematode, Rotylenchulus reniformis and the southern root-knot nematode Meloidogyne incognita are some of the most damaging nematodes on cotton in the United States. Current management strategies focus on reducing nematode populations with nematicides. The objective of this research was to integrate additional fertilizer and nematicide combinations into current practices to establish economical nematode management strategies while promoting cotton yield and profit. Microplot and field trials were run to evaluate fertilizer and nematicide combinations applied at the pinhead square (PHS) and first bloom (FB) plant growth stages to reduce nematode population density and promote plant growth and yield. Cost efficiency was evaluated based on profit from lint yields and chemical input costs. Data combined from 2019 and 2020 suggested a nematicide seed treatment (ST) ST + (NH4)2SO4 + Vydate® C-LV + Max-In® Sulfur was the most effective in increasing seed cotton yields in the R. reniformis microplot trials. In R. reniformis field trials, a nematicide ST + (NH4)2SO4 + Vydate® C-LV at PHS supported the largest lint yield and profit per hectare at $1176. In M. incognita field trials, a nematicide ST + 28-0-0-5 + Vydate® C-LV + Max-In® Sulfur at PHS and FB supported the largest lint yields and profit per hectare at $784. These results suggest that combinations utilizing fertilizers and nematicides applied together across the season in addition to current fertility management show potential to promote yield and profit in R. reniformis and M. incognita infested cotton fields.

High-content analysis and Kinetic Image Cytometry identify toxicity and epigenetic effects of HIV antiretrovirals on human iPSC-neurons and primary neural precursor cells.

INTRODUCTION: Despite viral suppression due to combination antiretroviral therapy (cART), HIV-associated neurocognitive disorders (HAND) continue to affect half of people with HIV, suggesting that certain antiretrovirals (ARVs) may contribute to HAND. METHODS: We examined the effects of nucleoside/nucleotide reverse transcriptase inhibitors tenofovir disoproxil fumarate (TDF) and emtricitabine (FTC) and the integrase inhibitors dolutegravir (DTG) and elvitegravir (EVG) on viability, structure, and function of glutamatergic neurons (a subtype of CNS neuron involved in cognition) derived from human induced pluripotent stem cells (hiPSC-neurons), and primary human neural precursor cells (hNPCs), which are responsible for neurogenesis. RESULTS: Using automated digital microscopy and image analysis (high content analysis, HCA), we found that DTG, EVG, and TDF decreased hiPSC-neuron viability, neurites, and synapses after 7 days of treatment. Analysis of hiPSC-neuron calcium activity using Kinetic Image Cytometry (KIC) demonstrated that DTG and EVG also decreased the frequency and magnitude of intracellular calcium transients. Longer ARV exposures and simultaneous exposure to multiple ARVs increased the magnitude of these neurotoxic effects. Using the Microscopic Imaging of Epigenetic Landscapes (MIEL) assay, we found that TDF decreased hNPC viability and changed the distribution of histone modifications that regulate chromatin packing, suggesting that TDF may reduce neuroprogenitor pools important for CNS development and maintenance of cognition in adults. CONCLUSION: This study establishes human preclinical assays that can screen potential ARVs for CNS toxicity to develop safer cART regimens and HAND therapeutics.

Mutant huntingtin impairs PNKP and ATXN3, disrupting DNA repair and transcription.

How huntingtin (HTT) triggers neurotoxicity in Huntington's disease (HD) remains unclear. We report that HTT forms a transcription-coupled DNA repair (TCR) complex with RNA polymerase II subunit A (POLR2A), ataxin-3, the DNA repair enzyme polynucleotide-kinase-3'-phosphatase (PNKP), and cyclic AMP-response element-binding (CREB) protein (CBP). This complex senses and facilitates DNA damage repair during transcriptional elongation, but its functional integrity is impaired by mutant HTT. Abrogated PNKP activity results in persistent DNA break accumulation, preferentially in actively transcribed genes, and aberrant activation of DNA damage-response ataxia telangiectasia-mutated (ATM) signaling in HD transgenic mouse and cell models. A concomitant decrease in Ataxin-3 activity facilitates CBP ubiquitination and degradation, adversely impacting transcription and DNA repair. Increasing PNKP activity in mutant cells improves genome integrity and cell survival. These findings suggest a potential molecular mechanism of how mutant HTT activates DNA damage-response pro-degenerative pathways and impairs transcription, triggering neurotoxicity and functional decline in HD.

MAP4K3 mediates amino acid-dependent regulation of autophagy via phosphorylation of TFEB.

Autophagy is the major cellular pathway by which macromolecules are degraded, and amino acid depletion powerfully activates autophagy. MAP4K3, or germinal-center kinase-like kinase, is required for robust cell growth in response to amino acids, but the basis for MAP4K3 regulation of cellular metabolic disposition remains unknown. Here we identify MAP4K3 as an amino acid-dependent regulator of autophagy through its phosphorylation of transcription factor EB (TFEB), a transcriptional activator of autophagy, and through amino acid starvation-dependent lysosomal localization of MAP4K3. We document that MAP4K3 physically interacts with TFEB and MAP4K3 inhibition is sufficient for TFEB nuclear localization, target gene transactivation, and autophagy, even when mTORC1 is activated. Moreover, MAP4K3 serine 3 phosphorylation of TFEB is required for TFEB interaction with mTORC1-Rag GTPase-Ragulator complex and TFEB cytosolic sequestration. Our results uncover a role for MAP4K3 in the control of autophagy and reveal MAP4K3 as a central node in nutrient-sensing regulation.

Exploring the influence of torsinA expression on protein quality control.

DYT1 dystonia is caused by a glutamic acid deletion (ΔE) in the endoplasmic reticulum (ER) protein torsinA. Previous studies suggest that torsinA modulates the aggregation of cytosolic misfolded proteins and ER stress responses, although the mechanisms underlying those effects remain unclear. In order to investigate the bases of these observations, we analyzed the interaction between torsinA expression, protein aggregation and ER stress in PC6.3 cells. Unexpectedly, we found that expression of torsinA(wt) or (ΔE) does not influence the inclusion formation by an expanded polyglutamine reporter protein in this cellular model. Furthermore, torsinA does not prevent the activation of ER stress induced by thapsigargin or the reducing agent DTT. Interestingly, DTT induces post-translational changes in torsinA, more prominently for torsinA(wt) than (ΔE). This work highlights the importance of model system selection for the study of torsinA function. Furthermore, it provides additional evidence suggesting that torsinA is sensitive to changes in the cellular redox potential.