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Acinetobacter baumannii is a major cause of bloodstream infections, yet its adaptation and survival mechanisms in human blood remain poorly understood. While previous studies focused on individual blood components, the impact of human whole blood on A. baumannii gene expression has not been explored. To address this, we used an ex vivo model where A. baumannii was grown in human whole blood from healthy volunteers (WBHV) and compared its gene expression to that in Luria-Bertani (LB) broth using RNA-seq. Our lab has previously employed a similar WBHV vs. LB comparison in Pseudomonas aeruginosa , validating this approach. Our results showed that ribosome biogenesis was the most upregulated pathway in WBHV, with 51 out of 55 ribosomal protein genes exhibiting increased expression. We then examined virulence related genes and found upregulation in iron and zinc acquisition systems ( acinetobactin, znuABC ) and biofilm/quorum sensing regulators, including the csu operon. Given these findings, we hypothesized that WBHV exposure enhances virulence. Using the Galleria mellonella infection model, we confirmed that A. baumannii caused higher larval mortality when grown in WBHV than when grown in LB. Upregulation of the csu operon, involved in pili assembly, led us to investigate twitching motility, where we observed a significant increase in WBHV. Additionally, since A. baumannii exhibits high drug resistance through the regulation of various outer membrane proteins (OMPs), we analyzed OMP expression in response to WBHV. SDS-PAGE and LC-MS/MS analysis identified three OMPs—Omp33–36, CarO, and OmpA—that were downregulated in WBHV. As these proteins mediate carbapenem uptake, we tested imipenem resistance using a minimum bactericidal concentration (MBC) assay and found that WBHV exposure increased A. baumannii ’s MBC to imipenem, suggesting reduced susceptibility. Our findings provide valuable insights into the adaptive mechanisms of A. baumannii in human whole blood, highlighting potential targets for combating its persistence and antibiotic resistance in bloodstream infections.

HIV-infection of microglia and macrophages (MMs) induces neuronal injury and chronic release of inflammatory stimuli through direct and indirect molecular pathways. A large percentage of people with HIV-associated neurologic and psychiatric co-morbidities have high levels of circulating inflammatory molecules. Microglia, given their susceptibility to HIV infection and long-lived nature, are reservoirs for persistent infection. MMs and neurons possess the molecular machinery to detect pathogen nucleic acids and proteins to activate innate immune signals. Full activation of inflammasome assembly and expression of IL-1β requires a priming event and a second signal. Many studies have demonstrated that HIV infection alone can activate inflammasome activity. Interestingly, secreted phosphoprotein-1 ( SPP1 /OPN) expression is highly upregulated in the CNS of people infected with HIV and neurologic dysfunction. Interestingly, all evidence thus far suggests a protective function of SPP1 signaling through mammalian target of rapamycin (mTORC1/2) pathway function to counter HIV-neuronal injury. Moreover, HIV-infected mice knocked down for SPP1 show by neuroimaging, increased neuroinflammation compared to controls. This suggests that SPP1 uses unique regulatory mechanisms to control the level of inflammatory signaling. In this mini review, we discuss the known and yet-to-be discovered biological links between SPP1 -mediated stimulation of mTOR and inflammasome activity. Additional new mechanistic insights from studies in relevant experimental models will provide a greater understanding of crosstalk between microglia and neurons in the regulation of CNS homeostasis.

Studies have suggested that alkalinized foods may reduce the effects of the acidogenic Western diet in promoting obesity, metabolic syndrome, type 2 diabetes, cancer, and coronary heart disease. Indeed, a recent study in mice fed a high-fat diet containing dietary beef supplemented with ammonium hydroxide showed improvement in a suite of metabolic outcomes. However, the effects of dietary protein ammonium supplementation on the microbiome remain unknown. In this study, the effects of ammonium supplementation on beef protein towards microbiome taxa and function in a high-fat diet were analyzed. Fecal microbiomes were characterized using a shotgun metagenomic approach for 16-month-old male and female mice after long-term diet treatments. The results for ammoniated diets showed that several bacteria known to be associated with health benefits increased significantly, including Romboutsia, Oscillospiraceae, and Lactococcus cremoris. The beneficial mucin-degrader Akkermansia was especially abundant, with a high prevalence (~86%) in females. Concurrently, the phyla Actinomycetota (Actinobacteria) and Bacteroidota (Bacteroidetes) were significantly reduced. While sex was a confounding factor affecting microbiome responses to ammonium supplementation in dietary protein, it is worth noting that several putatively beneficial microbiome functions increased with ammonium supplementation, such as glycine betaine transport, xenobiotic detoxification, enhanced defense, and others. Conversely, many disease-associated microbiome functions reduced. Importantly, modifying protein pH alone via ammonium supplementation induced beneficial microbiota changes. Taken together, these results suggest that ammonium-supplemented proteins may mediate some negative microbiome-associated effects of high-fat/Western diets.

The N50 statistic, a common statistical measure for average length of a set of sequences (see S1 Text for more detail) was 8,863 bp on average for the six PPN species analyzed. Since nematode genes average ~2-3 kb in length [1,11,12], the contigs resulting from our single-pass assembly are sufficiently long to be useful database resources for BLAST [14]. Genome skimming summary information and effector gene hits. http://dx.doi.org/10.1371/journal.ppat.1005713.t001 Characterizing Genomic Variation Early genome sequencing initiatives focused on model organisms such as C. elegans, in which sequenced DNA came from highly inbred lab populations. The median number of orthologs detected was 2 for all 3 Pratylenchus species.\\n The addition of a simple single BLAST step to our genome skimming strategy quickly revealed the presence of numerous putative effector genes in the PPN species, though follow-up experimentation and analysis remains necessary to evaluate whether or not bona fide effectors are encoded by the DNA sequences identified.

Purkinje cells receive synaptic input from several classes of interneurons. Here, we address the roles of inhibitory molecular layer interneurons in establishing Purkinje cell function in vivo . Using conditional genetics approaches in mice, we compare how the lack of stellate cell versus basket cell GABAergic neurotransmission sculpts the firing properties of Purkinje cells. We take advantage of an inducible Ascl1 CreER allele to spatially and temporally target the deletion of the vesicular GABA transporter, Vgat , in developing neurons. Selective depletion of basket cell GABAergic neurotransmission increases the frequency of Purkinje cell simple spike firing and decreases the frequency of complex spike firing in adult behaving mice. In contrast, lack of stellate cell communication increases the regularity of Purkinje cell simple spike firing while increasing the frequency of complex spike firing. Our data uncover complementary roles for molecular layer interneurons in shaping the rate and pattern of Purkinje cell activity in vivo .

The compartmentalization of the cerebellum into modules is often used to discuss its function. What, exactly, can be considered a module, how do they operate, can they be subdivided and do they act individually or in concert are only some of the key questions discussed in this consensus paper. Experts studying cerebellar compartmentalization give their insights on the structure and function of cerebellar modules, with the aim of providing an up-to-date review of the extensive literature on this subject. Starting with an historical perspective indicating that the basis of the modular organization is formed by matching olivocorticonuclear connectivity, this is followed by consideration of anatomical and chemical modular boundaries, revealing a relation between anatomical, chemical, and physiological borders. In addition, the question is asked what the smallest operational unit of the cerebellum might be. Furthermore, it has become clear that chemical diversity of Purkinje cells also results in diversity of information processing between cerebellar modules. An additional important consideration is the relation between modular compartmentalization and the organization of the mossy fiber system, resulting in the concept of modular plasticity. Finally, examination of cerebellar output patterns suggesting cooperation between modules and recent work on modular aspects of emotional behavior are discussed. Despite the general consensus that the cerebellum has a modular organization, many questions remain. The authors hope that this joint review will inspire future cerebellar research so that we are better able to understand how this brain structure makes its vital contribution to behavior in its most general form.

Tremor is currently ranked as the most common movement disorder. The brain regions and neural signals that initiate the debilitating shakiness of different body parts remain unclear. Here, we found that genetically silencing cerebellar Purkinje cell output blocked tremor in mice that were given the tremorgenic drug harmaline. We show in awake behaving mice that the onset of tremor is coincident with rhythmic Purkinje cell firing, which alters the activity of their target cerebellar nuclei cells. We mimic the tremorgenic action of the drug with optogenetics and present evidence that highly patterned Purkinje cell activity drives a powerful tremor in otherwise normal mice. Modulating the altered activity with deep brain stimulation directed to the Purkinje cell output in the cerebellar nuclei reduced tremor in freely moving mice. Together, the data implicate Purkinje cell connectivity as a neural substrate for tremor and a gateway for signals that mediate the disease.

Age-related neurodegenerative diseases involve reduced cell numbers and impaired behavioral capacity. Neurodegeneration and behavioral deficits also occur during aging, and notably in the absence of disease. The cerebellum, which modulates movement and cognition, is susceptible to cell loss in both aging and disease. Here, we demonstrate that cerebellar Purkinje cell loss in aged mice is not spatially random but rather occurs in a pattern of parasagittal stripes. We also find that aged mice exhibit impaired motor coordination and more severe tremor compared to younger mice. However, the relationship between patterned Purkinje cell loss and motor dysfunction is not straightforward. Examination of postmortem samples of human cerebella from neurologically typical individuals supports the presence of selective loss of Purkinje cells during aging. These data reveal a spatiotemporal cellular substrate for aging in the cerebellum that may inform how neuronal vulnerability leads to neurodegeneration and the ensuing deterioration of behavior. Aging involves the gradual loss of brain cells and a decline in physical and cognitive capabilities. One brain region affected by aging is the cerebellum, which is best known for its role in motor coordination. During healthy aging, the cerebellum is reduced in size, and elderly individuals often face difficulties with balance and motor skills. This shrinkage is partly caused by the loss of neurons, particularly Purkinje cells. A reduction in Purkinje cells and impaired motor function have also been seen in rodents during normal aging. Furthermore, in many rodent models of disease, not all Purkinje cells are equally likely to die. The surviving cells form specific patterns similar to those seen during cerebellar development. However, it has so far been unclear whether such regional differences in Purkinje cell loss also occur during healthy aging. Addressing this question would shed light on how aging influences cellular susceptibility and resilience in the cerebellum and how these cellular responses affect motor function and age-related cell death. To find out whether loss of Purkinje cells in aged mice occurs in a similar pattern observed during disease, Donofrio et al. used a combination of genetic, histological, and imaging techniques to visualize Purkinje cells in the cerebellum. The results revealed that the loss of Purkinje cells in healthy aged mice occurred in a pattern similar to that often observed in models of disease. However, the overall pattern in aged mice was distinct and occurred in a parasagittal, striped pattern – that is, long, narrow, and running front-to-back through the cerebellum. In addition, examining human cerebellum tissue samples collected from individuals without any reported neurological or neuropsychiatric problems confirmed a loss of Purkinje cells that increased with age. However, a specific pattern remains to be confirmed. Our study reveals a cerebellar framework of vulnerability and resistance to age-related cell death. These findings could enhance healthy brain aging by improving the precision of targeted therapeutics and opening avenues for preventative strategies to reduce or prevent cell loss. The essential step is to fully understand when and how cerebellar neurons degenerate across the human lifespan.

Background Microbiomes are critical to plants, promoting growth, elevating stress tolerance, and expanding the plant’s metabolic repertoire with novel defense pathways. However, generally microbiomes within plant tissues, which intimately interact with their hosts, remain poorly characterized. These endospheres have become a focus in banana ( Musa spp.)—an important plant for study of microbiome-based disease protection. Banana is important to global food security, while also being critically threatened by pandemic diseases. Domestication and clonal propagation are thought to have depleted protective microbiomes, whereas wild relatives may hold promise for new microbiome-based biological controls. The goal was to compare metapangenomes enriched from 7 Musa genotypes, including wild and cultivated varieties grown in sympatry, to assess the host associations with root and leaf endosphere functional profiles. Results Density gradients successfully generated culture-free microbial enrichment, dominated by bacteria, with all together 24,325 species or strains distinguished, and 1.7 million metagenomic scaffolds harboring 559,108 predicted gene clusters. About 20% of sequence reads did not match any taxon databases and ~ 62% of gene clusters could not be annotated to function. Most taxa and gene clusters were unshared between Musa genotypes. Root and corm tissues had significantly richer endosphere communities that were significantly different from leaf communities. Agrobacterium and Rhizobium were the most abundant in all samples while Chitinophagia and Actinomycetia were more abundant in roots and Flavobacteria in leaves. At the bacterial strain level, there were > 2000 taxa unique to each of M. acuminata (AAA genotype) and M. balbisiana (B-genotype), with the latter ‘wild’ relatives having richer taxa and functions. Gene ontology functional enrichment showed core beneficial functions aligned with those of other plants but also many specialized prospective beneficial functions not reported previously. Some gene clusters with plant-protective functions showed signatures of phylosymbiosis, suggesting long-standing associations or heritable microbiomes in Musa . Conclusions Metapangenomics revealed key taxa and protective functions that appeared to be driven by genotype, perhaps contributing to host resistance differences. The recovery of rich novel taxa and gene clusters provides a baseline dataset for future experiments in planta or in vivo bacterization or engineering of wild host endophytes.

The cerebellum contributes to a diverse array of motor conditions, including ataxia, dystonia, and tremor. The neural substrates that encode this diversity are unclear. Here, we tested whether the neural spike activity of cerebellar output neurons is distinct between movement disorders with different impairments, generalizable across movement disorders with similar impairments, and capable of causing distinct movement impairments. Using in vivo awake recordings as input data, we trained a supervised classifier model to differentiate the spike parameters between mouse models for ataxia, dystonia, and tremor. The classifier model correctly assigned mouse phenotypes based on single-neuron signatures. Spike signatures were shared across etiologically distinct but phenotypically similar disease models. Mimicking these pathophysiological spike signatures with optogenetics induced the predicted motor impairments in otherwise healthy mice. These data show that distinct spike signatures promote the behavioral presentation of cerebellar diseases. Intentional movement is fundamental to achieving many goals, whether they are as complicated as driving a car or as routine as feeding ourselves with a spoon. The cerebellum is a key brain area for coordinating such movement. Damage to this region can cause various movement disorders: ataxia (uncoordinated movement); dystonia (uncontrolled muscle contractions); and tremor (involuntary and rhythmic shaking). While abnormal electrical activity in the brain associated with movement disorders has been recorded for decades, previous studies often explored one movement disorder at a time. Therefore, it remained unclear whether the underlying brain activity is similar across movement disorders. Van der Heijden and Brown et al. analyzed recordings of neuron activity in the cerebellum of mice with movement disorders to create an activity profile for each disorder. The researchers then used machine learning to generate a classifier that could separate profiles associated with manifestations of ataxia, dystonia, and tremor based on unique features of their neural activity. The ability of the model to separate the three types of movement disorders indicates that abnormal movements can be distinguished based on neural activity patterns. When additional manifestations of these abnormal movements were considered, multiple mouse models of dystonia and tremor tended to show similar profiles. Ataxia models had several different types of neural activity that were all distinct from the dystonia and tremor profiles. After identifying the activity associated with each movement disorder, Van der Heijden and Brown et al. induced the same activity in the cerebella of healthy mice, which then caused the corresponding abnormal movements. These findings lay an important groundwork for the development of treatments for neurological disorders involving ataxia, dystonia, and tremor. They identify the cerebellum, and specific patterns of activity within it, as potential therapeutic targets. While the different activity profiles of ataxia may require more consideration, the neural activity associated with dystonia and tremor appears to be generalizable across multiple manifestations, suggesting potential treatments could be broadly applicable for these disorders.