Dopamine-mediated interactions between short- and long-term memory dynamics.

In dynamic environments, animals make behavioral decisions based on the innate valences of sensory cues and information learnt about these cues across multiple timescales1-3. However, it remains unclear how the innate valence of a sensory stimulus affects acquisition of learnt valence information and subsequent memory dynamics. Here we show that in the Drosophila brain, interconnected short- and long-term memory units of the mushroom body jointly regulate memory via dopamine signals that encode innate and learnt sensory valences. Through time-lapse, in vivo voltage-imaging studies of neural spiking in >500 flies undergoing olfactory associative conditioning, we found that protocerebral posterior lateral 1 dopamine neurons (PPL1-DANs)4 heterogeneously and bi-directionally encode innate and learnt valences of punishment, reward, and odor cues. During learning, these valence signals regulate memory storage and extinction in mushroom body output neurons (MBONs)5. In initial conditioning bouts, PPL1-γ1pedc and PPL1-γ2α'1 neurons control short-term memory formation, which weakens inhibitory feedback from MBON-γ1pedc>α/ß to PPL1-α'2α2 and PPL1-α3. During further conditioning, this diminished feedback allows these two PPL1-DANs to encode the net innate plus learnt valence of the conditioned odor cue, which gates long-term memory formation. A computational model constrained by the fly connectome6,7 and our spiking data explains how dopamine signals mediate the circuit interactions between short- and long-term memory traces, yielding predictions that our experiments confirm. Overall, the mushroom body achieves flexible learning via the integration of innate and learnt valences within parallel learning units sharing feedback interconnections. This hybrid physiologic-anatomic mechanism may be a general means by which dopamine regulates memory dynamics in other species and brain structures, including the vertebrate basal ganglia.

Mitochondrial complex I activity in microglia sustains neuroinflammation.

Sustained smouldering, or low-grade activation, of myeloid cells is a common hallmark of several chronic neurological diseases, including multiple sclerosis1. Distinct metabolic and mitochondrial features guide the activation and the diverse functional states of myeloid cells2. However, how these metabolic features act to perpetuate inflammation of the central nervous system is unclear. Here, using a multiomics approach, we identify a molecular signature that sustains the activation of microglia through mitochondrial complex I activity driving reverse electron transport and the production of reactive oxygen species. Mechanistically, blocking complex I in pro-inflammatory microglia protects the central nervous system against neurotoxic damage and improves functional outcomes in an animal disease model in vivo. Complex I activity in microglia is a potential therapeutic target to foster neuroprotection in chronic inflammatory disorders of the central nervous system3.

Mutant Huntingtin Drives Development of an Advantageous Brain Early in Life: Evidence in Support of Antagonistic Pleiotropy.

OBJECTIVE: Huntington's disease (HD) is a neurodegenerative disease caused by a triplet repeat expansion within the gene huntingtin (HTT). Antagonistic pleiotropy is a theory of aging that posits that some genes, facilitating individual fitness early in life through adaptive evolutionary changes, also augment detrimental aging-related processes. Antagonistic pleiotropy theory may explain a positive evolutionary pressure toward functionally advantageous brain development that is vulnerable to rapid degeneration. The current study investigated antagonistic pleiotropy in HD using a years-to-onset paradigm in a unique sample of children and young adults at risk for HD. METHODS: Cognitive, behavioral, motor, and brain structural measures from premanifest gene-expanded (n = 79) and gene nonexpanded (n = 112) participants (6-21 years) in the Kids-HD study were examined. All measures in the gene-expanded group were modeled using a mixed-effects regression approach to assess years-to-onset-based changes while controlling for normal growth. Simultaneously, structure-function associations were also examined. RESULTS: Decades from motor onset, gene-expanded participants showed significantly better cognitive, behavioral, and motor scores versus gene nonexpanded controls, along with larger cerebral volumes and cortical features. After this initial peak, a prolonged deterioration was observed in both functional and structural measures. Far from onset, brain measures were positively correlated with functional measures, supporting the view that functional advantages were mediated by structural differences. INTERPRETATION: Mutant HTT may drive the development of a larger than normal brain that subserves superior early-life function. These findings support the antagonistic pleiotropy theory of HTT in HD, where this gene drives early advantage followed by accelerated aging processes. ANN NEUROL 2024.

TH2 cell compensatory effect following benralizumab treatment for eosinophilic gastritis.

BACKGROUND: Eosinophil accumulation is a main feature of eosinophilic gastritis (EoG) and is associated with its histologic diagnosis and pathology. However, a recent clinical trial has demonstrated that EoG endoscopic, noneosinophil histologic, and clinical features remain persistent despite complete eosinophil depletion. OBJECTIVE: Our aim was to examine gastric T-cell composition and associated cytokine levels of patients with EoG following benralizumab-induced eosinophil depletion versus following administration of placebo. METHODS: A cohort of subjects with EoG from a subset of subjects who participated in a recent phase 2 benralizumab trial was treated for 12 weeks with administration of 3 doses of benralizumab (anti-IL-5 receptor α antibody [n = 5]) or placebo (n = 4). Single-cell suspensions obtained by gastric biopsy were stimulated with phorbol 12,13-dibutyrate and ionomycin in the presence of brefeldin A and monensin. Harvested cells were fixed, stained, and analyzed by flow cytometry to examine T-cell populations and associated cytokines. RESULTS: Following benralizumab treatment but not placebo, blood and gastric eosinophil levels decreased 16-fold and 10-fold, respectively. Whereas histologic score and features were significantly decreased, no change was observed in endoscopic score and features. Following complete eosinophil depletion with benralizumab, gastric TH2 cell levels were 3-fold higher than the levels in the patients with EoG who were given placebo; and the levels of associated type 2 cytokine production of IL-4, IL-5, and IL-13 in the benralizumab-treated patients were, respectively, 4-, 5.5-, and 2.5-fold, higher than those in the placebo-treated patients. CONCLUSION: We have identified a putative positive feedback loop whereby eosinophil depletion results in a paradoxic increase in levels of TH2 cells and derived cytokines; this finding suggests an explanation for the limited success of eosinophil depletion as monotherapy in eosinophil-associated gastrointestinal disorders.

Alkene Hydrobenzylation by a Single Catalyst That Mediates Iterative Outer-Sphere Steps.

Cross-coupling catalysts typically react and unite functionally distinct partners via sequential inner-sphere elementary steps: coordination, migratory insertion, reductive elimination, etc. Here, we report a single catalyst that cross-couples styrenes and benzyl bromides via iterative outer-sphere steps: metal-ligand-carbon interactions. Each partner forms a stabilized radical intermediate, yet heterocoupled products predominate. The system is redox-neutral and, thus, avoids exogenous oxidants, resulting in simple and scalable conditions. Numerous variations of alkene hydrobenzylation are made possible, including access to the privileged heterodibenzyl (1,2-diarylethane) motif and challenging quaternary carbon variants.

Expanding the landscape of oncogenic drivers and treatment options in acral and mucosal melanomas by targeted genomic profiling.

Despite advancements in treating cutaneous melanoma, patients with acral and mucosal (A/M) melanomas still have limited therapeutic options and poor prognoses. We analyzed 156 melanomas (101 cutaneous, 28 acral, and 27 mucosal) using the Foundation One cancer-gene specific clinical testing platform and identified new, potentially targetable genomic alterations (GAs) in specific anatomic sites of A/M melanomas. Using novel pre-clinical models of A/M melanoma, we demonstrate that several GAs and corresponding oncogenic pathways associated with cutaneous melanomas are similarly targetable in A/M melanomas. Other alterations, including MYC and CRKL amplifications, were unique to A/M melanomas and susceptible to indirect targeting using the BRD4 inhibitor JQ1 or Src/ABL inhibitor dasatinib, respectively. We further identified new, actionable A/M-specific alterations, including an inactivating NF2 fusion in a mucosal melanoma responsive to dasatinib in vivo. Our study highlights new molecular differences between cutaneous and A/M melanomas, and across different anatomic sites within A/M, which may change clinical testing and treatment paradigms for these rare melanomas.

Exploratory assessment of the effect of systemic administration of soluble glycoprotein 130 on cognitive performance and chemokine levels in a mouse model of experimental traumatic brain injury.

Uncontrolled neuroinflammation mediates traumatic brain injury (TBI) pathology and impairs recovery. Interleukin-6 (IL-6), a pleiotropic inflammatory regulator, is associated with poor clinical TBI outcomes. IL-6 operates via classical-signaling through membrane-bound IL-6 receptor (IL-6R) and trans-signaling through soluble IL-6 receptor (s)IL-6R. IL-6 trans-signaling specifically contributes to neuropathology, making it a potential precision therapeutic TBI target. Soluble glycoprotein 130 (sgp130) prevents IL-6 trans-signaling, sparing classical signaling, thus is a possible treatment. Mice received either controlled cortical impact (CCI) (6.0 ± 0.2 m/s; 2 mm; 50-60ms) or sham procedures. Vehicle (VEH) or sgp130-Fc was subcutaneously administered to sham (VEH or 1 µg) and CCI (VEH, 0.25 µg or 1 µg) mice on days 1, 4, 7, 10 and 13 post-surgery to assess effects on cognition [Morris Water Maze (MWM)] and ipsilateral hemisphere IL-6 related biomarkers (day 21 post-surgery). CCI + sgp130-Fc groups (0.25 µg and 1 µg) were combined for analysis given similar behavior/biomarker outcomes. CCI + VEH mice had longer latencies and path lengths to the platform and increased peripheral zone time versus Sham + VEH and Sham + sgp130-Fc mice, suggesting injury-induced impairments in learning and anxiety. CCI + sgp130-Fc mice had shorter platform latencies and path lengths and had decreased peripheral zone time, indicating a therapeutic benefit of sgp130-Fc after injury on learning and anxiety. Interestingly, Sham + sgp130-Fc mice had shorter platform latencies, path lengths and peripheral zone times than Sham + VEH mice, suggesting a beneficial effect of sgp130-Fc, independent of injury. CCI + VEH mice had increased brain IL-6 and decreased sgp130 levels versus Sham + VEH and Sham + sgp130-Fc mice. There was no treatment effect on IL-6, sIL6-R or sgp130 in Sham + VEH versus Sham + sgp130-Fc mice. There was also no treatment effect on IL-6 in CCI + VEH versus CCI + sgp130-Fc mice. However, CCI + sgp130-Fc mice had increased sIL-6R and sgp130 versus CCI + VEH mice, demonstrating sgp130-Fc treatment effects on brain biomarkers. Inflammatory chemokines (MIP-1ß, IP-10, MIG) were increased in CCI + VEH mice versus Sham + VEH and Sham + sgp130-Fc mice. However, CCI + sgp130-Fc mice had decreased chemokine levels versus CCI + VEH mice. IL-6 positively correlated, while sgp130 negatively correlated, with chemokine levels. Overall, we found that systemic sgp130-Fc treatment after CCI improved learning, decreased anxiety and reduced CCI-induced brain chemokines. Future studies will explore sex-specific dosing and treatment mechanisms for sgp130-Fc therapy.

Social, not genetic, programming of development and stress physiology of a colonial seabird.

Phenotypic differences often stem from genetic/maternal differences and/or early-life adaptations to local environmental conditions. In colonial animals, little is known on how variation in the social environment is embedded into individual phenotypes, nor what the consequences are on individual fitness. We conducted an experimental cross-fostering study on king penguins (Aptenodytes patagonicus), exchanging eggs among 134 pairs breeding in high-density (67 pairs) or low-density (67 pairs) areas of the same breeding colony. We investigated differences in parent and chick phenotypes and survival in relation to the density of their origin and foster environment. Adults breeding in colony areas of high density exhibited decreased resting behaviour and increased aggression and vigilance, increased hypometabolism during incubation fasts, and more moderate corticosterone responses shaped by exposure to chronic stressors (e.g. constant aggression by neighbours). Chick phenotypes were more influenced by the environment in which they were raised than their genetic/maternal origin. Chicks raised in high-density colonial environments showed enhanced weight gain and survival rates regardless of the density of their genetic parents' breeding areas. Our study experimentally shows advantages to breeding in colonial areas of higher breeder densities in king penguins, and highlights the importance of social settings in shaping phenotype expression in colonial seabirds.

Naturalistic Bladder Filling Reveals Subtypes in Overactive Bladder Syndrome That Differentially Engages Urinary Urgency-Related Brain Circuits: Results From the Symptoms of Lower Urinary Tract Dysfunction Research Network (LURN).

PURPOSE: Overactive bladder (OAB) may be attributed to dysfunction in supraspinal brain circuits. Overactive bladder participants enrolled in the LURN (Symptoms of Lower Urinary Tract Dysfunction Research Network) study reported sensations of urinary urgency during a bladder-filling paradigm while undergoing brain functional MRI to map supraspinal dysfunction. MATERIALS AND METHODS: OAB participants and controls (CONs) completed 2 resting-state functional MRI scans following consumption of 350 mL water. Scans were conducted at fuller and emptier bladder states, interleaved with voiding. Urgency ratings (0-10) were assessed. Patterns of urgency during bladder filling were investigated using latent class trajectory models. Clusters of participants encompassing each pattern (ie, subtype) were derived from aggregated groups of OAB and CON independent of diagnosis. RESULTS: Two distinct patterns of urgency trajectories were revealed: first subtype with OAB and CON who were unresponsive to bladder filling (OAB-1 and CON-1) and second highly responsive subtype predominantly containing OAB (OAB-2). OAB-2 participants scored significantly higher on urinary symptoms but not pain or psychosocial measures. Neuroimaging analyses showed change in urgency due to both bladder filling and voided volume related to multiple loci of brain network connectivity in OAB-2, and in some cases, different than OAB-1 and/or CON-1. Sensorimotor to dorsomedial/dorsolateral prefrontal connectivity mediated the relationship between stimulus (voided volume) and percept (urgency) in OAB-2. CONCLUSIONS: Our results reveal different OAB subtypes with latent class trajectory models of urgency ratings during natural bladder filling. Functional MRI revealed differences in pathophysiology between subtypes, namely sensorimotor-prefrontal connectivity is a key locus in OAB patients with higher urinary symptoms.

Structural Changes in Brain White Matter Tracts Associated With Overactive Bladder Revealed by Diffusion Tensor Magnetic Resonance Imaging: Findings From a Symptoms of Lower Urinary Tract Dysfunction Research Network Cross-Sectional Case-Control Study.

PURPOSE: Our objective was to investigate structural changes in brain white matter tracts using diffusion tensor imaging (DTI) in patients with overactive bladder (OAB). MATERIALS AND METHODS: Treatment-seeking OAB patients and matched controls enrolled in the cross-sectional case-control LURN (Symptoms of Lower Urinary Tract Dysfunction Research Network) Neuroimaging Study received a brain DTI scan. Microstructural integrity of brain white matter was assessed using fractional anisotropy (FA) and mean diffusivity. OAB and urgency urinary incontinence (UUI) symptoms were assessed using the OAB Questionnaire Short-Form and International Consultation on Incontinence Questionnaire-Urinary Incontinence. The Lower Urinary Tract Symptoms Tool UUI questions and responses were correlated with FA values. RESULTS: Among 221 participants with evaluable DTI data, 146 had OAB (66 urinary urgency-only without UUI, 80 with UUI); 75 were controls. Compared with controls, participants with OAB showed decreased FA and increased mean diffusivity, representing greater microstructural abnormalities of brain white matter tracts among OAB participants. These abnormalities occurred in the corpus callosum, bilateral anterior thalamic radiation and superior longitudinal fasciculus tracts, and bilateral insula and parahippocampal region. Among participants with OAB, higher OAB Questionnaire Short-Form scores were associated with decreased FA in the left inferior fronto-occipital fasciculus, P < .0001. DTI differences between OAB and controls were driven by the urinary urgency-only (OAB-dry) but not the UUI (OAB-wet) subgroup. CONCLUSIONS: Abnormalities in microstructural integrity in specific brain white matter tracts were more frequent in OAB patients. More severe OAB symptoms were correlated with greater degree of microstructural abnormalities in brain white matter tracts in patients with OAB. TRIAL REGISTRATION: ClinicalTrials.gov: NCT02485808.

Bone health in women with premature ovarian insufficiency/early menopause: a 23-year longitudinal analysis.

STUDY QUESTION: What is the frequency of, and predictors for, osteoporosis, fractures, and osteoporosis management (investigation, treatment) in women with premature ovarian insufficiency (POI; menopause <40 years) and early menopause (EM; menopause 40-44years)? SUMMARY ANSWER: Over the 23-year follow-up duration, at a mean age of 68 years, women with POI/EM had higher osteoporosis/fracture risk and prevalence, higher osteoporosis screening and anti-osteoporosis medication use compared to women with usual age menopause; increasing age was predictive of increased risk of osteoporosis/fracture and menopause hormone therapy (MHT) prior to or at study entry (aged 45-50 years) was protective. WHAT IS KNOWN ALREADY: Women with POI/EM have increased risk of osteoporosis and fractures with limited data regarding risk factors for reduced bone density and fractures. Clinical guidelines recommend screening with dual X-ray absorptiometry (DXA) and treatment with MHT for most women with POI/EM to reduce osteoporosis and fracture risk; however, studies indicate gaps in osteoporosis knowledge, guideline uptake, and management adherence by clinicians and women. STUDY DESIGN, SIZE, DURATION: The Australian Longitudinal Study on Women's Health is a prospective longitudinal study of Australian women. This study uses the cohort of women born between 1946 and 1951, surveyed nine times between 1996 and 2019. Data from the Australian administrative health records, including hospital admissions data (fractures, osteoporosis), Medicare Benefits Schedule (DXA), and the Pharmaceutical Benefits Scheme (PBS; MHT, anti-osteoporosis medication, available only from 2002) were linked to survey data. PARTICIPANTS/MATERIALS, SETTING, METHODS: Survey respondents with self-reported age of menopause were included. POI/EM was defined as menopause <45 years. T-test or chi-square were used for comparisons at baseline (P < 0.05 indicates significance). Generalized estimating equations for panel data explored predictors for the longitudinal outcomes of osteoporosis, fractures, DXA rates, MHT use, and anti-osteoporosis medication (in women with osteoporosis/fracture, from Survey 4 onwards only). Univariable regression was performed, and variables retained where P < 0.2, to form the multivariable model, and bootstrapping with 100 repetitions at 95% sampling of the original dataset to ensure robustness of results. MAIN RESULTS AND THE ROLE OF CHANCE: Eight thousand six hundred and three women were included: 610 (7.1%) with POI/EM. Mean (SD) baseline age was 47.6 (1.45) years in the entire cohort and mean (SD) age of menopause was 38.2 (7.95) and 51.3 (3.04) years in women with POI/EM and usual age menopause, respectively (P < 0.001). Over the 23 years, of women with POI/EM, 303 (49.7%) had osteoporosis/fractures, 421 (69.0%) had DXA screening, 474 ever used MHT (77.7%), and 116 (39.1%) of those with osteoporosis/fractures used anti-osteoporosis medication. Of women with usual age menopause, 2929 (36.6%) had osteoporosis/fractures, 4920 (61.6%) had DXA screening, 4014 (50.2%) used MHT, and 964 (33.0%) of those with osteoporosis/fractures used anti-osteoporosis medication. Compared to women with menopause at age ≥45 years and after adjusting for other risk factors, women with POI/EM had increased risk of osteoporosis (odds ratio [OR] 1.37; 95% CI 1.07-1.77), fractures (OR 1.45; 1.15-1.81), DXA testing (OR 1.64; 1.42-1.90), MHT use (OR 6.87; 5.68-8.30), and anti-osteoporosis medication use (OR 1.50; 1.14-1.98). In women with POI/EM women, increasing age was associated with greater risk of osteoporosis/fracture (OR 1.09; 1.08-1.11), and MHT prior to or at study entry (aged 45-50 years), was protective (OR 0.65, 0.45-0.96). In women with POI/EM, age (OR 1.11; 1.10-1.12), fractures (OR 1.80, 1.38-2.34), current smoking (OR 0.60; 0.43-0.86), and inner (OR 0.68; 0.53-0.88) or outer regional (OR 0.63; 0.46-0.87) residential location were associated with DXA screening. In women with POI/EM, increasing age (OR 1.02; 1.01-1.02), and currently consuming alcohol (OR 1.17; 1.06-1.28), was associated with having ever used MHT. In the 299 women with POI/EM and osteoporosis/fractures, only 39.1% ever received treatment with an anti-osteoporosis medication. Increasing age (OR 1.07; 1.04-1.09) and lower BMI (OR 0.95; 0.92-0.98) were associated with greater likelihood of treatment with anti-osteoporosis medication. LIMITATIONS, REASONS FOR CAUTION: Survey data including age of menopause were self-reported by participants; fracture questions were not included in the 2001 survey, and location or level of trauma of self-reported fractures was not asked. Additional risk/protective factors such as vitamin D status, calcium intake, and exercise were not able to be included. Due to sample size, POI and EM were combined for all analyses, and we were unable to differentiate between causes of POI/EM. PBS data were only available from 2004, and hospital admissions data were state-based, with all of Australia were only available from 2007. WIDER IMPLICATIONS OF THE FINDINGS: This study supports previous literature indicating increased risk of osteoporosis and fractures in women with POI, and adds evidence for women with POI/EM, where there was a relative paucity of data. This is the first study to analyse a variety of clinical and demographic risk factors for osteoporosis and fractures in women with POI/EM, as well as analysing investigation and treatment rates. In these women, using MHT prior to or at study entry, aged 45-50 years, was protective for osteoporosis/fractures; however, having ever used MHT was not, highlighting the importance of early treatment with MHT in these women to preserve bone strength. Although women with POI/EM and osteoporosis or fractures were more likely to use anti-osteoporosis medications than those with usual age menopause, overall treatment rates are low at <40%, demonstrating a significant treatment gap that should be addressed to reduce future fracture risk. STUDY FUNDING/COMPETING INTEREST(S): This study was funded by The Australian NHMRC Centre of Research Excellence Women's Health in Reproductive Life (CRE-WHIRL, project number APP1171592). A.R.J. is the recipient of a National Health and Medical Research Council post-graduate research scholarship (grant number 1169192). P.R.E. is supported by a National Health and Medical Research Council grant 1197958. P.R.E. reports grants paid to their institution from Amgen, Sanofi, and Alexion, honoraria from Amgen paid to their institution, and honoraria from Alexion and Kyowa-Kirin. TRIAL REGISTRATION NUMBER: N/A.

Gram-negative anaerobes elicit a robust keratinocytes immune response with potential insights into HS pathogenesis.

Hidradenitis Suppurativa (HS) is a chronic autoinflammatory skin disease with activated keratinocytes, tunnel formation and a complex immune infiltrate in tissue. The HS microbiome is polymicrobial with an abundance of commensal gram-positive facultative (GPs) Staphylococcus species and gram-negative anaerobic (GNA) bacteria like Prevotella, Fusobacterium and Porphyromonas with increasing predominance of GNAs with disease severity. We sought to define the keratinocyte response to bacteria commonly isolated from HS lesions to probe pathogenic relationships between HS and the microbiome. Type strains of Prevotella nigrescens, Prevotella melaninogenica, Prevotella intermedia, Prevotella asaccharolytica, Fusobacterium nucleatum, as well as Staphylococcus aureus and the normal skin commensal Staphylococcus epidermidis were heat-killed and co-incubated with normal human keratinocytes. RNA was collected and analysed using RNAseq and RT-qPCR. The supernatant was collected from cell culture for protein quantification. Transcriptomic profiles between HS clinical samples and stimulated keratinocytes were compared. Co-staining of patient HS frozen sections was used to localize bacteria in lesions. A mouse intradermal injection model was used to investigate early immune recruitment. TLR4 and JAK inhibitors were used to investigate mechanistic avenues of bacterial response inhibition. GNAs, especially F. nucleatum, stimulated vastly higher CXCL8, IL17C, CCL20, IL6, TNF and IL36γ transcription in normal skin keratinocytes than the GPs S. epidermidis and S. aureus. Using RNAseq, we found that F. nucleatum (and Prevotella) strongly induced the IL-17 pathway in keratinocytes and overlapped with transcriptome profiles of HS patient clinical samples. Bacteria were juxtaposed to activated keratinocytes in vivo, and F. nucleatum strongly recruited murine neutrophil and macrophage migration. Both the TLR4 and pan-JAK inhibitors reduced cytokine production. Detailed transcriptomic profiling of healthy skin keratinocytes exposed to GNAs prevalent in HS revealed a potent, extensive inflammatory response vastly stronger than GPs. GNAs stimulated HS-relevant genes, including many genes in the IL-17 response pathway, and were significantly associated with HS tissue transcriptomes. The close association of activated keratinocytes with bacteria in HS lesions and innate infiltration in murine skin cemented GNA pathogenic potential. These novel mechanistic insights could drive future targeted therapies.

Characterization and Control of the Run-and-Tumble Dynamics of Escherichia Coli.

We characterize the full spatiotemporal gait of populations of swimming Escherichia coli using renewal processes to analyze the measurements of intermediate scattering functions. This allows us to demonstrate quantitatively how the persistence length of an engineered strain can be controlled by a chemical inducer and to report a controlled transition from perpetual tumbling to smooth swimming. For wild-type E. coli, we measure simultaneously the microscopic motility parameters and the large-scale effective diffusivity, hence quantitatively bridging for the first time small-scale directed swimming and macroscopic diffusion.

Sexual behavior among emerging adults in Africa: a systematic review and meta-analysis.

BACKGROUND: Estimates on sexual behavior (SB) among emerging adults (EmA) is varied in literature, which presents a challenge when designing targeted interventions. We aimed to summarize literature on prevalence and risk factors of SB among EmA in Africa. METHODS: A search for studies published in PubMed, Embase and Psych Info by March 2023 was done. Studies involving EmA (18-25 years), conducted in Africa and reporting one or more of seven SB were reviewed. Pooled prevalence estimates were summarized using forest plots. Heterogeneity in SB was explored. Risk factors were synthesized using a modified socio-ecological model. RESULTS: Overall, 143 studies were analyzed. Non-condom use had the highest pooled prevalence (47% [95% CI: 42-51]), followed by study-defined SB (37% [95% CI: 25-50]) and concurrency (37% [95% CI: 21-54]), multiple sex partners (31% [95% CI: 25-37]), younger age at sexual debut (26% [95% CI: 20-32]), age disparate relationships (24% [95% CI: 17-32]) and transactional sex (19% [95% CI: 13-26]). Heterogeneity was partially explained by sex, with female participants having higher pooled prevalence estimates compared to their male counterparts. In four of the seven outcomes, alcohol/drug use was the most common risk factor. CONCLUSIONS: SB was common among EmA and differentially higher in emerging female adults. Non-condom use had the highest pooled prevalence, which may contribute to the transmission of HIV and other sexually transmitted infections (STIs). Interventions targeting emerging female adults and alcohol/drug use may reduce SB, which may in-turn mitigate transmission of HIV and other STIs among EmA in Africa.

Correction: Sizing multimodal suspensions with differential dynamic microscopy.

Correction for 'Sizing multimodal suspensions with differential dynamic microscopy' by Joe J. Bradley et al., Soft Matter, 2023, 19, 8179-8192, https://doi.org/10.1039/D3SM00593C.

Sunscreens Part 2: Regulation and Safety.

The second part of this CME article discusses sunscreen regulation and safety considerations for humans and the environment. First, we provide an overview of the history of the United States Food and Drug Administration's regulation of sunscreen. Recent Food and Drug Administration studies clearly demonstrate that organic ultraviolet filters are systemically absorbed during routine sunscreen use, but to date there is no evidence of associated negative health effects. We also review the current evidence of sunscreen's association with vitamin D levels and frontal fibrosing alopecia, and recent concerns regarding benzene contamination. Finally, we review the possible environmental effects of ultraviolet filters, particularly coral bleaching. While climate change has been shown to be the primary driver of coral bleaching, laboratory-based studies suggest that organic ultraviolet filters represent an additional contributing factor, which led several localities to ban certain organic filters.

Sunscreens Part 1: Mechanisms and Efficacy.

As our knowledge of the harmful effects of ultraviolet radiation continues to evolve, sunscreen remains an integral part of a comprehensive photoprotection strategy against multiple endpoints of ultraviolet-mediated damage. Part 1 of this review covers sunscreen active and additive ingredient properties, mechanisms of action and gaps in coverage. Following an overview of sunscreen's efficacy in protecting against sunburn, photocarcinogenesis, photoaging, pigmentary disorders, and idiopathic photodermatoses, we highlight considerations for product use and selection in children and individuals with skin of color.

Population density and vegetation resources influence demography in a hibernating herbivorous mammal.

Demography of herbivorous mammal populations may be affected by changes in predation, population density, harvesting, and climate. Whereas numerous studies have focused on the effect of single environmental variables on individual demographic processes, attempts to integrate the consequences of several environmental variables on numerous functional traits and demographic rates are rare. Over a 32-year period, we examined how forage availability (vegetation assessed through NDVI) and population density affected the functional traits and demographic rates of a population of Columbian ground squirrels (Urocitellus columbianus), a herbivorous hibernating rodent. We focused on mean population phenology, body mass, breeding success, and survival. We found a negative effect of population density on demographic rates, including on breeding success and pup and adult survival to the next year. We found diverging effects of vegetation phenology on demographic rates: positive effects of a later start of the growing season on adult and yearling female survival, and juvenile survival, but no clear effect on male survival. Interestingly, neither population density nor vegetation affected population phenology or body condition in the following year. Vegetative growth rate had a positive influence on female mass gain (somatic investment) over a season, but both vegetative growth rate and biomass, surprisingly, had negative effects on the survival of young through their first hibernation. Thus, ground squirrels appeared to benefit more from later timing of vegetation than increases in vegetative biomass per se. Our study provides evidence for complex ecological effects of vegetation and population density on functional traits and demographic rates of small mammal populations.

High prevalence of gastrointestinal disorders in a large cohort of patients with joint hypermobility.

The gastrointestinal (GI) manifestations in children with hypermobile Ehlers-Danlos syndrome/joint hypermobility syndrome (hEDS/JHS) are not well described. We investigated the prevalence of GI disorders in children and young adults with hEDS/JHS through a single-center retrospective review. Demographic data, clinical history, symptoms, and diagnostic studies were reviewed. Of 435 patients with hEDS/JHS, 66% were females (age 5-28 years). We noted a high prevalence of constipation (61%), dysphagia (32%), dyspepsia and/or gastroparesis (25%), eosinophilic esophagitis (EoE) (21%), and celiac disease (4%) in our cohort. Upper endoscopy and gastric emptying scans had the highest yield to detect abnormalities. Motility studies were abnormal in 31% of the 80 patients who underwent them. Dysphagia symptoms are significantly associated with EoE. Thirty-three percent of dysphagia patients had EoE, versus 16% of non-dysphagia patients (p < 0.001). Screening hEDS/JHS patients for GI issues should be routine, with further investigations and referrals guided by identified symptoms.

Unusual Sesquiterpenes from Streptomyces olindensis DAUFPE 5622.

In nature, the vast majority of sesquiterpenes are produced by type I mechanisms, and glycosylated sesquiterpenes are rare in actinobacteria. Streptomyces olindensis DAUFPE 5622 produces the sesquiterpenes olindenones A-G, a new class of rearranged drimane sesquiterpenes. Olindenones B-D are oxygenated derivatives of olindenone A, while olindenones E-G are analogs glycosylated with dideoxysugars. 13C-isotope labeling studies demonstrated olindenone A biosynthesis occurs via the methylerythritol phosphate (MEP) pathway and suggested the rearrangement is only partially concerted. Based on the structures, one potential mechanism of olindenone A formation proceeds by cyclization of the linear terpenoid precursor, likely occurring via a terpene cyclase-mediated type II mechanism whereby the terminal alkene of the precursor is protonated, triggering carbocation-driven cyclization followed by rearrangement. Diphosphate hydrolysis may occur either before or after cyclization. Although a biosynthetic route is proposed, the terpene cyclase gene responsible for producing olindenones currently remains unidentified.