Biology subjects

Peters, J. R.

Publications and source records attributed to Peters, J. R..

3 recordsLinked to original sources

bioRxiv2024

Maturing giant kelp develop depth-specific microbiomes

Giant kelp (Macrocystis pyrifera) is a photosynthetic macroalga that produces dissolved organic carbon (DOC), essential for marine bacteria and food webs. The bacterial communities residing on giant kelp blades consume and compete for complex carbohydrates, contributing to the microbiome community structure. In this study, we investigate how the microbiome changes in response to the age and depth of giant kelp blades and assess how these changes relate to differences in the hosts photophysiology. We find that the microbial community increases in richness and evenness as kelp blades age. While the microbiomes of juvenile blades are stochastic, communities on mature blades coalesce into less variable, depth-specific community types. Differentially abundant genera in mature microbiomes include members of Bacteroidia and Gammaproteobacteria, known for carbohydrate degradation, and Planctomycetes, which often produce protective secondary metabolites. These shifts in microbiome communities are associated with increased maximum quantum yield of photosystem II of mature blades; therefore, they may be linked to enhanced DOC exudation. By shedding light on these dynamics, our study contributes to a better understanding of the complex interplay between macroalgae, their respective microbiomes, and the surrounding marine environment.

microbiology↗

bioRxiv2018

Differential Effects of the Menstrual Cycle on Reactive and Proactive Aggression in Borderline Personality Disorder

Borderline personality disorder (BPD) is characterized by rapidly shifting symptoms, including intense anger and aggressive behavior. Understanding how fluctuations in ovarian hormones across the menstrual cycle may contribute to symptom instability is key for accurate assessment of BPD symptoms and effective interventions. Reactive and proactive aggression, as well as anger in and out, were assessed daily in 15 physically healthy, unmedicated naturally cycling female individuals without dysmenorrhea meeting criteria for BPD across 35 days. Urine LH surge and salivary progesterone were used to confirm ovulation and verify cycle phase. Cyclical worsening of symptoms was evaluated using multilevel models to evaluate symptom differences between cycle phases. Both forms of aggressive behavior demonstrated marked cycle effects, with reactive aggression highest during perimenstrual cycle phases, co-occurring with increases in anger in and out. In contrast, highest levels of proactive aggression were observed during the follicular and ovulatory phases, when emotional symptoms and anger were otherwise at lowest levels. These findings highlight the importance of identifying the function of aggression when considering potential psychological and biological influences. Naturally cycling individuals with BPD may be at elevated risk for perimenstrual worsening of a range of interpersonally reactive symptoms, including reactive aggression, whereas proactive aggression may occur more in phases characterized by less emotional and cognitive vulnerability and greater reward sensitivity. Research on aggression in this population should consider cycle effects. Cycling individuals with BPD attempting to reduce aggressive behavior may benefit from cycle-tracking to increase awareness of these effects and to develop appropriate strategies.

neuroscience↗

bioRxiv2017

Perimenstrual Symptom Exacerbation in Borderline Personality Disorder: Evidence from Multilevel Models and the Carolina Premenstrual Assessment Scoring System

BackgroundIndividuals with borderline personality disorder (BPD) suffer from a constellation of rapidly shifting emotional, interpersonal, and behavioral symptoms. The menstrual cycle may contribute to symptom instability among females with this disorder.\n\nMethodsFifteen healthy, unmedicated females with BPD and without dysmenorrhea reported daily symptoms across 35 days. Urine luteinizing hormone (LH) and salivary progesterone (P4) were used to confirm ovulation and cycle phase. Cyclical worsening of symptoms was evaluated using (1) phase contrasts in multilevel models and (2) the Carolina Premenstrual Assessment Scoring System (C-PASS; Eisenlohr-Moul et al., 2017b), a protocol for evaluating clinically significant cycle effects on symptoms.\n\nResultsMost symptoms demonstrated midluteal worsening, a perimenstrual peak, and resolution of symptoms in the follicular or ovulatory phase. Post-hoc correlations with person-centered progesterone revealed negative correlations with most symptoms. Depressive symptoms showed an unexpected delayed pattern in which baseline levels of symptoms were observed in the ovulatory and midluteal phases, and exacerbations were observed during both the perimenstrual and follicular phases. The majority of participants met C-PASS criteria for clinically significant (>=30%) symptom exacerbation. All participants met the emotional instability criterion of BPD, and no participant met DSM-5 criteria for premenstrual dysphoric disorder (PMDD).\n\nConclusionsFemales with BPD may be at elevated risk for perimenstrual worsening of emotional symptoms. Longitudinal studies with fine-grained hormonal measurement as well as hormonal experiments are needed to determine the pathophysiology of perimenstrual exacerbation in BPD.

neuroscience↗