UC Riverside

Global groundwater depletion is a pressing issue, particularly in regions dependent on groundwater for agriculture. Agricultural Managed Aquifer Recharge (Ag-MAR), where farm fields are used as spreading grounds for flood water, is a promising strategy to replenish groundwater, but it raises concerns about pesticide leaching into aquifers, posing risks to both drinking water quality and ecosystems. This study employs a physically based unsaturated flow model, a Bayesian probabilistic approach and novel towed transient electromagnetic (tTEM) data to determine the fate and transport, especially the maximum transport depths (MTDs) of four pesticide residues (Imidacloprid, Thiamethoxam, Chlorantraniliprole, and Methoxyfenozide) in three 70-m-thick unsaturated zones (P1, P2, P3) of California's Central Valley alluvial aquifer. The results show that Ag-MAR significantly increased MTDs across all profiles for all pesticides and with higher variability in pesticide transport depths compared to the natural rainfall scenario. Profile P2, with the highest sand content exhibited the deepest MTDs under Ag-MAR, indicating a strong influence of soil texture on pesticide transport. While natural capillary barriers at the depth of 2.5-20 m impede water flow under natural rainfall conditions, the high-pressure infiltration during Ag-MAR overcomes these barriers, leading to deeper water and pesticide movement. Among various evaluated pesticides, Methoxyfenozide exhibited the smallest absolute MTDs but the largest relative increases in MTDs (RMTDs) under Ag-MAR due to its persistence and low mobility, posing a higher risk of deep transport during intensive recharge events. In contrast, Thiamethoxam showed the largest MTDs under both scenarios but smaller RMTDs due to its high mobility, suggesting a more consistent transport behavior regardless of recharge practices. The findings highlight the importance of understanding both site-specific and pesticide-specific behaviors to mitigate groundwater contamination risks during large water applications.

Systems hosting multiple giant planets are important laboratories for understanding planetary formation and migration processes. We present a nearly decade-long Doppler spectroscopy campaign from the HIRES instrument on the Keck-I telescope to characterize the two transiting giant planets orbiting Kepler-511 on orbits of 27 days and 297 days. The radial velocity measurements yield precise masses for both planets: 0.10 0 − 0.039 + 0.036 (2.6σ) and 0.4 4 − 0.12 + 0.11 (4σ) Jupiter masses, respectively. We use these masses to infer their bulk metallicities (i.e., metal mass fraction 0.87 ± 0.03 and 0.22 ± 0.04, respectively). Strikingly, both planets contain approximately 25-30 Earth masses of heavy elements but have very different amounts of hydrogen and helium. Envelope mass loss cannot account for this difference due to the relatively large orbital distance and mass of the inner planet. We conclude that the outer planet underwent runaway gas accretion while the inner planet did not. This bifurcation in accretion histories is likely a result of the accretion of gas with very different metallicities by the two planets or the late formation of the inner planet from a merger of sub-Neptunes. Kepler-511 uniquely demonstrates how giant planet formation can produce dramatically different outcomes even for planets in the same system.

BACKGROUND: Evolution has shaped diverse reproductive investment strategies, with some organisms integrating environmental cues into their reproductive decisions. In animal societies, social cues can further influence reproductive decisions in ways that might support the survival and success of the social group. Bumble bees are a lineage of eusocial insects wherein queens initiate nests independently. Bumble bee queens enter their eusocial phase only after successfully rearing their first offspring and thereafter exhibit an increased rate of egg-laying. We tested the idea that during bumble bee nest initiation, queen reproduction is socially context-dependent and under the control of social conditions in the nest. RESULTS: Our findings reveal that in the bumble bee Bombus impatiens, queen egg-laying follows a dynamic, stereotypical pattern and is also heavily influenced by social group members. During the initial stages of nest initiation, accelerated egg-laying in queens is associated with the presence of workers or older larvae and pupae. Moreover, workers are required for queens to maintain increased levels of egg laying across the nest initiation stage. We also confirmed a previously-described pattern where queens temporarily decelerate egg-laying early in nest-founding, only to increase it again when the first adult workers are soon to emerge. This pause in egg-laying was observed in all B. impatiens queens as well as in additional species examined. CONCLUSIONS: Our results support the idea that eusocial systems can employ socially context-dependent control of queen egg-laying as a reproductive strategy. In some solitary-founding lineages, including bumble bees, queens may reach their full reproductive potential only after the emergence of the first adult workers, who then take over brood care. This stands in contrast to the hyper-reproductivity observed in some eusocial species. The presence of workers and older brood (who will soon eclose) not only alleviates queen brood care responsibilities but may also provide signals that cause queens to increase their reproductive output. These phenomena may allow queens to adapt their reproductive output to the conditions of the colony. Broadly, these findings highlight the dynamic interplay between social conditions and reproduction in bumble bees.

The purpose of this study was to explore and document the migratory motivations and reasonings of Mexican mothers of autistic children pursuing autism services in the United States. The study was guided by the overarching research question, "What are the experiences of mothers living in the U.S./Mexico border while seeking services for their autistic children, and what social and financial resources influence their decisions?". Following a Community-Based Participatory Research approach, we collaborated with organizations and stakeholders in the development of qualitative research materials while also supporting the purposeful recruitment of caregivers who: (1) had lived in the U.S./Mexico border and moved to the United States to pursue autism services, or (2) were currently living in the U.S./Mexico border and were looking to pursue autism services in the United States. Eleven mothers participated in a two-part semi-structured interview protocol alongside a demographic form. Findings outline three global themes that describe the dynamic process of pursuing autism services and migrating to the United States: (1) stage of constant contrast between Mexico and the United States, (2) active pursuit of autism services in the United States, and (3) potential pathways to immigration. The global themes provide a systemic analysis and reflection of the current autism service system in Mexico while also highlighting the gaps in service coordination for first-generation immigrant families.Lay abstractThis study aimed to understand why Mexican mothers of autistic children move to the United States to seek autism services. Using a method that involved the community, we worked with local partners to create research materials and find caregivers for the study. We focused on mothers who had either moved from the U.S./Mexico border to the United States for autism services or were planning to do so. Eleven mothers participated by completing a two-part interview and a demographic form. The results highlight three main themes that explain the complex reasons and motivations behind their decision to seek autism services in the United States: (1) stage of constant contrast between Mexico and the United States, (2) active pursuit of autism services in the United States, and (3) potential pathways to immigration. These findings also highlight the differences in autism services between the United States and Mexico and the challenges faced by immigrant families trying to get the care their children need.

Anemia is the most common extraintestinal manifestation of inflammatory bowel disease (IBD). Iron deficiency is the most frequent cause of anemia in IBD; however, the mechanisms involved are still poorly understood. Here, we investigated the role of the IBD risk gene, protein tyrosine phosphatase non-receptor type 2 (PTPN2), in regulating iron homeostasis. Proteomic analyses were performed on serum from IBD patients genotyped for the IBD-associated loss-of-function rs1893217 PTPN2 variant. Constitutive Ptpn2 wild type (WT), heterozygous (Het), and knockout (KO) mice were analyzed for iron content, blood parameters, and expression of iron handling proteins. Iron absorption was assessed through radiotracer assays. Serum proteomic analyses revealed that the iron homeostasis signaling pathway was the main pathway downregulated in Crohns disease (CD) patients carrying the PTPN2 risk allele, independent of disease activity. Ptpn2-KO mice showed characteristics of anemia, including reduced hemoglobin concentrations along with serum and tissue iron deficiency and elevated serum hepcidin levels vs. Ptpn2-WT and Het mice. 55Fe absorption via oral gavage was significantly impaired in Ptpn2-KO mice. Correspondingly, Ptpn2-KO mice showed reduced apical membrane expression of the iron transporter DMT1. CD patients with the PTPN2 loss-of-function rs1893217 variant display alterations in serum iron handling proteins. Loss of Ptpn2 in mice caused features of anemia, including iron deficiency associated with reduced apical membrane expression of DMT1. These findings identify an important role for PTPN2 in regulating systemic iron homeostasis.

Microbial environmental transmission among individuals plays an important role in shaping the microbiomes of many species. Despite the importance of the microbiome for host fitness, empirical investigations on environmental transmission are scarce, particularly in systems where interactions across multiple trophic levels influence symbiotic dynamics. Here, we explore microbial transmission within insect microbiomes, focusing on solitary bees. Specifically, we investigate the environmental transmission hypothesis, which posits that solitary bees acquire and deposit their associated microbiota from and to their surroundings, especially flowers. Using experimental setups, we examine the transmission dynamics of Apilactobacillus micheneri, a fructophilic and acidophilic bacterium, between the solitary bee Osmia lignaria (Megachilidae) and the plant Phacelia tanacetifolia (Boraginaceae). Our results demonstrate that bees not only acquire bacteria from flowers but also deposit these microbes onto uninoculated flowers for other bees to acquire them, supporting a bidirectional microbial exchange. We therefore find empirical support for the environmental transmission hypothesis, and we discuss the multitrophic dependencies that facilitate microbial transmission between bees and flowers.

The use of timber harvesting and skidding machines significantly alters a catchment's hydrological processes due to soil compaction effects. Although it is obvious that the use of heavy forest machines increases surface runoff and water yield, quantifying these effects remains challenging. This research aimed at exploring how physically based hydrological models are suited for investigating the effects of soil compaction on hydrologic responses at the catchment scale. We employed a process-based SWAT+ hydrological model to assess the impact of temporary (e.g., skid trails) and more permanent timber harvest infrastructure on the hydrologic response of the Palatinate Forest Biosphere Reserve in Germany. We specifically analysed the role of soil compaction in hydrological processes by simulating water fluxes under three scenarios: uncompacted soil (baseline), compacted soil during harvest and skidding operations (Scenario-1) and due to permanently constructed infrastructures (Scenario-2). Results demonstrated substantial alterations in water fluxes under Scenarios-1 and -2 compared to the baseline, with annual average surface runoff increasing by 74% and 125%, respectively, and lateral flow decreasing by 14% and 26%. These changes varied notably between steep and low slope areas. Steep slope regions exhibited significantly larger increases in surface runoff, while low slope areas experienced greater reductions in lateral flow and percolation. This differentiation underlines the combined influence of management scenarios and slope, highlighting the critical need for forest harvesting strategies that account for spatial variability and the types of machinery employed.

The reuse of treated wastewater (TWW) for irrigation alleviates freshwater (FW) scarcity while supporting a circular economy. However, the potential human exposure to contaminants of emerging concern (CECs) through plant accumulation is a significant barrier. Currently, knowledge on CEC contamination of edible produce and effective mitigation strategies for the safe reuse of TWW is limited, particularly under field conditions. This study examined the accumulation of a representative set of CECs, including perfluoroalkyl and polyfluoroalkyl substances (PFAS), pharmaceuticals and personal care products, and tire wear particle (TWP) chemicals, in radish, lettuce, and tomato under three irrigation practices: FULL (continuous TWW irrigation), HALF (midseason switch from TWW to FW), and FW-only. Despite low PFAS concentrations (8.1-25.7 ng/L) in TWW, the plant uptake was consistently observed, including in tomato fruits. Alternating TWW with FW significantly reduced CEC accumulation in edible tissues, particularly for compounds with short half-lives, with reductions up to 82.4% even for persistent PFAS. For most CECs and plant species, edible tissue concentrations were similar between the HALF and FW treatments. These findings demonstrate the on-farm applicability of simple irrigation modifications to reduce food contamination and contribute to the promotion of safe reuse of nonconventional waters.

Ribonucleases (RNases) are ubiquitous enzymes that process or degrade RNA, essential for cellular functions and immune responses. The EndoU-like superfamily includes endoribonucleases conserved across bacteria, eukaryotes, and certain viruses, with an ancient evolutionary link to the ribonuclease A-like superfamily. Both bacterial EndoU and animal RNase A share a similar fold and function independently of cofactors. In contrast, the eukaryotic EndoU catalytic domain requires divalent metal ions for catalysis, possibly due to an N-terminal extension near the catalytic core. In this study, we use biophysical and computational techniques along with in vitro assays to investigate the calcium-dependent activation of human EndoU. We determine the crystal structure of EndoU bound to calcium and find that calcium binding remote from the catalytic triad triggers water-mediated intramolecular signaling and structural changes, activating the enzyme through allostery. Calcium binding involves residues from both the catalytic core and the N-terminal extension, indicating that the N-terminal extension interacts with the catalytic core to modulate activity in response to calcium. Our findings suggest that similar mechanisms may be present across all eukaryotic EndoUs, highlighting a unique evolutionary adaptation that connects endoribonuclease activity to cellular signaling in eukaryotes.

A comparative study of two grapevine rootstocks with contrasting drought stress responses revealed that the drought-resilient RUG harbors an efficient antioxidant defense system, characterized by increased activities of superoxide dismutase (SOD), glutathione peroxidase (GPX), and catalase (CAT), along with elevated proline (Pro) levels compared to the drought-sensitive MGT. This robust scavenging machinery enables RUG to maintain redox balance, effectively mitigating oxidative stress and preserving cellular integrity during drought. Anatomical evaluations showed severe xylem disruptions in MGT, including extensive tylosis, leading to leaf necrosis and impaired water transport. Conversely, RUG maintained a structurally intact and functional xylem, crucial for sustaining hydraulic conductivity and water supply during drought. The pronounced rise in Pro underscores its critical role in drought resilience, working synergistically with other cellular components to facilitate osmotic adjustment while detoxifying reactive oxygen species (ROS) and minimizing oxidative damage. Transcriptome profiling suggested that RUG displays sequential gene expression during drought driven by distinct molecular processes for photosynthesis, osmotic adjustment, and structural remodeling, a dynamic notably absent in MGT. These findings emphasize the complex interplay of osmotic and oxidative homeostasis in RUG, illustrating the adaptive mechanisms that contribute to its drought resilience, potentially guiding future rootstock selection and breeding strategies.