Relation of Riparian Buffer Strips to In-Stream Habitat, Macroinvertebrates and Fish in a Small Iowa Stream

Macroinvertebrate and fish habitat is often degraded as a result of agriculture. Riparian buffer strips are commonly used to counteract the negative effects of agriculture in headwater streams. We assessed the relation of multi-aged riparian buffer strips to in-stream habitat, macroinvertebrate and fish assemblages in an Iowa stream. In-stream habitat, macroinvertebrates, and fish were sampled from two buffered sites and two unbuffered sites, with the greatest substrate, water depth, and velocity heterogeneity occurring in buffered sites. The highest macroinvertebrate richness (11) as well as fish species richness (14), diversity (1.99) and IBI score (3 7) were found in the site buffered the longest. Habitat heterogeneity and fish community richness and diversity were greater in buffered sites than unbuffered sites making them possible indicators with which short-term stream recovery can be measured

Relation of Riparian Buffer Strips to In-Stream Habitat, Macroinvertebrates and Fish in a Small Iowa Stream

Macroinvertebrate and fish habitat is often degraded as a result of agriculture. Riparian buffer strips are commonly used to counteract the negative effects of agriculture in headwater streams. We assessed the relation of multi-aged riparian buffer strips to in-stream habitat, macroinvertebrate and fish assemblages in an Iowa stream. In-stream habitat, macroinvertebrates, and fish were sampled from two buffered sites and two unbuffered sites, with the greatest substrate, water depth, and velocity heterogeneity occurring in buffered sites. The highest macroinvertebrate richness (11) as well as fish species richness (14), diversity (1.99) and IBI score (37) were found in the site buffered the longest. Habitat heterogeneity and fish community richness and diversity were greater in buffered sites than unbuffered sites making them possible indicators with which shortterm stream recovery can be measured

Relation of Riparian Buffer Strips to In-Stream Habitat, Macroinvertebrates and Fish in a Small Iowa Stream

Macroinvertebrate and fish habitat is often degraded as a result of agriculture. Riparian buffer strips are commonly used to counteract the negative effects of agriculture in headwater streams. We assessed the relation of multi-aged riparian buffer strips to in-stream habitat, macroinvertebrate and fish assemblages in an Iowa stream. In-stream habitat, macroinvertebrates, and fish were sampled from two buffered sites and two unbuffered sites, with the greatest substrate, water depth, and velocity heterogeneity occurring in buffered sites. The highest macroinvertebrate richness (11) as well as fish species richness (14), diversity (1.99) and IBI score (37) were found in the site buffered the longest. Habitat heterogeneity and fish community richness and diversity were greater in buffered sites than unbuffered sites making them possible indicators with which short-term stream recovery can be measured

Variation in chronic nicotinamide treatment after traumatic brain injury can alter components of functional recovery independent of histological damage

Previously, we have shown that the window of opportunity for nicotinamide (NAM) therapy (50 mg/kg) following cortical contusion injuries (CCI) extended to 4–8 hrs post-CCI when administered over a six day post-CCI interval. The purpose of the present study was to determine if a more chronic NAM treatment protocol administered following CCI would extend the current window of opportunity for effective treatment onset. Groups of rats received either unilateral CCI's or sham procedures. Initiation of NAM therapy (50 mg/kg, ip) began at either 15-min, 4-hrs, 8-hrs or 24-hrs post-injury. All groups received daily systemic treatments for 12 days post-CCI at 24 hr intervals. Behavioral assessments were conducted for 28 days post injury and included: vibrissae forelimb placing, bilateral tactile adhesive removal, forelimb asymmetry task and locomotor placing testing. Behavioral analysis on both the tactile removal and locomotor placing tests showed that all NAM-treated groups facilitated recovery of function compared to saline treatment. However, on the vibrissae-forelimb placing and forelimb asymmetry tests only the 4-hr and 8-hr NAM-treated groups were significantly different from the saline-treated group. The lesion analysis showed that treatment with NAM out to 8 hrs post-CCI significantly reduced the size of the injury cavity. The window of opportunity for NAM treatment is task-dependent and in some situations can extend to 24 hrs post-CCI. These results suggest that a long term treatment regimen of 50 mg/kg of NAM starting at the clinically relevant time points may prove efficacious in human TBI

Regulatory dendritic cell treatment prevents the development of vasopressin-induced preeclampsia

The concept that persistent feto-placental intolerance is important in the pathogenesis of preeclampsia (PE) has been demonstrated by our lab and others. Arginine vasopressin (AVP) infusion during pregnancy induces cardiovascular, renal, and immune alterations in mice consistent with human PE. These findings identify AVP as a potential contributor to poor fetal tolerance and the development of PE. In addition to their conventional immuno-stimulatory role, dendritic cells (DCs) also play a vital role in immune tolerance. In contrast to conventional DCs, regulatory DCs (DCregs) express low levels of co-stimulatory markers, produce anti-inflammatory cytokines, induce T regulatory cells, and promote tolerance. In mice, DCregs are able to prevent pro-inflammatory responses and induce antigen-specific tolerance. Given these known functions of DCregs, we hypothesize that DCregs will prevent the development of AVP-induced PE

Betamethasone: a novel therapeutic intervention for preeclampsia

The early pathogenesis of preeclampsia (PE) involves a systemic inflammatory immune response. Recent data demonstrate that increased circulating arginine vasopressin (AVP) in humans is predictive of PE and that infusion of AVP in mouse dams phenocopies the pregnancy-specific cardiovascular and immune alterations observed in human PE. Specifically, AVP suppresses anti-inflammatory cytokines and cells. Betamethasone (BMTZ), commonly given to women at risk for preterm birth, is both an AVP and immune response modulator. We hypothesize that early treatment with BMTZ will prevent the development of AVP-induced PE

Phylogenetic analysis of SARS-CoV-2 in the Boston area highlights the role of recurrent importation and superspreading events [preprint]

SARS-CoV-2 has caused a severe, ongoing outbreak of COVID-19 in Massachusetts with 111,070 confirmed cases and 8,433 deaths as of August 1, 2020. To investigate the introduction, spread, and epidemiology of COVID-19 in the Boston area, we sequenced and analyzed 772 complete SARS-CoV-2 genomes from the region, including nearly all confirmed cases within the first week of the epidemic and hundreds of cases from major outbreaks at a conference, a nursing facility, and among homeless shelter guests and staff. The data reveal over 80 introductions into the Boston area, predominantly from elsewhere in the United States and Europe. We studied two superspreading events covered by the data, events that led to very different outcomes because of the timing and populations involved. One produced rapid spread in a vulnerable population but little onward transmission, while the other was a major contributor to sustained community transmission, including outbreaks in homeless populations, and was exported to several other domestic and international sites. The same two events differed significantly in the number of new mutations seen, raising the possibility that SARS-CoV-2 superspreading might encompass disparate transmission dynamics. Our results highlight the failure of measures to prevent importation into MA early in the outbreak, underscore the role of superspreading in amplifying an outbreak in a major urban area, and lay a foundation for contact tracing informed by genetic data

Alternative-NHEJ Is a Mechanistically Distinct Pathway of Mammalian Chromosome Break Repair

Characterizing the functional overlap and mutagenic potential of different pathways of chromosomal double-strand break (DSB) repair is important to understand how mutations arise during cancer development and treatment. To this end, we have compared the role of individual factors in three different pathways of mammalian DSB repair: alternative-nonhomologous end joining (alt-NHEJ), single-strand annealing (SSA), and homology directed repair (HDR/GC). Considering early steps of repair, we found that the DSB end-processing factors KU and CtIP affect all three pathways similarly, in that repair is suppressed by KU and promoted by CtIP. In contrast, both KU and CtIP appear dispensable for the absolute level of total-NHEJ between two tandem I-SceI–induced DSBs. During later steps of repair, we find that while the annealing and processing factors RAD52 and ERCC1 are important to promote SSA, both HDR/GC and alt-NHEJ are significantly less dependent upon these factors. As well, while disruption of RAD51 causes a decrease in HDR/GC and an increase in SSA, inhibition of this factor did not affect alt-NHEJ. These results suggest that the regulation of DSB end-processing via KU/CtIP is a common step during alt-NHEJ, SSA, and HDR/GC. However, at later steps of repair, alt-NHEJ is a mechanistically distinct pathway of DSB repair, and thus may play a unique role in mutagenesis during cancer development and therapy

A Linear Framework for Time-Scale Separation in Nonlinear Biochemical Systems

Cellular physiology is implemented by formidably complex biochemical systems with highly nonlinear dynamics, presenting a challenge for both experiment and theory. Time-scale separation has been one of the few theoretical methods for distilling general principles from such complexity. It has provided essential insights in areas such as enzyme kinetics, allosteric enzymes, G-protein coupled receptors, ion channels, gene regulation and post-translational modification. In each case, internal molecular complexity has been eliminated, leading to rational algebraic expressions among the remaining components. This has yielded familiar formulas such as those of Michaelis-Menten in enzyme kinetics, Monod-Wyman-Changeux in allostery and Ackers-Johnson-Shea in gene regulation. Here we show that these calculations are all instances of a single graph-theoretic framework. Despite the biochemical nonlinearity to which it is applied, this framework is entirely linear, yet requires no approximation. We show that elimination of internal complexity is feasible when the relevant graph is strongly connected. The framework provides a new methodology with the potential to subdue combinatorial explosion at the molecular level