Stream Fish Assemblages Around the Clemson Experimental Forest

The southeastern USA harbors high aquatic diversity in the temperate region. Yet, stream fish suffer high imperilment rates due to anthropogenic activities such as habitat loss and water quality degradation. From the biodiversity conservation perspective, it is important to document what and where species occur in a landscape. The purpose of this Creative Inquiry project was to survey stream fish assemblages in and around the Clemson Experimental Forest. We surveyed local streams using electrofishing and seining techniques in Fall 2014 and recorded abundance of fish species captured. We collected common species such as bluehead chub (Nocomis leptocephalus) and yellowfin shiner (Notropis lutipinnis), as well as locally rare species such as blackbanded darter (Percina nigrofasciata). Although we hypothesized that larger streams would contain higher species richness than smaller streams, our data did not support this hypothesis based on a linear regression analysis. Our study showed that fish fauna around campus is diverse and we should be aware of these important water resources for conservation

Estimating size-specific brook trout abundance in continuously sampled headwater streams using Bayesian mixed models with zero inflation and overdispersion

Abstract -We examined habitat factors related to reach-scale brook trout Salvelinus fontinalis counts of four size classes in two headwater stream networks within two contrasting summers in Connecticut, USA. Two study stream networks (7.7 and 4.4 km) were surveyed in a spatially continuous manner in their entirety, and a set of Bayesian generalised linear mixed models was compared. Trout abundance was best described by a zero-inflated overdispersed Poisson model. The effect of habitat covariates was not always consistent among size classes and years. There were nonlinear relationships between trout counts and stream temperature in both years. Colder reaches harboured higher trout counts in the warmer summer of 2008, but this pattern was not observed in the cooler and very wet summer of 2009. Amount of pool habitat was nearly consistently important across size classes and years, and counts of the largest size class were correlated positively with maximum depth and negatively with stream gradient. Spatial mapping of trout distributions showed that reaches with high trout counts may differ among size classes, particularly between the smallest and largest size classes, suggesting that movement may allow the largest trout to exploit spatially patchy habitats in these small headwaters

Population genetics reveals bidirectional fish movement across the Continental Divide via an interbasin water transfer

Interbasin water transfers are becoming an increasingly common tool to satisfy municipal and agricultural water demand, but their impacts on movement and gene flow of aquatic organisms are poorly understood. The Grand Ditch is an interbasin water transfer that diverts water from tributaries of the upper Colorado River on the west side of the Continental Divide to the upper Cache la Poudre River on the east side of the Continental Divide. We used single nucleotide polymorphisms to characterize population genetic structure in cutthroat trout (Oncorhynchus clarkii) and determine if fish utilize the Grand Ditch as a movement corridor. Samples were collected from two sites on the west side and three sites on the east side of the Continental Divide. We identified two or three genetic clusters, and relative migration rates and spatial distributions of admixed individuals indicated that the Grand Ditch facilitated bidirectional fish movement across the Continental Divide, a major biogeographic barrier. Previous studies have demonstrated ecological impacts of interbasin water transfers, but our study is one of the first to use genetics to understand how interbasin water transfers affect connectivity between previously isolated watersheds. We also discuss implications on native trout management and balancing water demand and biodiversity conservation

Influence of rare species on electrofishing distance when estimating species richness of stream and river reaches

Abstract.-The electrofishing distance needed to estimate fish species richness at the stream or river reach scale is an important question in fisheries science. This distance is governed by the shape of the species accumulation curve, which, in turn, is influenced by a combination of factors, including the number of species, their overall abundances, habitat associations, the efficiency of the sampling method, and the occurrence of rare species. In this study we document the influence of rare species on the species accumulation curves from stream and river sites in data sets from five dispersed regions of the USA. Spatial discontinuity (i.e., a noncontinuous distribution within reaches) was observed in four of the five data sets, and the four data sets contained numerically rare species represented by one or two individuals (termed singletons and doubletons, respectively). Numerically rare species were typically proportionately rare (i.e., ,1% of the total number of individuals captured), but proportionately rare species were not always numerically rare and were dependent on the total number of fish captured. Species richness asymptotes were reached at shorter electrofishing distances when singletons and doubletons were removed. The number of singletons and doubletons in the samples remained relatively constant with increasing sampling effort (i.e., sampling distance and total abundance). Simulation modeling indicated that individual aggregation within species was not a plausible reason for spatially discontinuous species distributions. When accurately detecting the presence of species is a sampling goal, the presence and prevalence of numerically rare species may need to be considered in determining sampling protocols

Estrogenic Activities of Fatty Acids and a Sterol Isolated from Royal Jelly

We have previously reported that royal jelly (RJ) from honeybees (Apis mellifera) has weak estrogenic activity mediated by interaction with estrogen receptors that leads to changes in gene expression and cell proliferation. In this study, we isolated four compounds from RJ that exhibit estrogenic activity as evaluated by a ligand-binding assay for the estrogen receptor (ER) β. These compounds were identified as 10-hydroxy-trans-2-decenoic acid, 10-hydroxydecanoic acid, trans-2-decenoic acid and 24-methylenecholesterol. All these compounds inhibited binding of 17β-estradiol to ERβ, although more weakly than diethylstilbestrol or phytoestrogens. However, these compounds had little or no effect on the binding of 17β-estradiol to ERα. Expression assays suggested that these compounds activated ER, as evidenced by enhanced transcription of a reporter gene containing an estrogen-responsive element. Treatment of MCF-7 cells with these compounds enhanced their proliferation, but concomitant treatment with tamoxifen blocked this effect. Exposure of immature rats to these compounds by subcutaneous injection induced mild hypertrophy of the luminal epithelium of the uterus, but was not associated with an increase in uterine weight. These findings provide evidence that these compounds contribute to the estrogenic effect of RJ

Defect of Interferon γ Leads to Impaired Wound Healing through Prolonged Neutrophilic Inflammatory Response and Enhanced MMP-2 Activation.

Interferon (IFN)-γ is mainly secreted by CD4+ T helper 1 (Th1), natural killer (NK) and NKT cells after skin injury. Although IFN-γ is well known regarding its inhibitory effects on collagen synthesis by fibroblasts in vitro, information is limited regarding its role in wound healing in vivo. In the present study, we analyzed how the defect of IFN-γ affects wound healing. Full-thickness wounds were created on the backs of wild type (WT) C57BL/6 and IFN-γ-deficient (KO) mice. We analyzed the percent wound closure, wound breaking strength, accumulation of leukocytes, and expression levels of COL1A1, COL3A1, and matrix metalloproteinases (MMPs). IFN-γKO mice exhibited significant attenuation in wound closure on Day 10 and wound breaking strength on Day 14 after wound creation, characteristics that are associated with prolonged neutrophil accumulation. Expression levels of COL1A1 and COL3A1 mRNA were lower in IFN-γKO than in WT mice, whereas expression levels of MMP-2 (gelatinase) mRNA were significantly greater in IFN-γKO than in WT mice. Moreover, under neutropenic conditions created with anti-Gr-1 monoclonal antibodies, wound closure in IFN-γKO mice was recovered through low MMP-2 expression levels. These results suggest that IFN-γ may be involved in the proliferation and maturation stages of wound healing through the regulation of neutrophilic inflammatory responses

Brook Trout Populations in Headwater Stream Networks: Reproductive Biology, Riverscape Genetics and Climate Change Impact on Abundance

I used neutral genetic markers to study reproduction and landscape influence on spatial population structure, and examined climate change impact on size-specific abundance for brook trout Salvelinus fontinalis populations in two headwater stream channel networks in Connecticut. Sibship reconstruction revealed the prevalence of polygamy in males and females, a balanced sex ratio, a balanced reproductive success among individuals, and limited dispersal. The two study streams were characterized with low effective population sizes (91 and 210). Both-sex polygamy, a balanced reproductive success, and a balanced sex ratio may help maintain genetic diversity of brook trout populations with small breeder sizes persisting in headwater streams.^ Spatial population structure was observed and it was attributable to riverscape habitat variables. A weak pattern of isolation-by-distance was observed consistently despite the fine scale of investigation and spatially continuous distribution. Genetic differentiation between individuals was positively correlated with total number of confluences in both study sites, indicating the importance of dendritic habitat patterns on spatial genetic structure. In one study site, stream gradient, temperature and habitat volume were significant variables for explaining individual genetic differentiation, although their effect was confounded by correlation among riverscape variables and the presence of first-order tributaries that were identified as genetically distinguishable from each other. ^ Hierarchical regression modeling was used to understand size-specific trout abundance as a function of habitat variables. Increased stream temperature reduced abundance of nearly all size classes. Young-of-the-year trout were positively associated with the amount of riffle habitat in upstream reaches and tributaries, but the amount of pool area and maximum stream depth were important for larger trout. Under climate change scenarios, in which temperature elevation was assumed based on paired stream-air temperature records and stream flow reduction was assumed to affect pool and riffle habitats differently, brook trout of all size classes were projected to decrease in abundance overall. However, some stream segments, particularly tributaries, were projected to remain thermally suitable and harbor populations dominated by small-sized trout even under the most severe climate change scenario. As a result, the stream channel networks were projected to experience habitat loss and fragmentation as climate change progresses.

Data from: Fine-scale population structure and riverscape genetics of brook trout (Salvelinus fontinalis) distributed continuously along headwater channel networks

Linear and heterogeneous habitat makes headwater stream networks an ideal ecosystem in which to test the influence of environmental factors on spatial genetic patterns of obligatory aquatic species. We investigated fine-scale population structure and influence of stream habitat on individual-level genetic differentiation in brook trout (Salvelinus fontinalis) by genotyping eight microsatellite loci in 740 individuals in two headwater channel networks (7.7 km and 4.4 km) in Connecticut, USA. A weak but statistically significant isolation-by-distance pattern was ubiquitous in both sites. In the field, many tagged individuals were recaptured in the same 50m-reaches within a single field season (summer to fall). One study site was characterized with a hierarchical population structure, where seasonal barriers (natural falls > 1.5 m in height) greatly reduced gene flow and weaker spatial patterns emerged due to the presence of tributaries, each with a group of genetically distinguishable individuals. Genetic differentiation increased when pairs of individuals were separated by high stream gradient (steep channel slope) or warm stream temperature in this site, although the evidence of their influence was equivocal. In a second site, evidence for genetic clusters was very weak at the most, but genetic differentiation between individuals was positively correlated with number of tributary confluences. We concluded that the movement of brook trout was limited in the study headwater streams, resulting in the fine-scale population structure (genetic clusters and clines) even at distances of a few kilometers, and gene flow was mitigated by “riverscape” variables, particularly by physical barriers, waterway distance (i.e., isolation-by-distance) and the presence of tributaries

Characterization of CYCLOIDEA-like genes in controlling floral zygomorphy in the monocotyledon Alstroemeria

The CYCLOIDEA (CYC) gene controls the development of zygomorphic flowers and the determination of adaxial identity of floral organs in the model developmental system of Antirrhinum majus. However, whether CYC homologue genes also control floral zygomorphy in monocotyledon Alstroemeria plants is yet unknown. In this study, we investigated CYC-like genes in the monocotyledons Alstroemeria aurea, Alstroemeria magenta, and Alstroemeria pelegrina var. rosea, all of which have zygomorphic flowers. Since the CYC gene belongs to the T-complex protein (TCP) gene family of transcription factors, cloning of CYC-like sequences was performed using rapid amplification of cDNA ends (RACE)-polymerase chain reaction (PCR) by using degenerate primers designed for the TCP domain. We cloned 1 CYC-like sequence each from A. aurea (AaTCP1, accession number AB714967 in the GenBank/EMBL/DDBJ databases) and A. magenta (AmTCP1, AB714970), and two CYC-like sequences from A. pelegrina var. rosea (ApTCP1, AB714968; and ApTCP2, AB714969). The deduced amino acid sequences of AaTCP1, AmTCP1, ApTCP1, and ApTCP2 shared 67.7%, 67.7%, 71.0%, and 64.5% identities, respectively, with the TCP domain in CYC. Molecular phylogenetic analysis indicated that three CYC-like genes from Alstroemeria belonged to the ZinTBL1b clade in the CYC-/tb1-like subfamily. Reverse transcription (RT)-PCR and in situ hybridization analyses showed that AaTCP1 transcripts were specifically detected in flower buds and localized in the base of adaxial inner perianth of A. aurea. These results suggest that CYC-like genes are also involved in the development of floral asymmetry and the determination of adaxial identity of floral organs in the monocotyledon Alstroemeria