Relationship among cattle breed and anabolic implant protocol relative to feedlot performance: Growth, temperament, feeding behavior, carcass traits, and economic return

Recent research has suggested that different cattle breed types may respond differently to anabolic implant protocols of varying intensity. Therefore, the purpose of this research was to compare anabolic implant protocols in feedlot steers of 2 different breed types. Sixty steers were stratified by weight and breed in a 2 × 3 factorial design examining 2 different breeds: Angus (AN; n=38) or Santa Gertrudis influenced (SG; n=22), and 3 implant strategies: no implant (CON; n=20), a moderate intensity implant protocol (d0 implant: Revalor-G, d56 implant: Revalor-IS, d112 implant: Revalor-S; MI; n=20), or a high intensity implant protocol (d0 implant: Revalor-IS, d56 implant: Revalor-S, d112 implant: Revalor-200; HI; n=20). Steers were randomly placed into pens equipped with GrowSafe bunks to collect dry matter intake and feeding behavior. All animals were fed the same diet. Weight, chute score, exit velocity, serum, rectal temperature, hip height and 12th rib fat thickness were collected approximately every 28 d over a 196 d period. Serum urea nitrogen (SUN) was evaluated as well. Total average daily gain was increased (P < 0.0001) in both the HI and MI steers compared to the CON steers by 29.4% and 26%, respectively. A treatment × breed interaction was observed (P < 0.0001) for hip height, with AN-CON steers being shorter (P < 0.0007) than AN-HI, SG-CON, SG-MI, and SG-HI steers. A breed × treatment interaction was observed (P < 0.004) for chute score and rectal temperature, with SG-HI and SG-MI steers having increased chute scores (P < 0.001) when compared to AN-HI, AN-MI, AN-CON, and SG-CON throughout the course of the trial. Additionally, SG-HI and SG-MI steers had an increased rectal temperature (P < 0.004) compared to AN-HI, AN-MI, AN-CON, and SG-CON steers. A breed effect was observed (P = 0.002) for SUN with AN steers having increased (P = 0.002) SUN concentration compared to SG sired steers, in addition to a treatment effect (P < 0.0001), with CON steers having a higher (P < 0.0001) SUN concentration than MI and HI steers, regardless of breed. The MI implant protocol increased net return per head, on average, by $97.28, regardless of breed, while the HI implant protocol increased net return by only $80.84. Taken together, despite the cattle breed types responding differently to the different anabolic implant protocols at times, a moderate intensity anabolic implant protocol was optimal in this experiment for steers raised in a temperate climate.

Stream bacterial diversity peaks at intermediate freshwater salinity and varies by salt type

Anthropogenic freshwater salinization is an emerging and widespread water quality stressor that increases salt concentrations of freshwater, where specific upland land-uses produce distinct ionic profiles. In-situ studies find salinization in disturbed landscapes is correlated with declines in stream bacterial diversity, but cannot isolate the effects of salinization from multiple co-occurring stressors. By manipulating salt concentration and type in controlled microcosm studies, we identified direct and complex effects of freshwater salinization on bacterial diversity in the absence of other stressors common in field studies using chloride salts. Changes in both salt concentration and cation produced distinct bacterial communities. Bacterial richness, or the total number of amplicon sequence variants (ASVs) detected, increased at conductivities as low as 350 μS cm^-1, which is opposite the observations from field studies. Richness remained elevated at conductivities as high as 1500 μS cm^-1 in communities exposed to a mixture of Ca, Mg, and K chloride salts, but decreased in communities exposed to NaCl, revealing a classic subsidy-stress response. Exposure to different chloride salts at the same conductivity resulted in distinct bacterial community structure, further supporting that salt type modulates responses of bacterial communities to freshwater salinization. Community variability peaked at 125-350 μS cm^-1 and was more similar at lower and upper conductivities suggesting possible shifts in deterministic vs. stochastic assembly mechanisms across freshwater salinity gradients. Based on these results, we hypothesize that modest freshwater salinization (125-350 μS cm^-1) lessens hypo-osmotic stress, reducing the importance of salinity as an environmental filter at intermediate freshwater ranges but effects of higher salinities at the upper freshwater range differ based on salt type. Our results also support previous findings that ~300 μS cm^-1 is a biological effect concentration and effective salt management strategies may need to consider variable effects of different salt types associated with land-use.

Disentangling structural and functional responses of native versus alien communities by canonical ordination analyses and variation partitioning with multiple matrices

Freshwaters are under accelerated human pressure, and mollusk communities are among its most sensitive, threatened, and valuable components. To the best of our knowledge, the overall effects of damming, environment, space, time, and invasive alien mollusk species, on structural and functional responses of native mollusk communities were not yet compared. Using historical information and recent data from a river, we aimed to investigate and disentangle these effects and evaluate the differences in structural and functional responses of natives and alien invasives to the same predictors. Variation partitioning showed that alien species were as important predictors as were environmental factors and time in explaining species composition of native freshwater mollusk communities. Aliens were more independent of environmental conditions than natives and responded to different drivers, partially explaining their invasion success. The increased abundance of some alien gastropods was positively related to taxonomic diversity, while certain alien bivalves were negatively associated with the functional diversity of native communities. We introduce a cumulative variation partitioning with multiple response (native and alien) and predictor matrices, along with a diagram to show their relations, advocating for a conceptual shift in future community ecology, from “variables to matrices” and from “multivariate analyses to multi-matrix statistical modeling”.

The potential impacts of invasions on native symbionts

Symbionts, including parasites, pathogens, and mutualists, can play important roles in determining whether or not invasions by host species will be successful. Loss of enemies from the native habitat, such as parasites and pathogens, can allow for higher invader fitness in the invaded habitat. The presence of mutualists (e.g., pollinators, seed dispersers, mycorrhizae, and rhizobial bacteria) in the invaded habitat can facilitate invasion success. Although there has been a great deal of research focusing on how invading hosts may benefit from enemy losses or mutualist gains, far less attention has focused on how native symbiont populations and communities respond to invasion by non‐indigenous hosts and symbionts. In this paper, we present a conceptual framework examining how symbionts such as parasites, pathogens, commensals, and mutualists can influence invader success and whether these native symbionts will benefit or decline during invasion. The first major factor in this framework is the competence of the invading host relative to the native hosts. Low‐ or non‐competent hosts that support few if any native symbionts could cause declines in native symbiont taxa. Competent invading hosts could potentially support native parasites, pathogens, commensals, and mutualists, especially if there is a closely related or similar host in the invaded range. These symbionts could inhibit or facilitate invasion or have no discernible effect on the invading host. An understanding of how native symbionts interact with competent versus non‐competent invading hosts as well as various invading symbionts is critical to our understanding of invasion success, its consequences for invaded communities and how native symbionts in these communities will fare in the face of invasion.

Rethinking Biological Invasions as a Metacommunity Problem

Perhaps more than any other ecological discipline, invasion biology has married the practices of basic science and the application of that science. The conceptual frameworks of population regulation, metapopulations, supply-side ecology, and community assembly have all to some degree informed the regulation, management, and prevention of biological invasions. Invasion biology needs to continue to adopt emerging frameworks and paradigms to progress as both a basic and applied science. This need is urgent as the biological invasion problem continues to worsen. The development of metacommunity theory in the last two decades represents a paradigm-shifting approach to community ecology that emphasizes the multi-scale nature of community assembly and biodiversity regulation. Work on metacommunities has demonstrated that even relatively simple processes at local scales are often heavily influenced by regional-scale processes driven primarily by the dispersal of organisms. Often the influence of dispersal interacts with, or even swamps, the influence of local-scale drivers like environmental conditions and species interactions. An emphasis on dispersal and a focus on multi-scale processes enable metacommunity theory to contribute strongly to the advancement of invasion biology. Propagule pressure of invaders has been identified as one of the most important drivers facilitating invasion, so the metacommunity concept, designed to address how dispersal-driven dynamics affect community structure, can directly address many of the central questions of invasion biology. Here we revisit many of the important concepts and paradigms of biological invasions—propagule pressure, biotic resistance, enemy release, functional traits, neonative species, human-assisted transport,—and view those concepts through the lens of metacommunity theory. In doing so, we accomplish several goals. First, we show that work on metacommunities has generated multiple predictions, models, and the tools that can be directly applied to invasion scenarios. Among these predictions is that invasibility of a community should decrease with both local controls on community assembly, and the dispersal rates of native species. Second, we demonstrate that framing biological invasions in metacommunity terms actually unifies several seemingly disparate concepts central to invasion biology. Finally, we recommend several courses of action for the control and management of invasive species that emerge from applying the concepts of metacommunity theory.

Strong effects of a mutualism on freshwater community structure

Numerous mutualisms have been described from terrestrial and marine communities and many of these mutualisms have significant effects on community structure and function. In contrast, there are far fewer examples of mutualisms from freshwater habitats and there is no evidence that any mutualism has community-wide or ecosystem-level consequences. Northern hemisphere crayfish are host to a variety of ectosymbiotic worms called branchiobdellidans. The association between some of these "crayfish worms" and their hosts is a mutualism. The outcome of the association is context dependent and can be influenced by host size, symbiont number, and the environment. Here we document in two experiments that the mutualism between crayfish and these worms alters the effect of crayfish on stream community structure and sediment deposition, an important ecosystem variable. We enclosed crayfish stocked with 0 worms and intermediate (3-6) and high worm densities (12) in cages in streams in Boone, North Carolina and Clemson, South Carolina, United States. At both locations, there was a negative relationship between initial worm density and final macroinvertebrate abundance. There was a significant effect of worm treatment on macroinvertebrate community structure in both the Boone and Clemson experiments. In Boone, there were effects on both overall macroinvertebrate abundance and community composition, whereas in Clemson, changes to community structure were primarily driven by changes in total abundance. There was a negative relationship between benthic sediment volume and initial worm density in both experiments, primarily later in the experiments, though these effects were influenced by sediment deposition rates. Our results are the first to demonstrate strong effects of a mutualism on freshwater communities. Both members of this mutualism are found throughout the northern hemisphere, so similar impacts may occur in many other waterways. Given that various species in addition to crayfish function as keystone species and ecosystem engineers in freshwater systems throughout the world, mutualisms involving these strongly interacting species may be as important to the structure and functioning of freshwater systems as comparable mutualisms in marine and terrestrial systems.

Host specificity and microhabitat preference of symbiotic copepods (Cyclopoida: Clausiididae) associated with ghost shrimps (Decapoda: Callichiridae, Callianideidae)

We examined the host specificity of two ectosymbiotic Clausidium Kossman, 1874 copepods (Cyclopoida: Clausiididae) on two co‐occurrence species of host ghost shrimps. Our results revealed that both species of symbiotic copepod demonstrated extremely high host specificity. Moreover, within a single host shrimp species, each symbiont species displayed strong spatial patterns in microhabitat selection on their hosts’ bodies. Clausidium persiaensis Sepahvand & Kihara, 2017, was only found on the host Callianidea typa Milne Edwards, 1837 and almost exclusively within the host shrimp gill chamber, while C. iranensis Sepahvand, Kihara, & Boxshall, 2019 was only found on the host Neocallichirus jousseaumei (Nobili, 1904) and showed extremely strong preferences for the chelae and anterior walking legs. We also found that while the number of symbionts tends to increase with the host size, the two host species differed in the degree of symbiont infestation, with large C. typa hosting approximately 7× as many symbionts as the similarly sized N. jousseaumeia. The mechanisms resulting in the observed differences in infestation levels and microhabitat preferences of clausidium copepods among their hosts, including differences in physiology, burrowing pattern, and host grooming behavior should be further investigated.

A Multicenter Pilot Study on the Clinical Utility of Computational Modeling for Flow-Diverter Treatment Planning

BACKGROUND AND PURPOSE

Selection of the correct flow-diverter size is critical for cerebral aneurysm treatment success, but it remains challenging due to the interplay of device size, anatomy, and deployment. Current convention does not address these challenges well. The goals of this pilot study were to determine whether computational modeling improves flow-diverter sizing over current convention and to validate simulated deployments.

MATERIALS AND METHODS

Seven experienced neurosurgeons and interventional neuroradiologists used computational modeling to prospectively plan 19 clinical interventions. In each patient case, physicians simulated 2-4 flow-diverter sizes that were under consideration based on preprocedural imaging. In addition, physicians identified a preferred device size using the current convention. A questionnaire on the impact of computational modeling on the procedure was completed immediately after treatment. Rotational angiography image data were acquired after treatment and compared with flow-diverter simulations to validate the output of the software platform.

RESULTS

According to questionnaire responses, physicians found the simulations useful for treatment planning, and they increased their confidence in device selection in 94.7% of cases. After viewing the simulations results, physicians selected a device size that was different from the original conventionally planned device size in 63.2% of cases. The average absolute difference between clinical and simulated flow-diverter lengths was 2.1 mm. In 57% of cases, average simulated flow-diverter diameters were within the measurement uncertainty of clinical flow-diverter diameters.

CONCLUSIONS

Physicians found computational modeling to be an impactful and useful tool for flow-diverter treatment planning. Validation results showed good agreement between simulated and clinical flow-diverter diameters and lengths.

Compensatory dynamics stabilize aggregate community properties in response to multiple types of perturbations

Compensatory dynamics are an important suite of mechanisms that can stabilize community and ecosystem attributes in systems subject to environmental fluctuations. However, few experimental investigations of compensatory dynamics have addressed these mechanisms in systems of real-world complexity, and existing evidence relies heavily on correlative analyses, retrospective examination, and experiments in simple systems. We investigated the potential for compensatory dynamics to stabilize plankton communities in plankton mesocosm systems of real-world complexity. We employed four types of perturbations including two types of nutrient pulses, shading, and acidification. To quantify how communities responded to these perturbations, we used a measure of community-wide synchrony combined with spectral analysis that allowed us to assess timescale-specific community dynamics, for example, whether dynamics were synchronous at some timescales but compensatory at others. The 150-d experiment produced 32-point time series of all zooplankton taxa in the mesocosms. We then used those time series to evaluate total zooplankton biomass as an aggregate property and to evaluate community dynamics. For three of our four perturbation types, total zooplankton biomass was significantly less variable in systems with environmental variation than in constant environments. For the same three perturbation types, community-wide synchrony was much lower in fluctuating environments than in the constant environment, particularly at longer timescales (periods ≈ 60 d). Additionally, there were strong negative correlations between population temporal variances and the level of community-wide synchrony. Taken together, these results strongly imply that compensatory interactions between species stabilized total biomass in response to perturbations. Diversity did not differ significantly across either treatments or perturbation types, thus ruling out several classes of mechanisms driven by changes in diversity. We also used several pieces of secondary evidence to evaluate the particular mechanism behind compensatory responses since a wide variety of mechanisms are hypothesized to produce compensatory dynamics. We concluded that fluctuation dependent endogenous cycles that occur as a consequence of consumer-resource interactions in competitive communities were the most likely explanation for the compensatory dynamics observed in our experiment. As with our previous work, scale-dependent dynamics were also a key to understanding compensatory dynamics in these experimental communities.

Species Pool Functional Diversity Plays a Hidden Role in Generating β-Diversity

Functional trait diversity is used as a way to infer mechanistic processes that drive community assembly. While functional diversity within communities is often viewed as a response variable, here we present and test a framework for how functional diversity among taxa in the regional species pool drives the assembly of communities among habitats. We predicted that species pool functional diversity should work with environmental heterogeneity to drive β-diversity. We tested these predictions by modeling empirical patterns in invertebrate communities from 570 streams in 52 watersheds. Our analysis of the field data provided strong support for the inclusion of both functional diversity and environmental heterogeneity in the models, and our predictions were supported when the community was analyzed all together. However, analyses within individual functional feeding guilds revealed strong context dependency in the relative importance of functional diversity, γ-richness, and environmental heterogeneity to β-diversity. We interpret the results to mean that functional diversity can play an important role in driving β-diversity; however, within guilds the nature of interspecific interactions and species pool size complicate the relationship. Future research should test this conceptual model across different ecosystems and in experimental settings using metacommunity mesocosms to enhance our understanding of the role that functional variation plays in generating spatial biodiversity patterns.

Metacommunity theory meets restoration: isolation may mediate how ecological communities respond to stream restoration

An often-cited benefit of river restoration is an increase in biodiversity or shift in composition to more desirable taxa. Yet, hard manipulations of habitat structure often fail to elicit a significant response in terms of biodiversity patterns. In contrast to conventional wisdom, the dispersal of organisms may have as large an influence on biodiversity patterns as environmental conditions. This influence of dispersal may be particularly influential in river networks that are linear branching, or dendritic, and thus constrain most dispersal to the river corridor. As such, some locations in river networks, such as isolated headwaters, are expected to respond less to environmental factors and less by dispersal than more well-connected downstream reaches. We applied this metacommunity framework to study how restoration drives biodiversity patterns in river networks. By comparing assemblage structure in headwater vs. more well-connected mainstem sites, we learned that headwater restoration efforts supported higher biodiversity and exhibited more stable ecological communities compared with adjacent, unrestored reaches. Such differences were not evident in mainstem reaches. Consistent with theory and mounting empirical evidence, we attribute this finding to a relatively higher influence of dispersal-driven factors on assemblage structure in more well-connected, higher order reaches. An implication of this work is that, if biodiversity is to be a goal of restoration activity, such local manipulations of habitat should elicit a more profound response in small, isolated streams than in larger downstream reaches. These results offer another significant finding supporting the notion that restoration activity cannot proceed in isolation of larger-scale, catchment-level degradation.

A symbiont's dispersal strategy: condition-dependent dispersal underlies predictable variation in direct transmission among hosts

Direct horizontal transmission of pathogenic and mutualistic symbionts has profound consequences for host and symbiont fitness alike. While the importance of contact rates for transmission is widely recognized, the processes that underlie variation in transmission during contact are rarely considered. Here, we took a symbiont's perspective of transmission as a form of dispersal and adopted the concept of condition-dependent dispersal strategies from the study of free-living organisms to understand and predict variation in transmission in the cleaning symbiosis between crayfish and ectosymbiotic branchiobdellidan worms. Field study showed that symbiont reproductive success was correlated with host size and competition among worms for microhabitats. Laboratory experiments demonstrated high variability in transmission among host contacts. Moreover, symbionts were more likely to disperse when host size and competition for microhabitat created a fitness environment below a discrete minimum threshold. A predictive model based on a condition-dependent symbiont dispersal strategy correctly predicted transmission in 95% of experimental host encounters and the exact magnitude of transmission in 67%, both significantly better than predictions that assumed a fixed transmission rate. Our work provides a dispersal-based understanding of symbiont transmission and suggests adaptive symbiont dispersal strategies can explain variation in transmission dynamics and complex patterns of host infection.

The rules for symbiont community assembly change along a mutualism-parasitism continuum

Symbiont community assembly is driven by host-symbiont and symbiont-symbiont interactions. The effects that symbionts exert on their hosts are often context-dependent, and existing theoretical frameworks of symbiont community assembly do not consider the implications of variable outcomes to assembly processes. We hypothesized that symbiont-symbiont interactions become increasingly important along a parasitism/mutualism continuum because; (i) negative outcomes favour host resistance which in turn reduces symbiont colonization and subsequently reduce symbiont-symbiont interactions, whereas (ii) positive host outcomes favour tolerance and consequently higher symbiont colonization rates, leading to stronger interactions among symbionts. We found support for this hypothesis in the cleaning symbiosis between crayfish and ectosymbiotic branchiobdellidan worms. The symbiosis between crayfish and their worms can shift from parasitism/commensalism to mutualism as crayfish age. Here, field surveys identified changes in worm density, diversity and composition that were concomitant to changing symbiosis outcomes. We conducted several laboratory experiments and behavioural assays to relate patterns from the field to their likely causal processes. Young crayfish typically hosted only two relatively small worm species. Older crayfish hosted two additional larger species. In laboratory experiments, young crayfish exhibited a directed grooming response to all worm species, but were unable to remove small species. Conversely, adult crayfish did not exhibit grooming responses to any worm species. Relaxed grooming allowed the colonization of large worm species and initiated symbiont-symbiont intraguild predation that reduced the abundance and altered the behaviour of small worm species. Thus, the dominant processes of symbiont community assembly shifted from host resistance to symbiont-symbiont interactions through host ontogeny and a concomitant transition towards mutualism. This work shows that host resistance can have a prevailing influence over symbiont community assembly when symbiosis is disadvantageous to the host. However, when symbiosis is advantageous and resistance is relaxed, symbiont colonization rate and consequently abundance and diversity increases and interactions among symbionts become increasingly important to symbiont community assembly.

A Novel Eigenvector-based Method to Detect Mild Alzheimer's Disease Using Event-Related Potentials

Event-related potentials (ERPs) are a physiological measure of cognitive function that have shown diagnostic and prognostic utility in Alzheimer's disease (AD). In this study, we used a novel eigenvector-based technique to better understand brain electrophysiological differences between subjects with mild AD and healthy controls (HC). Using ERPs from 75 subjects with mild AD and 95 HC, we first calculated cognitive task eigenvectors within each subject from three conditions and then calculated second-order eigenvector components to compare the AD group to the HC group. A MANOVA of the three second-level components discriminated between AD and HC multivariately (Wilks' lambda=.4297, p<0.0001, R2 = .5703), and also on each of the three components univariately (all 3 p-values<0.0001). The eigenvector-based technique used in this study accurately discriminated between the mild AD group and HC. As such, this analysis method adds to our understanding of the differences in ERP signal between AD and HC, and could provide a sensitive biomarker for diagnosis and monitoring of AD progression.

Habitat heterogeneity and activity of an omnivorous ecosystem engineer control stream community dynamics

All communities vary through time. This variability originates from both intrinsic and extrinsic sources. Intrinsic sources are due to actions of organisms in a community, i.e., population dynamics and species interactions, while extrinsic variability is variability created by elements of habitat or environmental change. There is a growing appreciation that these two sources may interact, producing patterns of community variability that cannot be predicted or explained by focusing on a single source. We performed a field experiment that simultaneously manipulated trophic structure (intrinsic) and habitat heterogeneity (extrinsic) in order to examine the interaction between sources of variability in a South Carolina (USA) stream macroinvertebrate community. To manipulate trophic structure, we experimentally altered local abundances of crayfish which are keystone species and ecosystem engineers, while our manipulation of habitat was to alter stream substrate heterogeneity. We focused on two types of community variability as responses to our manipulations: aggregate variability (i.e., variability of summed species) and compositional variability (i.e., variability in relative abundances of species) by monitoring community composition through a 10-week experiment. We found that community dynamics shifted from patterns in variability indicative of synchrony (high aggregate variability + low compositional) to variability indicative of compensation (low aggregate variability + high compositional) along a gradient of increasing habitat heterogeneity. However, the shift in community dynamics only occurred when crayfish were present in the community. Supporting evidence from the experiment suggested that sediment engineering effects of crayfish acted as a community-wide perturbation in low-heterogeneity habitat creating synchronous dynamics. However, in high-heterogeneity enclosures, crayfish effects were moderated by refugia provided by a more complex substratum. The switch from synchronous to compensatory dynamics is significant since compensation stabilizes aggregate community properties and ecosystem functions while synchrony frequently exacerbates aggregate variability. Results from this experiment demonstrate that an interaction between intrinsic and extrinsic sources of variability can alter community dynamics and that such an alteration does not occur in the absence of an interaction.

Immuno-analysis of phospho-Akt in primary human breast cancers

The aim of this study was to investigate the expression of the activated (phosphorylated) form of Akt (Ser473) in primary breast cancer and to correlate the results with clinicopathological and prognostic variables for clinically relevant associations. Phospho-Akt expression was studied using immunoblot analysis in 49 invasive breast carcinomas (median follow-up time 55 months, range 7-74 months). We assessed the level of phospho-Akt in different types of primary breast cancers and compared the use of autoradiograph X-ray film with a PVDF-DAB-staining system. Twelve percent of the tumours had no phospho-Akt protein, 25% had low phospho-Akt expression, 51% had intermediate expression and 12% had high phospho-Akt expression. No relationship was observed between phospho-Akt and tumour grade, tumour size or nodal status. A significant relationship was demonstrated between phospho-Akt score and oestrogen receptor status (P=0.014). Univariate analysis demonstrated that intermediate levels of phospho-Akt in breast tumour tissue are associated with a lower probability of developing recurrences (P=0.035), while in multivariate analyses, none of the phospho-Akt levels appeared to be independent predictors of disease recurrence or death. In addition, it has been clearly established that a suitable composition of reagents and components such as PVDF membranes treated with DAB substrate will enable the performing of sensitive immuno-analyses.

Inhibition of compensatory renal growth by the N-terminus of a sheep-derived peptide

The N-terminal sequence of a novel sheep-derived peptide with growth inhibitory activity has been obtained. The N-terminal fragment was chemically synthesised and designated EPL001. The kidney was chosen as the first mammalian system in which to study EPL001 since kidney growth can be accurately quantified following a surgical reduction in renal mass. Cell proliferation was measured in mouse collecting duct kidney (MCDK) cells stimulated with insulin-like growth factor I (IGF-I). Compensatory renal growth (CRG) was induced in Wistar rats and either EPL001 or an EPL001 antibody delivered by continuous renal tissue infusion. Mouse monoclonal antibodies to EPL001 were generated for immunoneutralisation, rabbit polyclonal antibodies were generated for immunohistochemistry. EPL001 had no apparent effect on IGF-I stimulated cell proliferation in MCDK cells in vitro, yet provoked a dose-dependent inhibition of CRG in vivo. An EPL001 antibody potentiated CRG, in the absence of exogenous EPL001, consistent with an inhibitory role in kidney growth for an endogenous peptide containing the EPL001 sequence. Tubular staining for epitopes to the EPL001 sequence was detected in normal human kidney sections and enhanced in renal cell carcinoma. Results support the presence of growth inhibitory activity in the N-terminus of a sheep-derived peptide with evidence for both its presence and endogenous activity in the kidney. Attempts to further characterise its structure and activity are ongoing.

Atoms in a radio-frequency-dressed optical lattice

We load cold atoms into an optical lattice dramatically reshaped by radio-frequency coupling of state-dependent lattice potentials. This radio-frequency dressing changes the unit cell of the lattice at a subwavelength scale, such that its curvature and topology departs strongly from that of a simple sinusoidal lattice potential. Radio-frequency dressing has previously been performed at length scales from mm to tens of mum, but not at the single-optical-wavelength scale. At this length scale significant coupling between adiabatic potentials leads to nonadiabatic transitions, which we measure as a function of lattice depth and dressing amplitude. We also investigate the dressing by measuring changes in the momentum distribution of the dressed states.

Sublattice addressing and spin-dependent motion of atoms in a double-well lattice

We load atoms into every site of an optical lattice and selectively spin flip atoms in a sublattice consisting of every other site. These selected atoms are separated from their unselected neighbors by less than an optical wavelength. We also show spin-dependent transport, where atomic wave packets are coherently separated into adjacent sites according to their internal state. These tools should be useful for quantum information processing and quantum simulation of lattice models with neutral atoms.

Preparing and probing atomic number states with an atom interferometer

We describe the controlled loading and measurement of number-squeezed states and Poisson states of atoms in individual sites of a double well optical lattice. These states are input to an atom interferometer that is realized by symmetrically splitting individual lattice sites into double wells, allowing atoms in individual sites to evolve independently. The two paths then interfere, creating a matter-wave double-slit diffraction pattern. The time evolution of the double-slit diffraction pattern is used to measure the number statistics of the input state. The flexibility of our double well lattice provides a means to detect the presence of empty lattice sites, an important and so far unmeasured factor in determining the purity of a Mott state.

Peritoneal macrophages express the serotonin transporter

Although it is known that macrophages take up serotonin, a specific monoamine transporter has not been identified in macrophages. In this study, mRNA coding for the serotonin transporter (SERT) was detected with the reverse transcription-polymerase chain reaction (RT-PCR) in recruited mouse peritoneal macrophages. Sequencing confirmed the identity of the RT-PCR product to mouse SERT mRNA. SERT protein was detected by Western blotting. Macrophage activation with lipopolysaccharide had no effect on expression of SERT mRNA or protein. Consistent with expression of a functional SERT, specific uptake of (3)H-serotonin in macrophages was sodium dependent and inhibited by fluoxetine (IC(50) 6.9 nM) and desipramine (IC(50) 32 nM) but not by nisoxetine or reserpine.

Apoptotic mechanisms in T47D and MCF-7 human breast cancer cells

To investigate the mechanisms underlying apoptosis in breast cancer cells, staurosporine was used as an apoptotic stimulus in the human breast cancer cell lines MCF-7 and T47D. Staurosporine induced dose and time dependent increases in DNA fragmentation which was abrogated by z-VAD-fmk. MCF-7 cells did not express caspase-3, suggesting that DNA fragmentation occurred in the absence of caspase-3 and that other caspases may be involved. Staurosporine induced DEVDase activity in T47D cells suggesting the involvement of caspase-3 and/or caspase-7, yet there was no DEVDase activity in MCF-7 cells, probably ruling out the involvement caspase-7. However, staurosporine induced the cleavage of pro-caspase-6 in MCF-7 cells, but not in T47D cells. Caspase dependent PARP cleavage was detected in MCF-7 cells at 3 h, whereas only partial PARP cleavage was detected in T47D cells and then only after 24 h. Moreover, staurosporine led to cytochrome c release at 2 h in MCF-7 cells and 6 h in T47D cells. In addition, a time dependent and caspase-independent reduction of the mitochondrial transmembrane potential was observed; which appeared to occur after the release of cytochrome c. Translocation of Bax from the cytosol to mitochondria was observed in both cell types, and this preceded cytochrome c release in both T47D and MCF-7 cells. Apoptotic events in both cell types differ temporally, involving activation of different caspases and mitochondrial changes.

Cloning of the cDNA for the putative calcium-sensing receptor and its tissue distribution in sea bream (Sparus aurata)

The cDNA for the calcium-sensing receptor (CaSR) gene has been cloned from the marine teleost Sparus aurata, the sea bream. The isolated clones were 3.3 kb long with an open reading frame of 2820 bp, a 5' UTR of 240 bp, and 3' UTR of 248 bp. The gene codes for a mature peptide of 940 amino acids which has three principal domains; the extracellular region is more than half the total protein, there is a seven-transmembrane domain, and there is a short intracellular domain. There is considerable sequence identity, 91%, shared between the CaSR of sea bream and puffer fish but overall similarities with mammalian CaSR peptides vary between 44% for rat and mouse and 48% with human CaSR. Nevertheless, the 18 cysteine residues of the extracellular domain are present in all sequences so far analysed of which 9 form a cysteine-rich region in sea bream similar to mammalian CaSR. The distribution of CaSR in sea bream tissues detected by in situ hybridisation showed gene expression in epithelia associated with ion transport or ion regulation including the hind gut, chloride cells of the gills, operculum, gall bladder, pituitary adenohypophysis, and coronet cells of the saccus vasculosus; this distribution was confirmed by RT-PCR. By in situ hybridisation, CaSR gene expression was also present in olfactory nerves and leucocytes.

STR primer concordance study

Over 1500 population database samples comprising African Americans, Caucasians, Hispanics, Native Americans, Chamorros and Filipinos were typed using the PowerPlex 16 and the Profiler Plus/COfiler kits. Except for the D8S1179 locus in Chamorros and Filipinos from Guam, there were eight examples in which a typing difference due to allele dropout was observed. At the D8S1179 locus in the population samples from Guam, there were 13 examples of allele dropout observed when using the Profiler Plus kit. The data support that the primers used in the PowerPlex 16, Profiler Plus, and COfiler kits are reliable for typing reference samples that are for use in CODIS. In addition, allele frequency databases have been established for the STR loci Penta D and Penta E. Both loci are highly polymorphic.

Interleukin-1 beta induced synthesis of protein kinase C-delta and protein kinase C-epsilon in EL4 thymoma cells: possible involvement of phosphatidylinositol 3-kinase

We present evidence here that the proinflammatory cytokine, interleukin-1 beta (IL-1 beta) stimulates a significant increase in protein kinase C (PKC)-epsilon and PKC-delta protein levels and increases PKC-epsilon, but not PKC-delta, transcripts in EL4 thymoma cells. Incubation of EL4 cells with IL-1 beta induced protein synthesis of PKC-epsilon (6-fold increase) by 7 h and had a biphasic effect on PKC-delta levels with peaks at 4 h (2-fold increase) and 24 h (4-fold increase). At the level of mRNA, PKC-epsilon, but not PKC-delta levels, were induced after incubation of EL4 cells with IL-1 beta. The signalling mechanisms utilized by IL-1 beta to induce the synthesis of these PKC isoforms were investigated. Two phosphatidylinositol (PI) 3-kinase-specific inhibitors, wortmannin and LY294002, inhibited IL-1 beta-induced synthesis of PKC-epsilon. However, the PI 3-kinase inhibitors had little effect on the IL-1 beta-induced synthesis of PKC-delta in these cells. Our results indicate that IL-1 beta induced both PKC-delta and PKC-epsilon expression over different time periods. Furthermore, our evidence suggests that IL-1 beta induction of PKC-epsilon, but not PKC-delta, may occur via the PI 3-kinase pathway.

The effects of inhalation exposure to bromo-dichloromethane on specific rat CYP isoenzymes

Several cytochrome P450 (CYP) isoenzymes may be involved in the metabolism of bromo-dichloromethane (BDCM), a drinking water disinfection byproduct. After 4-h inhalation exposures of male F344 rats to BDCM between 100 and 3200 p.p.m., hepatic microsomal methoxyresorufin demethylase (MROD), ethoxyresorufin de-ethylease (EROD) and pentoxyresorufin dealkylase (PROD) activities showed modest increases at low exposure levels and larger decreases at high exposure levels, compared with controls. Western blots for CYP1A2 and CYP2B1 showed similar trends. In addition, p-nitrophenol hydroxylase (PNP) activity was measured and Western blots for CYP2E1 were performed. CYP2E1 and CYP2B1 isoenzymes are known to metabolize BDCM (Thornton-Manning, J.R., Gao, P., Lilly, P.D., Pegram, R.A., 1993. Acute bromodichloromethane toxicity in rats pretreated with cytochrome P450 inducers and inhibitors. The Toxicologist 13: 361). When compared with a multiple gavage study of BDCM in female F344 rats (Thornton-Manning, J.R., et al., 1994. Toxicology 94, 3-18), the results of the two studies for EROD, PROD, and PNP activities were qualitatively the same; PNP activity did not change, while both PROD and EROD activities decreased at high exposures. In the current work, Western blots for CYP2E1, CYP2B1 and CYP1A2 supported the results from the PNP, PROD and MROD activities, respectively. The decreases in MROD and PROD activities and in Western blots for CYP1A2 and CYP2B1 at high exposures suggest that BDCM may be a suicide substrate for these CYP isoenzymes. Other important conclusions that can be drawn from the comparison between the current and prior work are that the liver response is similar for both sexes, and it is also similar for inhalation and gavage exposures under these conditions. Finally, the decrease in EROD activity at high doses, found in both studies, may be a further reflection of CYP1A2 activity, since little or no CYP1A1 activity is normally found in uninduced rat liver and CYP1A2 is known to metabolize ethoxyresorufin, although much more slowly than CYP1A1.

Possible role for protein kinase B in the anti-apoptotic effect of prolactin in rat Nb2 lymphoma cells

Prolactin (PRL) is a mitogen for a number of cell types and its action as a survival factor has recently been demonstrated in Nb2 lymphoma cells. However, the intracellular signalling pathways by which PRL promotes the survival of Nb2 cells is unknown. In previous studies, we have shown that PRL caused the activation of phosphatidylinositol 3-kinase (PI3-kinase) and its association with tyrosine phosphorylated fyn. Protein kinase B (PKB), a serine/threonine kinase, is now known to be a downstream component of the PI3-kinase pathway. The aim of the present study was to examine the effect of PRL on the activation of PKB and to find out whether this has any role on the PRL-induced survival of Nb2 cells. Our studies have revealed the phosphorylation and activation of PKB in PRL-stimulated Nb2 cells. We have also observed, using confocal microscopy, translocation of PKB to the membrane of Nb2 cells in response to PRL. These effects were blocked by the PI3-kinase inhibitor, LY294002 (10 microgram/ml). Apoptosis was induced by the general protein kinase inhibitor, staurosporine (STS; 0.1-1 microM), the synthetic glucocorticoid, dexamethasone (Dex; 100 nM) or ionising radiation by exposing Nb2 cells to X-irradiation (IR; 10 Gy). PRL had no effect on STS-induced apoptosis. On the other hand, PRL (100 ng/ml) inhibited apoptosis induced by Dex or IR; this effect of PRL was reversed by the addition of LY294002 (10 microgram/ml). Furthermore, Western blot analysis using phosphospecific PKB antibody on lysates from PRL-treated Nb2 cells showed that phosphorylation of PKB in response to PRL was inhibited by STS (0.5 microM), but not by Dex (100 nM). These results suggest that the PI3-kinase/PKB pathway may mediate the anti-apoptotic effect of PRL in Nb2 cells.

Cloning of the cDNA for sea bream (Sparus aurata) parathyroid hormone-related protein

This paper reports cloning of the cDNA for sea bream (Sparus aurata) parathyroid hormone-related protein (PTHrP). The gene codes for a 125-amino acid mature protein with a 35-residue prepeptide. The total gene sequence is 1.8 kb with approximately 75% noncoding. The N-terminus of the protein resembles mammalian and chicken PTHrP peptides with 12 of the first 21 amino acids identical and for which there is homology with mammalian parathyroid hormone. Toward the C-terminus, the nuclear transporter region between residues 79 and 93 in sea bream is 73% homologous to tetrapod PTHrP, and the RNA binding domain, 96-117, is 50% homologous, moreover starting with the conserved lysine and terminating with the lysine/arginine sequence. Sea bream PTHrP differs significantly from mammalian and chicken PTHrP, having a novel 16-amino acid segment between residues 38 and 54 and completely lacking the terminal domain associated in mammals with inhibition of bone matrix lysis. RT-PCR and in situ hybridization of sea bream tissues show that the gene is expressed widely and the results confirm observations of a PTHrP-like factor in sea bream detected with antisera to human PTHrP.

Caspase-3-like activity is necessary but not sufficient for daunorubicin-induced apoptosis in Jurkat human lymphoblastic leukemia cells

In the present study we have shown that the cancer therapeutic drug, daunorubicin, induces apoptosis in the human lymphoblastic leukemia cell line Jurkat E6.1. This effect was both dose-and time-dependent with nuclear fragmentation detectable by 8 h. Caspases have been implicated in pro-apoptotic events. By utilizing synthetic fluorochrome-linked substrates of the caspases, we observed that a caspase-3-like enzyme had dramatically increased activity (3340 130% with respect to basal levels) in response to daunorubicin treatment. Furthermore, by using an inhibitor to caspase-3, Ac-DEVD-CHO, we have shown that activation of a caspase-3-like enzyme appears to be necessary for nuclear fragmentation and apoptotic body formation, but is not required for chromatin condensation. In contrast, a general caspase inhibitor, Z-VAD-fmk, inhibited all apoptotic parameters measured. Ceramide has been implicated in daunorubicin-induced apoptosis in human myeloid leukemia cells. However, in Jurkat cells, caspase activation does not appear to be a consequence of ceramide generation since, although ceramide levels were elevated through the action of ceramide synthase in response to daunorubicin treatment, this occurred with slower kinetics than either nuclear fragmentation or caspase activation. In contrast, caspase inhibitors abrogated ceramide elevation induced by DNR treatment, suggesting that ceramide synthase may be a downstream target for caspase action. Therefore, daunorubicin-induced apoptosis does not appear to be mediated by ceramide in the lymphoblastic leukemia cell line, Jurkat E6.1. Instead, caspase 3 activity appears to be necessary, but not sufficient for this process.

The role of caspase 3 and BclxL in the action of interleukin 7 (IL-7): a survival factor in activated human T cells

The effects of interleukin 7 (IL-7) on apoptosis in interleukin 2 (IL-2)-dependent, activated, primary, human T lymphocytes (hT cells) was examined. IL-7 (like IL-2) rescued cells from apoptosis, as measured by their cellular DNA profile and fragmentation. IL-2 also acted as a mitogen in these T cells. Both cytokines abrogated the dexamethasone-induced stimulation of Caspase 3 and prevented the cleavage of poly (ADP-ribose) polymerase (PARP), a substrate for the Caspase 3. IL-7 upregulated the expression of Bc1xL and counteracted the downregulation of this anti-apoptotic protein by the synthetic glucocorticoid, dexamethasone. Bcl-2 protein expression was uupregulated by IL-7 with or without dexamethasone, but Bc1-2 was expressed at a much lower level than BclxL in these cells. Levels of Bax did not markedly change on either cytokine stimulation or dexamethasone treatment. An unidentified 23-kDa band, which was recognized by the anti-Bc1-2 antibody, was induced by dexamthasone and suppressed by IL-7 and IL-2. This protein was subject to independent regulation as compared to the p26 Bc1-2 protein, suggesting that it may be a novel factor, possibly involved in the regulation of apoptosis. A clear role for IL-7 as a survival factor for cytokine withdrawal and glucocorticoid induced apoptosis in activated primary hT cells is implicated. In addition, regulation of BclxL and downstream inhibition of Caspase 3 activity may mediate this rescue signal.

The start-stop procedure: estimation of temporal intervals by human subjects

In four experiments investigating human timing, subjects produced estimates of sample durations by bracketing their endpoints. On each trial, subjects reproduced a sample duration by pressing a button before the estimated sample duration elapsed (start time) and releasing it after the estimated duration elapsed (stop time). From these responses, middle time (start + stop/2) and spread time (stop - start) were calculated, representing the point of subjective equality and the difference limen, respectively. In all experiments, subjects produced middle times that varied directly with sample duration. In Experiment 2, middle times lengthened when feedback was withheld. Consistent with Weber timing, spread times, as well as the standard deviation of middle times, varied directly with middle time (Experiments 1, 3, and 4). On the basis of an internal clock model of timing (Gibbon & Church, 1990), the data permitted inferences regarding memory processes and response threshold. Correlations between start and stop times and between start and spread times agreed with earlier findings in animals suggesting that the variance of temporal estimates across trials is based in part upon the selection of a single temporal memory sample from a reference memory store and upon one or two threshold samples for initiating and terminating each estimate within a trial.

Prolactin induced tyrosine phosphorylation of p59fyn may mediate phosphatidylinositol 3-kinase activation in Nb2 cells

Our previous studies indicated that PI3-kinase is involved in prolactin (PRL) signalling. We have now examined the involvement of the src tyrosine kinase, fyn, in PRL-induced the activation of PI3-kinase in the rat lymphoma cell line, Nb2. Cells were stimulated with increasing doses of PRL, lysed and immunoprecipitated with anti-fyn specific antibody. Then PI3-kinase activity was measured as the increase in the phosphorylation of phosphatidylinositol to phosphatidylinositol 3-phosphate separated by TLC. Our data indicated that, in PRL treated cells, co-precipitation of PI3-kinase with anti-fyn antiserum led to time and dose-dependent activation of PI3-kinase in vitro and that this activation was blocked by the addition of LY294002. However, LY294002 appeared to have no effect on fyn autophosphorylation. Furthermore, the physical association of PI3-kinase with fyn was confirmed by Western blot analysis employing the same specific antisera. These data provide evidence that PRL-induced activation of PI3-kinase may be mediated by the tyrosine phosphorylation of fyn in Nb2 cells.