Deletion of Mgr2p Affects the Gating Behavior of the TIM23 Complex

The TIM23 complex is a hub for translocation of preproteins into or across the mitochondrial inner membrane. This dual sorting mechanism is currently being investigated, and in yeast appears to be regulated by a recently discovered subunit, the Mgr2 protein. Deletion of Mgr2p has been found to delay protein translocation into the matrix and accumulation in the inner membrane. This result and other findings suggested that Mgr2p controls the lateral release of inner membrane proteins harboring a stop-transfer signal that follows an N-terminal amino acid signal. However, the mechanism of lateral release is unknown. Here, we used patch clamp electrophysiology to investigate the role of Mgr2p on the channel activity of TIM23. Deletion of Mgr2p decreased normal channel frequency and increased occurrence of a residual TIM23 activity. The residual channel lacked gating transitions but remained sensitive to synthetic import signal peptides. Similarly, a G145L mutation in Tim23p displaced Mgr2p from the import complex leading to gating impairment. These results suggest that Mgr2p regulates the gating behavior of the TIM23 channel.Peer reviewe

Deletion of Mgr2p Affects the Gating Behavior of the TIM23 Complex

The TIM23 complex is a hub for translocation of preproteins into or across the mitochondrial inner membrane. This dual sorting mechanism is currently being investigated, and in yeast appears to be regulated by a recently discovered subunit, the Mgr2 protein. Deletion of Mgr2p has been found to delay protein translocation into the matrix and accumulation in the inner membrane. This result and other findings suggested that Mgr2p controls the lateral release of inner membrane proteins harboring a stop-transfer signal that follows an N-terminal amino acid signal. However, the mechanism of lateral release is unknown. Here, we used patch clamp electrophysiology to investigate the role of Mgr2p on the channel activity of TIM23. Deletion of Mgr2p decreased normal channel frequency and increased occurrence of a residual TIM23 activity. The residual channel lacked gating transitions but remained sensitive to synthetic import signal peptides. Similarly, a G145L mutation in Tim23p displaced Mgr2p from the import complex leading to gating impairment. These results suggest that Mgr2p regulates the gating behavior of the TIM23 channel

ESTIMATING MOIST-SOILS EEDS AVAILABLE TO WATERFOWL WITH DOUBLE SAMPLING FOR STRATIFICATION

Moist-soil managers manipulate hydrology, soils, and vegetation to provide habitat and foods for waterfowl and other wildlife in seasonally flooded herbaceous wetlands. Increasing seed availability for waterfowl is a priority, but managers also provide resources such as invertebrates, tubers, and browse (Fredrickson and Taylor 1982). An important principle in moist-soil management is maintaining a large component of early-successional plant species whose reproductive strategies include production of abundant seed (Cronk and Fennessy 2001). Low and Bellrose (1944) first referred to the annual species that colonize mudflats as moist-soil plants and documented their potential seed production. Fredrickson and Taylor (1982) developed guidelines for modern moistsoil management in the 1970s and use of moist-soil methods increased rapidly thereafter (Fredrickson 1996). In the Mississippi Alluvial Valley (MAV), state and federal wildlife agencies now manage \u3e8,000 ha in 300 impoundments for moist-soil habitat (U.S. Fish and Wildlife Service 2002). Several methods have been used to quantify seed availability in moist-soil habitats. Harvesting seeds from inflorescences has been the most common method of estimating seed production of individual plant species (Low and Bellrose 1944, Fredrickson and Taylor 1982, Haukos and Smith 1993). Other researchers have tried to simplify estimating seed production by developing species-specific predictive models relating seed yield to plant morphology (Laubhan and Fredrickson 1992; Gray et al. 1999a,b). We believe more effort is needed to develop methods to estimate seed availability for management units rather than for individual species because of the increasing number of impoundments managed and the need to understand the role of moist-soil habitat in meeting food requirements of nonbreeding waterfowl (Reinecke and Loesch 1996, Miller and Newton 1999). Double sampling for stratification (hereafter double sampling; Thompson 1992:143) potentially increases precision of estimates but does not assume that the stratum membership of plots or the sizes of strata are known. Sample units (plots) are assigned to strata during the first sampling period based on predetermined criteria, and stratum sizes are estimated as proportions of plots assigned to strata in the first sample. Successful stratification reduces sampling costs by decreasing the size of the second sample needed to achieve the desired level of precision to inform management decisions. We used double sampling to estimate seed availability in moist-soil impoundments. Our strategy involved 2 sampling steps. We selected a large first sample of plots and used qualitative criteria that we believed were correlated to seed availability to assign plots to different strata (levels of seed availability). Then we selected a second (sub)sample of the first sample, and in these plots we measured seed availability by collecting soil cores and plant inflorescences just before waterfowl arrived. We used double sampling to achieve the increased precision associated with stratified designs, and we measured seed availability by collecting soil cores and inflorescences just before waterfowl arrived to assess the abundance of resources actually available to the birds. Previous studies (Low and Bellrose 1944, Laubhan and Fredrickson 1992, Haukos and Smith 1993) have assumed that no mortality of seeds occurs between the time seeds are harvested by researchers during the growing season and the time waterfowl arrive in fall or winter. Our general objective was to determine if double sampling would provide precise, cost-effective, and unbiased estimates of seed availability in moist-soil impoundments. Specific objectives were to (1) estimate mean seed availability for 3 impoundments in each of 2 years; (2) compare the statistical and cost efficiency of double sampling to that of simple random sampling; and (3) determine if incomplete seed recovery from soil cores leads to biased estimates of seed availabilit

Microstructural Analysis of Laser Micro-Welds Between Electrode Materials for Li-Ion Battery Applications

Currently used ultrasonic welded joints for assembly and packaging of Li-Ion batteries have reliability concerns for automotive applications, as the battery is subjected to vibration and other mechanical loads. The sealing of the battery can is very critical for safety. Due to battery weld failures in recent years, the postal service has put ban on shipping Li-ion batteries via regular mail. A laser based alternative joining technology has the potential to offer robust, fast and cost-effective processing of Li-Ion batteries. Before the technology can be fully implemented, it is imperative to understand the effects of various process parameters on the robustness of the weld. In the present analysis, a preliminary study is performed to understand the effect of laser scanning speed on the micro-structural and physical characteristics of the materials in the weld area that ultimately affect the bond quality. Samples are created by welding aluminum and copper in lap shear configuration using a continuous wave fiber laser. Two sets of samples are created using a laser power of 225 W; however, the scanning speeds are 300 mm/s and 400 mm/s. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDAX) are performed in the weld area to understand the microstructural and physical characteristics of the joint that may have been affected by the processing parameters.</jats:p

Body mass dynamics in wintering mallards (Anas platyrhynchos) in the Lower Mississippi Alluvial Valley

Body mass in overwintering waterfowl is an important fitness attribute as it affects winter survival, timing of spring migration, and subsequent reproductive success. Recent research in Europe and the western United States indicates body mass of mallards (Anas platyrhynchos) has increased from the late 1960s to early 2000s. The underlying mechanism is currently unknown; however, researchers hypothesize that increases are due to a more benign winter climate, increased food availability through natural and artificial flooding, introgression of wild mallard populations by game-farm mallards, or shifting of wintering distributions northward. Further investigation of factors related to winter mallard body mass increases and whether this phenomenon is occurring in other major flyways could increase understanding of intrinsic and extrinsic variables influencing waterfowl fitness. Here, we analyzed mallard body mass in the Lower Mississippi Alluvial Valley from 1979 to 2021 to determine sources of temporal variation. We measured hunter-harvested mallards from private hunting clubs, public hunting areas, and duck-plucking businesses. Mallard body mass increased by approximately 6% among all age-sex classes from 1979 to 2021. Average mallard mass increased by about 1.5% per decade but varied substantially among years. Within years, body mass was related to rainfall and river gage height; mallards had greater mass after periods of increased rainfall or river flooding, likely due to increased food availability. Mallard body mass had a marginal negative relationship with severe cold weather (derived using a weather severity index [WSI]). While body mass increased after wet periods within years, there was no relationship of mallard body mass with wet vs dry years, low vs high flood years, or hot vs cold years. Additionally, there was no detectable change in rainfall, river discharge, or temperature from 1979 to 2021. This indicates that rainfall and river height may influence mallard body mass within years, but may not be the primary factor responsible for mass increases over time. Our research confirms changes in mallard body mass are widespread and within-season precipitation and flooding account for much of the observed annual variation. Future research investigating specific mechanisms, such as introgression of game-farm mallard DNA and climate change, may clarify their contribution to mallard body mass change over time

Intermittent Energy Restriction Attenuates the Loss of Fat Free Mass in Resistance Trained Individuals. A Randomized Controlled Trial

There is a lack of research into how lean, resistance trained (RT) individuals respond to intermittent energy restricted diets. Therefore, we investigated body composition changes in RT-individuals during continuous energy restriction or intermittent restriction. A total of 27 males and females (25 &plusmn; 6.1 years; 169 &plusmn; 9.4 cm; 80 &plusmn; 15.6 kg) were randomized to a ~25% caloric restricted diet Refeed (RF; n = 13) or Continuous group (CN; n = 14) in conjunction with 4-days/week resistance training for 7-weeks. RF implemented two consecutive days of elevated carbohydrate (CHO) intake, followed by 5-days of caloric restriction each week. CN adhered to a continuous 7-week caloric restriction. Body mass (BM), fat mass (FM), fat-free mass (FFM), dry fat-free mass (dFFM), and resting metabolic rate (RMR) were assessed pre/post-diet. Both groups significantly reduced BM (RF: baseline = 76.4 &plusmn; 15.6 kg, post-diet = 73.2 &plusmn; 13.8 kg, &Delta;3.2 kg; CN: baseline = 83.1 &plusmn; 15.4 kg, post-diet = 79.5 &plusmn; 15 kg, &Delta;3.6 kg) and FM (RF: baseline = 16.3 &plusmn; 4 kg, post-diet = 13.5 &plusmn; 3.6 kg, &Delta;2.8 kg; CN: baseline = 16.7 &plusmn; 4.5 kg, post-diet = 14.4 &plusmn; 4.9 kg, &Delta;2.3 kg) with no differences between groups. FFM (RF: baseline = 60.1 &plusmn; 13.8 kg, post-diet = 59.7 &plusmn; 13.0 kg, 0.4 kg; CN: baseline = 66.4 &plusmn; 15.2 kg, post-diet = 65.1 &plusmn; 15.2 kg, &Delta;1.3 kg p = 0.006), dFFM (RF: baseline = 18.7 &plusmn; 5.0 kg, post-diet = 18.5 &plusmn; 4.5 kg, &Delta;0.2 kg; CN: baseline =21.9 &plusmn; 5.7 kg, post-diet = 20.0 &plusmn; 5.7 kg, &Delta;1.9 kg), and RMR (RF: baseline = 1703 &plusmn; 294, post-diet = 1665 &plusmn; 270, &Delta;38 kcals; CN: baseline = 1867 &plusmn; 342, post-diet = 1789 &plusmn; 409, &Delta;78 kcals) were better maintained in the RF group. A 2-day carbohydrate refeed preserves FFM, dryFFM, and RMR during energy restriction compared to continuous energy restriction in RT-individuals

Table1_Developing a pragmatic consensus procedure supporting the ICH S1B(R1) weight of evidence carcinogenicity assessment.pdf

The ICH S1B carcinogenicity global testing guideline has been recently revised with a novel addendum that describes a comprehensive integrated Weight of Evidence (WoE) approach to determine the need for a 2-year rat carcinogenicity study. In the present work, experts from different organizations have joined efforts to standardize as much as possible a procedural framework for the integration of evidence associated with the different ICH S1B(R1) WoE criteria. The framework uses a pragmatic consensus procedure for carcinogenicity hazard assessment to facilitate transparent, consistent, and documented decision-making and it discusses best-practices both for the organization of studies and presentation of data in a format suitable for regulatory review. First, it is acknowledged that the six WoE factors described in the addendum form an integrated network of evidence within a holistic assessment framework that is used synergistically to analyze and explain safety signals. Second, the proposed standardized procedure builds upon different considerations related to the primary sources of evidence, mechanistic analysis, alternative methodologies and novel investigative approaches, metabolites, and reliability of the data and other acquired information. Each of the six WoE factors is described highlighting how they can contribute evidence for the overall WoE assessment. A suggested reporting format to summarize the cross-integration of evidence from the different WoE factors is also presented. This work also notes that even if a 2-year rat study is ultimately required, creating a WoE assessment is valuable in understanding the specific factors and levels of human carcinogenic risk better than have been identified previously with the 2-year rat bioassay alone.</p