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Adipose tissue (AT) plays a crucial role in maintaining me tabolic homeostasis by storing lipids and glucose from circulation as intracellular fat. As peripheral tissues like AT become insulin resistant, decompensation of blood glucose levels occurs causing type 2 diabetes (T2D). Currently, glycocalyx modulating as a pharmacological treatment strategy to improve glucose homeostasis in T2D patients is underexplored. Here, we show a novel role for cell surface heparan sulfate (HS) in establishing glucose uptake capacity and metabolic utilization in differentiated adipocytes. Using a combination of chemical and genetic interventions, we identified that HS modulates this metabolic phenotype by attenuating levels of Wnt signaling during adipogenesis. By engineering the glycocalyx of preadipocytes with exogenous synthetic HS mimetics, we were able to enhance glucose clearance capacity after differentiation through modulation of Wnt ligand availability. These findings establish the cellular glycocalyx as a possible new target for therapeutic intervention in T2D patients by enhancing glucose clearance capacity independent of insulin secretion.SIGNIFICANCEMetabolic disorders associated with the Western-style diet, such as type 2 diabetes, are among the main drivers of mortality in the US and globally, with more than 380 million people currently affected by this disease worldwide. However, treatment options for type 2 diabetes are currently limited to management of caloric uptake and expenditure, with none able to reverse the condition long-term. The ability to reprogram adipose tissues to improve their overall capacity to clear glucose may provide one such opportunity. Here we provide evidence that glycocalyx remodeling in pre-adipocytes with heparan sulfate mimetics will alter their differentiation program by modulating Wnt signaling to produce adipocytes with increased glucose uptake and utilization.

Sulfur (S) deficiency has been recently reported in soybean [Glycine max (L.) Merr.] producing regions across the United States. However, field studies have often failed to demonstrate a strong relationship between yield and S fertilization and generally attributing the lack of yield response to unfavorable weather and high soil S supply. In addition, only a few reports described seed composition changes due to S availability under contrasting field conditions. Therefore, our goals were (i) to implement a meta-analytic model to quantify the effect of S application at different growth stages on yield and seed concentration of protein, oil, essential non-S amino acids, and S amino acids (SAA, cysteine and methionine); ii) identify environmental factors underpinning the response of S to these plant traits. Field experiments were carried out from 2017 to 2019 growing seasons with a total of 44 unique site-years conditions across 18 locations in 8 states. Mineral S fertilizer (sulfate/ elemental S) was supplied depending on the study at sowing, vegetative and/or reproductive stages. A random-effects multilevel meta-analysis was conducted. The effect sizes compared yield and seed composition responses relative to the unfertilized control. A principal component analysis (PCA) separated distinctive environmental conditions and a sub-grouped meta-analysis with the main environmental factors was later executed to understand the response of the plant traits with those factors. Seed protein concentration increased by 0.3 % when S was applied at sowing. The concentration of SAA increased by ca. 1% regardless of the fertilization timing. Sites exposed to drought stress (18–29% reduction of potential transpiration) neither presented changes in yield nor seed composition due to S fertilization. Soils with organic matter between 25 and 32 g kg-1 (medium cluster) displayed significant responses to S application. This research brings extensive data and provides a comprehensive analysis of weather and soil attributes influencing soybean yield and seed composition responses to S availability.

Dynamic crop models that incorporate the effect of environmental variables can potentially explain yield differences associated with location, year, planting date, and cultivars with different growing cycles. Soybean ( Glycine max (L.) Mer.) cultivar coefficients for the DSSAT-CROPGRO model were calibrated from two growing seasons (2012 − 2013) comprising 58 irrigated environments (site × year × planting date combinations) for cultivars within maturity groups (MGs) 3 to 6 using end of season data (yield, seed weight, and seed oil and protein concentration) and previously calibrated phenology coefficients. Model accuracy after calibration of cultivar coefficients by MG (cultivars averaged within a MG) was similar compared to cultivar-specific coefficients. During the subsequent growing season in 2014 (33 environments), the model efficiency (ME) for predicting yield was 0.40, with a root mean square error (RMSE) of 571 kg ha − 1 . The model was less efficient predicting seed number and seed weight (ME = 0.06 and − 0.06, respectively) than yield. The model was able to simulate differences in seed oil concentration across environments and MGs (ME = 0.52), but not protein concentration (ME = − 0.25). The analysis of yield stability had similar slopes for the observed and predicted yield regressions against an observed environmental index (EI) that were only dependent on the MG. Simulated yields were significantly different from the observed when EI > 0, but yield differences in the highest yielding environments were still relatively small (245 to 608 kg ha − 1 ). The results indicate an overall robust model performance in capturing G × E responses with coefficients calibrated by MG.

The use of crop models can be limited by the need to calibrate cultivar coefficients across a sufficiently wide range of environments. The DSSAT-CROPGRO-Soybean crop simulation model considers different temperature and photoperiod sensitivities during different crop developmental stages and/or for different cultivars. The use of generic phenology coefficients specific for a range of maturity groups (MGs) could allow accurate predictions of main developmental stages in soybean without requiring calibration. Phenology data collected in 2012 and 2013 from an irrigated regional planting-date experiment with maturity group (MG) 3 to 6 cultivars and latitudes from 30.6 to 38.9°N, were used to calibrate cultivar coefficients across all the environments. A set of generic coefficients were generated based on relative maturity group (rMG) and plant growth habit. Predictions of main developmental stages in the subsequent growing season (2014) using generic coefficients were similar to predictions based on calibrated coefficients, with a RMSE across all cultivars

The largest reported soybean grain yield is approximately three-fold more than the highest reported U.S. average yield. An understanding of yield determination is needed to identify avenues for increasing yield and for defining the yield potential of soybean. To illustrate physiological traits important for yield determination, we used a framework that models yield as the product of seed number (seed m −2 ) and individual seed mass (mass seed ). Developmentally, seed m −2 is determined first and is proportional to the biomass accumulation rate (BAR, g m −2 d −1 ) and the fraction of assimilate allocated to reproductive structures. Seed m −2 is inversely proportional to the individual seed growth rate (ISGR, mg seed −1 d −1 ) where the ISGR represents the minimum amount of assimilate necessary to prevent a flower or pod from aborting. Hence, seed m −2 can be increased by optimizing conditions for crop growth (e.g., radiation interception, stress-free environment, high soil fertility levels) and having a low ISGR. Determination of mass seed occurs later during ontogeny than seed m −2 and can be expressed as the product of the ISGR and the effective seedfilling period (EFP, d). Variation among genotypes for ISGR is quite large and is generally not affected greatly by the environment. There is also genotypic variation in the EFP, but the EFP is decreased by a variety of biotic and abiotic stresses. Our analysis indicates that reaching the potential yield of soybean depends upon high BAR and extending the EFP, and a key factor affecting both of these variables is ensuring non-limiting crop nutrition, especially nitrogen. Strategies for increasing soybean maximum yield include early planting (which extends the EFP), optimizing crop nutrition, minimizing biotic and abiotic stresses, and developing breeding programs tailored for high yield environments. Characterizing physiological traits important for yield with genetic markers offers tools for combining favorable traits for high-yield environments.

Soybean (Glycine max [L.] Merr.) production tradeoffs across maturity group (MG) I through V were analyzed using data on irrigation applied, harvest index (HI), yield, and nitrogen (N) fixed in crop residue at two locations and a range of years. Water use efficiency (WUE), defined as grain yield/water (irrigation and rainfall) and nitrogen (N2) fixation prediction equations allowed analysis of tradeoffs between irrigation use and N2 fixation by MG under both irrigated and non-irrigated conditions. Analysis of partial returns by year and location revealed: (i) no consistent optimal MG choice under irrigated conditions; (ii) that irrigated soybean always outperformed non-irrigated production; and (iii) that non-irrigated MG V soybean had higher yields than earlier MG. Further, WUE, averaged across location and study years, was highest for MGs II and III with less loss in yield potential with restricted irrigation compared to MG IV and V. N2 fixation was inversely related to HI and positively correlated with Y. MG V compared to MG I, II and III thus displayed multi-fold increases in N2 fixation regardless of irrigation. Adding N fertilizer value for a subsequent crop from N2 fixation and potential implications of net GHG emissions to partial returns did not modify optimal MG choice.

Soybean ( Glycine max [L.] Merr.) N 2 fixation is a primary plant mechanism responsible for meeting plant-N demand during seed development. Nitrogen fixation is recognized as a drought-sensitive mechanism; however, N 2 fixation response to water deficit and N 2 fixation recovery at different reproductive stages are not well documented. We tested the hypothesis that water deficit during late reproductive stages would inhibit N 2 fixation and lead to the breakdown of essential leaf proteins and an inability to recover N 2 fixation. Acetylene reduction activity (ARA) and N redistribution response to a 5-d drought period at flowering (R2), early seed fill (R5), and late seed fill (R6) were evaluated in one genotype (Hendricks, maturity group 0). Control plants maintained high rates of nodule activity until late seed fill. Plants drought stressed at R2 and R5 recovered ARA after rewatering and in some cases had higher nitrogenase activity than control plants during mid-seed fill. Recovery of ARA on plants stressed at R2 and R5 was associated with higher shoot N concentration than control plants at maturity. Drought stress at R6 reduced ARA, and the inability to recover ARA after stress alleviation at R6 resulted in decreased individual seed mass, which was likely caused by an acceleration of leaf N redistribution and a shorter seed-fill period. Results emphasized the importance of soybean N 2 fixation during late seed development on seed yield and that the ability to recover N 2 fixation following drought is dependent upon crop developmental stage.

Recent changes in management of soybean production in Argentina may have large impacts on the soil water balance and on crop yield response. Changes in this system have included widespread adoption of a no-till management leaving crop residue on the soil surface, intensive cropping rotations (e.g. double cropping of wheat and soybean) so that the soil may not be fully recharged with water at the time of soybean sowing, and the occurrence of high water tables in a number of areas. The objective of this analysis was to assess the need to account for these factors in simulating soybean yields in Argentina. The influence of no-till management was simulated by simply decreasing the soil evaporation estimated for a bare soil by 70%. However, this alteration resulted in an over prediction in yield in many cases when it was assumed that the soil water content had been fully recharged at the initiation of the simulations. The difficulty with assuming a full soil water profile was confirmed when simulated yields were found to match well with observed yields when measured soil water content was used as an input to the model at the beginning of the soybean season. Finally, even with decreased soil evaporation there were still a few cases where simulated yield was less than observed yield. In these cases, a hypothetical water table, which relieved any drought stress once roots reached a depth of 1 m, resulted in yields that more closely matched observations. Overall, these results highlighted the need to estimate well both the influence of crop residue on soil evaporation and the soil water profile at sowing in simulating soybean yields in Argentina.

Drought is by far the most important environmental factor contributing to crop yield loss, especially in soyabean [Glycine max (L.) Merr.] where symbiotic fixation of atmospheric nitrogen (N2) is sensitive to even modest soil water deficits. Decline of N2 fixation with soil drying causes yield reductions due to inadequate N for protein production, which is the critical seed product. In this paper, we present a combined physiological and breeding research effort to develop soyabean lines that have diminished sensitivity of N2 fixation to drought. A preliminary physiological screen was used to identify lines that potentially expressed N2 fixation drought tolerance. One hundred progeny lines derived from a cross between Jackson, a cultivar proven to have N2 fixation tolerance to drought, and KS4895, a high-yielding line, were tested in the screen. Seventeen lines were identified for subsequent yield trials in moderate- and low-yielding rainfed environments. Two lines, found to have higher yields than commercial checks in these environments were then tested in the greenhouse for their N2 fixation activity in drying soil. Nitrogen fixation activity was found to persist at lower soil water contents than exhibited by the sensitive parent. These two soyabean lines offer a genetic resource for increased yields under rainfed conditions as a result of decreased sensitivity of N2 fixation to water deficit

Yield under drought for several crops has been established as a linear function of the cumulative water transpired during the growing season. For well-watered crops, however, there are no published data on how the duration of the cropping cycle and plant population affect the relationship between yield and transpiration. We evaluated the relationship between yield and estimated cumulative transpiration ( T ) or evapotranspiration (ET) for well-watered soybean ( Glycine max [L.] Merr.) over a wide range of maturity groups (MG, 00–VI) and population densities (10–100 plants m −2 ) for 3 years. Daily T was estimated by determining the potential ET for a given day and multiplying this by the fraction of radiation intercepted by the crop, and a crop coefficient. Soil evaporation estimates were also made using an energy-balance approach after first subtracting the amount of radiation intercepted by the canopy. Daily values of T and ET were summed from emergence to R6. For all MG, cumulative T increased linearly with increasing population density (1.30 mm plant −1 m −2 ), but predicted T at low populations ( y intercept) more than quadrupled with increasing maturity, from 121 mm (MG 00) to 584 mm (MG VI). In contrast to the linear increase of yield to cumulative T for crops under drought stress, yield response to cumulative T for fully irrigated soybean differing in maturity was described well by an exponential model, predicting that 90% of the asymptotic yield would be obtained at 444 mm of T . Accounting for differences in harvest index and vapor-pressure deficit during the season among cultivars of differing maturity did not resolve the non-linear response of yield or biomass to cumulative T . These data indicate that for water-replete conditions, decreased T associated with short-season soybean need not result in decreased yield relative to full-season cultivars.

Considerable interest in adopting earlier-maturing soybean [ Glycine max (L.) Merr. ] cultivars exists among producers in the Mid-Southern United States, as the potential for irrigation water savings and improved labor and equipment scheduling are attractive. Previous reports suggested that maturity group (MG) selection should depend primarily upon yield and not irrigation requirements, as irrigation savings generally did not offset lower yield of earlier MG. This research, however, did not account for differences in seeding rate recommendations. This report considered results from a conventional soybean (MG 00 to MG VI) population density trial (seeded at 10–100 seeds m −2 ) conducted at Fayetteville, AR for 3 years. The analysis revealed that planting soybean at the economically optimal seeding rate can lead to substantially different investment in seed (an average of $97 ha −1 for MG 00 vs. $27 ha −1 for MG VI). The results also indicated that later-maturing soybean exhibited greater flexibility in environments with plant establishment uncertainty, as the yield response to plant population density was less pronounced and investment in seed was lower compared to earlier-maturing cultivars. Later-maturing varieties did exhibit larger changes in optimal seeding rates over time than earlier-maturing varieties, however. Based on our results, a producer would be advised to examine yield potential of different MG soybean and to consider planting a range of cultivars within MG II–VI. Finally, while the numeric results of this research were location and cost specific, the analyses provided guiding principles for other regions with similar characteristics for crop establishment and replanting thresholds.

Molecular transformation is commonly offered as a hope to overcome the apparent stagnation in crop yield potential. A basic understanding of the resource limits imposed on crops and the yield hierarchy going from gene expression to harvestable yield leads to a rather negative view that transformations of a few, or even of a complex of genes will result directly in major yield increases. Forty years of biochemical and physiological research illustrate the great difficulty in translating research at the basic level into improvements in crop yield. However, there are a few cases where physiological research has led to improved crop cultivars with increased yield. These successes are instructive in highlighting key elements required to achieve success in developing crop cultivars for increased yield.

This 3-year study examines differences in simmondsin and wax ester production by 100 previously identified high-yielding jojoba clones. Over the past 3 years the USDA, ARS, National Center for Agricultural Utilization Research (NCAUR) analyzed seed samples from Purcell Jojoba International’s (PJI) large 17-year-old Variety Trial program. These 100 clones were the top producers out of 1523 clones that had been mass-selected from more than 1.5 million, open-pollinated, female plants. Broad selection criteria were applied to retain a healthy degree of the natural plants’ heterogeneity and hybrid vigor. In this study, one female clone produced 82% higher simmondsin levels than the mean of the 100 clones analyzed. Another clone produced 16% higher liquid wax ester levels than industry average. A few clones had high levels of both simmondsins and esters. In addition, the differences in fatty acid and fatty alcohol among the clones were also studied. These analyses help provide a strong foundation for major growth of the jojoba industry.

Simmondsin and several related compounds are present in jojoba meal at about 13% concentration. Industrial scale processes have been developed to extract the meal with water to yield a simmondsin concentrate that contains 43% simmondsin and analogues. This research was undertaken to develop a practical process to purify further the active constituents. Acetone, acetonitrile, chloroform, ethanol, isopropanol, methanol, and water, alone and in various combinations and at various solvent:solids ratios were tested. Extraction with absolute ethanol followed by 80:20 ethanol–water increased the concentration of simmondsins from 42 to 75% in the ethanol extract, recovered the remaining simmondsins in the second extract and left a sugar and protein residue low in residual simmondsins. Subsequent preparative chromatography gave fractions greater than 95% purity. From the preparative HPLC, 77% of the recovered fractions was of pharmaceutical grade and 20% was acceptable for further refinement or recycling into the feed solution.

A water-extract of defatted jojoba meal was filtered and concentrated from 2.6 to 23% solids on a pilot scale in a reverse osmosis concentration apparatus and then freeze-dried. The characteristics of the membrane and new concentrator were determined with both glucose and the water-extract from jojoba meal. Permeate flux was not significantly affected by the change in total flow within the controllable limits at 1, 2, 10, or 20% glucose concentration. With the total flow past the membrane maintained at 57 1/m, the permeate flux was measured at various concentrations and at different pressures across the membrane. A permeate flux rate of 2.21 × 10 −5 m/s could be maintained for glucose concentrations up to 20%. For the extract, pressure across the membrane was adjusted to maintain a permeate flux of 1.24 × 10 −5 m/s (3.8 1/min for a 5.1 m 2 surface area membrane) not exceeding the system limit of 6.9 MPa. Using this method, 193 1 of 2.6% solids jojoba extract could be concentrated to 25.3 1 of 19.7% solids in 45 min. Permeate flux decreased with time because maximum pressure could not maintain a flux rate of 1.24 × 10 −5 m/s at the higher solids concentrations. The average permeate flux over the entire experiment was 0.99 × 10 −5 m/s. Based on the pilot scale tests, 568 kg of meal were extracted and processed on industrial equipment. The process included a vacuum drum dryer coated with diatomaceous earth with spray-drying of the concentrate. A powdery solid containing 42% simmondsin and related analogues was obtained. The results of the industrial trials and recommendations for process improvements are discussed.

Saturated soil culture (SSC) is a production system developed in semiarid tropical Australia that reportedly increases soybean (Glycine max L. (Merr.)) yield above that obtained with conventional irrigation. With SSC, water is maintained in furrows between beds from early vegetative stages until maturity. The objective of this research was to evaluate SSC of soybean as an option in temperate regions for rotations in a rice-based production system. Soybean was sown in 1994 and 1995 at Keiser, Arkansas, on 15 cm high beds, spaced 1 m apart in fields precision-graded to 0.15% slope. In 1994, the cultivars were Hutcheson (MG V) and Manokin (MG IV), and in 1995, the cultivars were Asgrow 6297 (MG VI) (A6297) and Hartz 5545 (MG V) (H5545). In both years, the irrigation treatments were nonirrigated, furrow-irrigated at a 50 mm soil water deficit, and SSC. In agreement with reports from Australia, the SSC treatment resulted in leaf yellowing after treatments were established, this yellowing was associated with a lag in biomass and N accumulation in comparison with the furrow-irrigated treatment in 1994. In 1995, N accumulation rate decreased in SSC during the acclimation period, but there was no effect on biomass accumulation rate. In contrast to reports from Australia, yield was not increased by the SSC treatment. In 1994, seed yield from the SSC treatment averaged across cultivars was 40% below that from the furrow-irrigated treatment. A similar yield decrease for the SSC treatment was observed in 1995 for H5545. For A6297, however, the SSC yields and furrow-irrigated yields did not differ. In 1994 for both cultivars and in 1995 for H5545, there was a strong negative response of seed yield to depth of water in the furrow of the SSC treatment. It was concluded that there is no yield advantage from a SSC management system compared to furrow irrigation at the Arkansas site. A positive yield response of SSC may be limited to arid environments where warm temperatures and high irradiance levels contribute to overcoming the detrimental effects of SSC following treatment establishment.

Universal screening and targeted screening are the two approaches used in pediatric practice to identify children with elevated cholesterol levels. This study reports total cholesterol levels in 415 2-year-old children and the relationship of these results to risk factors. Based on these data, universal screening for total cholesterol (TC) does not appear to be necessary. Targeted screening for TC may be the more practical method for identifying children with dangerously high TC elevations.

Background TH-302 is a hypoxia targeted prodrug with a hypoxia-triggered 2-nitroimidazole component designed to release the DNA alkylator, bromo-isophosphoramide mustard (Br-IPM), when reduced in severe hypoxia. A randomized Phase 2B study (NCT01144455) was conducted to assess the benefit of G + T to standard dose G as first-line therapy of PAC. Materials and methods An open-label multi-center study of two dose levels of TH-302 (240 mg/m2 or 340 mg/m2) in combination with G versus G alone (randomized 1:1:1). G (1000 mg/m2) and T were administered IV over 30-60 minutes on Days 1, 8 and 15 of a 28-day cycle. Patients on the G could crossover after progression and be randomized to a G + T arm. The primary efficacy endpoint was a comparison of progression-free survival (PFS) between the combination arms and G alone (80% power to detect 50% improvement in PFS with one-sided alpha of 10%). Summary PFS outcome has previously been reported; more detailed PFS as well as the initial overall survival (OS) data are presented. Results 214 pts were treated; 164 (77%) Stage IV and 50 (23%) Stage IIIB. Median age 65 (range 29-86); 126 M/88 F; 40% ECOG 0/60% ECOG 1. Receiving 6 or more cycles: 32% G; 45% G + T240; 55% G + T340. Median PFS was 3.6 mo in G vs 5.5 mo in G + T240 (p = 0.031) and 6.0 mo in G + T340 (p = 0.008). Poorer prognostic factors (older age, poorer performance status, reduced albumin) were associated with larger treatment effect. Median OS was 7.0 mo in G vs 9.0 in G + T240 and 9.5 mo in G + T340. RECIST best response was 12% in G vs 17% in G + T240 and 27% in G + T340. CA19-9 decreases were significantly greater G + T340. A >50% CA19-9 decrease was 52% with G vs 50% with G + T240 and 70% with G + T340. AEs leading to discontinuation were: 16% G, 15% G + T240 and 11% G + T340. Rash (45% in G + T340) and stomatitis (36% in G + T340) were greater in combination, 4 pts Grade 3 rash. Grd 3/4 thrombocytopenia were 11% G, 39% G + T240 and 59% G + T340 and Grd 3/4 neutropenia were 28% G, 56% G + T240 and 59% G + T340. Conclusions The combination of G plus TH-302 improved the efficacy of G. A TH-302 dose of 340 mg2 was identified for future studies. Skin and mucosal toxicity and myelosuppression were the most common TH-302 related AEs with no increase in treatment discontinuation. Disclosure All authors have declared no conflicts of interest.

In our view, the idea that hexokinase might be involved in sugar sensing via a direct signaling role, rather than in its known metabolic role, remains a hypothesis and not an established fact. However, we thank Brandon Moore and Jen Sheen for their balanced response to our article1xIs hexokinase really a sugar sensor in plants?. Halford, N.G., Purcell, P.C., and Hardie, D.G. Trends Plant Sci. 1999; 4: 117–120Abstract | Full Text | Full Text PDF | PubMed | Scopus (104)See all References1. Our intention was not to criticize the previous studies, but rather to act as devil's advocate, as we felt that it was important that researchers did not dismiss other possible mechanisms of sugar sensing.To respond to the three main lines of evidence in the preceding correspondence: (1) Over-expression of yeast HXK2 in Arabidopsis resulted in elevated hexokinase activity measured in an extract2xHexokinase as a sugar sensor in higher plants. Jang, J-C. et al. Plant Cell. 1997; 9: 5–19PubMedSee all References2, but it was not shown that it increased glucose metabolism per se. (2) The recent paper by Sjef Smeekens' group3xMannose inhibits Arabidopsis germination via a hexokinase-mediated step. Pego, J.V., Weisbeek, P.J., and Smeekens, S.C.M. Plant Physiol. 1999; 119: 1017–1023Crossref | PubMedSee all References3 was not available when we wrote our article, but we agree that it appears to overcome our objection that slowly metabolizable sugars might cause ATP depletion. (3) We remain sceptical about experiments where glucose-6-phosphate (G6P) was introduced into maize protoplasts by electroporation4xSugar sensing in higher plants. Jang, J-C. and Sheen, J. Plant Cell. 1994; 6: 1665–1679PubMedSee all References4. Although it was claimed that this caused a small (∼30%) sustained increase in cellular G6P, it seems inconceivable to us that the G6P that entered would remain unmetabolized for 3 h. It also seems unwise to compare results obtained after electroporation of G6P and glucose, because the former could only enter during the brief period when the electroporation pores were open, whereas the latter would continue to enter by normal transport processes after the pores had sealed.We also take issue with two further points. A role for SnRK1 (or SNF1 for that matter) in sugar sensing does not preclude a role for hexokinase, and the demonstration that antisense expression of an SnRK1 sequence in potato tubers affected sucrose synthase gene expression5xAntisense expression of a sucrose non-fermenting-1-related protein kinase sequence in potato results in decreased expression of sucrose synthase in tubers and loss of sucrose-inducibility of sucrose synthase transcripts in leaves. Purcell, P.C., Smith, A.M., and Halford, N.G. Plant J. 1998; 14: 195–202Crossref | Scopus (139)See all References5 does not imply that sucrose synthase is the only gene controlled by SnRK1.In conclusion, we agree that plants might have multiple pathways for sensing sugars, and that these might differ from those present in yeast. However, we will retain a healthy scepticism about the signaling role of hexokinase until the putative pathway that links it to gene expression is identified. If someone can achieve this, we will be the first to congratulate them.

A simple gas proportional counter system is described that has been developed for measurements of 13 N gases in the labeled effluent from gas chromatographs and in recirculating gas atmospheres from soil cores. The gas proportional counter is designed to detect the positrons from the decay while remaining fairly insensitive to the annihilation gamma-rays. A commercial high density amplifier-comparator was used in place of traditional NIM electronics. The general properties of the system are described and compared to those employing traditional low density NIM electronics. With this system a multiple detector array can be built at low cost and without concern for cross-talk.

We have found that solder coated spring wire brushes can make a sliding superconducting contact with a rotating superconducting commutator. With a relative velocity of 0.5 cm s −1 between brushes and rotor, we observe critical currents of up to 0.1 A. Below the critical current we detect no resistance above 10 −7 Ω.