Increasing Sucrose Concentration Research Articles

Influence of Mycorrhization on the Growth and Fructan Production in Micropropagated Agave grijalvensis (B. Ullrich) Plantlets

Agave grijalvensis (B. Ullrich) was inoculated with Glomus fasciculatum (Thaxter sensu Gerd.) Gerd. and Trappe) and fertilized with different amounts of phosphorus (P) during plant development. Mycorrhizal colonization, fructan accumulation and fructosyltransferases enzymatic activities were determined. Glomus fasciculatum increased fresh weight of A. grijalvensis, the number of leaves, root length and fructan concentrations in stems and leaves. Phosphorus increased sucrose content, but reduced glucose and fructose concentrations in both leaves and stems. Activities of 1-fructosyltransferase (1-SST) (EC 2.4.1.99) and β-fructan-1-fructosyltransferase (1-FFT) (EC 2.4.1.100) were determined and explained due to different levels of fructans detected in A. grijalvensis plantlets.

Еколого-біологічна оцінка запилення та фертильність сортів фундука в умовах Правобережного Лісостепу України

Наведено результати досліджень фертильності та життєздатності пилку сортів фундука в умовах Правобережного Лісостепу України. У досліді використано свіжозібраний пилок і через кожні дві години зафіксовано початок та динаміку його проростання. Частка життєздатного пилку визначено через 24 години за кількістю пророслих пилкових зерен у 10 полях зору мікроскопа. Пророслими вважали пилкові зерна, трубки яких мали довжину не менше, ніж діаметр пилкових зерен. Використано пилковий матеріал сортів фундука Лозівський кулеподібний, Дар Павленка, Софіївський 15, Галле, Футкурамі, Черкеський-2. Проведені дослідження свідчать про те, що розміри пилкового зерна більш вирівняні та трапляються від 25,5 до 34 мікрон, за формою фертильні пилкові зерна округлі, рідко зустрічаються трикутні. Стерильні пилкові зерна відрізняються від фертильних менш інтенсивним забарвленням та мають не чітку округлу форму. Після оцінювання якості пилку видно, що частка фертильних пилкових зерен високий і становить від 95,1 % у сорту Лозівський кулеподібний до 45,4 % у сорту Футкурамі, стерильних від 52,4 до 3,5 %, а деформованих у межах 4 %. Внаслідок проведених досліджень встановлено, що для пилку фундука властива досить висока життєздатність і фертильність. Так для максимального проростання пилку оптимальним є середовище з 15 % розчину сахарози, на якому найвища частка пророслого пилку зафіксовано в сорту Лозівський кулеподібний – 69,8 %, найнижчий показник у сорту Черкеський-2-33,1 %. Збільшення концентрації сахарози призводило до зменшення кількості пророслих зерен, пилкові трубки ставали коротшими і викривленими. Найвища частка фертильності пилку спостережено в сорту Лозівський кулеподібний – 95,1 %, найнижчий у сорту Футкурамі – 45,4 %.

Diel oscillations in cell wall components and soluble sugars as a response to short-day in sugarcane (Saccharum sp.)

BackgroundSugarcane is a tropical crop that can accumulate high concentration of sucrose in the stem as a storage carbohydrate. For that reason, sugarcane accounts for approximately 75% of all the sugar produced in the world and has become the main sugar source to produce first-generation bioethanol in Brazil. Daily rhythms cause plants to adapt and coordinate their metabolism to achieve maximum photosynthesis and carbohydrate production throughout the day. Circadian rhythms arise from the interaction of an internal oscillator and external stimuli, whereas diel rhythms occur in response to a light-dark cycle. Diel signalling contributes to synchronizing circadian rhythms to photoperiods, and levels of carbohydrates oscillate in a diel fashion. Under regular photoperiods, they are synthesized during the daytime and consumed throughout the night as an energy reserve. However, short days can induce higher rates of synthesis during daytime and lower rates of consumption in the dark. Cell wall carbohydrates are also diurnally regulated, and it has been shown that celluloses, hemicelluloses and pectin are deposited/degraded at different times of the day. To assess the diel carbohydrate profile in young sugarcane plants, we measured soluble sugars and cell wall components along a time course in plants subjected either to a regular day or short day.ResultsShort-day influenced sucrose synthesis and cell wall components. In short-day a 44% increase in sucrose concentration was detected in the dark, but was stable during the day. Cellulose, hemicellulose and pectin also fluctuate within a 24 h interval when subjected to a short day. A 38% increase in leaf sheath cellulose was observed from the middle of the day to the first hour of the night. Leaf sheath pectin and hemicellulose also increased from the day to the night, while it decreased in leaves.ConclusionsThe presented data show diurnal patterns of soluble sugar metabolism together with temporal regulation of cell wall metabolism for a short day, suggesting that diel signalling has a role in how sugarcane manages sugar accumulation and partitioning. Understanding cell wall synthesis/degradation dynamics may help to improve the yield of sugarcane.

Elicitation improves rosmarinic acid content and antioxidant activity in Thymus lotocephalus shoot cultures

Thymus lotocephalus G. Lopez & R. Morales is an aromatic species endemic to the south of Portugal with medicinal properties. The aim of this work was to evaluate the effect of elicitors, cytokinin, and different sucrose concentrations on chemical composition and antioxidant activity of extracts from in vitro regenerated shoots. Elicitors (YE: yeast extract, salicylic acid, and AgNO3) were added directly to the medium. Phytochemical analysis include evaluation of total phenolic (TPC), flavonoid (TFC), and rosmarinic acid (RAC) contents. The TPCs and TFCs were determined by Folin-Ciocalteu and aluminum chloride colorimetric assays, respectively. Rosmarinic acid (RA), the main compound found in the studied extracts, was quantified by liquid chromatography-photodiode array detector. Results showed that the cytokinin benzyladenine has an inhibitory effect on TPC, TFC and RAC, as well as on antioxidant activity. TPC was only significantly improved by the presence of YE (from 95.49 ± 3.34 to 118.34 ± 6.24 mgGAE/gextract) and TFCs were not affected by elicitation. The increase in sucrose concentration, from 2 to 4%, and the three elicitors tested, particularly YE, enhanced RACs (from 48.61 ± 0.09 in the control medium to 78.57 ± 0.99 mg/gextract in YE-elicited medium). In accordance with these results, the antioxidant activity measured by 2,2-diphenyl-1-picrylhydrazyl, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), and ferric reducing antioxidant power assays was significantly greater in extracts from elicited shoots. Overall, the results obtained suggest that shoots of T. lotocephalus are a good source of antioxidant compounds and showed that the production of RA can be promoted by altering in vitro culture conditions.

Designed Polyurethanes for Potential Biomedical and Pharmaceutical Applications: Novel Synthetic Strategy for Preparing Sucrose Containing Biocompatible and Biodegradable Polyurethane Networks

In this paper the preparation and detailed characterization of designed polyurethanes (SPURs) are reported for potential biological, biomedical and/or pharmaceutical applications. Importantly, in order to fulfill these goals all reactants and solvents used were selected according to the proposal of EUR-8 Pharmacopoeia. For the synthesis, a novel strategy was introduced and elaborated. A series of SPUR samples was prepared from poly(ε-caprolactone)-diol, 1,6-hexamethylene diisocyanate and sucrose as a chain extender/crosslinking agent to obtain sucrose containing polyurethanes. In addition, the mol ratios of the sucrose were varied within an order of magnitude. The prepolymers and the products of the syntheses were investigated by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and infrared spectroscopy (IR), respectively. It was found that the reactivity of the eight free hydroxyl groups of sucrose are different, and after curing the SPUR samples at 60 °C no free isocyanate groups can be observed. Furthermore, swelling experiments performed with various solvents of different polarities revealed that the highest degree of swelling took place in dimethyl-sulfoxide. However, low degrees of swelling were recognized in water and hexane. It is important to note that the gel contents were around 90% in all cases, which demonstrate that the crosslinking was almost complete. In addition, the kinetics of swelling were also evaluated and successfully modeled. The crosslink densities were calculated from the data of the swelling experiments by means of the Flory-Rehner equation. Unexpectedly, it was found that the crosslink density decreased with the increasing sucrose content also in line with the results obtained by relaxation modulus experiments and dynamic mechanical analysis (DMA). The Tg and Tm of SPUR samples, determined from DSC and DMA measurements, were around −57 °C and 27 °C, respectively. According to the mechanical tests the SPUR samples showed high elongation at break values, i.e., high flexibilities. Furthermore, the stress-strain curves were also modeled and discussed.

Determining the Cause of Peak Invertase Activity Delay using Isothermal Titration Calorimetry

Invertase catalyzes the hydrolysis of sucrose producing glucose and fructose. However, its mechanism of action is not well understood as other studies have shown that there is an initial delay before the enzyme reaches peak activity. This indicates that there may be another step for the active form of invertase to be activated. To better understand this mechanism, isothermal titration calorimetry (ITC) was used to measure the enzymatic activity of invertase. In this study, varying concentrations of invertase between 0.0125 to 0.125mg/mL were used to react with 1M and 2M sucrose solutions. Results show an exponential relationship between varying concentrations of invertase and the time to reach peak height. Increasing 0.0125mg/mL of invertase by tenfold, decreases the time required for the enzyme to reach peak activity by 85%. This suggests at increased invertase concentrations there is more active invertase, which may be because invertase forms a type of multimer for full activity. The effect of temperature was also explored, 1.2M sucrose was titrated into 0.016mg/mL invertase at temperatures from 25 to 55 °C. By comparing 25 and 45°C, we observed that the time required to reach peak activity decreased by 62%. However, at 55°C, the time increased by 24%. Also contributing to the delay is the viscosity of sucrose. Concentrations of sucrose ranging from 0.5 to 2M were titrated into 0.0125mg/mL of invertase. The time for the enzyme to reach peak activity increases by 23% when increasing sucrose concentration from 0.5M to 2M. However, this increase in time was also observed in the control (0.5 to 2M sucrose concentration titrated into 0.1M sodium acetate buffer). Therefore, the viscosity of sucrose does not completely account for the delay. In conclusion, the delay in peak maximal activity is in part due to increased sucrose concentration, probably due to inefficient mixing. Additionally, the delay in maximal activity is decreased in the presence of increasing invertase concentration indicating that there are inter‐invertase interactions that are required for maximal invertase activity.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Water Crystallization in Highly Concentrated Carbohydrate-Based Systems

Water crystallization was studied at a range of concentrations (20–60% solids) in sucrose and gum arabic systems. Increasing sucrose concentration reduced the nucleation temperature by 26 °C compar...

Phloem loading in cucumber: combined symplastic and apoplastic strategies.

Phloem loading, as the first step of transporting photoassimilates from mesophyll cells to sieve element-companion cell complex, creates a driving force for long-distance nutrient transport. Three loading strategies have been proposed: passive symplastic loading, apoplastic loading and symplastic transfer followed by polymer-trapping of stachyose and raffinose. Although individual species are generally referred to as using a single phloem loading mechanism, it has been suggested that some plants may use more than one, i.e. 'mixed loading'. Here, by using a combination of electron microscopy, reverse genetics and 14 C labeling, loading strategies were studied in cucumber, a polymer-trapping loading species. The results indicate that intermediary cells (ICs), which mediate polymer-trapping, and ordinary companion cells, which mediate apoplastic loading, were mainly found in the fifth and third order veins, respectively. Accordingly, a cucumber galactinol synthase gene (CsGolS1) and a sucrose transporter gene (CsSUT2) were expressed mainly in the fifth/third and the third order veins, respectively. Immunolocalization analysis indicated that CsGolS1 was localized in companion cells (CCs) while CsSUT2 was in CCs and sieve elements (SEs). Suppressing CsGolS1 significantly decreased the stachyose level and increased sucrose content, while suppressing CsSUT2 decreased the sucrose level and increased the stachyose content in leaves. After 14 CO2 labeling, [14 C]sucrose export increased and [14 C]stachyose export reduced from petioles in CsGolS1i plants, but [14 C]sucrose export decreased and [14 C]stachyose export increased into petioles in CsSUT2i plants. Similar results were also observed after pre-treating the CsGolS1i leaves with PCMBS (transporter inhibitor). These results demonstrate that cucumber phloem loading depends on both polymer-trapping and apoplastic loading strategies.

Antagonistic shifting from abscisic acid- to salicylic acid-mediated sucrose accumulation contributes to drought tolerance in Brassica napus

The phytohormone salicylic acid (SA), as an important signaling molecule involved in the regulation of plant stress responses. This study aimed to characterize the hormonal regulation of drought-responsive sugar metabolism, focusing on SA-mediated sucrose modulation with regard to the drought resistance mechanism. The responses of sucrose synthesis, starch degradation, sucrose transport, as well as stress symptom development to SA pretreatment and/or drought imposition were interpreted in relation to the altered endogenous hormonal status and their signaling genes. Drought-induced severe reduction of leaf biomass coincided with the highest endogenous level of abscisic acid (ABA) and expression of SAG12. Under drought-stressed, sugar accumulation was mainly due to the enhanced hexose level with depressed expression of hexokinase gene HXK1 and, in part, to increased sucrose content with the highest expression of ABA-dependent sucrose signaling genes SnRK2.2 and AREB2. In the presence of SA, an additional sucrose accumulation occurred with further enhancement of sucrose phosphate synthase (SPS) activity and starch degradation-related genes BAM1 and AMY3 expression, which coincided with the depression of SnRK2.2 and AREB2. Further, SA-mediated sucrose accumulation was responsible for the induction of phloem sucrose loading with enhanced expression of sucrose transporter genes SUT1 and SUT4. SA-mediated pathogenesis-related protein 2 (PR2) activation reflected a synergistic interaction between SA and sucrose signaling. These results indicate that antagonistic shifting from ABA- to SA-mediated sucrose accumulation is an important process in regulating osmotic potential and leaf senescence.

Composition of acacia honeys following processing, storage and adulteration

This study investigated the effect of different treatments (centrifugation and filtration; heating; adulteration with sugar syrups, and storage) and collection variables (year and region of the country) on the physicochemical properties of 44 Hungarian acacia honeys. The characteristics measured were diastase activity, hydroxyl-methyl-furfural (HMF), total phenolic content (TPC), electrical conductivity (EC), colour, pH, proline, moisture, sucrose, fructose and glucose contents, and concentration of eleven elements (As, B, Cd, Cr, Fe, K, Mg, Na, P, S, Zn). Centrifugation and filtration reduced the concentration of all examined parameters, except for moisture. Heating reduced diastase activity, proline and total phenolic concentrations and increased HMF concentration and colour value. Adulteration with sugar syrups had adverse effects on the diastase activity, proline, moisture and sugar concentrations, EC, colour and pH. Two-year storage reduced diastase activity, HMF, proline and TPC concentrations and increased sucrose concentrations. The collecting area influenced Na, Fe and As concentration, but the collecting year had no effect on the examined parameters. It is concluded that method and region of honey collection, duration of storage and processing all have major effects on the quality of acacia honey. Applied sugar syrup, although it affected honey quality, would be difficult to detect in the finished product.

Physical properties and optimization of bio film prepared with corn starch and Justicia adhatoda leaf extract

Justicia adhatoda leaves rich in antioxidant properties was used in increasing the edible films (EFs) functionality. In the present study, physical properties of the corn starch based EFs prepared with different concentration of sucrose, glycerol and J. adhatoda leaf extract were analyzed. The thickness of the EF ranged between 98–142 μm and increased significantly with the addition of sucrose and glycerol. Opacity (17.50–24.63%) of the film was significantly increased by the addition of J. adhatoda leaf extract. Increase in concentration of sucrose and glycerol had decreased the tensile strength (11.42 to 4.85 MPa) and increased the water vapor permeability (4.5 x 10−7 to 19 x 10−7 g.m−1pa−1). Water solubility of the films varied from 37.14 to 47.58% and it was significantly influenced by the concentration of glycerol. Film formulation at 1.14% sucrose, 21.00% glycerol and 3.00% Justicia adhatoda leaf extract was considered to be the optimized film formulation for EF preparation.

Apoplastic Invertase Activity Regulation in the Cambial Zone of Karelian Birch

We found that the regulation of apoplastic invertase (ApInv) activity in the cambial growth period in Karelian birch (Betula pendula var. carelica) is provided by the expression of encoding genes. In Karelian birches with normal wood, the content of CWIN1, CWIN1.1, and CWIN4 gene transcripts in xylem is lower than in birches with patterned wood. The regulation of ApInv activity in common silver birch (B. pendula var. pendula) is mainly provided at the posttranslational level by protein inhibitors (cell-wall inhibitor of β-fructosidase, CIF). In the trunk tissues of common silver birch, the expression level of ApInv encoding genes is similar to that of Karelian birch, but the concentration of CIF gene transcripts is increased; high expression rate of the CIF gene is caused by increased sucrose concentration in the apoplast. High activity rate of ApInv in Karelian birch provides high acceptor capacity of the cambial zone; a large amount of formed hexoses is intensely used for the formation of starch, a reserve metabolite. An increase in the wood pattern intensity correlates with the sucrose metabolization rate in the apoplastic pathway. In the trunks of birches with patterned wood, there are only local changes in the ratio of ApInv and sucrose synthase activity rates (ApInv activity higher) in the cambial growth period.

Predicting sugar content of candied watermelon rind during osmotic dehydration

Abstract Watermelon rind, comprising 35% of the fruit’s total mass, usually discarded due to its unappealing flavor and lack of sweetness. In this study, candied watermelon rind was prepared through osmotic dehydration at vacuum (VOD) and atmospheric pressure (OD). The effects of independent variables (sucrose concentration, immersion time and temperature) on the dependent variables, including solid gain (SG) and water loss (WL) of watermelon rind, were evaluated using multiple response surface methodology. The SG and WL increased with the increasing sucrose concentration, immersion time and temperature for both VOD and OD, but VOD greatly increased the mass transfer rate. The kinetic constants were obtained by fitting the data of SG and WL to the Fick’s diffusion model. The VOD had higher kinetic constants and dehydration efficiency indices than that of OD. Besides, the mass transfer model and RSM model were statistically compared by the coefficient of determination, root mean square error and absolute average deviation, based on the validation data set. The RSM and mass transfer models provide information about the osmotic dehydration for predicting the sugar content of candied product, and helping the designers and researchers find the best design parameters and the most effective process conditions.

Independent effects of dietary fat and sucrose content on chondrocyte metabolism and osteoarthritis pathology in mice.

ABSTRACTObesity is one of the most significant risk factors for knee osteoarthritis. However, therapeutic strategies to prevent or treat obesity-associated osteoarthritis are limited because of uncertainty about the etiology of disease, particularly with regard to metabolic factors. High-fat-diet-induced obese mice have become a widely used model for testing hypotheses about how obesity increases the risk of osteoarthritis, but progress has been limited by variation in disease severity, with some reports concluding that dietary treatment alone is insufficient to induce osteoarthritis in mice. We hypothesized that increased sucrose content of typical low-fat control diets contributes to osteoarthritis pathology and thus alters outcomes when evaluating the effects of a high-fat diet. We tested this hypothesis in male C57BL/6J mice by comparing the effects of purified diets that independently varied sucrose or fat content from 6 to 26 weeks of age. Outcomes included osteoarthritis pathology, serum metabolites, and cartilage gene and protein changes associated with cellular metabolism and stress-response pathways. We found that the relative content of sucrose versus cornstarch in low-fat iso-caloric purified diets caused substantial differences in serum metabolites, joint pathology, and cartilage metabolic and stress-response pathways, despite no differences in body mass or body fat. We also found that higher dietary fat increased fatty acid metabolic enzymes in cartilage. The findings indicate that the choice of control diets should be carefully considered in mouse osteoarthritis studies. Our study also indicates that altered cartilage metabolism might be a contributing factor to how diet and obesity increase the risk of osteoarthritis.

Visualization of soluble carbohydrate distribution in apple fruit flesh utilizing MALDI–TOF MS imaging

To confirm availability of Matrix-assisted laser desorption/ionization time-of-flight (MALDI–TOF) mass spectrometry imaging (MSI) for visualizing distribution of soluble carbohydrates in apple (Malus domestica) fruits a horizontal fruit flesh specimen was cut from a matured ‘Fuji’ fruit, mounted on a glass slide, lyophilized and then ion intensities of individual soluble carbohydrates were probed around the specimen using a MALDI–TOF MSI apparatus automatically. Contents of soluble carbohydrates in adjacent tissue of the same fruit were also determined using HPLC to compare the distribution of individual carbohydrate based on the ion intensities from MALDI–TOF MSI with those from HPLC. Positive correlation (P < 0.001, R2 > 0.95) was confirmed between the concentration of each standard carbohydrate and the relative ion intensity of MALDI–TOF mass spectrometry (MS), and thus it seems possible to use the ion intensity of MALDI–TOF MS for determining the relative concentration of carbohydrates in a sample. Singly charged ions attached with a potassium ion only were detected from the apple fruit specimen when DHB was used as a matrix for MALDI–TOF MSI. Graded increase of sucrose content from center to cortex side of the fruit flesh was confirmed by both MALDI–TOF MSI and HPLC. When pseudo color images on the distribution of individual carbohydrates based on the results from MALDI–TOF MSI were compared with the content of carbohydrates in the adjacent 16 tissue blocks quantified using HPLC, strong (P < 0.001, R2 = 0.6222) and weak (P < 0.10, R2 = 0.2123) correlation was confirmed between the brightness and the content of sucrose and sorbitol, respectively. These facts indicate that distribution of sucrose and sorbitol in apple fruit tissue can be visualized using MALDI–TOF MSI. Thus, MALDI–TOF MSI will be useful for examining carbohydrate metabolism during the maturing of apple fruit.

In vitro Growth of Genovese Basil in Response to Different Concentrations of Salts and Interaction of Sucrose and Activated Carbon

Genovese basil has great economic potential; however, there is no established micropropagation protocol for this species. Therefore, this study aimed at assessing the in vitro growth of Genovese basil in response to different concentrations of salts in the Murashige and Skoog medium (MS) and interaction of sucrose and activated carbon. Two assays were conducted independently in an in vitro environment using the MS medium, regulators, agar, and five salt concentrations (0, 25, 50, 70 and 100%). In the second assay, two concentrations of sucrose (30 and 60 g L-1) and three concentrations of activated carbon (0, 3.0, and 4.5 g L-1) were tested.In addition, copper and zinc were quantified in the roots. The results showed that shoots were favored when the medium was at its full strength (100% salts), with seedlings forming more leaves.This result may be associated with a higher demand for nitrogen and because of the ionic balance between NH4+ and NO3-. High concentrations of salts affected the roots, but a reduction to 70% salt favored root development. Doubling the usual dose of sucrose (60 g L-1) damaged the growth of the seedlings. Damage caused by osmotic and oxidative potentials, and by toxic compounds may be related to the observed results. The amount of copper and zinc in the root increased with increased concentrations of activated carbon in the medium. The presence of activated carbon reduced callus formation but did not mitigate the effects of increased sucrose concentration.

Apple Intrinsic Factors Modulating the Global Regulator, LaeA, the Patulin Gene Cluster and Patulin Accumulation During Fruit Colonization by Penicillium expansum.

The mycotoxin patulin is produced in colonized tissue by Penicillium expansum during storage of apples and is significantly affected by environmental factors that contribute to its accumulation. Few reports have, however, examined the effect of natural intrinsic factors associated with the fruit on the production of patulin. Here, we find that with advancing maturity, Golden Delicious apples show increased concentrations of total soluble solids (TSS) from 14 to 17% associated with the increased expression of the global transcription factor involved in regulation of secondary metabolite biosynthesis in filamentous fungi, laeA expression and patulin accumulation. However, the apple cultivar Granny Smith, with similar TSS values but differing in pH levels and malic acid concentrations, showed reduced expression levels of laeA and the patulin biosynthesis gene cluster (pat genes) and patulin accumulation, suggesting a complexity of host factors contribution to patulin accumulation during P. expansum colonization. To start elucidating these apple intrinsic factors, we examined their in vitro impact on laeA and pat gene expression concomitant with patulin synthesis. Increasing sucrose concentrations from 15 to 175 mM repressed laeA and pat gene expression and patulin production. However, this affect was modified and often reversed and sometimes accentuated by changes in pH, or the addition of malic acid or the major apple phenolic compounds, chlorogenic acid and epicatechin. While the increase in malic acid from 0 to 1% increased laeA and pat gene expression, the decrease in pH from 3.5 to 2.5 reduced their expression. Also the increased laeA and pat genes expressions at increasing epicatechin concentrations from 0 to 1 mM, was reversed by increasing sucrose concentrations, all together suggesting the complexity of the interactions in vivo.

The effects of sucrose on urine collection in metabolic cages.

Representative urine collection that respects the standards of animal welfare is still an issue in experimental nephrology. The commonly used metabolic cages induce stress in rodents. In mice, the volume of collected urine is sometimes insufficient for further analysis. The aim of this experiment was to analyse the effects of time of day, temperature and 2%, 5% or 10% sucrose solutions on diuresis, weight change and liquid intake of adult mice placed in metabolic cages for urine collection. Mice were placed in metabolic cages for 12 h during the day or night at standard ambient (22℃) and thermoneutral (28℃) temperatures. To determine the effect of acclimatisation, mice were placed in metabolic cages for five consecutive days. Diuresis increased with concentrations of sucrose. Body weight reduction was most rapid in the group given tap water and decreased with increasing sucrose concentrations. A drastic drop in body weight was observed in mice placed in metabolic cages for four consecutive days with access to tap water and food, indicating that time spent in metabolic cages should be kept to a minimum, as prolonged confinement in metabolic cages can be harmful to mice. The administration of concentrated sucrose solutions can potentially aid in mouse urine collection by reducing the time spent in metabolic cages. Sucrose supplementation increased the albumin/creatinine ratio. However, without showing estimates of glomerular filtration rate, renal haemodynamics, plasma electrolytes and urinary electrolyte excretions, the results of this study do not provide any conclusion about the effect of sucrose on renal function.

Sucrose-Caused Changes in the Frequency and Localization of Anticlinal Divisions in the Cambial Zone of Silver Birch

This study continues our previous experiments intended to elucidate the role of sucrose in a figured wood formation in silver birch (Betula pendula Roth var. carelica). The purpose of the study was the investigation of the role of sucrose in the regulation of cell division in the cambial zone. Using an earlier-developed technique, sucrose solutions of different concentrations have been delivered into trunk tissues of silver birch. A microscopic analysis of samples collected 28 days after the beginning of the experiment has shown that an increased sucrose concentration in an exogenous solution causes an increase in the frequency of anticlinal cell divisions in the cambial zone. In the case of high sucrose concentrations (10 or 20%), the zone of anticlinal divisions is significantly wider than in variants with low sucrose concentrations, since anticlinal divisions are observed on both phloem and xylem sides and at a larger distance from rays. A comparison of the obtained results with the previous experiments shows that the increased frequency of anticlinal divisions in cambial cells observed in the case of application of 10 or 20% sucrose solutions coincides with an increased parenchymatization of tissues. A revealed localization of anticlinal divisions within the cambial zone indicates that, in the case of the exogenous sucrose uptake, the morphogenesis of conductive tissues in silver birch (Betula pendula Roth var. pendula) occurs in the same way as in Karelian birch (Betula pendula Roth var. carelica). Data presented in this paper agree with the earlier hypothesis that the formation of figured wood similar to that of Karelian birch occurs due to increased sucrose content in trunk tissues.

Direct somatic embryogenesis of potato [Solanum tuberosum (L.)] cultivar ‘Kufri Chipsona 2’

Direct somatic embryo induction was achieved from leaf and internodal explants of Solanum tuberosum (L.) cultivar ‘Kufri Chipsona 2’ on Murashige and Skoog (Physiol Plant 15:473–497, 1962) medium containing 10.0 µM silver nitrate (MS1 medium) supplemented with 2,4-dichlorophenoxyacetic acid (2,4-D; 2.5 µM) and 6-benzyladenine (BA; 1.0 µΜ). It was observed that in absence of AgNO3, friable callus was induced from cut ends of the explants, which does not develop into any kind of organised structure; thus highlighting the requirement of AgNO3 for somatic embryogenesis in potato. Furthermore, the effect of medium strength, sucrose concentration and heat shock treatment on somatic embryogenic potential of explants was also investigated. When the strength of basal medium was reduced to half, the frequency of internodal segments differentiating somatic embryos was almost double in comparison to full strength MS medium. Sucrose concentration and heat shock treatment were found to have interactive effect on somatic embryo induction. Explants subcultured on medium containing 174 mM sucrose and subjected to heat shock (1 h; 50 °C) showed maximum somatic embryo differentiation. Although, the percent explants differentiating somatic embryos decreased sharply with increase in sucrose concentration (> 174 mM), yet the number of somatic embryos differentiated per explant were found to increase with further increase in sucrose concentration. Histological observations revealed that somatic embryos directly developed from epidermis of leaf explant and cut ends of internodal segments progressed from globular to cotyledonary stage after passing through intermediate embryogenic stages (heart shaped and torpedo shaped). Conversion of somatic embryos into plantlets (92%) was achieved on MS1 medium supplemented with BA (10.0 µM) and gibberellic acid (15.0 µM) and all regenerated plants were found to be phenotypically alike.