100mM Sucrose Research Articles

Diluent Containing Dimethylformamide Added With Sucrose Improves In Vitro Quality After Freezing/Thawing Stallion Sperm

The aim of this study was to investigate the effects of sucrose on post-thawed equine semen quality. Semen samples (n = 24) were collected from six stallions. They were diluted (200 × 106 sperm/mL) in a freezing medium based on skimmed milk, egg yolk, dimethylformamide, and supplemented with sucrose at concentrations of 0 (Control), 25, 50, and 100 mM and in a commercial extender (BotuCrio). Subsequently, they were filled in straws (0.5 mL) and subjected to freezing and storage (−196°C). Immediately after thawing (37°C, 30 seconds), semen samples were evaluated for kinetics (CASA), plasma and acrosomal membrane integrity, and mitochondrial membrane potential (flow cytometry). The addition of 50 and 100mM sucrose to the freezing extender increased (P < .05) the parameters of TM, PM, VCL, VSL, and VAP, compared to the control group. The WOB parameter of the group supplemented with 100 mM sucrose was higher (P < .05) than the control group. Higher values ​​(P < .05) of ALH and BCF were observed in groups treated with sucrose (25, 50, and 100 mM), compared to BotuCrio. The semen frozen in the presence of 100 mM sucrose presented higher percentages (P < .05) of sperm with intact plasma and acrosomal membranes, and high mitochondrial membrane potential in relation to the other groups. It is concluded that the addition of sucrose to equine semen freezing extender increase motility (50 and 100 mM), plasma and acrosomal membrane integrity preserve, and high sperm mitochondrial membrane potential (100 mM) after thawing.

Exogenous Sucrose Protects Potato Seedlings Against Heat Stress by Enhancing the Antioxidant Defense System

To analyze the ability of exogenous sucrose application to moderate adverse effect of high-temperature stress on potato seedlings. Potato (Solanum tuberosum L.) seedlings were pretreated with 100-mM sucrose solution for 24 h and then exposed to a heat stress treatment at 42 °C. Our results showed that exogenous sucrose enhanced the thermotolerance of potato seedlings and alleviated morphological injuries caused by heat stress. Sucrose pretreatment was found to efficiently inhibit heat stress-induced increases in electrolyte leakage in potato leaves and to reduce the accumulation of reactive oxygen species (ROS) such as superoxide radicals (O2•-) and hydrogen peroxide (H2O2) under heat stress. Sucrose treatment alone was found to significantly enhance peroxidase activity (POD), ascorbate peroxidase (APX), and endogenous sucrose content. Additionally, sucrose pretreatment was also found to help maintain higher activities of antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), APX, and POD, and to increase the accumulation of endogenous sucrose and proline in leaves when potato seedlings were exposed to heat stress for 6 and 8 h. Our results show that sucrose can alleviate the detrimental effects of heat stress on potato seedlings by enhancing the antioxidant enzyme system and increasing sucrose and proline accumulation. Therefore, exogenous sucrose treatment may be a useful experimental tool to enable potato plants to tolerate heat that might otherwise cause plants to accumulate lethal levels of ROS.

Differential carbohydrate dynamics in Arabidopsis wild-type and ntrc mutant after trehalose feeding

The trehalose sugar plays pivotal roles in plants. In Arabidopsis, trehalose supplied to the medium leads to starch accumulation through redox activation of the ADP-glucose pyrophosphorylase (AGPase) by the NADPH-dependent thioredoxin reductase C (NTRC). To gain further insight on the regulation of carbohydrate metabolism by trehalose and NTRC, Arabidopsis wild-type (wt) and ntrc plants were raised in the MS medium supplemented with or without 100-mM sucrose or trehalose and alterations in sugar and starch contents as well as the activities and expressions of some carbohydrate metabolizing enzymes were investigated. The ntrc plants displayed lower growth rate compared to wt by sugar feeding. Under trehalose treatment, the total soluble, reducing and non-reducing sugars of wt and ntrc plants decreased between end of the day and end of the night, but starch in the ntrc plants remained unaltered during the aforementioned period. The obtained data showed that trehalase activity and gene expression display diurnal rhythms. Meanwhile, under darkness, trehalase gene expression required functional NTRC. Trehalose feeding induced NTRC expression during the day, but suppressed it during the night. Moreover, AGPase expression found to be jointly regulated by carbon nutrition and the light–dark period in both wt and mutant plants. The current data also revealed that AMY3 (α-amylase 3) gene expression depends on the presence of functional NTRC in plants. It seems that cross-talk between trehalose and NTRC regulates diurnal carbohydrate metabolism in plants.

Effectofsucrose concentrations on Stevia rebaudiana Bertoni tissue culture and gene expression.

Stevia rebaudiana (Bert.) Bertoni is known as sweet plant which it contains a high level of steviol glycosides in the leaves. This plant has been used from centuries ago as a sweetener for tea. One of the most important steviol glycosides is stevioside that is attractive for diabetic persons. Tissue culture is the only rapid process for the mass propagation of stevia. One of the most important factors in the medium is sucrose that is a necessary for plant growth. In the present study, we use nodal segments of the stem as explants in mediums with different sucrose concentration (50 mM, 100mM and 150mM). Several morphological traits were measured in a 28 day period. Results analysis showed a significant variation between treatments. The highest growth rate, rooting and leaf production was obtained in medium with 100mM sucrose. The correlation between measured traits was significant at the 0.01 level. To investigation of UGT74G1, UGT76G1, UGT85C2 and KS genes expression that are involved in the synthesis of SGs, RT- PCR was done with the housekeeping gene of as internal control. There were significant differences between all media. The results showed thatsucrose 100 mM containing media was more desirable than others for expression of UGT76G1 and UGT85C2 genes. Whereas, the best medium for expression of UGT74G1 was sucrose 150 mM and sucrose 50 mM for KS gene. Totally, it seems that sucrose at a concentration of 100 mMprovides the best condition for stevia growth and steviol glycosides production.

A kinetic model of one-pot rapid biotransformation of cellobiose from sucrose catalyzed by three thermophilic enzymes

Cellobiose is a zero-calorie functional sweetener and a potential healthy food/feed additive. Current production methods of cellobiose from high-purity cellulose always suffer from low product yields and high separation costs. Here one-pot biotransformation composed of three thermophilic enzymes sucrose phosphorylase (SP) from Thermoanaerobacterium thermosaccharolyticum, glucose isomerase (GI) from Streptomyces murinus, and cellobiose phosphorylase (CBP) from Clostridium thermocellum was designed to convert sucrose to cellobiose. To reveal the underlying relationship within the three enzymes and optimize reaction conditions, a kinetic model was developed. Model simulation predicted the optimal SP:GI:CBP enzyme loading ratio in terms of enzyme unit was 0.5:1.0:1.5. The enzyme cocktail with the optimal ratio converted 100mM sucrose to 62.3mM cellobiose within 10h. Model simulation also found out that the optimal phosphate concentration was approximately 10.3mM for 100mM sucrose, which was validated by experimental data. This study could assist the sugar industry to diversify the production of new value-added products from sucrose.

An automated learning apparatus for classical conditioning of Lymnaea stagnalis

BackgroundThe pond snail Lymnaea stagnalis is capable of taste avoidance classical conditioning (TAC) with sucrose as the conditional stimulus (CS) and mechanical prodding as the unconditional stimulus (US). After successful training, feeding behavior is significantly suppressed in response to CS presentation. New methodAn automated apparatus is described for the training of multiple snails up to 10 snails at the same time. The new apparatus employs an electrical shock obtained from a 9-V dry cell to deliver a consistent and effective current amplitude of 0.4μA (i.e., the US). ResultsUsing this apparatus, 10 snails can be conditioned simultaneously. We found that the optimal parameters to result in both short (STM) and long-term memory (LTM) were 15 paired presentations of the CS and US with a 5-min inter-trial interval (ITI) and 0.2-s current duration. However, both STM and LTM were observed with other ITIs tested. Successful TAC with only a single pairing of the CS–US occurred with a CS of 100mM sucrose solution for 60s followed by a US of 9V with 0.4μA for 5s. Comparison with existing methodThe use of automated training apparatus for TAC will enable us to better examine the relationship between strength of CS and US.

Successful ultrarapid cryopreservation of wild Iberian ibex (Capra pyrenaica) spermatozoa

A method for cryopreserving wild ibex sperm at high cooling rates was developed. To design a freezing solution based on Tris, citric acid, and glucose (TCG), two preliminary experiments were performed using glycerol (GLY) and dimethyl sulfoxide (DMSO) at different concentrations (5%, 10%, 20%). The 10% GLY + 10% DMSO combination reduced (P < 0.05) frozen-thawed sperm motility, which reached a minimum when 20% GLY + 20% DMSO was used. In the second experiment, sperm tolerance to three sucrose concentrations was evaluated (100-mM sucrose, 300-mM sucrose, 500-mM sucrose). Frozen-thawed sperm motility and sperm viability decreased (P < 0.05) at concentrations above 300 mM. The ultrarapid cooling procedure finally used involved a TCG egg yolk (ey)–based extender with 100-mM sucrose, either alone or with 5% GLY with or without BSA. Two warming procedures (37 °C vs. 60 °C) were also evaluated. The TCG ey with 100-mM sucrose but without GLY/BSA returned the best sperm quality variables. Slow warming at 37 °C strongly affected (P < 0.05) sperm motility and viability in all groups. Sperm selection by density gradient centrifugation produced no motile sperm when slow warming was performed. In contrast, when fast warming was used, sperm selection increased (P < 0.05) percentage of motility, viability, and the percentage of sperms with intact acrosomes. Heterologous in vivo fertilization involving domestic goats was performed to evaluate the in vivo fertilization capacity of the ultrarapidly cooled cryopreserved sperm (in TCG-ey + 100 mM sucrose), with warming undertaken at 60 °C. Inseminations of domestic goats resulted in three pregnancies (3 of 16, 18.7% fertility). In conclusion, ibex spermatozoa are strongly sensitive to high concentrations of permeable cryoprotectants and sucrose. However, the combination of ultrarapid cooling, using TCG-ey + 100-mM sucrose, and fast warming at 60 °C, followed by sperm selection by density gradient centrifugation to collect the motile sperm, has a positive effect on sperm viability.

Sperm morphology, ultrastructure, and motility in pikeperch Sander lucioperca (Percidae, Teleostei) associated with various activation media

Spermatozoa morphology, ultrastructure, and spermatozoa motility traits were studied in pikeperch (Sander lucioperca) after activation in various media (AM 1 &amp;ndash; 45mM NaCl, 5mM KCl, 20mM Tris, pH 8.5; AM 2 &amp;ndash; 100mM sucrose, 20mM Tris, pH 8.5; AM 3 &amp;ndash; 100mM sucrose, 1mM CaCl&lt;sub&gt;2&lt;/sub&gt;, 20mM Tris, pH 8.5) during a 48-hour storage period. The spermatozoon was acrosomeless and differentiated into a spherical nucleus (head), midpiece, and flagellum. The nucleus length and width measured 1.83 &amp;plusmn; 0.03 and 1.63 &amp;plusmn; 0.02&amp;nbsp;mm, respectively. The midpiece was located laterally to the nucleus and possessed proximal and distal centrioles and 2&amp;ndash;4 mitochondria. Flagellar length was 33.2 &amp;plusmn; 0.90 &amp;micro;m, and a pair of lateral fin-like structures projections was observed. The axoneme consisted of nine peripheral doublet microtubules and a single central pair. After a 24 h storage in all activation media at all sampling times post-activation (15, 45, 90, and 120 s), spermatozoa motility was significantly decreased. Spermatozoa were motile after the 48-hour storage at all sampling times post-activation only in AM 3. After the 48-hour storage, no motile spermatozoa were observed in AM 2 and AM 1 at 90 and 120 s post-activation, respectively. Differences in spermatozoa velocity varied with activation medium during storage. After the 48-hour storage in AM 1 and AM 2, decrease of spermatozoa velocity at 15 s post-activation was observed, while in AM 3, velocity was decreased only after the 48-hour storage. Pikeperch spermatozoa morphology and ultrastructure was found similar to that of most freshwater teleosts, with differences in the arrangement of midpiece, number of mitochondria, and position of centrioles. Viable pikeperch sperm was observed after the 48-hour storage. Motility of spermatozoa was improved by addition of Ca&lt;sup&gt;2+&lt;/sup&gt; to the activation medium, where higher spermatozoa velocity was observed.

The spike generator in the labellar taste receptors of the blowfly is differently affected by 4-aminopyridine and 5-hydroxytryptamine

In taste chemoreception of invertebrates the interaction of taste stimuli with specific membrane receptors and/or ion channels located in the apical membrane of taste receptor cells results in the generation of a receptor potential which, in turn, activates the ‘encoder’ region to produce action potentials which propagate to the CNS.This study investigates, in the labellar chemosensilla of the blowfly, Protophormia terraenovae, the voltage-gated K+ currents involved in the action potential repolarization and repetitive firing of the neurons by way of the Kv channel inhibitors, 4-aminopyridine and 5-hydroxytryptamine.The receptor potential and the spike activity were simultaneously recorded from the ‘salt’, ‘sugar’ and ‘deterrent’ cells, by means of the extracellular side-wall technique, in response to 150mM NaCl, 100mM sucrose and 1mM quinine HCl, before, 0÷10min after apical administration of 4-AP (0.01–10mM) or 5-HT (0.1–100mM).The results show that the receptor potential in all three cells is neither affected by 4-AP nor by 5-HT. Instead, spike activity is significantly decreased, by way of blocking different Kv channel types: an inactivating A-type K+ current (KA) modulating repetitive firing of the cells and responsible for the after hyperpolarization, and a sustained K+ current that resembles the delayed rectifier (DKR) and contributes to action potential repolarization.

Decreased Intake of Sucrose Solutions in Orexin Knockout Mice

Orexins are synthesized by lateral hypothalamic neurons and are suggested to be implicated in feeding behavior. Recent studies have shown that intracerebroventricular administration of orexin-A increases intake of sweet-tasting solution. Effects of suppressing the orexin system on consumption of sweet-tasting solution and sensory processing with sweet taste inputs, however, have yet to be examined. We examined the effects of orexin deficiency on sucrose solution intake, locomotor activity, and preference for sweet solution using male orexin knockout (OxKO) and littermate wild-type (WT) mice. In the dark and over 24-h periods, OxKO mice showed significantly less sucrose intake and lower locomotor activity than WT mice without alteration in food intake whereas preferences for 100mM sucrose were not different between the genotypes. Moreover, sucrose intake of OxKO mice was significantly less than sucrose intake of a subgroup of WT mice with similar locomotor activity compared to that of OxKO mice. These results suggest that factors other than the lower energy expenditure due to lower locomotor activity are likely responsible for the decreased sucrose intake of OxKO mice. Orexin deficiency may lower the satiety threshold resulting in reduced sucrose intake, without altering food intake.

In vitro flowering on leaf explants of Streptocarpus nobilis. The influence of culture medium components on vegetative and reproductive development

Streptocarpus nobilis (C.B. Clarke) became photoperiodically more responsive to short days with increasing age. Leaf explants from photoperiodically induced plants were all organogenically competent when cultured on Murashige and Skoog medium in 8-h photoperiods. Both vegetative and flower buds were developed; the maximum level of in vitro flowering occurred in response to 6-benzylaminopurine (BAP), but only 50% of the explants produced flowers. 3-Indoleacetic acid (IAA) (1 × 10−7 to 1 × 10−6 M) inhibited in vitro flowering. A nutrient medium was devised which allowed the expression of flowering on 100% of explants. The expression of vegetative or reproductive development was strongly influenced by the concentrations of media nutrients. On high-KNO3 (20 mM) – high-sucrose (100 mM) medium vegetative development was favoured and flower buds were produced on only 28% of explants. On low-KNO3 (2 mM) – low-sucrose (15 mM) medium only flower buds were developed on all explants. On low-KNO3 (5 mM) medium organogenesis was also affected quantitatively by the sucrose concentration; organogenesis was reduced from 90% explant response on 25-mM sucrose medium to 52% explant response on 100-mM sucrose medium. The most rapid flowering response to low-KNO3 (2 mM) – low-sucrose (15 mM) medium was obtained on explants from leaves of axillary branches. Flower buds were formed on the main vein at the proximal region of the explant. This high response at a predictable location provides a useful system for investigating flowering.