Altered Diurnal Leaf Movements in Soybean Seedlings Treated with Triazole Growth Regulators

Treatment of two-week old soybean (Glycine max (L.) Merr. cv.A2) seedlings with 250 µg of either soil-applied paclobutrazolor XE-1019 (also known as S-3307) altered diurnal leaf movementswithin 48 h. Leaf blade and petiole angles of primary leaves,relative to the horizontal, were consistently lower in the triazole-treatedseedlings compared to controls during the daylight hours. Atnight, leaves were completely folded down in both treated andcontrol seedlings, but leaves on treated seedlings reached thefolded down position approximately two hours earlier than controls.A single foliar spray of 6.0 mg-liter^–1 GA₃ counteractedthe triazole effects on leaf blade and petiole angles. (Received February 25, 1987; Accepted July 21, 1987)     

Growth hormone and rat liver mitochondria effects on urea cycle enzymes

Effects of hypophysectomy and subsequent growth hormone administration on mitochondrial enzymes of the urea cycle were investigated in rat liver. Hypophysectomy increased the activities of the two mitochondrial enzymes, carbamyl phosphate synthetase and ornithine transcarbamylase but not of the cytosolic enzyme, argininosuccinate synthetase. The activity of mitochondrial phosphate dependent glutaminase was not affected. Administration of bovine growth hormone (100 μg/100 g body weight) for two weeks decreased the activities of carbamyl phosphate synthetase and ornithine transcarbamylase almost to the normal level. These results suggest a specific effect of growth hormone on mitochondrial enzymes of the urea cycle and serve to explain the increased urea formation in hypopituitarism.     

Low sugar and osmotic requirements for shoot regeneration from leaf pieces of Solanum melongena L.

Uniform leaf pieces of egg-plant, Solanum melongena L., were cultured in Murashige and Skoog's medium containing 2 mg l^-1 kinetin and varying sugar levels. Glucose or fructose at 44 mM was optimal in inducing shoot regeneration compared to sucrose. Sucrose at 11 and 22 mM induced more shoot organogenesis than at lower or higher levels. An additional 22 mM mannitol with 22 mM sucrose enhanced shoot regeneration significantly more than 22 mM sucrose alone. The dual role of sugar as carbon and osmotic source in shoot regeneration from leaf explants of egg-plant is discussed.     

Effects of reflex delays on postural control during unstable seated balance

Patients with low-back pain (LBP) exhibit longer trunk muscle reflex latencies and poorer postural control than healthy individuals. We hypothesized that balance during a simulated postural control task would become impaired when the delays exhibited by LBP patients were incorporated into neuromuscular control. The task chosen for this investigation was seated balancing, which emphasizes trunk muscles’ contribution in postural control. This task was modeled in Simulink? as a fourth order linearized dynamic system with feedback delays. Optimization (minimizing error between experimental and model data) of state variables was used to determine neuromuscular control parameters. Experimental data were obtained from 7 subjects during 5 perturbation trials while balancing on the seat with eyes closed. Model accuracy, reflecting the ability of the model to capture the dynamics of seated balance, was correlated with seated balance performance (r=0.91, p<0.001). To minimize the risk of erroneous findings from inaccurate modeling, only the best five balancers’ data were used for hypothesis testing. In these five subjects, feedback delays in modeled neuromuscular control were increased to determine their effect on task stability, trunk displacement and trunk moment. Simulations showed that longer delays found in LBP, in general, did not produce unstable balancing, but did result in increased trunk displacement (p<0.001) and trunk moment (p=0.001). This impairment in neuromuscular control in chronic LBP patients could possibly exacerbate their condition by increasing tissue strain (more spinal displacement) and stress (more spinal loading).     

Cellular and Neural Responses to Sour Stimuli Require the Proton Channel Otop1

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Formulation and evaluation of ethosomes for transdermal delivery of lamivudine

The purpose of the present research was to investigate the mechanism for improved intercellular and intracellular drug delivery from ethosomes using visualization techniques and cell line study. Ethosomal formulations were prepared using lamivudine as model drug and characterized in vitro, ex vivo and in vivo. Transmission electron microscopy, scanning electron microscopy, and fluorescence microscopy were employed to determine the effect of ethosome on ultrastructure of skin. Cytotoxicity and cellular uptake of ethosome were determined using T-lymphoid cell line (MT-2). The optimized ethosomal formulation showed 25 times higher transdermal flux (68.4 +/- 3.5 microg/cm(2)/h) across the rat skin as compared with that of lamivudine solution (2.8 +/- 0.2 microg/cm(2)/h). Microscopic studies revealed that ethosomes influenced the ultrastructure of stratum corneum. Distinct regions with lamellar stacks derived from vesicles were observed in intercellular region of deeper skin layers. Results of cellular uptake study showed significantly higher intracellular uptake of ethosomes (85.7% +/- 4.5%) as compared with drug solution (24.9% +/- 1.9%). The results of the characterization studies indicate that lipid perturbation along with elasticity of ethosomes vesicles seems to be the main contributor for improved skin permeation.     

Stability study of stavudine-loaded O-palmitoyl-anchored carbohydrate-coated liposomes

The purpose of this study was to evaluate the physicochemical stability of carbohydrate-anchored liposomes. In the present study, carbohydrate (galactose, fucose, and mannose) was palmitoylated and anchored on the surface of positively charged liposomes (PL). The stabilities of plain neutral liposomes (NL), PL, and O-palmitoyl carbohydrate-anchored liposomes were determined. The effects of storage conditions (4°C±2°C, 25°C±2°C/60%±5% relative humidity [RH], or 40°C±2°C/75%±5% RH for a period of 10, 20, and 30 days) were observed on the vesicle size, shape, zeta potential, drug content, and in vitro ligand agglutination assay by keeping the liposomal formulations in sealed ambercolored vials (10-mL capacity) after flushing with nitrogen. The stability of liposomal formulations was found to be temperature dependent. All the liposomal formulations were found to be stable at 4°C±2°C up to 1 month. Storage at 25°C±2°C/60%±5% RH and 40°C±2°C/75%±5% RH adversely affected uncoated liposomal formulations. Carbohydrate coating of the liposomes could enhance the stability of liposomes at 25°C±2°C/60%±5% RH and 40°C±2°C/75%±5% RH. Published: May 18, 2007