The effect of estrogen on the tubal epithelium of immature ovariectomized rhesus monkey (Macaca mulatta).

The effect of 3 doses of estradiol dipropionate (EDP) on tubal epithelium of immature ovariectomized rhesus monkey (Macaca mulatta) was studied under both light and electron microscopy. EDP at a dose of 5 microgram/kg/day for 6 consecutive days changed differentiation of the epithelial cells into clear and dark cell-types; ciliogenesis, formation of some ciliary buds and even a few cilia were also induced in some clear cells throughout the tubal epithelium. Development of ciliated cells with fully formed ciliary apparatus was accelerated at 10 microgram/kg dosage. The secretory granules (SG) appeared at this dose in some nonciliated cells of the infundibular and ampullary but not the isthmic segments of the tube; some of the infundibular secretory cells, so formed, exhibited even a tendency to secrete. Nearly complete maturation of the tubal epithelium occurred at 20 microgram/kg dose; further signs of secretory activity appeared in all tubal segments. The results indicated that--(i) Nearly complete transformation of tubal epithelium of the immature animal into one of the adult type could be achieved by EDP at a dose not less than 20 microgram/kg under the present conditions. (ii) The response of undifferentiated cells to EDP differed depending upon the location of the epithelial cell within the tube and nature of the cell-type to be formed. (iii) The mode of tubal secretion in this infra-human species was probably apocrine.     

Structural and functional changes in a synthetic S5 segment of KvLQT1 channel as a result of a conserved amino acid substitution that occurs in LQT1 syndrome of human

Mutations in various voltage gated cardiac ion channels are the cause of different forms of long QT syndrome (LQTS), which is an inherited arrhythmic disorder marked as a prolonged QT interval on electrocardiogram. Of these LQTS1 is associated with mutations in the gene encoding KCNQ1 (KvLQT1) channel. One responsible mutation, G269S, in the S5 segment of KvLQT1, that affects the proper expression and function of channel protein leads to LQTS1. Our objective was to study how G269S mutation interferes with the structure and function of a synthetic S5 segment of KvLQT1 channel. One wild type 22-residue peptide and another mutant peptide of the same length with G269S mutation, derived from the S5 segment were synthesized and labeled with fluorescent probes. The mutant peptide exhibited lower affinity towards phospholipid vesicles as compared to the wild type peptide and showed impaired assembly and localization onto the lipid vesicles as evidenced by membrane-binding, energy transfer and proteolytic cleavage experiments. Loss in the helical content of S5 mutant peptide in membrane-mimetic environments was observed. Furthermore, it was observed that G269S mutation significantly inhibited the ability of S5 peptide to permeabilize the lipid vesicles. The present studies show the basis of change in function of the selected S5 segment as a result of G269S mutation which is associated with LQT1 syndrome. We speculate that the structural and functional changes related to the glycine to serine amino acid substitution in the S5 segment may also influence the activity of the whole KvLQT1 channel.     

Immobilization of Kluyveromyces marxianus cells containing inulinase activity in open pore gelatin matrix: 1. Preparation and enzymatic properties

Kluyveromyces marxianus cells with inulinase (2,1-β-d-fructan fructanohydrolase, EC 3.2.1.7) activity have been immobilized in open pore gelatin pellets with retention of > 90% of the original activity. The open pore gelatin pellets with entrapped yeast cells were obtained by selective leaching out of calcium alginate from the composite matrix, followed by crosslinking with glutaraldehyde. Enzymatic properties of the gelatin-entrapped cells were studied and compared with those of the free cells. The immobilization procedure did not alter the optimum pH of the enzymatic preparation; the optimum for both free and immobilized cells was pH 6.0. The optimum temperature of inulin hydrolysis was 10°C higher for immobilized cells. Activation energies for the reaction with the free and immobilized cells were calculated to be 6.35 and 2.26 kcal mol^?1, respectively. K_m values were 8 mM inulin for the free cells and 9.52 mM for the immobilized cells. The thermal stability of the enzyme was improved by immobilization. Free and immobilized cells showed fairly stable activities between pH 4 and 7, but free cell inulinase was more labile at pH values below 4 and above 7 compared to the immobilized form. There was no loss of enzyme activity of the immobilized cells on storage at 4°C for 30 days. Over the same period at room temperature only 6% of the original activity was lost.     

Kinetics of ethanol production by immobilized cells of Zymomonas mobilis at varying d-glucose concentrations

Ethanol fermentation by cells of Zymomonas mobilis immobilized in calcium alginate gel has been studied using 5 to 30 wt% initial d-glucose in the medium. Up to 27% d-glucose was completely fermented and the maximum ethanol concentration of 12.6% (w/v) was obtained using an immobilized cell concentration of 58 g dry wt l^?1 of bead volume. The ethanol yield coefficient was almost unaffected by initial d-glucose concentration and its value was >95% of theoretical. The rates of ethanol production and d-glucose utilization first increased, with an increase in initial d-glucose concentration up to 13.6%, and then started to decrease upon a further increase in initial d-glucose concentration. Cell leakage from the calcium alginate beads was very low.     

Optimisation of culture conditions for production of eicosapentaenoic acid byMortierella elongate NRRL 5513

Summary WhenMortierella elongata NRRL 5513 was cultured in shake flasks at 25°C, mycelial growth reached a stationary phase at 48 h but maximum eicosapentaenoic acid (EPA) production was observed at 6 days. When incubated at 11°C, EPA production also continued to rise during the stationary phase of growth, reaching a maximum after 10 days. An initial culture pH of 6.1 was found to be optimum for EPA production. The effect of temperature on EPA production was dependent on medium constituents. In glucose and linseed oil supplemented media, optimum temperature for EPA production was 11 and 15°C respectively. A maximum EPA yield of 0.61 g/l was obtained in linseed oil (2%), yeast extract (0.5%) supplemented basal medium. Maximum EPA content as a percentage of lipids (15.12%) was observed when the latter medium was supplemented with 0.25% urea.     

Arachidonic Acid Production by Fungi

After preliminary screening, Mortierella alpina and Mortierella elongata were compared with respect to arachidonic acid content. M. alpina ATCC 16266 produced 2.1 g of arachidonic acid per liter in media containing 10% glucose while the highest percentage of arachidonic acid in lipid (43.3%) was observed at a glucose concentration of 2%. Arachidonic acid content in lipids increased to 66% during storage.     

Roles of Sugars in Controlling Flowering Time

Flowering time is influenced by environmental factors such as photosynthesis, temperature, nutrition, and water. The main products of photosynthesis are sugars that are mobilized to sink tissues to support plant growth and differentiation. They also function as signals to control various types of metabolism and developmental processes. One of the most important transitions in the plant life cycle is from the vegetative to reproductive phase. During that transition, sucrose levels rise rapidly but transiently in the phloem and shoot apexes. For several species, the addition of exogenous sucrose promotes flowering, possibly by acting as a main signal. Although other sugars, including glucose, also appear to be involved in this transition, evidence for their roles in flowering is limited. In Arabidopsis thaliana, trehalose-6-phosphate serves as a signal to induce flowering. However, its roles in other plants have not been reported. Sucrose seems to function primarily in the leaf phloem to enhance the generation of florigens such as Flowering Locus T (FT) while trehalose-6-phosphate functions in the shoot apical meristem to promote the flowering signal pathway downstream of those florigens.     

Numerical Simulation of Electromagnetic Wave Interaction with Spheroidal Core-Shell Nanoparticle: Dependence of Surface Plasmon Resonance on Core-Shell Composition

Plasmonics - In the present work, we report our observations drawn from the numerical simulation of absorption and scattering efficiencies of spheroid shape nanostructures using discrete dipole...     

Oxygen uptake rate as a tool for on-line estimation of cell biomass and bed temperature in a novel solid-state fermentation bioreactor

Bioprocess and Biosystems Engineering - Direct measurement of cell biomass is difficult in a solid-state fermentation (SSF) process involving filamentous fungi since the mycelium and the solid...     

Role of defective Ca<Superscript>2+</Superscript> signaling in skeletal muscle weakness: Pharmacological implications

The misbehaving attitude of Ca²⁺ signaling pathways could be the probable reason in many muscular disorders such as myopathies, systemic disorders like hypoxia, sepsis, cachexia, sarcopenia, heart failure, and dystrophy. The present review throws light upon the calcium flux regulating signaling channels like ryanodine receptor complex (RyR1), SERCA (Sarco-endoplasmic Reticulum Calcium ATPase), DHPR (Dihydropyridine Receptor) or Cav1.1 and Na+/Ca²⁺ exchange pump in detail and how remodelling of these channels contribute towards disturbed calcium homeostasis. Understanding these pathways will further provide an insight for establishing new therapeutic approaches for the prevention and treatment of muscle atrophy under stress conditions, targeting calcium ion channels and associated regulatory proteins.