Male- and female-specific variants of doublesex gene products have different roles to play towards regulation of Sex combs reduced expression and sex comb morphogenesis in Drosophila

Sexually dimorphic characters have two-fold complexities in pattern formation as they have to get input from both somatic sex determination as well as the positional determining regulators. Sex comb development in Drosophila requires functions of the somatic sex-determining gene doublesex and the homeotic gene Sex combs reduced. Attempts have not been made to decipher the role of dsx in imparting sexually dimorphic expression of SCR and the differential function of sex-specific variants of dsx products in sex comb development. Our results in this study indicate that male-like pattern of SCR expression is independent of dsx function, and dsx ^F must be responsible for bringing about dimorphism in SCR expression, whereas dsx ^M function is required with Scr for the morphogenesis of sex comb.     

Acute outcome of treating patients admitted with electrical storm in a tertiary care centre

Background

Electrical storm (ES) is a life threatening emergency. There is little data available regarding acute outcome of ES.

Aims

The study aimed to analyze the acute outcome of ES, various treatment modalities used, and the factors associated with mortality.

Methods

This is a retrospective observational study involving patients admitted with ES at our centre between 1/1/2007 and 31/12/2013.

Results

41 patients (mean age 54.61 ± 12.41 years; 86.7% males; mean ejection fraction (EF) 44.51 ± 16.48%) underwent treatment for ES. Hypokalemia (14.63%) and acute coronary syndrome (ACS) (14.63%) were the commonest identifiable triggers. Only 9 (21.95%) patients already had an ICD implanted. Apart from antiarrhythmic drugs (100%), deep sedation (87.8%), mechanical ventilation (24.39%) and neuraxial modulation using left sympathetic cardiac denervation (21.95%) were the common treatment modalities used. Thirty-three (80.49%) patients could be discharged after a mean duration of 14.2 ± 2.31 days. Eight (19.5%) patients died in hospital. The mortality was significantly higher in those with EF < 35% compared to those with a higher EF (8 (42.11% vs 0 (0%), p = 0.03)). There was no significant difference in mortality between those with versus without a structural heart disease (8 (21.1% vs 0 (0%), p = 0.32)). Comparison of mortality an ACS with ES versus ES of other aetiologies (3 (50%) vs 5 (14.29) %, p = 0.076)) showed a trend towards significance.

Conclusion

With comprehensive treatment, there is reasonable acute survival rate of ES. Hypokalemia and ACS are the commonest triggers of ES. Patients with low EF and ACS have higher mortality.     

Influence of carbon and nitrogen sources on glucoamylase production byAspergillus in batch process

Summary Glucoamylase production kinetics was greatly affected by medium composition. While maltose and cassava flour induced glucoamylase synthesis, fructose clearly repressed it, reaching a maximum enzyne activity value (A_m) of only 6% of those obtained with the former carbon sources. Among the nitrogen sources the best result was obtained with urea, reaching A_m values of about 40% higher than those obtained with ammonium sulphate.     

Effect of yeast extract on Escherichia coli growth and acetic acid production

Fed batch cultures were performed to investigate the effect of yeast extract concentration on the kinetics of growth and acetic acid production of recombinant Escherichia coli BL21 in a synthetic medium. Three runs were performed with 40g/l total glucose concentration. The yeast extract/glucose ratio (YE/G; w/w), was 0.1, 0.05 and 0.025 in the feed. These decreasing YE/G values did not affect growth kinetics, but reduced the final cell concentration by about 10%, and also reduced the cell yield. Experiments with 60g/l total glucose concentration, one with a YE/G of 0.025 in the feed and the other without yeast extract, showed final acetic acid concentrations of 5.1 and 0.5g/l respectively, without any difference in cellular concentration. Although there was no significant influence on growth kinetics and final cellular concentration, the cell fermentative capacity was enhanced by yeast extract. The feed medium without yeast extract was the best condition for control purposes in high cell density cultures and for recombinant gene expression.     

Comparative study of Lowry and Bradford methods: interfering substances

The methods of Lowry and Bradford, commonly used for protein determination, were compared regarding the level of interference of some substances used for glucoamylase precipitation by ethanol. The method of Bradford suffers no interference while the method of Lowry showed protein concentration values 20% increased in the presence of ethanol and Tris. Despite these interferences, the Lowry method can evaluate more accurately the increase of purity during fractionation, due to its sensitivity to low molecular weight (below 6 kDa) proteins and peptides.     

Separation and purification of glucoamylase in aqueous two-phase systems by a two-step extraction

Extraction in two steps of glucoamylase was studied in poly(ethylene glycol) (PEG) and potassium phosphate systems at pH values of 6, 7 and 9. Ten different conditions using PEG 300, 600, 1500, 4000 and 6000 were studied. The bottom phase of the first extraction step, with the enzyme, was reused in an appropriate concentration of PEG to form the second extraction step. The optimal partitioning conditions for glucoamylase separation were obtained in PEG 4000 (first step), PEG 1500 (second step) at pH 7 and resulted in a three-fold increase in glucoamylase purification.     

Effect of pH on citrinin and red pigments production by Monascus purpureus CCT3802

The production of red pigments and citrinin by Monascus purpureus CCT3802 was investigated in submerged batch cultures performed in two phases: in the first phase, cells were grown on glucose, at pH 4.5, 5.5 or 6.5; after glucose depletion, pH was adjusted, when necessary, to 4.5, 5.5, 6.5, 7.0, 8.0 or 8.5, for a production phase. The highest total red pigments absorbance of 11.3 U was 16 times greater than the lowest absorbance and was achieved with growth at pH 5.5, followed by production at pH 8.5, which causes an immediate reduction of the intra cellular red pigments from 75% to 17% of the total absorbance. The lowest citrinin concentration, 5.5 mg L⁻¹, was verified in the same culture while the highest concentration, 55 mg L⁻¹, was verified in cultures entirely carried out at pH 5.5. An alkaline medium, besides promoting intra cellular red pigments excretion, strongly represses citrinin synthesis.     

Retroviral transfer of the p16INK4a cDNA inhibits C6 glioma formation in Wistar rats

BACKGROUND: The p16INK4A gene product halts cell proliferation by preventing phosphorylation of the Rb protein. The p16INK4a gene is often deleted in human glioblastoma multiforme, contributing to unchecked Rb phosphorylation and rapid cell division. We show here that transduction of the human p16INK4a cDNA using the pCL retroviral system is an efficient means of stopping the proliferation of the rat-derrived glioma cell line, C6, both in tissue culture and in an animal model. C6 cells were transduced with pCL retrovirus encoding the p16INK4a, p53, or Rb genes. These cells were analyzed by a colony formation assay. Expression of p16INK4a was confirmed by immunohistochemistry and Western blot analysis. The altered morphology of the p16-expressing cells was further characterized by the senescence-associated beta-galactosidase assay. C6 cells infected ex vivo were implanted by stereotaxic injection in order to assess tumor formation. RESULTS: The p16INK4a gene arrested C6 cells more efficiently than either p53 or Rb. Continued studies with the p16INK4a gene revealed that a large portion of infected cells expressed the p16INK4a protein and the morphology of these cells was altered. The enlarged, flat, and bi-polar shape indicated a senescence-like state, confirmed by the senescence-associated beta-galactosidase assay. The animal model revealed that cells infected with the pCLp16 virus did not form tumors. CONCLUSION: Our results show that retrovirus mediated transfer of p16INK4a halts glioma formation in a rat model. These results corroborate the idea that retrovirus-mediated transfer of the p16INK4a gene may be an effective means to arrest human glioma and glioblastoma.     

ATPS applied to extraction of small molecules - polycetides - and simultaneous clarification of culture media with filamentous microorganisms

Aqueous two-phase systems (ATPS) were applied for extraction of small molecules (polycetides) - retamycin, an anthracyclin, and two red pigments, rubropunctamin and monascorubramin - from the whole culture media of Streptomyces olindensis and Monascus purpureus. ATPS allows, in one step, the separation of the small hydrophobic molecules in the PEG rich phase, from the filamentous microorganisms, which remains in the salt phase. Through experimental designs, the main variables and their levels were defined, as follows: for retamycin extraction, PEG 6000 (10%, w/w), phosphate at 20% (w/w) and pH 6.0 led to the higher partition coefficient, K(r) = 8.2, and yield = 91.3%; for red pigments, the statistical analysis indicate PEG 6000 (20%, w/w) and phosphate at 15% (w/w), for a high partition coefficient, (K(pig) = 113 and 150).