Regulation of trehalose metabolism by Adox and AdoMet in Saccharomyces cerevisiae

Effect of a potent methylation inhibitor oxidized adenosine (Adox), and a universal methyl group donor S-adenosyl-L-methionine (AdoMet) on trehalose metabolism was studied in two haploids of S. cerevisiae of mating types MATalpha, met3 (6460 -8D) and MATa, leu2, ura3, his4 (8534 -10A). Trehalose level decreased in presence of Adox in both strains. Both neutral trehalase (NT) and trehalose-6-phosphate (tre-6-p) synthase activities increased in presence of Adox in -8D strain. Decrease in trehalose level in -8D thus could not be explained in the light of increased tre-6-p synthase activity; however, it could be correlated with increased NT activity. In strain -10A, NT activity was reduced in presence of Adox while tre-6-p synthase activity increased. Enzyme activity profiles in -10A thus do not explain the reduced trehalose level on Adox treatment. Effect of AdoMet was not very prominent in either strain, though in -8D a small increase in trehalose level was seen on treatment. Intracellular AdoMet level of untreated cells of -10A was seen to be almost six times higher than that of -8D. Further, AdoMet treatment caused increase in its level compared to untreated cells, suggesting AdoMet uptake. No effect of either compound was seen on acid trehalase (AT) activity in any strain. The results suggest that there was a possible effect of demethylation on trehalose metabolism (particularly in the synthetic direction) in both strains, though effect of methylation was not very prominent, the reason for which is not very clear.     

Reactivity of [Ru(pac)(H2O)] (pac = polyaminocarboxylate) complexes with 5′-nucleotides and their antitumor activity

The reaction of [Ru^III(edta)(H₂O)]⁻ (edta⁴⁻ = ethylenediaminetetraacetate) and [Ru^III(hedtra)(H₂O)] (hedtra³⁻ = N-hydroxyethylethylenediaminetriacetate) with various purine based 5′-nucleotides (Nu) viz. adenosin-5′-monophosphate (AMP), guanosin-5′-monophosphate (GMP), inosin-5′-monophosphate (IMP) was studied kinetically as a function of [Nu] at various temperatures (15-35 °C) at a fixed pH (4.5). Kinetic results suggest that the binding of 5′-nucleotides takes place in a rapid [Nu] dependent rate-determining step. Kinetic data and activation parameters are accounted for the operation of an associative mechanism. The antitumor activities of both [Ru^III(edta)(H₂O)]⁻ (1) and [Ru^III(hedtra)(H₂O] (2) have been evaluated using MCF-7 (breast cancer), NCI-H460 (lung cancer) and SF-268 (CNS) cell lines.     

The role of tRNA as a molecular spring in decoding, accommodation, and peptidyl transfer

Translation is the process by which the genetic information contained in mRNA is used to link amino acids in a predetermined sequential order into a polypeptide chain, which then folds into a protein. Transfer RNAs (tRNAs) are the adapter molecules designed to provide the "lookup" from codons to amino acids. Cryo-EM has provided evidence that the ribosome, as a molecular machine, undergoes many structural changes during translation. Recent findings show that the tRNA structure itself undergoes large conformational changes as well, and that the decoding process must be seen as a complex dynamic interplay between tRNA and the ribosome.     

Functional interaction between BLM helicase and 53BP1 in a Chk1-mediated pathway during S-phase arrest

Bloom's syndrome is a rare autosomal recessive genetic disorder characterized by chromosomal aberrations, genetic instability, and cancer predisposition, all of which may be the result of abnormal signal transduction during DNA damage recognition. Here, we show that BLM is an intermediate responder to stalled DNA replication forks. BLM colocalized and physically interacted with the DNA damage response proteins 53BP1 and H2AX. Although BLM facilitated physical interaction between p53 and 53BP1, 53BP1 was required for efficient accumulation of both BLM and p53 at the sites of stalled replication. The accumulation of BLM/53BP1 foci and the physical interaction between them was independent of gamma-H2AX. The active Chk1 kinase was essential for both the accurate focal colocalization of 53BP1 with BLM and the consequent stabilization of BLM. Once the ATR/Chk1- and 53BP1-mediated signal from replicational stress is received, BLM functions in multiple downstream repair processes, thereby fulfilling its role as a caretaker tumor suppressor.     

Sensorimotor integration: locating locomotion in neural circuits

Neural components of the circuits that transform sensory cues into changes in motor activities are largely unknown. Several recent studies have now functionally mapped the sensorimotor circuits responsible for locomotion behaviors under defined environmental conditions in the nematode Caenorhabditis elegans.     

Importance of Laccase in Vegetative Growth of Pleurotus florida

Mycelial culture of Pleurotus florida produced highest extracellular laccase in optimum growth medium. At least two laccases (L(inf1) and L(inf2)) were shown to be present in the culture filtrate. Low-laccase-yielding mutants with impaired L(inf2) activity had poor mycelial growth and could not form fruit body, whereas the revertants from the same mutants were similar to the parent in mycelial growth and fruit body formation.     

Effect of daytime aeration on the growth of Indian carp fingerlings

The effect of artificial daytime aeration on the growth of Indian major carp fingerlings ( Labeo rohtta, Catla catla, Cirrhinus mrigala ) was tested in production tanks using 5, 2.5 and 0 hours of dail aeration with a stocking density of 60,000 ha^- each and 5 hours of daily aeration at 100,000 ha^-1. Under similar stocking conditions, the total fish yields at the end of a seven months growth period in the tanks with 2.5 (2.93 kg) and 5 (1.92 kg) hours of aeration were more than 85 and 21 % higher than that of the control system (1.58 kg), respectively. This was attributable to the higher rates of net primary productivity of phytoplankton, lowered ammonium and nitrite values as well as low N/P ratio in the 2.5 hour aeration treatment compared with the rest of the treatment.

Zusammenfassung

Die Auswirkungen der Belüftung zur Tageszeit auf das Wachrtum von Jungfiscben indischer Karpfen
Die Wirkung täglicher Belüftung auf das Wachstum der Jungfische der wichtigsten indischen Karpfen ( Labeo rohita, Catla catla, Cirrhinus mrigala ) wurde in Produktionsbecken getestet, die nichr, 2,5 Stunden und 5 Stunden täglich belüftet wurden (Besatzdichte = 60.000 Stück ha^-1). In einem weiteren Experiment betrug die Besatzdichte 100.000 Stück pro ha bei 5 Stunden täglicher Belüftungsdauer. Bei vergleichbarer Besatzdichte waren die Fischerträge am Ende der sieben Monate dauernden Wachstumsperiode in den Becken mir 2,5 Stunden (2,93 kg) und 5 Stunden (1,92 k) Belüftung über 85%, bzw. 21 % höher als im Kontrollsystem (1,58 kg). Dies wurde in dem 2,5 Stunien Belüftungsexperiment der erhohten Netro-Primärproduktion des Phytoplanktons in den belüfteten Systemen zugeschrieben sowie den resultierenden geringeren Ammonium- und Nitritwerten und dem niedrigen N/P-Verhältnis.     

A rapid silver-free method for staining the myenteric plexus

A method is presented for the relatively rapid demonstration of the myenteric plexus. Saturated Sudan black B in 70% ethanol followed by 0.01% aqueous buffered thionein were used on intestinal peels (whole-mounts) to stain myelinated and unmyelinated fibers and neuron cell bodies, respectively. In contrast to accepted silver methods, these two kinds of fibers were distinguished clearly; Schwann cell nuclei and nodes of Ranvier were visible. Preparations had the following attributes: relatively low optical density coupled with high visual contrast, freedom from metallic "mirroring," low background staining of subjacent muscle fibers, and presentation of a polychromatic picture. The entire procedure was under the complete and repeatable control of the operator. Perikaryon and nuclear morphology were clearly demonstrated. The limitations of this method are that it does not provide good visualization of individual unmyelinated neuronal processes and does not permit preparation of permanent slides.     

Novel heterophile chicken antigen: immunohistochemical localization using antisera to Mycobacterium smegmatis and possible association with lymphocyte maturation

Summary A novel heterophile antigen shared byMycobacterium smegmatis and chicken tissues was demonstrated by the indirect immunoperoxidase method using antisera raised in rabbits immunized with a complete Freund's adjuvant containing killedMycobacterium smegmatis as an immunostimulating component. This antigen was strongly expressed in medullary lymphocytes of the thymus and bursa of Fabricius, but was undetectable in lymphoid cells of the cortical regions of these organs. Only a few lymphocytes stained positively for the antigen in T- and B-cell areas of the spleen. These data suggest that the heterophile antigen is associated with the intrathymic and intrabursal maturation of chicken lymphocytes. The antigen was also detected in some nonlymphoid cells. It was not found in sheep erythrocytes, human and rat tissues or in killed bacillus Culmette—Guerin.