The relative conformational stability of the alcohol dehydrogenase alleloenzymes of the fruitfly Drosophila melanogaster.

Intact spermatozoa from rat cauda epididymides possess an ecto-(cyclic AMP-dependent protein kinase) activity that causes the transfer of the terminal phosphate group of ATP to the serine residues of all the histone fractions. The enzyme showed a high degree of substrate specificity for the phosphorylation of histones rather than protamine, casein and phosvitin. The cell-external-surface protein kinase requires Mg2+ for activity, and other bivalent cations such as Mn2+ and Co2+ can substitute partially for Mg2+, whereas Ca2+ and Zn2+ are potent inhibitors of the enzyme. The enzyme has markedly higher affinity for cyclic AMP than for other cyclic nucleotides for its activation, with an apparent Km value for cyclic AmP of 80 nM. Spermatozoal ecto-kinase activity is not due to contamination of broken cells or any possible cell damage during incubation and isolation of spermatozoa. There was no loss of kinase activity from the cells when washed with 2 mM-EDTA, and the histones phosphorylated by intact spermatozoa were located outside the cells. Protein kinase activity of intact cells was strongly inhibited (approx. 90%) by p-chloromercuribenzenesulphonic acid (10 microM), which is believed not to enter the cells. These data provide further support for the localization of a protein kinase on the external surface of spermatozoa.     

Willow leaves' extracts contain anti-tumor agents effective against three cell types

Many higher plants contain novel metabolites with antimicrobial, antifungal and antiviral properties. However, in the developed world almost all clinically used chemotherapeutics have been produced by in vitro chemical synthesis. Exceptions, like taxol and vincristine, were structurally complex metabolites that were difficult to synthesize in vitro. Many non-natural, synthetic drugs cause severe side effects that were not acceptable except as treatments of last resort for terminal diseases such as cancer. The metabolites discovered in medicinal plants may avoid the side effect of synthetic drugs, because they must accumulate within living cells. The aim here was to test an aqueous extract from the young developing leaves of willow (Salix safsaf, Salicaceae) trees for activity against human carcinoma cells in vivo and in vitro. In vivo Ehrlich Ascites Carcinoma Cells (EACC) were injected into the intraperitoneal cavity of mice. The willow extract was fed via stomach tube. The (EACC) derived tumor growth was reduced by the willow extract and death was delayed (for 35 days). In vitro the willow extract could kill the majority (75%-80%) of abnormal cells among primary cells harvested from seven patients with acute lymphoblastic leukemia (ALL) and 13 with AML (acute myeloid leukemia). DNA fragmentation patterns within treated cells inferred targeted cell death by apoptosis had occurred. The metabolites within the willow extract may act as tumor inhibitors that promote apoptosis, cause DNA damage, and affect cell membranes and/or denature proteins.     

Seed-coat microsculpturing and its systematic application in Isatis (Brassicaceae) and allied genera in Iran

In order to examine the systematic application of seed-coat microsculpturing in Isatis, seed surfaces of 23 species (41 populations) in four genera of tribe Isatideae were examined using scanning electron microscopy (SEM). Eight types of basic ornamentation patterns were recognized among the studied specimens. Of these, the reticulate–areolate type was the most common and was found in the genera Isatis, Pachypterygium, Samerari and Tauscheria and 15 species (e.g., I. cappodocica, I. kotschyana and I. tinctoria). The reticulate type, the second most frequent, occurred in 7 species while other types each were represented by only one or 2 species. Although different populations of a given species show similar seed-surface sculpturing in most cases, in some polymorphic species like I. cappadocica and I. kotschyana these patterns were variable among populations. To some extent the variation corresponds to infraspecific taxa for some species, but the differences are not significant enough to be useful in the delimitation of the subspecies recognized by previous workers. Moreover, seed-coat characters do not support the separation of genera Isatis, Pachypterygium, Sameraria and Tauscheria.     

Cloning, molecular characterization and expression of a DNA-ligase from a new bacteriophage: Phax1

DNA ligases join 3′ hydroxyl and 5′ phosphate ends in double stranded DNA and are necessary for maintaining the integrity of genome. The gene encoding a new Escherichia phage (Phax1) DNA ligase was cloned and sequenced. The gene contains an open reading frame with 1,428 base pairs, encoding 475 amino acid residues. Alignment of the entire amino acid sequence showed that Phax1 DNA ligase has a high degree of sequence homology with ligases from Escherichia (vB_EcoM_CBA120), Salmonella (PhiSH19 and SFP10), Shigella (phiSboM-AG3), and Deftia (phiW-14) phages. The Phax1 DNA ligase gene was expressed under the control of the T7lac promoter on the pET-16b (+) in Escherichia coli Rossetta gami. The enzyme was then homogeneously purified by a metal affinity column. Enzymatic activity of the recombinant DNA ligase was assayed by an in-house PCR-based method.     

Nrf2 as a target for prevention of age‐related and diabetic cataracts by against oxidative stress

Cataract is one of the most important causes of blindness worldwide, with age‐related cataract being the most common one. Agents preventing cataract formation are urgently required. Substantial evidences point out aggravated oxidative stress as a vital factor for cataract formation. Nuclear factor (erythroid‐derived 2)‐like 2 (Nrf2)/Kelch‐like erythroid‐cell‐derived protein with CNC homology (ECH)‐associated protein 1 (Keap1) system is considered as one of the main cellular defense mechanisms against oxidative stresses. This review discusses the role of Nrf2 pathway in the prevention of cataracts and highlights that Nrf2 suppressors may augment oxidative stress of the lens, and Nrf2 inducers may decrease the oxidative stress and prevent the cataract formation. Thus, Nrf2 may serve as a promising therapeutic target for cataract treatment.     

eSGA: E. coli synthetic genetic array analysis

Physical and functional interactions define the molecular organization of the cell. Genetic interactions, or epistasis, tend to occur between gene products involved in parallel pathways or interlinked biological processes. High-throughput experimental systems to examine genetic interactions on a genome-wide scale have been devised for Saccharomyces cerevisiae, Schizosaccharomyces pombe, Caenorhabditis elegans and Drosophila melanogaster, but have not been reported previously for prokaryotes. Here we describe the development of a quantitative screening procedure for monitoring bacterial genetic interactions based on conjugation of Escherichia coli deletion or hypomorphic strains to create double mutants on a genome-wide scale. The patterns of synthetic sickness and synthetic lethality (aggravating genetic interactions) we observed for certain double mutant combinations provided information about functional relationships and redundancy between pathways and enabled us to group bacterial gene products into functional modules.