Corroles that bind with high affinity to both apo and holo transferrin

The interactions of transferrin (Tf) with the water soluble corrole 1 and with its gallium (1-Ga) and manganese (1-Mn) complexes were studied to establish the possible utilization of corrole-transferrin conjugates for targeting these corroles to cells that express the transferrin receptor. The protein, in both its iron-free apo form (apoTf) and the iron-bound holo form (holoTf), was found to spontaneously bind all three derivatives. This conclusion was reached from titrations followed by several spectroscopic methods and dilution experiments measured by fluorescence. The such elucidated very small dissociation constant of 2 x 10(-7) M and 3 x 10(-8) M for 1-Ga with apoTf and holoTf, respectively and <10(-9) M for 1 with both protein forms are clearly relevant for the physiological concentration of transferrin in serum.     

Physiological and phylogenetic diversity of thermophilic spore-forming hydrocarbon-oxidizing bacteria from oil fields

The distribution and population density of aerobic hydrocarbon-oxidizing bacteria in the high-temperature oil fields of Western Siberia, Kazakhstan, and China were studied. Seven strains of aerobic thermophilic spore-forming bacteria were isolated from the oil fields and studied by microbiological and molecular biological methods. Based on the 16S rRNA gene sequences, phenotypic characteristics, and the results of DNA-DNA hybridization, the taxonomic affiliation of the isolates was tentatively established. The strains were assigned to the first and fifth subgroups of the genusBacillus on the phylogenetic branch of the gram-positive bacteria. Strains B and 421 were classified asB. licheniformis. Strains X and U, located betweenB. stearothermophilus andB. thermocatenulatus on the phylogenetic tree, and strains K, Sam, and 34, related but not identical toB. thermodenitrificans andB. thermoleovorans, undoubtedly represent two new species. Phylogenetically and metabolically related representatives of thermophilic bacilli were found to occur in geographically distant oil fields     

Social isolation improves working memory at reversal but not primary radial-arm maze learning in rats

Social isolation starting from the 21st day of birth affected neither a short-term nor a long-term memory in male rats at primary acquisition learning in an 8-arm radial maze. A number of the short-term and long-term memory errors were substantially decreased during primary learning but the difference between groups was not significant. Isolates were faster to start a search in an individual trial and took less time to finish offa trial. During the reversal learning, when baited and non-baited arms were reversed, the isolates outperformed of socially reared rats on working but not reference memory task. In overall they made twice less working memory errors than socially reared animals. During the reversal learning the isolates were also faster than non-isolates in initiation and completion of a trial. Maternal separation of rat's pups on the postnatal days 1-21 for 4 hr per day did not affect either working or reference memory on both primary and reversal learning. The data obtained are discussed on basis of influence of stress in early postnatal life on hypothalamo-pituitary axis and its effects on behavior of adult animals.     

Accurate inclusion mass screening: a bridge from unbiased discovery to targeted assay development for biomarker verification

Verification of candidate biomarker proteins in blood is typically done using multiple reaction monitoring (MRM) of peptides by LC-MS/MS on triple quadrupole MS systems. MRM assay development for each protein requires significant time and cost, much of which is likely to be of little value if the candidate biomarker is below the detection limit in blood or a false positive in the original discovery data. Here we present a new technology, accurate inclusion mass screening (AIMS), designed to provide a bridge from unbiased discovery to MS-based targeted assay development. Masses on the software inclusion list are monitored in each scan on the Orbitrap MS system, and MS/MS spectra for sequence confirmation are acquired only when a peptide from the list is detected with both the correct accurate mass and charge state. The AIMS experiment confirms that a given peptide (and thus the protein from which it is derived) is present in the plasma. Throughput of the method is sufficient to qualify up to a hundred proteins/week. The sensitivity of AIMS is similar to MRM on a triple quadrupole MS system using optimized sample preparation methods (low tens of ng/ml in plasma), and MS/MS data from the AIMS experiments on the Orbitrap can be directly used to configure MRM assays. The method was shown to be at least 4-fold more efficient at detecting peptides of interest than undirected LC-MS/MS experiments using the same instrumentation, and relative quantitation information can be obtained by AIMS in case versus control experiments. Detection by AIMS ensures that a quantitative MRM-based assay can be configured for that protein. The method has the potential to qualify large number of biomarker candidates based on their detection in plasma prior to committing to the time- and resource-intensive steps of establishing a quantitative assay.     

Functional expression of the Candida albicans alpha-factor receptor in Saccharomyces cerevisiae

Candida albicans genes involved in mating have been identified previously by homology to Saccharomyces cerevisiae mating pathway components. The C. albicans genome encodes CaSte2p, a homolog of the S. cerevisiae alpha-mating pheromone receptor Ste2p, and two potential pheromones, alpha-F13 (GFRLTNFGYFEPG) and alpha-F14 (GFRLTNFGYFEPGK). The response of several C. albicans strains to the synthesized peptides was determined. The alpha-F13 was degraded by a C. albicans MTLa strain but not by S. cerevisiae MATa cells. The CaSTE2 gene was cloned and expressed in a ste2-deleted strain of S. cerevisiae. Growth arrest and beta-galactosidase activity induced from a FUS1-lacZ reporter construct increased in a dose-dependent manner upon exposure of transgenic S. cerevisiae to alpha-F13. Mating between the strain expressing CaSTE2 and an opposite mating type was mediated by alpha-F13 and not by the S. cerevisiae alpha-factor. The results indicated that CaSte2p effectively coupled to the S. cerevisiae signal transduction pathway. Functional expression of CaSte2p in S. cerevisiae provides a well-defined system for studying the biochemistry and molecular biology of the C. albicans pheromone and its receptor.     

Geobacillus jurassicus sp. nov., a new thermophilic bacterium isolated from a high-temperature petroleum reservoir, and the validation of the Geobacillus species

Four thermophilic, spore-forming bacterial strains, DS1(T), DS2, 46 and 49, were isolated from the high-temperature Dagang oilfield, located in China. The strains were identified by using the polyphasic taxonomy approach. These were aerobic, gram-positive, rod-shaped, moderately thermophilic (with an optimum growth temperature of 60-65 degrees C), chemoorganotrophic bacteria capable of growing on various sugars, carboxylic acids and crude oil. Two strains, DS1(T) and DS2, were capable of growing on individual saturated hydrocarbons. The G + C content of the DNA of strains DS1(T) and DS2 was 54.5 and 53.8 mol%, respectively. The phylogenetic analysis of the 16S rDNA of strains DS1(T) and DS2 showed that they form a separate cluster within the genus Geobacillus. The cellular fatty acids of the isolates were dominated by iso-15:0, iso-16:0 and iso-17:0 acids, which are the typical fatty acids of bacteria from the genus Geobacillus. The DNA-DNA hybridization study and the comparative analysis of the morphological and chemotaxonomic characteristics of strains DS1(T) and DS2 showed that they differ from the previously described Geobacillus species and belong to a new species, which was called Geobacillus jurassicus. DS1(T) (=VKM B2301(T), = DSM 15726(T)) is the type strain of this species. According to both DNA-DNA reassociation studies and 16S rDNA sequence analysis, two other strains, 46 and 49, were assigned to the species G. stearothermophilus. In this paper, we provide evidence that the new combinations G. stearothermophilus, G. thermoleovorans, G. kaustophilus, G. thermoglucosidasius and G. thermodenitrificans may be considered to be valid.     

Effect of vibrissae removal on search accuracy in the water maze

In two experiments the vibrissae were clipped on either the left, the right or both sides, and the rats were trained to find a submerged platform in the Morris water maze. In both experiments, animals without vibrissae on both sides or on the left consistently spent significantly more time in the 'counter' area twice the platform diameter in size, surrounding the submerged platform, than intact controls. Counter preference was not as consistent across experiments in rats with right vibrissae removed. These results suggest that the vibrissae are required for proprioceptive location of the platform itself, but not for proximal search accuracy. Since ischaemic damage to hippocampal CA1 pyramidal cells has also been reported to prolong counter search during training, the results support the suggestion that impaired hippocampal processing of proprioceptive information from the vibrissae may contribute to the increased latency to find the platform shown by ischaemic rats.     

Stacking and hydrogen bonding: DNA cooperativity at melting

By taking into account base-base stacking interactions we improve the Generalized Model of Polypeptide Chain (GMPC). Based on a one-dimensional Potts-like model with many-particle interactions, the GMPC describes the helix-coil transition in both polypeptides and polynucleotides. In the framework of the GMPC we show that correctly introduced nearest-neighbor stacking interactions against the background of hydrogen bonding lead to increased stability (melting temperature) and, unexpectedly, to decreased cooperativity (maximal correlation length). The increase in stability is explained as due to an additional stabilizing interaction (stacking) and the surprising decrease in cooperativity is seen as a result of mixing of contributions of hydrogen bonding and stacking.