Evaluation of homology between cloned Escherichia coli and yeast DNA photolyase genes and higher eukaryotic genomes

Repair of ultraviolet-induced pyrimidine dimers by photoreactivation is catalyzed by a single enzyme, DNA photolyase. However, the process of photoreactivation is difficult to detect reproducibly in cultured mammalian cells. We have used clones containing yeast and Escherichia coli DNA photolyase genes to determine whether their sequences are conserved and whether there is homology between either cloned sequence and chick or human genomic DNA and mRNA sequences. The cloned sequences failed to hybridize to each other even under nonstringent conditions, indicating little conservation of sequence between the yeast and E. coli genes. Furthermore, only weak hybridization under nonstringent conditions was found between the cloned photoreactivating genes and human or chick genomic DNA or mRNA. This indicates that there is negligible homology between the cloned probes and mammalian DNA, but we are unable to conclude whether this indicates sequence divergence for prokaryotic and eukaryotic photoreactivation genes or the absence of such genes from the mammalian genome.     

Neural structures associated with recognition of facial expressions of basic emotions.

People with Huntington''s disease and people suffering from obsessive compulsive disorder show severe deficits in recognizing facial expressions of disgust, whereas people with lesions restricted to the amygdala are especially impaired in recognizing facial expressions of fear. This double dissociation implies that recognition of certain basic emotions may be associated with distinct and non-overlapping neural substrates. Some authors, however, emphasize the general importance of the ventral parts of the frontal cortex in emotion recognition, regardless of the emotion being recognized. In this study, we used functional magnetic resonance imaging to locate neural structures that are critical for recognition of facial expressions of basic emotions by investigating cerebral activation of six healthy adults performing a gender discrimination task on images of faces expressing disgust, fear and anger. Activation in response to these faces was compared with that for faces showing neutral expressions. Disgusted facial expressions activated the right putamen and the left insula cortex, whereas enhanced activity in the posterior part of the right gyrus cinguli and the medial temporal gyrus of the left hemisphere was observed during processing of angry faces. Fearful expressions activated the right fusiform gyrus and the left dorsolateral frontal cortex. For all three emotions investigated, we also found activation of the inferior part of the left frontal cortex (Brodmann area 47). These results support the hypotheses derived from neuropsychological findings, that (i) recognition of disgust, fear and anger is based on separate neural systems, and that (ii) the output of these systems converges on frontal regions for further information processing.     

Sequence homology between avian and human adenoviruses

Studies of hybridization between fowl adenovirus type 1 (chicken embryo lethal orphan virus) DNA and human adenovirus type 2 DNA revealed two short but distinct regions which cross-hybridized under stringent conditions. One of the homologous regions was located between map positions 18.1 and 19.3 and did not correspond to any gene recognized so far. The second region mapped in the hexon gene between position 57 and 58.     

RepFIC, a basic replicon of IncFI plasmids that has homology with a basic replicon of IncFII plasmids

It was found that a DNA segment containing genes for autonomous replication and its control (basic replicon) present in the IncFI plasmid P307 has homology with RepA, a basic replicon present in IncFII plasmids. The basic replicon in P307 is referred to as RepFIC and the homologous basic replicon in IncFII plasmids is referred to as RepFIIA. In 11 other IncFI plasmids studied a region that has homology with RepFIC and RepFIIA was demonstrated. Thus, of the several basic replicons present in IncFI plasmids, RepFIC is evolutionarily related to a basic replicon of IncFII plasmids.     

Sequence homology between bovine and human adenoviruses.

Cross-hybridization has been detected between corresponding regions of the genomes of bovine adenovirus type 3 and human adenovirus type 2. The most conserved region on the viral genomes encodes the hexon polypeptide. The nucleotide sequence of this region in bovine adenovirus type 3 has been determined. Comparison of the predicted amino acid sequences of the bovine adenovirus type 3 and human adenovirus type 2 hexon polypeptides reveals three regions of nonhomology.     

The cognitive set and problems of the human higher nervous activity

Two kinds of cognitive sets for verbal and non-verbal stimuli were revealed in healthy subjects: an "intellectual blindness" and a distortion of perception and assessment of the stimuli size. Analysis of the response time to a probe stimulus and a spectral analysis of the cortical EEG revealed a participation of these sets in cortical functions: a stable set organizes and improves the stimuli perception and assessment but impedes this process in a modified situation. An optimal balance between the two sets seems to be necessary for effective cognitive activity.     

Genetic homology between independently isolated chlorobenzoate-degradative plasmids

Two chlorobenzoate-degradative plasmids were studied by the hybridization of the restriction endonuclease-generated fragments of one plasmid after transfer to a nitrocellulose filter with nick-translated radioactive DNA of the other plasmid as a probe. Two strains harboring the 3-chlorobenzoic acid-degradative plasmids were isolated in two different parts of the world at two different times. The plasmids are now found to be closely related to each other by hybridization studies. The chlorobenzoate-degradative plasmid from Pseudomonas sp. strain B13 (termed pB13) has a 6-kilobase deletion but otherwise is homologous with previously described plasmid pAC25.     

Sequence homology between human and animal rotavirus serotype-specific glycoproteins

The dsRNA gene segment coding for the major outer shell glycoprotein of a human rotavirus (Hu/Australia/5/77, serotype 2) was converted into DNA and cloned into the PstI site of the plasmid pBR322. The cloned gene was sequenced and found to be 1062 bp long with one long open reading frame capable of coding for a protein 326 amino-acids. When this gene sequence was compared to the published sequences of the corresponding genes of two animal rotaviruses, SA11 (simian) and UK (bovine), all three were found to be closely related (74-78%). The predicted amino-acid sequences of the three genes were also highly conserved (75-86%), despite the fact that the three viruses belong to different serotypes.     

Cooperation in humans: competition between groups and proximate emotions

Understanding the ultimate and proximate mechanisms that favour cooperation remains one of the greatest challenges in the biological and social sciences. A number of theoretical studies have suggested that competition between groups may have played a key role in the evolution of cooperation within human societies, and similar ideas have been discussed for other organisms, especially cooperative breeding vertebrates. However, there is a relative lack of empirical work testing these ideas. Our experiment found, in public goods games with humans, that when groups competed with other groups for financial rewards, individuals made larger contributions within their own groups. In such situations, participants were more likely to regard their group mates as collaborators rather than competitors. Variation in contribution among individuals, either with or without intergroup competition, was positively correlated with individuals' propensity to regard group mates as collaborators. We found that the levels of both guilt and anger individuals experienced were a function of their own contributions and those of their group mates. Overall, our results are consistent with the idea that the level of cooperation can be influenced by proximate emotions, which vary with the degree of intergroup competition.     

Structural homology between mouse liver and horse spleen ferritins

Mouse liver ferritin is composed almost exclusively of polypeptide chains similar in molecular mass (22 kDa) to that characteristic of the major chain (H) found in heart ferritin isolated from human, horse or rat. In these species the predominant polypeptide of liver (L) is smaller (about 20 kDa). Here we show that mouse liver and horse spleen ferritins and apoferritins exhibit extensive structural homology as judged by the similarity in the diffraction patterns of their crystals grown from cadmium sulphate solutions. Implications of this finding are discussed.