Zacharias G. Scouras

Insecticidal effects of essential oils. A study of the effects of essential oils extracted from eleven Greek aromatic plants on Drosophila auraria

Effects of the essential oils (EOs) extracted from eleven aromatic plants belonging to the Lamiaceae family (common in the Greek flora) were examined upon three different developmental stages ofDrosophila auraria. All of the EOs examined exhibited insecticidal effects, either by preventing egg hatching, or by causing the death of larvae and adult flies. In several cases, malformation and/or prohibition of puparium formation was also observed.

Balbiani rings and puffs of the polytene chromosomes of Drosophila auraria

Drosophila auraria and its sibling species, D. biauraria, D. triauraria, and D. quadraria are unique among Drosophila species in that their salivary gland chromosomes exhibit Balbiani rings. In this report we present a cytological map of D. auraria and information on the developmental profiles of its puffs and Balbiani rings. Information is presented on the existence of tandem inverted duplications involving the Balbiani ring regions and other regions of the chromosomes, and data are given concerning the puffing patterns of the duplicated bands. Possible homologies between puffs of D. melanogaster and D. auraria and certain differences between the two species in the developmental sequences of the active loci are discussed.

Identification of several cytoplasmic HSP70 genes from the Mediterranean mussel (Mytilus galloprovincialis) and their long-term evolution in Mollusca and Metazoa.

The HSP70 protein family consists one of the most conserved and important systems for cellular homeostasis under both stress and physiological conditions. The genes of this family are poorly studied in Mollusca, which is the second largest metazoan phylum. To study these genes in Mollusca, we have isolated and identified five HSP70 genes from Mytilus galloprovincialis (Mediterranean mussel) and investigated their short-term evolution within Mollusca and their long-term evolution within Metazoa. Both sequence and phylogenetic analyses suggested that the isolated genes belong to the cytoplasmic (CYT) group of the HSP70 genes. Two of these genes probably represent cognates, whereas the remaining probably represent heat-inducible genes. Phylogenetic analysis including several molluscan CYT HSP70s reveals that the cognate genes in two species have very similar sequences and form intraspecies phylogenetic clades, differently from most metazoan cognate genes studied thus far, implying either recent gene duplications or concerted evolution. The M. galloprovincialis heat-inducible genes show intraspecies phylogenetic clustering, which in combination with the higher amino acid than nucleotide identity suggests that both gene conversion and purifying selection should be responsible for their sequence homogenization. Phylogenetic analysis including several metazoan HSP70s suggests that at least two types of CYT genes were present in the common ancestor of vertebrates and invertebrates, the first giving birth to the heat-inducible genes of invertebrates, whereas the other to both the heat-inducible genes of vertebrates and the cognate genes of all metazoans. These analyses also suggest that inducible and cognate genes seem to undergo divergent evolution.

Duplications in the polytene chromosomes of Drosophila auraria

A study of the salivary gland chromosomes of two strains of Drosophila auraria has revealed a suprisingly high number of inverted tandem duplications and one triplication. The possible origin and significance of these are discussed.

Using sign at power poles to document presence of bears in Greece

Abstract The endangered brown bear (Ursus arctos) population in Greece is in urgent need of effective protection and management; that management should be based on information that is both reliable and quickly attained. After observing bears marking and rubbing on power poles, we initiated a study to collect information on this behavior and develop an effective method for documenting bear presence in Greece. Thirty-nine power poles in the main study area were fitted with barbed wire and inspected monthly for a year. The information and experience gained in the main study area was used to survey 3 additional areas, covering a representative sample of the species distribution in the country. Power pole-related behaviors were associated with mud smears, hair deposits, and bite and claw marks (hereafter referred to as marks). Tracks and scats also have been used to document the presence of brown bears in Greece, but fewer of these were found in all areas surveyed. Deterioration rate of marks was slower than that of tracks and scats. Our results suggest that power pole-related behavior is not a localized phenomenon. A monitoring scheme in Greece documenting the presence of the species that would include the regular inspection of power poles could take advantage of the higher abundance and slower deterioration rate of power pole-related signs and be time efficient and easily staffed by volunteers. The ability to identify individual bears through genetic analysis of hair collected from power poles is an additional advantage of this approach.

A Drosophila hsp70 gene contains long, antiparallel, coupled open reading frames (LAC ORFs) conserved in homologous loci

A clone isolated from a Drosophila auraria heat-shock cDNA library presents two long, antiparallel, coupled (LAC) open reading frames (ORFs). One strand ORF is 1,929 nucleotides long and exhibits great identity (87.5% at the nucleotide level and 94% at the amino acid level) with the hsp70 gene copies of D. melanogaster, while the second strand ORF, in antiparallel in-frame register arrangement, is 1,839 nucleotides long and exhibits 32% identity with a putative, recently identified, NAD+-dependent glutamate dehydrogenase (NAD+-GDH). The overlap of the two ORFs is 1,824 nucleotides long. Computational analysis shows that this LAC ORF arrangement is conserved in other hsp70 loci in a wide range of organisms, raising questions about possible evolutionary benefits of such a peculiar genomic organization.

The ?-tubulin gene family evolution in the Drosophila montium subgroup of the melanogaster species group

The β1-, β2-, and β3-tubulin genes have been mapped by in situ hybridization on the polytene chromosomes of 11 selected species (15 strains) belonging to the Drosophila montium subgroup. Although the hybridization pattern among the strains of the same species does not differ, this pattern is significantly different among the species. The β-tubulin genes in the montium subgroup seem to be organized in a cluster, or in a semi-cluster, or are completely dispersed. The clustered arrangement is found in the North-Oriental sibling species D. auraria, D. triauraria, and D. quadraria. The semi-clustered arrangement, wherein the β1 and β2 genes are located at the same locus while β3 is at a different one, appears in the South-Oriental species D. bicomuta, D. serrata, and D. birchii, as well as in the Afrotropical species D. diplacantha and D. seguyi. The complete separation of the genes is observed in the Indian species D. kikkawai and D. jambulina and in the Afrotropical species D. vulcana. Based on the above results, a possible mode of evolution of the β-tubulin genes in the montium subgroup is attempted. In addition, phylogenetic relationships among the montium species are discussed.

Induction of a subgroup of acute phase protein genes in mouse liver by hyperthermia

We have demonstrated that two members of the acute phase reactant family of positively regulated genes, alpha 1-acid glycoprotein (AGP-1 and AGP-2) and C-reactive protein (CRP) are induced by hyperthermia, while two others, the serum amyloid A (SAA) and alpha 1-antitrypsin (AT) genes, are not. Albumin (ALB), a negative acute phase reactant gene, is also induced by hyperthermia. The AGP-1, AGP-2, and CRP genes require glucocorticoids, but not IL-6, IL-1 beta or TNF alpha in response to hyperthermia. As with LPS, the C/EBP beta mRNA levels increased, while the C/EBP alpha mRNA levels decreased in response to LPS. In contrast to the LPS response, C/EBP delta was unchanged. Protein pool levels and DNA-binding activities of the 35 and 20 kDa C/EBP beta isoforms increase, whereas protein pool levels of the 42 kDa C/EBP alpha decrease and the 30kDa remained high. These studies suggest that the synthesis of specific C/EBP alpha and C/EBP beta isoforms is induced by hyperthermia, and that the regulation of the AGP-1 and AGP-2 genes during heat stress may involve one of these isoforms. The difference between the responses to hyperthermia and LPS is that the former, may not involve the participation of cytokines. Furthermore, since cis-acting heat shock elements (HSE) are located in the promoter regions of the ALB, CRP, and C/EBP beta genes, these regulatory sequences may be involved in the in vivo activation of these genes by hyperthermia.

The heat shock genes in the Drosophila montium subgroup: chromosomal localization and evolutionary implications

Thehsp70, hsp83, hsrω, and thesmall heat shock protein genes were mapped on the polytene chromosomes of six species, representative of the geographical distribution of theDrosophila montium subgroup of themelanogaster species group. In addition, based on hybridization conditions, the putative locus of thehsp68 gene is given. In contrast to the situation in themelanogaster subgroup species, thehsp70 locus is single in themontium species. Thehsp83, hsrω and thesmall hsp loci are also single in themontium genomes studied here, a common feature of allDrosophila species. Among thehsp genes studied, thesmall hsp genes and thehsrω-homologous sequences exhibit a higher degree of divergence between themelanogaster and themontium subgroups. Our results support the idea that themontium subgroup species has a genome organization closer to that of the common ancestor compared with themelanogaster subgroup species.

The Heat-Shock Gene hsp83 of Drosophila auraria: Genomic Organization, Nucleotide Sequence, and Long Antiparallel Coupled ORFs (LAC ORFs)

Abstract. The genomic organization of the hsp83 gene of Drosophila auraria, a far-eastern endemic species belonging to the montium subgroup of the melanogaster species group, is presented here. Based on in situ hybridization on polytene chromosomes, cDNA and genomic clone mapping, nucleotide sequencing, and genomic Southern analysis, hsp83 is shown to be present as a single-copy gene at locus 64B on the 3L chromosome arm in D. auraria. This gene is organized into two exons separated by a 929-bp intron. The first exon represents the mRNA leader sequence and is not translated, while the coding region, having a length of 2,151 bp, is solely included in the second exon. Nucleotide sequence comparisons of D. auraria hsp83 with homologous sequences from other organisms show high conservation of the coding region (88–92% identity) in the genus Drosophila, in addition to the conserved genomic organization of two-exons–one-intron, of comparable size and arrangement. A phylogenetic tree based on the protein sequences of homologous genes from representative organisms is in accord with the accredited phylogenetic position of D. auraria. In the hsp83 gene region, a second case of long antiparallel coupled open reading frames (LAC ORFs) for this species was found. The antiparallel to the hsp83 gene ORF is 1,554 bases long, while the two ORFs overlap has a size of 1,548 bp. The anti-hsp83 ORF does not show significant homology to any known gene sequences. In addition, no similar LAC ORF structures were found in homologous gene regions of other organisms.