New observations onMonotosporella rhizoidea

Monotosporella rhizoidea is described, and illustrated with ligh and scanning electron micrographs, from submerged wood in Hong Kong. Our collection differs from the protologue, in having smaller conidia and longer condidiophores. The formation of multiple lobes which swell downwards over the conidiophore or existing conidiogenous cells is an unusual feature inMonotosporella. A synopsis and a key, as well as diagrammatic representations of the species ofMonotosporella are provided.     

Serjania lancistipula (Sapindaceae), a new species from Bahia,Brazil

A new species ofSerjania (S.lancistipula) from Bahia belonging to theS. paradoxa group is described and illustrated. A key to the species in theparadoxa group is provided.     

A new species of Tachia (Gentianaceae) from Suriname

A new species ofTachia,T. longipes, is described and illustrated. It is distinct from the other species ofTachia not only in its leaf and stem morphology but also in its characteristic pollen. A revised key to the neotropical species ofTachia is also provided. Studies for theFlora of the Guianas. No. 87.     

Evolution of thedec-1 eggshell locus inDrosophila. I. Restriction site mapping and limited sequence comparison in themelanogaster species subgroup

Summary We have analyzed 18 kb of DNA in and upstream of thedefective chorion-1 (dec-1) locus of the eight known species of themelanogaster species subgroup ofDrosophila. The restriction maps ofD. simulans, D. mauritiana, D. sechellia, D. erecta, andD. orena are shown to have basically the restriction map ofD. melanogaster, whereas the maps ofD. teissieri andD. yakuba were more difficult to align. However, the basic amount of DNA and sequence arrangement appear to have been conserved in these species. A small deletion of varying length (65–200 bp) is found in a repeated sequence of the central transcribed region ofD. melanogaster, D. simulans, andD. erecta. Restriction site mapping indicated that thedec-1 gene is highly conserved in themelanogaster species subgroup. However, sequence comparison revealed that the amount of nucleotide and amino acid substitution in the repeated region is much larger than in the 5 translated region. The 5 flanking region showed noticeable restriction site polymorphisms between species. Based on calculations from the restriction maps a dendrogram was derived that supports earlier published phylogenetic relationships within themelanogaster species subgroup except that theerecta-orena pair is placed closer to themelanogaster complex than toD. teissieri andD. yakuba.     

Distribution and evolution of mobile elements in the virilis species group of Drosophila

The distributions of Penelope and Ulysses, two transposable elements that can induce hybrid dysgenesis, were studied in several species groups of Drosophila. No significant hybridization to Penelope and Ulysses probes was detected by Southern blot analyses of species outside the virilis group. In contrast, both element families have had a long residence in all species of the virilis species group, as indicated by their strong presence in the heterochromatic chromocenter. Except for D. kanekoi, D. lummei, and some strains of D. virilis, species of the group carry full-sized, and at least potentially functional, copies of both element families. Consistent with the occurrence of recent transposition, Penelope and Ulysses elements are located at different chromosomal sites in different geographical strains of the same species. A total of 79 Penelope and 47 Ulysses euchromatic insertion sites were localized to chromosomal subsections in species of the virilis group. Highly significant deviations from independence of the distributions of Penelope and Ulysses and previously established inversion breakpoints were documented, suggesting that these transposable elements may have played an important role in genomic reorganization and evolution of the virilis species group, which is especially rich in karyotypic variation. Received: 13 April 1999; in revised form: 20 July 1999 / Accepted: 27 July 1999     

Asolcus bennisi n. sp. (Hymenoptera,Proctotrupoidea) parasite oophage deGraphosoma lineata L. (Het. Pentatomidae)

Summary The Author describes from Morocco a new species ofAsolcus which is closely related to the sibling speciesA. basalis Wollaston andA. nigribasalis Voegelé. The species is namedA. bennisi and parasitizes in nature the eggs ofGraphosoma lineata L. The separation ofA. bennisi from the species of thebasalis group is based on biological tests and on a characteristic pigmentation of the parasitized host eggs reared under optimal laboratory conditions.      

Evolution and systematic relationships in theTriticeae (Poaceae)

The evolution and taxonomic relationships in theTriticeae are discussed with the view to highlight aspects of this agronomically important group of plants, which may be of interest to molecular biology. Some of these aspects are addressed in more detail in adjoining papers in which specific genomic loci have been examined at the DNA sequence or isozyme level. Aspects discussed include the systematics and geographic distribution of theTriticeae species, isozyme and chromosome pairing studies on some of the species as well as more recent developments in DNA analyses. A survey of the systematics of theTriticeae indicated that the genomic system ofLöve is probably the most useful starting point for interpreting molecular data even though the system has many problems from a taxonomic point of view. The geographical distribution ofTriticeae species, using both published and unpublished data, suggested that information of this type taken together with the theory of continental drift provides a broad time-span for considering data from DNA sequence studies. The significance, and modes of analyses, of isozyme studies were assessed because they often provide valuable characters in determining relationships between species. The main character underlyingLöve's andDewey's analyses of theTriticeae, namely chromosome pairing, is discussed with particular reference to isozyme studies to show that in some cases, such as species ofHordeum sensu lato, consistent relationships are obtained. Finally, new developments in understanding chromosome structure are considered in relation to the above variables in the taxonomy and evolution of theTriticeae.     

Flavonoid chemistry ofBlennospermatinae, a trans-Pacific disjunct subtribe ofSenecioneae (Asteraceae)

The flavonoid profiles of seven species ofAbrotanella and one species ofIschnea have been shown to be based upon kaempferol 3- and quercetin 3-O-glycosides and a delphinidin glycoside. Glucosides, glucuronides, arabinosides, diglucosides, and rutinosides of the flavonols were identified. The profile ofIschnea consisted solely of quercetin 3-O-glucoside and 3-O-arabinoside whereas the profiles of theAbrotanella species were more varied. Although infraspecific variation was not investigated in this study, the flavonoid chemistry of the two genera is in accordance with the flavonoid variation described for other members ofSenecioneae which are primarily flavonol producers. Based on the known phylogeny and biogeography, the flavonoid distribution from the perspective of long-distance dispersals across the Pacific is discussed. Such events should lead to genetic bottle-neck situations and depauperate flavonoid profiles. A summary of current flavonoid knowledge in theSenecioneae is supplied.     

Biochemical studies carried out on different groups ofCandida parapsilosis andCandida rhagii strains by comparing some cellular and mitochondrial activities

A comparative biochemical study was performed on some strains ofCandida rhagii and on strains belonging to different subgroups ofCandida parapsilosis. Measurements of alcohol dehydrogenase activity, resistance to drugs and occurrence of an alternative pathway enabled us to confirm the classification between several subgroups within theC. parapsilosis species.     

Cloning and characterization of thewhite andtopaz eye color genes from the sheep blowflylucilia cuprina

Summary Clones carrying thewhite andtopaz eye color genes have been isolated from genomic DNA libraries of the blowflyLucilia cuprina using cloned DNA from the homologouswhite andscarlet genes. respectively, ofDrosophila melanogaster as probes. On the basis of hybridization studies using adjacent restriction fragments, homologous fragments were found to be colinear between the genes from the two species. The nucleotide sequence of a short region of thewhite gene ofL. cuprina has been determined, and the homology to the corresponding region ofD. melanogaster is 72%; at the derived amino acid level the homology is greater (84%) due to a marked difference in codon usage between the species. A major difference in genome organization between the two species is that whereas the DNA encompassing theD. melanogaster genes is free of repeated sequences. that encompassing theirL. cuprina counterparts contains substantial amounts of repeated sequences. This suggests that the genome ofL. cuprina is organized on the short period interspersion pattern. Repeated sequence DNA elements, which appear generally to be short (less than 1 kb) and which vary in repetitive frequency in the genome from greater than 10⁴ copies to less than 10² copies, are found in at least two different locations in the clones carrying these genes. One type of repeat structure, found by sequencing, consists of tandemly repeating short sequences. Restriction site and restriction fragment length polymorphisms involving both thewhite andtopaz gene regions are found within and between populations ofL. cuprina.     

Die Zweiteiligkeit der Chromatophoren bei Cryptomonaden

In theChrysophyceae as well as in different species ofCryptomonas bilobed chromatophores are present. These chromatophores consist of two large parietal lobes closed to the lateral sides of the cell and joined by a narrow bridge on its dorsal part. A survey of all species with a single bilobed chromatophore is given. Besides, also species with two separate chromatophores have been found. The presence of several chromatophores inCryptomonas cells is doubtful. The morphology of the chromatophores has to be taken into consideration in the taxonomy ofCryptomonas.

     

MAX, a novel retrotransposon of the BEL-Pao family, is nested within the Bari1 cluster at the heterochromatic h39 region of chromosome 2 in Drosophila melanogaster

A homogeneous array of 80 tandem repeats of the Bari1 transposon is located in the pericentromeric h39 region of chromosome 2 of Drosophila melanogaster. Here, we report that the Bari1 cluster is interrupted by an 8556-bp insertion. DNA sequencing and database searches identified this insertion as a previously unannotated retrotransposon that we have named MAX. MAX possesses two ORFs; ORF1 putatively encodes a polyprotein comprising GAG and RT domains, while ORF2 could encode a 288-amino acid protein of unknown function. Alignment with the RT domains of known LTR retrotransposons shows that MAX belongs to the BEL-Pao family, which remarkable for its widespread presence in different taxa, including lower chordates. We have analyzed the distribution of MAX elements within representative species of the Sophophora subgroup and found that they are restricted to the species of the melanogaster complex, where they are heavily represented in the heterochromatin of all autosomes and on the Y chromosome.Communicated by G. P. Georgiev     

A NEW SPECIES OF NITELLA (CHARACEAE) BELONGING TO THE NITELLA FLEXILIS SPECIES GROUP IN NORTH AMERICA12

A new species of Nitella belonging to the N. flexilis species group is described. The neiu species shows definite relationships to N. flexilis, N. opaca, N. missouriensis, and N. mirabilis. Relationships of the new species to N. acuminata are also discussed.     

Discrepancy in divergence of the mitochondrial and nuclear genomes ofDrosophila teissieri andDrosophila yakuba

Summary Restriction sites were compared in the mitochondrial DNA (mtDNA) molecules from representatives of two closely related species of fruit flies: nine strains ofDrosophila teissieri and eight strains ofDrosophila yakuba. Nucleotide diversities amongD. teissieri strains and amongD. yakuba strains were 0.07% and 0.03%, respectively, and the nucleotide distance between the species was 0.22%. Also determined was the nucleotide sequence of a 2305-nucleotide pari (ntp) segment of the mtDNA molecule ofD. teissieri that contains the noncoding adenine+thymine (A+T)-rich region (1091 ntp) as well as the genes for the mitochondrial small-subunit rRNA, tRNA^f-met, tRNA^gln, and tRNA^ile, and portions of the ND2 and tRNA^val genes. This sequence differs from the corresponding segment of theD. yakuba mtDNA by base substitutions at 0.1% and 0.8% of the positions in the coding and noncoding regions, respectively. The higher divergence due to base substitutions in the A+T-rich region is accompanied by a greater number of insertions/deletions than in the coding regions. From alignment of theD. teissieri A+T-rich sequence with those ofD. yakuba andDrosophila virilis, it appears that the 40% of this sequence that lies adjacent to the tRNA^ile gene has been highly conserved. Divergence between the entireD. teissieri andD. yakuba mtDNA molecules, estimated from the sequences, was 0.3%; this value is close to the value (0.22%) obtained from the restriction analysis, but 10 times lower than the value estimated from published DNA hybridization results. From consideration of the relationships of mitochondrial nucleotide distance and allozyme genetic distance found among seven species of theDrosophila melanogaster subgroup, the mitochondrial nucleotide distance observed forD. teissieri andD. yakuba is anomalously low in relation to the nuclear genetic distance.     

The cladocera of a ditch at Tienhoven

Summary From 75-08-18 to 75-08-26, the Netherlands Hydrobiological Society investigated during a field research trip the influence of the dimensions of a ditch on its aquatic communities. With regard to theCladocera no direct relationship was found between the dimensions of the ditch and the occurrence of certain species ofCladocera. A decrease in the number of species ofCladocera was assessed in the narrowest part of the ditch.     

Floral anatomy and systematic position ofVivianiaceae

The floral anatomy of four species ofViviania has been studied. In the basic floral plan and essential floral anatomical featuresViviana closely resembles theGeraniaceae. Evidence from vegetative and floral anatomy, ultrastructural studies on phloem as well as phytochemistry supports geranialean affinity ofViviania; the placement within thePittosporales sensuHutchinson being unnatural.     

Molecular relationships between closely related strains and species of nematodes

Summary Electrophoretic comparisons have been made for 24 enzymes in theBergerac andBristol strains ofCaenorhabditis elegans and the related species,Caenorhabditis briggsae. No variation was detected between the two strains ofC. elegans. In contrast, the two species,C. elegans andC. briggsae exhibited electrophoretic differences in 22 of 24 enzymes. A consensus 5S rRNA sequence was determined forC. elegans and found to be identical to that fromC. briggsae. By analogy with other species with relatively well established fossil records it can be inferred that the time of divergence between the two nematode species is probably in the tens of millions of years.The limited anatomical evolution during a time period in which proteins undergo extensive changes supports the hypothesis that anatomical evolution is not dependent on overall protein changes.     

Three new species of Ocotea (Lauraceae) from southern Mexico

Three new species ofOcotea (O. disjuncta, O. iridescens, andO. rovirosae) from southern Mexico are described and illustrated.Ocotea disjuncta is related to theO. effusa group, whileO. iridescens seems to be related to theO. heydeana group. The relationships ofO. rovirosae are not clear.      

Phyletic and evolutionary relationships ofBrachyscome lineariloba (Compositae)

A comparison of karyotypes ofBrachyscome breviscapis (2n = 8),B. lineariloba cytodemes E (2n = 10), B (2n = 12) and C (2n = 16) suggests that these species have a homoelogous basic set of four chromosome pairs, two large pairs and two small, and that theB. lineariloba cytodemes E, B and C are related toB. breviscapis by successive additions of small chromosomes. A pronounced asynchrony of chromosome condensation between these large and small chromosomes has been observed. In the artificial hybrids betweenB. dichromosomatica (2n = 4) ×B. breviscapis, and theB. lineariloba cytodemes, theB. dichromosomatica chromosomes are similar in size and condensation behaviour to the small chromosomes ofB. breviscapis and ofB. lineariloba cytodemes E, B and C. Meiotic pairing in these hybrids also demonstrates the strong affinities between these chromosomes. It is suggested thatB. breviscapis may be of amphidiploid origin between a species with two large early condensing chromosome pairs and another,B. dichromosomatica-like species with two small late condensing pairs. It seems most likely that the additional small and late condensing chromosomes inB. lineariloba cytodemes E, B and C are derived from theB. dichromosomatica-like parent, and that each addition increases vigour, fecundity and drought tolerance, allowing these cytodemes to colonize more open and arid environments. Transmission of the univalents in the quasidiploidB. lineariloba cytodeme E was verified as being via the pollen, and not via the embryo sacs.The cytology ofBrachyscome lineariloba (Compositae, Asteroidae), 10.