ISSN:0947-5745    

DOI:10.1111/j.1439-0469.1991.tb00455.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractSpecies of the oligochaete genusEnchytraeus aremorphologically rather similar; they are difficult to distinguish or even inseparable on conventional light microscopic methods. In individuals from 19 populations of different origin and in some cases unknown species identity the ultra‐structure of mature spermatozoa was investigated. Their morphometric and qualitative data were used as morphological taxonomic characters. With the exception of a genetically polymorphic field population of E. albidussc>, the material investigated came from genetically monomorphic laboratory inbred strains. The structure of the thread‐like spermatozoa generally conforms with the sperm type known for the family. Numerical characters used were 1. length of the acrosome, 2. length of the corkscrew‐like nucleus, 3. number of helical spires of the nuclear flange, 4. periodicity of the flange spires proximally and distally, 5. angle of the flange to the longitudinal axis of the nucleus, 6. length of the midpiece, 7. number of mitochondrial helical spires, and 8. length of the flagellum. Besides the shape of the nucleus, the complex structure of the acrosome provides further specific qualitative differences such as, length ratio of primary acrosome vesicle to the entire acrosome, extension of a subdistal electron‐dense material, and absence or presence of specific structures underneath the primary acrosome vesicle.Eight populations show highly significant differences from each other and from the remaining populations on the basis of morpnometric data alone. In addition, these populations ‐ recognizable as different species on conventional methods ‐ can also be discriminated by qualitative differences of their spermatozoa. The spermatozoa of 10 other populations appear to be highly similar due to the length of their nuclei. Number of nuclear spires, length of acrosome, flange spire periodicity and especially structural details of the acrosome, however, separate these 10 populations into two significantly different groups, one with six species and the other with four. The group of four, which has also been found in parallel, independently conducted non‐morphological investigations, are considered to belong to one species. Certain morphological data divide the group of six into two groups of three, which is also supported by non‐morphological methods and crossbreeding experiments ‐ both groups are distinct species.Statistical comparisons generally show no or only slight variability of morphometric data for sperm of one individual. The variability between individuals of the genetically monomorphic laboratory cultures is higher but in no case does it prevent species identification. The greatest intraspecific variation has been observed in theE. albidusfield population: spermatozoa of individuals differing in the pattern of single enzymes deviate significantly in their morphometric data, and on the basis of these morphometric data alone they are inseparable from spermatozoa of certain other species. However, qualitative characters are not affected and species can easily be discriminated on the basis of acrosomal structures.The present example of a comparison of spermatozoa demonstrates the possibilities and importance of ultrastructural analysis as an advanced morphological method for solving taxonomical problems at

ISSN:0947-5745    

DOI:10.1111/j.1439-0469.1991.tb00456.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractTwenty one laboratory populations of the genusEnchytraeus, belonging to an unknown number of species, were investigated for 20 isozymes and unspecific protein patterns. Single specimens were used for sample preparation. The separation of proteins was performed in polyacrylamid gels by isoelectric focusing (IEF). 11 populations could be clearly differentiated from all others by their isozymes. The other 10 populations form three groups, two with each three populations and one with four. Within these groups the populations yielded identical isozyme patterns with respect to all enzymes studied. The two three‐population‐groups differed from each other only in three out of the 20 enzyme systems, while some of the other populations showed patterns of their own for all enzymes and therefore can be identified by any of them. The degree of genetic similarity between the investigated populations obviously differs considerably. Furthermore, this means that not all enzymes are suited for differentiation to the same extent, some of them have more discriminating power than others. Concerning the differentiability of the populations, the general protein patterns led to the same results as isozymes. Therefore, the protein patterns can be used as diagnostic characters, which allow identification of single specimens. Crossbreeding experiments proved the species status of all differentiable populations. The lack of any polymorphism within the laboratory populations facilitated the investigations. However, it seems not very likely that polymorphism, possibly occurring in field populations, would substantially limit the suitability of isozymes or general protein patterns as diagnostic charact

ISSN:0947-5745    

DOI:10.1111/j.1439-0469.1991.tb00457.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractSpecies identification in the Enchytraeidae is extremely difficult as in many groups of lower invertebrates. Clear‐cut morphological character differences which would allow an unambiguous delimitation are almost totally lacking between numerous species. Consequently, their identification and their phylogenetic relationships cannot be discerned by classical morphological methods alone. We show in this study that comparative analysis of DNA fragment variation found by restriction endonuclease digestions provide a suitable means for both species identification and analysis of their phylogenetic relationships.We have studied fragment length variation of ubiquitin and 18S rRNA genes in ten different populations of the genusEnchytraeus.Two populations which belong to the two speciesE. albidusandE. fragmentosuscan be clearly identified by their restriction fragment patterns. The remaining eight populations are grouped into four clusters. The fragment patterns are identical within each group but differ considerably between these groups. Since the differences between these groups and between the two well characterized species are in the same range, it is suggested that these four groups may represent four differentEnchytraeus‐species.Phylogenetic analysis using Wagner maximum parsimony reveals a clearly defined pattern of relationships of the species stud

ISSN:0947-5745    

DOI:10.1111/j.1439-0469.1991.tb00458.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractThe composition of lipids from severalEnchytraeus(Annelida, Oligochaeta) andTisbe(Arthropoda, Crustacea) populations or species, respectively, has been investigated using chromatographic and spectrometric methods. Triglycerides and polar components were found to be the predominant components. In both genera, the fatty acid moiety of the triglycerides consisted mainly of saturated and unsaturated C14‐, C16‐ and C18‐compounds; particularly, inTisbepopulations additionally branched constituents were present. Predominantly fatty acids inTisbepopulations were C16‐compounds whereas C14‐compounds were major constituents inEnchytraeusindicating a differently oriented synthetase activity in these groups. The analysis of the fatty acid profiles and the phospholipid patterns revealed distinct groups within theEnchytraeuspopulations which can be discriminated by a different balance of ß‐oxidation and desaturase systems. These findings are discussed in context with the fatty acid metabolism in these organisms considering the results obtained with other methods and evaluating the applicability of lipid analysis in these organisms for chemosystematic in

ISSN:0947-5745    

DOI:10.1111/j.1439-0469.1991.tb00459.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractThe efficiency of crossed immunoelectrophoresis (CIE) for the determination of taxonomic relationships between populations of two different selected animal groups has been investigated employing eight populations of the family Tisbidae and eleven populations of the family Enchy‐traeidae grown under laboratory conditions. Antisera were raised in rabbits against extracts from twoTisbeand threeEnchytraeuspopulations. The antisera were used in CIE in homologous and heterologous combination with antigens of each population of the two groups. Numbers of heterologous immunoprecipitates were counted and divided by the numbers of the corresponding homologous combination. A decrease in the resulting values (matching coefficients) represents a decrease in the degree of relationship between the populations.The relationship patterns resulting from the CIE analysis showed within the genusTisbetwo pairs of closely related populations:T. holothuriae/T. battagliaiandT. gracilis/T. cucumariae. T. bulbisetosaandT. furcataclearly were different species but the position of these species within the genusTisbecould not exactly be determined.Within the genusEnchytraeustwo groups of very closely related populations could be distinguished: (1.) E, F, and G; (2.) C and A. These two groups form a larger group of six closely related populations including also population D. The speciesE. albidus, E. bigeminusandE. frag‐mentosustogether form another group which is more distant to these six populations. The populations J and B are even more remote from t

ISSN:0947-5745    

DOI:10.1111/j.1439-0469.1991.tb00460.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractSince the analysis of phylogenetic relationship in the taxonTisbe(Copepoda, Harpacticoida) by using morphological methods often leads to controversial results we have tested a molecular approach as an alternative. The restriction site variation in four species ofTisbeand inArtemia salinawhich was used as an outgroup was analyzed. Eleven different restriction enzymes were used and six different genes (ribosomal, actin‐, histone‐, ubiquitin‐,α‐andβ‐tubulin genes) were tested using heterologous hybridization probes in search of suitable differences which allow a clear identification of the species and which are useful for a phylogenetic analysis. The best results were obtained with 18S rRNA gene sequences which were amplified in vitro by the polymerase chain reaction technique prior to restriction enzyme analysis. The in vitro amplification solved the problems which were encountered with the other analyses due to the relatively small amounts of highly purified DNA which could be isolated from the cultured animals. Every species can be recognized by a typical restriction fragment pattern. No intraspecific variation could be detected in the conserved gene sequences tested. However, even the highly conserved 18SrDNA sequences exhibit sufficient interspecific variation for a phylogenetic analysis. A phylogenetic tree was inferred from the data with a computer program using the Wagner maximum parsimony method. It is discussed that the presented analysis technique can presumably be scaled down to the level of a si

ISSN:0947-5745    

DOI:10.1111/j.1439-0469.1991.tb00461.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractEight taxa of the genusTisbe, with up to 28 laboratory populations, were analysed at four polymorphic loci (phosphoglucose isomerase, phosphoglucomutase‐1, arginine phosphokinase‐1 and ‐2), by means of vertical polyacrylamide eel electrophoresis. ‐ Despite high intraspecific variability, and partly interspecific identity of alleles (electromorphs), the majority of the studied taxa could clearly be discriminated by at least one diagnostic locus (Nei'S genetic identity I=0) in paired comparisons. Relatively greatest discriminative power was demonstrated in arginine phosphokinase (APK‐1), with 19 species pairs being differentiated, accepting probability ≥ 99 % correct diagnosis. Nevertheless, in the highly variable phosphoglucomutase (PGM‐1) 14 pairs proved to be distinguishable. Including level of probability ≥99%, only one species pair (T. holothuriaeVenice ‐T. battagliai) could not be differentiated by any of the loci examined; hence, they must be considered as the most allied of all taxa studied. ‐ Means of genetic distance indicated different levels of divergence in the taxa, and might reflect stages in speciation process. Compared to means of genetic identity within local populations (I=0.86‐1.00), the similarity betweenT holothuriaeVenice andT. battagliai(I = 0.78) was found to be characteristic rather of the sub‐ or semispecies level according to AYALA (1975). Genetic affinities within three pairsT. holothuriaeVenice ‐T. holothuriaeHelgoland (I = 0.53),T. cucumariae ‐ T. gracilis(I = 0.56), andT. bulbisetosa ‐ T. furcata(I = 0.56), fell into the range generally covered by sibling species. The majority of the remaining taxa was well separated at the (non‐sibling) species level indicated by genetic identities I ≤ 0.34. ‐ According to the phenetic tree based on identity coefficients (UPGMA), three sets of taxa could be differentiated with their respective members probably exhibiting closer genetic interrelations: (a)T. holothuriae(Helgoland) ‐T. holothuriae(Venice) ‐T. battagliai, (b)T. bulbisetosa ‐ T. furcata ‐ T.

ISSN:0947-5745    

DOI:10.1111/j.1439-0469.1991.tb00462.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractTisbe furcata(Baird, 1837) is redescribed in particular detail from a laboratory stock raised from individuals collected from the rocky intertidal of Helgoland (North Sea). This detailed description has revealed the following new characters: labrum rectangular caudally with about 20 dentiform spinules; mandibular exopodite with two aesthetasc‐like bluntshaped setae, its endopodite with three groups of three setae each which are confluent at their bases, segment III P 1 endopodite with an outer spinule row on anterior face (instead of a spine‐like seta) and a tube‐pore subterminally; P2‐4 endopodite and exopodite inner setae ringed in distal portion; inner two setae of P 5 baseoendopodite with common base; terminal seta of male P 5 spiniform with a weakly chitinized distal third and a terminal spinule. A phylogenetic evaluation confirms theT. holotburiae‐groupandT. gracilis‐sroupof species defined by Volkmann‐Rocco(1973 a and 1972 b respecively) and revealsT. furcataas belonging to the sister‐group of these latter two groups together. A new group, theT. furcata‐groupof species, is proposed comprising the following species:T, furcata, T. celata, T. variana, T. ianthina, T. carolinensis, T. bocqueti, T. lagunari

ISSN:0947-5745    

DOI:10.1111/j.1439-0469.1991.tb00463.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractAll six naupliar stages of six species ofTisbeLilljeborg, 1853 are compared:Tisbe gracilis(T. Scott, 1895),T. cucumariaeHumes, 1957,T. furcata(Baird, 1837),T. bulbisetosaVolkmann‐Rocco, 1972,T. bolothuriaeHumes, 1957 andT. battagliaiVolkmann‐Rocco, 1972. The nauplii ofT. cucumariaeare described and differences to those of the other species are specified. The appendages of only nauplius VI are figured.T. bolothuriaeandT. battagliai irecharacterized by the reduction of oral structures. A cladogram depicting relationships withinTisbeis deduced from a comparison and evaluation of these naupliar characters. The cladogram supports some previous findings, viz. the close relationship ofT. bolothuriaeandT. battagliaias well as ofT gracilisandT. cucumariaebut deviates in other respects from the cladogram deduced by Dahmset al. (1991, this volume) from adult characters. The discrepancies are discus

ISSN:0947-5745    

DOI:10.1111/j.1439-0469.1991.tb00464.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY