A study of karyotypes and heterochromatic associations in Artemia,with special reference to two N. Greek populations

The chromosomes of three stains of Artemia were studied, a bisexual diploid (A. franciscana, strain GSL), and two parthenogenetic tetraploids from Northern Greece. Routine karyotypes were constructed for the diploid and tetraploid forms, as well as a Giemsa C-banding karyotype of the bisexual form; some data are also presented on the chromosomal C-banding patterns of the parthenogenetic populations. The possible significance of various chromosomal configurations that have been observed, and their relationships to heterochromatin, are discussed.This paper is dedicated to Professor C. Barigozzi for introducing us to Artemia research.Supported by a grant from the Greek Ministry of Agriculture, Request offprints from: Th. Abatzopoulos, Lab. of General Biology, School of Sciences, Aristotelian University, Thessaloniki, 54006, Greece.     

A note on nonperiodic undamped oscillations,with special reference to brain waves

Nonperiodical sustained fluctuations of electrical potential are characteristic of the rhythms of cortical electric activities. A nonperiodical negatively or positively damped oscillation would be a general solution of any first order linear system of differential equations. Attention is called to a somewhat specialized type of a system of ordinary linear differential equations, which are used by Vito Volterra (Leçons Sur la Théorie Mathématique de la Lutte Pour la Vie, Paris, Gauthier-Villars, 1931) in his theory of interdevouring species. This system of linear equations leads to nonperiodicalundamped oscillations and admits several plausible interpretations in terms of possible biophysical reactions in the brain. A number of new problems is posed and discussed by this study.     

A molecular phylogeny of the genus Lygodium (Schizaeaceae) with special reference to the biological control and host range testing of Lygodium microphyllum

Lygodium microphyllum, first naturalized in the 1960s, has aggressively invaded forest-dominated wetlands in southern and central Florida. The indeterminate growth of this invasive climbing fern creates thick rachis mats which climb over shrubs and trees smothering the underlying growth and carrying ground fires into the forest canopy. Foreign surveys for natural enemies identified 20 species of insects and two species of mites. Host range testing of three insect species and one mite included five Lygodium species (L. palmatum, L. volubile, L. cubense, L. venustum, and L. oligostachyum) native to the United States and the West Indies. A molecular phylogeny of the genus was conducted using the trnL intron and the trnL-F intergenic spacer of chloroplast DNA to determine the relationship of L. microphyllum to other Lygodium species. Three major clades appeared, one with L. palmatum and L. articulatum (the most basal), a second with L. reticulatum and L. microphyllum, and a third comprising the other species examined. Lygodium microphyllum appeared at the end of a long branch approximately equidistant from all species of interest preventing the correlation of genetic distance and host range behavior. However, inspection of the results of host range experiments showed a relationship between the presence of a related biotype or species of the insect on a related alternate host and the ability of that insect to develop on that alternate host. Ancestral host usage and ecological fitting are examined as possible explanations for the acceptance of L. palmatum by the tested musotimine insects.     

Karyotypic study of four gibbon forms provisionally considered as subspecies of Hylobates (Nomascus) concolor (Primates, Hylobatidae)

We report here a karyotypic study of 6 individuals of Hylobates concolor leucogenys, 2H, concolor siki, 3H, concolor gabriellae, 1 hybrid H, concolor leucogenys x H. concolor ski, 3 hybrid H. concolor gabriellae x H. concolor siki and 2 hybrid H. concolor hainanus x H. concolor leucogenys. Difficulties raised by the morphological identification of subspecies are discussed, and a new morphological characteristic for recognising female H. concolor gabriellae is described. Each of the 4 subspecies appears to be distinguishable on the basis of its karyotype: H. concolor leucogenys differs from H. concolor siki by a reciprocal translocation, from H. concolor hainanus by a pericentric inversion and from H. concolor gabriellae by the presence of both of these two rearrangements. However, these data do not allows us to identify a phylogenetic relationship between the subspecies because, with respect to the karyotypes, none occupies an ancestral position in comparison with the others.     

Milk composition of captive vervet monkey (Chlorocebus pygerythrus) and rhesus macaque (Macaca mulatta) with observations on gorilla (Gorilla gorilla gorilla) and white handed gibbon (Hylobates lar)

The nutrient content and fatty acid composition of vervet monkey milk has been determined and is compared with rhesus macaque, and two hominoid apes, the white handed gibbon and gorilla. With 15.7 ± 4.1 g protein, 33.1 ± 9.4 g fat, and 85.1 ± 7.5 g lactose per kg milk, vervet monkey milk does not differ from that of rhesus macaque, and is within the range of other primates. Small amounts (> 1 g kg^− 1) of oligosaccharides, glucose, galactose and fucose were noted. In comparison, gorilla milk has a low fat content of 13.8 g kg^− 1, but contains high levels of oligosaccharides at 7.0 g kg^− 1 milk. The hominoid partner, the white handed gibbon, contains no oligosaccharides and a milk fat content similar to other hominoid species. Differences between vervet monkey and rhesus macaque milks were observed in the electrophoretic pattern of the milk proteins, mainly amongst the κ- and γ-caseins, which also differ from that of the hominids. The fatty acid contents of these milks differ from studies where a natural diet of leafy material was available in that a low content of α-linolenic acid (18:3n−3) was noted. A phylogenetic effect is observed for the content of 8:0, 10:0 fatty acids between the Cercopithecidae and Hominoidea, and a further phylogenetic effect suggested between the Hylobatidae and Hominidae.     

Monandrous social organization of pigtailed langurs ( Simias concolor ) in the Pagai Islands, Indonesia

Between June 1986 and October 1992, in 3 periods totaling 12 months, we studied social organization of pigtailed langurs (Simias concolor)in the Pagai Islands, Indonesia. With one possible exception, all of 20 family groups contained only 1 adult male each. Nine of them contained only 1 adult female,and 11 contained ≥2 adult females. Mean group size is 4.1 individuals. Home ranges varied from 7 to 20 ha, and population density averages 21 animals/km ² . Simias concoloris sexually dimorphic⤖n a museum sample males average 29% heavier than females, and their canine teeth are on average nearly twice the length of female canines. Combined data from several studies indicate that 60% of S. concolorgroups contain an adult pair plus young,and 40% are multifemale groupings. We sggest that any 1-male mating system that comprises a mixture of 1-female and multifemale groups in the same population should be termed monandry.     

Studies on gut pigment in skin-parasitic monogeneans, with special reference to the monocotylid Dendromonocotyle kuhlii

Adults and immature specimens of the monocotylid, monogenean parasite Dendromonocotyle kuhlii contain brown gut pigment and are found on the upper skin of the stingray Amphotistius kuhlii. No indication was found that the living parasites had been feeding on blood. Tests showed that the gut pigment of the parasites is not haematin. The upper epidermis of the stingray contains pigment cells, possibly of two kinds. Although the evidence is not conclusive, it seems likely that the gut pigment of the parasite is derived from host skin pigment ingested when the parasite browses on the fish's skin. Observations on Entobdella australis, from the same host and from Taeniura lymma, support this view. The microbothriid skin parasite Pseudoleptobothrium aptychotremae also contains gut pigment which is not haematin and may be derived from pigment in the skin of its host, Aptychotrema banks.

Experimental evidence is given in support of earlier observations that Entobdella soleae does not damage host dermis during feeding.     

A note on the use of cross-linked starch in microbiology with special reference to detecting amylase production

Anilogel-E, a cross-linked starch, can be used with distinct advantages where native starch or soluble starch are conventionally used, e.g. in scoring for amylolytic organisms, as an ingredient of fermentation media, and in enhancing protoplast regeneration. It is particularly useful for the direct visualization of amylase producing micro-organisms on solid media, making prior replication of colonies unnecessary.     

A note on the use of cross-linked starch in microbiology with special reference to detecting amylase production

Anilogel-E, a cross-linked starch, can be used with distinct advantages where native starch or soluble starch are conventionally used, e.g. in scoring for amylolytic organisms, as an ingredient of fermentation media, and in enhancing protoplast regeneration. It is particularly useful for the direct visualization of amylase producing micro-organisms on solid media, making prior replication of colonies unnecessary.     

Trends in the evolution of dicotyledonous seeds based on character associations, with special reference to pachychalazy and recalcitrance

VON TEICHMAN, I. & VAN WYK, A. E., 1991. Trends in the evolution of dicotyledonous seeds based on character associations, with special reference to pachychalazy and recalcitrance. The possible evolutionary status of the endothelium, hypostase, pachychalaza and the recalcitrant viability behaviour of seeds is considered in relation to bitegmy/unitegmy, crassinucellate/tenuinucellate ovules, nuclear/cellular endosperm development, large/small seed size, woody/herbaceous habit and tropical/temperate habitat. The presence of the endothelium, hypostase, pachychalaza and recalcitrance in dicotyledonous families is plotted against Dahlgren's system of classification. Results are compared with Sporne's advancement index for the various families. An endothelium is considered derived since it occurs more often in highly evolved superorders and is significantly associated with derived ovule and endosperm character states as well as with smaller seed size. A hypostase appears to be relatively ancestral and is significantly associated with pachychalazy and recalcitrance. The endothelium and hypostase have developed independently in many taxa and could be interpreted as being structurally and functionally analogous. Pachychalazy and recalcitrance are significantly associated with ancestral ovule character states and, at the species level, with large seed size (overgrown seed), woody habit and tropical habitat. The presence of pachychalazy, recalcitrance and associated large seed size are therefore regarded as ancestral character states of the dicotyledons. Consideration of currently accepted dicta on seed character state polarity, suggests a reversal in the evolutionary status of pachychalazy and large seed size.     

Some aspects of the host plant relations of the chrysomelid genus Haltica with special reference to Haltica lythri

The oligophagous chrysomelid Haltica lythri Aubé is a member of a taxonomically difficult genus. Species are morphologically very similar and knowledge of the food plant often facilitates correct identification. The relationship of H. lythri to its natural host plant Epilobium hirsutum L. and several potential hosts is compared with respect to adult and larval feeding preference, larval feeding behaviour, oviposition behaviour, development and adult survival. The order of preference suggested by feeding tests was generally similar to that suggested by other criteria. Leaf pubescence may be important in the oviposition preference of Haltica lythri and Haltica palustris Weise. The observations are discussed in relation to the ecology of these beetles.

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Résumé Le chrysomélide Haltica lythri Aubé, appartient à un genre difficile sur le plan de la taxonomie. Les espèces de ce genre sont en effet morphologiquement très semblables et souvent leur identification est facilitée par la connaissance de leur plante-hôte. Les relations de H. lythri à l'égard de son hôte naturel Epilobium hirsutum et de plusieurs hôtes potentiels sont comparées par référence: au preferendum alimentaire de la larve et de l'adulte, au comportement alimentaire de la larve, au comportement de ponte, au développement et à la survie de l'adulte. L'ordre de préférence suggéré par les tests d'alimentation est en général identique à celui obtenu sur la base d'autres critères. La pubescence des feuilles peut jouer un rôle important dans l'oviposition de Haltica lythri et H. palustris. Les observations faites sont discutées en rapport avec l'écologie de ces insectes.

     

Fungal associations of Danish Calluna vulgaris roots with special reference to ericoid mycorrhiza

Fungi were isolated from young, serial-washed roots of Calluna sampled from a Danish heathland, Hjelm Hede. Of the 626 isolates, those that were dark, sterile and septate were divided into 13 morphological groups based on their appearance in culture on malt agar. Mycorrhizal synthesis in vitro showed that several groups formed typical ericoid mycorrhiza with seedlings of Calluna; these ericoid mycorrhizal fungi were morphologically similar to Hymenoscyphus ericae. The identities of the other dark, septate fungi are uncertain. Oidiodendron spp. were isolated in a very low frequency; these fungi also formed typical ericoid mycorrhiza. The Calluna root system on Hjelm Hede demonstrated a high morphological diversity among the associated dark, septate fungi suggesting that more than one fungus could coexist in the same host root system.     

Three species of Heilipodus (Coleoptera,Curculionidae) with different karyotypes and sex chromosome systems

This work includes the cytological studies of three species of Heilipodus (Coleoptera, Curculionidae, Molytinae, Hylobiini) that live on plants of the genus Eryngium (Umbelliferae). The three have the same chromosome number (2n=30), but differ in the morphology of their autosomes and in their sex chromosomes.All specimens of Heilipodus erythropus (Klug) showed a typical parachute-like sex bivalent, some individuals of Heilipodus sp. possessed either a simple Xy_p or a sex multivalent involving a telocentric autosomal pair and the parachute bivalent. Finally, Heilipodus scabripennis (Klug) has multiple sex chromosomes neoX_pneoX-neoYy_p.     

Patterns of chromosome banding in four nabid species (Heteroptera, Cimicomorpha, Nabidae) with high chromosome number karyotypes

Male Nabis (Aspilaspis) indicus (St?l), N. (A.) viridulus Spinola, Himacerus (Himacerus) mirmicoides (O. Costa) (2n=32+XY) and Prostemma guttula (Fabricius) (2n=26+XY) were studied using C-banding, silver nitrate staining and base-specific fluorochrome (DAPI and CMA(3)) staining. N. indicus differed from N. viridulus in distribution pattern of C-bands, which were telomeric in the former while interstitial in the latter. H. mirmicoides showed interstitial C-bands in the majority of autosomes. P. guttula had no conspicuous C-bands in other chromosomes, but only in the Y, which was totally heterochromatic. C-heterochromatin was labelled with DAPI, indicating that it was AT-rich. In every species, both X and Y chromosomes were NOR-bearing, and the NOR regions were GC-rich. In H.mirmicoides and P. guttula, NORs showed sub-median location in the X and distal in the Y, such a pattern being probably common in Nabidae. The present paper provides new information on the genome organization and new cytological markers useful for a better insight into karyotype evolution of nabid species.     

A review of chromosome cytology in Hyacinthaceae subfamily Ornithogaloideae (Albuca, Dipcadi, Ornithogalum and Pseudogaltonia) in sub-Saharan Africa

The chromosome cytology of Hyacinthaceae subfamily Ornithogaloideae is reviewed within the framework of a recent molecular-based classification, with particular emphasis on its center of diversity in sub-Saharan Africa. We also provide new chromosome counts for sections that are unknown or poorly known cytologically. Albuca subgen. Namibiogalum (9 spp.) probably has an ancestral base number of x = 10 but subgen. Albuca (± 70 spp), subgen. Monarchos (9 spp.) and subgen. Osmyne (36 spp.) have x = 9. The pattern in subgen. Urophyllon (3 spp.) is remarkable: although x = 6 is likely, the species in the section exhibit a range of 2n = 12, 10, 8, 6 and 4 (exclusive of polyploidy). All karyotypes have three large chromosome pairs and a variable number of small chromosomes. Pseudogaltonia (2 spp.) has x = 9 and Dipcadi (26 spp.) possibly x = 9 in series Uropetalum and x = 6 in series Dipcadi, which exhibits a pattern of descending dysploidy leading to n = 3 in D. marlothii. In Ornithogalum (± 130 spp.) chromosome numbers are known for only 24 of the ± 84 sub-Saharan species, mostly from subgen. Aspasia and subgen. Ornithogalum sect. Linaspasia, both of which have x = 6, and from subgen. Galtonia, which has x = 8. In contrast, x = 7 is basic for the Eurasian sects. Honorius and Melophis, and x = 18 seems likely for sect. Cathissa. Sect. Ornithogalum, the cytology of which we does not examine in detail, may have x = 9. Polyploidy is apparently rare in the sub-Saharan African ornithogaloids, in marked contrast to the high frequency of polyploidy among Eurasian species. In Albuca just 3 or possibly 4 sub-Saharan species (9% or 13% of those counted) are exclusively polyploid and 5 more have diploid and polyploid races; and in sub-Saharan Ornithogalum, only the tropical O. gracillimum is exclusively polyploid, and the western southern African O. hispidum has diploid and polyploid races.     

Maternal age-specific rates of numerical chromosome abnormalities with special reference to trisomy

Summary The effect of maternal age on the incidence of chromosomally normal spontaneous abortion and different categories of chromosome abnormality among all clinically recognized human pregnancies was evaluated. The results provide no evidence for a significant association of age with sex chromosome monosomy or polyploidy, but clearly demonstrate an effect of age on the frequency of trisomy and chromosomally normal spontaneous abortions. Estimated maternal age-specific rates of trisomy among all recognized pregnancies were calculated and suggest that a majority of oocytes of women aged 40 years and older may be aneuploid.