Patterns of inversion polymorphism in three species of the Drosophila melanogaster species group

In Drosophila, chromosomal polymorphism due to paracentric inversions is very common and constitutes an adaptive character. The degree of chromosomal variability varies in different species and also in different populations of the same species. Chromosomal polymorphism in Indian natural populations of three species, D. melaonogaster, D. ananassae and D. bipectinata which belong to the melanogaster species group has been studied and the quantitative data on frequency of inversions have been reported. Behaviour of chromosome inversions has also been studied in laboratory conditions. The present review summarises the work done on inversion polymorphism in Indian populations of three species which clearly demonstrates that these three species vary in their patterns of inversion polymorphism and have evolved different mechanisms for adjustment to their environments although they belong to the same species group.     

Radioactive caesium in British mushrooms

Summary

Thirty-four different taxa of larger fungi have been analysed for their content of caesium 137 over a 3 year period. The majority of the material has been collected from various sites in Central Scotland; 38% of the collections were from North Wales and Merseyside. Comparison has been made between the same species from different sites and different species from the same site. It has also been possible to analyse the same species from the same plot on two consecutive years. The levels of caesium 137 in the fungal species analysed were extremely low when compared with their counterparts in Central Europe and it is concluded that the Chernobyl incident had little effect on the accumulation by these fungi of this radionuclide. There is no evidence that edible species accumulate caesium 137 at levels considered to be dangerous for consumption.     

Influence of temperature and humidity on the reproductive efficiency of Ixodes ricinus (Linnaeus, 1758) and Hyalomma marginatum Koch, 1844 (Ixodoidea, Ixodidae)]

Laboratory studies have been carried out on two species of ticks, I. ricinus and H. marginatum, showing different seasonal activity and different geographical distribution in nature. The purpose of the present study has been to investigate the effect of different combinations of temperature and humidity on the oviposition of I. ricinus and H. marginatum. An index of reproduction efficiency (no. eggs/wt female), established to relate the capacity of the females to produce eggs to their body weight, has been calculated; for I. ricinus 5 temperatures (18-20-25-27 and 30 degrees C) have been studied (Fig. 1), for H. marginatum 3 (25-30 and 32 degrees C) (Fig. 2) and for both species 2 R.H. (75-95%). An optimal range of temperature, within which the value of such an index doesn't change, has been demonstrated for both species by statistical testing (Table 1). A critical weight value as the minimum engorged female weight required for egg deposition has been identified with the weight of first female which has laid eggs. This weight, different in each species, is influenced by temperature and humidity.     

假丝酵母一新种——北京假丝酵母

本文研究了一株从水果表皮分离到的假丝酵母,它与至今已发表的所有已知假丝酵母均不相同,定名为北京假丝酵母(Candida beijingensis)。     

Biotyping of pathogenic cocci using mathematical methods

The differential information content of biological signs in the ecology of different staphylococcal and streptococcal species has been studied by the mathematical method. The method for the intraspecific differentiation of staphylococci, streptococci and gonococci into pathovars with the use of programs for the computerized analysis of the material has been proposed. The mathematical models of strain virulence in different coccal species are described.     

Regeneration potential of different wheat, rye and barley species in leaf explant culture

Regeneration potential of different wheat, rye and barley species in leaf explant culture. Comparative analysis of the induction ability of morphogenetic processes in vitro has been carried out in 16 wheat genotypes, 4 barley species and 6 rye genotypes. It has been shown that tetra- and hexaploid wheat species as well as wild barley species exhibited the highest embryogenic potential in the leaf explant culture while diploid wheat species and rye genotypes showed the lowest one. Genotypic dependence of processes of callus formation, induction of embryogenic calli and regeneration was revealed in the studied species.     

The proteins of the ejaculatory bulbs in different species of Drosophila

A comparative electrophoretic study or ejaculatory bulb proteins in 29 different Drosophila species has been carried out. In all analyzed species, ejaculatory bulb contains a major component (designated as PEB). It has molecular mass of 61-65 kDa in the species of virilis group, 33-36 kDa in species of obscura group, and 34-56 kDa in species of melanogaster group. Using immunoblotting technique, we have demonstrated that PEB is introduced into organs of female sex tract during mating. The nature and significance of revealed interspecific differences in PEB proteins has been discussed.     

NADPH-protochlorophyllide oxidoreductase: Reciprocal regulation in mono- and dicotyledonean plants

The influence of light on the expression of NADPH: protochlorophyllide oxidoreductase has been studied in different plant species. The presumptive precursors to this enzyme have been characterized by in vitro translation of poly (A) RNA and immunoprecipitation. Two bands of apparent molecular weights of about 42 000 and 44 000 have been found in light- and dark grown monocotyledonean species, whereas a single band has been observed preferentially in light grown species of dicotyledonean plants. Membrane proteins reacting with the antibody to protochlorophyllide oxidoreductase have been identified by the method of immune blotting. On the basis of these findings it is concluded that protochlorophyllide oxidoreductase proteins are present in the membranes of all illuminated plants for at least several days. The mode of regulation, however, has been found different in mono- and dicotyledonean plants.Abbreviations poly (A) polyadenylated - PBST buffer as described under Methods     

The innate immune response of finfish--a review of current knowledge

The decline in the fisheries of traditional marine species has been an incentive for the diversification of today's aquaculture sector into the intensive rearing of many finfish species. The increasing interest in commercial farming of different finfish species is expected to result in similar environmental and husbandry-related problems as have been experienced in the development of the salmonid farming industry. An understanding of the biology of the fish species being cultured, in particular the immune response is important for improved husbandry and health management of the species. The innate immune system of fish has generated increasing interest in recent years and is now thought to be of key importance in primary defence and in driving adaptive immunity. This review focuses on key components (cellular and humoral) of the innate immune responses of different fish species of commercial importance.     

Is a unified concept of species in ornithology possible? (An opinion of a practicing taxonomist)]

An analysis of current publications on species problem reveals the radical discrepancy between the statements of species reality in nature and different number of these "realities" in light of different species concepts. It has been shown, that the only realities are populations, and "species" is only logical construct--the notion. A concept of species is a system of interconnected notions, where the main element--ontology of species has been always given a priori to the real biodiversity. For that reason every concept of species creates its own "virtual reality". Various concepts of species are not mutually comparable, and can not be criticized from each other's views and from position of "reality". Biological and Phylogenetic Species Concepts competing in ornithology exclude each other completely, and the unified concept of species is principally impossible. But as generally accepted species "standard" is needed, the unified convention of species must take the place of the various concepts of species.     

Water Mites (Acariformes: Hydrachnidia) in a Mesotrophic Lake in Western Siberia

The taxonomic composition, biotopic distribution, and interannual dynamics of the population of water mites in Lake Kuchak (Western Siberia) have been studied. The occurrence has been analyzed. The dominant species in different biotops have been revealed. Forty-three species of water mites from 12 families are recorded. Acarofauna is primarily composed of eurybiontic species typical for stagnant waterbodies. The highest species diversity and a large number of mites are the most usual characteristics of shallow water areas with well-developed vegetation. The age structure has been shown to influence the distribution. It has been revealed that mature specimens seem to prefer life in shallow water, while specimens at the larval and nymphal stages tend to live at greater depths.     

The organization of ribosomal genes in vertebrates

The organization of the repeat unit of the ribosomal genes has been determined in 15 different species of vertebrates. The EcoRI and BamHI restriction maps of the rDNA from single individuals of different species of fishes, amphibians, and reptiles have been analysed. Two rDNA clones from Xenopus laevis (representing one complete repeat unit) were used as probes in Southern blots to detect restriction fragments containing ribosomal genes. The results obtained indicate that the transcribed regions are highly conserved in length and sequence inside the same zoological class. These regions are less conserved when species from different classes are compared but a general trend has been observed. In contrast, the length and sequence of the spacer regions are very variable, even within the same zoological class. Different types of heterogeneity have been observed; examples range from a single type of ribosomal repeat unit within a species to the absence of any detectable regular tandem array of units.     

The microflora in suppurative-catarrhal endometritis in cattle

Microflora isolated from cattle with acute postnatal pus-catarrhal endometritis has been studied. It is shown that the given pathology is caused by associations of different bacterial species. 284 strains isolated from the uterus content of 63 sick animals have been identified, their properties being studied. Pathogenic gram-negative bacilli and gram-positive pus-producing cocci are responsible for the studied pathology. Considerable inoculation capacity has been established for conditionally pathogenic microorganisms of different species and genera whose role in pathogenesis is to be found out.     

Peculiarities of the biotope distribution of click beetle larvae (Coleoptera, Elateridae) in the Irtysh River valley

The spatial distribution of Elateridae larvae in the Lower Irtysh valley has been analyzed. The larvae analyzed belonged to 19 Elateridae species inhabiting soils of the floodplain and the river terrace. It has been pointed out that the larvae of Paraphotistus nigricornis, Agriotes lineatus, Limonius parallelus, and Aplotarsus incanus are most tolerant to the regular spring flooding. It has been found that the species compositions of floodplains and terrace meadows are significantly different. As a rule, species with a wide tropical spectrum inhabit floodplain soils, including bush and forest habitats. At the same time, the terrace was dominated by species characteristic of open habitats, including the steppe zone. It has been revealed that the values of species diversity vary significantly in the floodplain and terrace plots, but the higher species richness (Menhinick index) was registered in the floodplain.     

Comparative histochemical studies of iron absorption in three fresh water teleosts.

Absorption of iron in the intestine of three different species of fishes, namely; Claris batrachus, Channa striatus and Esomus danricus has been described. These three species of fishes have different feeding habits, being omnivorus, carnivorus and herbivorus respectively. The absorption of iron has been studied at different time intervals; after three hours, six hours and nine hours. The mucosal epithelial cells, submucosal blood vessels and blood capilaries were the main site of iron absorption. A comparative account of absorption of iron of all three fishes is described and discussed.     

Morphogenesis of reconstructed enucleated Acetabularia cells

Survival and morphogenesis of the enucleated fragments of Acetabularia has been studied after their reconstruction from the cell membrane and the endoplasm. Membranes and endoplasms of different species as well as of the same species but from plants in different functional states and with different regenerative abilities were combined. It was shown that inability of plants for growth and morphogenesis was due to the membrane state. When reconstructing anuclear fragments from membranes and endoplasms of different species or the same species but from plants in different functional states, a phenomenon of membrane-endoplasm incompatibility was found.     

Features of moss mat structure and productivity in forest-bog complexes of West Siberia

The species composition and distribution of mosses over microrelief features on bogs have been assessed with various types of the water-mineral nutrient supply. The density of moss stalks in different moss species mats has been examined. Fraction analysis has been applied to weight and morphological characteristics of moss stalks. The contributions made by each fraction to the biomass production have been estimated. The linear and weight parameters of the photosynthesizing layer in mosses have been determined.     

Microevolutionary dynamics of a community of Drosophilids

The microevolutionary dynamics of a community of Drosophilids has been analysed in a western-Mediterranean locality (Bordils, NE of Spain) by comparing the daily and seasonal activities of the nine most abundant Drosophila species: D. subobscura , D. melanogaster , D. simulans , D. immigrans , D. phalerata , D. testacea , D. cameraria , D. hydei and D. picta collected during two periods widely distant in time. The resemblance between samples obtained in different months (seasonal component) has been determined and a clear-cut clustering of the collections according to the season is observed. A possible relationship between the environmental variables temperature and humidity, and the frequencies of the most abundant species in each seasonal cluster has been analysed by a correspondence analysis. This study allows to characterize each species according to its activity in definite intervals of temperature and humidity. Finally, daily and monthly activity patterns of the different species have been compared and found to be equivalent in the first and second periods. The results obtained allow the characterization of the species according to the environmental variables.     

Morphological and ultrastructural features in selected species of Licea (Myxomycetes)

Ultrastructural studies of selected species of Licea were made in order to elucidate relationships among species. Based on structural studies, species may be grouped as representing different stages of morphological complexity. The majority of species possess protoplasmodia and form sporangia. The two plasmodiocarpous species L. retiformis and L. variabilis possess more highly differentiated plasmodia and are an anomaly among Licea species. Processes along the margin of peridial lobes in several species of the genus are probably homologous with the capillitium in Listerella . The latter genus is morphologically and structurally very similar to species of the Licea pusilla group, but its plasmodium is still unknown. The sole species of Listerella agrees with Licea operculata in the structure of spore ornamentation, the processes consisting of densely packed granules of high electron density. This structure is quite different from that of L. pusilla and L. minima , where the processes have an internal structure of alternating layers different in electron transparency. Presence of spore-like bodies, different in size and ornamentation from normal spores, have been demonstrated in the border region between stalk and sporangium in L. operculata . This is a feature previously supposed to be restricted to Arcyria and related genera. Using X-ray analysis, calcium has been found in the peridium of several species of Licea . Since environmental factors may influence the presence or absence of calcium, caution should be taken in interpreting differences taxonomically. The similarity in elemental composition between the spores and sporangial lid in L. operculata is interesting, considering the fact that the sporangial lid of Trichia crateriformb has been demonstrated to be composed of spore-like structures.     

甘肃鸡类物种多样性研究

甘肃鸡类有19种,随纬度变化形成了物种多样性梯度。本文通过气候(年无霜天数、元月均温、年均温、7月均温和年降水量),海拔高差,纬度和植被类型多样性与各县鸡类多样性相关统计分析,揭示了7月均温,年均降水量,海拔高差和纬度是控制甘肃鸡类多样性的主要因素,而甘肃鸡类多样性与植被类型多样性无关。在降水量400—650mm和海拔高差1500—3500m的地带种类最多。一个地区物种的多少不仅取决于其离物种库的远近,还取决于这一地区环境空间异质性程度。