Showing papers in "Biologia in 2007"

Bioactive secondary metabolites produced by microorganisms associated with plants

Abstract: In the past few decades groups of scientists have focused their study on relatively new microorganisms called endophytes. By definition these microorganisms, mostly fungi and bacteria, colonise the intercellular spaces of the plant tissues. The mutual relationship between endophytic microorganisms and their host plants, taxanomy and ecology of endophytes are being studied. Some of these microorganisms produce bioactive secondary metabolites that may be involved in a host-endophyte relationship. Recently, many endophytic bioactive metabolites, known as well as new substances, possesing a wide variety of biological activities as antibiotic, antitumor, antiinflammatory, antioxidant, etc. have been identified. The microorganisms such as endophytes may be very interesting for biotechnological production of bioactive substances as medicinally important agents. Therefore the aim of this review is to briefly characterize endophytes and summarize the structuraly different bioactive secondary metabolites produced by endophytic microorganisms as well as microbial sources of these metabolites and their host plants.

Diversity and relationships among Turkish okra germplasm by SRAP and phenotypic marker polymorphism

Abstract: Germplasm characterization is essential and molecular markers provide valuable information for breeding programs. Sequence-related amplified polymorphism (SRAP) and phenotypic markers were studied to determine diversity and relationships among 23 okra (Abelmoschus esculentus (L) Moench) genotypes. The 39 combinations of forward and reverse SRAP primers were used to evaluate the 21 Turkish and two randomly selected USA genotypes as outgroups, and produced 97 scorable markers, of which 50% was polymorphic for all 23 genotypes. Seventeen out of the 23 genotypes (74%) were distinguished from each other with mean similarity of 0.93. As to phenotypic markers, 33 heritable traits were evaluated in field with ten replications, 28 of them (85%) were found to be polymorphic. The UPGMA (unweighted-pair group method arithmetic average) dendrogram based on the 33 phenotypic markers distinguished all genotypes, but failed to detect any geographic association of okra genotypes, being consistent with previous study. It can be concluded that SRAP markers are useful for studying diversity and relationships among okra germplasm, and have potential in marker-aided selection, linkage mapping, and evolutionary studies.

A simple and effective method for protein subcellular localization using Agrobacterium-mediated transformation of onion epidermal cells

Abstract: A modified Agrobacterium-mediated transformation protocol has been successfully used for transient expression of the intrinsically fluorescent proteins and their fusion proteins in onion epidermis. The mean of the transformed cells rate per peel is about 10.5±0.9%, while that of the particle bombardment method is at the range 2.0±0.4%. To compare with the prevailing method of micro-projectile bombardment, the modified Agrobacterium-mediated transformation may provide with higher efficiency and even more simplified manipulability on a lower budget.

Field measurement of soil water repellency and its impact on water flow under different vegetation

Abstract: Numerous recent laboratory studies have shown that vegetation can influence soil water flow by inducing very low levels of water repellency. In this study we extended on this previous research by developing a field-based test using a miniature infiltrometer to assess low levels of water repellency from physically based measurements of liquid flow in soil. The field-based test was verified through a simple laboratory experiment and then applied to determine the impact of vegetation and antecedent soil water content. The soil hydraulic properties determined were hydraulic conductivity, sorptivity, as well as the persistence and index of water repellency. Tests were conducted following a dry spell and wet spell on (1) forest soil (0 cm depth), (2) glade soil (0 cm depth) and (3) glade soil (50 cm depth). It was found that both the persistence and index of water repellency, R, decreased in the order as follows: forest soil > glade soil (0 cm) > glade soil (50 cm) for both dry and wet spell. The range of values of R was 0.28 (wettable) to 360 (highly water repellent), which affected hydraulic conductivity kr(−2 cm). R increased and hence kr(−2 cm) decreased in the order: forest soil < glade soil (0 cm) < glade soil (50 cm) for both the dry and wet spell. There were clear interactions between vegetation and changes to water flow caused by presence of repellency.

Cytotoxic and genotoxic effects of Lavandula stoechas aqueous extracts

Abstract: Lavandula genus is an important member of Labiatae (Lamiaceae) family People use commonly Lavandula stoechas as a medicinal plant for various diseases around the world and also in Turkey The aim of this study was to investigate cytotoxic and genotoxic effects of aqueous extracts (40, 80 and 120 g/L) from L stoechas flowers on Allium cepa root tip meristem cells For this purpose, A cepa onion bulbs were treated with the above-mentioned L stoechas flower extracts for 72 h Spring water (pH 73) was used as a control The result of this study sowed that aqueous extracts reduced mitotic index, but induced chromosome aberrations and mitotic aberrations in comparison with control, significantly (p < 005) Aqueous extracts induced breaks, stickiness, pole deviations and micronuclei Furthermore, these effects were related to extract concentrations These results showed that L stoechas aqueous extracts have cytotoxic and genotoxic effects

Improved Agrobacterium-mediated genetic transformation of GNA transgenic sugarcane

Abstract: Six plasmids carrying a snowdrop lectin (Galanthus nivalis agglutinin, GNA) and one of three selection markers were successfully transferred into two sugarcane cultivars (FN81–745 and Badila) via Agrobacterium-mediated transformation. Agrobacterium strains LBA4404, EHA105 and A281 that harboured a super-binary vector were used for sugarcane transformation. The use of the hygromycin (Hyg) resistance gene (hpt II), phosphinothrincin (PPT) resistance gene (bar) or G418 resistance gene (npt II) as a screenable marker facilitated the initial selection of GNA transgenic sugarcane callus with different efficiencies and helped the rapid segregation of individual transformation events. All the three selective marker genes were controlled by CaMV 35S promoter, while GNA gene was controlled by promoter of RSs-1 (rice sucrose synthase-1) or Ubi (maize ubiquitin). Factors important to successful transformation mediated by Agrobacterium tumefaciens were optimized, which included concentration of A. tumefaciens, medium composition, co-cultivated methods with plant tissue, strain virulence and different selective marker genes. An efficient protocol for sugarcane transformation mediated by A. tumefaciens was established. The GNA gene has been integrated into sugarcane genome as demonstrated by PCR and Southern dot blotting detections. The preliminary results from bioassay demonstrated a significant resistance of the transgenic sugarcane plants to woolly aphid (Ceratovacuna lanigera Zehnther) indicating thus the possibility for obtaining a transgenic sugarcane cultivar with resistance to woolly aphid.

Salinity and salt composition effects on seed germination and root length of four sugar beet cultivars

Abstract: Salinization is one of the most important factors affecting agricultural land in the world. Salinization occurs naturally in arid and semiarid regions where evaporation is higher than rainfall. Sugar beet yield declines with an increase in salinity, but the sensitivity to salts varies with salt composition in water and sugar beet growth stage. The aim of this study was to determine the effect of water salinity levels and salt composition on germination and seedling root length of four sugar beet cultivars (PP22, IC2, PP36, and 7233). The experiments were undertaken with irrigation water with two salt compositions (NaCl alone and mixture of MgSO4 + NaCl + Na2SO4 + CaCl2) in three replicates. Thirteen salinity levels with electrical conductivity (EC) of the irrigation water ranging from 0 to 30 dS/m were applied to each cultivar in both experiments. Seed germination percentage and seedling root length growth were determined in 13 days. Statistical analysis revealed that germination and root length were significantly affected by salt composition, cultivars and salinity levels. Regardless of salt composition, seed germination and seedling root length were significantly affected by the irrigation water with EC up to 8 dS/m and 4 dS/m, respectively. Except for cultivar PP22, the adverse effect of salinity of the irrigation water on seed germination and seedling root length was higher for NaCl alone than for the salt mixture, which refers to lower salt stress in field conditions with natural salt composition.

Isolation of pathogenic bacteria from Oberea linearis (Coleptera: Cerambycidae)

Abstract: The bacterial flora of the Oberea linearis (Coleoptera: Cerambycidae) was investigated and 13 different bacteria were isolated from O. linearis larvae. Seven of these bacteria were performed and characterized at species level and the rest of them were characterized at genus level. In this study, we determined morphological and physiological characteristics of the bacterial isolates by conventional and routine techniques, biochemical properties and metabolic enzyme profiles by API20E and Phoenix 1000A panel test systems. Additionally, 16S rRNA gene sequence analysis was also performed to identify the isolates at the molecular level. The isolates were identified as Acinetobacter calcoaceticus (Ol1), Enterobacter aerogenes (Ol2), Pseudomonas sp. (Ol3), Flavobacterium sp. (Ol4), Microbacterium sp. (Ol5), Enterobacter agglomerans (Ol6), Xanthomonas sp. (Ol7), Pseudomonas syringae (Ol8), Pseudomonas sp. (Ol9), Xanthomonas sp. (Ol10), Enterobacter cancerogenus (Ol11), Xanthomonas maltophilia (Ol12), and Serratia marcescens (Ol13). This is the first record of bacterial isolates (Ol5, Ol8, Ol11, Ol12) from any insect. All these bacteria were tested against O. linearis larvae, and Serratia marcescens was found to cause the highest mortality (65%). On the other hand, we determined 90% mortality against this pest within four days by utilizing spore and crystal mixture of Bacillus thuringiensis isolated from Melolontha melolontha.

Trichome micromorphology in Teucrium (Lamiaceae) species growing in Croatia

Abstract: Micromorphological investigation of the types, dimensions and distribution of characteristic trichomes in leaves and stems in Teucrium L. species (T. arduini L., T. chamaedrys L., T. flavum L., T. montanum L., T. polium L., and T. scordium L. subsp. scordioides Schreb.) distributed in Croatia was carried out as part of the taxonomical study of the genus Teucrium. Secretory types of hairs, peltate and capitate hairs were observed on the epidermis of stems and leaves of all investigated species. Non-secretory, acicular hairs were almost completely lacking on stems of T. scordium subsp. scordioides. Flagelliform hairs were not found in T. flavum and T. polium. Cladose hairs were present only in T. polium. The largest micromorphological variability was established between wild and cultivated samples of T. arduini and T. scordium subsp. scordioides, while cultivated and wild specimens of T. polium were almost identical. Differences were primarily observed in trichome dimensions and much less in micromorphological features.

Benthic macroinvertebrates associated with four species of macrophytes

Abstract: Benthic macroinvertebrates associated with four species of macrophytes (Nymphoides peltata, Ceratophyllum demersum, Polygonum amphibium and Carex sp.) were investigated during two growing seasons (2001 and 2002) in the slow-flowing Conakut Channel in the Kopacki rit Nature Park in Croatia. A total of 31 macroinvertebrate taxa were found. C. demersum, a submerged plant with dissected leaves, supported the highest macroinvertebrate abundance, almost seven times more than N. peltata, a floating plant with undissected leaves, which harboured the lowest abundance during the research period. Chironomidae larvae (50–83%) and Oligochaeta (14–46%) were the most abundant groups recorded on all macrophyte species. Water-level fluctuation, because of its influence on the appearance and growth of aquatic vegetation, and the trophic state of water within the macrophyte stands seemed to be the main factors which affected the taxonomic composition and abundance of macroinvertebrates.

Macroinvertebrates along the Serbian section of the Danube River (stream km 1429–925)

Abstract: Results of the investigation of the aquatic macroinvertebrate fauna along a 504 km stretch of the Danube River in Serbia are presented. A total of 74 macroinvertebrate taxa were observed during a 2001 survey. Oligochaeta and Mollusca were the principal components of the community with regard to species richness and abundance. Based on data on the qualitative composition of the macroinvertebrate fauna, a correspondence analysis divided the investigated stretch in three sectors — upper (Pannonian), Iron Gate sector and entrance sector to the Iron Gate stretch. The distribution patterns of certain species supported the division of sectors defined by correspondence analysis.

Intensified grazing affects endemic plant and gastropod diversity in alpine grasslands of the Southern Carpathian mountains (Romania)

Abstract: Alpine grasslands in the Southern Carpathian Mts, Romania, harbour an extraordinarily high diversity of plants and invertebrates, including Carpathic endemics. In the past decades, intensive sheep grazing has caused a dramatic decrease in biodiversity and even led to eroded soils at many places in the Carpathians. Because of limited food resources, sheep are increasingly forced to graze on steep slopes, which were formerly not grazed by livestock and are considered as local biodiversity hotspots. We examined species richness, abundance and number of endemic vascular plants and terrestrial gastropods on steep slopes that were either grazed by sheep or ungrazed by livestock in two areas of the Southern Carpathians. On calcareous soils in the Bucegi Mts, a total of 177 vascular plant and 19 gastropod species were recorded. Twelve plant species (6.8%) and three gastropod species (15.8%) were endemic to the Carpathians. Grazed sites had lower plant and gastropod species richness than ungrazed sites. Furthermore, grazed sites harboured fewer gastropod species endemic to the Carpathians than ungrazed sites. On acid soils in the Fagaras Mts, a total of 96 vascular plant and nine gastropod species were found. In this mountain area, however, grazed and ungrazed sites did not differ in species richness, abundance and number of endemic plant and gastropod species. Our findings confirm the high biodiversity of grasslands on steep slopes in the Southern Carpathian Mts and caution against increasing grazing pressure in these refuges for relic plants and gastropods as well as for other invertebrates.

Formal definitions of Slovakian mire plant associations and their application in regional research

Abstract: We applied the Cocktail method to a large data set of 4 117 releves of all Slovak vegetation types with the aim to create formalised definitions of all Slovakian mire plant associations. We defined 21 groups of species with the statistical tendency of joint occurrences in vegetation. These groups differed substantially in their position along the pH/calcium gradient. We further defined 24 plant associations according to presence and/or absence of certain groups and/or strong dominance of some species. Only six traditional plant associations were not possible to be reproduced this way. We applied our formalised definitions to the regional data set of mires from the surrounding of the Vysoke Tatry Mts. Combined with frequency-positive fidelity index this method has led to the classification of the majority of vegetation plots into ten associations. When the vegetation types obtained from Cocktail-based classification and from cluster analysis were compared with respect to measured pH and conductivity in the study region, 82% of pairs differed significantly either in pH or in water conductivity in the former classification and 69% in the latter one.

Woodland mollusc communities along environmental gradients in the East Carpathians

Abstract: Mollusc communities were sampled quantitatively at eleven sites representing different environmental conditions in the Bieszczady National Park (East Carpathians Mts, Poland). Overall 61 species were recorded. Alder forest in the valleys (AF; Alnetum incanae carpathicum, Caltho-Alnetum, secondary alder forest) hosted the richest fauna, with up to 41 species occurring sympatrically on 100 m2 of forest floor and average density ca. 750 specimens m−2. Three important ecological controllers of species composition and community structure were found. The main predictor of mollusc assemblage composition was calcium content; the first DCA axis of molluscs most significantly and highly correlated with calcium content in the leaf litter and organic matter in the upper layer. The second axis significantly correlated with altitude and negatively with annual temperature, and thus can be explained as an elevational gradient. We observed slope aspect to constitute the third significant gradient. On the basis of forward selection in CCA analysis organic matter in the upper layer of soil was the best predictor of species composition, which explained 26% of total variance. It comes to prove that in mountain forest on non-calcareous bedrock molluscs obtain calcium mainly from leaf litter.

Syntaxonomic diversity as an indicator of ecological diversity — case study Vranica Mts in the Central Bosnia

Abstract: Syntaxonomic diversity (SD) represents the number of plant communities (phytocoenoses) in certain area. Plant communities as organized systems of populations of various coexisting plant species inhabiting same or similar habitat in the function of time. SD is one of the best indicators of the state and potential carrying capacity of every ecosystem and an attribute of total ecological diversity. In general, level of syntaxonomic diversity indicates habitat heterogeneity and diversity. This could have significant importance in the categorization of habitat values in accordance with European Nature Information System (EUNIS) criteria. The results presented in this paper indicate without any doubt high natural values of mountain range Vranica in Bosnia and Herzegovina. One of the best proofs is an extremely high level of syntaxonomic diversity. In this area covering just 288 km2, vegetation is differentiated into 9 formations, 28 classes, 44 orders, 73 alliances and 165 associations. This represents 85% of all classes, 73% of all orders, 65% of all alliances, and 53% of all associations of vegetation in Bosnia and Herzegovina, or 35% of all classes in vegetation diversity in Europe. Going from the level of class to the level of order, the number of syntaxa increases for 61%, from order to alliance for 60%, and from alliance to association for 44.24% (average 55%). SD index is very high and it is 0.5729. This means that on each km2 contains 0.5729 syntaxa.

Arthropods (Pseudoscorpionidea, Acarina, Coleoptera, Siphonaptera) in nests of the bearded tit (Panurus biarmicus)

Abstract: In the period 1993–2006, during investigation of reproduction biology of the bearded tit, 106 deserted nests of the species were collected in Slovakia, Austria and Italy and their arthropod fauna was analyzed. Occasionally introduced individuals of the pseudoscorpion Lamprochernes nodosus, a frequent species in Central Europe, were recorded in the nests. Altogether 984 individuals and 33 species of mesostigmatic mites (Acari) were found in 46.2% of the nests examined. The ectoparasite Ornithonyssus sylviarum was most abundant and frequent; it represented almost 68.3% of all individuals. Due to it, the parasitic mites predominated (69.4% of individuals). Other ecological groups were less represented: edaphic detriticols − 11.6%, coprophils − 10.7%, species of vegetation stratum − 8.2%, and nidicols − 0.2%. Beetles (40 species, 246 individuals) were present in 57 nests. Most of the beetles were strongly hygrophilous species inhabiting soil surface in the reed stands or other types of wetlands and the shore vegetation. Predators represented 59% of all individuals. They might find food in the nests, but none of the species had a close relationship to bird nests and represented 35% of species. All beetle species penetrated the nests occasionally, when ascending on the vegetation or searching cover during periods of increased water level. Occasionally, larvae and nymphs of the Dermacentor marginatus tick were found. They were most probably introduced by insectivores of the genus Neomys. Only one species of fleas, Ceratophyllus garei — a parasite of birds nesting in humid environment, was recorded in the nests.

Liver and muscle fatty acid composition of mature and immature rainbow trout (Oncorhynchus mykiss) fed two different diets

Abstract: Fatty acid composition of liver and muscle tissues of immature and mature Oncorhynchus mykiss fed on two different diets were determined. Fatty acid analyses were carried out by gas chromatography. Palmitic acid (C16:0), oleic acid (C18:1 n-9), linoleic acid (C18:2 n-6) and docosahexaenoic acid (C22:6 n-3) were the major components in both liver and muscle tissues of immature and mature rainbow trout of both sexes. The amounts of C22:6 n-3 were higher in the liver (29.04 ± 0.06 − 27.41 ± 0.17%) and muscle (13.05 ± 0.40 − 11.37 ± 0.21%) of immature fish than in mature fish and depended on the composition of the diet. Results of this study show that fatty acid composition in fish tissues can considerably vary, depending on the age of fish and their diet. Thus more detailed studies are necessary on the influence of diet on immature and mature fish fatty acid composition. The age and diet of fish consumed may also be important for human health.

Effect of vitamin E and selenium on antioxidant enzymes in brain, kidney and liver of cigarette smoke-exposed mice

Abstract: The present study was conducted to evaluate the protective effects of vitamin E and selenium (Se) application on alteration of antioxidant enzyme activities against cigarette smoking induced oxidative damage in brains, kidneys and liver of mice. Male mice (balb/c) were exposed to cigarette smoke and treated with Se and/or vitamin E. Glutathione transferase (GST), glutathione peroxidase (GPX), glutathione reductase (GRX), superoxide dismutase (SOD) and catalase (CAT) enzyme activities in mice brain, kidney and liver were measured spectrophotometrically. GST, GPX, GRX, SOD and CAT enzyme activities in the brains of smoke-exposed mice were found lower than the enzymes activities of control mice and Se-and vitamin E-treated mice at the end of the three and five months. Opposite to brain, enzyme activities in kidneys and livers of smoke-exposed mice were found higher than the enzymes activities of control mice and Se-and vitamin E-treated mice at the end of the three and five months. Activities of GST, GPX, GRX SOD and CAT in the livers, kidneys and brains of smoke-exposed mice were found statistically different (p < 0.01) compared to control mice and Se-and vitamin E-treated mice. Combined application of vitamin E and Se had an additive protective effect against changing enzymes activities in smoke-exposed mice livers, kidneys and brains at the end of the both application periods. These results suggest that cigarette smoke exposure enhances the oxidative stress, thereby disturbing the tissue antioxidant defense system and combined application of vitamin E and Se protects the brain, kidney and liver from oxidative damage through their antioxidant potential.

Assessment of antibacterial effects of flavonoids by estimation of generation times in liquid bacterial cultures

Abstract: Antibacterial activities of various flavonoids, a group of natural plant substances, have been reported previously, however, there are contradictory data, published by various authors, regarding sensitivity of particular bacterial species to these compounds. These problems arose apparently because of using different methods by various researchers. Here we tested sensitivity of several bacterial species (Gram-positive: Bacillus subtilis, Micrococcus luteus, Sarcina sp. and Staphylococcus aureus; and Gram-negative: Citrobacter freundii, Escherichia coli, Klebsiella pneumoniae, Proteus vulgaris, Pseudomonas aeruginosa, Salmonella enterica, Serratia marcescens and Vibrio harveyi) to various flavonoids: genistein and daidzein (isoflavones), apigenin (a flavone), naringenin (a flavanone) and kaempferol (a flavonol) by measurement of generation times of bacteria in liquid cultures. The presented results indicate that this simple method is adequate for unambiguous assessment of sensitivity of bacterial strains to flavonoids.

Population dynamics of wireworms (Coleoptera, Elateridae) in arable land after abandonment

Abstract: The community of elaterid larvae of three sites (field and two fallows), representing different stages of secondary succession, were studied using soil sampling from 1986 to 1993. All three sites were abandoned arable land: a field cultivated until 1991, a fallow I abandoned in 1986, and a fallow II abandoned about 1976. The fallow II was used as a meadow after abandonment and was regularly mown until 1985, when cultivation stopped. Six species of Elateridae larvae were found at all three study sites. In the field, Agriotes obscurus, Athous niger, Athous subsuscus, Dalopius marginatus and Athous vittatus were found, A. niger and A. obscurus being the most abundant species. During cultivation, larval densities were very low, however, larval abundance increased up to 8.8 ± 8.3 ind. m-2 when cultivation stopped. Only small A. obscurus larvae were found during cultivation, whereas larval size increased after abandonment. In fallow I A. obscurus, A. niger, A. subsuscus, D. marginatus, and Agrypnus murinus were found and the average annual abundance fluctuated between 0.8 ± 1.4 to 40.8 ± 10.9 ind. m-2 with A. obscurus being the most abundant species. Fallow II supported the highest densities of wireworms from all plots studied (71.2±35.2 to 280.0±24.8 ind. m-2). A. obscurus, A. niger, A. subsuscus and D. marginatus were found in fallow II. The abundance of all larval Elateridae as well as the dominant species A. obscurus decreased during the study period, while simultaneously the occurrence of small sized A. obscurus larvae decreased. The frequency of cultivation and time elapsed since last cultivation appeared to be the most important factors affecting elaterid occurrence in the field and fallow I. In fallow II, the decrease in abundance correlates with the accumulation of a dense litter layer, which may correspond with soil surface structure, plant community changes or predator pressure.

Morpho-histological study on shoot bud regeneration in cotyledon cultures of pepper (Capsicum annuum)

Abstract: Adventitious organogenetic structures were produced in vitro using cotyledon explants excised from 14 day-old pepper seedlings. The best response was observed on MS medium containing 5.7 μM indole-3-acetic acid and 8.8 μM 6-benzylaminopurine. However, when transferred onto elongation medium (MS + 2.8 μM gibberellic acid), these structures frequently developed into leaf-like features rather than into normal shoots. Interestingly, the histological study conducted on the cut end of the cotyledonary petiole revealed a direct induction of numerous teratological protuberances that arise around the cut end of the explant. On the contrary, typical organized bud meristems were rarely observed. Thus, the low number of plants obtained after transfer onto elongation medium seems to be a consequence of this teratological developmental process, frequently associated with fasciated and degenerative meristems, rather than a defect in shoot development from available meristems.

Aphids (Hemiptera: Aphidoidea) on cultivated and self-sown plants in Greece

Abstract: The present work covers original information on aphids (Hemiptera: Aphidoidea) from Greece during 1995–2005. The individual aphid taxa were collected from their host plants and identified. The plant taxa were classified in two major categories: cultivated and self-sown. The cultivated ones were classified as: herbaceous, climbing and trees. The selfsown ones were classified as: annual herbaceous, annual or biennial herbaceous, biennial or perennial herbaceous, perennial herbaceous, shrubby and trees Two hundred twelve plant taxa were identified on which 105 aphid taxa were recorded. We report 391 plant taxa-aphid taxa associations from which, 190 are referred to cultivated and 201 to self-shown plant taxa. Aphis gossypii was found to infest the widest spectrum of cultivated plant taxa whereas Brachycaudus helichrysi was found to infest the widest spectrum of self-sown plant taxa. Myzus persicae was found to infest the widest spectrum of the total number of plant taxa. Information for several economically unimportant aphid taxa in the area are also presented.

Size spectra and abundance of planktonic ciliates within various habitats in a macrophyte-dominated lake (Eastern Poland)

Abstract: Body size, community structure, abundance and biomass of ciliates were compared in various stands of macrophytes in a macrophyte-abundant shallow lake in Eastern Poland. Samples were collected in belts of Phragmites, Typha, Ceratophyllum, Elodea, Stratiotes and Chara. Additionally, protozooplankton was collected from the open water zone surrounding the vegetation belts. Differences in numbers of ciliate taxa between micro-sites were statistically significant. The highest numbers were found in Chara and Ceratophyllum stands, lower numbers in Stratiotes and Elodea stands and the lowest in the open water, Phragmites and Typha areas. Ciliate biomass was, like density, significantly higher in submerged macrophytes than in emergent macrophytes and open water zones. Based on differences in macrophyte structure, two groups of habitats with similar patterns of size-related ciliate distribution were distinguished. The first group consisted of two vegetated zones of sparse stem structure (Phragmites and Typha) and the open water zone, the second group comprised submerged macrophyte species, which were more dense and complex. Generally, the abundance of ciliates correlated positively with total suspension solid (TSS) and total organic carbon (TOC) concentrations. In the Chara and Ceratophyllum stands, relations between ciliate numbers, TSS and TOC were stronger.

Fluorescence in situ hybridisation

Abstract: Fluorescence in situ hybridisation (FISH) is a rapid and reliable technique for chromosomal investigations that is used for a wide variety of cytogenetic purposes at present. This molecular-cytogenetic method has been developed continuously for many years. As a consequence, various modifications with different kinds of fluorescently labelled probes have been introduced to optimise the detection of DNA and RNA sequences. This review articlepaper presents the general principles of in situ hybridisation, probe labelling and examples of proper use of different kinds of probes. In addition, some newer FISH methods and their usefulness in human molecular cytogenetics are described.

Chlorophyll a extraction from freshwater algae — a reevaluation

Abstract: In this study, two extracting methods (sonication and dispersing) and three solvents (90% acetone, N,N′-dimethylformamide and methanol) were compared for their ability to extract chlorophyll a of freshwater phytoplankton Measurements were performed with both spectrophotometry and high-performance liquid chromatography Results showed that (i) cell disruption is essential and that (ii) the method of cell disruption and solvent applied differed significantly Dispersing in acetone surpassed all other combinations Sonication in N,N′-dimethylformamide was found less effective N,N′-dimethylformamide and methanol seem to promote the formation of degradation products (chlorophyllide a, allomer, epimer and phaeophytin a) which lead to overestimates of chlorophyll a of about 10% by means of spectrophotometry

New species and records of mites (Acari, Prostigmata: Erythraeidae, Trombidiidae, Eutrombidiidae) from the Balkan Peninsula

Abstract: Arknotrombium arknesianum gen. n., sp. n., Hauptmannia kotorensis sp. n., both from Montenegro, H. podorasensis sp. n. and Abrolophus pseudolongicollis kiejstuti subsp. n., both from Bosnia and Hercegovina are described. Leptus mariae Haitlinger is new to the fauna of Bulgaria, Leptus josifovi Beron is new for the fauna of Bosnia and Hercegovina, Erythraeus budapestensis Fain et Ripka is new for the fauna of Bosnia and Hercegovina and Montenegro, Allothrombium fuliginosum (Hermann) is new for the fauna of Bosnia and Hercegovina, Bulgaria and Serbia and Eutrombidium trigonum (Hermann) is new for the fauna of Bulgaria. Redescription of Erythraeus styriacus Turk is given.

The potential of Rhizobium strains for biological control of Orobanche crenata

Abstract: Orobanche crenata Forsk is a chlorophyll lacking holoparasite that subsists on the roots of plants and causes significant damage to the culture of leguminous plants and, in particular, to peas (Pisum sativum L.). Here, we investigated the potential of Rhizobium strains for biological control of Orobanche crenata using a commercial pea cultivar (Douce de province) and different Rhizobium strains. Firstly, benefit of bacterial inoculation on plant growth and efficiency in N-incorporation were demonstrated with four isolates, P.SOM, P.1001, P.Mat.95 and P.1236. After five Rhizobium strains (three efficient: P.SOM, P.1236, P.Mat.95 and two not efficient: P.OM1.92, P.MleTem.92) were investigated for their ability to control Orobanche crenata using pot and Petri dish experiments. Inoculation of peas with two (P.SOM and P.1236) of the five strains induced a significant decrease in O. crenata seed germination and in the number of tubercles on pea roots. Furthermore, other symptoms, including the non-penetration of the germinated seeds into pea roots followed by radicle browning and death of the parasites, were observed in the presence of these inoculated pea plants. The hypothesis that roots secrete toxic compounds related to Rhizobium inoculation is discussed.

Biosorption of Co2+ ions by lichen Hypogymnia physodes from aqueous solutions

Abstract: Cobalt is one of the possible contaminants originating from radioactive wastes or from metal mines and refineries. This paper describes sorption of cobalt by the foliose lichen Hypogymnia physodes from CoCl2 solutions spiked with 60Co2+ in laboratory experiments. Maximum uptake was reached within 1 hour; the biosorption after 24 hours is not pH-dependent within the range of pH 4–7, negligible at pH 2 and is not dependent on metabolic activity. The process can be described by the Freundlich adsorption isotherm with ln k = 2.77, 1/n = 0.22 and R 2 = 0.94. Bivalent metal ions showed a concentration-dependent competitive effect on cobalt biosorption, decreasing in the order: Cu > Ni > Ca > Mg. Monovalent ions, such as K+ and Na+, showed only very weak competitive effect. Up to 98% of Co taken up by lichen can be removed by washing with 0.1 M NiCl2 at 20°C. This means that only a small fraction of the cobalt is localized intracellularly. These results can be used for elucidating the behaviour of lichens as bioindicators of cobalt pollution in water systems, including the risk of cobalt leakage from lichen probes under the influence of rain, snow and atmospheric humidity.

Jumping cockroaches (Blattaria, Skokidae fam. n.) from the Late Jurassic of Karatau in Kazakhstan

Abstract: The jumping cockroach Skok svaba gen. et sp. n., characteristic of modern reproduction, is described from the Upper Jurassic Karabastau Formation in Kazakhstan, and attributed to a new family Skokidae. The finding demonstrates the immense plasticity of stem cockroaches from which eusocial termites and predatory mantises evolved.

Macrophomina phaseolina causing a charcoal rot of sunflower through Slovakia

Abstract: The fungus Macrophomina phaseolina distributed especially in warmer region of Europe is reported for the first time from the Slovakia as a pathogen of sunflower. Morphology of its populations is characterized.