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1

Medical significance of nematodes

Nieradko-Iwanicka Barbara, Chodun-Wróblewska Wiktoria

Polish Hyperbaric Research

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2023

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nr 3(84)

41--56

EN

Nematodes are invertebrates that can cause parasitic diseases in humans, animals and plants. These organisms also participate in the decomposition of dead remains of organisms. In recent years, new reports have appeared on the possibility of using intentional nematode infections in the treatment of autoimmune and neurological diseases. The aim of this work is to summarize information about nematodes pathogenic to humans and the possibilities of therapeutic use of some nematodes. 36 original and review publications from 2008-2022 were analyzed. Information was collected on 13 diseases caused by parasitic nematodes in humans (reservoir, routes of infection, susceptible organisms, symptoms of infection). Current publications on trials of using Trichuris suis eggs (TSO) in animal models, in healthy humans and in people with inflammatory bowel diseases (IBD) or autism spectrum disorder (ASD) or multiple sclerosis (MS) are summarized. Clinical improvement was observed in some of the subjects. However, researchers draw attention to the depletion of the biodiversity of the host's intestinal microbiota in the presence of TSO. Conclusions: The results of research on the therapeutic use of TSO remain inconclusive. There are many more diseases caused by parasitic nematodes in humans than there are documented therapeutic effects of TSOs. Exposure to parasitic nematodes’ eggs (especially Toxocara canis and Toxocara cati) is still very common.

2

Soil conditions under great cormorant and grey heron colonies in a wetland : Effect on soil nematode abundance and trophic structure

Kozacki Dawid, Ilieva-Makulec Krassimira, Hryniewicz Marek, Makulec Grzegorz

Journal of Water and Land Development

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2023

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no. 58

79--88

EN

This study aimed to investigate how great cormorants and grey herons affect the density and trophic diversity of soil nematodes under breeding colonies located in Stawy Raszyńskie Nature Reserve (central Poland). Soil samples from the colonies were compared to control samples from adjacent areas unaffected by birds. Samples were taken at each site (two colonies and two relevant control sites) to a depth of 20 cm, and the soil cores were split into topsoil (0-10 cm) and subsoil (10-20 cm). A modified Baermann method was used to extract nematodes from the soil. The soil under nests supported more abundant nematode communities, but with a lower trophic diversity compared to the control sites. The cormorants had a greater impact on nematodes than the herons. We found that the external nitrogen input, the higher organic matter content and abundance of ammonifying bacteria, as well as the lower soil pH under the colonies than in the control sites, affected the nematode trophic groups in different ways. Compared to the control sites, there were significantly more bacterivorous nematodes but fewer herbivorous nematodes under the colonies. No predatory nematodes were found under the bird colonies and, in the case of the cormorant colony, no omnivorous nematodes. No significant differences in the abundance of fungivorous nematodes between the impact and the control plots were noticed. The results indicate that allochthonous input under bird colonies promotes microbial activity and the most opportunistic trophic group of nematodes, which may at least temporarily enhance decomposition and mineralisation processes and consequently affect nutrient cycling in the wetland soil.

3

Species composition and structure of the nematode communities of epiphytic mosses in the Left-bank Polesie (Ukraine)

Shevchenko Valentyna, Zhylina Tetiana

Studia Quaternaria

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2021

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Vol. 38, Nr 2

143--148

EN

Species and generic composition of nematode communities from the epiphytic mosses in the Left-bank Polesie were studied. Nematodes were extracted by a modified Baermann’s method. A total of 47 species was found and they belonged to 34 genera, 21 families and 8 orders. The average number of nematodes was 4077 per 100 g of the moss. Rhabditida, Tylenchida, Plectida and Dorylaimida composed had more species richness (12, 10, 8 and 7 species, respectively). Species of these four orders comprised 78.7%. Representatives of three order Plectida, Dorylaimida and Monhysterida were the most numerous within the considered communities (proportion in the communities were 40.75, 21.30 and 18.65%, respectively). The majority of the identified species were subrecedent (31 or 65.95% of species composition) and accidental species (37 or 78.72%). Three species: Plectus parietinus Bastian, 1865, Mesodorylaimus bastiani Bütschli, 1873 and Geomonhystera villosa Bütschli, 1873 composed the core of nematode communities from epiphytic mosses in the Left-bank Polesie. They were found in 70.21, 57.45 and 53.19% of the samples, proportion in the community of 15.21, 10.03 and 17.96%, respectively.

4

Meiobenthic assemblage of the grey mangrove (Avicennia marina) along the Saudi Arabian coast of the Red Sea with emphasis on free-living nematodes

Al-Sofyani A., El-Sherbiny M.

Oceanological and Hydrobiological Studies

|

2018

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Vol. 47, No. 4

359--375

EN

Spatial variability in the population density of meiofauna and the assemblage of free-living marine nematodes was studied at 20 mangrove sites located along the Saudi Arabian coast of the Red Sea. The total abundance of meiofauna varied between the locations and ranged from 119 to 1380 ind. 10 cm-2. A total of seven main taxa were recorded. Nematodes dominated (64.3%) in all sediment samples. They were followed by harpacticoid copepods (13.2%) and polychaetes (12.9%) with significant differences in their density between the locations surveyed (p < 0.001). The Pearson correlation analysis showed significant positive correlations between the sand fraction and nematodes, harpacticoid copepods and turbellarians. Twenty-five genera of free-living nematodes belonging to 15 families were recorded in the study area. Microlaimidae were the most abundant family, while Xyalidae, Desomodridae and Chromidoridae were the most diverse families. Microlaimus, Halalaimus and Terschellingia were the most frequent genera. ANOSIM values obtained for the distribution of different nematode genera in various habitats showed no significant differences. Feeding types of different nematode genera were also documented and the epistrate feeders along with the deposit feeders were found to be the common feeding types in the present study.

5

Distribution of ascaridoid nematodes (Nematoda: Chromadorea: Ascaridoidea) in fish from the Barents Sea

Najda K., Kijewska A., Kijewski T., Plauška K., Rokicki J.

Oceanological and Hydrobiological Studies

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2018

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Vol. 47, No. 2

128--139

EN

The Ascaridoidea are parasites with heteroxenous life cycles. The study shows that fish can be paratenic, intermediate, or final hosts for parasites, and parasitic fauna reflects the feeding behavior of the hosts. Each species of parasites has also different environmental preferences and host specificity. Parasitic nematodes of fish representing Pleuronectidae, Gadidae, Sebastidae, and Macrouridae were studied. Worms were collected separately from different infection sites: stomach, intestine, liver and body cavity. Nematodes were identified using both morphological and molecular methods (PCR-RFLP). Six nematode species were recorded: Anisakis simplex s.s., Contracaecum osculatum A, B, and C. osculatum C (s.s.), Hysterothylacium aduncum and Pseudoterranova bulbosa. Anisakis simplex s.s. was the most numerous nematode species of all catches combined. Differences in parasite species composition were related to the depth and location of sampling areas. In the fish from deep waters, the abundance of A. simplex s.s. decreased compared to fish from shallow waters and P. bulbosa was the dominant species. Ascaridoid species have specific preferences regarding the impact on various internal organs of fish, which is reflected in their abundance. The presence of Ascaridoidea in the Barents Sea is associated with the distribution of hosts and varying food preferences related to the age of fish. The abundance of parasites varied between different host species.

6

Zmiany w przeżywalności owadobójczych nicieni podczas przepływu przez otwór w dyszy opryskiwacza

Chojnacki J.

Journal of Research and Applications in Agricultural Engineering

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2011

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Vol. 56, nr 1

26-31

PL

Wyznaczono wartości przeżywalności względnej owadobójczych nicieni w cieczy przepływającej wielokrotnie przez dysze. Średnice otworów dyszy wynosiły 0,8 i 1,5 mm. Wartości ciśnienia cieczy przyjętego do badań wynosiły 0,5 i 2,0 MPa.. W przeprowadzonych badaniach użyte zostały nicienie Heterorhabditis bacteriophora i Heterorhabditis megidis.

EN

There were estimating values of a relative viability of entomopathogenic nematodes contained in liquid repeatedly flowing through nozzles. Diameters of the nozzle orifices were 0,8 and 1,5 mm. Values of a liquid pressure taken to the experiments were 0,5 and 2,0 Mpa. In the study were used the nematodes: Heterorhabditis bacteriophora and Heterorhabditis megidis.

7

Wpływ przepływu cieczy przez zawór regulacyjny w instalacji opryskiwacza na przeżywalność owadobójczych nicieni

Chojnacki J.

Journal of Research and Applications in Agricultural Engineering

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2011

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Vol. 56, nr 1

19-25

PL

Przepływ cieczy, zawierającej owadobójcze nicienie, przez szczeliny zaworów regulacyjnych w instalacji opryskiwacza może powodować śmierć części tych żywych organizmów. Oszacowano rozmiar tych szkód posługując się przeżywalnością względną nicieni. Badania przeprowadzono przy wielokrotnym przepływie nicieni poprzez szczelinę zaworu i ciśnieniach cieczy równych 0,50, 1,05 i 1,60 MPa. Najmniejszy spadek przeżywalności stwierdzono przy wartości ciśnienia 0,50 MPa i natężeniu przepływu 0,33 dm3s~'. Stwierdzono, że wyższe wartości ciśnienia cieczy i mniejsze natężenie przepływu powodowały znaczne obniżanie przeżywalności nicieni.

EN

A flow of liquid containing entomopathogenic nematodes through gap of control valves in sprayer installation can cause death of apart of these living organisms. The range ofthose damages were assessed using a relative nematode viability Experiments were carried out with multiple flow of nematodes through valve gap when the liquid pressures were equal to 0,50; 1,05 and 1,60 MPa. The least fall of viability was observed when the value of pressure was 0,50 MPa and the liquid flow was equal to 0,33 dm3-s-1. Generally there was observed that higher values of the liquid pressures and smaller values of liquid flow ranges caused an appreciable decreasing of relative nematode viability.

8

Przeżywalność owadobójczych nicieni w mieszadle strumieniowym

Chojnacki J.

Journal of Research and Applications in Agricultural Engineering

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2011

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Vol. 56, nr 2

27-31

PL

Przeprowadzono badania nad zmianami przeżywalności nicieni Stejnernema feltiae, które przepływały wielokrotnie przez mieszadło strumieniowe stosowane w instalacjach opryskiwaczy. Średnice dysz mieszadła wynosiły od 1,2 do 3,0 mm, maksymalna wartość ciśnienia cieczy wyniosła 2,0 MPa, a wielokrotność przepływu od 0 do 40 razy. Na podstawie wyników badań opracowano równanie regresji. Stwierdzono, że spadek przeżywalności nicieni jest zależny od różnicy pomiędzy iloczynem ciśnienia cieczy i wielokrotności przepływu a iloczynem ciśnienia cieczy, wielokrotności przepływu i rozmiaru średnicy dyszy w mieszadle.

EN

There were performed the investigations of the changes in viability of nematodes - Stejnernema feltiae, which repeatedly flew through a jet agitator applied in sprayer installations. The diameters of the agitator nozzles were from 1,2 to 3,0 mm, the maximum value of liquid pressure was 2,0 MPa and the multiplicity of liquid flow was from 0 to 40 times. The regression formula was calculated on the basis of the experiments results. There was noticed that decrease of the nematode viability depends on difference between a mathematical product of liquid pressure and flow multiple and the mathematical product of liquid pressure, flow multiple and diameter of the agitator nozzle.

9

Pomiary liczby poruszających się owadobójczych nicieni przy wykorzystaniu komputerowej analizy obrazu

Chojnacki J., Kania M.

Pomiary Automatyka Kontrola

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2010

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R. 56, nr 6

566-568

PL

Przedstawiono badania nad zastosowaniem programu komputerowego do zmierzenia liczby poruszających się w próbach cieczy owadobójczych nicieni. W opracowanym programie komputerowym wykorzystano analizę zmian położenia środków ciężkości obserwowanych obiektów na podstawie serii zdjęć wykonanych za pomocą kamery cyfrowej zamontowanej na mikroskopie. Podczas badań wyznaczono zakres przemieszczenia akceptowalnego środków obiektów, dla którego uzyskano najdokładniejsze wyniki pomiarów.

EN

Results of a study carried out to check a computer program for quantification of entomopathogenic nematodes moving in a liquid sample there are presented in the paper. Nematodes are a component of many biological pesticides used in plant protection, in particular in organic agriculture. In order to define the quality of biopesticides, it is necessary to quantify the live nematodes. Infectious juveniles of entomopathogenic nematodes Steinernema feltiae were the material used in this study. Concentration of the larvae was approximately 140 items in 1 mililiter of liquid. Samples of liquid containing nematodes were photographed in time intervals of 5, 10, 15 and 20 seconds with a digital camera mounted on a microscope. The photographs were subsequently introduced into the computer program prepared in LabView 7.0 by National Instruments Compa-ny. Changes in placements of centers of gravity in the objects between pairs of binary displays were analyzed. The program cal-culated translocation of inertia centers of all objects between their location in first and second photographs. Based on the trials, translocation value and interval time between photographs were selected in order to obtain high accuracy of measurements of moved objects. Calculation results of moved nematodes obtained from the computer program were compared with the results made by researcher's analysis of the same photographs. The results obtained from both methods were identical within the translocation range 1.6 - 4.0 pixels and interval times of 10 and 15 seconds between photographs. Study results indicate the possibility of practical implementation of this developed program for quantification of living nematodes.

10

Wpływ temperatury otoczenia na intensywność poruszania się owadobójczych nicieni

Chojnacki J.

Journal of Research and Applications in Agricultural Engineering

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2010

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Vol. 55, nr 3

37-39

PL

Przeprowadzono analizę zmian aktywności ruchowej owadobójczych nicieni Steinernema feltiae w zakresie temperatury otoczenia od 4 do 39°C. Do obliczania liczby poruszonych nicieni zastosowano program komputerowy do analizy obrazu. Do programu wprowadzano serie zdjęć cieczy zawierającej nicienie, które wykonane zostały za pomocą kamery cyfrowej zamontowanej na mikroskopie. Obliczano wartość względnej ruchliwości nicieni, która w obszarze temperatury od 4 do 30°C nie zmieniała się istotnie i wyniosła przeciętnie 65,5%. Przy temperaturach powyżej 30°C aktywność ruchowa spadła istotnie. Było to spowodowane śmiercią nicieni.

EN

There were made an analyze of a mobility changes of entomopathogenic nematodes Steinernema feltiae at ambient temperatures from 4 to 39°C. In order to make estimation of number of moved nematodes a computer program for image analyzes was used. The computer program based on series of a photos of containing nematodes liquid samples. The photos were made by means of a numeric camera mounted on microscope. The values of nematode relative mobility did not differ significantly in the range of temperature from 4 to 30°C and were middle 65,5%. At the temperatures upper than 30°C values of the relative mobility dropped significantly. It was caused by death of nematodes.

11

Combined effects of earthworms and diurnal temperature fluctuations on successional changes of litter nematode community

Uvarov A., Kolosova N., Kulinich O.

Polish Journal of Ecology

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2009

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Vol. 57, nr 4

685-696

EN

Earthworm functioning and temperature regime are among the most important biotic and abiotic factors of soil environment; their combined action on soil nematode activities has not been studied. In a 4-month laboratory experiment, effects of the epigeic earthworm Dendrobaena octaedra on a succession of nematode community in litter of a mid-European birch/oak forest were tested in the gradient of an increase of diurnal temperature fluctuations from 0[degrees]C (constant 15[degrees]C; T[15]) to 10[degrees]C (daily range between 10[degrees] and 20[degrees]C; T[10-20]) and 20[degrees]C (daily range between 5[degrees] and 25[degrees]C; T[5-25]). Earthworm and temperature effects were measured as differences in nematode community respiration rates between the experimental treatments. Nematode respiration rates were calculated on the basis of body size/weight/O[2] consumption relationships for individual species. Nematode community was dominated by bacterial feeders and changed in a characteristic successional pattern which, however, was markedly modified by temperature regime and earthworm activities. Dominant nematode taxa revealed specific patterns of temporal dynamics in connection with their responses to temperature and earthworm presence. Thus, metabolic activity of Plectus acuminatus was strongly reduced by D. octaedra but did not react to variation of temperature regime. In contrast, activity of Panagrolaimus sp. significantly responded to temperature but not to earthworm presence, whereas Pl. thornei reacted to both factors separately and in combination. Ceratoplectus armatus was stronger affected by earthworm presence then by temperature; Tylocephalus auriculatus showed the opposite pattern. The variety of responses may explain the coexistence of several taxonomically related (Plectidae) and trophically similar species within the dominant group. Both earthworm presence and increase of the range of diurnal temperature fluctuations strongly affected the net of interspecific correlations within the nematode community. Earthworms strongly reduced total activities of nematode community at any temperature regime. T[15] regime showed markedly lower level of cumulative nematode respiration than both fluctuating regimes, irrespective of earthworm presence. In conclusion, combined effects of earthworms and temperature regime drastically changed patterns of relationships within the nematode litter community. The results of the experiments may have implications for the perspectives of global warming events at the study site: it is suggested that the ultimate vector of the changes in litter environment might be directed towards the conditions of the treatment [T[15] regime; earthworms present], with the corresponding trends in the development of the litter nematode community.

12

Stężenie biologicznych środków ochrony roślin w opryskiwaczach taczkowych

Chojnacki J.

Inżynieria Rolnicza

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2008

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R. 12, nr 1(99)

77-82

PL

Badano efektywność hydraulicznego systemu mieszania stosowanego w opryskiwaczu taczkowym poprzez pomiary stężenia w wodzie owadobójczych nicieni Heterohabditis bacteriophora. Badania wykonano przy ciśnieniach mieszania: 0.30/0.15, 0.70/0.40 i 1.30/0.75 MPa. Stwierdzono, że wzrost koncentracji nicieni pojawił się jedynie w końcowej fazie opróżniania opryskiwacza.

EN

Effectiveness of hydraulic agitation system of wheelbarrow sprayer was investigated by measuring the concentration of the insectivorous nematodes Heterohabditis bacteriophora in water mixture. The measurements were done at mixing pressure: 0.30/0.15, 0.70/0.40 and 1.30/0.75 MPa. It was found that the increase of the nematodes concentration was observed only at a final phase of emptying of the sprayer tank.

13

Równomierność mieszania biologicznych środków ochrony roślin w zbiorniku opryskiwacza

Chojnacki J.

Inżynieria Rolnicza

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2008

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R. 12, nr 4(102)

163-167

PL

Badano efektywność mieszania biologicznych środków ochrony roślin w zbiorniku opryskiwacza polowego poprzez pomiary stężenia owadobójczych nicieni Steinernema feltiae. Badania wykonano przy ciśnieniach mieszania: 0,2; 0,4 i 0,6 MPa. Stwierdzono równomierną koncentrację nicieni w zbiorniku opryskiwacza w badanym zakresie ciśnień.

EN

We examined the effectiveness of mixing biological plant protection agents in a field sprayer tank by measuring the concentration of insecticidal nematodes Steinernema feltiae. The tests were performed at mixing pressures of 0.2, 0.4 and 0.6 MPa. For the investigated pressure range the concentration of the nematodes in the sprayer tank has been found uniform.

14

Śmiertelność nicieni w obiegu hydraulicznym opryskiwacza

Chojnacki J.

Inżynieria Rolnicza

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2007

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R. 11, nr 3 (91)

45-50

PL

Przeprowadzono badania nad zmianami śmiertelności względnej nicieni Steinernema feltiae - biologicznego środka ochrony roślin, pod wpływem wielokrotnego przepompowywania ich w instalacji opryskiwacza. Wartości ciśnienia cieczy z nicieniami przyjęto równe 0,6 i 1,2 MPa. Maksymalna ilość cykli całkowitego przepompowania cieczy znajdującej się w instalacji wyniosła 170. Stwierdzono wzrost śmiertelności nicieni wraz ze wzrostem ilości cykli.

EN

Mortality of nematodes in hydraulic cyrculation of sprayer The research which was carried out dealt with the turns of relative mortality of nematodes Steinernema feltiae - biological pest control means, by multiple pumping them in the installation of the sprayer. The values of the pressure of liquid in which nematode were contained equalled 0,6 and 1,2 MPa. The value of maximum quantity of cycles - periods of time in which liquid was totally pumped in the installation, was 170. It was observed that the increase of cycles brings about the increase of mortality of nematodes.

15

Rozkład poprzeczny biologicznego środka ochrony roślin

Chojnacki J., Jarmocik E.

Problemy Inżynierii Rolniczej

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2006

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R. 14, nr 4

13-20

PL

Przeprowadzono badania nad nierównomiernością rozkładu poprzecznego cieczy użytkowej zawierającej biologiczny środek ochrony roślin - owadożerne nicienie Steinernema feltiae, rozpylanej pod belką poruszającego się opryskiwacza polowego. Nie stwierdzono zależności pomiędzy nierównomiernością rozkładu poprzecznego nicieni a nierównomiernością rozkładu poprzecznego zawierającej je cieczy.

EN

The study dealt with transversal distribution of sprayed liquid with a biological plant protection agent based on the insectivorous nematodes Steinernema feltiae. The measurements were done under the spraying boom of running field sprayer. No relationship was found between distribution non-uniformity of the nematodes and distribution nonuniformity of sprayed liquid containing the nematodes.

16

Ocena przeżywalności biologicznych środków ochrony roślin: nicieni - Steinernema feltiae rozpraszanych za pomocą dyszy hydraulicznej

Chojnacki J.

Inżynieria Rolnicza

|

2006

|

R. 10, nr 13(88)

47-53

PL

Przeprowadzono badania nad wpływem rozmiaru otworu dysz, wartości ciśnienia i krotności przepływu na przeżywalność zawartych w cieczy nicieni Steinernema feltiae, które są biologicznym środkiem ochrony roślin. Badania symulowały proces mieszania. Aby uniknąć zakłóceń wyników spowodowanych pracą pompy opryskiwacza, której wpływ na przeżywalność nicieni nie był znany, do wytworzenia ciśnienia cieczy użyto sprężonego powietrza. Ciecz przepływała przez dysze 25, 50 i 75 krotnie. Średnice otworów miały rozmiar 0,8 i 1,2 mm a przyjęte ciśnienia równe były 0,6 i 1,2 MPa. Stwierdzono wpływ ciśnienia i krotności przepływu na przeżywalność nicieni.

EN

Tests of the effect of nozzle hole size, pressure value and flow multiplicity on survivalness of nematodes Steinernema feltiae contained in liquid, which are plant protection biological agent, were carried out. The tests were a simulation of mixing process. In order to avoid disturbances of the results caused by operation of the spraying machine pump, the influence of which on nematodes survivalness was not known, for generating liquid pressure compressed air was used. The liquid was flowing through the nozzles 25, 50 and 75 times. The diameters of the holes were 0,8 and 1,2 mm and the applied pressure was 0,6 and 1,2 MPa. Influence of pressure and flow multiplicity on nematodes survivalness was determined.

17

Wpływ jonów kadmu na przeżywalność IJs Steinernema feltiae w glebie i ich zdolność do infekowania żywiciela (Galleria mellonella L.)

Jarmuł J., Kamionek M., Pezowicz E.

Chemia i Inżynieria Ekologiczna

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2006

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Vol. 13, nr S1

157-162

PL

W warunkach laboratoryjnych do piasku dodano azotanu kadmu [Cd(NO3)2 . 4H20] o stężeniach 1,5, 10 ppm Cd. Stężenia te określają stopień skażenia gleb od I do 6, przyjęty przez IUNG. Doświadczenie to trwało 21 dni. Larwy inwazyjne S. feltiae zostały wypuszczone do skażonego piasku. Owad testowy (G. mellonella) został wprowadzony w czterech odstępach czasowych: bezpośrednio, po 7, 14 i 21 dniach od skażenia piasku i wprowadzeniu do niego IJs S. feltiae. Przeprowadzone badania wykazały, jaki jest wpływ czasu kontaktu IJs S. feltiae z kadmem w skażonym środowisku. Wpływ ten objawiał się zmianami w inwazyjności nicieni.

EN

In the laboratory experiment, cadmium nitrate [Cd(N03)2 . 4H20] was added to sand in concentrations of 1,5 and l0 ppm Cd. The concentrations refer to the 1st to 6th degree in the soil contamination classification adopted by the Institute of Crops, Fertilization and Soil Science, Puławy, Poland. The experiments lasted 21 days. Invasive łarvae of S. feltiae were released anto the contaminated sand. The test insect (G. melollella) was intro-duced on four dates: immediately and after 7, 14 and 21 days since sand contamination and the release of the IJs of S. feltiae. The studies demonstrated the effect of the contact limf of the IJs of S. feltiae with cadmium in contaminated sand manifesting itself in chan ges of the invasive properties of the nematodes.

18

Forest litter bacteria : relationships with fungi, microfauna, and litter composition over a winter-spring period

Krivtsov V., Liddell K., Bezginova T., Salmond R., Staines H. J., Watling R., Garside A., Thompson J. A., Griffiths B. S., Brendler A.

Polish Journal of Ecology

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2005

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Vol. 53, nr 3

383-394

EN

This paper presents data on temporal and spatial variability and ecological interactions of bacteria in a Scottish woodland over a winter-spring period (January-April). The study sites covered an area of 1 ha and a range of woodland habitats formed by beech (Fagus silvatica), birch (Betula pendula x pubescens) and oak (Quercus petraea), as well as (one site) a clearance site covered with grass (predominantly Holcus lanatus). Subsamples of fresh litter were fragmented for 60 s in a domestic food processor and were subsequently used to estimate the abundance of bacteria by counting under a fluorescent microscope. The preparation of bacterial slides involved staining with DTAF following extraction in phosphate buffer. The data on protozoa, fungi and microinvertebrates were available from parallel research and were obtained using standard methods. Numbers of bacteria appeared to be lower in sites dominated by beech. The highest average bacterial abundance (9.07x108 cells g-1 dry litter) was registered in January, and then gradually declined till March, when the lowest (7.37x108 cells g-1 dry litter) value was found, before rising again in April. The only significant difference revealed by one-way ANOVA was between January and March results. Both date and site effects were found to be significant by two-way ANOVA, but the date site . interaction was not significant. A number of significant relationships were registered by stepwise regression analysis, ANCOVA, and correlation analysis. In stepwise regression analysis, the most important predictor for bacterial density was litter moisture content (all months but March). Further significant relationships were revealed with the abundance of fungi, nematodes, and microarthropods, and forest litter fractions of moss, needles, beech seeds and birch leaves. ANCOVA confirmed the importance of interactions with litter composition and moisture content, and the abundance of fungi and microarthropods, and revealed a relationship with the abundance of ciliates. Correlation analysis for separate months revealed various relationships with forest litter composition (including positive . with forest litter fractions of oak leaves, grass, roots, birch leaves, and negative ones . with forest litter fractions of ferns and seeds), and the abundance of other microbiota, including positive with Folsomia candida (Insecta, Apterygota, Collembola), fungi, plant and microbial feeding nematodes, tardigrades and enchytraeids, positive and negative with ciliates, and negative with predatory nematodes. Most of these relationships, plus a further correlation with the abundance of amoebae, were also revealed for the combined dataset. It should be noted that some of these interactions (e.g. with % grass, % roots, the density of Folsomia candida) were only revealed by correlation analysis, and may therefore be judged as less important than relationships registered by all statistical methods applied. The results of this study highlighted the complexity of multivariate interactions of bacteria in forest litter.

19

The role of Lumbricus rubellus Hoffm. in determining biotic and abiotic properties of peat soils

Makulec G.

Polish Journal of Ecology

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2002

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Vol. 50, nr 3

301-339

EN

The field study was conducted on fifteen peat meadows located in the Biebrza river valley, north-eastern Poland, to estimate the range of changes in Lumbricidae communities with time after drainage. In a field experiment, the effects of L. rubellus were examined on the composition and abundance of microflora, Nematoda, Collembola, and Enchytraeidae, and on resources of exchangeable nutrients in drained peat soils. The occurrence of 2-6 earthworm species was noted in soils of drained peats. L. rubellus appeared already 3-5 years after drainage and rapidly reached high densities and biomass. It showed preference for moderately or heavily moorshed soils, with high contents of total nitrogen and phosphorus, low C/N, moderate porosity, and moderate moisture. Casts of this species contained more fungi and cellulolytic microorganisms, while less bacteria and actinomycetes, as compared with their contents in the soil. Also urease activity, content of fulvic acids and concentrations of exchangeable phosphorus, magnesium, and potassium were higher in casts. In a 4-month field experiment, different densities of L. rubellus were used: 2,4, and 6 individuals in 1.5 L isolators inserted to soil. The control variant was without earthworms. It was found that high L. rubellus densities in peat moorsh enhanced bacteria, ammonifying microorganisms, microorganisms utilising mineral nitrogen, and seasonally also actinomycetes and cellulolytic microbes. Also total microbial biomass, dehydrogenase activity, and the rate of cellulose decomposition were higher. The abundance of soil fungi noticeably decreased. Moreover, L. rubellus significantly influenced nemathode composition and abundance. Within a short time, their total numbers declined, especially numbers of bacterial-feeding nematodes. Also numbers an proportions of fungivorous nematodes slightly declined. Plat-feeding nematodes were least affected by this species, and in some periods their numbers were higher in the presence of earthworms than in the control. In the field experiment, no noticeable effect of earthworms was found on total enchytraeid numbers. In the period of autumn peak of Collembola, high numbers of L. rubellus reduced their densities. By modifying the composition and abundance of microflora, nemathodes and mesofauna high L. rubellus densities (above 200 individuals m^-2) can increase the rate of organic matter mineralization, intensify competition for nutrients, and indirectly they contribute to the biological decomposition of moorsh in soils of drained peat meadows.

20

A comparative study of the life strategies of two bacterial-feeding nematodes under laboratory conditions. 2, Influence of the initial food level on the population dynamics of Acrobeloides nanus (de Man 1880) Anderson 1968 and Dolichorhabditis dolichura

Ilieva-Makulec K.

Polish Journal of Ecology

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2001

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Vol. 49, nr 2

123-135

EN

Population dynamics of two bacterial-feeding nematodes Acrobeloides nanus and Dolichorhabditis dolichura in relation to the initial food level was studied under laboratory conditions. Population density, age structure and selected productivity parameters of the two nematodes were compared in single and mixed species cultures. Initial food (bacteria Sporosarcina sp.) level significantly affected population dynamics of A. nanus and D. dolichura in the laboratory cultures. While A. nanus grew well at the three food levels, D. dolichura developed only at the highest initial density of food. There were significant differences in population dynamics of both studied species at the highest initial density of the bacterial food. In single species cultures population peak of D. dolichura occured earlier than that of A. nanus and maximal density of D. dolichura was significantly higher than maximal density of A. nanus. In mixed cultures population maximum was observed at the same time in both species and their peak densities were similar. Population maximum of A. nanus in mixed cultures was observed earlier than in its single cultures but the peak density of that species in single cultures was significantly higher than in mixed ones. Population peak of D. dolichura at the highest food level occurred at the same time irrespective of the type of culture, while peak abundance of that species in mixed cultures was almost 50% lower than in single cultures. The differences observed in population dynamics of the two nematode species were discussed with respect to the differences in the food supply of their natural habitats and the role they play in the processes of decomposition and mineralisation in soil.