Janina Šyvokienė

Hydrocarbon-Degrading Bacteria in the Digestive Tract of Fish, their Abundance, Species Composition, and Activity

The abundance and species composition of the intestinal bacterioflora of perch, roach, gudgeon, and ruffe from the Curonian Lagoon as well as the activity of their eight bacterial strains in degrading oil hydrocarbons were investigated. The research showed the abundance of bacteria in the intestinal bacteriocenoses of different trophic fish groups investigated to vary with different fish species. With regard to morphological, physiological and biochemical features, isolates from fish intestinal bacteria able to degrade oil hydrocarbons belonged to the genera Aeromonas, Pseudomonas, Flavobacterium, and Micrococcus. Bacteria of the genus Aeromonas made 70% of the total abundance of hydrocarbon-degrading bacteria. It was established that oil hydrocarbons degrading bacteria of the species Aeromonas eucrenophila and Aeromonas media prevail in the digestive tract of the investigated fish. It was also determined that the activity of different bacterial strains in degrading diesel oil differs and varies within a ...

Acute Toxicity of Copper-Zinc Mixture to Rainbow Trout (Oncorhynchus mykiss) and its Impact on the Bacterial Flora of the Digestive Tract

Investigations were carried out on acute toxicity of copper-zinc mixture to rainbow trout (Oncorhynchus mykiss) and on the abundance of bacteria in the digestive tract. The data obtained showed that the exposure duration evidently influenced the value of median acutely lethal concentration (LC50). The greatest differences were observed between 24-hour and 96-hour values, while 72-hour and 96-hour values were quite close. The abundance of total heterotrophic and proteolytic bacteria was greatest in controls and lowest in high concentrations mixture exposure. The abundance of total heterotrophic bacteria in the digestive tract from highest-exposure fish were two orders of magnitude lower compared to control fish. In these experiments, the cultivable total coliform bacterial densities actually increased following the addition of toxicant, possibly as a result of the release of organic carbon from poisoned copper-zinc sensitive organisms.

Change in the Intestinal Microflora of Molluscs from the Neris River Depending on Pollution

A comparative study of the intestinal microflora of molluscs collected at four different stations on the Neris River was conducted. Populations of aerobic heterotrophic bacteria present in the digestive tract of molluscs were estimated using plate dilution technique. The data obtained showed that total heterotrophic bacteria dominated in the intestinal bacterial flora of molluscs. Proteolytic, amylolytic, hydrocarbon-degrading and total coliform bacteria, as separate physiological groups of heterotrophic bacteria, were abundant in the intestinal bacteriocenosis of molluscs. The viable counts of hydrocarbondegrading bacteria were revealed to vary between 3 × 104 – 3 × 105 g-1 of the intestinal contents. The greatest numbers of hydrocarbon degrading and total coliform bacteria were isolated from the molluscs collected from the Neris River upstream of and downstream of Jonava. Viable counts of different types of bacteria in the digestive tract of molluscs varied with mollusc species. The abundance and compos...

The impact of zinc on the bacterial abundance in the intestinal tract of rainbow trout ( Oncorhynchus mykiss ) larvae@@@Cinko poveikis bakterijų gausai vaivorykštinio upėtakio ( Oncorhynchus mykiss ) žarnyne

Th e paper presents an estimation the eff ect of zinc (0.13 mg/l, 0.5 mg/l, 2 mg/l and 8 mg/l in water) on the abundance of bacteria in the intestinal tract of rainbow trout (Oncorhynchus mykiss) larvae. Populations of total aerobic heterotrophic bacteria present in the intestinal tract of rainbow trout larvae, estimated using the dilution plate technique, were reduced signifi cantly in comparison with control aft er exposure to 0.5 mg/l, 2 mg/l and 8 mg/l of zinc. Th e abundance of total heterotrophic bacteria decreased most signifi cantly aft er exposure of larvae to 2 mg/l of zinc and was one order of magnitude lower in comparison with control. Th e same trend was observed for the abundance of proteolytic and total coliform bacteria in the intestinal tract of rainbow trout larvae aft er exposure of larvae to 2 mg/l of zinc. Zinc is toxic to bacteria in the intestinal tract of rainbow trout larvae, but at signifi cantly higher concentrations in comparison with copper ions.

The Effect of Heavy Metals on Microorganisms of Digestive Tract of Crayfish

The toxic effect of metal mixtures of five heavy metals (Cu, Zn, Ni, Cr, Fe) was investigated on microorganisms of the digestive tract of noble (Astacus astacus) and signal (Pacifastacus leniusculus) crayfish. The results obtained indicated that mixture of heavy metals have an injurious effect on the qualitative and quantitative composition of bacteriocenosis in the digestive tract of noble and signal crayfish towards the decrease of their numbers. Under the influence of the metal mixture the qualitative composition of the bacteriocenosis in the digestive tract of crayfish has undergone change and percentage ratio of starch-hydrolysing bacteria increased in the digestive tract of investigated crayfish. Proteolytic bacteria were most sensitive to the mixture of heavy metals.

HYDROCARBON-DEGRADING BACTERIA ASSOCIATED WITH INTESTINAL TRACT OF FISH FROM THE BALTIC SEA

Abstract The hydrocarbon-degrading bacterial diversity of the intestinal tract content of fish – the Baltic cod (Gadus morhua), plaice (Platichthys flesus) and the Baltic herring (Clupea harengus) – from the Baltic Sea has been investigated by molecular methods: DNA extraction, amplification polymerase chain reaction product and sequencing of partial 16S rRNA genes. The results of this study show that dense total heterotrophic bacterial populations occur in the intestinal tract of investigated fish. The data obtained showed that the abundance of hydrocarbon-degrading bacteria in the intestinal tract of fish varied from 2.40×104 to 1.08×105 cfu g–1 between fish species and was still high. Phenotypic examination of the recorded hydrocarbon-degrading bacteria from the intestinal tract of the Baltic cod, plaice and the Baltic herring revealed that they belong to Aeromonas, Pseudomonas/Shewanella. Molecular species of hydrocarbon-degrading bacteria found in the digestive tract of fish from the Baltic Sea were:...

Bioindication of the Ecotoxicity of the Nemunas River according to the Functional Changes in Bacteriocenoses of the Sediments and the Digestive Tract of Molluscs

Our studies revealed that hydrocarbon-degrading bacteria are found not only in water and sediments, but in the digestive tract of hydrobionts as well. Their abundance in the endosystem of hydrobionts is much higher than in the environment of the macrobionts. On the basis of functional changes in the bacteriocenoses of sediments and digestive tract of molluscs, we may state that the stretch of the Nemunas River near Merkinė is the safest locality for the populations of hydrobionts in comparison to other stretches of the Nemunas River. In this stretch of the Nemunas River, the abundance of hydrocarbon-degrading bacteria in sediments and the digestive tract of hydrobionts was the lowest. In other stretches of the Nemunas River (near Liskiava, Kulautuva, Rusnė and in Kaunas reservoir near Kapitoniskės), the number of hydrocarbon-degrading and intestinal bacteria in the bacteriocenoses of the digestive tract of hydrobionts and in sediments was high. That means the ecosystem of the river near those localities i...

Impact of copper and zinc mixture on bacterial flora of digestive tract of rainbow trout (oncorhynchus mykiss)

AbstractThe effects of 96-hour exposure and within 12 days after exposure to 0.25, 0.125, 0.06 portions of the 96-hour LC50 of CuZn ions mixture on microbiological parameters of rainbow trout digestive tract were studied evaluating quantitative and functional characteristics of bacteria. The extinction of proteolytic bacteria was found in fish affected by 0.25 portion of the 96-hour LC50 of metal mixture. The recovery of proteolytic bacteria was determined in fish exposed to 0.125 and 0.06 portions of the 96-hour LC50 of CuZn ions mixture after 8 days of keeping fish in clean water. The abundance of the investigated functional groups of bacteria was gradually recovering to the control level after 12 days of keeping fish in clean water.