A method to increase the survival of probiotic bacteria Lactobacillus brevis at a lowered pH

Lactobacillus brevis PCM 2570 is a strain of lactic acid bacteria, i.e. probiotic bacteria whose major fermentation product is lactic acid. The efficiency of lactic acid production is limited by the value of ambient pH. This study aimed to increase the survival of this bacterial strain at a reduced pH (3.9), which would result in an increased yield of lactic acid fermentation. In our experiment the survival rate of probiotic bacteria L. brevis PCM 2570 was increased 1.2-fold to 6.96-fold due to the presence of Fe3O4 magnetic nanoparticles, as compared to the control. The minimum concentration of nanoparticles with a positive effect was 8 mg/ml, but the optimum concentration was 20 mg/ml.

Predation by invasive Platydemus manokwari flatworms: a laboratory study

Platydemus manokwari de Beauchamp, 1963 is an invasive flatworm found on islands in the tropics, especially in the Pacific Ocean. It has been implicated in the decline of several snail populations, including the extinction of some Partula species. Its predatory behaviour was investigated to quantify predation rates and elucidate climatic influences. This laboratory study of the invasive flatworm confirms earlier reports that P. manokwari is a generalist predator of snails. It prefers small prey and avoids species defended by copious mucus, chemical defences or a tough integument. Prey are found by following damp mucus trails up to 15 h old. Flatworm activity is limited by temperature and humidity, with peak feeding at 24–30°C and 85–95% humidity. This determines the geographical spread of the species and probably also the effectiveness of arboreal predation. Aboveground air circulation leads to drying, reducing the ability of the flatworms to locate trails and remain active high off the ground. Local climatic factors may dictate how significantly P. manokwari affects snail populations.

A search for 4 specific markers linked to Pm3 alleles for resistance to powdery mildew (Blumeria graminis) in rye (Secale cereale)

To investigate powdery mildew resistance in rye (Secale cereale), 397 inbred lines of winter rye were tested for susceptibility to infection with Blumeria graminis f. sp. secalis. The 50 most tolerant lines and 50 most infected lines were chosen for comparison. They were next tested for the presence of 4 markers linked to 4 alleles for resistance to powdery mildew, identified earlier in common wheat (Triticum aestivum). We found Pm3a only in 3 susceptible genotypes of winter rye, although this marker is linked to the powdery mildew resistance gene in wheat. The other 3 markers linked to Blumeria graminis f. sp. secalis resistance genes (Pm3b, Pm3c, Pm3d) were found in neither resistant nor susceptible rye genotypes.

Length-weight relationship and growth parameters of the commercial fish Pagellus erythrinus (Linnaeus, 1758) (Actinopterygii: Sparidae) from northern and southern Tunisia

Based on length, weight, and age data, we examined allometry and growth parameters for common pandora, Pagellus erythrinus, commercially collected seasonally from northern and southern Tunisian coasts in 2007. A total of 370 specimens (14–27.5 cm in length) were used to assess the allometric variation at seasonal scales. The slope b values (regression coefficient) of the length-weight relationship varied between 2.494 to 3.237, indicating (roughly) an isometric to negative allometric growth pattern. The allometric relationship, as a proxy for fish condition, seems to be affected by seasons and sex in the northern population, while only seasons seem to have a strong effect in the southern population, as indicated by ANOVA. The von Bertalanffy growth parameters were identified at L∞ = 34.076 and 28.017 cm, k = 0.153 and 0.150/year, and t0 = −1.922 and −3.961 years for the northern and southern sample, respectively.

In vitro interactions between Trichoderma harzianum and pathogenic fungi damaging horse-chestnut (Aesculus hippocastanum) leaves and fruits

Interactions between 3 pathogenic fungi damaging horse-chestnut (Aesculus hippocastanum) leaves and fruits – Phyllosticta sphaeropsoidea, Phomopsis carposchiza, and Diaporthe padi – and the antagonistic fungus Trichoderma harzianum were studied to determine their mutual influence in vitro. Antibiosis of colonies developing on 5 nutrient media was tested. The 3 studied T. harzianum isolates differed in their antagonistic potential. although T. harzianum isolates significantly inhibited the growth of Phomopsis carposchiza, the mycelium growth of some of the re-isolates on fresh medium indicates an inadequate antagonistic effect of T. harzianum on this species. The tested Trichoderma isolates showed stronger antagonism towards the other pathogens, reflected in overgrowing of Phyllosticta sphaeropso-idea and Diaporthe padi and reducing their growth. Granulation of the cytoplasm and lysis of hyphae of the fungal pathogens were the most frequently observed effects of the interaction.

Effects of green algae and napa cabbage on life-history parameters and gut microflora of Archegozetes longisetosus (Acari: Oribatida) under laboratory conditions

We compared the effect of green algae (dominated byProtococcussp.) and the earlier studied napa cabbage on the life-history parameters and gut microflora of the oribatid miteArchegozetes longisetosus(a chelicerate model organism). Napa cabbage contained more crude ash, protein, and crude fibre than green algae, butA.longisetosusdeveloped better on the latter food, displaying higher fertility, lower mortality of offspring and shorter development than on napa cabbage. The gut microflora ofA.longisetosusdepended on the kind of food and developmental stage of this mite. The adults fed with napa cabbage had more abundant and more active microflora than those fed with green algae, whereas in the tritonymphs the microflora was more abundant when they were fed with green algae, and was more active in the group fed with napa cabbage. Irrespective of the treatment, the highest percentage of the isolated bacteria were gram-positive bacilli or gram-negative bacteria, but the mites feeding onProtococcussp. contained no cocci, whereas those fed with cabbage had no gram-positive bacteria.

Cyst morphology of large branchiopod crustaceans (Anostraca, Notostraca, Laevicaudata, Spinicaudata) in western Poland

The morphology of resting eggs was studied in Polish populations of 7 large branchiopod species:Branchipus schaefferi,Chirocephalus shadini,Eubranchipus grubii(Anostraca),Lepidurus apus,Triops cancriformis(Notostraca),Lynceus brachyurus(Laevicaudata), andCyzicus tetracerus(Spinicaudata). Scanning electron microscope photographs for each species are also provided. In some species (especiallyE. grubii), the ornamentation and size of cysts from Polish populations significantly differ from literature data for populations from other parts of Europe. We also present a key to determination of the studied species based on cyst morphology and discuss whether those traits are useful in surveys of new localities of endangered large branchiopods.

Preliminary study of the impact of pig or goat manure fertilization of a meadow on oribatid mites

We investigated the impact of pig or goat manure fertilization of a meadow with doses of 80 kg N ha−1, 140 kg N ha−1, and 200 kg N ha−1(plots 1-6) on oribatid mites. A control plot (0) was left unfertilized. The manure was applied to the meadow in the early spring of 2012, and soil samples were collected in the spring of 2012 and 2013. In total, 6053 oribatid mites were examined, including 1163 juveniles. The effect of fertilizing on the Oribatida depended on the dose of manure, but not on its type. A low dose of pig or goat manure did not affect the density of Oribatida, whereas the other doses decreased it, but only the highest doses decreased it significantly, compared to the control. Species diversity decreased with the dose of manure. In total, 24 species of Oribatida were found and some species reacted differently to both types of manure. For example, a low dose of pig manure significantly increased the density ofEupelops occultus, whereas the density of other species significantly decreased under the influence of the highest dose of pig manure (Achipteria coleoptrata), highest doses of pig and goat manure (Galumna obvia,Liebstadia similis), and medium and highest doses of goat manure (Scheloribates laevigatus).

About the Greek origin of acarology: a short note on Argas and the Acari

The article presents the etymology and Greek roots of two terms in modern acarology. The origin of acarological nomenclature is analysed in the context of Homer’s Odyssey and Aristotle’s Parts of Animals and History of Animals. The Greek concept of the smallest animals “acari” as indivisible has been influencing European culture for centuries. The article shows the influence of the Greek tradition on zoology in the 18th century, at the time of birth of modern acarology. The works of French naturalists, the founders of this science, are analysed in this context.

Microhabitats and oribatid fauna: comparison of 2 sampling approaches

Oribatid fauna highly varies among habitats, but different microhabitats within a habitat are also characterized by different mite species. The main goal of the research was to compare the observed structure of an oribatid community when samples were collected at random from the soil-litter layer of 0-10 cm in depth (standard approach) and selectively from 6 types of available microhabitats (complex approach). Samples were taken within a small plot (10 m × 10 m) in a forested area of the Silesian Park (Chorzów, south Poland). Overall, 2642 specimens of Oribatida belonging to 62 species were collected in 66 samples. The structure of the oribatid community observed by means of the 2 sampling approaches was completely different. The abundance and species richness of oribatid mites collected from 6 microhabitats were significantly higher than in the soil-litter layer alone. Results of this study show that random collecting of only soil-litter samples may reduce the evaluation of species richness in a study area by 40%. Each of the studied microhabitats supported a peculiar oribatid fauna.