Volume 7, Issue 3

The term ‘Rhizobium-legume symbiosis’ refers to numerous plant-bacterial interrelationships. Typically, from an evolutionary perspective, these symbioses can be considered as species-to-species interactions, however, such plant-bacterial symbiosis may also be viewed as a low-scale environmental interplay between individual plants and the local microbial population. Rhizobium-legume interactions are therefore highly important in terms of microbial diversity and environmental adaptation thereby shaping the evolution of plant-bacterial symbiotic systems. Herein, the mechanisms underlying and modulating the diversity of rhizobial populations are presented. The roles of several factors impacting successful persistence of strains in rhizobial populations are discussed, shedding light on the complexity of rhizobial-legume interactions.

Secondary metabolites obtained from Actinomycetales provide a potential source of many novel compounds with antibacterial, antitumour, antifungal, antiviral, antiparasitic and other properties. The majority of these compounds are widely used as medicines for combating multidrug-resistant Gram-positive and Gram-negative bacterial strains. Members of the genus Streptomyces are profile producers of previously-known secondary metabolites. Actinomycetes have been isolated from terrestrial soils, from the rhizospheres of plant roots, and recently from marine sediments. This review demonstrates the diversity of secondary metabolites produced by actinomycete strains with respect to their chemical structure, biological activity and origin. On the basis of this diversity, this review concludes that the discovery of new bioactive compounds will continue to pose a great challenge for scientists.

Desipramine is a widely used antidepressive agent that inhibits the reuptake of noradrenaline and serotonin, and central stimulants such as caffeine and amphetamine help to release noradrenaline and serotonin. This work aimed to evaluate whether the combination of these agents could produce a stronger antidepressant-like effect than either of the drugs alone. To this end, male mice were treated with different doses of desipramine, caffeine, amphetamine, desipramine-caffeine and desipramine-amphetamine. The results showed that all drugs produced decreased immobility time in the forced swimming model. The combined treatment of desipramine (0.31, 1.0 or 3.1 mg/kg i.p.) with caffeine or amphetamine (0.31 or 1 mg/kg i.p.) reduced immobility time greater than either of those drugs alone. The combined treatment of desipramine (0.31, 1 and 3.1 mg/kg i.p.) with amphetamine or caffeine (0.1 and 1 mg/kg i.p.) did not increase the motor activity significantly compared to the control. These results also suggested that drugs which promote the release of noradrenaline and serotonin could increase antidepressant-like effect of desipramine.

Increased proliferation activity in the central canal ependyma of adult rodent spinal cord was described after injury and is thought to participate in recovery processes. Proliferation activity is scarce under physiological conditions, but still could be of importance, as in vitro studies showed that the spinal cord ependyma is an internal source of neural stem cells. Data from these studies indicate that there are regional differences in the distribution of proliferation activity along the rostro-caudal axis. We analyzed the proliferation activities in the ependyma within the entire extent of intact adult rat spinal cord. To identify proliferating cells we performed immunohistochemistry either for cell cycle S-phase marker BrdU or for the nuclear protein Ki-67. BrdU and Ki-67 positive cells were counted on sections selected from four spinal cord regions — cervical, thoracic, lumbar and sacral/coccygeal. Analysis showed that the number of BrdU positive cells within the ependyma was very low in all subdivisions of the spinal cord. Both BrdU and Ki-67 labeling revealed a significantly higher number of proliferating cells in the ependyma of sacrococcygeal part in comparison to all other spinal cord regions, suggesting that the caudal spinal cord might have potentially higher regeneration capacity compared to more rostral parts.

Morphine, as well as opioid peptides, are well-known powerful analgesics. In addition to their use in the treatment of pain, opioids appear to be important in the growth regulation of neoplastic tissue. However, little is known on the influence of opioid peptides on apoptosis modulation in cancer cells. In the present study, we evaluated the effect of the µ-opioid receptor (MOR)-selective peptide, morphiceptin and its two synthetic analogs, on mRNA expression and protein levels of some crucial factors involved in apoptosis in three human cancer cell lines: MCF-7, HT-29, and SH-SY5Y. Using real-time PCR and ELISA assays, we have shown that the selected opioid peptides enhanced apoptosis of cancer cells by increasing the expression of pro-apoptoticc Bax and caspase-3, and decreasing expression of anti-apoptotic Bcl-2. Additionally, flow cytometry analysis performed on MCF-7 cells treated with annexin V/propidium iodide confirmed that the tested opioid peptides induced apoptosis in cancer cells. However, induction of apoptosis was not reversed by the opioid antagonist, naloxone, which suggests that this process is not mediated by the opioid receptors.

The association of cholesteryl ester transfer protein (CETP) and apolipoprotein E (APOE) gene polymorphisms with mild cognitive impairment (MCI) is under debate. Our aim was to evaluate the relationship between APOE and CETP genotypes with healthy ageing. We analysed 267 elderly subjects (55 to 80+ years), 163 with MCI and 104 healthy, and 50 healthy control subjects (35 to 55 years) from a Romanian population. Biochemical parameters and thyroid hormones were assayed in plasma. APOE and CETP TaqIB gene polymorphisms were determined. Elderly subjects had higher frequency of ɛ3/ɛ2 genotype (14.6% vs. 4%, P<0.001) than controls. Elderly subjects with MCI had lower high density lipoproteins (HDL) cholesterol (P=0.031), apoA-I (P=0.018), T3 (P=0.002), T4 (P=0.028) and TSH (P=0.001) hormone levels, higher systolic blood pressure (P=0.005), lower frequency of CETP B2 allele than the age-matched subjects. Healthy elderly subjects had CETP B2 allele associated with higher plasma apoA-I (P=0.021), lower circulating collagen (P=0.001) levels, and an increased frequency of the combined APOE ɛ2- CETP B2 genotype (18.3%) relative to MCI elderly subjects (7.6%, P=0.011). Healthy elderly subjects are characterized by higher HDL cholesterol, apoA-I levels and higher frequency of the combined APOE ɛ2 and CETP B2 alleles, indicating this pattern as representative for healthy ageing.

Aim of the study: The purpose of this study was to find out the relationship between the phase of infection (acute or persistent) and the ability of quantitative PCR to detect DNA of Toxoplasma gondii in circulating leukocytes in blood. Methodology: Animal serum samples were examined (50 sheep, 47 dogs, 32 dairy cows, 91 wild boars and 36 rabbits) for the occurrence of IgM and IgG antibodies to T. gondii by ELISA. Uncoagulated blood samples from the same animals were examined for the detection of T. gondii DNA in circulating leukocytes by real-time PCR. Results: Only IgM antibodies, characteristic for acute infection, were detected in 45 of the 256 serum samples (17.6%). Only IgG antibodies, corresponding with chronic infection, were detected in 120 of the 256 samples (46.8%). In 91 of the 256 samples (35.5%) neither IgM or IgG were detected by ELISA. For real-time PCR, animals were divided into three groups based on the serological results: (group I — acute infection, group II — chronic infection, and group III — no infection). In group I, the presence of T. gondii DNA was detected in 9 out of 45 samples (20%), whereas in group II only 1 of 120 samples was positive for T. gondii DNA (0.8%). In group III, no DNA of T. gondii (0/91 samples) was detected by real-time PCR. Significance: The proof of DNA by real-time PCR in IgM positive samples was statistically significant in comparison to IgG positive samples (P<0.0001).

There is a current trend to support pet health through the addition of natural supplements to their diet, taking into account the high incidence of medical conditions related to their immune system and gastrointestinal tract. This study investigates effects of the plant Eleutherococcus senticosus as a dietary additive on faecal microbiota, faecal characteristics, blood serum biochemistry and selected parameters of cellular immunity in healthy dogs. A combination of the plant with the canine-derived probiotic strain Lactobacillus fermentum CCM 7421 was also evaluated. Thirty-two dogs were devided into 4 treatment groups; receiving no additive (control), dry root extract of E. senticosus (8 mg/kg of body weight), probiotic strain (108 CFU/mL, 0.1 mL/kg bw) and the combination of both additives. The trial lasted 49 days with 14 days supplementation period. Results confirm no antimicrobial effect of the plant on the probiotic abundance either in vitro (cultivation test) or in vivo. The numbers of clostridia, lactic acid bacteria and Gram-negative bacteria as well as the concentration of serum total protein, triglyceride, glucose and aspartate aminotransferase were significantly altered according to the treatment group. Leukocyte phagocytosis was significantly stimulated by the addition of probiotic while application of plant alone led to a significant decrease.

Age and growth of the invasive population of round goby Neogobius melanostomus from the Slovak stretch of River Danube was examined. The samples (n=1130) were collected soon after the invasion was recorded (2004–2005), and later, when the population was already established (2008–2010). Invasive round goby in newly-occupied areas were found to reach smaller body size (15–153 mm standard length) compared to native populations. Age from 0+ to 4+, determined from scales, was recorded in both sexes. Annulus formed in April–May, which varied with age. Growth of freshly established gobies was negative allometric, suggesting increased allocation of their sources to reproduction, which corresponds to less specialized life-history. However, positive allometric growth found in longer established individuals suggests a shift in allocation towards somatic growth, which corresponds to more specialized life-history typical for native populations. None of the three parameters predicted by the theory of alternative ontogenies and invasive potential met the expectations, though two parameters, i.e. growth rate and age at maturation remain equivocal. This can be explained by too short of a time span that has elapsed from the beginning of invasion, or by ecological disturbances that have broken up otherwise stable environment in the habitat studied.

A study was conducted to measure the normal ranges, seasonal and annual variations in haematological and immune parameters of juvenile healthy Puntius sarana (weighing 75–100 g) during three major seasons over two consecutive years. Significantly (P<0.05) lower serum myeloperoxidase and ceruloplasmin activities, superoxide production, plasma glucose level, packed cell volume and haemoglobin concentration were detected in winter as compared to the summer season. However, serum lysozyme activity, antiprotease activity, total erythrocyte count (TEC) and TLC profiles were consistent during all seasons. The reference intervals (25th–75th) of each parameter were estimated and a range was established. The annual changes in immune parameters with minimum and maximum values were measured and a significant variation was noticed in myeloperoxidase, antiprotease, total protein levels and TEC over two consecutive years. The lower levels in haematological and innate immune status of fish during winter possibly indicate a higher disease risk period for the species.

The goal of this paper was to explain variability of phytoplankton in a shallow coastal area in relation to physico-chemical parameters. Temporal variability and composition of phytoplankton were investigated in the Kotor Bay, a small bay located in the south-eastern part of the Adriatic Sea. Samplings were performed weekly from February 2008 to January 2009 at one station in the inner part of the Kotor Bay, at five depths (0 m, 2 m, 5 m, 10 m, 15 m). Phosphates, nitrites and nitrates ranged from values under the level of detection to the maximum values of 1.54, 1.53 and 23.91 µmol l−1, respectively. The phytoplankton biomass — represented by chlorophyll a concentration — ranged from 0.12 to 6.78 mg m−3, reaching a maximum in summer. Diatoms were present throughout the whole sampling period, reaching the highest abundance in March (3.42×105 cells l−1at surface). The peak of dinoflagellates in July (2.2×106 cells l−1 at surface) was due to a single species, Prorocentrum micans. The toxic dinoflagellate Dinophysis fortii occurred at a concentration of 2140 cells l−1 in May. The present results of phytoplankton assemblages and distribution provide valuable information for this part of the south-eastern Adriatic Sea where data is currently absent.

Elements of the biology and ecology of A. robiniae were studied in Poland during the period of 2008–2009. The term of spring hatching, number of generations per season, developmental time of particular generations, lifespan of specimens and fecundity of particular generations were all defined. The dynamics of the species’ occurrence on its host plant were also determined. The two-year study showed a maximum of 11 aphid generations can develop on Robinia pseudoacacia. Females of the second and third generations were found to be the most fertile. These findings indicate that the species has adapted well in Poland and its biological predispositions have enabled it to rapidly increase in population.

South-western Poland belongs to the key staging areas for geese in Europe, supporting some 100000 birds in recent years. We compared goose counts conducted in the 1970s, 1990s and during 2009–2011 in this region, and linked the findings to the recent assessments of trends in the flyway-populations. Numbers increased several dozen times between the first two counts and have stabilized to the present. More than 14% of the flyway Tundra Bean Goose (Anser fabalis rossicus) stopped over in SW Poland on passage. Smaller numbers of White-fronted Goose (A. albifrons), Greylag Goose (A. anser), and four other rarer species, have all increased since the 1970s. The likely factors responsible for these changes are mild weather conditions, increased availability of large water bodies and shifts in winter ranges of particular species. Temporal mismatch between SW Poland and the total flyways in Bean and White-fronted Geese was recorded when we compared the long-term and the short-term population trends. Increasing reports of other species in SW Poland match the general tendencies in Europe. These data document that regional trends are not a simple reflection of those in flyways as a whole. To understand changes in goose populations a re-established international count network is desired.

Perezone, a sesquiterpenic benzoquinone with diverse medicinal properties, accumulates in the roots of Acourtia species. In this time-dependent study, the production of perezone was followed in A. cordata culture systems of plants kept in vitro or acclimated and grown in pots. Perezone was characterized by several analytical methods, using the crystallized compound isolated from roots of wild plants as standard. A procedure was developed for its selective quantification, which considers the specific bathochromic shift of the absorbance band in the visible region between the spectra of perezone in its non-ionic and ionic forms, with intensity directly proportional to concentration. In vitro, perezone was recovered from A. cordata roots in average amounts of 5.21 mg g−1 dry weight. Contrastingly, in plants under ex vitro conditions, perezone in roots increased logarithmically, rising from an average of 2.4 mg g−1 dry weight at the 12th week, to 43.6 mg g−1 dry weight at the 31st week, an amount comparable to wild plants. These findings show the feasibility of in vitro and ex vitro culture systems to propagate and conserve the germplasm of perezone-producing Acourtia plants, and a fast and reliable method for the quantification of this valuable compound.

The contents of cadmium, iron, lead and zinc in the biomass of two species of leafy vegetables after urban particulate matter (PM) application was investigated in lettuce (Lactuca sativa var. capitata) and chard (Beta vulgaris var. cicla). The experimental design consisted of four variables: i) two different soil types, ii) two vegetables, iii) two size fractions of contaminated particulate matter (PM) (0.063–0.119 mm, and <0.063 mm), and iv) foliar and soil application of the PM. The aliquots of the PM samples were applied to the soil before the experiment and as a foliar suspension during plant growth. The element uptake by plant biomass was significantly higher via foliar application, simulating the atmospheric deposition, than via the roots from the soil application treatment. The content in plants increased rapidly compared to the control treatment for the elements iron, lead and zinc. Gently washing the leaves only slightly reduced the amounts of Fe and Zn. However, the majority of Pb was removed by washing with the concentration dropping from 3000% to 500%. The effect of PM application on Cd contents in plant leaves was negligible, in most cases. Lettuce exhibited higher element uptake compared to chard. No adverse effects of PM application on growth parameters of the vegetables were observed. No significant differences were reported for particle size fractions of PM. Fluvisol soils had a higher element uptake via roots than Chernozem soils. Moreover, the addition of PM into the Fluvisol altered the sorption properties of the soil resulting in a lower Cd uptake by plants growing in PM amended Fluvisols.

Early chemical-induced stress in Solanum tuberosum leaves was visualized using delayed fluorescence (DF) imaging. The ability to detect spatially heterogeneous responses of plant leaves exposed to several toxicants using delayed fluorescence was compared to prompt fluorescence (PF) imaging and the standard maximum fluorescence yield of PSII measurements (Fv/Fm). The toxicants used in the study were two photosynthesis inhibitors (herbicides), 100 µM methyl viologen (MV) and 140 µM diuron (DCMU), and two heavy metals, 100 µM cadmium and 100 µM copper. The exposure times were 5 and 72 h. Significant photosynthesis-inhibitor effects were already visualized after 5 h. In addition, a significant reduction in the DF/PF index was measured in DCMU- and MV-treated leaves after 5 h. In contrast, only DCMU-treated leaves exhibited a significant decrease in Fv/Fm after 5 h. All treatments resulted in a significant decrease in the DF/PF parameter after 72 h of exposure, when only MV and Cd treatment resulted in visible symptoms. Our study highlights the power of delayed fluorescence imaging. Abundant quantifiable spatial information was obtained with the instrumental setup. Delayed fluorescence imaging has been confirmed as a very responsive and useful technique for detecting stress induced by photosynthesis inhibitors or heavy metals.

Total polyphenols, tannins, β-sitosterol, and bitterness values were determined in native and cultivated populations of Teucrium L. species from Croatia (T. arduini L., T. botrys L., T. chamaedrys L., T. flavum L., T. montanum L., T. polium L., and T. scordium L. subsp. scordioides Schreb.). Teucrium species have long been present in folk medicine for diverse medicinal uses, but little is known about polyphenols, phytosterols, and bitter principles. Spectrophotometrically determined contents of total polyphenols (TP) and tannins (T) significantly varied among investigated Teucrium species and were somewhat higher in native populations. The highest TP and T contents were measured in native specimens of T. montanum (TP: 13.68%; T: 3.48%). Scanning densitometry was used for measurements of β-sitosterol levels in plant samples ranged from 0.056% (T. montanum) to 0.129% (T. botrys), and it was not significantly different between native and cultivated specimens of the same plant species. Bitterness values were similar for native and cultivated samples of the same plant species; the highest was measured for T. montanum (15659). The present study suggests that Teucrium species growing in Croatia have potential for cultivation and might be a valuable source of natural bioactive compounds.

Significant root growth inhibition was observed during the very short 5 minute exposure time of barley roots to the low 10 μM concentration of cadmium. In addition to the cadmium-induced root growth inhibition, considerable radial expansion of roots was observed as a characteristic symptom of transient short-term exposure of roots to cadmium. The cadmium-induced radial expansion of roots was observed mainly the cortical cells of elongation zone that were twice as large as in control roots. Similarly as in cadmium-treated roots, short-term treatment with ACC significantly inhibited root growth and caused a marked radial expansion of cortical cells. The ethylene synthesis inhibitor cobalt significantly alleviated both the cadmium- and ethylene precursor-induced root growth inhibition and radial root expansion. The results indicate that ethylene probably plays a crucial role in the short-term cadmium-induced inhibition of root growth and radial cell expansion of barley root tips, which are the very early symptoms of cadmium toxicity.

The aim of the present study was to examine the antioxidant activity of three Veronica species (Plantaginaceae). The antioxidant potential of various extracts obtained from aerial flowering parts was evaluated by DPPH-free (1,1-diphenyl-2-picrylhydrazyl-free) radical scavenging activity and ferric-reducing antioxidant power assays. Considerable antioxidant activity was observed in the plant samples (FRAP values ranged from 0.97 to 4.85 mmol Fe2+/g, and DPPH IC50 values from 12.58 to 66.34 µg/ml); however, these levels were lower than the activity of the control compound butylated hydroxytoluene (BHT) (FRAP: 10.58 mmol Fe2+/g; DPPH IC50: 9.57 µg/ml). Also, the in vivo antioxidant effects were evaluated in several hepatic antioxidant systems in rats (activities of glutathione peroxidase, glutathione reductase, peroxidase, catalase, xanthine oxidase, glutathione content and level of thiobarbituric acid reactive substances) after treatment with different Veronica extracts, or in combination with carbon tetrachloride (CCl4). Pretreatment with 100 mg/kg b.w. of Veronica extracts inhibited CCl4-induced liver injury by decreasing TBA-RS level, increasing GSH content, and bringing the activities of CAT and Px to control levels. The present study suggests that the extracts analyzed could protect the liver cells from CCl4-induced liver damage by their antioxidative effect on hepatocytes.