Heavy metals adversely influence microorganisms, affecting their growth, abundance, genetic diversity, nodulation ability and efficacy. The aim of this study was to isolate and characterize free-leaving Rhizobium from soil which were artificially polluted with Cu (100, 250, and 500 mg kg-1 soil), Zn (300, 700, and 1500 mg kg-1 soil) and Pb (50, 250, and 1000 mg kg-1 soil), but also with a mixture of all these metals, and cultivated with red clover (Trifolium pratense L.), and to compare them with bacteria isolated from similar type of soil, but unpolluted. Rhizobia from soil were isolated on YMA medium with or without bromothymol blue (0.00125%) as a pH-change indicator and the morpho-physiological characteristics of the colonies were examined. The number of Rhizobium was estimated using the most probable number method. Compared to the control, a decrease of rhizobia number and an increase of the metal concentration were observed. Several decameric primers (Operon Technology type) were used and a reduced polymorphism among isolated bacteria was observed. Moreover, significant differences were observed among these strains and the collection strains used as reference. Also, when primers nodCF/nodCI for detection of nod genes were used, several amplicons were obtained, different from the results obtained with similar strains isolated from unpolluted soil. These results suggest that the survival „price” of the Rhizobium in such polluted area was the alteration of some genes, including those involved in symbiosis and, probably, in nitrogen fixation.

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Plant health is one of the issues that have to be maintained and closely monitored during cultivation and harvest. In this regard, prevention is the key factor in organic production. Biological control of plant pathogens and plant growth stimulation can be done through beneficial microorganisms. Different bacterial bio-preparates are available on the market, many of them based on selected strains of Bacillus species. In our previous studies, we isolated autochthones strains of Bacillus spp. with beneficial traits for plant protection and growth promotion. Considering the interest for biological production, and public concern for healthy products without significantly reduced yield, different biological control strains of Bacillus spp. that could be used as bio-inoculants for plant protection were analyzed.Thirteen biocontrol strains of Bacillus spp. were analyzed in comparison with three referent strains of B.subtilis and B.licheniformis. Qualitative and semi-quantitative analysis of these biocontrol Bacillus spp. strains was studied in order to characterize their enzymatic activity with implications either in cell wall degradation of plant pathogenic microorganisms, or in metabolism of various substrates. Genetic variability was studied by rep-PCR analysis compared with reference strains of B.subtilis and B.licheniformis. Microbiological studies performed in order to characterize the selected beneficial bacteria for their ability to produce lytic enzyme involved in plant pathogenic inhibition and plant growth stimulation revealed chitinase, cellulose, protease, lipase, amylase, decarboxylase, ACC-deaminase and phosphatease activity. The molecular techniques revealed significant genetic differences among the bacterial strains analyzed. The study allowed the detection of several enzymatic mechanisms involved in plant growth and protection, and revealed the potential of autochthon microbiota to be used for biotechnological purposes.

Among fruit plants belonging to the Rosaceae family, medlar (Mespilus) can be classified as neglected or underutilized. It is a genus of two species of flowering plants: Mespilus germanica (common medlar) and Mespilus canescens. Appreciated for its specific taste and flavor, medlar also possesses biological properties (antioxidant and antimicrobial). Despite the special properties of medlar, there are few research papers on this subject. This review paper includes data not only on medlar fruits but also its leaves, bark, and bud flowers. The main identified components are presented, as well as several biological properties, morphological properties, ethnopharmacological uses, and molecular biology analyses emerging from the scientific papers published in this area.

In this study, three types of extracts isolated from leaves of Plantain (Plantago lanceolata) were tested for their chemical content and biological activities. The three bioproducts are combinations of polysaccharides and polyphenols (flavonoids and iridoidic compounds), and they were tested for antioxidant, antifungal, antitumor, and prebiotic activity (particularly for polysaccharides fraction). Briefly, the iridoid-enriched fraction has revealed a pro-oxidant activity, while the flavonoid-enriched fraction had a high antioxidant potency; the polysaccharide fraction also indicated a pro-oxidant activity, explained by the co-presence of iridoid glycosides. All three bioproducts demonstrated moderate antifungal effects against Aspergillus sp., Penicillium sp., and dermatophytes, too. Studies in vitro proved inhibitory activity of the three fractions on the leukemic tumor cell line THP-1, the main mechanism being apoptosis stimulation, while the polysaccharide fraction indicated a clear prebiotic activity, in the concentration range between 1 and 1000 µg/mL, evaluated as higher than that of the reference products used, inulin and dextrose, respectively.