Structural and functional comparison of Saccharomonospora azurea strains in terms of primycin producing ability.

Emerging and re-emerging microbial pathogens, together with their rapid evolution and adaptation against antibiotics, highlight the importance not only of screening for new antimicrobial agents, but also for deepening knowledge about existing antibiotics. Primycin is a large 36-membered non-polyene macrolide lactone exclusively produced by Saccharomonospora azurea. This study provides information about strain dependent primycin production ability in conjunction with the structural, functional and comparative genomic examinations. Comparison of high- and low-primycin producer strains, transcriptomic analysis identified a total of 686 differentially expressed genes (DEGs), classified into diverse Cluster of Orthologous Groups. Among them, genes related to fatty acid synthesis, self-resistance, regulation of secondary metabolism and agmatinase encoding gene responsible for catalyze conversion between guanidino/amino forms of primycin were discussed. Based on in silico data mining methods, we were able to identify DEGs whose altered expression provide a good starting point for the optimization of fermentation processes, in order to perform targeted strain improvement and rational drug design.

New insight into the Delia platura Meigen caused alteration in nutrient content of soybean (Glycine max L. Merill).

Climate change has brought about an increasing level of seedcorn maggot (Delia platura Meigen, 1826) (Diptera: Anthomyiidae) damage in Hungary. In order to have a more accurate understanding of the effects of these plant injuries induced by the larvae of D. platura, the nutrient content of soybean (Glycine max L. Merill.) was studied. Our results show that the moisture, raw fat, raw fibre, and raw ash content of the batches damaged by D. platura were significantly less in comparison with that of the control samples. In response to the deleterious effect of the insect, the infected soybean plants showed forced ripening (P = 0.004) (P > 0.05). The difference of moisture content between damaged and control samples was 2.30% on average. The fact of nutritional value loss was also reflected by the alteration of sugar mobilisation. As the result of this experiment the sucrose breakdown to glucose and fructose during the germination was significantly slower in the damaged seeds than that of the control ones. Overall, this late and surprising damage caused by D. platura led to the forced ripening of the affected soybean plants and a significant change in their nutritional values. Based on the herein reported results, it is presumable that in cases when the current climatic extremities, which are envisaged to occur more frequently in the future, and effects of agricultural practices will be coincided in the future a qualitative change of the produced soybean batches can be expected through the damage caused by this fly species.

Proteomic insight into the primycin fermentation process of Saccharomonospora azurea.

Saccharomonospora azurea SZMC 14600 is a member of the family Pseudonocardiaceae exclusively used for industrial scale production of primycin a large 36-membered non-polyene macrolide lactone antibiotic belonging to the polyketide class of natural products. Even though maximum antibiotic yield has been achieved by empirically optimized two-step fermentation process, little is known about the molecular components and mechanisms underlying the efficient antibiotic production. In order to identify differentially expressed proteins (DEPs) between the pre- and main-fermentation stages of primycin, comparative 2D-PAGE experiments were performed. In total, 98 DEP spots were reproducibly detected, out of which four spots were excised from gels, and identified through MALDI-TOF/TOF mass spectrometry. Peptide mass fingerprint analysis revealed peptide matches to HicB antitoxin for the HicAB toxin-antitoxin system (EHK86651), to a nucleoside diphosphate kinase regulator ((Ndk; EHK81899) and two other proteins with unknown function (EHK88946 and EHK86777).

Draft genome sequence of an efficient antibiotic-producing industrial strain of Saccharomonospora azurea, SZMC 14600.

Although certain rare actinomycetes have been recognized as prolific sources of bioactive natural products, their potential for producing biologically active metabolites still remains unexplored. With the aim of gaining global insights into the genetic background and the metabolic capability of Saccharomonospora azurea SZMC 14600, whole-genome sequencing was performed.

Comparison of blood and saliva lactate level after maximum intensity exercise.

Several studies have described high correlation of salivary and blood lactate level during exercise. Measuring the effectiveness and intensity of training, lactate concentration in blood, and lately in saliva are used.The aim of our study was to evaluate the correlation between the concentration and timing of salivary and blood lactate level in endurance athletes and non-athletes after a maximal treadmill test, and to identify physiological and biochemical factors affecting these lactate levels.Sixteen volunteers (8 athletes and 8 non-athletes) performed maximal intensity (Astrand) treadmill test. Anthropometric characteristics, body composition and physiological parameters (heart rate, RR-variability) were measured in both studied groups. Blood and whole saliva samples were collected before and 1, 4, 8, 12, 15, 20 min after the exercise test. Lactate level changes were monitored in the two groups and two lactate peaks were registered at different timeperiods in athletes. We found significant correlation between several measured parameters (salivary lactate - total body water, salivary lactate - RR-variability, maximal salivary lactate - maximal heart rate during exercise, salivary- and blood lactate -1 min after exercise test). Stronger correlation was noted between salivary lactate and blood lactate in athletes, than in controls.

Genetic analysis of the rkp-3 gene region in Sinorhizobium meliloti 41: rkpY directs capsular polysaccharide synthesis to KR5 antigen production.

Rhizobial surface polysaccharides, including capsular polysaccharides (KPS), are involved in symbiotic infection. The rkp-3 locus of Sinorhizobium meliloti 41 is responsible for the production of pseudaminic acid, one of the components of the KR5 antigen, a strain-specific KPS. We have extended the sequence determination and genetic dissection of the rkp-3 region to clarify the structure and function of the rkpY gene and to identify additional rkp genes. Except for rkpY, no other genes were found where mutation affected the KPS structure and symbiosis. These mutants show a unique phenotype producing a low molecular weight polysaccharide (LMW PS). Creating double mutants, we have shown that biosynthesis genes of the KR5 antigen except rkpZ are not necessary for the production of this LMW PS. Polysaccharide analysis of genetically modified strains suggests that rkpY has pleiotropic effects on polysaccharide production. It directs KPS synthesis to the KR5 antigen and influences lipo-oligo 3-deoxy-d-manno-2 octulosonic acid (Kdo) production in S. meliloti 41. In addition, rkpY suppresses the lipo-oligoKdo production when it is introduced into S. meliloti 1021.

Cold acclimation and abscisic acid induced alterations in carbohydrate content in calli of wheat genotypes differing in frost tolerance.

The effect of cold and abscisic acid (ABA) treatment on soluble carbohydrate content was compared in callus cultures of wheat genotypes differing in frost tolerance. The effect of 5A chromosome substituted from the frost tolerant <> to the sensitive <> on cold-induced carbohydrate accumulation was also determined. Following cold hardening, the increase in sucrose and fructan level in calli of tolerant varieties was significantly higher than those of the sensitive ones. In 5A substitution line higher sucrose and fructan content was detected than in recipient <>. Tendentiously, cold stress caused higher degree of changes in carbohydrate content than the exogenously applied ABA did. Comparing the accumulation pattern of the components of WSC measured in vitro to the previously published in vivo results it can be concluded that in the case of sucrose and fructans it was similar, while for the reducing sugars it was different. The regulatory role of chromosome 5A either in the development of freezing tolerance or carbohydrate accumulation was confirmed in dedifferentiated calli, as well.

The rice Osmyb4 gene enhances tolerance to frost and improves germination under unfavourable conditions in transgenic barley plants.

The Osmyb4 rice gene, coding for a transcription factor, proved to be efficient against different abiotic stresses as a trans(cis)gene in several plant species, although the effectiveness was dependent on the host genomic background. Eight barley transgenic lines carrying the rice Osmyb4 gene under the control of the Arabidopsis cold inducible promoter cor15a were produced to test the efficiency of this gene in barley. After a preliminary test, the best performing lines were subjected to freezing at -11°C and -12°C. Frost tolerance was assessed measured the F(v)/F(m) parameter widely used to indicate the maximum quantum yield of photosystem II photochemistry in the dark adapted state. Three transgenic lines showed significantly increased tolerance. These selected lines were further studied under a complex stress applying cold and hypoxia at germinating stage. In these conditions the three selected transgenic lines outperformed the wild type barley in terms of germination vigour. The transgenic plants also showed a significant modification of their metabolism under cold/hypoxia conditions as demonstrated through the assessment of the activity of key enzymes involved in anoxic stress response. None of the transgenic lines showed dwarfism, just a slight retarded growth. These results provide evidence that the cold dependent expression of Osmyb4 can efficiently improved frost tolerance and germination vigour at low temperature without deleterious effect on plant growth.

H protein of bacteriophage 16-3 and RkpM protein of Sinorhizobium meliloti 41 are involved in phage adsorption.

The strain-specific capsular polysaccharide KR5 antigen of Sinorhizobium meliloti 41 is required both for invasion of the symbiotic nodule and for the adsorption of bacteriophage 16-3. In order to know more about the genes involved in these events, bacterial mutants carrying an altered phage receptor were identified by using host range phage mutants. A representative mutation was localized in the rkpM gene by complementation and DNA sequence analysis. A host range phage mutant isolated on these phage-resistant bacteria was used to identify the h gene, which is likely to encode the tail fiber protein of phage 16-3. The nucleotide sequences of the h gene as well as a host range mutant allele were also established. In both the bacterial and phage mutant alleles, a missense mutation was found, indicating a direct contact between the RkpM and H proteins in the course of phage adsorption. Some mutations could not be localized in these genes, suggesting that additional components are also important for bacteriophage receptor recognition.