In vitro synergistic antibacterial activity of Salvia officinalis L. and some preservatives

The aim of this work was to investigate the antibacterial activity of aqueous extracts of the species Salvia officinalis L. and its synergistic action with the preservatives sodium nitrite, sodium benzoate and potassium sorbate in vitro against selected food spoiling bacteria. Synergism was assessed by the checkerboard assay method and quantitatively represented by the FIC index. Synergistic action was established for aqueous extract/sodium benzoate, aqueous extract/potassium sorbate, aqueous extract/sodium nitrite combinations. Synergism was detected in relation to: Agrobacterium tumefaciens, Bacillus subtilis and Proteus sp. Synergism was established at plant extract and preservative concentrations corresponding up to 1/8 MIC values

PHENOTYPIC VARIABILITY OF FERTILITY AND MILK TRAITS IN OFFSPRING OBTAINED BY INSEMINATION BY SEXED AND CONVENTIONAL SEMEN OF HOLSTEIN BREED BULLS

The objective of this paper was to compare heifers reproductive traits and characteristics of their calves after artificial insemination performed by conventional (non-sexed) and sexed sperm on 6 commercial farms in Serbia. Conception rate was 55% and 44% for conventional and sexed semen, an average gestation length being 274.6 and 274.9 days, respectively. Average body mass at birth was 37.47 and 36.75 kg for non-sexed and sexed semen, respectively. The rate of stillbirths and twinning was 6.19 and 3.78% for conventional and 7.54 and 1.13% for sexed semen, respectively. The use of conventional semen exerted no statistically significant (P>0.05) effect on female: male calves relationship (51.96 : 48.04) while artificial insemination by sexed semen highly significantly (P<0.01) changed calf sex-ratio (85.10 : 14.90). First-calf heifers originating from sires whose sperm was obtained in conventional way produced 7880 kg milk with 269 kg milk fat and 242 kg protein in standard lactation, while first-calf heifers originating from sires whose sperm was sex-sorted produced 8184 kg milk with 251 kg milk fat and 242.3 kg protein. Type of insemination (conventional and sexed semen) did not significantly affect the studied milk yield traits (P>0.05)

UPORABA UMJETNIH NEURONSKIH MREŽA U PREDVIĐANJU PROFESIONALNIH KRETANJA MATURANATA

Aim of this paper is to examine the possibility of predicting professional choice of secondary school graduates by using artificial neural network for the needs of enrolment policy planning at the Faculty of Mechanical Engineering in Belgrade. The problem of professional choices prediction for graduates has been carried out on the sample of 119 graduates from two Belgrade vocational schools. Factors influencing professional choice of secondary school students grouped in twelve input variables proved to be as suitable for predicting professional movements of graduates. Results of this research represent the base for the further researches aiming to improve the Faculty enrolment policy.Svrha ovog rada je istražiti mogućnosti predviđanja izbora profesije maturanata uporabom umjetnih neuronskih mreža zbog potrebe planiranja upisne politike Strojarskog fakulteta u Beogradu. Istraživanje predviđanja odabira profesije provedeno je na uzorku od 119 maturanata dvije beogradske strukovne srednje škole. Svrstavanje čimbenika koji utječu na izbor profesije kod srednjoškolaca u dvanaest ulaznih varijabli pokazalo se odgovarajućim za predviđanje profesionalnih kretanja maturanata. Rezultati ovog istraživanja predstavljaju osnovu za daljnja istraživanja usmjerena poboljšanju upisne politike Fakulteta

Modelling cholesterol effects on the dynamics of the hypothalamic-pituitary-adrenal (HPA) axis

A mathematical model of the hypothalamic-pituitary-adrenal (HPA) axis with cholesterol as a dynamical variable was derived to investigate the effects of cholesterol, the primary precursor of all steroid hormones, on the ultradian and circadian HPA axis activity. To develop the model, the parameter space was systematically examined by stoichiometric network analysis to identify conditions for ultradian oscillations, determine conditions under which dynamic transitions, i.e. bifurcations occur and identify bifurcation types. The bifurcations were further characterized using numerical simulations. Model predictions agree well with empirical findings reported in the literature, indicating that cholesterol levels may critically affect the global dynamics of the HPA axis. The proposed model provides a base for better understanding of experimental observations, it may be used as a tool for designing experiments and offers useful insights into the characteristics of basic dynamic regulatory mechanisms that, when impaired, may lead to the development of some modern-lifestyle-associated diseases

Phosphorus Deficiency Induced Silicon Mobilization in Grapevine Rhizosphere: A Field Study

Silicon (Si) uptake by crops is well studied and Si transporters have been characterized in various crop species, including grapevine. However, information on the rhizosphere mobilization of Si is still lacking and virtually no information is available on grapevine. Our previous study showed that grapevine is a phosphorus (P)-efficient species with a high root capacity to mobilize P from the rhizosphere by the released of organic anions (mainly citrate). The field experiment was established in 12-y-old vineyard with the cultivar ‘Chardonnay’, grafted on 5BB rootstock under extremely low P conditions (Olsen P < 3 mg kg-1). Four own-designed rhizotrons (80 cm depth) were installed in a vineyard enabling easy access to the new intact roots. The following treatments were performed: –P/–Si, +P/–Si, –P/+Si (soil application) and –P/+Si (foliar application). The samples of rhizosphere and bulk soils, root exudates from intact root tips and vine tissues (root and leaves) were collected at different growth stages according to Eichhorn-Lorentz (E-L) system: flowering (E-L stage 23), berries pea-size (E-L stage 31), and veraison (E-L stage 35). In addition to Si and P concentrations in the tissues, the expressions of VvALMT, VvMATE (encoding efflux transporters for malate and citrate, respectively), and VvNIP2.1 (encoding Si influx transporter) were also determined. Phosphate fertilization decreased, while low soil P and Si fertilization increased Si availability in the rhizosphere. At the flowering stage, –P plants accumulated more Si than the P-fertilized ones and was comparable to the Si-fertilized plants. Foliar application of Si was less effective in comparison with soil application unless at the veraison stage. The leaf Si concentrations showed a clear seasonal pattern being the highest at the veraison stage. Exudation rate of citrate also showed a clear seasonal pattern and was significantly higher in the –P/–Si than in +P/–Si plants, which was followed by an increased Si availability in the vine rhizosphere. Overall, low P conditions induced Si accumulation in the leaves due to increased exudation of organic anions that can also mobilize Si in the rhizosphere, thereby increasing Si uptake by grapevine

Silicon Differently Affects Apoplastic Binding of Excess Boron in Wheat and Sunflower Leaves

Monocots and dicots differ in their boron (B) requirement, but also in their capacity to accumulate silicon (Si). Although an ameliorative effect of Si on B toxicity has been reported in various crops, differences among monocots and dicots are not clear, in particular in light of their ability to retain B in the leaf apoplast. In hydroponic experiments under controlled conditions, we studied the role of Si in the compartmentation of B within the leaves of wheat (Triticum vulgare L.) as a model of a high-Si monocot and sunflower (Helianthus annuus L.) as a model of a low-Si dicot, with the focus on the leaf apoplast. The stable isotopes 10B and 11B were used to investigate the dynamics of cell wall B binding capacity. In both crops, the application of Si did not affect B concentration in the root, but significantly decreased the B concentration in the leaves. However, the application of Si differently influenced the binding capacity of the leaf apoplast for excess B in wheat and sunflower. In wheat, whose capacity to retain B in the leaf cell walls is lower than in sunflower, the continuous supply of Si is crucial for an enhancement of high B tolerance in the shoot. On the other hand, the supply of Si did not contribute significantly in the extension of the B binding sites in sunflower leaves. © 2023 by the authors

Duration of priming with silicon modulates antioxidative response of wheat to salinity stress

Priming with silicon (Si) may increase plant resistance to biotic and abiotic stresses, in particular in conjunction with its subsequent application. Yet, the very effect of the duration of priming with Si is less understood. Here, we investigated the effect of the duration of priming with Si on components of the antioxidative response of wheat exposed to a gradient of salinity stress. After priming with 1.5 mM Si(OH)4 (0, 1, and 3 days), wheat seedlings were exposed to different NaCl levels (0, 30, and 60 mM) without (-Si) or with (+Si) supply of 1.5 mM Si(OH)4. The activities of superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX), and the concentration of malondialdehyde (MDA) were measured in shoots and roots after 1 and 5 days of NaCl treatments. Interaction of priming duration and addition of Si on antioxidative variables were analyzed using general regression model. Overall, priming had no influence on -Si plants under salt stress. On the day 1 of NaCl exposure, priming duration did not affect SOD and APX activities neither in roots nor in shoots. However, on the day 5 of NaCl exposure longer priming with Si significantly increased the activities of APX and SOD in both roots and shoots. The activity of CAT showed no response to priming with Si and subsequent Si supply in both plant organs irrespectively of the duration of NaCl exposure. Interestingly, in both organs the concentrations of MDA as a proxy for oxidative damage of plant membranes were very clearly and consistently lower after 3 days of priming with Si (compared to 1 day or no priming) during the whole period of NaCl exposure. This study demonstrated that longer priming with Si can enhance the ameliorative effect of Si supply on the antioxidative response of wheat plants to a gradient of salinity stress

Dynamic transitions in a model of the hypothalamic-pituitary-adrenal axis

Dynamic properties of a nonlinear five-dimensional stoichiometric model of the hypothalamicpituitary-adrenal (HPA) axis were systematically investigated. Conditions under which qualitative transitions between dynamic states occur are determined by independently varying the rate constants of all reactions that constitute the model. Bifurcation types were further characterized using continuation algorithms and scale factor methods. Regions of bistability and transitions through supercritical Andronov-Hopf and saddle loop bifurcations were identified. Dynamic state analysis predicts that the HPA axis operates under basal (healthy) physiological conditions close to an Andronov-Hopf bifurcation. Dynamic properties of the stress-control axis have not been characterized experimentally, but modelling suggests that the proximity to a supercritical Andronov-Hopf bifurcation can give the HPA axis both, flexibility to respond to external stimuli and adjust to new conditions and stability, i.e., the capacity to return to the original dynamic state afterwards, which is essential for maintaining homeostasis. The analysis presented here reflects the properties of a low-dimensional model that succinctly describes neurochemical transformations underlying the HPA axis. However, the model accounts correctly for a number of experimentally observed properties of the stress-response axis. We therefore regard that the presented analysis is meaningful, showing how in silico investigations can be used to guide the experimentalists in understanding how the HPA axis activity changes under chronic disease and/or specific pharmacological manipulations

HYPERLIPIDEMIA IN ACUTE PANCREATITIS: CONCOMITANT DISORDER OR A CAUSE?

Acute pancreatitis is a common condition with alcohol and gallstones being the most frequent etiologies. The aim of our study was to determine the prevalence of hyperlipidemia, its etiopathogenetic role and influence on outcomes in patients with acute pancreatitis.The study included 47 patients admitted to our clinic for acute pancreatitis during one year period. On admission patients with hyperlipidemia were compared to those without it, regarding following parameters: body mass index, Glasgow score, organ failure occurrence, local complications occurrence (pancreatic necrosis, pseudocyst, abscess, jaundice, gastric outlet syndrome), intensive care unit stay and death. The results of the study revealed high incidence of hyperlipidemia in 51% of examined acute pancreatitis patients with the prevalence of severe forms in more than half of these patients. Dominant lipid disorder was hypertriglyceridemia, followed by hypercholesterolemia. It was clearly demonstrated that patients with hyperlipidemia, especially hypertriglyceridemia, had more severe acute pancreatitis, higher incidence of complications and poorer outcome compared to normolipemic patients. Hyperlipidemia in patients with acute pancreatitis should be considered and treated by a clinician as a separate serious problem, both when being a cause and a concomitant disorder. Hypolipidemic therapy should be administered both in urgent acute pancreatitis settings and as a long-term treatment aimed to prevent inflammation recurrence by successful persistent serum lipid levels control.Key words: Hyperlipidemia, acute pancreatitis