Effect of Phytotoxin from Nematode-induced Pinewilt on Bursaphelenchus xylophilus and Ceratocystis ips

A phytotoxic extract from Pinus sylvestris infected with Bursaphelenchus xylophilus inhibited growth of the blue-strain fungus Ceratocystis ips and caused temporary paralysis in vitro of B. xylophilus. Although the nematodes recovered from paralysis, final population size of B. xylophilus was suppressed by the toxin. Extracts from noninfected P. sylvestris affected neither the fungus nor the nematode.     

Structural analysis of human neutrophil migration: Centriole, microtubule, and microfilament orientation and function during chemotaxis

Orientation of nucleus, centriole, microtubules, and microfilaments within human neutrophils in a gradient of chemoattractant (5 percent Escherichia coli endotoxin-activated serum) was evaluated by electron microscopy. Purified neutropils (hypaque-Ficoll) were placed in the upper compartment of chemotactic chambers. Use of small pore (0.45 μm) micropore filters permitted pseudopod penetration, but impeded migration. Under conditions of chemotaxis with activated serum beneath the filter, the neutrophil population oriented at the filter surface with nuclei located away from the stimulus, centrioles and associated radial array of microtubules beneath the nuclei, and microfilament-rich pseudopods penetrating the filter pores. Reversal of the direction of the gradient of the stimulus (activated serum above cells) resulted in a reorientation of internal structure which preceded pseudopod formation toward the activated serum and migration off the filter. Coordinated orientation of the entire neutrophil population did not occur in buffer (random migration) or in a uniform concentration of activated serum (activated random migration). Conditions of activated random migration resulted in increased numbers of cells with locomotory morphology, i.e. cellular asymmetry with linear alignment of nucleus, centriole, microtubule array, and pseudopods. Thus, activated serum increased the number of neutrophils exhibiting locomotory morphology, and a gradient of activated serum induced the alignment of neutrophils such that this locomotory morphology was uniform in the observed neutrophil populayion. In related studies, cytochalasin B and colchicines were used to explore the role of microfilaments and microtubules in the neutrophil orientation and migration response to activated serum. Cytochalasin B (3.0 μg/ml) prevented migration and decreased the microfilaments seen, but allowed normal orientation of neutrophil structures. In an activated serum gradient, colchicines, but not lumicolchicine, decreased the orientation of nuclei and centrioles, and caused a decrease in centriole-associated microtubules in concentrations as low as 10(-8) to 10(-7) M. These colchicines effects were associated with the rounding of cells and impairment of pseudopod formation. The impaired pseudopod formation was characterized by an inability to form pseudopods in the absence of a solid substrate, a formation of narrow pseudopods within a substrate, and a defect in pseudopod orientation in an activated serum gradient. Functional studies of migration showed that colchicines, but not lumicolchicine, minimally decreased activated random migration and markedly inhibited directed migration, but had not effect on random migration. These studies show that, although functioning microfilaments are probably necessary for neutrophil migration, intact microtubules are essential for normal pseudopod formation and orientation, and maximal unidirectional migration during chemotaxis.     

Erratum to: Reserpine Is the New Addition into the Repertoire of AcrB Efflux Pump Inhibitors [Molecular Biology, 2019, Vol. 53, No. 4, pp. 596–605]

Molecular Biology - erratum     

Mathematical modelling of ciliary propulsion of an electrically-conducting Johnson-Segalman physiological fluid in a channel with slip

Bionic systems frequently feature electromagnetic pumping and offer significant advantages over conventional designs via intelligent bio-inspired properties. Complex wall features observed in nature also provide efficient mechanisms which can be utilized in biomimetic designs. The characteristics of biological fluids are frequently non-Newtonian in nature. In many natural systems super-hydrophobic slip is witnessed. Motivated by these phenomena, in this paper, we discussed a mathematical model for the cilia-generated propulsion of an electrically-conducting viscoelastic physiological fluid in a ciliated channel under the action of magnetic field. The rheological behavior of the fluid is simulated with the Johnson-Segalman constitutive model which allows internal wall slip. The regular or coordinated movement of the ciliated edges (which line the internal walls of the channel) is represented by a metachronal wave motion in the horizontal direction which generates a two-dimensional velocity profile. This mechanism is imposed by a periodic boundary condition which generates propulsion in the channel flow. Under the classical lubrication approximation, the boundary value problem is non-dimensionalized and solved analytically with a perturbation technique. The influence of the geometric, rheological (slip and Weissenberg number) and magnetic parameters on velocity, pressure gradient and the pressure rise (evaluated via the stream function in symbolic software) are presented graphically and interpreted at length.     

Diazoxide preconditioning of endothelial progenitor cells from streptozotocin-induced type 1 diabetic rats improves their ability to repair diabetic cardiomyopathy

Molecular and Cellular Biochemistry - Type 1 diabetes mellitus (DM) is a strong risk factor for the development of diabetic cardiomyopathy (DCM) which is the leading cause of morbidity and...     

Non-equilibrium structural dynamics of supercoiled DNA plasmids exhibits asymmetrical relaxation

Many cellular processes occur out of equilibrium. This includes site-specific unwinding in supercoiled DNA, which may play an important role in gene regulation. Here, we use the Convex Lens-induced Confinement (CLiC) single-molecule microscopy platform to study these processes with high-throughput and without artificial constraints on molecular structures or interactions. We use two model DNA plasmid systems, pFLIP-FUSE and pUC19, to study the dynamics of supercoiling-induced secondary structural transitions after perturbations away from equilibrium. We find that structural transitions can be slow, leading to long-lived structural states whose kinetics depend on the duration and direction of perturbation. Our findings highlight the importance of out-of-equilibrium studies when characterizing the complex structural dynamics of DNA and understanding the mechanisms of gene regulation.     

Hypotensive action of coumarin glycosides from Daucus carota.

Daucus carota (carrot) has been used in traditional medicine to treat hypertension. Activity-directed fractionation of aerial parts of D. carota resulted in the isolation of two cumarin glycosides coded as DC-2 and DC-3. Intravenous administration of these compounds caused a dose-dependent (1-10 mg/kg) fall in arterial blood pressure in normotensive anaesthetised rats. In the in vitro studies, both compounds caused a dose-dependent (10-200 microg/ml) inhibitory effect on spontaneously beating guinea pig atria as well as on the K+ -induced contractions of rabbit aorta at similar concentrations. These results indicate that DC-2 and DC-3 may be acting through blockade of calcium channels and this effect may be responsible for the blood pressure lowering effect of the compounds observed in the in vivo studies.     

Antimicrobial screening of polyherbal formulations traditionally used against gastrointestinal diseases

Emerging antibiotic resistance has become a cosmopolitan problem and evoking researchers to search for new antimicrobials from natural constituents. The present study was intended to test the antimicrobial potential of traditionally used unexplored polyherbal recipes for curing digestive ailments. A total of 25 plants species were combined in different ratios to form 14 polyherbal recipes. After collecting and grinding plant parts, methanolic extracts of 14 polyherbal recipes were prepared by the cold maceration process. Antibacterial and antifungal activity of the polyherbal extracts was checked by agar well diffusion method at a concentration of 50 mg/ ml while minimum inhibitory concentration (MIC) was determined by serial dilution method. Polyherbal recipes B and D showed significant inhibition zone each against Vibrio cholerae (25.63; p < 0.001). Recipe G (23.33; p < 0.001) showed better efficacy against Escherichia coli. Recipe E and G significantly inhibited Proteus species (28.33; 24.33; p < 0.001). Recipe B was highly effective against Salmonella typhi. Recipe C, A and F had significant antifungal affect and inhibited Aspergillus nigar (28.67; p < 0.05), Aspergillus fumigatus (27; p < 0.01) Trichoderma (30; p < 0.001), Rhizopus (19.67; p < 0.01), and Fusarium graminearum (28.67;p < 0.001). Polyherbal formulations A, B, D, K, and N were active with the lowest concentration. MIC ranges within 3.12–25 mg/ml while minimum bactericidal concentration (MBC) between 12.5 and 50 mg/ml. Polyherbal recipes’ A, B, D, G, K and N have enhanced antimicrobial potential with better efficacy than tested antibiotics and should be evaluated for further scientific validation.