Stimulation frequency-dependent nonadrenergic noncholinergic airway responses of the guinea pig

We examined the inhibitory and excitatory components of the nonadrenergic noncholinergic (NANC) innervation of the guinea pig airways by in vivo and in vitro methods. Electrical stimulation of the vagus in chloralose-urethan-anesthetized guinea pigs after cholinergic and adrenergic blockade produced peripheral airway constriction (insufflation pressure) and tracheal relaxation (pouch pressure). Vagal stimulation was applied for 90 s at 5-V pulses of 2-ms duration at frequencies of 5, 15, 25, and 35 Hz in each group (n = 6). The pouch relaxation peaked at 15 Hz. The insufflation pressure was highest at 5 Hz. Field stimulations of the same frequencies were applied on tracheal spirals and lung parenchymal strips. The maximal relaxation of the trachea occurred at 15-35 Hz. The lung parenchymal strip tensions increased almost linearly as the frequency increased from 5 to 35 Hz. The results of the study indicated a frequency-dependent response for both excitatory and inhibitory components of the NANC, which operate at different frequencies for optimal responses.     

Naringenin Ameliorates Chronic Sleep Deprivation‐Induced Pain via Sirtuin1 Inhibition

Neurochemical Research - Growing experimental evidences have suggested the reciprocal correlation between sleep deprivation and pain. Inflammation and oxidative stress are among the key pathways...     

Role of luminous bacteria in chitin degradation in the intestine of fish

Summary Chitinolytic activity of three luminous bacterial species viz.,Vibrio harveyi, V. fischeri andPhotobacterium leiognathi, was estimated. The stomach of the fishTachysurus arius which harbours luminous bacteria also possesses chitinase activity. The magnitude of non-bacterial chitinase activity appeared to exceed that of the bacterial origin as evidenced by the enzyme activity detected in fish tested with antibiotics. In fishes which lack an indigenous chitinase, the microbial chitinase is likely to play an important role in chitin digestion.

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Role des bactéries lumineuses dans la dégradation de la chitine dans l'intestin de poisson

Résumé On a estimé l'activité chitinolytique de trois espèces de bactéries lumineuses, notammentVibrio harveyi, V. fischeri andPhoto bacterium leiognathi. L'estomac du poisson Tachysurus arius qui héberge les bactéries lumineuses possède aussi l'activité chitinasique. L'activité chitinasique non-bactérienne dépasse celle d'origine bactérienne ainsi qu'il en résulte de l'activité enzymatique chez les poissons traités aux antibiotiques. Chez les poissons déficients en activité chitinasique indigène, la chitinase microbienne joue probablement un rôle important dans la digestion de la chitine.

     

Use of coastal waters as condenser coolant in electric power plants: Impact on phytoplankton and primary productivity

(1) Studies on phytoplankton entrained in cooling system of a power plant revealed a reduction in biomass and gross primary productivity (GPP) at outfall, compared to intake.     

Relative tolerance of cirripede larval stages to acute thermal shock: A laboratory study

(1) Meroplankters drawn into once-through cooling circuits of coastal power plants are subjected to transient thermal stress. The effect of such acute thermal shock on the development of barnacle larvae was studied in the laboratory.

(2) The response of the barnacle larvae (naupliar and cyprid stages) to elevated temperature was dependent on exposure time and their stage of development.

(3) Among the stages tested, N-6 larvae showed maximum tolerance. Exposure to 37°C did not affect larval survival, but delayed development of N-2 larva to cypris by one day.

(4) Exposure at 40°C delayed, hastened or did not affect the development time of N-2 and N-4 larvae through cypris, depending on exposure time.

(5) Ten mins exposure at 43°C proved lethal to all larval stages with mortality ranging from 20 to 86%.

(6) Development success of the surviving larvae, measured in terms of cypris yield, showed no significant difference from controls, at temperatures below 40°C.

(7) Settlement activity was significantly affected in only those cyprid larvae which were exposed to 43°C for 10 min.

(8) Results of the present study indicate that thermal stress experienced in the once-through cooling system does not have significant impact on survival and development of the barnacle larvae at temperatures of 37–40°C.     

Entrapping unusual folding characteristics of the beta-Ala residues in a model peptide: Boc-beta-Ala-Aib-beta-Ala-NHCH3.

Crystal structure analysis of a model peptide: Boc-beta-Ala-Aib-beta-Ala-NHCH3 (beta-Ala: 3-amino propionic acid; Aib: alpha-aminoisobutyric acid) revealed distinct conformational preferences for folded [phi approximately 136 degrees, mu approximately -62 degrees, psi approximately 100 degrees] and semifolded [phi approximately 83 degrees, mu approximately -177 degrees, psi approximately -117 degrees] structures of the N-and C-terminus beta-Ala residues, respectively. The overall folded conformation is stabilized by unusual Ni...H-Ni+1 and nonconventional C-H...O intramolecular hydrogen bonding interactions.     

Multicellular Architecture of Malignant Breast Epithelia Influences Mechanics

Cell–matrix and cell–cell mechanosensing are important in many cellular processes, particularly for epithelial cells. A crucial question, which remains unexplored, is how the mechanical microenvironment is altered as a result of changes to multicellular tissue structure during cancer progression. In this study, we investigated the influence of the multicellular tissue architecture on mechanical properties of the epithelial component of the mammary acinus. Using creep compression tests on multicellular breast epithelial structures, we found that pre-malignant acini with no lumen (MCF10AT) were significantly stiffer than normal hollow acini (MCF10A) by 60%. This difference depended on structural changes in the pre-malignant acini, as neither single cells nor normal multicellular acini tested before lumen formation exhibited these differences. To understand these differences, we simulated the deformation of the acini with different multicellular architectures and calculated their mechanical properties; our results suggest that lumen filling alone can explain the experimentally observed stiffness increase. We also simulated a single contracting cell in different multicellular architectures and found that lumen filling led to a 20% increase in the “perceived stiffness” of a single contracting cell independent of any changes to matrix mechanics. Our results suggest that lumen filling in carcinogenesis alters the mechanical microenvironment in multicellular epithelial structures, a phenotype that may cause downstream disruptions to mechanosensing.     

9-cis-canthaxanthin exhibits higher pro-apoptotic activity than all-trans-canthaxanthin isomer in THP-1 macrophage cells

All-trans-canthaxanthin (4, 4′-diketo β-carotene) but not 9-cis-canthaxanthin has been shown to induce apoptosis in some cell lines. In this study apoptotic activity of 9-cis-canthaxanthin on THP-1 macrophage is reported. Comparison of apoptotic activities of the two canthaxanthin isomers on this cell line by annexin V-cy3 and TUNEL assays indicated the higher pro-apoptotic activity of 9-cis-isomer than the all-trans-isomer. Canthaxanthin-induced apoptosis in this cell line was found to be accompanied by increased caspase-3 and caspase-8 activities, indicating its progression via caspase cascade. Induction of both caspase activities was higher by 9-cis-canthaxanthin than that by trans-canthaxanthin. All these results suggest that canthaxanthin stereoisomers differentially induce apoptosis of THP-1 monocyte/macrophage.     

Hydrodynamic Determinants of Cell Necrosis and Molecular Delivery Produced by Pulsed Laser Microbeam Irradiation of Adherent Cells

Time-resolved imaging, fluorescence microscopy, and hydrodynamic modeling were used to examine cell lysis and molecular delivery produced by picosecond and nanosecond pulsed laser microbeam irradiation in adherent cell cultures. Pulsed laser microbeam radiation at λ = 532 nm was delivered to confluent monolayers of PtK₂ cells via a 40×, 0.8 NA microscope objective. Using laser microbeam pulse durations of 180–1100 ps and pulse energies of 0.5–10.5 μJ, we examined the resulting plasma formation and cavitation bubble dynamics that lead to laser-induced cell lysis, necrosis, and molecular delivery. The cavitation bubble dynamics are imaged at times of 0.5 ns to 50 μ  s after the pulsed laser microbeam irradiation, and fluorescence assays assess the resulting cell viability and molecular delivery of 3 kDa dextran molecules. Reductions in both the threshold laser microbeam pulse energy for plasma formation and the cavitation bubble energy are observed with decreasing pulse duration. These energy reductions provide for increased precision of laser-based cellular manipulation including cell lysis, cell necrosis, and molecular delivery. Hydrodynamic analysis reveals critical values for the shear-stress impulse generated by the cavitation bubble dynamics governs the location and spatial extent of cell necrosis and molecular delivery independent of pulse duration and pulse energy. Specifically, cellular exposure to a shear-stress impulse J?0.1$J\mathrm{?}0.1$ Pa s ensures cell lysis or necrosis, whereas exposures in the range of 0.035?J?0.1$0.035\mathrm{?}J\mathrm{?}0.1$ Pa s preserve cell viability while also enabling molecular delivery of 3 kDa dextran. Exposure to shear-stress impulses of J?0.035$J\mathrm{?}0.035$ Pa s leaves the cells unaffected. Hydrodynamic analysis of these data, combined with data from studies of 6 ns microbeam irradiation, demonstrates the primacy of shear-stress impulse in determining cellular outcome resulting from pulsed laser microbeam irradiation spanning a nearly two-orders-of-magnitude range of pulse energy and pulse duration. These results provide a mechanistic foundation and design strategy applicable to a broad range of laser-based cellular manipulation procedures.