Ablation of smooth muscle myosin heavy chain SM2 increases smooth muscle contractility and results in postnatal death in mice

The smooth muscle myosin heavy chains (SMHC) are motor proteins powering smooth muscle contraction. Alternate splicing of SHMC gene at the C-terminus produces SM1, and SM2 myosin isoforms; SM2 (200 kDa) contains a unique 9-amino-acid sequence at the carboxyl terminus, whereas SM1 (204 kDa) has a 43 amino acid non-helical tail region. To date the functional difference between C-terminal isoforms has not been established; therefore, we used an exon-specific gene targeting strategy and generated a mouse model specifically deficient in SM2. Deletion of exon-41 of the SMHC gene resulted in a complete loss of SM2 in homozygous (_SM2^-/-^_) mice, accompanied by a concomitant down-regulation of SM1 in bladders. While heterozygous (_SM2^+/-^_) mice appeared normal and fertile, _SM2^-/-^_ mice died within 30 days after birth. The peri-mortal _SM2^-/-^_ mice showed reduced body weight, distention of the bladder and alimentary tract, and end-stage hydronephrosis. Interestingly, strips from _SM2^-/-^_ bladders showed increased contraction to K^+^ depolarization or M3 receptor activation. These results suggest that SM2 myosin has a distinct functional role in smooth muscle, and the deficiency of SM2 increases smooth muscle contractility, and causes dysfunctions of smooth muscle organs, including the bladder that leads to the end-stage hydronephrosis and postnatal death

Construction of two whole genome radiation hybrid panels for dromedary (Camelus dromedarius): 5000RAD and 15000RAD

The availability of genomic resources including linkage information for camelids has been very limited. Here, we describe the construction of a set of two radiation hybrid (RH) panels (5000RAD and 15000RAD) for the dromedary (Camelus dromedarius) as a permanent genetic resource for camel genome researchers worldwide. For the 5000RAD panel, a total of 245 female camel-hamster radiation hybrid clones were collected, of which 186 were screened with 44 custom designed marker loci distributed throughout camel genome. The overall mean retention frequency (RF) of the final set of 93 hybrids was 47.7%. For the 15000RAD panel, 238 male dromedary-hamster radiation hybrid clones were collected, of which 93 were tested using 44 PCR markers. The final set of 90 clones had a mean RF of 39.9%. This 15000RAD panel is an important high-resolution complement to the main 5000RAD panel and an indispensable tool for resolving complex genomic regions. This valuable genetic resource of dromedary RH panels is expected to be instrumental for constructing a high resolution camel genome map. Construction of the set of RH panels is essential step toward chromosome level reference quality genome assembly that is critical for advancing camelid genomics and the development of custom genomic tools

Bimodality and hysteresis in systems driven by confined L\'evy flights

We demonstrate occurrence of bimodality and dynamical hysteresis in a system describing an overdamped quartic oscillator perturbed by additive white and asymmetric L\'evy noise. Investigated estimators of the stationary probability density profiles display not only a turnover from unimodal to bimodal character but also a change in a relative stability of stationary states that depends on the asymmetry parameter of the underlying noise term. When varying the asymmetry parameter cyclically, the system exhibits a hysteresis in the occupation of a chosen stationary state.Comment: 4 pages, 5 figures, 30 reference

Accounting for both electron--lattice and electron--electron coupling in conjugated polymers: minimum total energy calculations on the Hubbard--Peierls hamiltonian

Minimum total energy calculations, which account for both electron--lattice and electron--electron interactions in conjugated polymers are performed for chains with up to eight carbon atoms. These calculations are motivated in part by recent experimental results on the spectroscopy of polyenes and conjugated polymers and shed light on the longstanding question of the relative importance of electron--lattice vs. electron--electron interactions in determining the properties of these systems.Comment: 6 pages, Plain TeX, FRL-PSD-93GR

Testing of Semi–Strong Form of Efficiency: an Empirical Study on Stock Market Reaction Around Dividend Announcement

Purpose: The purpose of this study is to examine the efficiency of the Indian stock market of the Nifty IT index over the dividend announcement for five years from 2016 to 2020.   Theoretical framework: A reward procured by the shareholders on their equities is, of course, the dividend. A leading area of concern is the dividend announcement. According to the theory of efficient markets, stock prices accurately reflect all available information. This demonstrates that the prices are correct and fair. The market should therefore respond immediately to an event in this instance the dividend announcement. Therefore, depending on publicly available information will not provide investors with the possibility to consistently generate extraordinary returns.   Design/ methodology/ approach: The study attempts to validate the event study approach while investigating the semi-strong form of efficiency. Daily share prices of five companies out of ten of the Nifty IT index were observed to test the Efficient Market Hypothesis. 31 days event window has been employed to calculate the abnormal returns of the selected sample around dividend issue announcements also t-test was applied to assess the level of significance.   Findings: The study found that the stock market was efficient in its semi strong form and the investors could not make excess returns over the dividend announcement of the Nifty IT index.   Research, Practical & social implications: This study eliminates the possibility for investors to beat the average market returns. It is significant since it affects stock market investment choices.   Originality/ Values: The majority of studies are only able to analyse the overall average abnormal return and cumulative average abnormal return of chosen companies; it is difficult to locate studies that focus on the abnormal return for each individual company. The t test for each company-wise abnormal returns, overall average abnormal returns, and cumulative average abnormal returns were acquired and tested at the 5% level of significance in order to determine the significance.

Development of an in vitro periodontal biofilm model for assessing antimicrobial and host modulatory effects of bioactive molecules

Background: Inflammation within the oral cavity occurs due to dysregulation between microbial biofilms and the host response. Understanding how different oral hygiene products influence inflammatory properties is important for the development of new products. Therefore, creation of a robust host-pathogen biofilm platform capable of evaluating novel oral healthcare compounds is an attractive option. We therefore devised a multi-species biofilm co-culture model to evaluate the naturally derived polyphenol resveratrol (RSV) and gold standard chlorhexidine (CHX) with respect to anti-biofilm and anti-inflammatory properties.<p></p> Methods: An in vitro multi-species biofilm containing <i>S. mitis, F. nucleatum, P. Gingivalis</i> and <i>A. Actinomycetemcomitans</i> was created to represent a disease-associated biofilm and the oral epithelial cell in OKF6-TERT2. Cytotoxicity studies were performed using RSV and CHX. Multi-species biofilms were either treated with either molecule, or alternatively epithelial cells were treated with these prior to biofilm co-culture. Biofilm composition was evaluated and inflammatory responses quantified at a transcriptional and protein level.<p></p> Results: CHX was toxic to epithelial cells and multi-species biofilms at concentrations ranging from 0.01-0.2%. RSV did not effect multi-species biofilm composition, but was toxic to epithelial cells at concentrations greater than 0.01%. In co-culture, CHX-treated biofilms resulted in down regulation of the inflammatory chemokine IL-8 at both mRNA and protein level. RSV-treated epithelial cells in co-culture were down-regulated in the release of IL-8 protein, but not mRNA.<p></p> Conclusions: CHX possesses potent bactericidal properties, which may impact downstream inflammatory mediators. RSV does not appear to have bactericidal properties against multi-species biofilms, however it did appear to supress epithelial cells from releasing inflammatory mediators. This study demonstrates the potential to understand the mechanisms by which different oral hygiene products may influence gingival inflammation, thereby validating the use of a biofilm co-culture model.<p></p&gt

A comparative study of spinal bupivacaine with fentanyl versus ultrasound-guided combined lumbar plexus and sciatic nerve block in lower limb orthopedic procedures: A prospective randomized controlled trial.

BackgroundSpinal anesthesia with bupivacaine and fentanyl is widely used for its rapid onset, while ultrasound-guided lumbar plexus and sciatic nerve blocks are gaining popularity for prolonged postoperative analgesia with fewer systemic side effects. Aim: To compare the efficacy of spinal bupivacaine with fentanyl versus ultrasound-guided combined lumbar plexus and sciatic nerve blocks in lower limb orthopedic procedures. Methods This prospective randomized controlled trial was conducted on 50 patients aged 18–65 years undergoing elective lower limb orthopedic surgeries. Patients were randomized into two groups: Group A received spinal bupivacaine (12.5 mg) + fentanyl (25 mcg); Group B received ultrasound-guided lumbar plexus block with 30 ml of 0.25% bupivacaine and sciatic nerve block with 25 ml of 0.25% bupivacaine. Primary outcomes included onset and duration of sensory and motor blocks, and duration of analgesia. Secondary outcomes included hemodynamic changes and complications. Results Both groups were comparable in baseline demographics, with a mean age of 49 years and a similar distribution of sex and ASA physical status. The onset of sensory and motor block was significantly faster in Group A (5–8 min and 6–10 min) compared to Group B (10–20 min and 12–20 min; p<0.001). However, Group B had a significantly longer duration of sensory block (6–8 hrs), motor block (3–4 hrs), and analgesia (8–12 hrs) (p<0.001). Hypotension was more common in Group A (48%) than in Group B (32%). Two patients in Group B required conversion to general anesthesia due to technical difficulties. Conclusion Ultrasound-guided lumbar plexus and sciatic nerve blocks provide longer postoperative analgesia with fewer hemodynamic changes, making them preferable in high-risk or prolonged orthopedic surgeries. Recommendations For lower limb orthopedic surgeries, ultrasound-guided lumbar plexus and sciatic nerve blocks are recommended, particularly in patients at risk of hemodynamic instability or requiring prolonged analgesia.

Translational diffusion of fluorescent probes on a sphere: monte carlo simulations, theory, and fluorescence anisotropy experiment

Translational diffusion of fluorescent molecules on curved surfaces (micelles, vesicles, and proteins) depolarizes the fluorescence. A Monte Carlo simulation method was developed to obtain the fluorescence anisotropy decays for the general case of molecular dipoles tilted at an angle a to the surface normal. The method is used to obtain fluorescence anisotropy decay due to diffusion of tilted dipoles on a spherical surface, which matched well with the exact solution for the sphere. The anisotropy decay is a single exponential for α = 0° , a double exponential for α = 90° , and three exponentials for intermediate angles. The slower decay component(s) for α ≠ 0 arise due to the geometric phase factor. Although the anisotropy decay equation contains three exponentials, there are only two parameters, namely a and the rate constant, Dtr/R2, where Dtr is the translational diffusion coefficient and R is the radius of the sphere. It is therefore possible to determine the orientation angle and translational diffusion coefficient from the experimental fluorescence anisotropy data. This method was applied in interpreting the fluorescence anisotropy decay of Nile red in SDS micelles. It is necessary, however, to include two other independent mechanisms of fluorescence depolarization for molecules intercalated in micelles. These are the wobbling dynamics of the molecule about the molecular long axis, and the rotation of the spherical micelle as a whole. The fitting of the fluorescence anisotropy decay to the full equation gave the tilt angle of the molecular dipoles to be 1± 2° and the translational diffusion coefficient to be 1.3± 0.1×10-10 m2/s

Possible mechanisms of host resistance to Haemonchus contortus infection in sheep breeds native to the Canary Islands

Haemonchus contortus appears to be the most economically important helminth parasite for small ruminant production in many regions of the world. The two sheep breeds native to the Canary Islands display distinctly different resistant phenotypes under both natural and experimental infections. Canaria Hair Breed (CHB) tends to have significantly lower worm burden and delayed and reduced egg production than the susceptible Canaria Sheep (CS). To understand molecular mechanisms underlying host resistance, we compared the abomasal mucosal transcriptome of the two breeds in response to Haemonchus infection using RNAseq technology. The transcript abundance of 711 and 50 genes were significantly impacted by infection in CHB and CS, respectively (false discovery rate <0.05) while 27 of these genes were significantly affected in both breeds. Likewise, 477 and 16 Gene Ontology (GO) terms were significantly enriched in CHB and CS, respectively (P < 1.0 × 10(−4)). A broad range of mechanisms have evolved in resistant CHB to provide protection against the parasite. Our findings suggest that readily inducible acute inflammatory responses, complement activation, accelerated cell proliferation and subsequent tissue repair, and immunity directed against parasite fecundity all contributed to the development of host resistance to parasitic infection in the resistant breed

In Vitro Effect of Porphyromonas gingivalis Methionine Gamma Lyase on Biofilm Composition and Oral Inflammatory Response

Methanethiol (methyl mercaptan) is an important contributor to oral malodour and periodontal tissue destruction. Porphyromonas gingivalis, Prevotella intermedia and Fusobacterium nucleatum are key oral microbial species that produce methanethiol via methionine gamma lyase (mgl) activity. The aim of this study was to compare an mgl knockout strain of P. gingivalis with its wild type using a 10-species biofilm co-culture model with oral keratinocytes and its effect on biofilm composition and inflammatory cytokine production. A P. gingivalis mgl knockout strain was constructed using insertion mutagenesis from wild type W50 with gas chromatographic head space analysis confirming lack of methanethiol production. 10-species biofilms consisting of Streptococcus mitis, Streptococcus oralis, Streptococcus intermedius, Fusobacterium nucleatum ssp polymorphum, Fusobacterium nucleatum ssp vincentii, Veillonella dispar, Actinomyces naeslundii, Prevotella intermedia and Aggregatibacter actinomycetemcomitans with either the wild type or mutant P. gingivalis were grown on Thermanox cover slips and used to stimulate oral keratinocytes (OKF6-TERT2), under anaerobic conditions for 4 and 24 hours. Biofilms were analysed by quantitative PCR with SYBR Green for changes in microbial ecology. Keratinocyte culture supernatants were analysed using a multiplex bead immunoassay for cytokines. Significant population differences were observed between mutant and wild type biofilms; V. dispar proportions increased (p&lt;0.001), whilst A. naeslundii (p&lt;0.01) and Streptococcus spp. (p&lt;0.05) decreased in mutant biofilms. Keratinocytes produced less IL-8, IL-6 and IL-1α when stimulated with the mutant biofilms compared to wild type. Lack of mgl in P. gingivalis has been shown to affect microbial ecology in vitro, giving rise to a markedly different biofilm composition, with a more pro-inflammatory cytokine response from the keratinocytes observed. A possible role for methanethiol in biofilm formation and cytokine response with subsequent effects on oral malodor and periodontitis is suggested