Swimming Period Research Articles

THE IMPACT OF WINTER SWIMMING ON FUNCTIONAL MICROVASCULAR CHANGES

Objective: Microcirculation plays an important role in the development of cardiovascular control. Therefore, the aim of our study was to investigate the impact of winter swimming on functional changes in cutaneous microcirculation Flow-mediated skin fluorescence (FMSF) is a novel and non-invasive technique assessing microvascular function based on the measurements of nicotinamide adenine dinucleotide hydrogen (NADH) fluorescence intensity in the epidermis and post occlusive reactive hyperemia test. NADH intensity changes in response to blockage and release of blood flow in the brachial artery, which corresponds to microvascular function. Design and method: FMSF examinations were performed before and after the winter swimming period lasting from November 2022 to April 2023 in 37 subjects (mean age 46±4,0 years, 65% women). The mean frequency of winter swimming activity was 1,3 times per week. We analysed the following variables: the ischemic response (IRmax and IRindex) – the ratio of relative to baseline maximal increase in fluorescence intensity during cuff occlusion and the hyperaemic response after cuff release (HRmax and HRindex). Flowmotion, measured at baseline (FM) and at reperfusion (FM(R)), reflects flow oscillations. Normoxia oscillatory index (NOI) represents the proportion of endothelial and neurogenic blood flow oscillations in relation to all oscillations detected in low frequency range. The hypoxia sensitivity (HS), measured during reperfusion, reflects the intensity of flowmotion related to myogenic oscillations. Results: The statistical analysis revealed following results according to the winter swimming: Conclusions: Increase in microvascular oscillations denoted by NOI and HS suggests a beneficial impact of winter swimming on cutaneous microcirculation. Improvement in microcirculation performance may partly explain lowering of cardiovascular risk in regular winter swimmers.

Hydrodynamics and scaling laws for intermittent S-start swimming

The hydrodynamics of a self-propelling swimmer undergoing intermittent S-start swimming are investigated extensively with varying duty cycle $DC$ , swimming period $T$ , and tailbeat amplitude $A$ . We find that the steady time-averaged swimming speed $\bar {U}_x$ increases directly with $A$ , but varies inversely with $DC$ and $T$ , where there is a maximal improvement of $541.29\,\%$ over continuous cruising swimming. Our results reveal two scaling laws, in the form of input versus output relations, that relate the swimmer's kinematics to its hydrodynamic performance: swimming speed and efficiency. A smaller $DC$ causes increased fluctuations in the swimmer's velocity generation. A larger $A$ , on the other hand, allows the swimmer to reach steady swimming more quickly. Although we set out to determine scaling laws for intermittent S-start swimming, these scaling laws extend naturally to burst-and-coast and continuous modes of swimming. Additionally, we have identified, categorized and linked the wake structures produced by intermittent S-start swimmers with their velocity generation.

The Effect of Exercise Volume on Depressive-Related Behaviors and Levels of Brain-Derived Neurotrophic Factor and Serum Testosterone Levels

Objective: The aim of the present study was to investigate the effect of training volume on depression-related behaviors and serum levels of brain-derived neurotrophic factor (BDNF) and testosterone in mice. Male NMRI mice, approximately 80 days old and weighing 20 to 23 grams, were used in this study. Methods and Materials: They were kept under a 12-hour light/12-hour dark cycle at a temperature of 23±1°C, with adequate food and water provided. The male NMRI mice, approximately 80 days old and weighing 20 to 23 grams, were kept under a 12-hour light/12-hour dark cycle at a temperature of 23±1°C, with adequate food and water provided. From 90 days old to 118 days old, the animals underwent swimming exercise for 4 weeks. They were divided into two groups: long-term training volume and short-term training volume. The short-term swimming group included one session of short-term training, while the long-term group included three sessions of long-term training with 10-minute swimming periods and 15-minute rest intervals between each session. The water depth and swimming duration gradually increased from 5 to 15 centimeters (second to fourth week) and from 20 (second to third week) to 30 (fourth week) minutes per day. The non-exercised animals were placed in a round tank without water for a duration similar to that of the exercised animals. Results: The results showed a significant difference in immobility duration between the control group and the two training groups, as well as between the two training groups (P ≤ 0.05). There was also a significant difference in depression levels between the two training groups and between the long-term training group and the control group (P ≤ 0.05). However, there was no significant difference between the short-term training group and the control group (P ≥ 0.05). Post hoc test results indicated a significant difference in BDNF levels between the control group and the long-term training group (P ≤ 0.05). Furthermore, there was a significant difference in testosterone levels between the control group and both the short-term and long-term training groups (P ≤ 0.05), but no difference between the two training groups (P ≥ 0.05). Conclusion: Based on the overall results of the study, different training volumes have varying effects on depression and BDNF levels, with long-term training producing greater effects.

Swimming Endurance Capacity of Mice is Increased by Chronic Consumption of Medium-Chain Triglycerides

The effect of chronic administration of medium-chain triglycerides (MCT) on swimming endurance (swim capacity) was investigated in male Std ddY mice. The mice were fed a diet containing 80 g MCT + 20 g long-chain triglycerides (LCT)/kg diet for 6 wk; mice fed diet containing 100 g LCT/kg diet were used as controls. After being accustomed to swimming, the mice were subjected to forced swimming every 2 d in the current water pool that we had developed, and the total swimming period until exhaustion was measured. The total swimming period was used as the index of swim capacity. The group fed MCT showed significantly greater swim capacity than the control group (89.5 ± 2.5 vs. 80.2 ± 2.0 min). In another experiment, after 4 wk of MCT diet consumption, significantly greater swim capacity was found in untrained mice. The major metabolic consequences of the adaptations of muscle to prolonged MCT administration during endurance training were higher activities of 3-oxo acid CoA-transferase (P < 0.01), citrate synthase (P < 0.1) and malate dehydrogenase (P < 0.1). These findings suggest that increases in the enzyme activities of the tricarboxylic acid cycle and ketone body utilization associated with the chronic administration of an MCT-containing diet enhance swim capacity in mice.

Effect of diet on molecular relationships between Atlantic cod larval muscle growth dynamics, metabolism, and antioxidant defense system

We studied molecular effects (RNAseq and qPCR) of first feeding prey types (copepods or rotifers/Artemia) on skeletal muscle myogenesis and growth dynamics (proliferation, differentiation), metabolism (glycolysis, gluconeogenesis, oxidative phosphorylation), and antioxidant defense system (production/regulation of reactive oxygen species (ROS) in cod (Gadus morhua) larval skeletal muscle. Larval somatic growth rates were significantly higher in copepod fed larvae, although shifts in gene expressions related to muscle growth dynamics between hypertrophy and hyperplasia and generation and regulation of ROS mostly occurred around 5-, 10-, and 15-mm standard length (SL) for both groups. Gene expression for cell membrane proteins (such as nox1 and igf1r) peaked at 7 mm SL in all larvae, corresponding with increased ROS expressions in cod muscle during the exponential stratified hyperplasia phase from 7 mm SL. Expression for muscle differentiation (mef2a) occurred continuously (strongest from 10 mm SL). Expressions for muscle proliferation (pcna) and hydrogen peroxide (H2O2) generation (sod1 and sod2) occurred in the 5 - 15 mm SL range, peaking at 10 mm SL in all larvae. A downregulation of sod1 and sod2 in skeletal muscle from 15 mm SL indicated the first response of the defense antioxidant system. Gene expressions related to glucose metabolism (slc2A11, pfk, fpb2, ldha) was 3 - 10 times higher in copepod-fed larvae than in rotifer/Artemia-fed larvae between 7 – 10 mm (live prey period). Copepods move faster than rotifers, and cod larvae will also gradually increase their active swimming periods, due to less viscous forces. Active swimming during the strongest muscle stratified hyperplasia phase (7 – 10 mm SL) could promote a better delivery and transport across the muscle membrane and intracellular flux through glycolysis and oxidative phosphorylation and would contribute to the observed earlier and more effective glucose metabolism in the larvae fed copepods. We suggest that active swimming is an important factor promoting cod larval muscle growth, especially during the strongest muscle hyperplasia phase between 7 and 10 mm SL. The rapid movements of copepods and better nutritional composition could play important roles in stabilizing ROS levels, promoting high swimming activities and enhancing long-term muscle growth in cod.

Swimming Using a Unidirectionally Rotating, Single Stopping Flagellum in the Alpha Proteobacterium Rhodobacter sphaeroides.

Rhodobacter sphaeroides has 2 flagellar operons, one, Fla2, encoding a polar tuft that is not expressed under laboratory conditions and a second, Fla1, encoding a single randomly positioned flagellum. This single flagellum, unlike the flagella of other species studied, only rotates in a counterclockwise direction. Long periods of smooth swimming are punctuated by short stops, caused by the binding of one of 3 competing CheY homologs to the motor. During a stop, the motor is locked, not freely rotating, and the flagellar filament changes conformation to a short wavelength, large amplitude structure, reforming into a driving helix when the motor restarts. The cell has been reoriented during the brief stop and the next period of smooth swimming is a new direction.

Oogenesis and embryogenesis in a cryptogenic species of calcareous sponge (Calcaronea, Heteropiidae) in the southwestern Atlantic

AbstractCalcarea is a diverse group of sponges, in which individuals are generally small and found in cryptic habitats. These characteristics hamper the access to them and, consequently, the knowledge about several aspects of their biology, including reproduction. Little is known about many reproductive aspects of these sponges and broad generalizations are made upon few studied species. Therefore, investigations dealing with the oogenesis and embryogenesis of more species are still necessary. Sycettusa hastifera is an alien species in the southwestern Atlantic. Knowledge about its reproduction would not only help to improve our comprehension of reproduction in Calcaronea but would also help to understand the capacity of this exotic species to colonize. Histological and electron microscopy analyses of individuals sampled at Arraial do Cabo (Rio de Janeiro, Brazil) showed that oogenesis in S. hastifera was long (4–6 months) and nutrients were acquired by association with nurse cells and endocytosis of bacteria, yielding heterogeneous and complex yolk inclusions. Cleavage, inversion, and amphiblastula larvae were similar to what has been observed in other calcaroneans, except for the larval cavity lacking amoeboid cells and the relatively long swimming period of the amphiblastula (on average 12 h, but reaching 72 h). Our results indicate that the vitellogenic mechanism characterized as mixed (an ancestral characteristic of Calcaronea) is strongly influenced by autosynthesis; during cleavage, cell fates could be determined from embryo to larva; and inversion of the embryo (which will become the amphiblastula larva) directly into the choanocyte chamber is an ancestral characteristic of Calcaronea. Despite the absence of amoeboid cells or other structures to nourish the larva, the long swimming period suggests that vitellogenesis is sufficient for the maintenance of the embryo and larva until metamorphosis. This characteristic may facilitate the spread of this cryptogenic species to new regions.

Antidepressant and Anxiolytic Effect of Tramadol as Compared to Imipramine, in Acute and Chronic Dosage in Rats

Objective: To assess the anti-depressant and anxiolytic effect of tramadol as compared to imipramine (approved antidepressant) in acute and chronic doses in rats.Methodology: This observational experimental animal study was carried out from December 2020 to February 2021 at Liaquat University of Medical and Health Sciences (LUMHS) Jamshoro in collaboration with Agricultural University, Tandojam. Forty- eight healthy male rats housed at Animal House Sindh, Agricultural University, Tandojam after due approval from institutional ethical review board. The 48 rats were categorized into 3 equal groups of 16 each: Group A for Normal saline (0.9% NaCl) 15ml/kg, Group B for Imipramine 15 mg/kg and Group C for Tramadol 15 mg/kg. Each group was further subdivided into two groups namely acute A1, B1, C1 and chronic A2, B2, C2 and evaluated for anti-depressant and anxiety activity using forced swim test and elevated plus maze test. The data obtained was analyzed using SPSS. 22.0.Results: Tramadol acted to significantly reduce the mean duration of immobility as compared to the control (P&lt;0.001). Resolution of immobility due to tramadol was insignificant when compared to imipramine. Likewise, the swimming periods in the tramadol and imipramine groups were significantly longer than the control group (&lt;0.001), but almost equal in both tramadol and imipramine groups, showcasing that tramadol has antidepressant activity at par with imipramine (p value &gt;0.05).Conclusion: Tramadol exhibits significant acute and chronic antidepressant and anxiolytic effects in rats when compared to imipramine and controls.

Animal Models of Depression - Chronic Despair Model (CDM).

Major depressive disorder is one of the most prevalent forms of mental illnesses and causes tremendous individual suffering and socioeconomic burden. Despite its importance, current pharmacological treatment is limited, and novel treatment options are urgently needed. One key factor in the search for potential new drugs is evaluating their anti-depressive potency in appropriate animal models. The classical Porsolt forced swim test was used for this purpose for decades to induce and assess a depressive-like state. It consists of two short periods of forced swimming: the first to induce a depressed state and the second on the following day to evaluate the antidepressant effect of the agent given in between the two swim sessions. This model might be suitable as a screening tool for potential antidepressive agents but ignores the delayed onset of action of many antidepressants. The CDM was recently established and represented a modification of the classical test with notable differences. Mice are forced to swim for 5 consecutive days, following the idea that in humans, depression is induced by chronic rather than by acute stress. In a resting period of several days (1-3 weeks), animals develop sustained behavioral despair. The standard read-out method is the measurement of immobility time in an additional delayed swim session, but several alternative methods are proposed to get a broader view of the mood status of the animal. Multiple analysis tools can be used targeting behavioral, molecular, and electrophysiological changes. The depressed phenotype is stable for at least 4 weeks, providing a time window for rapid but also subchronic antidepressant treatment strategies. Furthermore, alterations in the development of a depressive-like state can be addressed using this approach. CDM, therefore, represents a useful tool to better understand depression and to develop novel treatment interventions.

Effects of early exercise training on the severity of autonomic dysreflexia following incomplete spinal cord injury in rodents.

Hemodynamic instability and cardiovascular (CV) dysfunction are hallmarks of patients living with cervical and high thoracic spinal cord injuries (SCI). Individuals experience bouts of autonomic dysreflexia (AD) and persistent hypotension which hamper the activities of daily living. Despite the widespread use of exercise training to improve health and CV function after SCI, little is known about how different training modalities impact hemodynamic stability and severity of AD in a model of incomplete SCI. In this study, we used implantable telemetry devices to assess animals with T2 contusions following 3.5 weeks of exercise training initiated 8 days post‐injury: passive hindlimb cycling (T2‐CYC, n = 5) or active forelimb swimming (T2‐SW, n = 6). Uninjured and non‐exercised SCI control groups were also included (CON, n = 6; T2‐CON, n = 7; T10‐CON, n = 6). Five weeks post‐injury, both T2‐CON and T2‐CYC presented with resting hypotension compared to uninjured CON and T10‐CON groups; no differences were noted in resting blood pressure in T2‐SW versus CON and T10‐CON. Furthermore, pressor responses to colorectal distention (AD) were larger in all T2‐injured groups compared to T10‐CON, and were not attenuated by either form of exercise training. Interestingly, when T2‐injured animals were re‐stratified based on terminal BBB scores (regardless of training group), animals with limited hindlimb recovery (T2‐LOW, n = 7) had more severe AD responses. Our results suggest that the spontaneous recovery of locomotor and autonomic function after severe but incomplete T2 SCI also influences the severity of AD, and that short periods (3.5 weeks) of passive hindlimb cycling or active forelimb swimming are ineffective in this model.

Limber tail syndrome in a Labrador Retriever with confirmed hypothyroidism

AbstractA 4‐year‐old, female, neutered Labrador Retriever was referred with tail flaccidity of acute onset after an extensive period of swimming. There were no other neuromuscular clinical signs on physical examination and no pain of tail palpation. Comorbidity was reported, with previous diagnosis of hypothyroidism (9 months before), but the disease was considered controlled since levothyroxine supplementation. Despite the impossibility to confirm nonrelated neuromuscular impairment associated with hypothyroidism, the fast resolution of clinical signs without intervention was more likely to confirm a limber tail syndrome rather than an endocrine neuromyopathy, but, to the authors' knowledge, this is the first report of its kind, and further investigations are required.

Impact of sperm density on fertilization, hatching and emergence rate of hybrid yellow catfish &amp;quot;Huangyou-1&amp;quot; (&amp;lt;italic&amp;gt;Pseudobagrus vachelli&amp;lt;/italic&amp;gt;♂ &amp;times;&amp;lt;italic&amp;gt;Pelteeobaagrus fulvidraco&amp;lt;/italic&amp;gt;♀)

In order to study the effects of different sperm densities of <italic>Pelteobagrus vachelli</italic> on the fertilization rate, hatching rate and emergence rate of hybrid yellow catfish Huangyou-1, this paper adopted 8 groups of different sperm densities (1×10³-1×10⁶ cells·mL^-1) to carry out artificial insemination experiments. The fertilized eggs were hatched under the same environmental conditions until the out-of-the-membrane fry developed and started to feed during the parallel swimming period. The hatching water temperature was (27±1) ℃ and each gradient was repeated in three groups.Results showed that when the sperm density increased from 1×10³ cells·mL^-1 to 2.5×10⁴ cells·mL^-1, the fertilization rate, hatching rate and emergence rate all increased significantly (<italic>P</italic><0.05); when the sperm density was 5×10⁴ cells·mL^-1, the fertilization rate reached the maximum value of (88.8±2.0) %; when the sperm density was 2.5×10⁴ cells·mL^-1, the hatching rate and emergence rate reached the maximum, respectively (83.4±2.8) % and (79.4±4.6)%. In addition, the regression equation was established to determine the relationship between sperm density and fertilization rate, hatching rate and emergence rate. In this experiment, 8 different sperm densities (1×10³-1×10⁶ cells·mL^-1) were used to artificially inseminate hybrid yellow catfish, and the optimal sperm density was determined. It is recommended that the sperm density range of 2.5×10⁴-5×10⁴ cells·mL^-1 should be used for artificial insemination in actual production. This density uses less sperm than in actual production, which can effectively protect male gamete resources and reduce the demand for cryopreservation of sperm during artificial seed production. The optimal sperm density selected in this experiment can be used as the best choice in large-scale production of hybrid yellow catfish, and it can also provide certain references for artificial insemination and hybrid breeding of yellow catfish.

Uji Efek Stimulansia Ekstrak Etil Asetat Kulit Kayu Akway (Drymis piperita) Asal Papua Pada Tikus (Ratus norvegicus) Jantan

Drymis sp. stem bark from Papua widely utilized by local people especially in Sougb Tribe from Sururey Distric Pegunungan Arfak West Papua, one of them is used to increase the stamina of the body. The aim of this study was to investigate the tonic effect of Drymis sp. stem bark of Ratus norvegicus. Ratatory exhaustion method was used to the tonic effect. Selected rats (30) were divided into 6 groups, each consisting of 5 rats. Tested extract was administrated oraly one dose to the rats. Group I, II and III was given the ethil acetat fraction of Drymis sp. stem bark 10mg/kg body weight, 30mg/kg body weight and 50mg/kg body weight consecutively. Group IV was given CMC-Na 0,5% (as negative control). Goup V was given caffein 15 mg/kg body weight (as positive control) and Group VI as a control. The total swimming period until exhaustion was measured and use as index of swimming capacity. Research result show that the highest dose 50 mg/body weight of the tested fraction the longer swimming time and with better stamina. The result of One Way ANOVA test showed that there was a significant difference between treatment group, followed by tukey test, tukey result obtained the ethil acetat fraction and negative control (CMC Na) showed that there was significant difference, and there is no real difference between between treatment group and positive control.   Key words: Drymis sp, Papua, tonic effect, rats. Â

Previous adaptation triggers distinct molecular pathways and modulates early and long-term neuroprotective effects of pregnancy swimming preventing neonatal hypoxia-ischemia damage in rats

Neonatal hypoxia-ischemia (HI) is one of the main causes of neurological damage in newborns. Pregnancy swimming (PS) alters brain maturation and has neuroprotective effects following HI; however, variables such as timing play a decisive role in its effects. Prior to mating, we tested if adaptation of female rats to a tank filled with water at 32 °C for 7 days before mating, modulates PS benefits. After mating, rats swam 20 min/day or remained in standard cages. Seven-day-old pups were subjected to HI (right common carotid artery occlusion followed by FiO2 8% for 60 min). Animals were divided into 8 experimental groups, adaptation, swimming and injury. Astrocytic reactivity, apoptosis-related proteins, neurotrophins and cell survival markers expression were assessed in the hippocampus 24 h after HI. From PND45, animals performed behavioral tests followed by histological assessment. Three-way ANOVA showed a significant increase in astrogliosis only in non-adapted HI animals. Swimming decreased apoptotic cell death despite adaptation period in both exercised groups. Cylinder evidenced HI impairments; no effect of swimming or adaptation period were observed. In the open field, only HI animals whose mothers had been adapted had increased locomotion; moreover, swimming reversed HI damage. Hemisphere and hippocampus were preserved only in the HI group whose mothers swam before mating, suggesting a preconditioning effect mediated by the adaptation. In summary, adaptation period plays a major role in the mechanisms involving neuroprotection afforded by PS and needs to be further explored in future studies involving damage to the neonatal brain.

Physical exercise modifies behavioral and molecular parameters related to opioid addiction regardless of training time

Addiction is a devastating worldwide disorder that requires effective and innovative therapies. Physical exercise could be useful in addiction treatment because it shares a common neural circuit with addictive drugs. Based on this, molecular adaptations consequent to time of exercise in opioid exposed animals were evaluated. Rats were designed as sedentary (SED) or exercised (EXE). This last group was separated to perform three different periods of swimming: short-term (S-EXE), medium-term (M-EXE) and long-term (L-EXE) for 14, 28 and 42 days, respectively. On the last exercising week, one-half of the animals from SED and all animals from S-, M- and l-EXE were concomitantly exposed to morphine-conditioned place preference (CPP) paradigm and y-maze task for behavioral assessments followed by molecular assays in both Nucleus accumbens (NAc) and hippocampus. Between SED groups, morphine conditioning showed drug-CPP and increased dopamine transporter (DAT), dopamine receptor type-1 (D1R), type-2 (D2R) and glucocorticoid receptor (GR) in both brain areas in relation to saline group. Besides the small morphine-CPP in relation to SED group, all periods decreased DAT, D1R, and GR immunoreactivity in NAc, DAT and D1R in hippocampus, while D2R in both brain areas and GR in hippocampus were primarily decreased by L-EXE. Our findings show that even a short-term exercise modifies behaviors related to drug withdrawal, changing DA targets and GR, which are closely linked to addiction. Therefore, our outcomes involving physical exercise are interesting to perform a possible clinical trial, thus expanding the knowledge about drug addiction.

Ci-hox12 tail gradient precedes and participates in the control of the apoptotic-dependent tail regression during Ciona larva metamorphosis

At the onset of the Ciona intestinalis metamorphosis, the first event is tail regression characterized, by a contraction, an apoptotic wave and Primordial Germ Cells (PGC) movement. All these cell behaviors originate from the posterior tail tip and progress to the anterior. Interestingly, earlier in Ciona development, the antero-posterior (A/P) patterning of the tailbud epidermis depends on two antagonist gradients, respectively FGF/MAPK at the posterior and retinoic acid (RA) at the anterior part of the tail. Fundamental genes such as Ci-hox1, Ci-hox12 and Ci-wnt5, classically involved in chordates A/P polarity and patterning, are controlled by these gradients and exhibit specific expression profiles in the tail epidermis. In this study, we first confirmed by video-microscopy that tail regression depends on a postero-anterior wave of a caspase-dependent apoptosis coupled with a contraction event. Concomitantly an apoptotic-dependent postero-anterior movement of PGC was observed for the first time. Unexpectedly, we observed that expression of the posterior hox gene, Ci-hox12, was extended from a posterior localization to the entire tail epidermis as the larvae progress from the swimming period to the settlement stage. In addition, when we disturbed FGF/MAPK or RA gradients we observed strong effects on Ci-hox12 expression pattern coupled with modulation on the subsequent tail regression dynamics. These results support the idea that Ci-hox12 expression in larval tail precedes and participates in the regulation of the postero-anterior cell behavior during the subsequent tail regression.

The behavior of the Argentine shortfin squid (Illex argentinus) exposed to bottom trawl gear off southern Brazil

The behavior of the Argentine shortfin squid ( Illex argentinus ) in reaction to a trawl net is reported from images obtained during one fishing tow operated by a commercial trawler in May 2015 in slope grounds off southern Brazil (depth 370-361 m; 33°37’S, 50°49’W). Video analysis utilized criteria to classify the horizontal and vertical distribution of squid in the field of view of the camera, posture (pitch and yaw), squid color patterns, escape reaction, swimming time and use of the tail fin. The monitored bottom trawl operation intercepted dense and patchily distributed schools of I. argentinus that could be observed for brief periods of time swimming ahead of the mouth of the trawl. Individuals were evenly distributed in the water column but concentrated on the center and right sectors of the trawl mouth. Most squids in the path of a trawl tended to swim by jet-propulsion for 10-20 s, tail-first and with regularly spaced fin flaps. Estimated speed (1.24 m s -1 ) was higher than cruise speed recorded for other ommastrephid squids in nature (0.3 m s -1 ), possibly reflecting an emergency escape reaction. After a period of sustained swimming ahead of the trawl, squid reacted in different ways including: a) slowing down and swimming into the net tunnel, b) shifting directions to escape through the trawl mouth sides, and c) swimming up, trying to escape over the top trawl panel, sometimes turning around pointing the tail towards the trawl mouth.

Antidepressant activity of 4-amino-5-(alkyl-, aryl-, heteryl)-1,2,4-triazole-3-thione benzylidene derivatives

The current market for antidepressants has a number of limitations, they have a high probability of development of adverse reactions, have low latitude and stability of the therapeutic effect, and also have a long latent period of action. Therefore, it seems obvious that there is a need to create new drugs that improve the quality of life, affect the mood and are safe. An analysis of literary sources has shown that derivatives of 1,2,4-triazole have a pronounced antidepressant effect and drugs such as Trazodone and Alprozalam are widely used in medical practice. The purpose of this work was to study antidepressant effects of 1,2,4-triazole derivatives and to make analysis of the dependence between chemical structure and pharmacological activity. Materials and methods. The search of antidepressants in the series of 1,2,4-triazole derivatives was performed on the basis of the classical model of R.D. Porsolt in the modification of E.V. Schetynin. Each animal was immersed for 6 minutes in a vessel filled with water at a temperature of 27 °C. The duration of active swimming was fixed (vigorous movements of all paws with active movement), passive swimming (weak bends of the paws necessary to support the body to swim) and immobilization (no swimming motions). In addition, the number of active swimming periods of different lengths and the number of very short immobilization periods of up to 6 seconds were counted. The index of depression (ID) was calculated due to the ratio of the very short periods number of immobilization to the total number of active swimming periods. The research results are processed by modern statistical methods of analysis using personal computer, including the standard program package Microsoft Office 2013 (Microsoft Excel) and Statistica ® for Windows 6.0. The average arithmetic mean (M) and standard mean errors (±m) were calculated. The statistical significance of intergroup differences according to the experimental data was established using Student's t-criterion. To study the dependence of the influence of benzylidene derivatives of 4-amino-5-(alkyl-, aryl-, heteryl)-2,4-dihydro-3H-1,2,4-triazole-3-thione on the duration of passive swimming and the duration of immobilization was carried out by correlation analysis. Results. Benzylidene derivatives of 4-amino-5-(alkyl-, aryl-, heteryl)-1,2,4-triazole-3-thione were used as test substances. The index of depression in the use of fluoxetine decreased to 70.92 % (P < 0.05), and with the use of trazodone to 76.95 % (P < 0.05). Compounds 26 and 32 statistically significantly lowered the index of depression to 86.66 and 81.24 %, respectively, which was higher than the activity of the used comparison drugs. The main indicator of rats despair was the duration of immobilization, decreased to 73.53 % (P < 0.05) and trazodone to 79.55 (P < 0.05) when administered with fluoxetine. When applying 1,2,4-triazole derivatives, the duration of immobilization of compound 32 was reduced to 89.53 % (P < 0.05), and compounds 23 to 87.05 % (P < 0.05). Conclusions. The most active compound according to the results of the study was compound 32, which reduced the average duration of immobilization in the experimental group to 89.53 % and had a rather low index of depression (0.34 ± 0.08, P < 0.05).

Morphological evidence of anabolic action of the drug histochrome in rats

The aim of the investigation was to assess histochrome’s anabolic effect as a consequence of treatment of various doses in rats in conditions of prolonged physical training. Materials and methods . The experiments were performed on the Wistar’s rats. Experimental Group 1 was subcutaneously injected with histochrome in a dose of 1 mg/kg (n = 20) within 10 days, experimental group 2 was treated subcutaneously at a dose of 10 mg/kg (n = 20), and control group 3 received equivolume injections of isotonic sodium chloride (n = 20). Rat musclehypertrophy was induced using the method of forced swimming. A piece ofmuscle was takenfor morphological examination a day after the first and last period of swimming. Hypertrophy of muscle fibers was evaluated by the cross-sectional diameter of muscle fibers, the average quantity of argyrophilic nucleolar organizer region (AgNOR) proteins and the percentage of nuclei with 1, 2, 3 or more AgNOR compared to intact (control) animals. Results. Microscopic morphological examination of M. gastrocnemius registered increase in diameter of muscle fiber by 19,4% (1 mg/kg) and by 60% (10 mg/kg). In the control group of rats an increase in a transverse section of muscle fibers was not found to be statistically significant. The study of biosynthetic nuclei activity of myosimplastus registered increase the AgNOR proteins in both examines groups of animals in comparison the less dynamics in control one. By 10th day of observation the quantity of myosimplastus with two AgNOR increased in a control group of rats by 10%. The maximum AgNOR proteins gained was marked in case of the prolonged use of histochrome in a dose 1 mg/kg. Conclusion. Histochrome enables the increase in dose-dependent biosynthetic processes in skeletal muscles of rats, providing the development of anabolic effect.

Changes in the flagellar bundling time account for variations in swimming behavior of flagellated bacteria in viscous media

Although the motility of the flagellated bacteria, Escherichia coli, has been widely studied, the effect of viscosity on swimming speed remains controversial. The swimming mode of wild-type E. coli is often idealized as a run-and-tumble sequence in which periods of swimming at a constant speed are randomly interrupted by a sudden change of direction at a very low speed. Using a tracking microscope, we follow cells for extended periods of time in Newtonian liquids of varying viscosity and find that the swimming behavior of a single cell can exhibit a variety of behaviors, including run and tumble and "slow random walk" in which the cells move at a relatively low speed. Although the characteristic swimming speed varies between individuals and in different polymer solutions, we find that the skewness of the speed distribution is solely a function of viscosity and can be used, in concert with the measured average swimming speed, to determine the effective running speed of each cell. We hypothesize that differences in the swimming behavior observed in solutions of different viscosity are due to changes in the flagellar bundling time, which increases as the viscosity rises, due to the lower rotation rate of the flagellar motor. A numerical simulation and the use of resistive force theory provide support for this hypothesis.