Hybrid peony (<Emphasis Type="Italic">Paeonia hybrida</Emphasis> Pall.), a rare endangered plant of Bashkir Trans-Uralian region: Autocorrelation analysis of the spatial genotype distribution under different environmental conditions

Hybrid peony (Paeonia hybrida Pall.) is listed as endangered in Russian Federation (since 1988) and in several regions of Russia. The structure of the isolated population from Bashkir Trans-Uralian region, separated by 1500 km from the main geographic range of this species, has been studied using isoenzyme markers from 11 loci. The population is split between two geographical locations, both characterized by a relatively high genetic diversity (mean allele number A = 1.9±0.3, percentage of polymorphic loci P = 0.54, observed heterozigosity H _O = 0.223±0.068, expected heterozigosity H _E = 0.229±0.067) and a quite low intergroup genetic differentiation (fixation index F _ST = 0.008, Nei’s genetic distance D = 0.011). In a subpopulation located near a swampy lake in dense cereal grass and steppe shrubby vegetation, autocorrelation analysis has revealed spatial structuring of genetic variability. In the other location, a stipa-forb steppe on a flat hill slope, a uniform spatial structure of the genotypes has been observed. The results are discussed with respect to the ecological characteristics of the species and the conservation of the genetic pool of the population in situ and ex situ.     

The role of the ovarian horn locus in regulation of spontaneous electric activity of myometrial rhythmogenic areas

The role of the ovarian area of the uterine horn in coordination of spontaneous activity of myometrial rhythmogenic areas was studied in nonpregnant rats both under normal conditions and following transection of the uterine horn in its middle part to isolate the ovarian locus from the distally located uterine active areas. The effect of oxytocin as a factor that reveals a leading role of the ovarian locus in synchronization of myometrial spontaneous activity was studied under the above conditions. Intravenous oxytocin administration (10^–1 μg/kg) under normal conditions promotes a considerable increase in the peak amplitude and mean rise rate in all the three rhythmogenic areas (%; ovarian horn area—by 148.63 ± 6.1, p ≤ 0.001 and 141.04 ± 7.6, p ≤ 0.01; cervical horn area—by 143.85 ± 3.5, p ≤ 0.001 and 146.89 ± 8.5, p ≤ 0.001; uterine corpus—by 146.20 ± 7.2, p ≤ 0.001 and 139.73 ± 8.2, p ≤ 0.05, respectively). Under the same conditions, also there is a similar increase in the active state duration in all the three areas (%; 132.70 ± 4.5, p ≤ 0.05; 124.90 ± 9.6, p ≤ 0.05; 128.03 ± 7.2, p ≤ 0.05, respectively). Following transection of the uterine horn, oxytocin administration causes an increase in all the three activity indicators only in the ovarian horn area (%; 134.86 ± 2.5, p ≤ 0.05; 139.49 ± 4.5, p ≤ 0.001; 123.8 ± 7.3, p ≤ 0.05, respectively). In the cervical horn area and uterine corpus, no appreciable changes in these indicators were detected under both conditions. We believe that the ovarian locus is involved in coordination of activities of all the three myometrial rhythmogenic areas as revealed by oxytocin.     

Biological Data on <Emphasis Type="Italic">Anovia punica</Emphasis> Gordon (Coleoptera: Coccinellidae), a Predator of <Emphasis Type="Italic">Crypticerya multicicatrices</Emphasis> Kondo &amp; Unruh (Hemiptera: Monophlebidae)

The coccinellid beetle Anovia punica Gordon (Coleoptera: Coccinellidae: Noviini) is an important predator of the Colombian fluted scale, Crypticerya multicicatrices Kondo & Unruh (Hemiptera: Monophlebidae). In order to gather information on the biological traits of A. punica, we conducted a series of studies, including of the developmental time of each life history stage, estimation of life table parameters, and predation rates under laboratory conditions [25.1 ± 1.6°C, with 70.5 ± 7.3% RH, and natural light regime, approx. 12:12 (L:D) h]. Developmental stages of A. punica were categorized as follows: egg stage, four larval instars, prepupal instar, pupal instar, and adult. Developmental time from egg to adult emergence averaged 29.41 ± 1.85 days, and 47.6% of the eggs developed to adulthood. Female and male survival was 94.42 and 90 days, respectively. Life table parameters show that one female of A. punica is replaced by 86 females (R ₀), the intrinsic growth rate (r _m ) was 0.1115, the average generation time (T) was 40 days, and the doubling time (D _t ) was 6.2 days. The life table parameters suggest that A. punica can be used as a potential predator of C. multicicatrices and, more importantly, provided baseline information for a mass-rearing protocol. This is the first detailed study on the biology of A. punica that reports the potential of this predator as a biological control agent for scale insects of the tribe Iceryini.     

Kinetic characterization of a novel acid ectophosphatase from <Emphasis Type="Italic">Enterobacter asburiae</Emphasis>

Expression of acid ectophosphatase by Enterobacter asburiae, isolated from Cattleya walkeriana (Orchidaceae) roots and identified by the 16S rRNA gene sequencing analysis, was strictly regulated by phosphorus ions, with its optimal activity being observed at an inorganic phosphate concentration of 7 mM. At the optimum pH 3.5, intact cells released p-nitrophenol at a rate of 350.76 ± 13.53 nmol of p-nitrophenolate (pNP)/min/10⁸ cells. The membrane-bound enzyme was obtained by centrifugation at 100,000 × g for 1 h at 4°C. p-Nitrophenylphosphate (pNPP) hydrolysis by the enzyme follows “Michaelis-Menten” kinetics with V = 61.2 U/mg and K_0.5 = 60 μM, while ATP hydrolysis showed V = 19.7 U/mg, K_0.5 = 110 μM, and n_H = 1.6 and pyrophosphate hydrolysis showed V = 29.7 U/mg, K_0.5 = 84 μM, and n_H = 2.3. Arsenate and phosphate were competitive inhibitors with Ki = 0.6 mM and K_i = 1.8 mM, respectively. p-Nitrophenyl phosphatase (pNPPase) activity was inhibited by vanadate, while p-hydroxymercuribenzoate, EDTA, calcium, copper, and cobalt had no inhibitory effects. Magnesium ions were stimulatory (K_0.5 = 2.2 mM and n_H = 0.5). Production of an acid ectophosphatase can be a mechanism for the solubilization of mineral phosphates by microorganisms such as Enterobacter asburiae that are versatile in the solubilization of insoluble minerals, which, in turn, increases the availability of nutrients for plants, particularly in soils that are poor in phosphorus.     

Population genetic structure of <Emphasis Type="Italic">Helix pomatia</Emphasis> L. (Mollusca,Pulmonata) from the southeastern and eastern parts of the range

On the basis of the analysis of genetic variation detectable by ISSR-PCR, the state of the gene pools of 14 populations of Roman snail Helix pomatia L. in the conditions of urbanized landscapes of the southeastern and eastern parts of the current range was examined. According to the data obtained, the majority of the studied populations of this mollusk are in satisfactory condition. This is evidenced by the increased level of genetic diversity (H _e = 0.199 ± 0.025, I _sh = 0.306 ± 0.035) and the high values of effective population size, calculated, on the basis of the straight-line regression equation, between the pairwise genetic and geographic distances (Ne = 2.0–4.9) that are comparable with indigenous common species of terrestrial mollusks. Despite the high level of differentiation (G_st = 0.255, Φ_st = 0.233, N _m = 0.822), the population distribution was not random (R _m =–0.591, p = 0.0004) and corresponded to the model of isolation by distance. It is hypothesized that, in the adventitious colonies of this mollusk, effective formation of a balanced genetic structure takes place that, in the context of biological and ecological features, facilitates its adaptation to the conditions of an urban environment and the population of the new territories of Eastern Europe.     

The Influences of Chromium Supplementation on Glycemic Control,Markers of Cardio-Metabolic Risk,and Oxidative Stress in Infertile Polycystic ovary Syndrome Women Candidate for In vitro Fertilization: a Randomized,Double-Blind,Placebo-Controlled Trial

This study was carried out to investigate the effects of chromium intake on glycemic control, markers of cardio-metabolic risk, and oxidative stress in infertile polycystic ovary syndrome (PCOS) women candidate for in vitro fertilization (IVF). This randomized double-blind, placebo-controlled trial was done among 40 subjects with infertile PCOS candidate for IVF, aged 18–40 years old. Individuals were randomly allocated into two groups to take either 200 μg/day of chromium (n?=?20) or placebo (n?=?20) for 8 weeks. Biochemical parameters were assessed at baseline and at end-of-trial. Compared with the placebo, taking chromium supplements led to significant reductions in fasting plasma glucose (??2.3?±?5.7 vs. +?0.9?±?3.1 mg/dL, P?=?0.03), insulin levels (??1.4?±?2.1 vs. +?0.4?±?1.7 μIU/mL, P?=?0.004), homeostatic model of assessment for insulin resistance (??0.3?±?0.5 vs. +?0.1?±?0.4, P?=?0.005), and a significant increase in quantitative insulin sensitivity check index (+?0.004?±?0.008 vs. ??0.001?±?0.008, P?=?0.03). In addition, chromium supplementation significantly decreased serum triglycerides (??19.2?±?33.8 vs. +?8.3?±?21.7 mg/dL, P?=?0.004), VLDL- (??3.8?±?6.8 vs. +?1.7?±?4.3 mg/dL, P?=?0.004) and total cholesterol concentrations (??15.3?±?26.2 vs. ??0.6?±?15.9 mg/dL, P?=?0.03) compared with the placebo. Additionally, taking chromium supplements was associated with a significant increase in plasma total antioxidant capacity (+?153.9?±?46.1 vs. ??7.8?±?43.9 mmol/L, P?<?0.001) and a significant reduction in malondialdehyde values (?0.3?±?0.3 vs. +?0.1?±?0.2 μmol/L, P?=?0.001) compared with the placebo. Overall, our study supported that chromium administration for 8 weeks to infertile PCOS women candidate for IVF had beneficial impacts on glycemic control, few variables of cardio-metabolic risk, and oxidative stress.     

Characteristic of Polysaccharide Complexes from <Emphasis Type="Italic">Centaurea scabiosa</Emphasis> L. and <Emphasis Type="Italic">Centaurea pseudomaculosa</Emphasis> Dobrocz.

We characterized polysaccharide complexes from Centaurea scabiosa L. and Centaurea pseudomaculosа Dobrocz. We proposed the technique of sequential selection of water-soluble polysaccharides and pectin substances from the aerial parts of studied objects. We have discovered that the content of water-soluble polysaccharides in the aerial parts of C. scabiosa was 2.8 times higher (2.7 ± 0.3%, n = 3) than in C. pseudomaculosа (0.97 ± 0.50%, n = 3). The content of pectin substances in the aerial parts of C. scabiosa was 2 times higher (7.6 ± 0.4%, n = 3) than in C. pseudomaculosа (3.9 ± 0.3%, n = 3). The residues of D-galacturonic acid, L-rhamnose, D-xylose, D-mannose, D-glucose, and D-galactose are the monomeric units of polysaccharide complexes from C. scabiosa and C. pseudomaculosa. Using ion-exchange chromatography, three polysaccharide fractions (molecular weights 667, 722, and 1027 kDa), whose monomer units are D-galacturonic acid, L-rhamnose, D-galactose, D-xylose, and D-glucose were isolated from the water-soluble polysaccharides of C. scabiosa.     

Catalytic properties of aminoacylase of strain <Emphasis Type="Italic">Rhodococcus armeniensis</Emphasis> AM6.1

Studies of substrate specificity revealed that the D-aminoacylase of Rhodococcus armeniensis AM6.1 strain exhibits absolute stereospecificity to the D-stereoisomers of N-acetyl-amino acids. The enzyme is the most active reacted with N-acetyl-D-methionine, as well as with aromatic and hydrophobic N-acetylamino acids and interacts weakly with the basic substrates. It is practically not reacted with acidic and hydrophilic N-acetyl-amino acids. Michaelis constants (K_m) and maximum reaction velocities (V_max) were calculated, using linear regression analysis, for the following substrates: N-acetyl-D-methionine, N-acetyl-D-alanine, N-acetyl-D-phenylalanine, N-acetyl-D-tyrosine, N-acetyl-D-valine, N-acetyl-D-oxyvaline, N-acetyl- D-leucine. Substrate inhibition of D-aminoacylase was displayed with N-acetyl-D-leucine (K_s = 35.5 ± 28.3 mM) and N-acetyl-DL-tyrosine (K_s = 15.8 ± 4.5 mM). Competitive inhibition of the enzyme with product–acetic acid (K_i = 104.7 ± 21.7 mM, K_m = 2.5 ± 0.5 mM, V_max = 25.1 ± 1.5 U/mg) was observed.     

Polymorphism (353)R&gt;Q of gene of blood clotting factor VII and plasma hemostasis

A comparative estimation was conducted to assess the prevalence of genotypes and alleles of the R>Q(353) polymorphism of the coagulation factor FVII gene between a group of the Russian adolescents with essential arterial hypertension and a group of Russian adolescents without such health problems. The RR genotype was diagnosed in 55 adolescents (75.34%) of the control group and in 99 adolescents (84.61%) of the adolescents suffering from essential arterial hypertension (χ² = 1.949, p = 0.163). The R allele frequency was, respectively, 85.62 and 91.88% (χ² = 3.110, p = 0.078). The role of the FVII gene in the determination of the F7 plasma activity was defined in adolescents with essential arterial hypertension and holders of different alleles. Holders of the R allele had significantly higher activity of coagulation factor F7 (97.66 ± 15.48 against 83.37 ± 15.16, p = 0.002), factor F2 (107.45 ± 6.03 against 103.75 ± 6.81, p = 0.023), and antithrombin III (104.47 ± 15.54% against 95.87 ± 11.30%, p = 0.024). than holders of the Q allele. This relationship was not found in adolescents of the control group.     

The effect of losartan therapy on ventricular function in Marfan patients with haploinsufficient or dominant negative <Emphasis Type="Italic">FBN1</Emphasis> mutations

Background

Mild biventricular dysfunction is often present in patients with Marfan syndrome. Losartan has been shown to reduce aortic dilatation in patients with Marfan syndrome. This study assesses the effect of losartan on ventricular volume and function in genetically classified subgroups of asymptomatic Marfan patients without significant valvular regurgitation.

Methods

In this predefined substudy of the COMPARE study, Marfan patients were classified based on the effect of their FBN1 mutation on fibrillin-1 protein, categorised as haploinsufficient or dominant negative. Patients were randomised to a daily dose of losartan 100 mg or no additional treatment. Ventricular volumes and function were measured by magnetic resonance imaging at baseline and after 3 years of follow-up.

Results

Changes in biventricular dimensions were assessed in 163 Marfan patients (48?% female; mean age 38 ± 13 years). In patients with a haploinsufficient FBN1 mutation (n = 43), losartan therapy (n = 19) increased both biventricular end diastolic volume (EDV) and stroke volume (SV) when compared with no additional losartan (n = 24): left ventricular EDV: 9 ± 26 ml vs. ?8 ± 24 ml, p = 0.035 and right ventricular EDV 12 ± 23 ml vs. ?18 ± 24 ml; p < 0.001 and for left ventricle SV: 6 ± 16 ml vs. ?8 ± 17 ml; p = 0.009 and right ventricle SV: 8 ± 16 ml vs. ?7 ± 19 ml; p = 0.009, respectively. No effect was observed in patients with a dominant negative FBN1 mutation (n = 92), or without an FBN1 mutation (n = 28).

Conclusion

Losartan therapy in haploinsufficient Marfan patients increases biventricular end diastolic volume and stroke volume, furthermore, losartan also appears to ameliorate biventricular filling properties.

     

Occupancy modeling of <Emphasis Type="Italic">Parnassius clodius</Emphasis> butterfly populations in Grand Teton National Park,Wyoming

Estimating occupancy patterns and identifying vegetation characteristics that influence the presence of butterfly species are essential approaches needed for determining how habitat changes may affect butterfly populations in the future. The montane butterfly species, Parnassius clodius, was investigated to identify patterns of occupancy relating to habitat variables in Grand Teton National Park and Bridger-Teton National Forest, Wyoming, United States. A series of presence–absence surveys were conducted in 2013 in 41 mesic to xeric montane meadows that were considered suitable habitat for P. clodius during their flight season (June–July) to estimate occupancy (ψ) and detection probability (p). According to the null constant parameter model, P. clodius had high occupancy of ψ?=?0.78?±?0.07 SE and detection probability of p?=?0.75?±?0.04 SE. In models testing covariates, the most important habitat indicator for the occupancy of P. clodius was a strong negative association with big sagebrush (Artemisia tridentata; β = ??21.39?±?21.10 SE) and lupine (Lupinus spp.; β?=???20.03?±?21.24 SE). While P. clodius was found at a high proportion of meadows surveyed, the presence of A. tridentata may limit their distribution within montane meadows at a landscape scale because A. tridentata dominates a large percentage of the montane meadows in our study area. Future climate scenarios predicted for high elevations globally could cause habitat shifts and put populations of P. clodius and similar non-migratory butterfly populations at risk.     

Genetic diversity of the house mouse <Emphasis Type="Italic">Mus musculus</Emphasis> and geographic distribution of its subspecies-specific RAPD markers on the territory of Russia

Genetic diversity and geographic distribution of taxon-specific RAPD markers was examined in ten local populations of the house mouse Mus musculus (n = 42). The house mice were generally characterized by moderate genetic variation: polymorphism P ₉₉ = 60%, P ₉₅ = 32.57%; heterozygosity H = 0.12; the observed allele number n _a = 1.6; the effective allele number n _e = 1.18; the within-population differentiation ?_s = 0.388; and Shannon index I = 0.19. The degree of genetic isolation of individual local populations was greatly variable. The genetic subdivision index G _st varied from 0.162 to 0.770 at the gene flow of Nm = 2.58?0.149, while the among-population distances D _N varied from 0.026 to 0.178. The largest part of the genetic diversity was found among the populations (H _T = 0.125), while the within-population diversity was twice lower (H _S = 0.06). The samples examined were well discriminated relative to the sets of RAPD markers. The character distribution pattern provided conditional subdivision of the mice into the “western” and the “eastern” groups with the putative boarder along the Baikal Lake. The first group was characterized by the prevalence of the markers typical of M. m. musculus and M. m. domesticus. The second group was characterized by the prevalence of the markers typical of M. m. musculus, M. m. gansuensis, M. m. castaneus, M. m. domesticus, and M. m. wagneri. The genotype of the nominative subspecies M. m. musculus was background for all populations. In the populations examined some of earlier described subspecies-specific molecular markers were found at different frequencies, pointing to the involvement of several subspecies of M. musculus in the process of hybridization.     

Influence of Different Rice Cultivars on <Emphasis Type="Italic">Schizotetranychus oryzae</Emphasis> Development

Schizotetranychus oryzae Rossi de Simons (Acari: Tetranychidae) is considered one of the most important phytophagous mite in rice cultivation in the Americas South, Central, and North. This study aimed to examine some biological aspects of S. oryzae developing on leaves of three different cultivars of rice [Oryza sativa (L.)—Poaceae] produced in the state of Rio Grande do Sul, Brasil. The plants were kept in a room at 25?±?1°C, with natural light (photophase of approximately 14 h) and 70?±?5% relative humidity. During the immature stages, observations were carried out daily at 7 am, 1 pm, and 7 pm. The results showed that the mean duration of the egg–adult period in days were similar between cultivars evaluated (Irga 424, 11.27?±?0.13; Taim, 11.21?±?0.14 and Sinuelo, 11.13?±?0.15). Egg–adult viability on Irga 424, Sinuelo, and Taim was 61.9, 85.71, and 90.48%, respectively, being lowest on Irga 424 (χ2?=?28.62, p?<?0.0001). The duration of the immature stages was not affected by cultivar, but on Irga 424, egg–adult viability and female longevity were lower. The results of this study can help select O. sativa cultivar resistant to S. oryzae. However, historically, the IRGA 424 has lower populations of S. oryzae in field conditions.     

Association analysis of alcohol metabolizing enzymes <Emphasis Type="Italic">ADH1B,ADH7, CYP2E1</Emphasis> gene polymorphism with risk for coronary atherosclerosis

The allele and genotype distribution of two alcohol dehydrogenase genes ADH1B (exon 3 polymorphism A/G (47His)), ADH7 (intron 5 polymorphism G/C) and cytochrome P450 2E1 gene (CYP2E1; 5′-flanking region G/C and intron 6 T/A polymorphisms) were examined in Russian (Tomsk, n = 125) healthy population and in coronary atherosclerosis patients (CA, n = 92). The genotype frequencies followed the Hardy-Weinberg equilibrium and the alleles were in linkage equilibrium or gametic equilibrium in the control sample. Only two CYP2E1 gene polymorphisms were in linkage disequilibrium. The frequencies of the derived alleles at ADH1B ^* G (+MslI) allele, CYP2E1 ^* C2 (+PstI) allele and CYP2E1 ^* C (-DraI) allele were 8.48 ± 1.86, 1.20 ± 0.69, and 10.00 ± 1.90%, respectively. The ADH7 gene polymorphism showed a high level of heterozygosity; the frequency of the ADH7 ^* C (-StyI) allele was 44.58 ± 3.21%. A significantly higher frequency of CYP2E1 PstI C2 allele has been revealed in the CA group (P = 0.043; OR = 4.23; 95% CI 1.03–20.01). The tendency to significant effect of A1A2 genotype in ADH1B MslI polymorphism was observed for systolic blood pressure in the control group (P = 0.068). The statistically significant two-way interaction effects of ADH7 StyI and CYP2E1 DraI on diastolic blood pressure (P = 0.029) and on the serum high density lipoprotein level (P = 0.042) were also revealed. Association of A1A2 genotype in ADH1B MslI polymorphism with reduced amount in a serum of a very low density lipoprotein level (P = 0.045) have also been shown. This may result from multifunctional activity of alcohol metabolizing enzymes and their involvement in many metabolic and free radical reactions in the body.     

Intrapopulation Polymorphism of the Pine Marten (<Emphasis Type="Italic">Martes martes</Emphasis>, Carnivora,Mustelidae) from Tver Oblast

The intrapopulation polymorphism of the pine marten (Martes martes L. 1758) was assessed on the basis of studying five samplings of skulls, three of which were collected on the same territory at different times. The geographical distance between the three sampling areas varied from 60 to 240 km. Study of the material using the phenetic (250 skulls), morphometric (151 skulls), and molecular genetic (21 skin samples) approaches allowed us to characterize the pine marten as a species with a low level of polymorphism. The genetic diversity (π = 0.0069 ± 0.0041 and H = 0.90 ± 0.039) is determined by ancient demographic processes that took place in the Pleistocene and Holocene and are related to the ice-age history of this species, its expansion, and the formation of the population on the territory under study. Low levels of phenetic (μ = 1.48 ± 0.056, h = 0.14 ± 0.033) and morphological (CV = 3.37 ± 0.41) diversity as well as a low level of sexual dimorphism (Isd = 9.4) indicate that the pine marten occupies a specific and relatively narrow ecological niche and is involved in weak competition with smaller mustelid species.     

Bioactive effect of the preparation biostyl on the reproductive function of different genotypes of American mink

The different role of coat color mutations in the American mink on the per os effect of the biologically active preparation Biostyl was shown. The number of kits per female was the same in all control genotypes, including Standard (+/+ +/+), sapphire (a/a p/p), and lavender (a/a m/m): 4.4 ± 0.4, 4.4 ± 0.5, and 4.3 ± 0.5, respectively. Experimental groups of these genotypes have shown a great contrast among each other: stimulation of the reproductive function was 5.2 ± 0.3 in Standard minks, while suppression of the reproductive function was 3.8 ± 0.6, and 2.3 ± 0.5 in the double recessive mutants sapphire and lavender, respectively. The differentiation in body mass between experimental and control newborn Standard kits was not revealed. A significant decrease in the body mass of newborn experimental sapphire kits as compared to control group in a sex-specific manner was registered.     

Ecological preferences and seasonal dynamics of ticks (Acari: Ixodidae) on and off bovine hosts in the Eastern Cape Province,South Africa

A total of 31,425 ticks were collected from 10 cattle and also from six drag-samples during the 12-month study period. Adult ticks were removed from the right hand side of each animal and all instars of ticks were placed in containers filled with 70% ethanol. Based on morphological traits, 10 tick species were identified: Rhipicephalus (Boophilus) decoloratus (32.5%), R. evertsi evertsi (18.8%), R. appendiculatus (17.3%), Amblyomma hebraeum (16.3%), R. simus (7.7%), Ixodes pilosus (3.8%), Hyalomma rufipes (3.5%), R. follis (0.08%), Haemaphysalis elliptica (0.04%), H. silacea (0.02%). The southern African yellow dog tick, H. elliptica, was only found on vegetation. The agro-ecological zones differ significantly in tick species and their distribution. The A. hebraeum and R. evertsi evertsi counts were higher in Kowie Thicket (KT) during summer season (2.05 ± 0.01 and 1.00 ± 0.09, respectively) compared to Bedford Dry Grassland (BDG) and Bhisho Thornveld (BT) veld types. In all vegetation types, R. appendiculatus had higher counts in KT in spring (0.91 ± 0.08), summer (0.78 ± 0.08) and winter (0.78 ± 0.08). Rhipicephalus (Boophilus) decoloratus was more frequent in the BT (1.78 ± 0.11) during the summer season. BDG had lower tick infestation with R. evertsi evertsi being the most frequent species in summer. No H. rufipes was collected in the KT. Of epidemiological interest, R. (B.) microplus was absent in the study area which needs further investigation. Within the context of this study, we found agro-ecological differences and seasonal variations to have influence on tick species distribution.     

Modulation of alfa-adrenoceptor activity by beta-adrenoceptor agonists and antagonists in rat brain cortex membranes

The influence of β-adrenoceptor activation and inhibition by isoprenaline and propranolol on the specific binding of nonselective α₁- and α₂-adrenoceptor antagonists [³H]prazosin and [³H]RX821002 in rat cerebral cortex subcellular membrane fractions was studied. It was established that for the α₁- and α₂-adrenoceptors the ligand–receptor interaction corresponds to the model of one affinity pool of receptors and binding of two ligand molecules by one dimer receptor. The parameters of [³H]prazosin binding to α₁-adrenoceptors were: K _d = 1.85 ± 0.16 nM, B _max = 31.14 ± 0.35 fmol/mg protein, n = 2. The parameters of [³H]RX821002 binding to α₂-adrenoceptors were: K _d = 1.57 ± 0.27 nM, B _max = 7.2 ± 1.6 fmol/mg protein, n = 2. When β-adrenoceptors were activated by isoprenaline, the binding of radiolabelled ligands with α₁- and α₂-adrenoceptors occurred according to the same model. The affinity to [³H]prazosin and the concentration of active α₁-adrenoceptors increased by 27% (K _d = 1.36 ± 0.03 nM) and 84% (B _max = 57.37 ± 0.28 fmol/mg protein), respectively. The affinity of α₂-adrenoceptors to [³H]RX821002 decreased by 56% (K _d = 3.55 ± 0.02 nM), and the concentration of active receptors increased by 69% (B _max = 12.24 ± 0.06 fmol/mg protein). Propranolol alters the binding character of both ligands. For [³H]prazosin and [³H]RX821002, two pools of receptors were detected with the following parameters: K _d1 = 1.13 ± 0.09, K _d2 = 6.07 ± 1.06 nM, B _m1 = 11.36 ± 1.77, Bm2 = 51.09 ± 0.41 fmol/mg protein, n = 2 and K _d1 = 0.61 ± 0.02, K _d2 = 3.41 ± 0.13 nM, B _m1 = 1.88 ± 0.028, B _m2 = 9.27 ± 0.08 fmol/mg protein, n = 2, respectively. The concentration of active receptors (B _max) increased twofold for both ligands. It was suggested that α₁- and α₂-adrenoceptors in rat cerebral cortex subcellular membrane fractions exist as dimers. A modulating influence of isoprenaline and propranolol on the specific binding of the antagonists to α₁- and α₂- adrenoceptors was revealed, which was manifested in the activating effect on the [³H]prazosin binding parameters, in the inhibitory effect on the [³H]RX821002 binding parameters, and in a change of the general character of binding for both ligands.