Recent effective population size in Eastern European plain Russians correlates with the key historical events.

Effective population size reflects the history of population growth, contraction, and structuring. When the effect of structuring is negligible, the inferred trajectory of the effective population size can be informative about the key events in the history of a population. We used the IBDNe and DoRIS approaches, which exploit the data on IBD sharing between genomes, to reconstruct the recent effective population size in two population datasets of Russians from Eastern European plain: (1) ethnic Russians sampled from the westernmost part of Russia; (2) ethnic Russians, Bashkirs, and Tatars sampled from the Volga-Ural region. In this way, we examined changes in effective population size among ethnic Russians that reside in their historical area at the West of the plain, and that expanded eastward to come into contact with the indigenous peoples at the East of the plain. We compared the inferred demographic trajectories of each ethnic group to written historical data related to demographic events such as migration, war, colonization, famine, establishment, and collapse of empires. According to IBDNe estimations, 200 generations (~6000 years) ago, the effective size of the ancestral populations of Russians, Bashkirs, and Tatars hovered around 3,000, 30,000, and 8,000 respectively. Then, the ethnic Russians exponentially grew with increasing rates for the last 115 generations and become the largest ethnic group of the plain. Russians do not show any drop in effective population size after the key historical conflicts, including the Mongol invasion. The only exception is a moderate drop in the 17th century, which is well known in Russian history as The Smuta. Our analyses suggest a more eventful recent population history for the two small ethnic groups that came into contact with ethnic Russians in the Volga-Ural region. We found that the effective population size of Bashkirs and Tatars started to decrease during the time of the Mongol invasion. Interestingly, there is an even stronger drop in the effective population size that coincides with the expansion of Russians to the East. Thus, 15-20 generations ago, i.e. in the 16-18th centuries in the trajectories of Bashkirs and Tatars, we observe the bottlenecks of four and twenty thousand, respectively. Our results on the recent effective population size correlate with the key events in the history of populations of the Eastern European plain and have importance for designing biomedical studies in the region.

Relationship between total phenolic contents and biological properties of propolis from 20 different regions in South Korea.

BACKGROUND: Propolis (or bee glue), collected from botanical sources by honey bee, has been used as a popular natural remedies in folk medicine throughout the world. This study was conducted to assess growth inhibitory effects of ethanol extracts of propolis (EEPs) from 20 different regions in South Korea on human intestinal bacteria as well as their human ß-amyloid precursor cleavage enzyme (BACE-1), acetylcholinesterase (AChE) inhibitory, antioxidant, antiproliferative, and anti-human rhinovirus activities. METHODS: The Bonferroni multiple-comparison method was used to test for significant differences in total polyphenol and flavonoid contents among EEP samples using SAS 9.13 program. Correlation coefficient (r) analysis of the biological activities of EEP samples was determined using their 50 % inhibition concentration or minimal inhibitory concentration values and their polyphenol or flavonoid contents in 20 native Korean EEP samples. RESULTS: The amounts of total polyphenol and flavonoids in the Korean EEP samples ranged from 49 to 239 mg gallic acid equivalent (GAE)/g EEP (Brazilian, Chinese, and Australian samples, 127-142 mg GAE/g EEP) and from 21 to 50 mg quercetin equivalent (QE)/g EEP (Brazilian, Chinese, and Australian samples, 33-53 mg QE/g EEP), respectively. Correlation coefficient analysis showed that total polyphenol contents may be negatively correlated with 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity (r = -0.872) and total flavonoid content has no correlation with the activity (r = 0.071). No direct correlation between BACE-1 inhibition, AChE inhibition, or antiproliferative activity and total polyphenol or total flavonoid content in Korean EEP samples was found. Gram-positive and Gram-negative bacteria were observed to have different degrees of antimicrobial susceptibility to the EEP samples examined, although ciprofloxacin susceptibility among the bacterial groups did not differ greatly. CONCLUSIONS: Further studies will warrant possible applications of propolis as potential therapeutic BACE-1 blocker, antioxidant, antiproliferative agent, and antimicrobial agent.

Effects of curcuminoids identified in rhizomes of Curcuma longa on BACE-1 inhibitory and behavioral activity and lifespan of Alzheimer's disease Drosophila models.

BACKGROUND: Alzheimer's disease (AD) is the most common type of presenile and senile dementia. The human ß-amyloid precursor cleavage enzyme (BACE-1) is a key enzyme responsible for amyloid plaque production, which implicates the progress and symptoms of AD. Here we assessed the anti-BACE-1 and behavioral activities of curcuminoids from rhizomes of Curcuma longa (Zingiberaceae), diarylalkyls curcumin (CCN), demethoxycurcumin (DMCCN), and bisdemethoxycurcumin (BDMCCN) against AD Drosophila melanogaster models. METHODS: Neuro-protective ability of the curcuminoids was assessed using Drosophila melanogaster model system overexpressing BACE-1 and its substrate APP in compound eyes and entire neurons. Feeding and climbing activity, lifespan, and morphostructural changes in fly eyes also were evaluated. RESULTS: BDMCCN has the strongest inhibitory activity toward BACE-1 with 17 µM IC50, which was 20 and 13 times lower than those of CCN and DMCCN respectively. Overexpression of APP/BACE-1 resulted in the progressive and measurable defects in morphology of eyes and locomotion. Remarkably, supplementing diet with either 1 mM BDMCCN or 1 mM CCN rescued APP/BACE1-expressing flies and kept them from developing both morphological and behavioral defects. Our results suggest that structural characteristics, such as degrees of saturation, types of carbon skeleton and functional group, and hydrophobicity appear to play a role in determining inhibitory potency of curcuminoids on BACE-1. CONCLUSION: Further studies will warrant possible applications of curcuminoids as therapeutic BACE-1 blockers.

Behavioural and electroantennogram responses of the stable fly (Stomoxys calcitrans L.) to plant essential oils and their mixtures with attractants.

BACKGROUND: Insect olfactory organs possess many olfactory receptor neurons, which detect many different sets of odorants in nature. In order to feed on blood meals, stable flies locate host animals and humans using chemical cues such as 1-octen-3-ol and butyric acid. In the present study, behavioural and electroantennogram (EAG) response patterns to repellent volatiles from essential oils (EOs) of Zanthoxylum piperitum and Z. armatum in combination with the attractants were investigated. RESULTS: Components of the EOs such as cuminaldehyde, citronellal, neral, linalool, linalool oxide, terpinen-4-ol, 1,8-cineole, and piperitone induced remarkable repellent behaviours in the stable fly. EAG responses in the fly antenna to these chemicals showed a dose-dependent manner. The patterns of behavioural and EAG responses were significantly altered depending on the ratios of 1-octen-3-ol or butyric acid to the EOs or compounds in the air mixtures. CONCLUSION: The present study demonstrated that the Zanthoxylum EOs decreased the levels of response of flight behaviours of the stable fly towards host volatile compounds. The combinations of odorant mixtures of the attractants with the EOs and their components affect the representation of behavioural and EAG responses of the flies. The summation and integration patterns of olfactory responses measured by the EAG indicated that the peripheral olfactory networks in antennae could process the odorant complexity of different odorant mixtures between attractants and repellents.

Toxicity and synergic repellency of plant essential oil mixtures with vanillin against Aedes aegypti (Diptera: Culicidae).

In all triplicate tests of six plant essential oils and of vanillin mixtures, we corroborated strong insecticidal and repellent activities against adult Aedes aegypti (L.). Essential oils with potent toxic fumigant activities also exhibited repellency. Compared with N, N-diethyl-3-methylbenzamide, 5% of the essential oil concentrations of cassia, lemongrass, lemon eucalyptus, and xanthoxylum oils did not show repellent effects. However, a composition oflemongrass oil, xanthoxylum oil, and vanillin (1:3:1, vol:vol:wt) provided 270 min of complete protection time (CPT) compared with 247.5 min CPT with 15% N, N-diethyl-3-methylbenzamide. The CPT depended on concentration, presence ofvanillin, or on both factors. When we applied a mixture of lemongrass oil: xanthoxylum oil: vanillin (1:1:1, vol:vol:wt) to the Viscopearl formulation, or porous cellulose beads, it provided gradual release of volatile compounds, thus showing >90% of repellency for 2 h. The behavioral and electrophysiological approaches we drew upon in our current study demonstrated that plant essential oil mixtures combined with vanillin showed strong and durable repellency to the mosquito. We claim that such combinations of plant essential oils and vanillin found in current study propose a viable commercial product suitable for future application in protecting a person from mosquito bites.

Enhanced toxicity of binary mixtures of larvicidal constituents from Asarum heterotropoides root to Culex pipiens pallens (Diptera: Culicidae).

The toxicity of pellitorine alone or in combination with (-)-asarinin, alpha-asarone, methyleugenol, or pentadecane (1:1, 1:2, 1:3, 2:1, and 3:1 ratios) to third instars from an insecticide-susceptible KS-CP strain and -resistant DJ-CP colony of Culex pipiens pallens Coquillett was evaluated using a direct-contact mortality bioassay. The binary mixture of pellitorine and (-)-asarinin (3:1 ratio) was significantly more toxic against KS-CP larvae (0.95 mg/liter) and DJ-CP larvae (1.07 mg/liter) than either pellitorine (2.08 mg/liter for KS-CP and 2.33 mg/liter for DJ-CP) or (-)-asarinin (11.45 and 12.61 mg/liter) alone. The toxicity of the other binary mixtures (1:1, 1:2, 1:3, and 2:1 ratios) and pellitorine did not differ significantly from each other. Based on the co-toxicity coefficient (CC) and synergistic factor (SF), the three binary mixtures (1:3, 2:1, and 3:1) operated synergistically (CC, 250-390 and SF, 1.4-2.2 for KS-CP; CC, 257-279 and SF, 1.1-2.1 for DJ-CP). The binary mixtures of pellitorine and (-)-asarinin merit further study as potential larvicides for the control of insecticide-resistant mosquito populations.

Enhanced repellency of binary mixtures of Zanthoxylum armatum seed oil, vanillin, and their aerosols to mosquitoes under laboratory and field conditions.

The repellency of Zanthoxylum armatum seed oil (ZA-SO), alone or in combination with vanillin (VA), its six major constituents, and another four major previously known Zanthoxylum piperitum fruit oil constituents, as well as aerosol products containing 5 or 10% ZA-SO and 5% VA, was evaluated against female Aedes aegypti in laboratory and field studies. Results were then compared with those of N,N-diethyl-3-methylbenzamide (DEET) as a standard. Hand in cage laboratory tests showed that 0.2, 0.1, and 0.05 mg/cm2 ZA-SO resulted in > 92% protection through 30-min postexposure and was not significantly different than 0.05 mg/cm2 DEET. Skin treated with linalool and limonene (from Z. armatum) provided > 80% repellency to female Ae. aegypti at 10-min exposure, whereas cuminaldehyde, citronellal, geranyl acetate, and cuminyl alcohol (from Zanthoxylum piperitum) provided > 90% protection during this same time period. Only cuminaldehyde and citronellal provided complete protection comparable to DEET at 10-min postexposure. After that time, repellency of all plant constituents to mosquitoes was considerably decreased (< approximately 65%). An increase in repellency and duration of effectiveness was produced by a binary 1:4 mixture of ZA-SO and VA (0.05:0.2 mg/cm2) that was significantly more effective than 0.05 mg/cm2 DEET through 90 min. In field tests, an aerosol formulation containing 5 or 10% ZA-SO plus 5% VA gave 100% repellency at 60-min postexposure. Although these formulations were equal to the level of protection afforded by 10% DEET, repellency to the binary ZA-SO aerosol formulations at 90 min was significantly less effective than DEET. However, mixtures formulated from ZA-SO and VA merit further study as potential repellents for protection of humans and domestic animals from biting and nuisance caused by mosquitoes.

Enhanced repellency of binary mixtures of Zanthoxylum piperitum pericarp steam distillate or Zanthoxylum armatum seed oil constituents and Calophyllum inophyllum nut oil and their aerosols to Stomoxys calcitrans.

BACKGROUND: The repellency to stable fly, Stomoxys calcitrans (L.), of Zanthoxylum piperitum (L.) DC pericarp steam distillate (ZP-SD), Zanthoxylum armatum DC seed oil (ZA-SO) and their constituents alone or in combination with Calophyllum inophyllum L. nut oil (CI-NO), as well as six aerosol formulations containing ZP-SD or ZP-SO and CI-NO, was compared with that of a synthetic repellent, DEET, using an exposed human hand bioassay. RESULTS: At 0.20 mg cm(-2), ZP-SD treatments resulted in 91 and 68% repellency following 30 and 60 min exposure respectively, while DEET gave 100 and 84% repellency. ZA-SO was less effective than ZP-SD. At 0.2 mg cm(-2), the most active constituents, cuminaldehyde, cuminyl alcohol, limonene and methyl cinnamate, gave 82, 74, 74 and 64% repellency at 30 min respectively, but DEET gave 100 and 87% repellency at 30 and 60 min. An increase in effectiveness and duration of repellency was produced by binary mixtures of ZP-SD, ZA-SO or bioactive constituents (each 0.01 mg cm(-2)) and CI-NO (0.99 mg cm(-2)). The repellency of aerosols containing 2.5% ZP-SD or 2.5% ZA-SO and 2.5% CI-NO was comparable with that of 5% DEET aerosol. CONCLUSION: Mixtures formulated from ZP-SD, ZA-SO or bioactive constituents and CI-NO could be useful as potential repellents for the control of stable fly populations in light of global efforts to reduce the level of highly toxic synthetic repellents.