环境因子对褐飞虱两种生物型种群参数影响的比较

比较了孟加拉型和生物型Ⅱ褐飞虱种群对高温、饥饿、浸水和杀虫剂等因子的反应。结果表明,35.0℃下孟加拉型若虫的致死中量时间(LT50)显著高于生物型Ⅱ,但两个生物型在26℃和37.5℃下的LT50间差异均不显著,而40.0℃时生物型Ⅱ若虫的LT50显著高于孟加拉型。在26、35.0℃和室内自然变温(26~35.0℃)条件下测定成虫耐饥力,两生物型间LT50均差异不显著。在各饥饿处理时间下,两生物型褐飞虱单雌平均产卵量差异均不显著。褐飞虱卵浸水1、3d和5d,两个生物型孵化率无显著差异,但生物型Ⅱ卵浸水5d后孵化率与对照相比差异显著,说明浸水5d对褐飞虱生物型Ⅱ卵的孵化率有影响。取食经浸水5d处理的稻株168h后,生物型Ⅱ若虫的死亡率与对照有显著差异,而孟加拉型死亡率与对照相比差异不显著;不浸水对照处理两个生物型的2~3龄若虫168h时就已全部发育为成虫,而浸水处理则到216h时才全部发育为成虫,这表明水稻浸水处理延迟了两个生物型若虫的发育进度。对于甲胺磷,药后1d、2d孟加拉型的致死中浓度(LC50)均显著小于生物型Ⅱ;对于噻嗪酮,孟加拉型药后5d的LC50均显著小于生物型Ⅱ,表明孟加拉型对这两种杀虫剂较生物型Ⅱ敏感。     

The complex influence of environmental factors on the state of microcirculation

The state of microcirculation system and its regulation in peace and after growing physical activity is analyzed on people living in different ecological regions. There are three main types of microcirculation. The level of regulation mechanisms activity depends on the type of microcirculation, region of residence and the value of physical activity. People living in a relatively clean regions have stable mechanisms of regulation despite of the level of activity. Mesoemic type living in toxic radiation regions have reduced contribution of VLF and LF-fluctuation (p < 0.05); hypoemic type living in toxic regions have VLF and LF-fluctuation (p < 0.05); hyperemic type living in toxic regions have LF-fluctuation (p < 0.05). We can conclude the tension of regulatory machanisms in microcirculation system increases under ecological pressure and borders on failure of adaptation process.     

影响黏红酵母黏附牙鲆肠黏液的因素研究

目的研究pH、温度、二价阳离子对黏红酵母黏附作用的影响以及不同生长阶段的黏红酵母对牙鲆肠黏液的黏附特点。方法以牙鲆肠黏液作为黏附模型,采用MTT比色法测定黏红酵母在上述影响因素作用下的黏附能力。结果在10~30℃黏红酵母对牙鲆肠黏液的黏附随温度升高而增强,中性偏酸的环境有利于黏红酵母的黏附;Ca2 能显著增加黏红酵母的黏附,但Mg2 促黏附作用不明显;处于对数生长期的黏红酵母对牙鲆肠黏液的黏附能力最强,其次是延滞期的酵母,而稳定期和衰亡期的黏红酵母黏附能力显著减弱。结论黏红酵母对牙鲆肠黏液的黏附作用不仅受多种环境因子的影响,也受其自身生理状态的影响,其黏附作用具有可控性,这对黏红酵母在牙鲆肠道内黏附、定植的调控有一定的参考价值。     

环境因素对安徽虫瘟霉生长发育的影响

安徽虫瘟霉是目前仅发现于我国的重要蚜虫病原真菌,对桃蚜具有明显的自然控制作用。本研究了温度和紫外光对安徽虫瘟等固体培养性状及不同温湿度组合对安徽虫瘟霉分生孢子萌发的影响。     

The influence of biological and environmental factors on metallothionein concentration in the blood

The concentration of metallothionein (MT), a low-molecular-weight protein, is regulated by many factors, primarily metals (zinc, cadmium, copper), cytokines, glucocorticoides and free radicals. These factors are determined by such aspects of human biology as gender, pregnancy and age, as well as by environmental factors including the use of oral contraceptives and cigarette smoking, all which may affect MT levels in the body.The aim of this study was to investigate the influence of these biological and environmental factors on MT concentrations in erythrocyte lysate and in plasma.MT concentrations were determined by a two-step direct enzyme-linked immunosorbent assay. Evaluation of exposure to cigarette smoking was performed by checking cotinine levels in the plasma of subjects.The studies showed higher MT concentrations in both the erythrocyte lysate and plasma of women when compared to men. Furthermore, pregnancy causes an increase of MT concentration in plasma, while oral contraceptives cause an elevated concentration of MT in erythrocyte lysate. Age impacts plasma MT concentrations in men, whereas it does not affect concentrations of MT in erythrocyte lysate.     

Integrated influence of environmental factors on the state of microcirculation

The microcirculation system and its regulation at rest and after gradually growing physical activity in subjects living in different environmental regions was studied using laser Doppler flowmetry. Three main types of microcirculation were found. The activity of regulation mechanisms depended on the microcirculation type, residence region, and level of physical activity. Subjects living in relatively clean regions displayed stable regulation mechanisms irrespective of the level of activity. Subjects with the mesoemic type of microcirculation from regions with a high toxic contamination, high radiation background, or exposed to combined adverse factors, as well as subjects with the hypoemic type exposed to toxic and combined factors displayed a decreased contribution of VLF and LF oscillations (p < 0.05), and subjects with the hyperemic type from toxically contaminated regions displayed a decreased contribution of LF oscillations (p < 0.05). The results indicate that, under environmental pressure, regulatory mechanisms are exerted to the extent verging on adaptation failure.     

The influence of environmental factors on nitrate reductase activity in freshwater phytoplankton

Water samples were taken from three regions in the Kinneret ecosystem (the Watershed (WS), the National Water Carrier (NWC) and the lake) over a 14 month period and nitrate reductase (NR) activity measured by a simplified assay previously developed for field studies. A complex relationship between NR activity and ambient NO₃ and/or NH₄ concentrations was observed. NR activity was not generally predictable from ambient nutrient concentrations. No correlation between NR activity and the ambient orthophosphate (SRP) concentrations or the dissolved, inorganic N : P atomic ratio was observed, although NR activity appeared to correlate with both NO₃ or NH₄ uptake. Our results suggest that NR activity is related to the N nutritional status of the cells and their nutrient prehistory rather than ambient nutrient concentrations.     

The influence of some environmental factors on the production of Carex vesicaria and Phalaris arundinacea

The study deals with the annual cycles of biomass, productivity and necrosis of the perennial wetland species Carex vesicaria and Phalaris arundinacea, and with the main growth parameters during the first part of 1979. The amplitudes of biomass variation differ, but other features of the development are largely the same. To detect the various climatic factors which determine the above-ground biomass dynamics, a procedure of multiple stepwise regression has been used. Regressions for annual trend and variation in production were obtained. They provide coarse models, which may be improved by including translocation to belowground organs.Nomenclature follows P. Fournier (1977): Les quatres flores de France. Paris.     

Influence of some environmental factors on nitrogen fixation in the rhizosphere of rice

Summary Nitrogen fixers make up a large percentage of the total microflora in the rhizosphere of lowland rice. There are more aerobic nitrogen fixers than there are anaerobic ones. When soil crumbs from the root zone were placed on a nitrogen free agar medium and inoculated at 0, 5, 10, and 21 percent oxygen concentration, colonies of aerobic nitrogen fixers reached their greatest diameter at 5 and 10 percent oxygen. In acetylene reduction assays rice plants grown in paddy fields and in solution culture were tested for the nitrogenase activities of their roots at different oxygen tensions. Nitrogenase activity was highest at 3 percent oxygen, lower at 0 percent, and far lower at 21 percent. When rice was grown in solution culture the redox potential of the nutrient solution strongly influenced nitrogenase activity. With declining redox potential, nitrogenase activity increased to a maximum value but dropped sharply as redox potential further decreased. Ten ppm of combined nitrogen as urea depressed nitrogenase activity on excised roots. Combined nitrogen applied to one part of the root system affected, to some extent, nitrogen fixation on other roots kept in a solution without nitrogen. Nitrogenase activity in a fertility trial with lowland rice, examined at several dates, showed no inhibitory effect of fertilizer nitrogen, however, presumably because the nitrogen concentration in the soil solution rapidly decreased. Instead, an overall stimulating effect of nitrogen dressing was noticeable. Diurnal fluctuations of nitrogenase activity in the rhizosphere, with a peak in the afternoon and low fixation rates after low solar radiation, suggest a photosynthetic effect on nitrogen fixation. re]19751208     

The influence of some environmental factors on learning and aggregation in locust hoppers

• 1.1. Using the hoppers of two locust species, Locusta migratoria migratorioides (R. & F.) and Schistocerca gregaria Forsk., an attempt was made to study the importance of a patchy physical environment in bringing hoppers together long enough to become habituated to one another.
• 2.2. When offered tethered decoy hoppers in an evenly heated and lighted area, gregarious hoppers spent more time resting near the decoys than solitary hoppers. The test animals reacted in a number of ways when touched by or when touching decoys, and the proportions of the different types of reactions were different in solitary and gregarious hoppers.
• 3.3. When tethered decoy locusts were placed on a warmed spot of the arena floor the behaviour of solitary and gregarious hoppers was almost the same. The time spent grouped near the decoys was increased for both types of test hopper, but far more for solitary than gregarious hoppers. Under these conditions the proportions of the various types of reaction given by the solitary test hoppers was nearly the same as those for the gregarious hoppers.
• 4.4. Solitary Schistocerca test hoppers, allowed to group on a warmed part of the arena floor before testing, showed behaviour typical of gregarious hoppers when placed in an evenly heated arena with decoys. Similarly trained Locusta hoppers showed intermediate behaviour, confirming that Locusta hoppers learn more slowly than those of Schistocerca.
• 5.5. The importance of the experiments to field conditions is discussed.
     

The algae-lytic ability of bacterium DC10 and the influence of environmental factors on the ability

Nowadays, eutrophication and massive accumula-tions of microalgae have caused serious environmental problems. So it is very important to find an effective method for controlling the growth of the algae and the algal blooms. Measures for controlling the algae in-clude physical, chemical and biological means. Physi-cal means are limited and usually act as an assistant for controlling the algae, and include mechanical means, high frequent electromagnetic pulses and ul-trasonic processes[1]. Algae…     

The influence of rice plant age on susceptibility to the rice water weevil,Lissorhoptrus oryzophilus

Plant age‐ and plant stage‐related changes in the resistance of rice, Oryza sativa, to its most important insect pest in the US, the rice water weevil (Lissorhoptrus oryzophilus), were investigated in a series of field and greenhouse choice and no‐choice studies. Rice plants were susceptible to infestation by rice water weevils over a broad range of plant ontogenetic stages, from at least the early vegetative stage to well into the reproductive stage. There was, however, a clear preference expressed by rice water weevils in both choice and no‐choice experiments for plants in (or nearly in) the tillering stage of development, with pre‐tillering and reproductive stage plants less preferred. The relationship between rice plant age and susceptibility to weevils is thus nonlinear. This study constitutes one of the most thorough studies to date of the relationship in a grass species between plant age and susceptibility to herbivores. The results provide a biological explanation for observed patterns of weevil infestations and a rationale for the cultural practice of delayed flooding.     

The influence of environmental factors upon induced compensatory hyperplasia in the rat liver

This study has examined the influence of a controlled environment upon the nature of the compensatory hyperplasia which occurs in the rat liver after two-thirds partial hepatectomy. Rats were adapted to a reversed lighting schedule (lights off 09.30 to 21.30 h), and food was only available during the first 8 h of the dark period. Partial hepatectomies were performed at either 10.00, 16.00 or 20.00 h, and the response over the first 36 h monitored by 2-hourly measurements of the flash tritiated thymidine labelling index and the mitotic index. DNA synthesis was initiated within 16-18 h of operation, irrespective of when hepatectomies were performed, though the ensuing patterns of DNA synthesis were rather different. On the other hand, the initiation of mitotic activity was very much dependent upon the time of day that resections were carried out. Hepatectomy at 20.00 h resulted in a rise in mitotic activity some 22-24 h later, but hepatectomy at 10.00 h caused a further 6 h delay in this rise. The onset of mitotic activity appeared to be related to recent feeding, and it is proposed that in the absence of recent nutrition, DNA-synthesizing hepatocytes may have an extended tS and/or tG2.     

The effect of growth media and physical treatments on the adhesion properties of canine probiotics

Aims

The manufacturing processes have been reported to influence the properties of probiotics with potential impact on health properties. The aim was to investigate the effect of different growth media and inactivation methods on the properties of canine‐originated probiotic bacteria alone and in combination mixture.

Methods and Results

Three established dog probiotics, Lactobacillus fermentum VET9A, Lactobacillus plantarum VET14A and Lactobacillus rhamnosus VET16A, and their combination mixture were evaluated for their adhesion to dog mucus. The effect of different growth media, one reflecting laboratory and the other manufacturing conditions, and inactivation methods (95°C, 80°C and UV irradiation) on the mucus adhesion of the probiotic strains was characterized. Evaluation of dog probiotics was supported by cell visualization using transmission electron microscopy (TEM). Higher adhesion percentage was reported for probiotic strains growing in laboratory rather than in manufacturing conditions (P < 0·05). Inactivation by heat (95°C, 80°C) decreased the adhesion properties when strains were cultivated in soy‐based growth media compared with those grown in MRS broth (P < 0·05). TEM observations uncovered differences in cell‐surface components in nonviable forms of probiotic strains as compared with their viable forms.

Conclusions

Manufacturing process conditions such as growth media and pretreatment methods may significantly affect the adhesive ability of the tested strains.

Significance and Impact of the Study

Growth conditions, growth media, pretreatment methods and different probiotic combinations should be carefully considered for quality control of existing probiotics and for identification of new probiotics for dogs. These may also have an impact on health benefits for the host.     

A method to associate all possible combinations of genetic and environmental factors using GxE landscape plot

AbbreviationsGxE - Gene-environment interactions, GWAS - Genome-wide association study, MAFs - Minor allele frequencies, SNPs - Single nucleotide polymorphisms, EWAS - Environment-wide association study, FDR - False discovery rate, JPT+CHB - HapMap population of Japanese in Tokyo, Japan - Han Chinese in Beijing.