The effect of pressure on the growth of tumour cell colonies

This paper describes some experiments on the manner in which external pressure affects cell colony growth in general, and tumour growth in particular. More precisely, our results show that cell colony borders growing under high-pressure conditions have geometrical and dynamical properties that are markedly different from those corresponding to growth under homeostatic, normal pressure conditions. These behaviours are characterized by means of the so-called dynamical exponents of each type of growth. These are shown to correspond to statistical properties of solutions of some stochastic partial differential equations that account for the evolution of the interface between the expanding colony and the surrounding medium.     

Heterogeneity of the populations of marine luminescent bacteria Photobacterium leiognathi under different conditions of cultivation

Manifestation of pleiotropic effects in the isogenic variants of the luminescent bacterium Photobacterium leiognathi 54 was investigated. The decrease or increase of the expression level of bioluminescence was caused by changes in lux operon regulation. The dynamics of the bioluminescence of dark and dim variants did not differ from the dynamics of the initial luminescent variant, but dependence of the level of luminescence intensity on the exogenous autoinducer of the lux operon was revealed. The investigated variants of P. leiognathi 54 inherited fairly stable morphological characteristics, colony architectonics, level of luminescence, and activity of some enzymes; variants with reduced bioluminescence formed colonies of the S type. Stable bright variants with S-and R-type colonies appeared both in the initial strain population and in the dark variant population, but with smaller frequency. Populations of the bright variant with R-type colonies were most heterogeneous; this can be determined by the lack of glucose repression of the bioluminescence in contrast to other investigated inherited variants of P. leiognathi.     

圆唇散白蚁补充生殖蚁的类型与建群能力

摘要: 【目的】为了探讨圆唇散白蚁Reticulitermes labralis补充生殖蚁对巢群稳定和发展的作用。【方法】对野外巢群进行调查研究, 及对婚飞成虫通过雌雄配对与补充生殖蚁隔离巢群进行人工饲养的对比研究。【结果】在野外巢群只发现1对原始蚁王蚁后, 而补充生殖蚁的数量最多可达到689头/巢。圆唇散白蚁有3种类型的补充生殖蚁, 即由工蚁转化来的无翅型补充生殖蚁、若蚁转化来的翅芽型补充生殖蚁和末龄若蚁羽化来的拟成虫型补充生殖蚁。实验室条件下婚飞配对群体和隔离群体建群1个月后的存活率分别为64%和96%。建巢初期婚飞配对群体的子代数目增长缓慢, 2个月时的群体数量为6.3±1.54, 10个月时的群体数量也仅为8.4±1.47; 而隔离建群补充生殖蚁2个月时的群体数量为52.4±6.44, 10个月时的群体数量为164.3±20.85, 都高于婚飞配对群体。 此外, 野外巢群的补充蚁后跟原始蚁后一样都具有发达的卵巢。【结论】在圆唇散白蚁中补充生殖蚁是白蚁巢群主要的繁殖力量, 也是建立新巢群的重要繁殖品级。     

Trichogramma parasitoids for control of Lepidopteran borers in Taiwan: species,life‐history traits and Wolbachia infections

Trichogramma, polyphagous endoparasitoids of lepidopteran eggs, are used against a variety of crop pests throughout the world including those of sugar cane and corn in south‐eastern Asia. Their ability to be easily and economically reared on factitious hosts and their wide host range have contributed to their widespread use in pest control. The overall aim of this study was to select strains for eventual release in crop areas for control of lepidopteran borer pests of sugar cane and corn. To this end, we identified common Trichogramma species emerging from corn borer egg masses throughout south‐western Taiwan, compared their life‐history characteristics, assessed their thermal limits and identified the Wolbachia infection status of collected Trichogramma parasitoids. Trichogramma ostriniae was the most commonly collected species on corn, with occasional detection of T. chilonis and an unidentified species designated as T. sp. y. Although the sex ratio varied widely between sites, Wolbachia infection was detected only at a single site in one species (T. ostriniae). Wolbachia‐infected T. ostriniae were tolerant to high temperature stress. Trichogramma chilonis had lowest fecundity of the three species tested, and a Wolbachia‐infected T. ostriniae strain had lower fecundity than an uninfected strain. Given the limited availability of distribution and historical data for Trichogramma species in Taiwan, the current study provides a baseline for future work and also highlights the importance of accurately identifying species when establishing colonies of natural enemies for biocontrol.     

Changes of species specific cuticular hydrocarbon profiles in the cockroaches Nauphoeta cinerea and Leucophaea maderae reared in heterospecific groups

The cuticular hydrocarbon profiles of the cockroaches Nauphoeta cinerea and Leucophaea maderae are species-specific when maintained in homospecific rearings. When individuals were reared in mixed species colonies, they initially remained in homospecific groups under different shelters. However, after 14 days they formed one heterospecific group with cuticular profiles showing characteristics of both species. When individuals were returned in monospecific rearings, their cuticular hydrocarbon profiles returned to species-specific ones within 3 weeks.     

Seasonal dynamics and the structure of colonies of Proterospongia skujae Bourrelly

The seasonal dynamics, the structure of colonies and the abundance of cells in the colonies of the monad Proterospongia skujae have been simultaneously studied in the river Danube and in a backwater of the Danube. Significant differences have been found in both the dynamics and the abundance of P. skujae in selected localities. Colonies are formed of 2 up to 16 cells, most frequency of 4 and 8 cells.     

实验兔三个封闭群微卫星DNA多态性遗传分析

目的 对日本大耳白兔、青紫蓝兔、新西兰兔三个封闭群体开展群体遗传学分析.方法 利用10个微卫星位点,进行Hardy-Weinberg平衡(HWE)检验,统计三个种群的基因频率、观测杂合度、期望杂合度、F值和遗传距离.结果 青紫蓝品种在12L1E11位点,新西兰品种在INRACCDDV0087位点与INRACCDDV0203位点,日本大耳白兔在Sat12位点与INRACCDDV0203,P＜0.05,显著偏离HWE,多数表现为杂合子缺陷;三个群体在Sat13、So144、6L1F10、7L1F1、12L4A1、INRACCDDV0016点上均符合HWE;各位点平均等位基因数5.9,种群整体基因频率差别较大,其范围为0 -0.9060;三个种群的平均观测杂合度为0.6204,平均期望杂合度为0.6178;群体间分化系数(Fst)平均为0.0750,日本大耳白兔和青紫蓝兔遗传距离最近为0.1223,青紫蓝兔与新西兰兔遗传距离最远为0.1934.结论 三个种群的遗传结构均表现出遗传稳定性和均一性,在10个微卫星位点上呈现高度多态性,种群间遗传分化明显.     

Use of nanocolonies to detect minimal residual disease in patients with leukemia t(8;12)

Molecular Biology - A complete diagnostic procedure was developed to detect single molecules of the AML1-ETO mRNA in whole blood and bone marrow samples of leukemia t(8;21)(q22;q22) patients. The...     

Possible involvement of NO in the stimulating effect of pifithrins on survival of hemopoietic clonogenic cells

Pifithrin α (PFTα), one of the first known low molecular weight modulators of activity of tumor suppressor p53, increases survival of hemopoietic clonogenic cells (evaluated by the criterion of formation of endogenous spleen CFU-C8 colonies in irradiated animals). This effect appeared when PFTα was administered either before or after irradiation. Increase in CFU-C8 was also observed after administration of two PFTα analogs, derivatives of 2-amino-4,5,6,7-tetrahy-drobenzothiazole. These included a parent compound, 2-ATBT (2-amino-4,5,6,7-tetrahydrobenzothiazole), which is used for synthesis of PFTα, and a product of its intramolecular cyclization under physiological conditions, cyclo-PFT (2-(4-methylphenyl)imidazo[2,1-b]-5,6,7,8-tetrahydrobenzothiazole). Earlier we found that many low molecular weight compounds increasing number of CFU-C8 (e.g. isothiourea derivatives) demonstrate NO inhibitory activity. Such activity was also found in 2-ATBT and cyclo-PFT by means of EPR spectroscopy of NO. These compounds caused more than twofold inhibition of NO production in vivo. Thus, it has been demonstrated that PFTα and its structural analogs increase survival of hemopoietic clonogenic cells in vivo, and NO may play a role in the mechanism of this effect.     

Histological survey of symbionts and other conditions in razor clam Ensis arcuatus (Jeffreys, 1865) (Pharidae) of the coast of Galicia (NW Spain)

Symbionts and abnormal conditions of razor clam Ensis arcuatus were surveyed in three commercially important natural beds of Galician estuaries (NW Spain). Samples of 15-20 E. arcuatus were collected every 2 months from January 2003 until July 2004 and processed for histological examination. Prokaryote-like colonies, renal coccidians, gregarines, Trichodina sp. ciliates, haplosporidian-like plasmodia, turbelaria, trematode metacercariae, cestode-like larvae and basophilic inclusion bodies were observed in razor clam tissues without causing host damage. Bucephalid digenean sporocysts and germinoma were seen in some samples causing moderate or severe damage to the host depending on the intensity of infection and both could be a cause for concern if prevalence reached epizootic levels in Galician E. arcuatus populations. None of the parasites detected is OIE notifiable and, in general, the commercially exploited beds studied seem to be devoid of serious pathogens.