Characterization of Vibrio fluvialis-Like Strains Implicated in Limp Lobster Disease

Studies were undertaken to characterize and determine the pathogenic mechanisms involved in a newly described systemic disease in Homarus americanus (American lobster) caused by a Vibrio fluvialis-like microorganism. Nineteen isolates were obtained from eight of nine lobsters sampled. Biochemically, the isolates resembled V. fluvialis, and the isolates grew optimally at 20°C; none could grow at temperatures above 23°C. The type strain (1AMA) displayed a thermal reduction time (D value) of 5.77 min at 37°C. All of the isolates required at least 1% NaCl for growth. Collectively, the data suggest that these isolates may embody a new biotype. Pulsed-field gel electrophoresis (PFGE) analysis of the isolates revealed five closely related subgroups. Some isolates produced a sheep hemagglutinin that was neither an outer membrane protein nor a metalloprotease. Several isolates possessed capsules. The isolates were highly susceptible to a variety of antibiotics tested. However, six isolates were resistant to erythromycin. Seventeen isolates harbored plasmids. Lobster challenge studies revealed that the 50% lethal dose of a plasmid-positive strain was 100-fold lower than that of a plasmid-negative strain, suggesting that the plasmid may enhance the pathogenicity of these microorganisms in lobsters. Microorganisms that were recovered from experimentally infected lobsters exhibited biochemical and PFGE profiles that were indistinguishable from those of the challenge strain. Tissue affinity studies demonstrated that the challenge microorganisms accumulated in heart and midgut tissues as well as in the hemolymph. Culture supernatants and polymyxin B lysates of the strains caused elongation of CHO cells in tissue culture, suggesting the presence of a hitherto unknown enterotoxin. Both plasmid-positive and plasmid-negative strains caused significant dose-related intestinal fluid accumulations in suckling mice. Absence of viable organisms in the intestinal contents of mice suggests that these microorganisms cause diarrhea in mice by intoxication rather than by an infectious process. Further, these results support the thermal reduction data at 37°C and suggest that the mechanism(s) that led to fluid accumulation in mice differs from the disease process observed in lobsters by requiring neither the persistence of viable microorganisms nor the presence of plasmids. In summary, results of lobster studies satisfy Koch's postulates at the organismal and molecular levels; the findings support the hypothesis that these V. fluvialis-like organisms were responsible for the originally described systemic disease, which is now called limp lobster disease.     

莱茵衣藻中Limp77基因干涉后油脂含量升高

随着能源危机问题日益严重,可再生能源的研究渐渐成为目前研究的热点.微藻生物能源又以众多的优点成为目前可再生能源的研究重点.我们发现,在减氮培养下的莱茵衣藻,其油脂含量增加,Limp77基因的表达量明显下降.Limp77基因编码的是一类CCCH型锌指蛋白,具有通过与DNA、RNA结合来实现转录的调控或通过调控其它基因转录的锌指蛋白来实现转录调控的功能,极可能参与到莱茵衣藻油脂代谢调控中.通过利用RNAi干涉技术构建Limp77基因的干涉载体,并通过玻璃珠法转入莱茵衣藻（Chlamydomonas reinhardtii）2A38中,研究其与油脂相关的生理生化指标的变化.实验结果表明,Limp 77基因明显抑制莱茵衣藻油脂的积累.     

The Childhood Leukemia International Consortium

Background: Acute leukemia is the most common cancer in children under 15 years of age; 80% are acute lymphoblastic leukemia (ALL) and 17% are acute myeloid leukemia (AML). Childhood leukemia shows further diversity based on cytogenetic and molecular characteristics, which may relate to distinct etiologies. Case–control studies conducted worldwide, particularly of ALL, have collected a wealth of data on potential risk factors and in some studies, biospecimens. There is growing evidence for the role of infectious/immunologic factors, fetal growth, and several environmental factors in the etiology of childhood ALL. The risk of childhood leukemia, like other complex diseases, is likely to be influenced both by independent and interactive effects of genes and environmental exposures. While some studies have analyzed the role of genetic variants, few have been sufficiently powered to investigate gene–environment interactions. Objectives: The Childhood Leukemia International Consortium (CLIC) was established in 2007 to promote investigations of rarer exposures, gene–environment interactions and subtype-specific associations through the pooling of data from independent studies. Methods: By September 2012, CLIC included 22 studies (recruitment period: 1962–present) from 12 countries, totaling approximately 31 000 cases and 50 000 controls. Of these, 19 case–control studies have collected detailed epidemiologic data, and DNA samples have been collected from children and child–parent trios in 15 and 13 of these studies, respectively. Two registry-based studies and one study comprising hospital records routinely obtained at birth and/or diagnosis have limited interview data or biospecimens. Conclusions: CLIC provides a unique opportunity to fill gaps in knowledge about the role of environmental and genetic risk factors, critical windows of exposure, the effects of gene–environment interactions and associations among specific leukemia subtypes in different ethnic groups.     

Kinderculture: The Corporate Construction of Childhood

Kinderculture: The Corporate Construction of Childhood. Shirley R. Steinberg and Joe L. Kincheloe, eds. Boulder, CO: Westview Press, 1997. 270 pp.     

Small Wars: The Cultural Politics of Childhood

Small Wars: The Cultural Politics of Childhood. Nancy Scheper-Hughes and Carolyn Sargent. eds. Los Angeles: University of California Press, 1998. iv. 429 pp.     

儿童孤独症与拷贝数变异的研究

儿童孤独症是一种复杂的神经发育性障碍,患儿常表现有认知、情感和行为等多方面的异常,主要临床表现为社会交往障碍,言语交流障碍,重复刻板行为。孤独症多起病于三岁之前,男女发病比例约为4:1,患儿常伴有明显的精神发育迟滞。近年来,其发病率呈现逐年上升的趋势,最新的流行病学调查显示孤独症在美国的患病率约为9.1‰。据公认的假说"常见疾病-常见变异"推测,孤独症的风险等位基因和其他复杂疾病一样,在普通人群中将会变得很常见。由于该病起病早,难以进行早期识别,而且尚无特效药或方法可以彻底治愈这种病症,因而给社会及患儿家庭带来了沉重的负担。目前其发病原因和机制尚不明确,但关于儿童孤独症的双生子研究和家系研究都显示它是一个高度遗传性疾病,而且很多证据都表明孤独症是受多因素影响的遗传性疾病,近年来关于孤独症和拷贝数变异(CNVS)研究的报道越来越多,本文将主要就儿童孤独症的拷贝数变异研究现状和最新进展进行论述。     

The Changing Pattern of Rheumatic Fever in Childhood

The manifestations of acute rheumatic fever were compared in 231 children admitted to hospital from 1937 to 1940 with those in 252 children admitted from 1957 to 1960. Of the 178 in the early group seen during an initial attack, 82 had cardiac involvement; of these, 12 died early. Of the 218 patients in the later group with an initial attack, 96 had cardiac involvement; of these, two died early. Despite this decrease in early mortality, the incidence of isolated mitral value involvement (73% in the early group and 62% in the later group) and the incidence of congestive failure (20% and 13%) were similar. This reduction in the number of early deaths may be due to lowered virulence of the streptococcus, improved socioeconomic conditions, or therapy with penicillin and corticosteroids. The incidence of chorea and the frequency of recurrences were also less in the later group.     

Small Wars: The Cultural Politics of Childhood

Small Wars: The Cultural Politics of Childhood. Nancy Scheper-Hughes and Carolyn Sargent. eds. Berkeley: University of California Press, 1998. 429 pp.     

The Sequelae of Acute Purulent Meningitis in Childhood

Of a series of 122 children suffering from acute purulent meningitis at the Children''s Hospital, Winnipeg, in the years 1952-56, 12 (9.8%) succumbed, all deaths occurring in those 12 months of age or less. Fortyone of the survivors were re-studied 2.5 to 7.5 years after their acute illness to assess the nature and incidence of sequelae, the relationship of sequelae to the severity of the acute illness, and the correlation between the various methods of identifying sequelae. Five children exhibited psychiatric evidence of organic brain damage; seven, neurological abnormality; 11, electroencephalographic abnormality. Three had defective intelligence and nine psychological test evidence of organic brain damage. Children with sequelae tended to have several abnormal test results, the total number with neuropsychiatric and/or psychological sequelae being 11 (26%). There was a positive correlation between the severity of the acute illness and the presence of neuropsychiatric sequelae; also between neuropsychiatric sequelae, defective intelligence and psychological evidence of brain damage. No correlation existed between the electroencephalographic abnormality and neuropsychiatric defect.     

The Development of Higher Forms of Attention in Childhood

The history of attention in the child is the history of levels of the organization of his/her behavior. This history begins from the very moment of birth. Initially the child's attentional processes are carried out through inherited neurological mechanisms that organize the functioning of his/her reflexes in accordance with the well-known physiological principle of response dominance. This principle asserts that the organizing feature in the nervous system is a single, supreme center of stimulation whose strength grows at the expense of these inherited mechanisms. The dominant response provides the organic basis of the behavioral processes referred to as attention.