Infection of Artemia salina by Haliphthoros milfordensis: A scanning and transmission electron microscope study

The fungus Haliphthoros milfordensis is a known pathogen of cultured lobster (W. S. Fisher, E. H. Nilson, and R. S. Schleser, 1975, J. Invertebr. Pathol., 26, 41–45) and has been isolated also from gills of the white shrimp (T. P. Tharp and C. E. Bland, 1977, Canad. J. Bot.55, 2936–2944). Because of the potential impact of this fungus on culture of commercially important marine crustacea, a model laboratory system involving Artemia salina has been devised to study aspects of its biology. This report describes light and electron microscope observations of the infection process and the internal relationship between host and parasite. Following encystment of zoospores on the exoskeleton of larvae, infection occurs via germination of the spore and penetration of the exoskeleton and epidermis by vegetative hyphae. Growth of the fungus destroys first fat and body muscles and ultimately the gut. Electron-dense material at the host-parasite interface is likely a response of the shrimp to invading fungal hyphae. Histolytic activity by the fungus is evident by the dissolution of host cytoplasm along the growing hyphal tips. Following utilization of all host tissues, hyphae grow to the exterior and the process of sporulation is initiated.     

Streptomyces sp. 173, an insecticidal micro-organism from marine

AIMS: To find new insecticidal antibiotics from marine micro-organisms. METHODS AND RESULTS: Strains isolated from seawater and sea sediments from Beidiahe and Dagang of the east coast of China were screened for their insecticidal qualities. The screening was carried out using bioassay of brine shrimp and the insect pest Helicoverpa armigera. The fermentation, preliminary extraction and isolation of Streptomyces sp.173 were carried out. CONCLUSIONS: In total 331 isolates were examined through bioassay of brine shrimp and 40 isolates (12.08%) showed potential insecticidal activities. Of the 40 isolates, one isolate, designated Streptomyces sp.173, was found to have strong insecticidal activity against both brine shrimp and H. armigera, similar to that of avermectin B1. SIGNIFICANCE AND IMPACT OF THE STUDY: The isolated Streptomyces sp.173 has great insecticidal potency. This work indicated that marine micro-organisms could be an important source of insecticidal antibiotics and the improved anti-brine shrimp bioassay is suitable for primary screening.     

Immunological relationships between Artemia RNA polymerases and between RNA polymerases II from different eukaryotic organisms

Summary Rabbit antibodies against Artemia RNA polymerase II have been raised and utilized to study the immunological relationships between the subunits from RNA polymerases I, II and III from this organism and RNA polymerase II from other eukaryotes. We describe here for the first time the subunit structure of Artemia RNA polymerases I and III. These enzymes have 9 and 13 subunits respectively. The anti-RNA polymerase II antibodies recognize two subunits of 19.4 and 18 kDa common to the three enzymes, and another subunit of 25.6 kDa common to RNA polymerases II and III. The antibodies against Artemia RNA polymerase II also react with the subunits of high molecular weight and with subunits of around 25 and 33 kDa of RNA polymerase II from other eukaryotes (Drosophila melanogaster, Chironomus thummi, triticum (wheat) and Rattus (rat)). This interspecies relatedness is a common feature of eukaryotic RNA polymerases.Abbreviations RNAp RNA polymerase - DPT diazophenylthioether - SDS sodium dodecylsulfate     

Poly-beta-hydroxybutyrate-accumulating bacteria protect gnotobiotic Artemia franciscana from pathogenic Vibrio campbellii

A poly-beta-hydroxybutyrate (PHB)-accumulating enrichment culture was obtained using activated sludge from a polyphosphate-accumulating reactor as inoculum. PHB accumulated by the enrichment culture significantly enhanced the survival of Artemia nauplii, infected with the virulent pathogen Vibrio campbellii LMG 21363. A strain was isolated from the enrichment culture, based on its ability to accumulate PHB, and 16S rRNA gene sequencing of the isolate revealed 99% sequence similarity to Brachymonas denitrificans AS-P1. The isolate, named PHB2, showed good PHB-accumulating activity (up to 32% of the cell dry weight). PHB accumulated by isolate PHB2 was able to protect Artemia completely from the V. campbellii strain. Our data indicate that PHB-accumulating bacteria, such as B. denitrificans PHB2, could be used as an an effective and economically interesting alternative strategy to control infections in aquaculture.     

Review of the biogeography of the genus Artemia (Crustacea, Anostraca)

In this study, we report on the known Artemia habitats worldwide. Recent literature information is incorporated about the taxonomic status of the various populations studied. The genus is composed of di-, tri-, tetra- and pentaploid parthenogenetic populations and of the following bisexual species: A. franciscana franciscana , A. franciscana monica , A. franciscana sp., A. persimilis , A. salina , A. urmiana , A. sinica and A. sp. from Kazakhstan. The problems of characterizing new brine shrimp populations are discussed. In view of the great importance of Artemia as part of the live food chain for the culture of fish and shellfish larvae and the present cyst shortage from the market, the need for commercial exploitation and development of new Artemia sources is now, more than ever, necessary.     

Unprecedented derivatization of ferulic acid through selective methoxylation by Aspergillus brasiliensis ATCC 16404

Ferulic acid (FA) is a natural hydroxycinnamic acid widely found in medicinal and edible plants. Several experts have reported the biological potential of FA, including antioxidant and antimicrobial activities. The use of microorganisms in the derivatization of natural products is a useful and advantageous approach to the achievement of high value-added compounds. In order to access chemical derivatives, we conducted the biotransformation of FA by Aspergillus brasiliensis ATCC 16404 for 5 d. In the second day of fermentation, the FA was converted into the new (E)-3-(4-hydroxy-3-methoxyphenyl)-2-methoxyacrylic acid. This is the first time that the extended π-conjugation remained in the chemical structure after the biotransformation of FA. The cytotoxicities of FA and its derivative were evaluated. The biotransformation yielded a derivative less toxic than the parent compound.     

霸王鞭乙酸乙酯部分化学成分研究

为了研究霸王鞭(Euphorbia royleana Boiss.)的化学成分及其卤虫致死活性,采用正相硅胶柱色谱、Sephadex LH-20凝胶柱色谱及半制备型高效液相色谱等方法从霸王鞭甲醇提取物的乙酸乙酯萃取部位中分离得到15个化合物。通过现代波谱学技术鉴定它们的结构分别为5(6)-guten-3α-ol(1)、蒲公英赛醇(2)、异蒲公英赛醇(3)、熊果酸(4)、齐墩果酸(5)、1-羟基-3,7,8-三甲氧基黄酮(6)、甲基獐牙菜素(7)、槲皮素(8)、胡萝卜苷(9)、β-谷甾醇(10)、豆甾醇(11)、香草醛(12)、十二烷醇(13)、植物醇(14)、1-[(12 E,16 E)-12,16-二十碳二烯酰基]-2-[(E,E)-7,11-十八碳二烯酰基]-3-硬脂酰基甘油(15)。化合物1、3、4、5、6、7、12、13、14和15均首次从该植物中分离得到。对所得到的化合物进行了卤虫致死活性研究,发现化合物4表现出较强卤虫致死活性,其LD₅₀为7.687μM。     

Using the Kalanchoe daigremontiana Plant to Show the Effects of Photoperiodism on Plantlet Formation

The brine shrimp activity fosters authentic scientific inquiry in addition to providing an engaging and exciting avenue for student exploration. Students in grades 5–12 can use a plethora of science process skills as they design their own investigations. The activity, designed around a 5-E Learning Cycle model, supports the recommendations of the National Science Education Standards, which emphasize that inquiry should be a critical component in the science classroom.     

Ontogeny of low molecular weight stress protein p26 during early development of the brine shrimp, Artemia franciscana

Embryogenesis in the brine shrimp, Artemia sp., occurs by one of two pathways: (i) the direct, uninterrupted development of nauplius larvae within the female or (ii) the production of embryos that arrest development at the gastrula stage and enter diapause. Diapause embryos are released from females into the aqueous environment where they remain in diapause until activated by appropriate environmental cues and resume development. These encysted embryos possess at least one low molecular weight stress protein, which we refer to as p26 and which has been implicated previously in the stress response of activated embryos. We investigated the appearance of p26 in developing diapause embryos in utero and looked for its presence in embryos developing directly into nauplii. We found p26 to be specific to diapause-destined embryos; it was not detected in direct-developing embryos. We conclude that p26 is not required for the basic developmental program that produces the nauplius. In diapause-destined embryos, p26 was first detectable after 3 days of development, at which time the embryos were late gastrulae. This protein continues to increase in amount until the encysted embryos are released, approximately 5 days after fertilization. At the time of release almost all p26 is located in the low speed supernatant fraction, but as released embryos continue diapause, p26 transfers to the pelleted nuclear fraction in increasing amounts. Our working hypothesis views p26 as a molecular chaperone preventing protein denaturation and aggregation under conditions associated with metabolic arrest and other stressful states, which these encysted embryos encounter.     

海洋链霉菌S09的化学成分研究(英文)

从海洋链霉菌S09的发酵液提取物中分离得到6个化合物,通过波谱技术分别鉴定为:thymidine(1)、尿嘧啶(2)、3-甲基-2,5-哌嗪二酮(3)、2-吡咯甲酸(4)、卡拉霉素(5)和β-咔啉(6)。海虾致死实验结果显示:化合物5在10μg/mL的浓度下对丰年虾的致死率为87.6%,显示出较强的细胞毒活性。     

Nearshore and pelagic abundances of Artemia monica in Mono Lake,California

The spatial distribution and abundance of the brine shrimp, Artemia monica, in Mono Lake, California were determined during 1982 and 1983. Peak abundances of shrimp occur in midsummer and reach densities of 15–17 individuals l^-1 in the nearshore regions and 6–8 individuals 1^-1 in the pelagic region. The brine shrimp were non-uniformly distributed both vertically and horizontally. The coefficient of variation in shrimp abundance among stations within the nearshore region was similar to that found in the pelagic region. On two of the nine dates, nearshore densities were 3 to 4 times greater than those in the pelagic zone, and on average the brine shrimp appear to be slightly over-dispersed to the nearshore region. However, including nearshore abundances in lakewide estimates will usually result in a change of less than a 10%.