Genetic diversity analysis of isolates belonging to the Photobacterium phosphoreum species group collected from salmon products using AFLP fingerprinting

An accurate amplified fragment length polymorphism (AFLP) method, including three primer sets for the selective amplification step, was developed to display the phylogenetic position of Photobacterium isolates collected from salmon products. This method was efficient for discriminating the three species Photobacterium phosphoreum, Photobacterium iliopiscarium and Photobacterium kishitanii, until now indistinctly gathered in the Photobacterium phosphoreum species group known to be strongly responsible for seafood spoilage. The AFLP fingerprints enabled the isolates to be separated into two main clusters that, according to the type strains, were assigned to the two species P. phosphoreum and P. iliopiscarium. P. kishitanii was not found in the collection. The accuracy of the method was validated by using gyrB-gene sequencing and luxA-gene PCR amplification, which confirmed the species delineation. Most of the isolates of each species were clonally distinct and even those that were isolated from the same source showed some diversity. Moreover, this AFLP method may be an excellent tool for genotyping isolates in bacterial communities and for clarifying our knowledge of the role of the different members of the Photobacterium species group in seafood spoilage.

A mixed mode low profile solar tunnel dryer for canarium indicum nuts

Canarium indicum nuts are dried and consumed widely across the Pacific Region. Traditional methods of drying offer little process control resulting in highly variable product quality and loss. A more reliable and effective drying technology is required but the technology must suit local conditions. This paper describes a low profile solar tunnel dryer designed for batch drying of small quantities of the nuts. Prototypes have been tested. Experimental results indicate that drying temperatures are within the range to achieve good kernel quality and that the desired final moisture content for safe storage could be achieved after 30 hours of exposure.

Estudo da infeção de corvina (Argyrosomus regius Asso, 1801) por Photobacterium damselae subsp. piscicida

As práticas intensivas que são utilizadas em aquacultura implicam que exista um contacto extremo entre indivíduos promovendo o stress, que atuando conjuntamente com diversos outros fatores, como é o caso de bactérias, são passíveis de induzir nos peixes um estado de doença. Photobacterium damselae subsp. piscicida (Phdp) é uma bactéria gram-negativa reconhecida por causar surtos graves de doença em diversas espécies de peixes. É considerada mundialmente como uma das maiores enfermidades para as práticas aquícolas, plausível de causar danos irreversíveis nestas populações. Neste trabalho pretendeu-se elaborar um protocolo de infeção com Phdp em Argyrosomus regius estabelecendo num primeiro ensaio a dose que causa mortalidade a 50% de uma população (LD50), estudando posteriormente num segundo ensaio, a infeção, o destino que a bactéria teria no peixe através de análise PCR, as consequências da infeção a nível hematológico e nos parâmetros imunitários, utilizando um modelo de coabitação, expondo indivíduos saudáveis a indivíduos doentes. Foi comprovada a virulência da estirpe AQP 17.1 de Phdp sobre indivíduos da espécie A. regius com um peso médio de 28,3±10,9g, situando-se o LD50 em 2,29×105 UFC ml-1, apresentando os peixes alguns sintomas típicos da doença crónica. O modelo de coabitação utilizado no segundo ensaio, permitiu-nos confirmar que Phdp infetou por coabitação indivíduos da espécie A. regius com peso médio de 23,4±8,6g. Os resultados sugerem que as brânquias podem ter sido um dos locais de entrada da bactéria no corpo do peixe, disseminando-se após 24 horas para o rim e intestino anterior. Phdp induziu em A. regius uma resposta imune inata que se avaliou ao longo do tempo quando comparados os indivíduos coabitantes do controlo (vetores injetados com tampão salino de Hanks) com os indivíduos coabitantes infetados (vetores injetados com suspensão de Phdp a uma concentração igual ao LD50). Esta resposta inflamatória ficou visível não só no aumento do número de leucócitos no sangue, mas também no aumento de atividade dos parâmetros humorais imunes. Os resultados sugerem que a maior atividade da resposta imunitária se deu após as 24 horas de coabitação, momento que determina também a invasão do patógeno em órgãos como o intestino anterior e o rim. Os resultados obtidos neste trabalho sugerem que Phdp pode induzir um estado de infeção em A. regius através de um modelo de coabitação, invadindo num curto espaço de tempo os órgãos do hospedeiro, desencadeando a atividade do sistema imune inato como resposta à infeção.

Tropical dryland agroforestry on clay soils: : Analysis of systems based on Acacia senegal in the Blue Nile region, Sudan

Acacia senegal, the gum arabic producing tree, is the most important component in traditional dryland agroforestry systems in the Blue Nile region, Sudan. The aim of the present study was to provide new knowledge on the potential use of A. senegal in dryland agroforestry systems on clay soils, as well as information on tree/crop interaction, and on silvicultural and management tools, with consideration on system productivity, nutrient cycling and sustainability. Moreover, the aim was also to clarify the intra-specific variation in the performance of A. senegal and, specifically, the adaptation of trees of different origin to the clay soils of the Blue Nile region. In agroforestry systems established at the beginning of the study, tree and crop growth, water use, gum and crop yields, nutrient cycling and system performance were investigated for a period of four years (1999 to 2002). Trees were grown at 5 x 5 m and 10 x 10 m spacing alone or in mixture with sorghum or sesame; crops were also grown in sole culture. The symbiotic biological N2 fixation by A. senegal was estimated using the 15N natural abundance (δ15N) procedure in eight provenances collected from different environments and soil types of the gum arabic belt and grown in clay soil in the Blue Nile region. Balanites aegyptiaca (a non-legume) was used as a non-N-fixing reference tree species, so as to allow 15N-based estimates of the proportion of the nitrogen in trees derived from the atmosphere. In the planted acacia trees, measurements were made on shoot growth, water-use efficiency (as assessed by the δ13C method) and (starting from the third year) gum production. Carbon isotope ratios were obtained from the leaves and branch wood samples. The agroforestry system design caused no statistically significant variation in water use, but the variation was highly significant between years, and the highest water use occurred in the years with high rainfall. No statistically significant differences were found in sorghum or sesame yields when intercropping and sole crop systems were compared (yield averages were 1.54 and 1.54 ha-1 for sorghum and 0.36 and 0.42 t ha-1 for sesame in the intercropped and mono-crop plots, respectively). Thus, at an early stage of agroforestry system management, A. senegal had no detrimental effect on crop yield, but the pattern of resource capture by trees and crops may change as the system matures. Intercropping resulted in taller trees and larger basal and crown diameters as compared to the development of sole trees. It also resulted in a higher land equivalent ratio. When gum yields were analysed it was found that a significant positive relationship existed between the second gum picking and the total gum yield. The second gum picking seems to be a decisive factor in gum production and could be used as an indicator for the total gum yield in a particular year. In trees, the concentrations of N and P were higher in leaves and roots, whereas the levels of K were higher in stems, branches and roots. Soil organic matter, N, P and K contents were highest in the upper soil stratum. There was some indication that the P content slightly increased in the topsoil as the agroforestry plantations aged. At a stocking of 400 trees ha-1 (5 x 5 m spacing), A. senegal accumulated in the biomass a total of 18, 1.21, 7.8 and 972 kg ha-1of N, P, K and OC, respectively. Trees contributed ca. 217 and 1500 kg ha-1 of K and OC, respectively, to the top 25-cm of soil over the first four years of intercropping. Acacia provenances of clay plain origin showed considerable variation in seed weight. They also had the lowest average seed weight as compared to the sandy soil (western) provenances. At the experimental site in the clay soil region, the clay provenances were distinctly superior to the sand provenances in all traits studied but especially in basal diameter and crown width, thus reflecting their adaptation to the environment. Values of δ13C, indicating water use efficiency, were higher in the sand soil group as compared to the clay one, both in leaves and in branch wood. This suggests that the sand provenances (with an average value of -28.07 ) displayed conservative water use and high drought tolerance. Of the clay provenances, the local one (Bout) displayed a highly negative (-29.31 ) value, which indicates less conservative water use that resulted in high productivity at this particular clay-soil site. Water use thus appeared to correspond to the environmental conditions prevailing at the original locations for these provenances. Results suggest that A. senegal provenances from the clay part of the gum belt are adapted for a faster growth rate and higher biomass and gum productivity as compared to provenances from sand regions. A strong negative relationship was found between the per-tree gum yield and water use efficiency, as indicated by δ13C. The differences in water use and gum production were greater among provenance groups than within them, suggesting that selection among rather than within provenances would result in distinct genetic gain in gum yield. The relative δ15N values ( ) were higher in B. aegyptiaca than in the N2-fixing acacia provenances. The amount of Ndfa increased significantly with age in all provenances, indicating that A. senegal is a potentially efficient nitrogen fixer and has an important role in t agroforestry development. The total above-ground contribution of fixed N to foliage growth in 4-year-old A. senegal trees was highest in the Rahad sand-soil provenance (46.7 kg N ha-1) and lowest in the Mazmoom clay-soil provenance (28.7 kg N ha-1). This study represents the first use of the δ15N method for estimating the N input by A. senegal in the gum belt of Sudan. Key words: Acacia senegal, agroforestry, clay plain, δ13C, δ15N, gum arabic, nutrient cycling, Ndfa, Sorghum bicolor, Sesamum indicum

An ethnobotanical study of traditional anti-inflammatory plants used by the Lohit community of Arunachal Pradesh, India

Aim of the study: Most people especially in rural areas depend on herbal medicines to treat many diseases including inflammation-related ailments such as rheumatism, muscle swelling, cut wound, accidental bone fracture, insect bites, pains and burn by fire and hot water. The objectives of this study were: to catalog ethno-medicinal plants of Lohit community, ecological status, indigenous folk medicinal uses, morphological parts used and to determine their reported pharmacological studies. Materials and methods: The ethnobotanical information on traditional medicinal plants exclusively used for management of inflammation-related ailments by the Khampti community of Arunachal Pradesh, India was based on first-hand field survey work through semi-structured interviews. Results and conclusion: A total of 34 species in 32 genera and 22 families were encountered during the field survey. Botanical families such as Asteraceae, Euphorbiaceae, Zingiberaceae and Lamiaceae were represented by the highest numbers of species reported in this study. Thirteen plant species, namely: Bombax ceiba, Canarium strictum, Chloranthus erectus, Xanthium indicum, Lycopodium clavatum, Coleus blumei, Batrachospermum atrum, Chlorella vulgaris, Marchantia palmata, Marchantia polymorpha, Eria pannea, Sterculia villosa and Alpinia galanga are reported for the first time for the treatment of inflammation-related diseases.

Karyotype instability in the ponerine ant genus Diacamma

The queenless ponerine ant Diacamma ceylonense and a population of Diacamma from the Nilgiri hills which we refer to as `nilgiri', exhibit interesting similarities as well as dissimilarities. Molecular phylogenetic study of these morphologically almost similar taxa has shown that D ceylonense is closely related to `nilgiri' and indicates that `nilgiri' is a recent diversion in the Diacamma phylogenetic tree. However, there is a striking behavioural difference in the way reproductive monopoly is maintained by the respective gamergates (mated egg laying workers), and there is evidence that they are genetically differentiated, suggesting a lack of gene flow To develop a better understanding of the mechanism involved in speciation of Diacamma, we have analysed karyotypes of D. ceylonense and `nilgiri' In both, we found surprising inter-individual and intra-individual karyotypic mosaicism. The observed numerical variability, both at intra-individual and inter-individual levels, does not appear to have hampered the sustainability of the chromosomal diversity in each population under study Since the related D. indicum, displays no such intra-individual or inter-Individual variability whatsoever under identical experimental conditions, these results are unlikely to he artifacts. Although no known mechanisms can account for the observed karyotypic variability of this nature, we believe that the present findings on the ants under study would provide opportunities for exciting new discoveries concerning the origin, maintenance and significance of intra-individual and inter-individual karyotypic mosaicism.

Ethnobotany of the Monpa ethnic group at Arunachal Pradesh, India

Background: The present paper documents the uses of plants in traditional herbal medicine for human and veterinary ailments, and those used for dietary supplements, religious purpose, local beverage, and plants used to poison fish and wild animals. Traditional botanical medicine is the primary mode of healthcare for most of the rural population in Arunachal Pradesh. Materials and methods: Field research was conducted between April 2006 and March 2009 with randomly selected 124 key informants using semi-structured questionnaire. The data obtained was analyzed through informant consensus factor (F(IC)) to determine the homogeneity of informant's knowledge on medicinal plants. Results: We documented 50 plants species belonging to 29 families used for treating 22 human and 4 veterinary ailments. Of the medicinal plants reported, the most common growth form was herbs (40%) followed by shrubs, trees, and climbers. Leaves were most frequently used plant parts. The consensus analysis revealed that the dermatological ailments have the highest F(IC) (0.56) and the gastro-intestinal diseases have F(IC) (0.43). F(IC) values indicated that there was high agreement in the use of plants in dermatological and gastro-intestinal ailments category among the users. Gymnocladus assamicus is a critically rare and endangered species used as disinfectant for cleaning wounds and parasites like leeches and lice on livestocks. Two plant species (Illicium griffithii and Rubia cordifolia) are commonly used for traditional dyeing of clothes and food items. Some of the edible plants recorded in this study were known for their treatment against high blood pressure (Clerodendron colebrookianum), diabetes mellitus (Momordica charantia), and intestinal parasitic worms like round and tape worms (Lindera neesiana, Solanum etiopicum, and Solanum indicum). The Monpas of Arunachal Pradesh have traditionally been using Daphne papyracea for preparing hand-made paper for painting and writing religious scripts in Buddhist monasteries. Three plant species (Derris scandens, Aesculus assamica, and Polygonum hydropiper) were frequently used to poison fish during the month of June-July every year and the underground tuber of Aconitum ferrox is widely used in arrow poisoning to kill ferocious animals like bear, wild pigs, gaur and deer. The most frequently cited plant species; Buddleja asiatica and Hedyotis scandens were used as common growth supplements during the preparation of fermentation starter cultures. Conclusion: The traditional pharmacopoeia of the Monpa ethnic group incorporates a myriad of diverse botanical flora. Traditional knowledge of the remedies is passed down through oral traditions without any written document. This traditional knowledge is however, currently threatened mainly due to acculturation and deforestation due to continuing traditional shifting cultivation. This study reveals that the rural populations in Arunachal Pradesh have a rich knowledge of forest-based natural resources and consumption of wild edible plants is still an integral part of their socio-cultural life. Findings of this documentation study can be used as an ethnopharmacological basis for selecting plants for future phytochemical and pharmaceutical studies.

An inventory of the ethnobotanicals used as anti-diabetic by a rural community of Dhemaji district of Assam, Northeast India

Ethnopharmacological relevance: Traditional remedies used for treating diabetic ailments are very important in the primary health care of the people living in rural Dhemaji district of Assam, north-east India. Novel information gathered from the current survey is important in preserving folk indigenous knowledge. Materials and methods: Interviews were conducted amongst 80 households comprising of 240 individuals using semi-structured questionnaires. The focus was on plants used in treating diabetes mellitus. Results: The current survey documented 21 plant species (20 families) which are reportedly used to treat diabetes mellitus by the rural people in the study area. To the best of our knowledge, Amomum linguiforme, Cinnamomum impressinervium, Colocasia esculenta, Dillenia indica, Euphorbia ligularia, Garcinia pedunculata, Solanum indicum, Sterculia villosa and Tabernaemontana divaricata are recorded for the first time based on globally published literature as medicinal plants used for treating diabetes mellitus and related symptoms. Conclusions: The wide variety of plants that are used to treat diabetes mellitus in this area supports the traditional value that medicinal plants have in the primary health care system of the rural people of Dhemaji district of Assam. The finding of new plant uses in the current study reveals the importance of the documentation of such ethnobotanical knowledge. (C) 2011 Elsevier Ireland Ltd. All rights reserved.

Caracterización de sistemas de producción ganadera en las Comarcas de Copalar y San Pedro del Norte, Municipio de Bocanas de Paiwás, Zelaya Central

El presente trabajo se realizó con el objetivo de contribuir al desarrollo ganadero del micro región por medio de la caracterización de las actividades ganaderas de las Comarcas de Copalar y San Pedro del norte. El estudio se llevó a cabo en dos fases: Una fase preliminar de “diagnóstico, en la que se determinó, la disponibilidad y uso actual de los recursos en las fincas, tecnologías y características generales de los canales de comercialización y precios de los productos pecuarios generados por la actividad ganadera de las Comarcas. La segunda fase comprendió el procesamiento y computación de la información. La información relativa a los recursos pecuarios se procesó para cada uno de los eslabones de la cadena y en base a ello se estimaron los diferentes parámetros técnicos, productivos, reproductivos y elementos fuentes de ingresos y egresos determinándose así la rentabilidad de cada uno de los eslabones de la cadena. En los aspectos técnicos se determinó que la actividad de las fincas es la ganadería; ya que en promedio, el 92% de las áreas totales se destinan a esta actividad; existiendo solamente pastos naturales. Las cargas animales encontradas fluctuaron en un rango de 0.24 u.a/mz a 0.49 u.a/mz, siendo inferiores a las disponibilidades de pastos ; resultando las disponibilidades positivas. Las especies de pastos encontrados en mayor proporción en estas fincas son Asia (Panicum maximum) y Retana (Ischaemun indicum). En cuanto al manejo de potreros; encontramos que presentan un área promedio por potrero entre 27-29 mz. y realizan rotación de potreros cada 15-30 días. En relación al control de maleza se realizan chapeas más rondas dos veces al año y quemas cada dos, tres años.

Viability of seeds in food products proposed for field trips in Galapagos

Seeds of 14 plant species extracted from food products proposed for field trips in Galapagos were tested for viability. Strawberry Fragaria ananasa and Blackberry Rubus glaucus jams (Snob and Gustadina brands) contained no viable seeds. Schullo brand granola contained inviable Sesame Sesamum indicum seed, but Sesame in granolas prepared in Galapagos was viable. Sesame seed in bread was viable but Flax Linum usitatissimum seed in bread was not. Brown Rice Oryza sativa and Sunflower seeds Helianthus annuus were both viable. Fresh Apple Malus domestica, Naranjilla Solanum quitoense, Cucumber Cucumis sativus, Pineapple Ananas comosus, Pear Pyrus communis, Bell Pepper Capsicum annuum, Tomato Solanum lycopersicum, Grape Vinis vinifera all contained viable seeds. We recommend prohibiting any product with viable seeds from field trips to uninhabited areas. CDF Contribution Number 1009.

Antibacterial effect of the Indian squid, Loligo duvauceli (d'Orbigny), ink

The ink of the Indian squid Loligo duvauceli (d'Orbigny) was tested for antibacterial activity. The antibacterial effect of bacteria present in the ink gland was also tested. Only one type of bacteria was found to be present in the ink gland of squid and was identified as Photobacterium leiognathi. Among the various forms of ink extracts, the precipitated and freeze-dried ink showed more pronounced antibacterial effect against Gram-negative bacteria, Salmonella, spp. Escherichia coli, Vibrio cholerae, V. parahaemolyticus and Pseudoinonas spp., and a less pronounced effect against Gram-positive bacteria, Staphylococcus spp. and Micrococcus spp., P. leiognathi did not inhibit any of the above bacteria. The antibacterial activity was associated with the compounds of the ink.

Distribution of drug resistant luminous bacteria in penaeid shrimp grow-out ponds

Distribution of luminous bacteria (LB) in penaeid shrimp grow-out pond water in semiintensive seawater farming system and their resistance to 15 antibacterials were investigated. Total viable counts and luminous bacterial counts in pond water ranged from 2.00xl03 to 1.35xl04/ml and l.OOxl01 to 8.00Xl02/ml, respectively. The percentage composition of LB in the total viable population increased significantly with period of culture. Five species of LB such as Vibrio fischeri, V. harveyi, V. orientalis, V. splendidus 1 and Photobacterium leiognathi were encountered. V. harveyi was the dominant species, constituting >80% of the total LB. Multiple antibiotic resistance was more common in these LB. Pond water isolates showed resistance to at least four antibacterial agents.

五种毛壳霉属和曲霉属真菌代谢产物及细胞毒活性

毛壳霉属(Chaetomium)和曲霉属(Aspergillus)真菌产生多种具有生物活性的化合物。为系统阐明两属微生物的次生代谢物，对三种毛壳霉、两种曲霉真菌分别进行固态发酵，以色谱和波谱技术研究发酵物中的成分，分离鉴定了51个化合物，其中23个为新化合物，测试了部分化合物对肿瘤细胞的活性。 1、从螺卷毛壳霉（C. cochloides）固态发酵物中分离鉴定了11个化合物，3个新化合物为螺卷毛壳霉素A~C（1~3）。化合物1、3及dethio-tetra (methylthio) chetomin（4）对Bre-04、Lu-04和N-04细胞株生长抑制的GI50值为0.05~7.0 μg/mL。 2、从印度毛壳霉（C. indicum）固态发酵物中鉴定的三个异喹啉生物碱印度毛壳霉素A~C（12~14）代表两类骨架新颖的异喹啉生物碱。 3、从巴西毛壳霉（C. brasiliense）固态发酵物中鉴定了11个化合物，其中Mollicellins I~J（15~16）、2-Hydroxymethyl-6-methylmethyleugenin（19）为新化合物。化合物16和Mollicellin H（18）对Bre-04、Lu-04、N-04细胞株生长抑制的GI50值在2.5~8.6 μg/mL。 4、从土曲霉（A. terreus）固态发酵物中鉴定了18个化合物。5个为新化合物为Terretonin A~D（24~27）和Asterrelenin（28），24~27为二倍半萜化合物，28为吲哚生物碱。 5、从杂色曲霉(A. versicolor）固态发酵物中鉴定了16个化合物。9个新的化合物Brevianamides K~N (40~43)、Averins A~C (44~46)和Glyanphenines A~B (47~48)代表三种类型的生物碱。 6、综述了1997－2007年间新的二倍半萜的研究进展。 The fungi of the genera Chaetomium and Aspergillus produce various secondary metabolites with biological activities. In order to systematically study the secondary metabolites, the solid-state fermented rice culture of three species of Chaetomium and two of Aspergillus were chemically studied. By the means of chromatograhy and spectroscopy, 55 compounds were isolated and identified, among of them 23 were new ones. The biological activities of some compounds were investigated. 1. From the fungus C. cochliodes, three new epipolythiodioxopiperazines, chaetocochins A-C (1-3) were isolated, together with 8 known ones (4-11). Compounds 1, 3 and 4 showed growth inhibitory effects against cancer cell lines Bre-04, Lu-04 and N-04 with GI50 values from 0.05 to 7.0 μg/mL. 2. Three novel isoquinolines Chaetoindicins A-C (12-14) were isolated and identified from the fungus C. indicum. Chaetoindicin A, Chaetoindicins B-C represented two classes of novel carbon skeletons. 3. Three new compounds, Mollicellins I-J (15-16), and 2-hydroxymethyl-6-methylmethyleugenin (19), were isolated from C. brasiliense. Compound 16 and Mollicellin H (18) showed growth inhibitory effects against cancer cell lines Bre-04, Lu-04 and N-04 with GI50 values from 2.5 to 8.6 μg/mL. 4. Eighteen compounds were isolated from the fungus A. terreus. Terretonin A-D（24 - 27）and Asterrelenin（28） are new compounds belonging to sesterterpoids and indole-ralated alkaloid, respectively. 5. From the fungus A. versicolor, sixteen secondary metabolites, including nine new ones, Brevianamides K-N (40-43), Averins A-C (44-46), and Glyanphenines A-B (47-48), were isolated and identified. Brevianamides K-N (40-43), Averins A-C (44-46), and Glyanphenines A-B (47-48) represented three classes of alkaloids. 6. New sesterterpenes and their bioactivities reported from 1997 to 2007 were summarized.

织纹螺（Nassarius spp.）体内河豚毒素来源的研究

近几十年来，国内沿海地区频繁发生食用织纹螺中毒事件，并导致数十人死亡，这一问题得到了政府相关部门的高度重视。但是，由于织纹螺毒性变化很大，毒素来源不清楚，因此很难预测食用织纹螺中毒事件的发生，这在很大程度上限制了对食用织纹螺中毒事件的有效监测和管理。目前，对于中国沿海有毒织纹螺体内河豚毒素（tetrodotoxin, TTX）的来源还未见过系统研究。本文选取中国沿海常见的半褶织纹螺（Nassarius semiplicatus）、纵肋织纹螺（N. variciferus）和拟半褶织纹螺（N. semiplicatoides sp. nov.）作为实验对象，从毒素的微生物来源与食物链来源这两个角度分别展开研究，以探讨织纹螺体内 TTX 的可能来源，为提出相应的预防管理措施提供科学依据。 首先，我们先后从曾发生过中毒事件的江苏盐城和连云港采集了织纹螺样品，通过小鼠生物测试法和液-质联用分析技术（LC-MS），对织纹螺的毒性和毒素组成进行了测试和分析，分离培养了织纹螺体内及其生活环境中的细菌，应用河豚毒素单克隆抗体酶联免疫检测方法（ELISA）对细菌的产毒情况进行了测试，并通过 16S 核糖体（rRNA）部分基因序列测定对细菌种类进行了初步的分析。研究发现，采自江苏盐城和连云港的半褶织纹螺的毒性分别约为 2 MU/g 和 200 MU/g 组织，体内的毒素成分是河豚毒素及其同系物。从盐城的半褶织纹螺及其生活环境分离的菌株中随机挑出 14 个菌株中，9 个菌株河豚毒素检测结果呈现阳性。从连云港高毒性半褶织纹螺消化腺中分离到的 45 个菌株中，阳性菌株有 21 个。但是，有毒菌株毒素含量较低，毒素含量范围是 15-184ng/g。通过 16S rDNA 部分序列的测序结果发现，大部分有毒菌株与弧菌属（Vibrio）的细菌在遗传序列信息上比较相近。其余有毒菌株分别与希瓦氏菌属（Shewanella）、海单胞菌属（Marinomonas）、黄杆菌属（Tenacibaculum）、动性菌属（Planococcus）、发光杆菌属 (Photobacterium)和气单胞菌属（Aeromonas）的遗传序列比较相近。其中与海单胞菌属、动性菌属和发光杆菌属亲缘关系较近的产毒细菌是首次报道。这一研究表明织纹螺体内及其生活环境中的存在产河豚毒素的细菌，但由于产毒素的量较低，因此可能在织纹螺体内河豚毒素的产生和累积过程并不发挥主要作用。 织纹螺作为一类腐食性的海洋动物，也有可能通过进食含有河豚毒素的生物而累积河豚毒素。对此，我们开展了高毒性半褶织纹螺的室内培养实验，以及河豚毒素在不同种类织纹螺体内的累积和排出的模拟实验，并定期采样，通过液相色谱与串联质谱联用技术（LC-MS/MS）对织纹螺体内河豚毒素及其同系物的含量变化情况进行了分析。室内培养实验发现，从连云港赣榆县采集的高毒性半褶织纹螺，在实验初期，体内毒素含量呈下降的趋势，但从 7月上旬开始，毒素含量突然快速上升，与连云港赣榆县野外采集的织纹螺的毒素含量表现出相似的变化趋势。河豚毒素在不同种织纹螺体内的累积和排出的模拟实验发现，通过投喂高毒性的河豚鱼肝脏（毒性为5×103 MU/g），纵肋织纹螺在一段时间内能够快速累积少量的河豚毒素。当停止投喂有毒河豚鱼肝脏后，毒素含量会快速下降。而在曾导致中毒事件的拟半褶织纹螺中，投喂有毒河豚鱼的肝脏后，其体内毒素含量只有缓慢增加。但在投喂无毒的河豚鱼肝脏后，其毒性却出现了快速增加的现象，这与该地区野外样品的毒性变动状况类似。这些发现显示高毒性半褶、拟半褶织纹螺体内的河豚毒素应当不是食物链累积的结果，而可能是由其自身产生。并且，毒素含量的变化具有一定的生物节律，有可能与产卵、繁殖等自然节律相关。 通过对半褶、纵肋和拟半褶织纹螺的研究工作可以认为，产河豚毒素的细菌不是织纹螺体内河豚毒素的主要来源，并且毒素也不是来自其摄食的食物，推测可能主要是由织纹螺自身产生。织纹螺所表现出的河豚毒素含量的季节性变化，极有可能与产卵、繁殖等自然节律相关，这些发现为预防和管理食用织纹螺中毒事件提供了科学依据。但是，本研究并未完全阐明织纹螺体内河豚毒素的来源，对于织纹螺体内河豚毒素的确切来源以及河豚毒素的代谢和转化机制，还有待于更加深入地研究工作。

CNPA G3: nova opção de gergelim para a região do Distrito Federal.

2001