Anthropophilic blackflies (Diptera: Simuliidae) and onchocerciasis transmission in southwest Ethiopia

Abstract. From May 1984 to May 1985, the transmission of onchocerciasis by blackflies (Dipteria: Simuliidae) was studied around Gilgel Ghibe and Gojeb rivers in southwest Ethiopia. The predominant anthropophilic species of Simulium at both localities were S.(Edwardsellum) damnosum sensu law and S.(Lewisellum) ethiopiense. Some S.(Anasolen) dentulosum also landed on human bait at Gilgel Ghibe river.
Dissections of S. damnosum from Gilgel Ghibe and Gojeb revealed mean parous rates of 92% (n = 18,291) and 84% (n = 9530), respectively. S. ethiopiense from Gilgel Ghibe and Gojeb showed mean parous rates of 53% (n = 322) and 93% (n = 14), respectively. Of the parous S. damnosum , 1.3% at Gilgel Ghibe and 0.5% at Gojeb harboured infective third-stage larvae (L3) of Onchocerca volvulus (or morphologically indistinguishable from it). Unknown filariae of animal origin, indicative of zoophily, were found in 0.3% and 0.7% of Simulium damnosum complex females from Gilgel Ghibe and Gojeb, respectively. S. ethiopiense harboured developing (L,) larvae only, with 7.7% infection rate in both localities. In contrast, S. dentulosum did not harbour any filaria larvae. The annual infective biting rate (AIBR) and transmission potential (ATP) of the S. damnosum complex at Gilgel Ghibe river were 858 and 5478, respectively. The AIBR and ATP of S. damnosum s.I. at Gojeb river were 519.5 and 1963, respectively. These results emphasize the predominant role of the S. damnosum complex in the transmission of O. volvulus in southwest Ethiopia     

Quantification of SSB protein in E. coli and its variation during RECA protein induction

Using a two-site immunometric assay (IRMA) we quantified the concentration of single-stranded DNA binding protein (SSB) in several E. coli strains. We found approximately 7,000 monomers of SSB present per bacterium, and this number remained constant throughout the exponential phase of growth. Two ssb- mutants (ssb-1 and ssb-113) are defective in the induction of the S.O.S. pathway. One of the first functions expressed upon induction of the S.O.S. pathway is the amplification of recA protein (RECA), which we monitored by an IRMA assay similar to the one used for SSB quantification. By combining the two assays we determined the level of SSB and RECA in ssb- mutants or in SSB and RECA overproducer strains. We found: a) a normal induction of RECA following UV irradiation of E. coli bacteria overproducing SSB, b) a normal level of SSB in wild type and ssb-1 and ssb-113 mutants either in the absence or in the presence of S.O.S. inducing agents. We confirmed a severe impairment in the induction of RECA in these two mutants after nalidixic acid treatment. Our results suggest that the concentrations of RECA and SSB protein in E. coli are regulated by independent biochemical pathways.     

中国五种高山锄足蟾的核型、Ag-NORs和C-带的研究

作者用核型、Ag-NORs和C-带,对分布于川、滇两省的二属(齿突蟾、齿蟾)五种(胸腺齿突蟾、圆疣齿突蟾、凉北齿蟾、秉志齿蟾、疣刺齿蟾)锄足蟾作了属间和种间关系的比较分析,并讨论了它们的核型演化机制。结果表明:(1)齿突蟾和齿蟾两属间在核型和带型上都有明显的差异,演化途径主要的可能是含有重复DNA染色体片段的相互易位或臂间倒位;(2)属内不同种之间带型无显著差异,但某些对应染色体对间,其相对长度和臂比值差异明显,十分可能是常染色质片段的易位和臂间倒位所致;(3)凉北齿蟾有染色体数目变异多态现象;(4)五种锄足蟾均未发现异形性染色体。     

The effect of particle characteristics on the beam attenuation coefficient and output from an optical backscatter sensor

Experiments were conducted to measure optical backscatter and beam transmission of suspensions of 180, 150 and 90 μm sand, and 40 μm clay, in a recirculation tank designed to house an optical backscatterance sensor (O.B.S.) and a beam transmissometer. Particle size was determined using gravimetric techniques and Coulter counter. By contriving known sediment distributions from the fractionated sediment samples, it was found that both the O.B.S. and beam transmissometer responded approximately linearly to narrow band and broad band particle suspensions. The beam transmissometer showed greater sensitivity to the fine-grain fraction of a poly-disperse suspension than the O.B.S.     

Ecomorphological comparisons of sagittae in Mullus barbatus and M. surmuletus

For both Mullus barbatus and M. surmuletus , the relationship between sagitta area (O), sulcus acusticus area (S) throughout postlarval growth was characterized by their negative allometric growth. The adjusted mean S: O ratio differed between the two species. This may be associated with the difference in size and shape of the sagittae, a difference in somatic growth, and differences in food and spatial niches. The inner ear of Mullus cannot be considered as specialized and the interaction of stimuli detected by the sensory barbels and the inner ear together could be a compensatory mechanism that helps in the food search.     

Characterization of a novel non-muscle myosin-related protein from Onchocerca gibsoni

A cDNA library was constructed in λgt11 using poly(A)⁺ mRNA from early larvae of Onchocerca gibsoni. Screening of the library using serum from a single onchocerciasis patient yielded several strongly immunoreactive clones, one of which (OGK2) was found to encode a novel myosin-related protein. cDNA clone OGK2 contained an insert of 2017 bp, consisting of continuous open reading frame in frame with the vector; hence this clone encodes 671 amino acid residues of a larger protein. A fragment (619 nt) of the OGK2 cDNA was subcloned into the expression vector pGEX-1N to generate a glutathione S-transferase fusion protein. Polyclonal antiserum raised to this fusion protein strongly recognised an O. gibsoni protein of approximately 220 kDa. Immunolocalization studies indicated that this protein was associated predominantly with the hypodermis and a number of other specific membrane layers in the adult parasite. Myosin-related proteins are frequently immunodominant parasite antigens and in a number of studies have been shown to confer a degree of protective immunity against the corresponding parasite. Evaluation of the protective potential of the OGK2 protein, therefore, appears to be warranted.     

Variation in the loss of seed dormancy during after-ripening of wild and cultivated rice species

BACKGROUND AND AIMS: The aim of this paper was to verify the variation in the loss of seed dormancy during after-ripening and the interspecific and interpopulation variability in the degree of dormancy of seven wild and two cultivated rice species comprising 21 populations and two cultivars. METHODS: Four wild rice species from South America, Oryza glumaepatula, O. latifolia, O. grandiglumis and O. alta, and two O. sativa cultivars were tested in one experiment. In a second experiment, five wild species, O. punctata, O. eichingeri, O.rufipogon, O. latifolia and O. glumaepatula, and one cultivated species (O. glaberrima) were evaluated. Initial germination tests were performed soon after the seeds were harvested and subsequently at 2-month intervals, for a total of six storage periods in the first experiment and three in the second. All tests were conducted in the dark at a temperature of 27 degrees C. KEY RESULTS: Different patterns of after-ripening among populations within and between species were observed. CONCLUSIONS: The cultivated species (O. sativa and O. glaberrima) and, amongst the wild species, the tetraploids O. latifolia, O. grandiglumis and the diploids O. eichingeri and O. punctata, had weak dormancy, losing it completely 2 months after harvest, while O. rufipogon and O. glumaepatula exhibited pronounced dormancy. The latter showed different patterns of after-ripening between populations indigenous to the Amazon region and those originating in the Paraguay River system. Seeds of Solimoes (Amazon) and Japura origin showed weak dormancy whereas those of Paraguay origin showed deep dormancy. Ecological differences among natural habitats may be involved in such differentiation.     

棘豆属分类学新资料

作者同意赵一之先生关于海拉尔棘豆Ｏ。ｈａｉｌａｒｅｎｓｉｓ Ｋｉｔａｇ。这是尖叶棘豆Ｏ。ｏｘｐｈｙｌｌａ ＤＣ的观点,但提出其变种光果尖叶棘豆的变种名应是Ｏ。ｏｘｙｐｈｙｌｌａ ＤＣ。ｖａｒ。ｐｓｉｌｏｃａｒｐａ Ｇ．Ｚ．Ｑｉａｎ。     

Efficiency of Simulium sanctipauli as a vector of Onchocerca volvulus in the forest zone of Ghana

The role of Simulium sanctipauli Vajime & Dunbar (Diptera: Simuliidae) as a vector of Onchocerca volvulus (Leuckart) (Spirurida: Onchocercidae) in the forest zone of central Ghana was studied in the Upper Denkyira district, where onchocerciasis is hyperendemic. Simulium sanctipauli was found to be a highly efficient vector, with a mean of 377 infective (L3) larvae in the heads of 1000 parous and 122 in the heads of 1000 biting flies. The overall infection rate of 44% of the parous flies with L1, L2 and L3 stages of O. volvulus (identity confirmed by polymerase chain reaction) demonstrates marked anthropophily. Female flies dispersed over a wide area and can transmit onchocerciasis up to at least 10 km away from their breeding sites. Annual community-directed treatments with ivermectin did not have a noticeable effect on the infection rates and parasitic loads of fly populations, which were as high 2 months after as 3 months before the distribution of ivermectin. This failure can be attributed to poor coverage, with treatment taken by only 24.4% of the population of the six study villages.     

中国菝葜属补充与订正

本文涉及百合科菝葜属Smilax 7个分类群：用Smilax longibracteolata J.D.Hook.和S.elegans Wall.ex Kunth分别代替中国植物志第15卷(1978)中由于鉴定错误而使用的〖WTBX〗S.ma ireiH.Lévl.和S.glaucophylla Klotz.S.mairei是一个完全不同的种,应予承认,现根据存于爱丁堡的模式标本予以重新描述。S.pinfae nsis H.Lévl.和nthaC.H.Wright 在中国植物志第15卷中被分别并入S.cocculoides Warb.和S.ferox Wall.ex Kunth,现恢复为独立的种。此外,本文还发表了一个新改级〖WTBX〗S.retroflexa[WTBZ] (Wang et Tang ) S.C.Chen和一个新名称S.munita S.C.Chen,后者用来代替晚出同名S.rigida Wall.ex Kunth。     

中国景天属一些种的订正

本文对国产景天属的6种植物进行了分类订正。归并了7种1亚种和2变种,同时对中国植物志中景天属存疑种Sedum phyllanthum Levl.et Vant.和S.subtile Miq.的范围及其分类地位进行了讨论。根据对S.hsinganicum Chu ex S.H.Fu的模式标本以及S.floriferum Praeger模式标本图和模式产地标本的研究,确认二者所具性状均在S.aizoon L.的性状变异范围内,故予归并。S.onychopetalumFrod.,S.grammophyllum Frod以及S.anhuiense S.H.Fu et X.W.Wang经研究均被作为S.lineareThunb.的异名处理。S.formosanum N.E.Br.在《中国植物志》中被并入S.alfredii Hance,现恢复为独立的种。此外还报道了一个中国新记录种S.hakonense Makino。     

五种线虫生殖锥的形态研究

在光镜和扫描电镜玻地似血矛线虫,捻转血予线虫,辐射食道口线虫,粗纹食道口线虫,哥伦比亚食道一虫的生殖进行观察比较。结果表明：似血矛线虫的生殖锥的生殖附器只有一对乳突,而捻转血矛线虫的生殖附器有２对乳突。     

Interactions between beta-ecdysone and fat body during wing disk development in vitro

We have investigated the actions of beta-ecdysone and fat body on wing disks of Plodia interpunctella in a series of sequential incubations in vitro. These experiments revealed that extended treatment times of beta-ecdysone at concentrations of 0·5 μg/ml or greater inhibited development of disks, and confirm that the presence of a fat body factor in the culture medium prevents this inhibition.     

Development of a multiplex PCR for the identification of Staphylococcus genus and four staphylococcal species isolated from food

AIMS: To develop a multiplex PCR that allows the identification of bacteria belonging to the Staphylococcus genus and in particular to the species Staphylococcus xylosus, S. saprophyticus, S. epidermidis and S. aureus isolated from food manufacturing plants. METHODS AND RESULTS: Five primer pairs were used in the multiplex PCR, one specific to the Staphylococcus genus and four specific to S. xylosus, S. saprophyticus, S. epidermidis and S. aureus species. All the 31 Staphylococcus reference strains yielded a specific PCR product with the genus-specific primers. Staphylococcus xylosus, S. saprophyticus, S. epidermidis and S. aureus gave a specific PCR fragment with the corresponding species-specific primers. No amplification with the Kocuria, Macrococcus and Micrococcus strains was observed in our conditions. This multiplex PCR was performed on 30 strains of Gram-positive cocci isolated from different workshops and fermented sausages. Among them, 28 belonged to the Staphylococcus genus and 14 were identified to S. saprophyticus, four to S. xylosus, two to S. aureus and one to S. epidermidis. CONCLUSIONS: This multiplex PCR provided reliable and repeatable PCR results. It allowed the identification of a major part of the isolates, highlighting the predominance of the S. saprophyticus species in the workshops studied. SIGNIFICANCE AND IMPACT OF THE STUDY: This tool is a useful way to screen the strains isolated from foodstuff and food environment and to monitor these species during the food processing.     

Isolation of Onchocerca gibsoni tissue from frozen nodules for biochemical use

A new procedure is described which enables gram quantities of adult Onchocerca tissue to be isolated from frozen connective tissue nodules, thus minimizing the risk of enzymatic degradation. Bovine connective tissue nodules containing adult Onchocerca gibsoni worms were obtained from Australia frozen at −70°C and sectioned while still frozen into 3 mm thick slabs. The sections were thawed immediately before use, worm segments removed, rinsed, pelleted, and flash frozen in liquid nitrogen. Quality of the isolated material was demonstrated by the presence of an intact adult epicuticle as determined by electron microscopy, and by the presence of viable uterine larvae and cells. This procedure is applicable to other nodule-forming worms such as Onchocerca volvulus and is suitable for investigations which require the isolation of labile molecules or those present in minute quantities.