Leptomonas lactosovorans n. sp., a Lactose-Utilizing Trypanosomatid: Description and Nutritional Requirements1

Leptomonas lactosovorans n. sp. is described from the gut of the reduviid hemipteran Zelurus martinsi. It can be grown in a defined medium. The requirements for amino acids, vitamins, purine, and heme were similar to those established for Crithida fasciculata. Growth is stimulated by aeration. Generation time is longer than for any other insect trypanosomatid described; its utilization of lactose as a carbon source is a unique feature among trypanosomatids.     

中国和越南苔类植物新记录种——柏氏细鳞苔

报道了采自中国广西和越南北部地区细鳞苔属新记录种——柏氏细鳞苔[Lejeunea patersonii(Steph.)Steph.]。该种的主要特征为侧叶顶端圆形或钝形,叶边缘具圆齿;腹叶小,远生,宽为茎的1~2倍;叶细胞角质层平滑,三角体不明显或中等大,中部球状加厚缺。该研究对柏氏细鳞苔与其相似种进行了细致的比较讨论,并对柏氏细鳞苔原有的地理分布信息进行了更正,重新确认了该种的地理分布。     

中国苦苣苔科一新记录属——四轮苣苔属

该文报道了中国苦苣苔科(Gesneriaceae)一新记录属——四轮苣苔属(Tetraphyllum Griff. ex C. B. Clarke)。该新记录属,即四轮苣苔属仅有3种,其中密花四轮苣苔[T. confertiflorum(Drake)B. L. Burtt]在我国首次记录。该研究提供了该属的形态描述和分种区别特征,并提供了该种的详细形态描述及彩色照片。凭证标本馆藏于广西植物研究所标本馆(IBK)和上海辰山植物标本馆(CSH)。     

Vertical transmission in feather mites: insights into its adaptive value

1. The consequences of symbiont transmission strategies are better understood than their adaptive causes. 2. Feather mites are permanent ectosymbionts of birds assumed to be transmitted mainly vertically from parents to offspring. The transmission of Proctophyllodes doleophyes Gaud (Astigmata, Proctophyllodidae) was studied in two European populations of pied flycatchers, Ficedula hypoleuca Pallas (Passeriformes, Muscicapidae). 3. The vertical transmission of this mite species is demonstrated here with an acaricide experiment. This study also compared (for two distant populations during 4 years) patterns in reductions in mite intensity in adult birds, from egg incubation to chick‐rearing periods, with the predictions of three hypotheses on how host survival prospects and mite intraspecific competition might drive feather mites' transmission strategy. 4. The results are in agreement with previous studies and show that feather mites transmit massively from parents to chicks. 5. The magnitude of the transmission was closer to that predicted by the hypothesis based on intraspecific competition, while a bet‐hedging strategy is also partially supported.     

Iridoids are natural glycation inhibitors

Glycation of amino acid residues in proteins leads to the eventual formation of advanced glycation end products (AGEs). AGE formation significantly influences human health and the aging process. AGE accumulation rates may be slowed by modifications to lifestyle or by pharmacological strategies. But the use of therapeutic drugs is not an appropriate means of controlling AGEs within the general population. However, phytochemical constituents in plant-based foods exhibit anti-glycation activities and may be more appropriate for general consumption. Among these phytochemicals are iridoids. The anti-AGE potential of iridoids has been demonstrated in vitro and in vivo, while also revealing possible mechanisms of action. Inclusion of iridoid food sources in the diet may be a useful component of strategies intended to mitigate AGE accumulation within the body.     

Mechanism of Acquired Immunity Induced by “Leptomonas pessoai” against Trypanosoma cruzi in Mice*

Living culture forms of “Leptomonas pessoai” cross protected mice against T. cruzi challenge infection. Circulating antibodies have been detected in the immunized mice by immunodiffusion analysis, passive hemagglutination, complement fixation test and antibody binding assay; these antibodies cross reacted with T. cruzi extracts. A cellular immune response was indicated by leucocyte migration inhibition using L. pessoai and T. cruzi antigens, strongly suggesting a role for cell-mediated immunity in the mechanism of protection induced by L. pessoai.     

Polymorphism of intron-1 in the voltage-gated sodium channel gene of Anopheles gambiae s.s. populations from Cameroon with emphasis on insecticide knockdown resistance mutations

Sequence variation at the intron-1 of the voltage-gated sodium channel gene in Anopheles gambiae M- and S-forms from Cameroon was assessed to explore the number of mutational events originating knockdown resistance ( kdr ) alleles. Mosquitoes were sampled between December 2005 and June 2006 from three geographical areas: (i) Magba in the western region; (ii) Loum, Tiko, Douala, Kribi, and Campo along the Atlantic coast; and (iii) Bertoua, in the eastern continental plateau. Both 1014S and 1014F kdr alleles were found in the S-form with overall frequencies of 14% and 42% respectively. Only the 1014F allele was found in the M-form at lower frequency (11%). Analysis of a 455 bp region of intron-1 upstream the kdr locus revealed four independent mutation events originating kdr alleles, here named MS1 -1014F, S1-1014S and S2-1014S kdr- intron-1 haplotypes in S-form and MS3-1014F kdr- intron-1 haplotype in the M-form. Furthermore, there was evidence for mutual introgression of kdr 1014F allele between the two molecular forms, MS1 and MS3 being widely shared by them. Although no M/S hybrid was observed in analysed samples, this wide distribution of haplotypes MS1 and MS3 suggests inter-form hybridizing at significant level and emphasizes the rapid diffusion of the kdr alleles in Africa. The mosaic of genetic events found in Cameroon is representative of the situation in the West–Central African region and highlights the importance of evaluating the spatial and temporal evolution of kdr alleles for a better management of insecticide resistance.