Spatio-temporal distribution patterns of Chironomidae communities in the wadis of Northern Tunisia / Padrões de distribuição espaço-temporal de comunidades Chironomidae nos wadis do norte da Tunísia

In Northern Tunisia, seasonal streams, called wadi, are characterized by extreme hydrological and thermal conditions. These freshwater systems have very particular features as a result of their strong irregularity of flow due to limited precipitation runoff regime, leading to strong seasonal hydrologic fluctuations. The current study focused on the spatio-temporal distribution of chironomids in 28 sampling sites spread across the Northern Tunisia. By emplying PERMANOVA, the results indicated a significant spatio-temporal variation along various environmental gradients. The main abiotic factors responsible for noted differences in the spatial distribution of chironomids in wadi were the conductivity and temperature, closely followed by altitude, pH, salinity, talweg slope and dissolved oxygen, identified as such by employing distance-based linear models' procedure. The Distance-based redundancy analysis ordination showed two main groups: the first clustered the Bizerte sites, which were characterized by high water conductivity, sodium concentration and salinity. The second main group comprised sites from the Tell zone and was characterized by low temperatures, neutral pH, low conductivity and nutrients content. The subfamily TANYPODIINAE (e.g., Prochladius sp., Prochladius choerus (Meigen, 1804) and Macropelopia sp.) was the dominant group at Tell zone, whereas species such as Diamesa starmachi (Kownacki et Kownacha, 1970) and Potthastia gaedii (Meigen, 1838) were found only in Tell Wadis. In contrast, chironomid species such as Diamesa starmachi (Kownacki et Kownacha, 1970), Potthastia gaedii (Meigen, 1838), Procladius choreus (Meigen, 1804) were specific for Tell Mountain. Cap Bon wadis region was dominated by genus Cladotanytarsus sp. The results of this survey liked the taxonomic composition of chironomid assemblages to the variation of hydromorphological and physic-chemical gradients across the northern Tunisia wadis.

No norte da Tunísia, riachos sazonais chamados wadi são caracterizados por condições hidrológicas e térmicas extremas. Esses sistemas de água doce têm características muito particulares como resultado de sua forte irregularidade de fluxo devido ao regime de escoamento de precipitação limitado, levando a fortes flutuações hidrológicas sazonais. O estudo atual enfocou a distribuição espaço-temporal dos quironomídeos em 28 locais de amostragem espalhados pelo norte da Tunísia. Ao aplicar PERMANOVA, os resultados indicaram uma variação espaço-temporal significativa ao longo de vários gradientes ambientais. Os principais fatores abióticos responsáveis pelas diferenças observadas na distribuição espacial dos quironomídeos no wadi foram a condutividade e a temperatura, seguidos de perto por altitude, pH, salinidade, declive do talvegue e oxigênio dissolvido, identificados como tais empregando o procedimento de modelos lineares baseados na distância. A ordenação da análise de redundância baseada em distância mostrou dois grupos principais: o primeiro agrupou os sítios Bizerte, que foram caracterizados por alta condutividade da água, concentração de sódio e salinidade. O segundo grupo principal compreendia locais da zona de Tell e era caracterizado por baixas temperaturas, pH neutro, baixa condutividade e conteúdo de nutrientes. A subfamília Tanypodiinae (por exemplo, Prochladius sp., Prochladius choerus [Meigen, 1804] e Macropelopia sp.) era o grupo dominante na zona de Tell, enquanto espécies como Diamesa starmachi (Kownacki et Kownacha, 1970) e Potthastia gaedii (Meigen, 1838) foram encontradas apenas em Tell Wadis. Em contraste, espécies de quironomídeos, como Diamesa starmachi (Kownacki et Kownacha, 1970), Potthastia gaedii (Meigen, 1838), Procladius choreus (Meigen, 1804), eram específicas para Tell Mountain. A região de Cap Bon wadis [...].

Manipulation of a quasi-natural cell block for high-efficiency transplantation of adherent somatic cells

Recent advances have raised hope that transplantation of adherent somatic cells could provide dramatic new therapies for various diseases. However, current methods for transplanting adherent somatic cells are not efficient enough for therapeutic applications. Here, we report the development of a novel method to generate quasi-natural cell blocks for high-efficiency transplantation of adherent somatic cells. The blocks were created by providing a unique environment in which cultured cells generated their own extracellular matrix. Initially, stromal cells isolated from mice were expanded in vitro in liquid cell culture medium followed by transferring the cells into a hydrogel shell. After incubation for 1 day with mechanical agitation, the encapsulated cell mass was perforated with a thin needle and then incubated for an additional 6 days to form a quasi-natural cell block. Allograft transplantation of the cell block into C57BL/6 mice resulted in perfect adaptation of the allograft and complete integration into the tissue of the recipient. This method could be widely applied for repairing damaged cells or tissues, stem cell transplantation, ex vivo gene therapy, or plastic surgery.