A Simple Method for Isolating DNA of High Yield and Quality from Cotton (shape Gossypium hirsutum L.) Leaves

An easy, reproducible and fast procedure to isolate DNA from cotton leaves is described. The addition of 0.5 M glucose in the extraction buffer avoids browning by polyphenolic compounds and improves the quality of DNA for molecular analysis. The DNA yield ranged between 150–400 mg per gram of fresh tissue. The DNA was suitable for digestion by restriction enzymes and amplificatiion by Taq DNA polymerase.     

A mechanobiological model to study upstream cell migration guided by tensotaxis

Biomechanics and Modeling in Mechanobiology - Cell migration is a process of crucial importance for the human body. It is responsible for important processes such as wound healing and tumor...     

Cryptic speciation in the field vole: a multilocus approach confirms three highly divergent lineages in Eurasia

Species are generally described from morphological features, but there is growing recognition of sister forms that show substantial genetic differentiation without obvious morphological variation and may therefore be considered ‘cryptic species’. Here, we investigate the field vole (Microtus agrestis), a Eurasian mammal with little apparent morphological differentiation but which, on the basis of previous sex‐linked nuclear and mitochondrial DNA (mtDNA) analyses, is subdivided into a Northern and a Southern lineage, sufficiently divergent that they may represent two cryptic species. These earlier studies also provided limited evidence for two major mtDNA lineages within Iberia. In our present study, we extend these findings through a multilocus approach. We sampled 163 individuals from 46 localities, mainly in Iberia, and sequenced seven loci, maternally, paternally and biparentally inherited. Our results show that the mtDNA lineage identified in Portugal is indeed a distinct third lineage on the basis of other markers as well. In fact, multilocus coalescent‐based methods clearly support three separate evolutionary units that may represent cryptic species: Northern, Southern and Portuguese. Divergence among these units was inferred to have occurred during the last glacial period; the Portuguese lineage split occurred first (estimated at c. 70 000 bp ), and the Northern and Southern lineages separated at around the last glacial maximum (estimated at c. 18 500 bp ). Such recent formation of evolutionary units that might be considered species has repercussions in terms of understanding evolutionary processes and the diversity of small mammals in a European context.     

Euclein: A new binaphthaquinone from Euclea pseudebenus

7-MethyljugIone, 8,8′-dihydroxy-4,4′-dimethoxy-6,6′-dimethyl-2,2′-binaphthyl-1,1′-quinone, 2-methylnaphthazarin, mamegakinone and euclein have been isolated from Euclea pseudebenus. Euclein is the 3,6′-dimer of 7-methyljuglone.     

Evolutionary relationships among hares from North Africa (Lepus sp. or Lepus spp.), cape hares (L. capensis) from South Africa, and brown hares (L. europaeus), as inferred from mtDNA PCR-RFLP and allozyme data

Systematics and taxonomy of hares of the genus Lepus (Lagomorpha) are under contentious debate, and phylogenetic relationships among many taxa are not well understood. Here we study genetic differentiation and evolutionary relationships among North African hares, currently considered subspecies of Lepus capensis , cape hares ( L. capensis ) from the Cape province in South Africa, and brown hares ( L. europeaus ) from Europe and Anatolia, using maternally (mtDNA) and biparentally (allozymes) inherited markers. A polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis of a c. 1.8 kb long segment of the mitochondrial control region using eight hexanucleotide-recognizing restriction endonucleases yielded 28 haplotypes, and horizontal starch gel electrophoresis of proteins encoded by 25 structural gene loci revealed 52 alleles at 18 polymorphic loci. Diverse phylogenetic analyses (neighbor joining dendrogram, median joining network, multidimensional scaling of pairwise distances, AMOVA, F -statistics, hierarchical F -statistics) of genetic variants revealed marked substructuring of mtDNA into three phylogeographic groups, namely an African, a central European, and an Anatolian, but a somewhat less pronounced overall differentiation of the nuclear genome, despite a relatively high number of population-specific (private) alleles. However, all our results are not incongruent with Petter's (1959: Mammalia 23 , 41; 1961: Z. f. Säugetierkunde 26 , 30; 1972 : Société Des Sciences Naturelles et Physiques du Maroc 52 , 122) hypothesis that North African hares generally belong to L. capensis and that brown hares should be included in this species as well.     

Production of trace levels of carbon monoxide during methanogenesis on acetate and methanol

Summary Production of trace levels of carbon monoxide was consistently observed in the off-gas of a laboratory anaerobic digester fed Waste Activated Sludge. Inocula from this digester was enriched for acetate and methanol utilizing methanogenic populations. These enriched inocula were then monitored in batch assays for carbon monoxide and hydrogen production. Results demonstrated that carbon monoxide is produced during methanogenesis on both substrates. Subsequent utilization of CO was observed to occur after methane production was essentially complete for the assays conducted with methanol. Carbon monoxide evolution during methanogenesis on acetate displayed a markedly different trend from that observed from methanol.     

Effects of arsenate on the Ca2+ ATPase of sarcoplasmic reticulum

The effect of arsenate on the partial reactions of the catalytic cycle of the Ca2+ ATPase of skeletal muscle of sarcoplasmic reticulum was studied. With the use of native vesicles it was found that arsenate accelerates the rate of ITP hydrolysis and inhibits both Ca2+ or Sr2+ uptake. These effects were not observed when ATP was used as substrate or, with the use of ITP, when leaky vesicles were assayed. Activation of ITP hydrolysis is related to an increase of the enzyme's apparent affinity for ITP. Arsenate increases the steady-state level of the phosphoenzyme formed from ITP. This depends on the concentration of both Pi and Ca2+, in the medium. Ca2+ and Sr2+ efflux were accelerated by arsenate. The fast Ca2+ efflux promoted by arsenate is impaired by external Ca2+. Arsenate competes with Pi for the phosphorylating site of the enzyme.     

Observations on the lungworm, Pneumostrongylus calcaratus, in impala (Aepyceros melampus) from Swaziland

The lungworm, Pneumostrongylus calcaratus, was found in 85% (164 of 193) of impala (Aepyceros melampus) collected in Mlawula Nature Reserve in Swaziland. Infection was confirmed at 4.5 mo of age, and the prevalence increased to 100% at 11 mo, with a prevalence of 98% in animals greater than 1 yr of age. Pneumostrongylus calcaratus was usually found in firm, tangrey nodules along the lobar borders of the lungs, although an extensive granulomatous pneumonia with miliary caseous abscesses and calcified nodules was observed in some older animals. In the primary infection in lambs, adult parasites, larvae and eggs were observed in the alveoli and bronchioles within the nodule. There was peribronchial and perivascular mononuclear cuffing, with infiltration of mononuclear cells in the alveolar septum in the vicinity of worms. In lesions in older animals, there was local consolidation with macrophages and giant cells, and foci of parenchymal necrosis associated with degenerating eosinophils, which appeared to lead to the formation of eosinophilic granulomas. Resolving lesions caused interstitial fibrosis, with mineralized nodules. Pneumostrongylosis does not appear to pose a significant threat to the health of impala in Swaziland.     

Production of Poly-β-Hydroxyalkanoic Acid by Pseudomonas cepacia

The possibility of using the nutritionally versatile bacterium Pseudomonas cepacia to produce poly-β-hydroxyalkanoic acid was evaluated. Chemostat culture showed that growth of P. cepacia became nitrogen limited when the molar carbon-to-nitrogen ratio of the medium fed into the fermentor was above 15. When grown under nitrogen limitation in batch culture with fructose as the sole source of carbon, P. cepacia accumulated poly-β-hydroxybutyric acid (PHB) in excess of 50% of the dry weight of its biomass. In batch culture, almost no PHB was produced until the onset of nitrogen limitation. After this point, PHB was produced at a linear rate of 0.12 g liter⁻¹ h⁻¹ (from a constant value of 1.6 g of cellular protein liter⁻¹). PHB produced by P. cepacia had a weight-average molecular weight of 5.37 × 10⁵ g mol⁻¹ and a polydispersivity index of 3.9. Poly(β-hydroxybutyric acid-β-hydroxyvaleric acid) copolymer was produced with a poly-β-hydroxybutyric acid-poly-β-hydroxyvaleric acid ratio of up to 30% by weight when propionic acid was added to the medium.