A mutation present in the amino terminus of Sabin 3 poliovirus VP1 protein is attenuating.

The attenuated phenotype of Sabin 3 poliovirus compared with its neurovirulent progenitor strain has been largely accounted for by mutations in the genome at positions 472 and 2034 (G. D. Westrop, K. A. Wareham, D. M. A. Evans, G. Dunn, P. D. Minor, D. I. Magrath, F. Taffs, S. Marsden, M. A. Skinner, G. C. Schild, and J. W. Almond, J. Virol. 63:1338-1344, 1989). By sequencing vaccine virus RNA, we recently identified another Sabin 3-specific mutation at position 2493 (U----C), which predicts an Ile----Thr change at the sixth residue of VP1 (C. Weeks-Levy, J. M. Tatem, S. J. DiMichele, W. Waterfield, A. F. Georgiu, and S. J. Mento, Virology 185:934-937, 1991). Viruses generated by using cDNAs which represent the vaccine sequence (LED3) and a derivative (VR318) possessing a single base change to the wild-type nucleotide (U) at 2493 were used to determine the impact of the 2493 mutation on virus phenotype. The VP1 proteins of LED3 and VR318 viruses were distinguishable by denaturing electrophoretic analysis. LED3 produced smaller plaques in Vero cells than VR318 virus did. Neurovirulence testing of these cDNA-derived viruses in monkeys demonstrated that the 2493 mutation in LED3 virus is attenuating.     

Effect of Cerebellar Lesions on Monoamine Levels in Various Brain Areas of the Cat

Abstract: Modifications in the content of monoamines after different lesions of the cerebellar cortex were investigated in eight prosencephalic structures of cat's brain. Apart from other minor changes, lesions of the posterior vermis induced significant changes in the thalamus (decrease of DA and increase of 5-HT). Lesions of the cortex of a cerebellar hemisphere, on the other hand, produced an increase of 5-HT in the caudate nucleus and an increase of DA in the hippocampus in addition to a generalized increase of 5-HT in all the prosencephalic structures studied. These findings are discussed in relation to the anatomical connections of the lesioned areas and their expected role in the sleep-wakefulness cycle.     

A phytosociological survey of some serpentine plant communities in the Dominican Republic

This paper presents a floristic and vegetation study of the serpentinised territories of the Dominican Republic, corresponding to the Yamasá and Prieta mountains, Dajabón, Puerto Plata and Gaspar Henández. These sites are very important at a local level as they act as speciation centres and have a specific ultramafic flora with a high endemicity rate. The floristic analysis revealed the existence of 219 species, of which 54 (24.7%) are endemic. Twenty-one plots of vegetation distributed in five areas dominated by serpentines have been analysed in this study. The phytosociological approach is based on the Braun-Blanquet method. The study was combined with statistical techniques such as multivariate analyses. The results revealed three different kinds of forests, one dominated by the endemic Bignoniaceae, Tabebuia berterii (CC.) Britton, which is peculiar to the subhumid–humid environments of the Caribbean-Cibensean territory. The second type of forest is dominated by the serpentinophyte Polygonaceae, Leptogonum buchii Urb. which thrives in the humid ombrotype of the north territory. Finally, the third one adopts the form of the pine forest of Dajabón, dominated by Pinus occidentalis Sw. Four associations and three alliances are proposed as new syntaxa based on statistical and phytosociological analyses.     

Leishmania amazonensis Promastigotes Present Two Distinct Modes of Nucleus and Kinetoplast Segregation during Cell Cycle

Here, we show the morphological events associated with organelle segregation and their timing in the cell cycle of a reference strain of Leishmania (L.) amazonensis promastigotes, the main causative agent of Tegumentary leishmaniasis in the Americas. We show evidences that during the cell cycle, L. amazonensis promastigotes present two distinct modes of nucleus and kinetoplast segregation, which occur in different temporal order in different proportions of cells. We used DAPI-staining and EdU-labeling to monitor the segregation of DNA-containing organelles and DNA replication in wild-type parasites. The emergence of a new flagellum was observed using a specific monoclonal antibody. The results show that L. amazonensis cell cycle division is peculiar, with 65% of the dividing cells duplicating the kinetoplast before the nucleus, and the remaining 35% doing the opposite or duplicating both organelles concomitantly. In both cases, the new flagellum appeared during S to G2 phase in 1N1K cells and thus before the segregation of both DNA-containing organelles; however, we could not determine the exact timing of flagellar synthesis. Most of these results were confirmed by the synchronization of parasites using hydroxyurea. Altogether, our data show that during the cell cycle of L. amazonensis promastigotes, similarly to L. donovani, the segregation of nucleus and kinetoplast do not follow a specific order, especially when compared to other trypanosomatids, reinforcing the idea that this characteristic seems to be species-specific and may represent differences in cellular biology among members of the Leishmania genus.     

Influence of carbon and nitrogen sources on lipase production by a newly isolated Candida viswanathii strain

Microorganisms can produce lipases with different biochemical characteristics making necessary the screening of new lipase-producing strains for different industrial applications. In this study, 90 microbial strains were screened as potential lipase producers using a sensitive agar plate method with a suitable medium supplemented with Tween 20 and also a liquid culture supplemented with olive oil. The highest cell growth and lipase production for Candida viswanathii were observed in triolein and oleic acid when used as the only pure carbon source. Renewable low-cost triacylglycerols supported the best cell growth, and olive oil was found to be the best inducer for lipase production (19.50 g/L and 58.50 U). The selected conditions for enzyme production were found with yeast extract as nitrogen source and 1.5 % (w/v) olive oil (85.70 U) that resulted in a good cell growth yield (Y_X/S?=?1.234 g/g) and lipase productivity (1.204 U/h) after 72 h of shake-flask cultivation. C. viswanathii lipase presented high hydrolytic activity on esters bonds of triacylglycerols of long-chain, and this strain can be considered an important candidate for future applications in chemical industries.     

Tasa estimada de disposición de glucosa en pacientes menores de 18 años con diabetes mellitus tipo 1 y sobrepeso-obesidad

ObjectiveTo assess the estimated glucose disposal rate (eGDR), insulin dose, and lipoprotein profile in children with type 1 diabetes mellitus (T1DM) and overweight or obesity as compared to children with T1DM and normal weight.MethodsA total of 115 patients (aged 5-16 years) with T1DM on intensive insulin therapy were recruited. The following parameters were measured: weight, height, body mass index, waist and hip circumference, insulin dose, eGDR, glycosylated hemoglobin, blood pressure, and lipoprotein profile. Results were stratified by sex and age.ResultsNo significant differences were found in eGDR between children with normal weight, overweight, and obesity. However, obese children older than 11 years had lower eGDR values (9.3 ± 1.3 vs 10.1 ± 0.8 mg kg^-1min^-1; p < 0.01). Insulin dose was higher in overweight and obese children, especially in IU/m²/day (37.7 vs 36.1 vs 29.4 respectively; p < 0.01). Obese children had higher low-density lipoprotein cholesterol levels than children with overweight and normal weight (106.5 vs 91.7 vs 91.5 mg/dL respectively; p < 0.01). No correlation was found between waist circumference and the different markers of insulin resistance.ConclusionsValues of eGDR values were lower in obese children with T1DM older than 11 years, and this may therefore be considered a marker of insulin resistance. Insulin dose was higher in diabetic patients with overweight or obesity, specially in IU/m²/day. Obese children with T1DM had a lipoprotein profile of cardiovascular risk.     

QTL‐seq: rapid mapping of quantitative trait loci in rice by whole genome resequencing of DNA from two bulked populations

The majority of agronomically important crop traits are quantitative, meaning that they are controlled by multiple genes each with a small effect (quantitative trait loci, QTLs). Mapping and isolation of QTLs is important for efficient crop breeding by marker‐assisted selection (MAS) and for a better understanding of the molecular mechanisms underlying the traits. However, since it requires the development and selection of DNA markers for linkage analysis, QTL analysis has been time‐consuming and labor‐intensive. Here we report the rapid identification of plant QTLs by whole‐genome resequencing of DNAs from two populations each composed of 20–50 individuals showing extreme opposite trait values for a given phenotype in a segregating progeny. We propose to name this approach QTL‐seq as applied to plant species. We applied QTL‐seq to rice recombinant inbred lines and F₂ populations and successfully identified QTLs for important agronomic traits, such as partial resistance to the fungal rice blast disease and seedling vigor. Simulation study showed that QTL‐seq is able to detect QTLs over wide ranges of experimental variables, and the method can be generally applied in population genomics studies to rapidly identify genomic regions that underwent artificial or natural selective sweeps.