The colour pattern of the caudal fin, a useful criterion for identification of two species of Tilapia and their hybrids

The present work reports on some chromatic characters and their change with size in two species of Tilapia ( T. zillii and T. guineensis ) and their first generation hybrids. Successful reciprocal hybridizations between T. zillii and T. guineensis were performed in concrete tanks. The hybrids obtained were viable. The colour patterns of the hybrids and their parents were registered during a rearing cycle of 12 months. Between 2 and 13 cm standard length ( L _S), the hybrids were found to be heterogeneous and three phenotypes were observed. The type (1) phenotype had a fully yellowish caudal fin without dots, the type (2) phenotype had a bicoloured caudal fin with the upper part clear yellowish and the lower part dark yellowish and without dots and the type (3) had a similar bicoloured caudal fin, but with dots. Above 13 cm L _S, the hybrid population was homogenous and all specimens had a bicoloured caudal fin with dots. In T. zillii , all specimens >14 cm L _S had a greyish caudal fin with dots while all T. guineensis >13 cm L _S were characterized by a bicoloured caudal fin without dots. A multivariate analysis of the morphometric and meristic characters did not allow a clear separation of all groups. The study showed that the external morphology of the hybrids was intermediate to that of the parental species.     

Telomere elongation upon transfer to callus culture reflects the reprogramming of telomere stability control in Arabidopsis

Key message

Standard pathways involved in the regulation of telomere stability do not contribute to gradual telomere elongation observed in the course of A. thaliana calli propagation.

Abstract

Genetic and epigenetic changes accompanying the culturing of plant cells have frequently been reported. Here we aimed to characterize the telomere homeostasis during long term callus propagation. While in Arabidopsis thaliana calli gradual telomere elongation was observed, telomeres were stable in Nicotiana tabacum and N. sylvestris cultures. Telomere elongation during callus propagation is thus not a general feature of plant cells. The long telomere phenotype in Arabidopsis calli was correlated neither with changes in telomerase activity nor with activation of alternative mechanisms of telomere elongation. The dynamics of telomere length changes was maintained in mutant calli with loss of function of important epigenetic modifiers but compromised in the presence of epigenetically active drug zebularine. To examine whether the cell culture-induced disruption of telomere homeostasis is associated with the modulated structure of chromosome ends, epigenetic properties of telomere chromatin were analysed. Albeit distinct changes in epigenetic modifications of telomere histones were observed, these were broadly stochastic. Our results show that contrary to animal cells, the structure and function of plant telomeres is not determined significantly by the epigenetic character of telomere chromatin. Set of differentially transcribed genes was identified in calli, but considering the known telomere- or telomerase-related functions of respective proteins, none of these changes per se was apparently related to the elongated telomere phenotype. Based on our data, we propose that the disruption in telomere homeostasis in Arabidopsis calli arises from the interplay of multiple factors, as a part of reprogramming of plant cells to long-term culture conditions.

     

Proteomic characterization and antifungal activity of potato tuber proteins isolated from starch production waste under different temperature regimes

Proteins were obtained from effluent of a starch manufacture by using different isolation temperatures (40, 60, 80, and 100 °C). The proteins, remaining in effluent after treatment of potato juice at 80 and 100 °C differed significantly in composition and in structural stability as well as in trypsin inhibitory and antifungal activities in comparison with the variants of 40 and 60 °C. The protein samples of 80 °C exhibited the highest antifungal activity and its average value of IC₅₀ against five strains of two Fusarium species was determined in average at 0.18 mg ml⁻¹. The 80 °C protein samples consisted predominantly of low-molecular proteins (7–17 kDa) identified as potato tuber protease inhibitors I and II. Predominantly, protease inhibitors II were identified for the protein samples obtained by 100 °C and here we identified 7 spots in comparison with 12 identified for the 80 °C samples. Samples of 40 and 60 °C with low antifungal activities represent high variability of detected and identified proteins. We identified various representatives of aspartic, cysteine, and serine protease inhibitors in both types of samples. These samples also contained Kunitz-type protease inhibitors that were not found in the 80 and 100 °C samples which documented thermal unstableness of Kunitz-type protease inhibitors. Functional stability at high temperatures and antifungal activity of isolated potato protease inhibitors I and II support the potential of this fraction usage in food, feed, pharmaceutical, or agricultural industry and offer new products for starch manufactures. At the same time, utilization of the stable protein fraction of waste deproteinized potato water promotes exploitation of potato starch production resources.

     

Ultrastructure of the thick ascending limb of Henle in the rat kidney

The thick ascending limb of Henle (TAL) in the rat until recently has been considered a morphologically homogeneous structure despite physiologic and biochemical evidence to the contrary. The present study was designed to examine the ultrastructural characteristics of the TAL in the inner cortex and the outer and inner stripes of the outer medulla using qualitative and quantitative transmission electron microscopy. Kidneys of male Sprague-Dawley rats were preserved by in vivo perfusion with glutaraldehyde for light and electron microscopy. The peritubular diameter and cell height were determined by direct measurements on tubule cross sections. Morphometric analyses were performed on montages of tubule cross sections. The peritubular diameter of the TAL was similar in the three regions under investigation, but the TAL cells were taller in the inner stripe than in the inner cortex and outer stripe. Morphometry revealed significant differences between the three regions with respect to the mean tubular cross-sectional area (AT), the surface density (SV), and the surface area per mm of tubule (ST) of apical and basolateral plasma membranes, and the volume density (VV) of mitochondria. The major morphologic division appeared to be between the inner stripe segment and the remainder of the TAL. These findings document the presence of significant morphologic heterogeneity of the rat TAL.     

New allergies after cord blood transplantation

Background aimsUmbilical cord blood transplantation (CBT) is an effective treatment for benign and malignant diseases. Late effects of CBT are not well described in the literature. In the present study, we present our experience of new-onset allergies in long-term survivors after CBT.MethodsAfter an initial patient had a severe peanut allergic reaction after CBT, all CBT patients were prospectively followed for new allergy development. Fifty patients received CBT between March 2006 and June 2011.ResultsThe median follow-up after CBT was 447 days (range, 12–2022). At the time of analysis, 30 patients were alive, with 3-year survival of 55.5%; median follow-up of surviving patients was 910 days (range, 68–2022). The allergic syndrome developed in five patients, with the cumulative incidence of new allergies at 2 years of 18.4% (95% confidence interval, 10.8–26). The median time to onset of new allergy after transplantation was 298 days (range, 250–809).ConclusionsAllergy development has been linked to a delayed maturation of the immune system in several studies. We present the first case series of patients who had new allergies after CBT. Further study of this novel complication as well as counseling of patients after CBT would be important.     

Sulfadoxine-pyrimethamine impairs Plasmodium falciparum gametocyte infectivity and Anopheles mosquito survival

Sulfadoxine-pyrimethamine (SP) is currently the drug of choice for intermittent preventive treatment of Plasmodiumfalciparum both in pregnancy and infancy. A prolonged parasite clearance time conferred by dhfr and dhps mutations is believed to be responsible for increased gametocyte prevalence in SP treated individuals. However, using a direct feeding assay in Mali, we showed that gametocytes present in peripheral venous blood post-SP treatment had reduced infectivity for Anophelesgambiae sensu stricto (ss) mosquitoes. We investigated the potential mechanisms involved in the dhfr and dhps quintuple mutant NF-135 and the single dhps 437 mutant NF-54. Concentrations of sulfadoxine (S) and pyrimethamine (P) equivalent to the serum levels of the respective drugs on day 3 (S = 61 μg/ml, P = 154.7 ng/ml) day 7 (S = 33.8 μg/ml, P = 66.6 ng/ml) and day 14 (S = 14.2 μg/ml, P = 15.7 ng/ml) post-SP treatment were used to study the effect on gametocytogenesis, gametocyte maturation and infectivity to Anophelesstephensi mosquitoes fed through an artificial membrane. The drugs readily induced gametocytogenesis in the mutant NF-135 strain but effectively killed the wild-type NF-54. However, both drugs impaired gametocyte maturation yielding odd-shaped non-exflagellating mature gametocytes. The concomitant ingestion of both S and P together with gametocytemic blood-meal significantly reduced the prevalence of oocyst positivity as well as oocyst density when compared to controls (P < 0.001). In addition, day 3 concentrations of SP decreased mosquito survival by up to 65% (P < 0.001). This study demonstrates that SP is deleterious in vitro for gametocyte infectivity as well as mosquito survival.     

A molecular map of chloroquine resistance in Mali

Plasmodium falciparum chloroquine resistance (CQR) transporter point mutation (PfCRT 76T) is known to be the key determinant of CQR. Molecular detection of PfCRT 76T in field samples may be used for the surveillance of CQR in malaria-endemic countries. The genotype-resistance index (GRI), which is obtained as the ratio of the prevalence of PfCRT 76T to the incidence of CQR in a clinical trial, was proposed as a simple and practical molecular-based addition to the tools currently available for monitoring CQR in the field. In order to validate the GRI model across populations, time, and resistance patterns, we compiled data from the literature and generated new data from 12 sites across Mali. We found a mean PfCRT 76T mutation prevalence of 84.5% (range 60.9–95.1%) across all sites. CQR rates predicted from the GRI model were extrapolated onto a map of Mali to show the patterns of resistance throughout the participating regions. We present a comprehensive map of CQR in Mali, which strongly supports recent changes in drug policy away from chloroquine.     

Host reactions in Biomphalaria glabrata to Schistosoma mansoni miracidia, involving variations in parasite strains, numbers and sequence of exposures

M-line Biomphalaria glabrata snails are susceptible to Puerto Rican (PR-1) strain of Schistosoma mansoni, but are resistant to a St. Lucian (LC-1) strain. 10-R2 B. glabrata snails are resistant to both strains of S. mansoni. When 10-R2 snails were exposed repeatedly to PR-1 S. mansoni miracidia for 5 consecutive days, all of the sporocysts were encapsulated and destroyed by the snails. Thirty-four per cent of sporocysts examined in M-line snails with similar exposures were also degraded. In double concurrent infections of M-line B. glabrata with [³H]leucine-labeled and unlabeled PR-1 and Lc-1 S. mansoni, the incompatible Lc-1 miracidia were selectively attacked and destroyed. This destruction occurred irrespective of the sequence of exposure of the 2 strains of miracidia, and whether or not the miracidia were labeled. Successful superinfection of M-line B. glabrata with homologous S. mansoni miracidia was obtained at least 4 days after the primary exposure to the miracidia.