This study focuses on the determination of selenium and iodine in human thyroids. The glands were digested using nitric acid in a microwave oven. Selenium was determined by inductively coupled plasma optical emission spectrometry (ICP-OES) using a new sample introduction system consisting of a reduction system coupled to a hydride generation nebulizer (DHGN). Iodine was determined by using the Sandell-Kolthoff procedure. The detections limits were 0.2 ng/mL and 0.3 ng/mL for the determination method of selenium and iodine, respectively. The amount of iodine in the whole gland was 3.44 +/- 1.11 microg/g. The lowest iodine level was 2.34 microg/g and the highest 5.21 microg/g. The lowest selenium concentration for a single sample was 505 +/- 51 ng/g and the highest 1495 +/- 204 ng/g depending on the fraction of the gland selected. 相似文献
Plant breeding activities shape the rhizosphere microbiome but less is known about the relationship of both with the seed microbiome. We analyzed the composition of bacterial communities of seeds and rhizospheres of Styrian oil pumpkin genotypes in comparison to bulk soil to elucidate specific microbial signatures to support a concept involving plant-microbe interactions in breeding strategies.
Methods
The seed and rhizosphere microbiomes of 14 genotypes of oilseed pumpkin and relatives were analyzed using a 16S rRNA gene amplicon sequencing approach, which was assessed by bioinformatics and statistical methods.
Results
All analyzed microhabitats were characterized by diverse bacterial communities, but the relative proportions of phyla and the overall diversity was different. Seed microbiomes were characterized by the lowest diversity and dominant members of Enterobacteriaceae including potential pathogens (Erwinia, Pectobacterium). Potential plant-beneficial bacteria like Lysobacter, Paenibacillus and Lactococcus contributed to the microbial communities in significant abundances. Interestingly, strong genotype-specific microbiomes were detected for seeds but not for the rhizospheres.
Conclusions
Our study indicates a strong impact of the Cucurbita pepo genotype on the composition of the seed microbiome. This should be considered in breeding of new cultivars that are more capable of exploiting beneficial indigenous microbial communities.
Procyonidae were the first northern placental carnivorans that reached the Neotropics. They are represented by two extinct genera: ?Cyonasua and ?Chapalmalania (late Miocene – early Pleistocene). Postcranial elements are only known for ?Cyonasua and related taxa (?Parahyaenodon argentinus and ?Tetraprothomo argentinus). To obtain highly reliable allometric equations for body mass estimations of fossil procyonids, we performed least squares regressions (multiple and bivariate lineal models) using 51 postcranial linear measurements. The extant sample included 124 taxa corresponding to nine families of Carnivora, with body mass data from the literature. We obtained about 63 equations from diverse combinations of postcranial measurements; 14 of them were selected using several reliability indexes as criteria. Our results show that body masses calculated for ?Cyonasua range between 12.63 and 28.45 kg, ?P. argentinus was estimated at 14.41 kg, while ?T. argentinus at 25.31 kg. Thus, the body mass of ?Cyonasua would have been at least twice as high as the mean of the extant procyonid Procyon cancrivorus. ?Cyonasua was probably able to fend off predators and quite capable of climbing slowly on thick-enough branches. Other palaeoecological and palaeobiological inferences are discussed. 相似文献
Proteases able to unhair sheep skins were produced from Bacillus subtilis. Protease activity was increased from 640 to 990 U/mL by using a fed-batch culture with glucose added sequentially up to 10 g/L. The crude enzyme prep-aration was mainly a mixture of metallo- and serine-proteases with optimal pH and temperature for protease activity at 7 and 50-55°C, respectively. At pH 8 and 30°C, protease activity of the crude enzyme was 33% of the maximal value and 97% of the original activity (900 U/mL) was retained after incubation for 4 hours. 相似文献
The factors that control lichen distribution in Antarctica are still not well understood, and in this investigation we focused on the distribution, local and continental, and gas exchange of a species pair, closely related lichens with differing reproductive strategies, Usnea aurantiaco-atra (fertile) and Usnea antarctica (sterile, sorediate). The local distributions of these species were recorded along an altitudinal gradient of nearly 300 m at South Bay, Livingston Island, and microclimate was also recorded over 1 year. The photosynthetic responses to temperature, light and thallus water content were determined under controlled conditions in the laboratory. The species were almost identical in their photosynthetic profiles. Locally, on Livingston Island, U. antarctica was confined to low altitude sites which were warmer and drier, whilst U. aurantiaco-atra was present at all altitudes. This contrasts with its distribution across Antarctica where U. antarctica grows 9° latitude further south than U. aurantiaco-atra. Temperature appears not to be the main controller of distribution in these species, but dryness of habitat, which will influence length of activity periods, may be important. 相似文献
Abstract : In this work, it is shown that the Ca2+-transport ATPase found in the microsomal fraction of the cerebellum can use both glucose 6-phosphate/hexokinase and fructose 1,6-bisphosphate/phosphofructokinase as ATP-regenerating systems. The vesicles derived from the cerebellum were able to accumulate Ca2+ in a medium containing ADP when either glucose 6-phosphate and hexokinase or fructose 1,6-bisphosphate and phosphofructokinase were added to the medium. There was no Ca2+ uptake if one of these components was omitted from the medium. The transport of Ca2+ was associated with the cleavage of sugar phosphate. The maximal amount of Ca2+ accumulated by the vesicles with the fructose 1,6-bisphosphate system was larger than that measured either with glucose 6-phosphate or with a low ATP concentration and phosphoenolpyruvate/pyruvate kinase. The Ca2+ uptake supported by glucose 6-phosphate was inhibited by glucose, but not by fructose 6-phosphate. In contrast, the Ca2+ uptake supported by fructose 1,6-bisphosphate was inhibited by fructose 6-phosphate, but not by glucose. Thapsigargin, a specific SERCA inhibitor, impaired the transport of Ca2+ sustained by either glucose 6-phosphate or fructose 1,6-bisphosphate. It is proposed that the use of glucose 6-phosphate and fructose 1,6-bisphosphate as an ATP-regenerating system by the cerebellum Ca2+-ATPase may represent a salvage route used at early stages of ischemia ; this could be used to energize the Ca2+ transport, avoiding the deleterious effects derived from the cellular acidosis promoted by lactic acid. 相似文献
RCD1 is a member of the plant-specific SRO protein family. Several SRO genes have been functionally identified in the regulation of abiotic stresses in Arabidopsis and other plant species. However, the function of SROs is largely unknown in apple (Malus×domestica). In this study, six MdSRO-encoding genes were isolated, categorized into two types and mapped to six chromosomes. The phylogenetic analysis demonstrated that the sequences of the AtSRO and MdSRO proteins are highly conserved. Subsequently, expression analysis showed that MdSRO genes had different expression profiles in different tissues and in response to various stresses. Finally, MdRCD1 was isolated for functional identification. The results showed that resistance to oxidation stress in apple calli was enhanced by MdRCD1 overexpression and weakened by MdRCD1 suppression. MdRCD1 also played a crucial role in the regulation of ROS homeostasis in transgenic apple calli and Arabidopsis. Ectopic expression of MdRCD1 significantly enhanced resistance to salt and oxidative stresses in transgenic lines. In addition, MdRCD1 also enhanced drought tolerance due to its influence on stomatal opening. Based on these results, we conclude that MdRCD1 is an important regulator in abiotic stress response.
Light chain-associated amyloidosis is a fatal disease characterized by the aggregation and pathologic deposition of monoclonal light chain-related fragments as amyloid fibrils in organs or tissues throughout the body. Notably, it has been observed that proteins encoded by the lambda variable light chain (V(L)) gene segment 6a are invariably associated with amyloid deposition; however, the contribution of the gene to this phenomenon has not been established. In this regard, we have determined the thermodynamic stability and kinetics of in vitro fibrillogenesis of a recombinant (r) V(L) protein, designated 6aJL2, which contains the predicted sequences encoded by the 6a and JL2 germline genes. Additionally, we studied a 6a mutant (6aJL2-Arg25Gly), that is present in approximately 25% of all amyloid-associated lambda6 light chains. Remarkably, the wild-type 6aJL2 protein was more stable than were all known amyloidogenic kappa and lambda light chains for which stability parameters are available; more importantly, it was even more so (and less fibrillogenic) than the only clinically proven nonamyloidogenic lambda6 protein, Jto. Conversely, the mutated 6aJL2-R25G molecule was considerably less stable and more fibrillogenic than was the native 6aJL2. Our data indicate that the propensity of lambda6 light chains to form amyloid can not be attributed to thermodynamic instability of the germline-encoded Vlambda6 domain, but rather, is dependent on sequence alterations that render such proteins amyloidogenic. 相似文献