124 research outputs found
Pollen of Ceratostema (Ericaceae, Vaccinieae) : tetrads without septa
Get PDFThe pollen morphology of two species of the Neotropical genus Ceratostema (Ericaceae) was examined by light, scanning and transmission electron microscopy. The Ceratostema species examined have 3-colporate pollen grains united in permanent tetrahedral tetrads that show a common condition encountered in the Ericaceae. But the septal exine was absent between two neighboring grains in each pollen tetrad of Ceratostema. The pollen tetrads without septa are the first report for the Ericaceae as well as other angiosperm families
Short- and long-term adaptation to ethanol stress and its cross-protective consequences in Lactobacillus plantarum
Get PDFThis paper describes the molecular responses of Lactobacillus plantarum WCFS1 toward ethanol exposure. Global transcriptome profiling using DNA microarrays demonstrated adaptation of the microorganism to the presence of 8% ethanol over short (10-min and 30-min) and long (24-h) time intervals. A total of 57 genes were differentially expressed at all time points. Expression levels of an additional 859 and 873 genes were modulated after 30 min and 24 h of exposure to the solvent, respectively. Ethanol exposure led to induced expression of genes involved in citrate metabolism and cell envelope architecture, as well as canonical stress response pathways controlled by the central stress regulators HrcA and CtsR. Correspondingly, cells grown for 24 h in medium containing 8% ethanol exhibited higher levels of citrate consumption and modified cell membrane fatty acid composition and showed invaginating septa compared with cells grown in liquid medium without ethanol. In addition, these physiological changes resulted in cross-protection against high temperatures but not against several other stresses tested. To evaluate the role of HrcA and CtsR in ethanol tolerance, ctsR and hrcA gene deletion mutants were constructed. The growth rate of the L. plantarum ¿ctsR::cat strain was impaired in de Man-Rogosa-Sharpe (MRS) medium containing 8% ethanol, whereas growth of the L. plantarum ¿hrcA::cat and ¿ctsR ¿hrcA::cat mutants was indistinguishable from that of wild-type cells. Overall, these results suggest that the induction of CtsR class III stress responses provides cross-protection against heat stress
Switching from a Unicellular to Multicellular Organization in an Aspergillus niger Hypha
No full textPores in fungal septa enable cytoplasmic streaming between hyphae and their compartments. Consequently, the mycelium can be considered unicellular. However, we show here that Woronin bodies close ~50% of the three most apical septa of growing hyphae of Aspergillus niger. The incidence of closure of the 9th and 10th septa was even ?94%. Intercompartmental streaming of photoactivatable green fluorescent protein (PA-GFP) was not observed when the septa were closed, but open septa acted as a barrier, reducing the mobility rate of PA-GFP ~500 times. This mobility rate decreased with increasing septal age and under stress conditions, likely reflecting a regulatory mechanism affecting septal pore diameter. Modeling revealed that such regulation offers effective control of compound concentration between compartments. Modeling also showed that the incidence of septal closure in A. niger had an even stronger impact on cytoplasmic continuity. Cytoplasm of hyphal compartments was shown not to be in physical contact when separated by more than 4 septa. Together, data show that apical compartments of growing hyphae behave unicellularly, while older compartments have a multicellular organization.BiotechnologyApplied Science
Immunolocalization of sclerostin synthesized by osteocytes in relation to bone remodeling in the interradicular septa of ovariectomized rats
Get PDFThis study aimed to elucidate whether estrogen deficiency would affect the synthesis of an osteocyte-derived factor, sclerostin, in the mesial region of alveolar bone. Eight 9-week-old Wistar female rats were ovariectomized (OVX) and the other eight rats were Sham-operated (Sham). After 4 weeks, the interradicular septa of mandibular first molar were embedded in paraffin, and then, were histochemically examined. Sclerostin-positive osteocytes were located in a superficial layer of the mesial region of Sham bone, while the OVX mesial region showed a lesser presence of the sclerostin-reactive osteocytes. There was no significant difference in the distribution of estrogen receptor α and TUNEL-positive cells in either Sham or OVX groups. Meanwhile, the Sham mesial region demonstrated many osteoclasts, but the OVX specimens showed numerous osteoclasts in association with intense immunolabeling of the receptor activator of the nuclear factor kB ligand. Complex meshwork of cement lines was seen consistent with irregularly-distributed osteocytic lacunar-canalicular system in the OVX mesial region, compared with those of the Sham specimens. In conclusion, estrogen deficiency appears to inhibit osteocytes for sclerostin synthesis in the mesial region of the interradicular septum, mediated by accelerated bone remodeling, rather than by directly effecting osteocytes
Hydropower Potential in Indonesia: Assessment of theoretical, technical and economic potential of hydropower
No full textIndonesia has a severe problem of fossil fuel dependency, making it become one the world’s larger carbon emission contributor. At the same time, the growing population will increase the energy demand in the future. Thus, in order to meet the energy demand and decrease the carbon emission, the government together with PLN as the state electricity company will committed to implement carbon neutral targets by 2060. Additional of 413 GW installed power capacity will be necessary in which 308 GW generated from renewable energy. Indonesia has many renewable energy alternatives that can be utilized such as solar, wind, biomass, and hydropower. Among various renewable energy alternatives, hydropower has emerged as one of the means to achieve the aforementioned targets. Indonesia has a hydropower potential of around 75 GW from large hydropower and 19.4 GW from small hydropower, meanwhile, due to a number of barriers, hydropower contributed only 7% from installed large-scale hydropower and 2% from installed small-scale power plants.In order to reach the government’s goals, further study is needed to better understand the hydropower potential in Indonesia. Hence, the aim of this research is to quantify the potential of hydropower for Indonesia to find the possible location based on the economic consideration and to understand the positive influence of hydropower application. The analyses will be done using GIS-based modelling approach based on three DEM sources with 3 different resolutions, namely DEMNAS (0.27 arcseconds), USGS (1 arcsecond) and MERIT (3 arcseconds). The gross theoretical potential will be calculated based on the river discharge and the head of every pixel of the DEM. Further, the technical potential could be obtained by eliminating the output of theoretical potential with contraints area. Subsequently, the cost components (e.g investment and operational cost) will be added to the model to quantify the levelized cost of electricity (LCOE). The potential location that has LCOE lower the cost of power generation.Based on the analysis, the theoretical potential in Indonesia ranges for approximately 159 GW to 182 GW, or in annual energy production amounts to 1400 TWh to 1600 TWh. Subsequently, the technical potential after eliminating the constraints area decreased to around 550 TWh (63 GW) – 700 TWh (80 GW). On the other hand, based on the technical potential results, the LCOE ranges from 1 to 69 cent USD/kWh. However, only around 45% of the total technical potential is economically feasible. Thus, the hydropower potential lowered to 240 TWh (10 GW) – 690 TWh (38 GW). According the results, hydropower could cover 9% to 25% of the total required additional capacity planned by PLN and could reduce the carbon emission around 90% compared to the carbon emission of fossil fuels. Since this study used three different DEM resolutions, the output of the analyses varies depending on the DEM used. Based on the results, higher resolution DEM could delineate river shape better and thus the location of estimated hydropower potential location could be more accurate. However, DEM with larger pixel size could detect better the medium and large hydropower potentialWater Managemen
Pleuropneumonia in swine associated with urease-negative variant of Actinobacillus pleuropneumoniae serotype 1
No full textA pig farm of 6000 weaning to market age pigs had a mortality rate of 2.8% in October 1989 and 1.9% in April 1990. Four pigs were examined PM. All pigs had pulmonary haemorrahage with patchy necrosis and fibrinous pleuritis which was seen, on histological examiantion, as severe haemorrhagic and necrotizing pleuropneumonia with extensive fibrin exudate into alveoli and interlobular septa. Gray stickly colonies of gram-negative pleomorphic rods were isolated from 1 or 2 sites on each pig. These were identified as urease negative variants of Actinobacillus pleuropneumoniae serotype 1
The Influence of Using Information Transfer Technique towards Students’ Reading Comprehension
Get PDFIn a process of teaching learning activity, teachers strive to create activities in class to make the students understand with the material that teachers give, when a book as a main source of knowledge in learning process, reading is an important process in teaching learning activity, many teachers try to apply technique to make students comprehend of what they read, and to make students interested in reading activity. In this paper the author introduces the technique known as information transfer. By first collecting different definitions of the term and then by explaining its application to English language teaching that can be used in teaching reading activity. Therefore, the present study was carried out to investigate the relationship between the use of information transfer and students’ reading comprehension, i.e. to determine whether or not making use of information transfer has any influence on the students’ reading comprehension. The methodology was true-experimental design with the treatment. The population of this research was the second semester of the tenth grade students of MAN I Metro, Lampung. The sample taken was two classes randomly, 1K2 (X-2) and 1K3 (X-3) which consisted of 64 students. In collecting the data, the writer used the instruments in multiple-choice questions of descriptive text. After being tried-out, the instrument was used for the pre-test and the post-test
- …
