The mature mRNA always carries nucleotide sequences that faithfully mirror the protein product according to the rules of the genetic code. However, in the chromosome, the nucleotide sequence that represents a certain protein is interrupted by additional sequences. Therefore, most eukaryotic genes are longer than their final mRNA products. The human genome project revealed that only a tiny portion of sequences serves as protein-coding region and almost one quarter of the genome is occupied by non-coding intervening sequences. The elimination of these non-coding regions from the precursor RNA in a process termed splicing must be extremely precise, because even a single nucleotide mistake may cause a fatal error. At present, two types of intervening sequences have been identified in protein-coding genes. One of them, the U2-dependent or major-class is prevalent and represents 99% of known sequences. The other one, the so-called U12-dependent or minor-class of introns, occurs in much lesser amounts in the genome. The basic problem of nuclear splicing concerns i/ the molecular mechanisms, which ensure that the coding regions are correctly recognized and spliced together; ii/ the principles and mechanisms that guarantee the high fidelity of the splicing system; iii/ the differences in the excision mechanisms of the two classes of introns. We are going to present models explaining how intervening sequences are accurately removed and the coding regions correctly juxtaposed. The two splicing mechanisms will also be compared.
Temperature is a dominant factor in rice development. Various thermal time methods are a possible way to model the development, and are able to predict phenological stages such as flowering. In our studies three different bilinear models were studied concerning the predicting of duration from emergence to flowering of rice based on phenological data collected from rice experiments carried out in the Irrigation Research Institute between 1991 and 1999 with the rice variety Ringola. The advance from linear model, which is preferred in agriculture involves an upper threshold temperature as a second parameter, and describes the development rate with a constant (Method 1) and two different steepness functions of linear decrease (Method 2 and 3) above this threshold. The duration of the phenological phase showed only slight variations (coefficient of variation, CV=6.43), thus the average number of days offered an acceptable prediction. The linear method did not show a significant improvement (CV=3.96) on the level P=5%. However the three tested bilinear methods resulted in significant development (CV=2.75; 2.71 and 2.73) if adequate parameters were applied. The distribution of variation coefficients according to different parameter combinations gave information on sensitivity of methods, while the adequate parameters of lower and upper thresholds provided some hints about climatic demands of rice.
Authors:E. Bajmócy, Ibolya Turcsányi, G. Bölske, Á. Bacsadi and I. Kiss
The occurrence of a goat disease caused byMycoplasma mycoidessubsp.mycoidesLC in Hungary is reported. The disease occurred in two goat herds in the spring of 1999. In one herd 25% of the 4–12 weeks old kids (10 animals) while in the other herd 33% of the 6–12 weeks old kids (20 animals) became affected. The goat kids developed polyarthritis. The most severe lesions developed in the carpal joints. All animals died after 3–8 days of disease. Four dead kids were necropsied. All of them had serofibrinous and purulent polyarthritis, and in two animals bronchopneumonia, fibrinous pleuritis and meningitis were also found. In the articular exudates the presence of mycoplasmas was detected by PCR using a general mycoplasma primer. Mycoplasmas were cultured from the joints of all animals, from the abdominal parenchymal organs of two kids and from the lungs of one animal. The cultured mycoplasmas grew in strikingly large colonies, proved to be glucose positive, arginine negative and phosphatase positive, and liquefied the coagulated serum. They survived incubation at 45 °C for more than 24 h. Based upon their biochemical properties, the results of the immunofluorescence (IF) and growth inhibition tests and the sequence analysis of the PCR product, the cultured strains were identified asM. mycoidessubsp.mycoidesLC. Animals purchased in the previous autumn had been introduced to both farms. The disease may have been introduced with asymptomatic carrier animals, as earlier no similar disease had been observed at either farm.
Authors:Attila Szabó, Péter Igaz, Róbert Kiss, Gergely Lakatos, Ibolya Varga and Károly Rácz
A szerzők súlyos hypercortisolismussal, hypokalaemiával, diabetes mellitusszal és osteoporosissal járó ectopiás ACTH-szindrómás esetüket ismertetik. Az ACTH-elválasztó tumorszövet a tüdőben helyezkedett el, amelynek szegmentális eltávolítását követő szövettani vizsgálat ACTH-termelő neuroendokrin daganatot igazolt. Az első műtétet követően a plazmakortizol- és -ACTH-szintek nem csökkentek szignifikánsan, ennek hátterében a tumor szubtotális eltávolítása állt. Tartós hatású szomatosztatinanalóg-terápia bevezetését követően mind a kortizol-, mind az ACTH-szintek számottevően csökkentek, és a beteg általános állapota szignifikánsan javult. Reoperációt követően a beteg véglegesen meggyógyult és jelenleg is panasz- és tünetmentes. Orv. Hetil., 2011, 152, 403–406.