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71.
72.
Deletions of two of four DAZ (Deleted in AZoospermia) gene copies located on the Y chromosome were associated with spermatogenic failure, but the information on DAZ copy number is still very scarce. The aim of this study was to determine the frequency of partial DAZ gene deletions and to analyze the existence of duplications in general Slovenian and Bosnian population. To answer these questions, we used real time PCR. We analyzed 100 male samples from Slovenian and Bosnian general population. The incidence of two DAZ gene copies was 6% (3/50) in Slovenian population. The incidence of more than four DAZ genes was 2% (1/50) in Slovenian population and 8% (4/50) in Bosnian population. Observed differences have not reached statistical significance. In conclusion we demonstrate that DAZ genes are not only prone to deletions but also to duplication events. Further studies are needed to estimate the prevalence of these mutations and its' relevance to male infertility. 相似文献
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74.
Oliver T. Fackler Paola d''Aloja Andreas S. Baur Maurizio Federico B. Matija Peterlin 《Journal of virology》2001,75(14):6601-6608
Human immunodeficiency virus type 1(F12) (HIV-1(F12)) interferes with the replication of other strains of HIV. Its accessory protein, Nef, is sufficient for this phenotype, where the production and infectivity of HIV are impaired significantly. The analysis of three rare mutations in this Nef protein revealed that these effects could be separated genetically. Moreover, the defect in virus production correlated with the lack of processing of the p55(Gag) precursor in the presence of Nef from HIV-1(F12). Importantly, the introduction of one of these mutations (E177G) into Nef from HIV-1(NL4-3) also created a dominant-negative Nef protein. Effects of Nef from HIV-1(F12) on virus production and Gag processing correlated with its altered subcellular distribution. Moreover, the association with two new cellular proteins with molecular masses of 74 and 75 kDa, which do not interact with other Nef proteins, correlated with the decreased virion infectivity. The identification of a dominant-negative protein for the production and infectivity of HIV suggests that Nef plays an active role at this stage of the viral replicative cycle. 相似文献
75.
Krystyna?MusialEmail author Borut?Bohanec Marijana?Jak?e Leslaw?Przywara 《In vitro cellular & developmental biology. Plant》2005,41(4):446-452
Summary The development of embryo sacs (ES) in vitro and induction of gynogenesis were studied in onion flower bud culture. Explants were divided into three groups according
to their size at inoculation: (a) small flower buds (2.3–3.0 mm in diameter); (b) medium flower buds (3.1–3.7 mm); and (c)
large flower buds (3.8–4.4 mm). For histological study, excised ovaries were fixed at inoculation and then at 3-d intervals
until day 12, and after 2 and 3 wk of culture. Some explants were cultured until embryo emergence, i.e., 3–5 mo. In total,
2592 ovules were examined histologically. At inoculation, 83% of ovules in small flower buds contained a megaspore mother
cell; in 17% of ovules, two-nucleate ES occurred. In medium flower buds two-nucleate, four-nucleate, and mature ES were present
at frequencies of 15%, 46%, and 40%, respectively. In large flower buds, only mature ES occurred. In vitro conditions did not disturb meiosis and megagametophyte development in non-degenerated ovules. Regardless of the developmental
stage at inoculation, only mature ES occurred on day 12. Gynogenic embryos were found after 2 wk of culture, indicating that
embryos developed in mature ES exclusively. Embryos were detected in 5.4% of histological studied ovules; however, the number
of embryos after 3–5 mo. was higher (12.4%). The parthenogenetic origin of the embryos is discussed. In addition, ES containing
endosperm only (6.5%) and both endosperm and embryo (0.4%) were observed. 相似文献
76.
Fackler OT Lu X Frost JA Geyer M Jiang B Luo W Abo A Alberts AS Peterlin BM 《Molecular and cellular biology》2000,20(7):2619-2627
The activation of Nef-associated kinase (NAK) by Nef from human and simian immunodeficiency viruses is critical for efficient viral replication and pathogenesis. This induction occurs via the guanine nucleotide exchange factor Vav and the small GTPases Rac1 and Cdc42. In this study, we identified NAK as p21-activated kinase 1 (PAK1). PAK1 bound to Nef in vitro and in vivo. Moreover, the induction of cytoskeletal rearrangements such as the formation of trichopodia, the activation of Jun N-terminal kinase, and the increase of viral production were blocked by an inhibitory peptide that targets the kinase activity of PAK1 (PAK1 83-149). These results identify NAK as PAK1 and emphasize the central role its kinase activity plays in cytoskeletal rearrangements and cellular signaling by Nef. 相似文献
77.
Primo? Peterlin Vesna Arrigler Saša Svetina Peter Walde 《Chemistry and physics of lipids》2009,159(2):67-420
The interaction of two types of vesicle systems was investigated: micrometer-sized, giant unilamellar vesicles (GUVs) formed from 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and submicrometer-sized, large unilamellar vesicles (LUVs) formed from oleic acid and oleate, both in a buffered aqueous solution (pH 8.8). Individual POPC GUVs were transferred with a micropipette into a suspension of oleic acid/oleate LUVs, and the shape changes of the GUVs were monitored using optical microscopy. The behavior of POPC GUVs upon transfer into a 0.8 mM suspension of oleic acid, in which oleic acid/oleate forms vesicular bilayer structures, was qualitatively different from the behavior upon transfer into a 0.3 mM suspension of oleic acid/oleate, in which oleic acid/oleate is predominantly present in the form of monomers and possibly non-vesicular aggregates. In both cases, changes in vesicle morphology were observed within tens of seconds after the transfer. After an initial increase of the vesicle cross-section, the vesicle started to evaginate, spawning dozens of satellite vesicles connected to the mother vesicle with narrow necks or tethers. In 60% of the cases of transfer into a 0.8 mM oleic acid suspension, the evagination process reversed and proceeded to the point where the membrane formed invaginations. In some of these cases, several consecutive transitions between invaginated and evaginated shapes were observed. In the remaining 40% of the cases of transfer into the 0.8 mM oleic acid suspension and in all cases of vesicle transfer into the 0.3 mM oleic acid suspension, no invaginations nor subsequent evaginations were observed. An interpretation of the observed vesicle shape transformation on the basis of the bilayer-couple model is proposed, which takes into account uptake of oleic acid/oleate molecules by the POPC vesicles, oleic acid flip-flop processes and transient pore formation. 相似文献
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79.
Borut Fonda Andrej Panjan Goran Markovic Nejc SarabonAuthor vitae 《Journal of electromyography and kinesiology》2011,21(5):854-860
The main aim of this project was to study muscle activity patterns during steep uphill cycling (UC) (i.e., with a gradient of 20%) with (1) normal saddle geometry and (2) with adjusted saddle position ASP (i.e., moving the saddle forward and changing the tilt of the saddle by 20%). Based on our preliminary case study, we hypothesized that: (1) during 20% UC muscle activity patterns would be different from those of level cycling (LC) and (2) during 20% UC with ASP muscle activity patterns would resemble those of LC. Twelve trained male cyclists were tested on an electromagnetically braked cycle ergometer under three conditions with the same work rate (80% of maximal power output) and cadence (90 rpm): level (LC), 20% UC and 20% UC with ASP. Electromyographic signals were acquired from m. tibialis anterior (TA), m. soleus (SO), m. gastrocnemius (GC), m. vastus lateralis (VL), m. vastus medialis (VM), m. rectus femoris (RF), m. biceps femoris (BF) and m. gluteus maximus (GM). Compared to LC, 20% UC significantly modified both the timing and the intensity of activity of the selected muscles, while muscles that cross the hip joint were the most affected (RF later onset, earlier offset, shorter range of activity and decrease in peak amplitude of 34%; BF longer range of activity; GM increase in peak amplitude of 44%). These changes in EMG patterns during 20% UC were successfully counteracted by the use of ASP and it was interesting to observe that the use of ASP during 20% UC was perceived positively by all cyclists regarding both comfort and performance. These results could have a practical relevance in terms of improving performance during UC, together with reducing discomfort. 相似文献
80.
Tatjana Ćosić Branka Vinterhalter Dragan Vinterhalter Nevena Mitić Aleksandar Cingel Jelena Savić Borut Bohanec Slavica Ninković 《In vitro cellular & developmental biology. Plant》2013,49(3):294-303
A simple and efficient protocol for direct somatic embryogenesis and plant regeneration of kohlrabi (Brassica oleracea var. gongylodes) was developed. Somatic embryos were induced from immature zygotic embryos at different developmental stages cultured on Murashige and Skoog medium supplemented with 0, 0.5, 1.0, or 1.5 mg/l 2,4-dichlorophenoxyacetic acid. Zygotic embryos at the early cotyledonary stage, which were cultured for 4 wk on plant growth regulator-free (PGR-free) medium, displayed the highest percentage of somatic embryogenesis (80.7%). Embryogenic tissue could be subcultured on the same medium for over 1 yr. Embryogenic lines derived from early cotyledonary stage zygotic embryos displayed the highest intensity of secondary embryogenesis (highest mean number of new somatic embryos per responsive somatic embryo explant). Histological analyses confirmed the direct origin of the secondary somatic embryos. Prolonged culturing of embryogenic tissue on PGR-free medium led to somatic embryo development into plantlets that were successfully acclimated in the greenhouse with a survival rate of 72.5%. Flow cytometry analysis showed no ploidy variation in 96.7% of the acclimated plants. 相似文献