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991.
The Immunogenic Glycoprotein gp35-37 of Human Herpesvirus 8 Is Encoded by Open Reading Frame K8.1 总被引:6,自引:3,他引:6 下载免费PDF全文
Marc-Steffen Raab Jens-Christian Albrecht Alexander Birkmann Svenja Yaubolu Dieter Lang Bernhard Fleckenstein Frank Neipel 《Journal of virology》1998,72(8):6725-6731
Human herpesvirus 8 (HHV-8) is likely to be involved in the pathogenesis of Kaposi’s sarcoma (KS) and body cavity-based lymphomas (BCBLs). The HHV-8 genome is primarily in a latent state in BCBL-derived cell lines like BCBL-1, but lytic replication can be induced by phorbol esters (R. Renne, W. Zhang, B. Herndier, M. McGrath, N. Abbey, D. Kedes, and D. E. Ganem, Nat. Med. 2:342–346, 1996). A 35- to 37-kDa glycoprotein (gp35-37) is the polypeptide most frequently and intensively recognized by KS patient sera on Western blots with induced BCBL-1 cells. Its apparent molecular mass is reduced to 30 kDa by digestion with peptide-N-glycosidase F. By searching the known HHV-8 genomic sequence for open reading frames (ORF) with the potential to encode such a glycoprotein, an additional, HHV-8-specific reading frame was identified adjacently to ORF K8. This ORF, termed K8.1, was found to be transcribed primarily into a spliced mRNA encoding a glycoprotein of 228 amino acids. Recombinant K8.1 was regularly recognized by KS patient sera in Western blots, and immunoaffinity-purified antibodies to recombinant K8.1 reacted with gp35-37. This shows that the immunogenic gp35-37 is encoded by HHV-8 reading frame K8.1, which will be a useful tool for studies of HHV-8 epidemiology and pathogenesis. 相似文献
992.
Having been activated with glutaraldehyde, modified poly(ethylene terephthalate) grafted acrylamide fiber was used for the
immobilization of horseradish peroxidase (HRP). Both the free HRP and the immobilized HRP were characterized by determining
the activity profile as a function of pH, temperature, thermal stability, effect of organic solvent and storage stability.
The optimum pH values of the enzyme activity were found as 8 and 7 for the free HRP and the immobilized HRP respectively.
The temperature profile of the free HRP and the immobilized HRP revealed a similar behaviour, although the immobilized HRP
exhibited higher relative activity in the range from 50 to 60 °C. The immobilized HRP showed higher storage stability than
the free HRP. 相似文献
993.
对云南元江普通野生稻(O.rufipogon)90个个体Wx基因区段内的重复序列(CT)n和第一内含子供体+1位碱基G/T分别进行了比较分析。结果表明云南元江普通野生稻三个居群中的90个单株在重复序列(CT)n和G/T位点纯合一致,没有多态性;其G/T位点碱基均为G;其重复序列(CT)n基因型与云南地方籼稻品种优势基因型相似但又有所区别。本研究结果为云南元江普通野生稻Wx基因利用和在稻种进化上的地位提供了信息。 相似文献
994.
995.
Atika Meklat Salim Mokrane Abdelghani Zitouni Nadjette Djemouai Hans-Peter Klenk 《Geomicrobiology journal》2020,37(9):826-836
Abstract The Sahara, one of the most extreme environments on Earth, constitutes an unexplored source of alkalitolerant actinobacteria. In this work, we studied the diversity of alkalitolerant actinobacteria in various soils collected from different regions of the Algerian Sahara. A total of 29 alkalitolerant actinobacterial strains were isolated by using a complex agar medium. The diversity of these actinobacteria was evaluated using a polyphasic approach, which included morphological, chemotaxonomic, physiological (numerical taxonomy) and 16S rRNA gene analyses. The isolates which were assigned to the genus Nocardiopsis, shared relatively low 16S rRNA gene sequences similarities compared to closely related species suggesting that they belonged to putatively new species. All of the strains were tested for antibiotic activity against a broad range of microorganisms and screened for genes encoding polyketide synthases and non-ribosomal peptide synthetases and found to have the potential to produce secondary metabolites. Consequently, the study supports the view that extreme environments contain many novel actinobacteria, which represent an unexplored source for the discovery of biologically active compounds. 相似文献
996.
Cansın Özgör Seray Şenyer Özgör Adil Deniz Duru Ümmühan Işoğlu-Alkaç 《Cognitive neurodynamics》2018,12(4):357-363
Time perception is defined as a subjective judgment on the elapsed time of an event. It can change according to both external and internal factors. There are two main paradigms of time perception; retrospective time perception (RTP) and prospective time perception (PTP). Two paradigms differ from each other according to whether the subject has knowledge on the importance of passage of time in the given task. Since RTP paradigm studies are harder to conduct, studies on RTP paradigm is far fewer than studies on PTP. Thus in the current study, both RTP and PTP paradigms are investigated. Also, time perception is discussed in relation to internal clock model and cognitive load. Emotional motion videos are used to create cognitive load and manipulate internal clock. Results showed the effect of emotion on time perception. Another major finding is that shorter videos are perceived longer whereas longer videos are perceived shorter as in accordance with Vierordt’s Law. However, there was no difference between RTP and PTP paradigms. These results indicate that emotional videos change our internal clock while a number of changes in a motion video create cognitive load causing disturbance of time perception. 相似文献
997.
A strong cohort of evidence exists that supports the localisation of corneal stem cells at the limbus. The distinguishing characteristics of limbal cells as stem cells include slow cycling properties, high proliferative potential when required, clonogenicity, absence of differentiation marker expression coupled with positive expression of progenitor markers, multipotency, centripetal migration, requirement for a distinct niche environment and the ability of transplanted limbal cells to regenerate the entire corneal epithelium. The existence of limbal stem cells supports the prevailing theory of corneal homeostasis, known as the XYZ hypothesis where X represents proliferation and stratification of limbal basal cells, Y centripetal migration of basal cells and Z desquamation of superficial cells. To maintain the mass of cornea, the sum of X and Y must equal Z and very elegant cell tracking experiments provide strong evidence in support of this theory. However, several recent stud-ies have suggested the existence of oligopotent stem cells capable of corneal maintenance outside of the limbus. This review presents a summary of data which led to the current concepts of corneal epithelial homeostasis and discusses areas of controversy surrounding the existence of a secondary stem cell reservoir on the corneal surface 相似文献
998.
Arica MY Yalçin E Bayramoğlu G 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2004,807(2):315-325
In this study, an affinity membrane containing L-histidine as an amino acid ligand was used in separation and purification of human immunoglobulin G (HIgG) from solution and human serum. The polarities and the surface free energies of the affinity membranes were determined by contact angle measurements. HIgG adsorption and purification onto the affinity membranes from aqueous solution and human serum were investigated in a batch and a continuous system. Effect of different system parameters such as ligand density, adsorbent dosage, pH, temperature, ionic strength and HIgG initial concentration on HIgG adsorption were investigated. The maximum adsorption capacity of p(HEMA-MAAH-4) membranes for HIgG was 13.06 mgml(-1). The reversible HIgG adsorption on the affinity membrane obeyed both the Langmuir and Freundlich isotherm models. The adsorption data was analysed using the first- and second-order kinetic model and the experimental data was well described by the first-order equations. In the continuous system, the purity of the eluted HIgG, as determined by HPLC, was 93% with recovery 58% for p(HEMA-MAAH-4) membrane. The affinity membranes are stable when subjected to sanitization with sodium hydroxide after repeated adsorption-elution cycles. 相似文献
999.
One hallmark feature of consolidation of episodic memory is that only a fraction
of original information, which is usually in a more abstract form, is selected
for long-term memory storage. How does the brain perform these differential
memory consolidations? To investigate the neural network mechanism that governs
this selective consolidation process, we use a set of distinct fearful events to
study if and how hippocampal CA1 cells engage in selective memory encoding and
consolidation. We show that these distinct episodes activate a unique assembly
of CA1 episodic cells, or neural cliques, whose response-selectivity ranges from
general-to-specific features. A series of parametric analyses further reveal
that post-learning CA1 episodic pattern replays or reverberations are mostly
mediated by cells exhibiting event intensity-invariant responses, not by the
intensity-sensitive cells. More importantly, reactivation cross-correlations
displayed by intensity-invariant cells encoding general episodic features during
immediate post-learning period tend to be stronger than those displayed by
invariant cells encoding specific features. These differential reactivations
within the CA1 episodic cell populations can thus provide the hippocampus with a
selection mechanism to consolidate preferentially more generalized knowledge for
long-term memory storage. 相似文献
1000.
Ting Ting Xiao Gwendolyn K Kirschner Boubacar A Kountche Muhammad Jamil Maria Savina Vinicius Lube Victoria Mironova Salim al Babili Ikram Blilou 《Plant physiology》2022,189(4):2281
The parasitic plant Striga (Striga hermonthica) invades the host root through the formation of a haustorium and has detrimental impacts on cereal crops. The haustorium results from the prehaustorium, which is derived directly from the differentiation of the Striga radicle. The molecular mechanisms leading to radicle differentiation shortly after germination remain unclear. In this study, we determined the developmental programs that regulate terminal prehaustorium formation in S. hermonthica at cellular resolution. We showed that shortly after germination, cells in the root meristem undergo multiplanar divisions. During growth, the meristematic activity declines and associates with reduced expression of the stem cell regulator PLETHORA1 and the cell cycle genes CYCLINB1 and HISTONE H4. We also observed a basal localization of the PIN-FORMED (PIN) proteins and a decrease in auxin levels in the meristem. Using the structural layout of the root meristem and the polarity of outer-membrane PIN proteins, we constructed a mathematical model of auxin transport that explains the auxin distribution patterns observed during S. hermonthica root growth. Our results reveal a fundamental molecular and cellular framework governing the switch of S. hermonthica roots to form the invasive prehaustoria.The parasitic plant Striga hermonthica forms its invasive organ, the prehaustorium, by inducing differentiation of the radicle by arresting cell division. 相似文献