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91.
92.
The responses of cellular C and N, pigments and growth rates of Alexandrium tamarense to different sources of N at high concentrations (6, 12, 25, 50 and 100 μM-N) were examined. Nitrate induced the highest concentration of cellular C (an indicator of biovolume) and cellular N, followed by ammonium and then urea. Cellular C to N ratio (an indicator of physiological status) also varied between N sources. Nitrate grown cells had lower range of C:N ratios and ammonium grown cells had highly variable range. Urea cultures had the highest range of cellular C:N ratio. Pigment composition remained unchanged with all N substrates. The pigments decreased with increasing nitrate concentrations, but with ammonium pigments increased. On the other hand, urea concentrations had no clear relationship with cellular pigments. Variability in the growth of cells was due to both the physiological condition and pigments. When the cells are exposed to different N environments and concentration, they exhibit a physiological acclimation by regulating their cellular materials which is associated with growth. 相似文献
93.
Graeme R Guy Permeen Yusoff DhinothKumar Bangarusamy Chee Wai Fong Esther Sook Miin Wong 《Cellular signalling》2002,14(1):11-20
The family of docker proteins containing phosphotyrosine-binding (PTB) domains appears to represent a family of critically positioned and exquisitely controlled signalling proteins that relay signals from the activated receptors to downstream pathways. These proteins all have a membrane attachment domain, a PTB domain that targets the protein to a subset of receptors and a number of phosphorylatable tyrosines that dock other signalling proteins. Evidence is accruing that suggests that the PTB domain has evolved from a pleckstrin homology (PH) domain to bind to a range of sequences that, while bestowing specificity, allows switching of the docker protein between receptors or signalling systems. The history of the PTB domain and how it influences the participation of docker protein in various signalling pathways are discussed. 相似文献
94.
Azemi Nur Farah Hani Misnan Rosmilah Keong Bun Poh Mokhtar Marina Kamaruddin Nurhaida Fah Wong Chee Yadzir Zailatul Hani Mohamad Yadzir Hani Mohamad Bakhtiar Faizal Abdullah Noormalin Arip Masita Ateshan Haidr Msahir 《Molecular biology reports》2021,48(10):6709-6718
Molecular Biology Reports - Tropomyosin is a major allergen in crustaceans, including mud crab species, but its molecular and allergenic properties in Scylla olivacea are not well known. Thus, this... 相似文献
95.
The digestive tract of Hoplosternum thoracatum consists of an esophagus, gastric area, anterior digestive intestine with elaborate folds, digestive intestine with decreasing folds and thin, smooth-surfaced respiratory intestine. The upper tract has a mucoid columnar lining which is gently folded, whereas the gastric area has numerous pits opening into the tubular secretory glands. Striated muscle comprises the anterior muscularis but is replaced by inner circular and outer longitudinal smooth muscle layers in the gastric region. The digestive intestinal mucosa is elaborately folded, consisting of columnar cells with prominent brush borders. Mucosa, submucosa, circular and longitudinal muscularis and serosa layers are present throughout the tract. Goblet cells occur in both the digestive and respiratory intestine. Major changes that appear in the respiratory intestine are a drastic reduction in mucosa epithelial thickness and the penetration of an elaborate capillary bed into the epithelium. The other basic layers are not significantly reduced in thickness. The air-blood barrier consists of the thin epithelium, basement lamina and very thin capillary endothelium. Regional cellular composition and ultrastructural features are correlated with respective digestive and respiratory functions. 相似文献
96.
Josephine Herbst Annabel Girke Mohammad Reza Hajirezaei Guy Hanke Bernhard Grimm 《The Plant journal : for cell and molecular biology》2018,94(3):485-496
Chlorophyll is synthesized from activated glutamate in the tetrapyrrole biosynthesis pathway through at least 20 different enzymatic reactions. Among these, the MgProto monomethylester (MgProtoME) cyclase catalyzes the formation of a fifth isocyclic ring to tetrapyrroles to form protochlorophyllide. The enzyme consists of two proteins. The CHL27 protein is proposed to be the catalytic component, while LCAA/YCF54 likely acts as a scaffolding factor. In comparison to other reactions of chlorophyll biosynthesis, this enzymatic step lacks clear elucidation and it is hardly understood, how electrons are delivered for the NADPH‐dependent cyclization reaction. The present study intends to elucidate more precisely the role of LCAA/YCF54. Transgenic Arabidopsis lines with inactivated and overexpressed YCF54 reveal the mutual stability of YCF54 and CHL27. Among the YCF54‐interacting proteins, the plastidal ferredoxin‐NADPH reductase (FNR) was identified. We showed in N. tabacum and A. thaliana that a deficit of FNR1 or YCF54 caused MgProtoME accumulation, the substrate of the cyclase, and destabilization of the cyclase subunits. It is proposed that FNR serves as a potential donor for electrons required in the cyclase reaction and connects chlorophyll synthesis with photosynthetic activity. 相似文献
97.
正Dear Editor,Zika virus(ZIKV),a pathogen within the genus Flavivirus,family Flaviviridae brought an international public health emergency due to its association with neonatal microcephaly case(Platt and Miner 2017).Currently the most reliable diagnostic test is PCR detection of ZIKV RNA from body fluid samples.Unfortunately,the short viremia window and asymptomatic/mild infections greatly reduce the success rate of PCRs(de Vasconcelos et al.2018). 相似文献
98.
S H Battah C E Chee H Nakanishi S Gerscher A J MacRobert C Edwards 《Bioconjugate chemistry》2001,12(6):980-988
Using a convergent growth approach, a series of novel 5-aminolevulinic acid (ALA)-containing dendrimers have been synthesized. In these molecules, ALA residues are attached to the periphery by ester linkages, with amide bonds connecting the dendrons. Three first-generation dendrimers, bearing either 6 or 9 ALA residues, were synthesized by attachment of a tris(Boc-protected ALA)-containing wedge (1) to a di- or tripodent aromatic, or tripodent aliphatic core. Two second generation 18-ALA-containing dendrimers were also synthesized using a 3,3'-iminodipropionic acid spacer unit between wedge 1 and the aromatic core. These compounds differed only in the distance between the core and the linker unit. The Boc-protected dendrimers were deprotected using trifluoroacetic acid and isolated as their TFA salts. The potential of these ALA ester dendrimers as macromolecular prodrugs for photodynamic therapy has been demonstrated in the tumorigenic keratinocyte PAM 212 cell line. 相似文献
99.
Yi Zhun Zhu Zhong Jing Wang Peiying Ho Yoke Yun Loke Yi Chun Zhu Shan Hong Huang Chee Sin Tan Matt Whiteman Jia Lu Philip K Moore 《Journal of applied physiology》2007,102(1):261-268
The role of hydrogen sulfide (H(2)S) in myocardial infarction (MI) has not been previously studied. We therefore investigated the effect of H(2)S in a rat model of MI in vivo. Animals were randomly divided into three groups (n = 80) and received either vehicle, 14 micromol/kg of sodium hydrosulfide (NaHS), or 50 mg/kg propargylglycine (PAG) everyday for 1 wk before surgery, and the treatment was continued for a further 2 days after MI when the animals were killed. The mortality was 35% in vehicle-treated, 40% in PAG-treated, and 27.5% in NaHS-treated (P < 0.05 vs. vehicle) groups. Infarct size was 52.9 +/- 3.5% in vehicle-treated, 62.9 +/- 7.6% in PAG-treated, and 43.4 +/- 2.8% in NaHS-treated (P < 0.05 vs. vehicle) groups. Plasma H(2)S concentration was significantly increased after MI (59.2 +/- 7.16 microM) compared with the baseline concentration (i.e., 38.2 +/- 2.07 microM before MI; P < 0.05). Elevated plasma H(2)S after MI was abolished by treatment of animals with PAG (39.2 +/- 5.02 microM). We further showed for the first time cystathionine-gamma-lyase protein localization in the myocardium of the infarct area by using immunohistochemical staining. In the hypoxic vascular smooth muscle cells, we found that cell death was increased under the stimuli of hypoxia but that the increased cell death was attenuated by the pretreatment of NaHS (71 +/- 1.2% cell viability in hypoxic vehicle vs. 95 +/- 2.3% in nonhypoxic control; P < 0.05). In conclusion, endogenous H(2)S was cardioprotective in the rat model of MI. PAG reduced endogenous H(2)S production after MI by inhibiting cystathionine-gamma-lyase. The results suggest that H(2)S might provide a novel approach to the treatment of MI. 相似文献
100.
Competitive inhibition of binding between radioiodine-labelled encephalitogenic basic protein from human myelin (125I-HEProt) and normal human alpha-2 macroglobulin and between 125I-HEProt and rabbit antiHEProt serum was used to study concentrated cerebrospinal fluid (CSF) under “blind” control for cross-reactivity with HEProt. Samples of CSF from patients meeting the standard criteria for definite MS and possible MS, and from patients with optic neuritis and “other” diagnoses were studied. CSF from patients in all four groups was shown to have an inhibitor cross-reactive with HEProt when studied by the 125I-HEProt/alpha-2 macroglobulin test, but the amount was significantly greater in the definite MS group than in the “other” group. Results of the two tests on CSF from MS patients correlated, suggesting that the tests were identifying the same inhibitor. It was concluded that CSF contains an inhibitor similar to HEProt and that the amount present in CSF could be a useful diagnostic marker of MS. 相似文献