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71.
To determine the importance of fibroblast growth factor receptors (fgfrs) 1 and 2 in the metanephric mesenchyme, we generated conditional knockout mice (fgfr(Mes-/-)). Fgfr1(Mes-/-) and fgfr2(Mes-/-) mice develop normal-appearing kidneys. Deletion of both receptors (fgfr1/2(Mes-/-)) results in renal aplasia. Fgfr1/2(Mes-/-) mice develop a ureteric bud (and occasionally an ectopic bud) that does not elongate or branch, and the mice do not develop an obvious metanephric mesenchyme. By in situ hybridization, regions of mutant mesenchyme near the ureteric bud(s) express Eya1 and Six1, but not Six2, Sall1, or Pax2, while the ureteric bud expresses Ret and Pax2 normally. Abnormally high rates of apoptosis and relatively low rates of proliferation are present in mutant mesenchyme dorsal to the mutant ureteric bud at embryonic day (E) 10.5, while mutant ureteric bud tissues undergo high rates of apoptosis by E11.5. Thus, fgfr1 and fgfr2 together are critical for normal formation of metanephric mesenchyme. While the ureteric bud(s) initiates, it does not elongate or branch infgfr1/2(Mes-/-) mice. In metanephric mesenchymal rudiments, fgfr1 and fgfr2 appear to function downstream of Eya1 and Six1, but upstream of Six2, Sall1, and Pax2. Finally, this is the first example of renal aplasia in a conditional knockout model. 相似文献
72.
Deepali Gupta 《Inorganica chimica acta》2007,360(7):2379-2386
1-Methylisocytosine (1-MeIC) can be protonated at the endocyclic N(3) position (pKa of 1-MeICH+, 4.02 ± 0.04) or complexed at this position with (dien)MII (M = Pt, Pd). X-ray crystal structures of the protonated species 1 as well as the Pd (2) and Pt (3) complexes are reported, and gas phase structures of the cation 2 and 3 have been calculated by ab initio methods. These results are compared with results from X-ray crystallography. At high pH, the Pt complex 3 undergoes deamination of the exocyclic N(2)H2 group to the 1-methyluracilate complex. As compared to the situation with 1-methylcytosine (1-MeC), the accelerating effect of (dien)PtII is much less pronounced, however. 相似文献
73.
Dipannita Basu Yuxin Tian Jayant Bhandari Jian Ru Jiang Patricia Hui Rodney L. Johnson Ram K. Mishra 《PloS one》2013,8(8)
The activity of G protein-coupled receptors (GPCRs) is intricately regulated by a range of intracellular proteins, including G protein-coupled kinases (GRKs) and arrestins. Understanding the effects of ligands on these signaling pathways could provide insights into disease pathophysiologies and treatment. The dopamine D2 receptor is a GPCR strongly implicated in the pathophysiology of a range of neurological and neuropsychiatric disorders, particularly schizophrenia. Previous studies from our lab have shown the preclinical efficacy of a novel allosteric drug, 3(R)- [(2(S)-pyrrolidinylcarbonyl)amino]-2-oxo-1-pyrrolidineacetamide (PAOPA), in attenuating schizophrenia-like behavioural abnormalities in rodent models of the disease. As an allosteric modulator, PAOPA binds to a site on the D2 receptor, which is distinct from the endogenous ligand-binding site, in order to modulate the binding of the D2 receptor ligand, dopamine. The exact signaling pathways affected by this allosteric modulator are currently unknown. The objectives of this study were to decipher the in vivo effects, in rats, of chronic PAOPA administration on D2 receptor regulatory and downstream molecules, including GRK2, arrestin-3 and extracellular receptor kinase (ERK) 1/2. Additionally, an in vitro cellular model was also used to study PAOPA’s effects on D2 receptor internalization. Results from western immunoblots showed that chronic PAOPA treatment increased the striatal expression of GRK2 by 41%, arrestin-3 by 34%, phospho-ERK1 by 51% and phospho-ERK2 by 36%. Results also showed that the addition of PAOPA to agonist treatment in cells increased D2 receptor internalization by 33%. This study provides the foundational evidence of putative signaling pathways, and changes in receptor localization, affected by treatment with PAOPA. It improves our understanding on the diverse mechanisms of action of allosteric modulators, while advancing PAOPA’s development into a novel drug for the improved treatment of schizophrenia. 相似文献
74.
The structure of a new triterpene lactone, palustrolide, has been elucidated as 3β,23-dihydroxylupan-13β→28 lactone on the basis of physico-chemical studies. In addition, sitosterol, its glucoside, hederagenin, 16,17-dihydroxykauran-19-oic acid and hederagenic acid have been characterized. 相似文献
75.
Validation of host‐specific Bacteroidales quantitative PCR assays and their application to microbial source tracking of drinking water sources in the Kathmandu Valley,Nepal 下载免费PDF全文
76.
This study examined the effects of different gums viz. gum arabic (GA), guar gum (GG), k-carrageenan gum (KG), and xanthan gum (XG) on rheological and 3D printing characteristics of vitamin D (Vit D) enriched orange concentrate (OC) wheat starch (WS) blends. The textural and microstructural properties of printed objects from above mixture were evaluated and compared. The addition of gums induced an increase in apparent viscosity, storage modulus (G′), and loss modulus (G″) of the OC-WS mixtures, while GA decreased the apparent viscosity and G′. Nuclear magnetic resonance (NMR) analysis of 3D printed samples revealed that the movement of transverse time (T2) toward closer to 0 ms indicated an increase in immobilized and bound water populations suggesting the gel formation. The slight shift toward shorter wavelength in FT-IR results for the broadband centered around 3400 cm?1 after addition of gums possibly caused an increase of G′ and load bearing capacity of the blends. 3D printing characteristics revealed that the objects printed using KG containing blend possessed maximum fidelity to the target geometry and good loading bearing capacity, preventing collapsing over time due to the proper G′ value. At tanδ of 0.238, OC-WS-KG mixture achieved the best printing condition. Higher tanδ of GA (0.038) containing samples led to an unwanted collapse of the printed constructs. The objects printed using KG also exhibited the smoothest visible surface as well as microstructure and best mastication properties. Considering the studied features, vitamin D enriched OC with WS-KG was found to be the best match for orange fruit concentrate-based 3D food printing. This work demonstrates the novel ways to develop fortified 3D printed foods. 相似文献
77.
The present study was designed to evaluate the effect of P. aeruginosa on reproductive potential of male mice via a series of in vitro and in vivo experiments. In vitro studies involved sperm parameters, Mg2+ATPase activity and acrosome status. In vivo study employed male mice which in the right vas deferens received 20?μl of either PBS (Group I) or 104 cfu of P. aeruginosa (Group II). The animals were sacrificed on day 3, 7 and 14 and various parameters viz. body weight, TSI (%), bacterial load, spermiogram {i.e. sperm count, motility (%), viability (%) and morphology}, lipid peroxidation and tissue histopathology were evaluated. The results revealed that cell free supernatant of P. aeruginosa resulted in reduced motility, viability, Mg2+dependent ATPase activity and premature acrosomal loss of mouse spermatozoa in vitro. In vivo study showed that in comparison to group I, group II revealed significant alterations in all the parameters on all the days of sacrifice. Further, when reproductive organs of right and left side of mice in group II were compared, the right side demonstrated more devastating effects in terms of altered TSI (%) of testis and cauda epididymis, higher bacterial counts, azoospermia, increased malondialdehyde levels and severe inflammation in tissue histopathology in comparison to left side where bacteria disseminated in reduced numbers, thereby, resulting in insignificant changes in TSI (%), spermiogram, malondialdehyde levels and tissue histology. This study demonstrates that the colonization of P. aeruginosa in male genital tract could be a risk factor for fertility. 相似文献
78.
B. S. Kotlia M. S. Bhalla C. Sharma G. Rajagopalan R. Ramesh M. S. Chauhan P. D. Mathur S. Bhandari S. T. Chacko 《Palaeogeography, Palaeoclimatology, Palaeoecology》1997,130(1-4):307-322
A 52 m thick upper Pleistocene and Holocene terrestrial succession in the Bhimtal-Naukuchiatal basin, south-central Kumaun Himalaya, India was studied using chronological, palaeontological, palynological and δ13C measurements. The section recorded evidence for climatic changes. At least two phases of arid climate and one phase of humid climate were recognised. Preliminary palaeomagnetic studies revealed a reversal of polarity, presumably correlatable with the Mono Lake excursion. Prior to this, no reversal event in the upper Pleistocene-Holocene terrestrial sediments of Indian subcontinent is known. A fossiliferous horizon, discovered in the lower part of the section, consisted of Sorex and Mus. This is the only report of a Late Pleistocene micromammalian assemblage in the Kumaun Himalaya. 相似文献
79.
Lokesh Garg Narinder N. Bhandari Vijay Rani Sant S. Bhojwani 《Plant cell reports》1996,15(11):855-858
Immature endosperm of Acacia nilotica formed a nodular callus on MS medium supplemented with 2,4-D, BAP and CH. In the third passage on this medium, in the dark, the callus differentiated somatic embryos. The embryos germinated on MS only after 15 d pre-treatment on modified MS medium in which major salts were replaced by those of major salts of B5 medium and supplemented with glutamine, CH and CW. Triploid nature of the somatic embryos was confirmed by Feulgen cytophotometry.Abbreviations ABA
abscisic acid
- AC
activated charcoal
- BAP
6-benzylaminopurine
- B5
Gamborg et al. (1968) medium
- CH
casein hydrolysate
- CW
coconut water
- d
days
- MS
Murashige and Skoog (1962) medium
- PEG 4000
polyethylene glycol
- MW
3500–4000
- 2,4-D
2,4-dichlorophenoxyacetic acid 相似文献
80.
Salinity is the major environmental constraint that affects legume productivity by inducing oxidative stress. Individually, both silicon (Si) nutrition and mycorrhization have been reported to alleviate salt stress. However, the mechanisms adopted by both in mediating stress responses are poorly understood. Thus, pot trials were undertaken to evaluate comparative as well as interactive effects of Si and/or arbuscular mycorrhiza (AM) in alleviating NaCl toxicity in modulating oxidative stress and antioxidant defence mechanisms in two Cicer arietinum L. (chickpea) genotypes—HC 3 (salt-tolerant) and CSG 9505 (salt-sensitive). Plants subjected to different NaCl concentrations (0–100 mM) recorded a substantial increase in the rate of superoxide radical (O2 ·?), H2O2, lipoxygenase (LOX) activity and malondialdehyde (MDA) content, which induced leakage of ions and disturbed Ca2+/Na+ ratio in roots and leaves. Individually, Si and AM reduced oxidative burst by strengthening antioxidant enzymatic activities (superoxide dismutase (SOD), catalase (CAT) and guaiacol peroxidase (GPOX)). Si was relatively more efficient in reducing accumulation of stress metabolites, while mycorrhization significantly up-regulated antioxidant machinery and modulated ascorbate-glutathione (ASA-GSH) cycle. Combined applications of Si and AM complemented each other in reducing reactive oxygen species (ROS) build-up by further enhancing the antioxidant defence responses. Magnitude of ROS-mediated oxidative burden was lower in HC 3 which correlated strongly with more effective AM symbiosis, better capacity to accumulate Si and stronger defence response when compared with CSG 9505. Study indicated that Si and/or AM fungal amendments upgraded salt tolerance through a dynamic shift from oxidative destruction towards favourable antioxidant defence system in stressed chickpea plants. 相似文献