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61.
The functional feeding groups and diversity of macroinvertebrate communities associated with duckweed mats in the New Years River (two sites) and Bloukrans River (two sites), Eastern Cape province, South Africa, were assessed. Duckweed (Lemnaceae) is a ubiquitous family of floating macrophytes. A total of 41 macroinvertebrate families were collected monthly over a six-month period from February to July 2014. Duckweed biomass in both rivers was highly variable both temporally and spatially. The majority of identified macroinvertebrate taxa were predators and detritivores, with a small percentage of herbivores. An average of approximately 26% of the macroinvertebrate taxa found were from families that include species from more than one functional feeding group. Although overall measures of diversity and ecosystem health (Fisher’s α and Simpson’s index) remained constant over time in the New Years River, significant differences in macroinvertebrate community structure were seen between sites and months on both rivers, with dissimilarity being driven by a larger number of species in the New Years River. This high variability within macroinvertebrate assemblages probably reflects a combination of heterogeneous duckweed distribution, variation in physico-chemistry, opportunistic behaviours of macroinvertebrate predators and/or successional colonisation of duckweed mats. 相似文献
62.
Sialylation is a biosynthetic process occurring in the trans compartments
of the Golgi apparatus. Corresponding evidence is based on localization and
biochemical studies of alpha2, 6(N)-sialyltransferase (ST6Gal I) as
previously reported. Here we describe generation and characterization of
polyclonal antibodies to recombinant rat alpha2,3(N)-sialyltransferase
(ST3Gal III) expressed as a soluble enzyme in Sf9 cells or as a
beta-galactosidase-human-ST3Gal III fusion- protein from E.coli ,
respectively. These antibodies were used to localize ST3Gal III by
immunofluorescence in various cell lines and rat kidney tissue sections. In
transiently transfected COS cells the antibodies directed to soluble
sialyltransferase or the sialyltransferase portion of the fusion-protein
only recognized the recombinant antigen retained in the endoplasmic
reticulum. However, an antibody fraction crossreactive with
beta-galactosidase recognized natively expressed ST3Gal III which was found
to be colocalized with beta1, 4-galactosyltransferase in the Golgi
apparatus of several cultured cell lines. Antibodies affinity purified on
the beta- galactosidase-ST3Gal III fusion-protein column derived from both
antisera have then been used to localize the enzyme in perfusion-fixed rat
kidney sections. We found strong staining of the Golgi apparatus of tubular
epithelia and a brush-border-associated staining which colocalized with
cytochemical staining of the H+ATPase. This subcellular localization was
not observed for ST6Gal I which localized to the Golgi apparatus. These
data show colocalization in the Golgi apparatus and different post-Golgi
distributions of the two sialyltransferases.
相似文献
63.
Tara C. Gangadhar Samantha L. Savitch Stephanie S. Yee Wei Xu Alexander C. Huang Shannon Harmon David B. Lieberman Devon Soucier Ryan Fan Taylor A. Black Jennifer J. D. Morrissette Neeraj Salathia Jill Waters Shile Zhang Jonathan Toung Paul van Hummelen Jian‐Bing Fan Xiaowei Xu Ravi K. Amaravadi Lynn M. Schuchter Giorgos C. Karakousis Wei‐Ting Hwang Erica L. Carpenter 《Pigment cell & melanoma research》2018,31(1):73-81
To determine the feasibility of liquid biopsy for monitoring of patients with advanced melanoma, cell‐free DNA was extracted from plasma for 25 Stage III/IV patients, most (84.0%) having received previous therapy. DNA concentrations ranged from 0.6 to 390.0 ng/ml (median = 7.8 ng/ml) and were positively correlated with tumor burden as measured by imaging (Spearman rho = 0.5435, p = .0363). Using ultra‐deep sequencing for a 61‐gene panel, one or more mutations were detected in 12 of 25 samples (48.0%), and this proportion did not vary significantly for patients on or off therapy at the time of blood draw (52.9% and 37.5% respectively; p = .673). Sixteen mutations were detected in eight different genes, with the most frequent mutations detected in BRAF, NRAS, and KIT. Allele fractions ranged from 1.1% to 63.2% (median = 29.1%). Among patients with tissue next‐generation sequencing, nine of 11 plasma mutations were also detected in matched tissue, for a concordance of 81.8%. 相似文献
64.
Lymphocyte locomotion and attachment on two-dimensional surfaces and in three-dimensional matrices 总被引:9,自引:3,他引:6
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The adhesion and locomotion of mouse peripheral lymph node lymphocytes on 2-D protein- coated substrata and in 3-D matrices were compared. Lymphocytes did not adhere to, or migrate on, 2-D substrata suck as serum- or fibronectin-coated glass. They did attach to and migrate in hydrated 3-D collagen lattices. When the collagen was dehydrated to form a 2-D surface, lymphocyte attachment to it was reduced. We propose that lymphocytes, which are poorly adhesive, are able to attach to and migrate in 3-D matrices by a nonadhesive mechanism such as the extension and expansion of pseudopodia through gaps in the matrix, which could provide purchase for movement in the absence of discrete intermolecular adhesions. This was supported by studies using serum-coated micropore filters, since lymphocytes attached to and migrated into filters with pore sizes large enough (3 or 8 mum) to allow pseudopod penetration but did not attach to filters made of an identical material (cellulose esters) but of narrow pore size (0.22 or 0.45 mum). Cinematographic studies of lymphocyte locomotion in collagen gels were also consistent with the above hypothesis, since lymphocytes showed a more variable morphology than is typically seen on plane surfaces, with formation of many small pseudopodia expanded to give a marked constriction between the cell and the pseudopod. These extensions often remained fixed with respect to the environment as the lymphocyte moved away from or past them. This suggests that the pseudopodia were inserted into gaps in the gel matrix and acted as anchorage points for locomotion. 相似文献
65.
Matheus S Gasparini Leandro M dos Santos Ahmad MA Hamade Luísa G Gross Arthur P Favarato Jos PC de Vasconcellos Mnica B de Melo Pierina L Parise Camila L Simeoni Natlia B Silva Marcelo A da Silva Mori Andr S Vieira Alessandro dos Santos Farias Fabiana Granja Angelica Z Schreiber Maria L Moretti Jos L Proena-Modena Mnica Alves 《Experimental biology and medicine (Maywood, N.J.)》2021,246(23):2495
66.
67.
Fabíola C Toledo Juliana E Perobelli Flávia PC Pedrosa Janete A Anselmo-Franci Wilma DG Kempinas 《Reproductive biology and endocrinology : RB&E》2011,9(1):1-9
Background
Hyperglycemia can impair the male reproductive system in experimental animals and in men during reproductive age. Studies have shown that vitamin C has some good effects on male reproductive system, and therefore vitamin C treatment could attenuate the dysfunctions in this system caused by hyperglycemia. Thus, the objective of this work was to evaluate whether vitamin C treatment could attenuate reproductive dysfunctions in hyperglycemic male rats.Methods
Adult male rats were divided into 3 groups: a normoglycemic (n = 10) and two hyperglycemic (that received a single dose of streptozotocin - 40 mg/kg BW). The two last groups (n = 10 per group) were divided into: hyperglycemic control (Hy) and hyperglycemic + 150 mg of vitamin C (HyC), by gavage during 30 consecutive days. The normoglycemic and hyperglycemic control groups received the vehicle (water). The first day after the treatment, the rats were anesthetized and killed to evaluate oxidative stress biomarkers (TBARS, SOD, GSHt and GSH-Px) in the erythrocytes, body and reproductive organ weights, sperm parameters, plasma hormone levels (FSH, LH and testosterone), testicular and epididymal histo-morphometry and histopathology.Results
Compared with the normoglycemic animals, hyperglycemic control rats showed reduced weight of the body and reproductive organ but testis weight was maintained. It was also observed reduction of testosterone and LH levels, seminiferous tubular diameter, sperm motility and sperm counts in the epididymis. In addition, there was an increase in morphological abnormalities on spermatozoa as well as in oxidative stress level. Vitamin C reduced the oxidative stress level, diminished the number of abnormal sperm, and increased testosterone and LH levels and seminiferous tubular diameter but did not show improvement of sperm motility in relation to the hyperglycemic control group. Hyperglycemia caused a rearrangement in the epididymal tissue components (stroma, ephitelium and lumen) as demonstrated by the stereological analysis results. However, this alteration was partially prevented by vitamin C treatment.Conclusions
We conclude that vitamin C partially attenuated some male reproductive system dysfunctions in hyperglycemic rats. 相似文献68.
69.
The pathogenesis of intraocular tuberculosis remains poorly understood partly due to the lack of adequate animal models that accurately simulate human disease. Using a recently developed model of ocular tuberculosis following aerosol infection of guinea pigs with Mycobacterium tuberculosis, we studied the microbiological, histological, and clinical features of intraocular tuberculosis infection. Viable tubercle bacilli were cultivated from all eyes by Day 56 after aerosol delivery of ~200 bacilli to guinea pig lungs. Choroidal tuberculous granulomas showed reduced oxygen tension, as evidenced by staining with the hypoxia-specific probe pimonidazole, and expression of vascular endothelial growth factor (VEGF) was detected in the retinal pigment epithelium (RPE) and photoreceptors. Fundoscopic examination of M. tuberculosis-infected guinea pig eyes revealed altered vascular architecture and chorioretinal hemorrhage by Day 56 after infection. This model may be useful in further elucidating the pathogenesis of ocular tuberculosis, as well as in developing tools for diagnosis and assessment of antituberculosis treatment responses in the eye. 相似文献
70.
Singh PP Smith VL Karakousis PC Schorey JS 《Journal of immunology (Baltimore, Md. : 1950)》2012,189(2):777-785
More than 2 billion people are infected with Mycobacterium. tuberculosis; however, only 5-10% of those infected will develop active disease. Recent data suggest that containment is controlled locally at the level of the granuloma and that granuloma architecture may differ even within a single infected individual. Formation of a granuloma likely requires exposure to mycobacterial components released from infected macrophages, but the mechanism of their release is still unclear. We hypothesize that exosomes, which are small membrane vesicles containing mycobacterial components released from infected macrophages, could promote cellular recruitment during granuloma formation. In support of this hypothesis, we found that C57BL/6 mouse-derived bone marrow macrophages treated with exosomes released from M. tuberculosis-infected RAW264.7 cells secrete significant levels of chemokines and can induce migration of CFSE-labeled macrophages and splenocytes. Exosomes isolated from the serum of M. bovis bacillus Calmette-Guérin-infected mice could also stimulate macrophage production of chemokines and cytokines ex vivo, but the level and type differed during the course of a 60-d infection. Of interest, the exosome concentration in serum correlated strongly with mouse bacterial load, suggesting some role in immune regulation. Finally, hollow fiber-based experiments indicated that macrophages treated with exosomes released from M. tuberculosis-infected cells could promote macrophage recruitment in vivo. Exosomes injected intranasally could also recruit CD11b(+) cells into the lung. Overall, our study suggests that exosomes may play an important role in recruiting and regulating host cells during an M. tuberculosis infection. 相似文献