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The glucose transport system of the hyperthermophilic anaerobic bacterium Thermotoga neapolitana 下载免费PDF全文
The glucose transport system of the extremely thermophilic anaerobic bacterium Thermotoga neapolitana was studied with the nonmetabolizable glucose analog 2-deoxy-D-glucose (2-DOG). T. neapolitana accumulated 2-DOG against a concentration gradient in an intracellular free sugar pool that was exchangeable with external source of energy, such as pyruvate, and was inhibited by arsenate and gramicidin D. There was no phosphoenolpyruvate-dependent phosphorylation of glucose, 2-DOG, or fructose by cell extracts or toluene-treated cells, indicating the absence of a phosphoenolpyruvate:sugar phosphotransferase system. These data indicate that D-glucose is taken up by T. neapolitana via an active transport system that is energized by an ion gradient generated by ATP, derived from substrate-level phosphorylation. 相似文献
33.
Serum from 88 pregnant sows and gilts was sampled 24 and 28 days after their first insemination or mating day. The oestrone sulphate (E1S) concentration in the samples was assessed with a commercially available radioimmunoassay kit modified for use with swine serum. The first aim was to test whether it was possible to predict litters of total number <10 piglets at term. The second aim was to compare the use of day 24 or day 28 samples, or of both, in this prediction. 相似文献
34.
Ashraf A Helmy Mostafa A Hamad Ahmed M Aly Tahra Sherif Mostafa Hashem Dalia AH El-Sers Mohammad Semieka 《Annals of surgical innovation and research》2011,5(1):1-9
Background
Biliary tract reconstruction continues to be a challenging surgical problem. Multiple experimental attempts have been reported to reconstruct biliary defects with different materials and variable outcome. Our aim was to evaluate a new method for biliary reconstruction using an isolated pedicled gastric tube in a live animal trial and also to present the first clinical case.Methods
Seven mongrel dogs underwent biliary reconstruction using gastric tube harvested, completely separated from the greater curvature, and based on a vascularized pedicle with the right gastroepiploic vessels. The tube was interposed between the common bile duct (CBD) and the duodenum. Postoperative mortality, morbidity, liver functions, gross and microscopic histological picture were assessed. The first clinical case was also presented where, in a patient with post-cholecystectomy biliary injury, an isolated pedicled gastric tube was interposed between the proximal and distal ends of the CBD.Results
One dog did not recover from anesthesia and another one died postoperatively from septic peritonitis. Five dogs survived the procedure and showed uneventful course and no cholestasis. The mean anastomotic circumference was 4.8 mm (range 4-6) for CBD anastomosis and 6.2 mm (range 5-7) for duodenal anastomosis. Histologically, anastomotic sites showed good evidence of healing. In the first clinical case, the patient showed clinical and biochemical improvement. Endoscopic retrograde cholangiography was feasible and assured patent biliary anastomoses.Conclusion
In mongrel dogs, biliary reconstruction using pedicled gastric tube interposition between CBD and duodenum is feasible with satisfactory clinical results, anastomotic circumference and histological evidence of healing. The technique is also feasible in human and seems to be promising. 相似文献35.
Jo Moore Stephen AC Hawkins Anthony R Austin Timm Konold Robert B Green Ian W Blamire Ian Dexter Michael J Stack Melanie J Chaplin Jan PM Langeveld Marion M Simmons Yvonne I Spencer Paul R Webb Michael Dawson Gerald AH Wells 《BMC research notes》2011,4(1):1-13
Background
Escherichia coli O157:H7 is the most common serovar of enterohemorrhagic E. coli associated with serious human disease outbreaks. Cattle are the main reservoir with E. coli O157:H7 inducing hemorrhagic enteritis in persistent shedding beef cattle, however little is known about how this pathogen affects cattle health. Jejunal Hemorrhage Syndrome (JHS) has unclear etiology but the pathology is similar to that described for E. coli O157:H7 challenged beef cattle suggestive that E. coli O157:H7 could be involved. There are no effective treatments for JHS however new approaches to managing pathogen issues in livestock using prebiotics and probiotics are gaining support. The first objective of the current study was to characterize pathogen colonization in hemorrhaged jejunum of dairy cattle during natural JHS outbreaks. The second objective was to confirm the association of mycotoxigenic fungi in feeds with the development of JHS and also to identify the presence of potential mycotoxins. The third objective was to determine the impact of a prebiotic, Celmanax?, or probiotic, Dairyman's Choice? paste, on the cytotoxicity associated with feed extracts in vitro. The fourth objective was to determine the impact of a prebiotic or a probiotic on E. coli O157:H7 colonization of mucosal explants and a bovine colonic cell line in vitro. The final objective was to determine if prebiotic and probiotic feed additives could modify the symptoms that preceded JHS losses and the development of new JHS cases.Findings
Dairy cattle developed JHS after consuming feed containing several types of mycotoxigenic fungi including Fusarium culmorum, F. poae, F. verticillioides, F. sporotrichioides, Aspergillus flavus, Penicillium roqueforti, P. crustosum, P. paneum and P. citrinum. Mixtures of Shiga toxin - producing Escherichia coli (STEC) colonized the mucosa in the hemorrhaged tissues of the cattle and no other pathogen was identified. The STECs expressed Stx1 and Stx2, but more significantly, Stxs were also present in the blood clot blocking the jejunum. Mycotoxin analysis of the corn crop confirmed the presence of fumonisin, NIV, ZEAR, DON, 15-ADON, 3-ADON, NEO, DAS, HT-2 and T-2. Feed extracts were toxic to enterocytes and 0.1% Celmanax? removed the cytotoxicity in vitro. There was no effect of Dairyman's Choice? paste on feed-extract activity in vitro. Fumonisin, T-2, ZEAR and DON were toxic to bovine cells and 0.1% Celmanax? removed the cytotoxicity in vitro. Celmanax? also directly decreased E. coli O157:H7 colonization of mucosal explants and a colonic cell line in a dose-dependent manner. There was no effect of Dairyman's Choice? paste on E. coli O157:H7 colonization in vitro. The inclusion of the prebiotic and probiotic in the feed was associated with a decline in disease.Conclusion
The current study confirmed an association between mycotoxigenic fungi in the feed and the development of JHS in cattle. This association was further expanded to include mycotoxins in the feed and mixtures of STECs colonizing the severely hemorrhaged tissues. Future studies should examine the extent of involvement of the different STEC in the infection process. The prebiotic, Celmanax?, acted as an anti-adhesive for STEC colonization and a mycotoxin binder in vitro. Future studies should determine the extent of involvement of the prebiotic in altering disease. 相似文献36.
JS Agerholm O Andersen MB Almskou C Bendixen J Arnbjerg GP Aamand US Nielsen F Panitz AH Petersen 《Acta veterinaria Scandinavica》2004,45(3):133
To investigate the congenital complex vertebral malformation syndrome (CVM) in Holstein calves, two breeding studies were
performed including 262 and 363 cows, respectively. Cows were selected from the Danish Cattle Database based on pedigree and
insemination records. Selected cows were progeny of sires with an established heterozygous CVM genotype and pregnant after
insemination with semen from another sire with heterozygous CVM genotype. Following calving the breeders should state, if
the calf was normal and was requested to submit dead calves for necropsy. In both studies, significantly fewer CVM affected
calves than expected were obtained; a finding probably reflecting extensive intrauterine mortality in CVM affected foetuses.
The findings illustrate increased intrauterine mortality as a major potential bias in observational studies of inherited disorders. 相似文献
37.
Shivani M Chidrawar Naeem Khan Y L Tracey Chan Laxman Nayak Paul AH Moss 《Immunity & ageing : I & A》2006,3(1):10-8
Background
Natural killer (NK) cells are cytotoxic lymphocytes that lack CD3 and express variable levels of CD16, CD56 and CD57. In recent years NK cells have been categorised into two major groups based on the level of CD56 expression. This phenotypic classification correlates with functional activity as CD56bright NK cells are the major cytokine producing subset whereas CD56dim NK cells exhibit greater cytotoxic activity. Previous studies have revealed a reduction in total NK cell numbers in association with ageing and this study sought to determine the potential influence of ageing on the number of NK cell subsets within peripheral blood. 相似文献38.
van Hoek AH; van Alen TA; Sprakel VS; Hackstein JH; Vogels GD 《Molecular biology and evolution》1998,15(9):1195-1206
The 18S and 5.8S rDNA genes and the internal transcribed spacers ITS-1 and
ITS-2 of ciliates living in the hindgut of frogs, millipedes, and
cockroaches were analyzed in order to study the evolution of intestinal
protists. All ciliates studied here belong to the genus Nycrotherus.
Phylogenetic analysis revealed that these ciliates from a monophyletic
group that includes the distantly related anaerobic free-living
heterotrichous ciliates Metopus palaeformis and Metopus contortus. The
intestinal ciliates from the different vertebrate and invertebrate hosts
are clearly divergent at the level of their rDNA repeats. This argues for
the antiquity of the associations and a predominantly vertical
transmission. This mode of transmission seems to be controlled primarily by
the behavior of the host. The different degrees of divergence between
ciliates living in different strains of one and the same cockroach species
most likely reflect the different geographical origins of the hosts. In
addition, host switches must have occurred during the evolution of
cockroaches, since identical ciliates were found only in distantly related
hosts. These phenomena prevent the reconstruction of potential cospeciation
events.
相似文献
39.
Reduction of Thromboembolic Events in Meningioma Surgery: A Cohort Study of 724 Consecutive Patients
Christian Valentin Eisenring Marian Christoph Neidert Daniel Sabanés Bové Leonhard Held Johannes Sarnthein Niklaus Krayenbühl 《PloS one》2013,8(11)
Background
Meningiomas are associated with the highest postoperative rate of venous thromboembolic events (VTE) among all intracranial tumors. The aim of this study is to compare two entirely different VTE prophylaxis regimens in 724 consecutive patients undergoing meningioma surgery.Methods
Two cohorts at a single institution treated with different regimens to prevent VTE were reviewed retrospectively. Cohort A (n = 482; 314 females, mean age 57 years, range: 11–87 years) received our institutional regimen during the years 1999–2006, consisting of low-molecular-weight heparin (LMWH) and compression stockings. For cohort B (n = 242; 163 females, mean age 56.8 years, range: 16–90 years), during the years 2008–2010, the management included intraoperative 10°–20° leg elevation with intermittent pneumatic compression (IPC), heparin and LMWH administration. We compared the incidence of the endpoints pulmonary embolism (PE), deep venous thrombosis (DVT), hemorrhage and death, taking into account several known associated risk factors.Results
For all endpoints, we observed a more favorable outcome with the new regimen. The difference in incidence of PEs (cohort A: 38/482, 8%; cohort B: 6/242, 2.5%) reached statistical significance (p = 0.002). In general, patients with skull base meningiomas had a higher risk for PE (OR 2.77). Regarding VTE prophylaxis, an adjusted subgroup analysis suggests that the new regimen is particularly beneficial for patients with skull base meningiomas.Conclusions
We recommend perioperative prophylaxis using a management composed of intraoperative leg-elevation, IPC, early heparin administration and LMWH to reduce the risk for PE. 相似文献40.
Timm Konold A Robin Sayers Amanda Sach Gemma E Bone Steven van Winden Gerald AH Wells Marion M Simmons Michael J Stack Angus Wear Steve AC Hawkins 《BMC veterinary research》2010,6(1):53