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81.
82.
Crustacean and cheliceratan hemocyanins (oxygen-transport proteins) and
insect hexamerins (storage proteins) are homologous gene products, although
the latter do not bind oxygen and do not possess the copper- binding
histidines present in the hemocyanins. An alignment of 19 amino acid
sequences of hemocyanin subunits and insect hexamerins was made, based on
the conservation of elements of secondary structure observed in X-ray
structures of two hemocyanin subunits. The alignment was analyzed using
parsimony and neighbor-joining methods. Results provide strong indications
for grouping together the sequences of the 2 crustacean hemocyanin
subunits, the 5 cheliceratan hemocyanin subunits, and the 12 insect
hexamerins. Within the insect clade, four methionine- rich proteins, four
arylphorins, and two juvenile hormone-suppressible proteins from
Lepidoptera, as well as two dipteran proteins, form four separate groups.
In the absence of an outgroup sequence, it is not possible to present
information about the ancestral state from which these proteins are
derived. Although this family of proteins clearly consists of homologous
gene products, there remain striking differences in gene organization and
site of biosynthesis of the proteins within the cell. Because studies on
18S and 12S rRNA sequences indicate a rather close relationship between
insects and crustaceans, we propose that hemocyanin is the ancestral
arthropod protein and that insect hexamerins lost their copper-binding
capability after divergence of the insects from the crustaceans.
相似文献
83.
Karl Rumbold Hugo JJ van Buijsen Karin M Overkamp Johan W van Groenestijn Peter J Punt J van der Mari?t Werf 《Microbial cell factories》2009,8(1):64
Background
Increasingly lignocellulosic biomass hydrolysates are used as the feedstock for industrial fermentations. These biomass hydrolysates are complex mixtures of different fermentable sugars, but also inhibitors and salts that affect the performance of the microbial production host. The performance of six industrially relevant microorganisms, i.e. two bacteria (Escherichia coli and Corynebacterium glutamicum), two yeasts (Saccharomyces cerevisiae and Pichia stipitis) and two fungi (Aspergillus niger and Trichoderma reesei) were compared for their (i) ability to utilize monosaccharides present in lignocellulosic hydrolysates, (ii) resistance against inhibitors present in lignocellulosic hydrolysates, (iii) their ability to utilize and grow on different feedstock hydrolysates (corn stover, wheat straw, sugar cane bagasse and willow wood). The feedstock hydrolysates were generated in two manners: (i) thermal pretreatment under mild acid conditions followed by enzymatic hydrolysis and (ii) a non-enzymatic method in which the lignocellulosic biomass is pretreated and hydrolyzed by concentrated sulfuric acid. Moreover, the ability of the selected hosts to utilize waste glycerol from the biodiesel industry was evaluated. 相似文献84.
85.
Quezada-Rivera JJ RE Soria-Guerra FS Pérez-Juárez L Martínez-González SE Valdés- Rodríguez NL Vasco-Méndez JF Morales-Domínguez 《Phyton》2019,88(1):25-35
The use of antimicrobial peptides (AMPs) synthesized
by bacteria (bacteriocins) is an alternative for combating multidrug
resistant bacterial strains and their production by recombinant route
is a viable option for their mass production. The bacteriocin E-760
isolated from the genus Enterococcus sp. has been shown to possess
inhibitory activity against Gram-negative and Gram-positive
bacteria. In this study, the expression of a chimeric protein coding
for E-760 in the nucleus of C. reinhardtii was evaluated, as well as,
its antibacterial activity. The synthetic gene E-760S was inserted
into the genome of C. reinhardtii using Agrobacterium tumefaciens.
A transgenic line was identified in TAP medium with hygromycin
and also by PCR. The increment in the culture medium temperature
of the transgenic strain at 35 °C for 10 minutes, increased the
production level of the recombinant protein from 0.14 (Noninduced
culture, NIC) to 0.36% (Induced culture, IC) of total soluble
proteins (TSP); this was quantified by an ELISA assay. Recombinant
E-760 possesses activity against Staphylococcus aureus in 0.34 U
log, Streptococcus agalactiae in 0.48 U log, Enterococcus faecium in
0.36 U log, Pseudomonas aeruginosa in 2 U log and for Klebsiella
pneumoniae, the activity was 0.07 U log. These results demonstrate
that the nucleus transformation of C. reinhardtii can function as
a stable expression platform for the production of the synthetic
gene E-760 and it can potentially be used as an antibacterial agent. 相似文献
86.
Tineke E Buffart Melanie Louw Nicole CT van Grieken Marianne Tijssen Beatriz Carvalho Bauke Ylstra Heike Grabsch Chris JJ Mulder Cornelis JH van de Velde Schalk W van der Merwe Gerrit A Meijer 《BMC medical genomics》2011,4(1):7
Background
Infection with H. pylori is important in the etiology of gastric cancer. Gastric cancer is infrequent in Africa, despite high frequencies of H. pylori infection, referred to as the African enigma. Variation in environmental and host factors influencing gastric cancer risk between different populations have been reported but little is known about the biological differences between gastric cancers from different geographic locations. We aim to study genomic instability patterns of gastric cancers obtained from patients from United Kingdom (UK) and South Africa (SA), in an attempt to support the African enigma hypothesis at the biological level.Methods
DNA was isolated from 67 gastric adenocarcinomas, 33 UK patients, 9 Caucasian SA patients and 25 native SA patients. Microsatellite instability and chromosomal instability were analyzed by PCR and microarray comparative genomic hybridization, respectively. Data was analyzed by supervised univariate and multivariate analyses as well as unsupervised hierarchical cluster analysis.Results
Tumors from Caucasian and native SA patients showed significantly more microsatellite instable tumors (p < 0.05). For the microsatellite stable tumors, geographical origin of the patients correlated with cluster membership, derived from unsupervised hierarchical cluster analysis (p = 0.001). Several chromosomal alterations showed significantly different frequencies in tumors from UK patients and native SA patients, but not between UK and Caucasian SA patients and between native and Caucasian SA patients.Conclusions
Gastric cancers from SA and UK patients show differences in genetic instability patterns, indicating possible different biological mechanisms in patients from different geographical origin. This is of future clinical relevance for stratification of gastric cancer therapy.87.
Background
Genetic disruption of an important phenotype should favor compensatory mutations that restore the phenotype. If the genetic basis of the phenotype is modular, with a network of interacting genes whose functions are specific to that phenotype, compensatory mutations are expected among the genes of the affected network. This perspective was tested in the bacteriophage T3 using a genome deleted of its DNA ligase gene, disrupting DNA metabolism. 相似文献88.
89.
90.