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1.
A system of intracellular peptidoglycan hydrolases of Xanthomonas campestris XL-1 comprises about 10 enzymes of different localization and substrate specificity. Seven enzymes (A1-A7) are localized in cytosol, one enzyme (A8) in periplasm, and two enzymes (A9, A10) were found in the fraction of cell walls and membranes. While the culture is entering the logarithmic growth stage from the stationary stage, a change occurs in the activity of the cytosolic enzymes: A1 significantly increases, and A5 and A6 decrease. The spectrum of cytosolic enzymes also depends on the growth medium composition. The enzyme A7 present in cells secreting extracellular enzymes (medium 5/5) was not found in non-secreting cells (LB medium). Unlike extracellular enzymes, intracellular peptidoglycan hydrolases are primarily acidic proteins. The data indicate that the system of intracellular peptidoglycan hydrolases of X. campestris is under complex and strict regulation. 相似文献
2.
J. Kieler P. Briand M. C. Van Peteghem M. Mareel 《In vitro cellular & developmental biology. Plant》1979,15(10):758-771
Summary Two types of apparently spontaneous malignant alterations of fibroblastlike ST/a mouse lung cells (ST-L cells) grown in vitro
are described. One type is characterized by a high tumorigenic potential of the altered cells in nonconditioned syngeneic
recipients, a fibro-blastlike morphology with cell surface showing very few microvilli by scanning electron-microscopy (SEM),
and a growth pattern typical of nontransformed cells. These cells were described as R− cells. The other type is characterized by a low tumorigenic potential in nonconditioned, immunocompetent syngeneic recipients,
rounding up of the cells which by SEM showed numerous microvilli on the surface, and a growth pattern typical of transformed
cells. These cells were described as round cells or R+ cells. In immunoincompetent mice, R+ cells readily produced sarcomas, which grew faster than those produced by R− cells. Both types of ST-L cells expressed murine leukemia virus (MuLV) when tested in a peroxidase anti-p30 plaque test.
The concentration of murine leukemia virus envelope glycoprotein (gp70) has previously (5) been shown to be threefold higher
in R+ cells compared to R− cells. Furthermore, round-cell transformation was accompanied by the development of crossreacting rejection antigens protective
against a secondary challenge with Ehrlich ascites tumor and with syngeneic dimethylbenzanthracene induced ST/a mouse leukemia
(STABAL). A similar protection was obtained by preimmunization with a cloned embryonic feral mouse cell line (SC-1) infected
with ST-L virus as well as with virus-free SC-1 cells, suggesting the presence of rejection antigens both of viral (gp70)
and nonviral origin.
Sponsored by the Danish Cancer Society.
Supported by the Kankerfonds van de Algemene Spaar-en Lijfrentekas.
The SC-1 cell line was originally provided by contract E-73-2001-N01 within the Special Virus-Cancer Program NIH, USPHS, through
the courtesy of Walter A. Nelson-Rees, Naval Biomedical Research Laboratory, Oakland, California, and Wallace P. Rowe, Laboratory
of Viral Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland.
The financial support of the Daell Foundation, the Schepler Foundation, the Jorgen Holm Foundation and the Danish National
Research Foundation is gratefully acknowledged. 相似文献
3.
Under conditions of a few behavioral tests on rats, we examined the psychotropic activity of novel N-uronoyl derivatives of
amino acids: (i) N-(1,2:3,4-di-O-isopropylidene-α-D-galactopyranuronoyl-β-alanine (DAGU-Ala), (ii) DAGU-glycyl-D,L-glutamic
acid (DAGU-Gly-Glu), and (iii) DAGU-glycyl-glycine (DAGU-Gly-Gly) injected i.p. in a 50 mg/kg dose. In an open-field test,
DAGU-Gly-Glu and DAGU-GLy-Gly showed antistress properties (they decreased the intensity of locomotion, decreased the number
of defecation acts, and intensified the research activity), while DAGU-Ala possessed a psychostimulating effect (intensification
of locomotor and research activity and an increase in the number of defecations). In the “black-and-white chamber” test, only
DAGU-Gly-Gly exerted an anxiolytic effect; it somewhat increased the frequency and duration of emergings of animals from the
dark section and duration of visits to the illuminated section of the chamber. DAGU-GLy-Glu manifested antidepressant properties;
it increased the time of active swimming of the animal in the Porsolt test and decreased the duration of passive “hanging”
of rats in the “suspension by the tail” test.
Neirofiziologiya/Neurophysiology, Vol. 39, No. 1, pp. 52–61, January–February, 2007. 相似文献
4.
T. L. Karaseva B. A. Lobasyuk S. G. Soboleva E. A. Kostenko S. A. Andronati 《Neurophysiology》2000,32(1):8-11
The neuropharmacological profile of 4-phenyl-1-[4-(2-naphtalimido)butyl]-piperazine (PNBP), a compound that possesses a high
affinity for the serotonin receptors of 1A-type (5-HT1A) and lacks an anxiolytic action, has been studied. Intracerebral administration of PNBP to rats through implanted cannulae
into the hippocampal region resulted in no substantial behavioral changes during “open field” and “conflict situation” tests,
as compared with those of control animals. At the same time, the behavioral effects of intraperitoneal administration of 10
mg/kg buspirone were completely abolished if buspirone had been jointly administered with 10 mg/kg PNBP. Moreover, combined
application of 0.3 mg/kg PNBP and 0.3 mg/kg 8-OH-DPAT, an agonist of 5-HT1A receptors, almost completely abolished the components of “serotonin syndrome” (prone position and stamping of the forepaws)
in animals under study. These findings allowed us to conclude that PNBP has the properties of a competitive antagonist of
buspirone and 8-OH-DPAT. 相似文献
5.
A new species of notothenioid fish, Pogonophryne bellingshausenensis n. sp., is described from the Bellingshausen Sea, Antarctica. The new species belongs to the dorsally-spotted “mentella”
group of the genus and is characterized by having a short (about 13% SL) mental barbel with a short (about 16% of barbel length),
narrow (barely wider than the stalk), and relatively inconspicuous terminal expansion composed of short, irregular, fingerlike
processes. Compared to most other dorsally-spotted species of Pogonophryne (“barsukovi”, “marmorata”, and “mentella” groups), P. bellingshausenensis has a relatively wide (about 7% SL) interorbital region. An unspotted patch on the median dorsal surface of the head, posterior
to the posttemporal ridges and anterior to the first dorsal fin, has not been observed previously in any dorsally-spotted
species. The holotype was collected at 1,947 m, one of the deepest records for any species of Pogonophryne. A revised key to the ten species of the “mentella” group of Pogonophryne is also provided. 相似文献
6.
【目的】旨在研究光滑鳖甲Anatolica polita肽聚糖识别蛋白(peptidoglycan recognition proteins, PGRPs)基因ApPGRP表达模式及其对下游免疫相关基因的表达调控,以及重组蛋白ApPGRP与细菌的结合能力。【方法】构建原核表达载体pET-28a-ApPGRP,转化大肠杆菌Escherichia coli BL21(DE3),诱导表达并纯化重组蛋白His-ApPGRP,分别测定其与金黄色葡萄球菌Staphylococcus aureus和肽聚糖(peptidoglycan, PGN)的结合能力。金黄色葡萄球菌S.aureus刺激后,利用qRT-PCR检测光滑鳖甲6龄幼虫体内ApPGRP、抗菌肽基因ApAttacin2和ApAttacin1、防御素基因ApDefensin、丝氨酸蛋白酶基因ApSP和丝氨酸蛋白酶抑制剂基因ApSerpin等免疫相关基因的表达水平;采用RNAi技术沉默光滑鳖甲6龄幼虫体内ApPGRP基因的表达,并利用qRT-PCR分别检测RNAi处理以及RNAi后再用S.aureus刺激时幼虫体内上述基因的表达水平变化。【结果】通过原核表达获得了重组蛋白His-ApPGRP,其具有结合金黄色葡萄球菌和肽聚糖的能力。注射金黄色葡萄球菌后,检测的光滑鳖甲6龄幼虫免疫相关基因(ApSP除外)的表达都显著上调;RNAi沉默光滑鳖甲6龄幼虫ApPGRP后,其他免疫相关基因表达量均显著降低,其响应金黄色葡萄球菌刺激后的表达量也显著低于对照组。【结论】这些结果表明,ApPGRP在光滑鳖甲免疫防御中起着识别外源微生物,激活信号通路并调控抗菌肽表达的作用。 相似文献
7.
The species composition and distribution of marine plants on the fringing reef of Secoko Island were studied before and after the mass coral mortality in 1998. The study showed that changes in the bottom communities that occurred after bleaching of corals were caused by the presumed development of marine plants substituting reef-building corals on the bottom. The number of algal species grew from 211 to 345. The projective cover (PC) of hard substrate with macroalgae increased: in 1998, it was 1–10% in the subtidal zone and 20–50% in the intertidal zone, while in 2002 through 2005, the PC reached 71% in the subtidal and 40–85% in the intertidal zone. It is assumed that the phase of the “plant reef” on Sesoko Island is a temporary event, and that the coral reef can recover within several decades, unless a natural catastrophe occurs again. 相似文献
8.
Two-dimensional gel electrophoresis and immunoassays revealed several proteins of the secretory subproteome of Corynebacterium glutamicum to be glycosylated. By genome-wide searches for genes involved in glycosylation, the C. glutamicum gene cg1014 was found to exhibit significant similarity to eukaryotic protein-O-mannosyltransferases (PMTs) and to a recently identified orthologue of Mycobacterium tuberculosis, Rv1002c, which is responsible for protein-O-mannosylation. The putative membrane protein Cg1014 showed the same predicted transmembrane topology as Saccharomyces cerevisiae PMT1 and M. tuberculosis Rv1002c along with conserved amino acid residues responsible for catalytic activity. Deletion of the C. glutamicum pmt gene (cg1014) caused a complete loss of glycosylation of secreted proteins including the resuscitation promoting factor 2 (Rpf2), which is involved in intercellular communication and growth stimulation of C. glutamicum. Because the gene pmt as well as rpf genes are present in the genomes of all actinobacteria sequenced so far, this work provides new insights into bacterial protein glycosylation and new opportunities to elucidate the molecular mechanisms of Rpf activity in pathogenic growth and infection. 相似文献
9.
K. Jacobs 《Human Evolution》1992,7(4):33-48
Odontometric data are reported for Oleneostrovskii mogilnik, a Mesolithic cemetery in the Karelian USSR. Containing the skeletal
remains of 148 individuals and dated to 7500b.p., it is the largest and oldest of the known peri-Baltic Mesolithic cemeteries.
The dental data from this site are compared to those from Skateholm, where dental dimensions closely approximate the mean
tooth sizes for all late Mesolithic European material. Olenii ostrov possesses a significantly smaller dentition, despite
antedating the Skateholm sample by 1500 years. Geographic, archaeological, linguistic and ancillary dental data are discussed
which argue strongly for the presence in Mesolithic northern Europe of at least two quasi-isolated human mating networks.
One of these, documented by Olenii ostrov, may also represent the earliest evidence for the establishment in the taiga zone
of populations whose descendants are the modern Saami (=”Lapps”). 相似文献
10.
A Simple Method for Developing Microsatellite Markers using Amplified Fragments of Inter-simple Sequence Repeat (ISSR) 总被引:21,自引:0,他引:21
10 A primer IP1 designed from the sequenced region at one end of the microsatellite and for nested PCR another primer IP2 based
on the sequence between IP1 and the microsatellite were prepared. These two primers were used to determine the other sequence
flanking the microsatellite by a “walking” method. With this approach, we developed several microsatellite markers from Salix reinii, Pinus densiflora and Robinia pseudoacacia, respectively. The absence of enrichment processes and screening procedures makes it easier to develop microsatellite markers,
and this approach provides an alternative for the development of microsatellite markers in any organism.
Received 23 April 2001/ Accepted in revised form 11 June 2001 相似文献
11.
A dense accumulation of the phototrophic consortium “Pelochromatium roseum” in a small, eutrophic, freshwater lake (Dagowsee, Brandenburg, Germany) was investigated. Within the chemocline, the number
of epibionts of the consortia represented up to 19% of the total number of bacteria. Per “P. roseum” a mean value of 20 epibionts was determined. Similar to other aquatic habitats, consortia in the Dagowsee were found only
at low light intensities (< 7 μmol quanta m–2 s–1) and low sulfide concentrations (0–100 μM). In dialysis cultures of “P. roseum”, bacterial cells remained in a stable association only when incubated at light intensities between 5 and 10 μmol quanta
m–2 s–1. Intact consortia from natural samples had a buoyant density of 1046.8 kg m–3, which was much higher than that of ambient chemocline water (995.8 kg m–3). Under environmental conditions and without motility, this density difference would result in rapid sedimentation of consortia
toward the lake bottom. Our results indicate that (1) consortia are adapted to a very narrow regime of light intensities and
sulfide concentrations, (2) motility and tactic responses must be of ecological significance for the colonization of the free
water column of lakes, and (3) phototrophic growth of consortia can be explained only by a cycling of sulfur species in the
chemocline, possibly within the consortia themselves.
Received: 27 May 1997 / Accepted: 16 September 1997 相似文献
12.
Nuria Saperas Manel Chiva David C. Pfeiffer Harold E. Kasinsky Juan Ausió 《Journal of molecular evolution》1997,44(4):422-431
We have characterized for the first time SNBPs from the hagfish Eptatratus stouti (Myxini) and the lamprey Lampetra tridentatus (Cephalaspidomorphi) and have found that histones are the major protein components of the sperm of these agnathans. We have
also conducted a systematic analysis of SNBPs from different groups of chondrichthyan fishes, including the skate Raja rhina and seven species of sharks. Together with our previous data showing the sporadic nature of SNBP evolution in bony fish (Saperas,
N., Ausio, J., Lloris, D. and Chiva, M. [1994] J. Mol. Evol. 39: 282–295), the present study provides a unique insight into the overall evolutionary complexity and variability of the
nuclear sperm proteins of fishes. It would appear that despite the discontinuous evolution of these proteins, the macroevolutionary
pattern of histone (H type) → protamine-like (PL type) → protamine (P type) has been conserved in fish evolution, as it has
in the evolution of other Deuterostomes.
Received: 11 June 1996 / Accepted: 6 August 1996 相似文献
13.
Seven Middle Devonian (latest Givetian or earliest Frasnian) gastropod species are described from the quarry of Oetelshofen
near Dornap (Bergisches Land, northwestern Rheinisches Schiefergebirge, Germany). New species areMurchisonia dornapica, Araeonema osterholzensis, Plagiothyra isekei andMacrochilina drozdzewski. Additionally, a new subspecies,Euryzone delphinuloides oetelshofensis and aNaticopsis-like species and their typical facial occurrence are discussed. The existence of predation is proved by a bore-hole inMacrochilina drozdzewski; the predator itself is not yet identified with certainty.
相似文献
14.
Juan Ausiö Manfred L. J. Van Veghel Raquel Gomez Daniel Barreda 《Journal of molecular evolution》1997,45(1):91-96
We have isolated and characterized for the first time, the SNBPs from an organism (Neofibularia nolitangere) of the phylum Porifera (Sponges). We have shown that these proteins consist of histones which, as expected, exhibit an amino
acid composition very similar to that of other eukaryotic histones. The finding of histones in the sperm of these primitive
organisms provides support to the notion that histones (SNBPs of the histone, H, type) were the proteins present at the onset
of SNBP evolution. In contrast, a discrete number of alternative SNBP types (protamine-like, PL; protamine, P, types) seem
to have appeared later on in the course of evolution and are found in both protostomes and deuterostomes, most likely as a
result of processes of parallel evolution.
Received: 5 March 1997 / Accepted: 6 March 1997 相似文献
15.
Conflict Among Individual Mitochondrial Proteins in Resolving the Phylogeny of Eutherian Orders 总被引:19,自引:0,他引:19
Ying Cao Axel Janke Peter J. Waddell Michael Westerman Osamu Takenaka Shigenori Murata Norihiro Okada Svante Pääbo Masami Hasegawa 《Journal of molecular evolution》1998,47(3):307-322
The phylogenetic relationship among primates, ferungulates (artiodactyls + cetaceans + perissodactyls + carnivores), and
rodents was examined using proteins encoded by the H strand of mtDNA, with marsupials and monotremes as the outgroup. Trees
estimated from individual proteins were compared in detail with the tree estimated from all 12 proteins (either concatenated
or summing up log-likelihood scores for each gene). Although the overall evidence strongly suggests ((primates, ferungulates),
rodents), the ND1 data clearly support another tree, ((primates, rodents), ferungulates). To clarify whether this contradiction
is due to (1) a stochastic (sampling) error; (2) minor model-based errors (e.g., ignoring site rate variability), or (3) convergent
and parallel evolution (specifically between either primates and rodents or ferungulates and the outgroup), the ND1 genes
from many additional species of primates, rodents, other eutherian orders, and the outgroup (marsupials + monotremes) were
sequenced. The phylogenetic analyses were extensive and aimed to eliminate the following artifacts as possible causes of the
aberrant result: base composition biases, unequal site substitution rates, or the cumulative effects of both. Neither more
sophisticated evolutionary analyses nor the addition of species changed the previous conclusion. That is, the statistical
support for grouping rodents and primates to the exclusion of all other taxa fluctuates upward or downward in quite a tight
range centered near 95% confidence. These results and a site-by-site examination of the sequences clearly suggest that convergent
or parallel evolution has occurred in ND1 between primates and rodents and/or between ferungulates and the outgroup. While
the primate/rodent grouping is strange, ND1 also throws some interesting light on the relationships of some eutherian orders,
marsupials, and montremes. In these parts of the tree, ND1 shows no apparent tendency for unexplained convergences.
Received: 5 December 1997 / Accepted: 24 February 1998 相似文献
16.
Identification of RAPD markers linked to a Phytophthora fragariae resistance gene (Rpf1) in the cultivated strawberry 总被引:2,自引:0,他引:2
K. M. Haymes B. Henken T. M. Davis W. E. van de Weg 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,94(8):1097-1101
Bulked segregant analysis (BSA) was used to identify seven random amplified polymorphic DNA (RAPD) markers linked to the
Rpf 1 gene. Rpf 1 confers resistance to Phytophthora fragariae var. fragariae, the causal agent of red stele root rot in Fragaria spp. The bulked DNAs represented subsets of a F1 population obtained from the cross Md683×Senga Sengana which consisted of 60 plants and segregated in a 1:1 ratio for resistance
or susceptibility to race 2.3.4 isolate NS2 of P. fragariae. Seven markers were shown to be linked to Rpf 1 and were generated from four primers; five of these markers were in coupling phase and two in repulsion phase with respect
to the gene. A linkage map of this resistance gene region was generated using JoinMap 2.0TM. The manner in which Rpf 1 and the linked markers co-segregated indicated that they are inherited in a disomic fashion. These markers could enable gene
pyramiding and marker-assisted selection of resistance genes in strawberry breeding programmes.
Received: 26 August 1996 / Accepted: 20 December 1996 相似文献
17.
The effect of NAD(P) and analogs of this nucleotide on nitrogenase activity in Rhodospirillum rubrum has been studied. Addition of NAD+ to nitrogen fixing Rsp. rubrum leads to inhibition of nitrogenase. NADP+ has the same effect but NADH or analogs modified in the nicotinamide portion do not cause inhibition. In contrast to ammonium
ions, addition of NAD+ leads to inhibition of nitrogenase in cells that have been N-starved under argon. The inhibitory effect of NAD+ is more pronounced at lower light intensities. Addition of NAD+ also leads to inhibition of glutamine synthetase, a phenomenon also occurring when “switchoff” is produced by the addition
of effectors such as ammonium ions or glutamine. It is also shown that NAD+ is taken up by Rsp. rubrum cells. 相似文献
18.
Masazumi Mitani 《Primates; journal of primatology》1986,27(4):397-412
Japanese monkeys often exchange the particular vocal sound, “coo,” especially when they feed or move as a group. It was considered
that the “coo” sound had no positive social meaning, perhaps because the “coo” sound network and its function were hidden
behind other behavioral observations. For identification of the vocalizer only from hearing the “coo” sound, three phonetic
values, i.e., the “fundamental,” “duration,” and “formants,” plus other characteristics were used as indices of voiceprints. The results indicated that these were effective for identifying
the vocalizer in two-thirds of the adults in the study troop which was composed of 12 adults and 16 immature members. The
“coo” sound exchange network among the troop members (adults) was drawn on the basis of the voiceprint identification. The
network showed three characteristics as follows: (1) matriarchs of the kin-groups frequently exchanged “coo” sounds with each
other; (2) the other females exchanged “coo” sounds mostly within their own kin-groups; and (3) males seldom participated
in the “coo” sound exchange. This suggests that “coo” sound exchange plays a central role for the matriarch of kin-groups
in binding each kin-group and, ultimately, in binding all members together into an organized troop. 相似文献
19.
The histomorphology of the digestive gland of the bivalve mollusk Crenomytilus grayanus from Sivuchya Bay, which is located in the southwest of Peter the Great Bay and subjected to the effect of polluted waters of Tumannaya River, was studied. Pathological changes of the digestive tubules, channels, and connective tissue of the gland were recorded in all the mussels studied. The epithelium of the tubules and channels was characteristic with erosive disturbances and by heavy vacuolization of digestive cells; connective tissue of the gland was specified by cells with lipofuscin (granulocytomes) and by foci of cells necrosis and lysis. Nervous fibers running in the gland were swollen in some mollusks. Strongly basophilic spherical formations, presumably one of the development stages of a parasitic plasmodium, were found in the granulocytomes and among vesicular cells of connective tissue of all the mussels. It was concluded that pathological changes in digestive gland of Gray’s mussel might be caused by chronic pollution of the bay and by parasitic invasion. 相似文献
20.
Yingxin Huang Xueyong Zhao Hongxuan Zhang Wisdom Japhet Xiaoan Zuo Yayong Luo Gang Huang 《Journal of Plant Biology》2009,52(3):210-219
We monitored the allometric effects for greenhouse-grown Agriophyllum squarrosum plants in response to variations in population density and the availability of soil nutrients and water. Biomass allocations
were size-dependent. The plasticity of roots, stems, leaves, and reproductive effort was “true” in response to changes in
nutrient content. At a low level of soil minerals, plants allocated more resources to the development of roots and reproductive
organs than to leaves, but data for stem allocations were consistent for tradeoffs between the effects of nutrients and plant
size. The plasticities of leaf allocation and reproductive effort were “true” whereas those of root and stem allocations were
“apparent” in response to fluctuations in soil water, being a function of plant size. Decreasing soil water content was associated
with higher leaf allocation and lower reproductive effort. Except for this “apparent” plasticity of leaf allocation, none
was detected with population density on biomass allocation. Architectural traits were determinants of the latter. For roots,
the determining trait was the ratio of plant height to total biomass; for stems and reproduction, plant height; and for leaves,
the ratio of branch numbers to plant height. 相似文献