共查询到20条相似文献,搜索用时 15 毫秒
1.
Peng Chen Yiran Zhu Huiyu Wan Yang Wang Pan Hao Ziqiang Cheng Yongxia Liu Jianzhu Liu 《Biological trace element research》2017,180(2):285-296
This study aimed to investigate the effects of selenium on the ion profiles in the heart, liver, spleen, and kidney through the oral administration of hexavalent chromium. Approximately 22.14 mg/kg b.w. K2Cr2O7 was added to water to establish a chronic poisoning model. Different selenium levels (0.00, 0.31, 0.63, 1.25, 2.50, and 5.00 mg Na2SeO3/kg b.w.) around the safe dose were administered to the experimental group model. Ca, Mg, Mn, Fe, Cu, and Zn were detected in the organs through flame atomic absorption spectrometry after these organs were exposed to K2Cr2O7 and Na2SeO3 for 14, 28, and 42 days. Results showed that these elements exhibited various changes. Ca contents declined in the heart, liver, and spleen. Ca contents also decreased on the 28th day and increased on the 42nd day in the kidney. Mn contents declined in the heart and spleen but increased in the kidney. Mn contents also decreased on the 28th day and increased on the 42nd day in the liver. Cu contents declined in the heart and spleen. Cu contents increased on the 28th day and decreased on the 42nd day in the liver and kidney. Zn contents declined in the heart and spleen. Zn contents increased on the 28th day and decreased on the 42nd day in the liver and kidney. Fe contents decreased in the heart and liver. Fe contents increased on the 28th day and decreased on the 42nd day in the spleen and kidney. Mg contents did not significantly change in these organs. Appropriate selenium contents enhanced Mn and Zn contents, which were declined by chromium. Conversely, appropriate selenium contents reduced Ca, Fe, and Cu contents, which were increased by chromium. In conclusion, the exposure of chickens to K2Cr2O7 induced changes in different trace elements, and Na2SeO3 supplementation could alleviate this condition. 相似文献
2.
Abstract: The regional distributions of the G protein β subunits (Gβ1–β5) and of the Gγ3 subunit were examined by immunohistochemical methods in the adult rat brain. In general, the Gβ and Gγ3 subunits were widely distributed throughout the brain, with most regions containing several Gβ subunits within their neuronal networks. The olfactory bulb, neocortex, hippocampus, striatum, thalamus, cerebellum, and brainstem exhibited light to intense Gβ immunostaining. Negative immunostaining was observed in cortical layer I for Gβ1 and layer IV for Gβ4. The hippocampal dentate granular and CA1–CA3 pyramidal cells displayed little or no positive immunostaining for Gβ2 or Gβ4. No anti-Gβ4 immunostaining was observed in the pars compacta of the substantia nigra or in the cerebellar granule cell layer and Purkinje cells. Immunoreactivity for Gβ1 was absent from the cerebellar molecular layer, and Gβ2 was not detected in the Purkinje cells. No positive Gγ3 immunoreactivity was observed in the lateral habenula, lateral septal nucleus, or Purkinje cells. Double-fluorescence immunostaining with anti-Gγ3 antibody and individual anti-Gβ1–β5 antibodies displayed regional selectivity with Gβ1 (cortical layers V–VI) and Gβ2 (cortical layer I). In conclusion, despite the widespread overlapping distributions of Gβ1–β5 with Gγ3, specific dimeric associations in situ were observed within discrete brain regions. 相似文献
3.
D. Innal 《Zeitschrift fur angewandte Ichthyologie》2013,29(3):685-686
This study describes the length–weight relationship (LWR) of Pseudophoxinus alii from the Yamansaz Lake, a coastal freshwater lake in Antalya, Turkey. A total of 105 specimens were obtained using a variety of nets between April 2007 and March 2008. Total lengths ranged from 3.4 to 14.3 cm. The length–weight relationship showed a positive allometric growth (b = 3.012; R2 = 0.988). The study presents the first reference on LWR for this threatened species. The results also indicate a new maximum total length not previously reported in the international literature. 相似文献
4.
Takayoshi Yamamoto Yuta Kambayashi Kohei Tsukano Tatsuo Michiue 《Development, growth & differentiation》2023,65(3):153-160
Neural tissue is derived from three precursor regions: neural plate, neural crest, and preplacodal ectoderm. These regions are determined by morphogen-mediated signaling. Morphogen distribution is generally regulated by binding to an extracellular matrix component, heparan sulfate (HS) proteoglycan. HS is modified by many enzymes, such as N-deacetyl sulfotransferase 1 (Ndst1), which is highly expressed in early development. However, functions of HS modifications in ectodermal patterning are largely unknown. In this study, we analyzed the role of Ndst1 using Xenopus embryos. We found that ndst1 was expressed in anterior neural plate and the trigeminal region at the neurula stage. ndst1 overexpression expanded the neural crest (NC) region, whereas translational inhibition reduced not only the trigeminal region, but also the adjacent NC region, especially the anterior part. At a later stage, ndst1 knocked-down embryos showed defects in cranial ganglion formation. We also found that Ndst1 activates Wnt signaling pathway at the neurula stage. Taken together, our results suggest that N-sulfonated HS accumulates Wnt ligand and activates Wnt signaling in ndst1-expressing cells, but that it inhibits signaling in non-ndst1-expressing cells, leading to proper neuroectodermal patterning. 相似文献
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6.
An association of limnic ostracodes has been discovered in the upper part of the Irbzer Formation, of Maastrichtian age, in the Moroccan Middle-Atlas. A new species is described, Gomphocythere achloujensis nov. sp. Paracandona occitanica, which is very common in terminal Cretaceous non-marine deposits of southern Europe (France, Spain), is found for the first time on the south Tethyan margin. 相似文献
7.
Mona H. Soliman Taghreed S. Alnusaire Nessreen F. Abdelbaky Aisha A. M. Alayafi Mirza Hasanuzzaman Mohamed M. Rowezak Mohamed El-Esawi Amr Elkelish 《Phyton》2020,89(3):473-486
Salt stress is one of the major abiotic stress in plants. However,
traditional approaches are not always efficient in conferring salt tolerance. Experiments were conducted to understand the role of Trichoderma spp. (T. harzianum
and T. viride) in growth, chlorophyll (Chl) synthesis, and proline accumulation of
C. pepo exposed to salinity stress. There were three salt stress (50, 100, and
150 mM NaCl) lavels and three different Trichoderma inoculation viz. T. harzianum, T. viride, and T. harzianum + T. viride. Salt stress significantly declined the
growth in terms of the shoot and root lengths; however, it was improved by the
inoculation of Trichoderma spp. C. pepo inoculated with Trichoderma exhibited
increased synthesis of pigments like chl a, chl b, carotenoids, and anthocyanins
under normal conditions. It was interesting to observe that such positive effects
were maintained under salt-stressed conditions, as reflected by the amelioration
of the salinity-mediated decline in growth, physiology and antioxidant defense.
The inoculation of Trichoderma spp. enhanced the synthesis of proline, glutathione, proteins and increased the relative water content. In addition, Trichoderma
inoculation increased membrane stability and reduced the generation of hydrogen peroxide. Therefore, Trichoderma spp. can be exploited either individually
or in combination to enhance the growth and physiology of C. pepo under saline
conditions. 相似文献
8.
Bernard Andreu Jean-Paul ColinHamid Haddoumi André Charrière 《Revue de Micropaléontologie》2003,46(4):193
Ostracode assemblages, collected in the continental “Red Beds” of the Central High Atlas, Morocco, consist of 35 species, belonging to 17 genera, four of which are new and described herein. They allow to assign the lower member of the Iouaridène formation to the Upper Jurassic (?)-Upper Hauterivian and the Jbel Sidal formation to the Upper Hauterivian-Lower Aptian. Ostracode assemblages characterize lacustrine (freshwater) and lagoonal (oligo to mesohaline) environments. On the basis of limnic and lagoonal species, faunal connections are proposed for the Barremian-Aptian between Morocco and the Iberian Peninsula. 相似文献
9.
Otolith microstructure of Oxygymnocypris stewartii collected from the Lhasa River was examined and described with regards to the early life history events. The monthly changes
in the number of microincrements on the margin of the otolith were examined to validate the approximately daily periodicity
of otolith increment formation. The microstructure of otoliths was used to detect changes in microincrement deposition patterns
corresponding with events during early life. The annuli, microincrements and checks including the hatch check, yolk absorption
check and several recurrent patterns in the otolith were described. Periodicity of the recurrent patterns was weekly, fortnightly
and monthly. Through counting the number of the microincrements, it was confirmed that the primary growth of O. stewartii was in a period of 7 or 8 months from late March to October; it was estimated that O. stewartii might hatch between April and May. 相似文献
10.
One of the three goals of the United Nations for sustainable food security is to ensure that all people have access to sufficient,
nutritionally adequate, and safe food. Decades of tin mining in the Bitsichi area of the Jos Plateau, Nigeria, have left a
legacy of polluted water supplies, impoverished agricultural land, and soil containing abnormally high levels of naturally
occurring radioactive elements. In order to ascertain the radiological food safety of the population, different crops that
constitute the major food nutritive requirements were collected directly across farmlands in the area. The activity concentrations
of 226Ra, 228Th, and 40K were determined in the food and soil samples using γ-ray spectrometry. Additionally, in situ gamma dose rate measurements
were performed on the farms using a pre-calibrated survey meter. The corresponding activity concentrations in the food crops
ranged from below detection limit (BDL) to 684.5 Bq kg−1 for 40K, from BDL to 83.5 Bq kg−1 for 226Ra, and from BDL to 89.8 Bq kg−1 for 228Th. Activity concentrations of these radionuclides were found to be lower in cereals than in tubers and vegetables. As for
the soil samples, activity concentrations of these radionuclides varied from BDL to 166.4 Bq kg−1, from 10.9 to 470.6 Bq kg−1, and from 122.7 to 2,189.5 Bq kg−1 for 40K, 226Ra, and 228Th, respectively. Average external gamma dose rates were found to vary across the farms from 0.50 ± 0.01 to 1.47 ± 0.04 μSv h−1. Due to past mining activities, the soil radioactivity in the area has been modified and the concentration level of the investigated
natural radionuclides in the food crops has also been enhanced. However, the values obtained suggest that the dose from intake
of these radionuclides by the food crops is low and that harmful health effects are not expected. 相似文献
11.
Mobile genetic elements (MGEs), also called transposable elements (TEs), represent universal components of most genomes and are intimately involved in nearly all aspects of genome organization, function and evolution. However, there is currently a gap between the fast pace of TE discovery in silico, driven by the exponential growth of comparative genomic studies, and a limited number of experimental models amenable to more traditional in vitro and in vivo studies of structural, mechanistic and regulatory properties of diverse MGEs. Experimental and computational scientists came together to bridge this gap at a recent conference, ‘Mobile Genetic Elements: in silico, in vitro, in vivo’, held at the Marine Biological Laboratory (MBL) in Woods Hole, MA, USA. 相似文献
12.
Yung-Hun Yang Eunjung Song Eun-Jung Kim Kwangwon Lee Woo-Seong Kim Sung-Soo Park Ji-Sook Hahn Byung-Gee Kim 《Applied microbiology and biotechnology》2009,82(3):501-511
NdgR (regulator for nitrogen source-dependent growth and antibiotic production), an IclR-like regulator, has been initially
identified as a binding protein to the promoters of doxorubicin biosynthetic genes in Streptomcyes peucetius by DNA affinity capture assay method. NdgR is well conserved throughout the Streptomcyes species and many other bacteria such as Mycobacteria and Corynebacteria. In Streptomcyes coelicolor, ndgR deletion mutant showed slow cell growth and defects in differentiation and enhances the production of actinorhodin (ACT)
in minimal media containing certain amino acids where wild-type strain could not produce ACT. Although deletion mutant of
ndgR showed different antibiotic production in minimal media containing Leu or Gln, it only showed reduced mRNA expression levels
of the genes involved in leucine metabolism. Neither NdgR-dependent expression of glnA nor direct binding of NdgR protein to glnA, glnII, and glnR promoters was observed. However, ScbR, which is governed by NdgR shown by gel mobility shift assay, binds to promoter of
glnR, suggesting indirect regulation of glutamine metabolism by NdgR. NdgR protein binds to intergenic region of ndgR–leuC, and scbR–scbA involved in γ-butyrolactone. Two-dimensional gel analysis has shown a global effect of ndgR deletion in protein expression, including up-regulated proteins involved in ACT synthesis and down-regulation of chaperones
such as GroEL, GroES, and DnaK. These results suggest a global regulatory role for NdgR in amino acid metabolisms, quorum
sensing, morphological changes, antibiotic production, and expression of chaperonines in S. coelicolor.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
13.
South Africa has some of the most eutrophic aquatic systems in the world, as a result of the adoption of an unnecessarily
high 1 mg l−1 phosphorus (P) standard for all water treatment works in the 1970 s. The floating aquatic macrophyte, water hyacinth (Eichhornia crassipes (Mart.) Solms (Pontederiaceae)), has taken advantage of these nutrient rich systems, becoming highly invasive and damaging.
Despite the implementation of a biological control programme in South Africa, water hyacinth remains the worst aquatic weed.
A meta-analysis of published and unpublished laboratory studies that investigated the combined effect of P and nitrogen (N)
water nutrient concentration and control agent herbivory showed that water nutrient status was more important than herbivory
in water hyacinth growth. Analysis of long-term field data collected monthly from 14 sites around South Africa between 2004
and 2005 supported these findings. Therefore the first step in any water hyacinth control programme should be to reduce the
nutrient status of the water body. 相似文献
14.
Peter J. Van Coeverden de Groot Andrea S. Putnam Peter Erb Candace Scott Don Melnick Colleen O’Ryan Peter T. Boag 《Conservation Genetics》2011,12(3):783-792
Poaching and habitat destruction across sub-Saharan Africa brought the black rhinoceros (Diceros bicornis) close to extinction. Over the past few decades, however, one of four subspecies, D. b. bicornis, has experienced a significant population increase as a consequence of its protection within Etosha National Park (ENP),
Namibia. We report here on the level and spatial distribution of black rhinoceros genetic diversity within ENP. Using nine
microsatellite loci, genetic variation was assessed from 144 individuals. Our results are consistent with the observation
of lower levels of genetic diversity in D. b. bicornis, when compared to D. b. michaeli, but greater diversity when compared to D. b. minor. We also showed that ENP’s black rhino genetic diversity is well represented in Waterberg National Park, originally founded
with ENP individuals. We found no genetic signature of a recent bottleneck in ENP, however, suggesting that the genetic diversity
within ENP has not been adversely affected by the recent severe population decline. Using Bayesian clustering methods, we
observed no significant population structure within ENP, but positive spatial genetic correlation is observed at distances
up to 25 km. This relationship exists in females but not males, suggesting reduced dispersal among females, the first evidence
of limited female dispersal or philopatry in any species of rhinoceros. 相似文献
15.
Brent R. Campos Maxfield A. Fish Gardner Jones Rebecca W. Riley Peter J. Allen Peter A. Klimley Joseph J. CechJr John T. Kelly 《Environmental Biology of Fishes》2009,85(1):3-13
Ultrasonic telemetry was used to analyze the effects of environmental variables on movement directions and movement rates
of brown smoothhounds, Mustelus henlei, in Tomales Bay, California. Ultrasonic transmitters were surgically implanted in the peritoneal cavities of one male and
five female brown smoothhounds and tracked during the period of 29 June to 15 July 2004. Coarse-scale tracking consisted of
locating all tagged individuals multiple times during a single session, while fine-scale tracking consisted of following a
single individual continuously during a session. Coarse-scale tracking suggested movement toward the inner bay with incoming
and high tides and toward the outer bay with outgoing and low tides (P = 0.01), whereas the diel cycle had no apparent effect
on their movement directions. Mean shark movement rate was 0.09 m s−1 (range: 0.01–0.34 m s−1), with diel and tidal cycles both having significant effects on their rates of movement (P = 0.02 and P < 0.01), respectively. We tracked two female sharks on a fine scale over three tracking sessions in July 2004. Both individuals
exhibited higher rates of movement during the night compared to the day (P < 0.01). While one shark’s rate of movement was not significantly affected by tidal stage, the other’s was (P < 0.001). 相似文献
16.
Hamidreza Mohammadi Mohammad Shokrzadeh Zahra Aliabadi Bamdad Riahi-Zanjani 《Mycotoxin Research》2016,32(2):85-87
The frequency and levels of aflatoxin M1 (AFM1) in pasteurized milk samples in Sari, located in Mazandaran province, Iran, were determined by enzyme immunoassay. Seventy-six samples of pasteurized milk from different retail stores were randomly collected over four seasons during the year 2015. AFM1 contamination was detected in all milk samples. The mean concentration of aflatoxin M1 was 65.8 ng/l, with a range of 11.7–106.6 ng/l. The highest AFM1 level was detected in milk samples collected during spring. Forty-six (60.53 %) samples had AFM1 levels that exceeded the maximum acceptable levels (50 ng/l) recommended by the European Union (EU). Comparison of these results with previously published data for AFM1 in milk in Iran shows that the percentage of samples exceeding the EU maximum level is consistently high over the years, indicating a general problem related to AFB1 contamination in dairy feedingstuff. 相似文献
17.
We assessed the population status of endangered lion-tailed macaques (Macaca silenus) in the rain forests of Kudremukh Forest complex (Kudremukh National Park, Someshwara Wildlife Sanctuary and Mookambika Wildlife
Sanctuary), Western Ghats, Karnataka in January 2007. We performed a census of 20 groups in Kudremukh NP, 4 groups in Someshwara
WS, and 6 groups in Mookambika WS. We estimated the population size as ca. 451 individuals in the 3 parks. The forests of Kudremukh NP and Someshwara WS are continuous, and the present finding of
24 groups in a single continuous forest confirms the existence of another significant population of lion-tailed macaques. 相似文献
18.
19.
The muck soils of the north shore of Lake Apopka, near Orlando, Florida, USA are high in organic matter, inorganic nutrients,
and water content. Ideally suited for agriculture, these soils have been exposed to a wide variety of agrochemicals. Some
of the more recalcitrant organochlorine pesticides, such as DDT and its degradation products DDD and DDE, have persisted in
the soil for over 30 years. Using the extracellular enzymes from wood rot fungi, it was demonstrated that it is possible to
substantially reduce the amount of the o,p′ and p,p′ isomers of DDT, DDD, and DDE in this soil by more than 60% in 3 weeks. A fungal species with 99% DNA homology to Nectria mariannaeae was isolated from this muck soil and identified by nucleotide sequencing. When grown under nitrogen-limited conditions, this
Nectria sp. has been shown to be comparable to Phanerochaete chrysosporium (ATCC 24725) in producing extracellular factors (or agents) that are capable of degrading these recalcitrant chlorinated
chemicals. 相似文献
20.
Chromatin from a uninucleate dinoflagellate, Crypthecodinium cohnii, a binucleate dinoflagellate, Peridinium balticum, and a chromophyte, Olisthodiscus luteus, was examined by nuclease digestion and the results were compared to those from vertebrates. Gel analysis of the products of staphylococcal (micrococcal) nuclease digestion revealed a DNA repeat unit of 220(±5) base pairs for O. luteus and 215(±5) for P. balticum. Limit digestion gave a core particle of 140 base pairs, revealing that these longer repeat sizes are due to longer linker regions. No repeating subunit structure was found upon electrophoresis of digests of C. cohnii nuclei. Examination of the DNA fragments produced by DNAse I digestion of nuclei isolated from P. balticum and O. luteus showed the same ladder of ten base multiples as seen in chromatin from other eukaryotes. Examination of the kinetics of digestion by DNAse II of Peridinium chromatin revealed less susceptibility when compared to DNAse I digestions while 70% of Olisthodiscus chromatin and 35% of C. cohnii chromatin was sensitive to DNAse II. These data, taken together with previous results from Euglena, indicate that while algal chromatin is similar to that of higher eukaryotes in regard to DNAse I and II action, it differs in that the linker DNA is longer. In addition, the Hl-like histone from O. luteus and P. balticum is located in the linker DNA as in higher eukaryotes. 相似文献