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1.
Larvae and juveniles ofLateolabrax japonicus andL. latus occurred from January to May 1986 in the shallow waters of the Shimanto estuary.L. japonicus markedly outnumberedL. latus. Distinct ecological differences were recognized in habitats and food habits between the two species:L. japonicus mainly inhabited eelgrass beds composed ofZostera nana, whileL. latus appeared evenly in both eelgrass beds and non-eelgrass habitats; the former fed on copepods and cladocerans, while the latter fed on copepods and fish larvae. From these habitat and food habit analyses, estuaries were considered to be important as a main habitat forL. japonicus, but not forL. latus. The fact that ecological differences have occurred during the early life stages was inferred to be one of the possible keys to speculate on the speciation of the two species.  相似文献   

2.
Consumption, production, and respiration of fish communities utilizing two eelgrass beds in a shallow estuarine system near Beaufort, North Carolina have been estimated for 1971–1972: annual production was 21.7 kcal/m2 in each bed with pinfish accounting for 45 and 68% of the production in the Phillips Island and Bogue Sound beds, respectively. Annual community respiration was 57.9 and 69.7 kcal/m2 in the two beds with pinfish accounting for 62.6 and 26.7% of the total in the Bogue Sound and Phillips Island beds, respectively. Estimation of the annual food energy consumed by the eelgrass fish community using the Winberg and daily ration methods gave values within 6% of each other.Energy turnover was high (2.8), and the efficiency of energy dissipation low for the two eelgrass fish communities, suggesting that the resident fish populations were adapted to the temperature extremes within the bed. High ecological efficiencies of 0.24 and 0.23 and the high overall efficiency of the eelgrass system (production/solar radiation) of 0.0051 and 0.0086% indicate that the eelgrass beds are efficient systems for converting consumed energy and solar radiation into fish.  相似文献   

3.
4.
Fusarium Wilt Suppression and Agglutinability of Pseudomonas putida   总被引:4,自引:2,他引:2       下载免费PDF全文
Mutants of Pseudomonas putida (Agg) that lack the ability to agglutinate with components present in washes of bean and cucumber roots showed limited potential to protect cucumber plants against Fusarium oxysporum f. sp. cucumerinum. However, a higher level of protection was observed against Fusarium wilt in cucumber plants coinoculated with the parental bacterium (Agg+), which was agglutinable. The Agg mutants did not colonize the roots of cucumber plants as extensively as the Agg+ parental isolate did. In competition experiments involving bean roots inoculated with a mixture of Agg+ and Agg bacteria, the Agg+ strains colonized roots to a greater extent than the Agg cells did. These data suggest that the Agg+ phenotype provides additional interactions that aid in the beneficial character of P. putida.  相似文献   

5.
We describe a large-scale random approach termed reduced representation bisulfite sequencing (RRBS) for analyzing and comparing genomic methylation patterns. BglII restriction fragments were size-selected to 500–600 bp, equipped with adapters, treated with bisulfite, PCR amplified, cloned and sequenced. We constructed RRBS libraries from murine ES cells and from ES cells lacking DNA methyltransferases Dnmt3a and 3b and with knocked-down (kd) levels of Dnmt1 (Dnmt[1kd,3a−/−,3b−/−]). Sequencing of 960 RRBS clones from Dnmt[1kd,3a−/−,3b−/−] cells generated 343 kb of non-redundant bisulfite sequence covering 66212 cytosines in the genome. All but 38 cytosines had been converted to uracil indicating a conversion rate of >99.9%. Of the remaining cytosines 35 were found in CpG and 3 in CpT dinucleotides. Non-CpG methylation was >250-fold reduced compared with wild-type ES cells, consistent with a role for Dnmt3a and/or Dnmt3b in CpA and CpT methylation. Closer inspection revealed neither a consensus sequence around the methylated sites nor evidence for clustering of residual methylation in the genome. Our findings indicate random loss rather than specific maintenance of methylation in Dnmt[1kd,3a−/−,3b−/−] cells. Near-complete bisulfite conversion and largely unbiased representation of RRBS libraries suggest that random shotgun bisulfite sequencing can be scaled to a genome-wide approach.  相似文献   

6.
Poly(ADP-ribose) glycohydrolase (PARG) is the primary enzyme responsible for the degradation of poly(ADP-ribose). PARG dysfunction sensitizes cells to alkylating agents and induces cell death; however, the details of this effect have not been fully elucidated. Here, we investigated the mechanism by which PARG deficiency leads to cell death in different cell types using methylmethanesulfonate (MMS), an alkylating agent, and Parg−/− mouse ES cells and human cancer cell lines. Parg−/− mouse ES cells showed increased levels of γ-H2AX, a marker of DNA double strand breaks (DSBs), accumulation of poly(ADP-ribose), p53 network activation, and S-phase arrest. Early apoptosis was enhanced in Parg−/− mouse ES cells. Parg−/− ES cells predominantly underwent caspase-dependent apoptosis. PARG was then knocked down in a p53-defective cell line, MIAPaCa2 cells, a human pancreatic cancer cell line. MIAPaCa2 cells were sensitized to MMS by PARG knockdown. Enhanced necrotic cell death was induced in MIAPaCa2 cells after augmenting γ-H2AX levels and S-phase arrest. Taken together, these data suggest that DSB repair defect causing S-phase arrest, but p53 status was not important for sensitization to alkylation DNA damage by PARG dysfunction, whereas the cell death pathway is dependent on the cell type. This study demonstrates that functional inhibition of PARG may be useful for sensitizing at least particular cancer cells to alkylating agents.  相似文献   

7.
The initial discovery in May 2009 of eelgrass (Zostera marina) seeds in fecal samples of wild-caught northern diamondback terrapins (Malaclemys terrapin terrapin) was the first field evidence of eelgrass seed ingestion in this species. This finding suggested the potential of terrapins as seed dispersers in eelgrass beds, which we sampled for two additional years (2010 and 2011). Seeds were only found in feces of terrapins captured prior to June 8 in all three years, coinciding with eelgrass seed maturation and release. Numbers of seeds in terrapin feces varied annually and decreased greatly in 2011 after an eelgrass die off in late 2010. The condition of seeds in terrapin feces was viable-mature, germinated, damaged, or immature. Of terrapins captured during time of seed release, 97% were males and juvenile females, both of which had head widths <30 mm. The fraction of individuals with ingested seeds was 33% for males, 35% for small females, and only 6% for large (mature) females. Probability of seed ingestion decreased exponentially with increasing terrapin head width; only males and small females (head width <30 mm) were likely to be vectors of seed dispersal. The characteristic that diamondback terrapins have well-defined home ranges allowed us to estimate the number of terrapins potentially dispersing eelgrass seeds annually. In seagrass beds of the Goodwin Islands region (lower York River, Virginia), there were 559 to 799 terrapins, which could disperse between 1,341 and 1,677 eelgrass seeds annually. These would represent a small proportion of total seed production within a single seagrass bed. However, based on probable home range distances, terrapins can easily traverse eelgrass meadow boundaries, thereby dispersing seeds beyond the bed of origin. Given the relatively short dispersion distance of eelgrass seeds, the diamondback terrapin may be a major source of inter-bed seed dispersal and genetic diversity.  相似文献   

8.
The underlying mechanism for the establishment and maintenance of differential DNA methylation in imprinted genes is largely unknown. Previous studies using Dnmt1 knock-out embryonic stem (ES) cells demonstrated that, although re-expression of DNMT1 restored DNA methylation in the non-imprinted regions, the methylation patterns of imprinted genes could be restored only through germ line passage. Knock-out of Uhrf1, an accessory factor essential for DNMT1-mediated DNA methylation, in mouse ES cells also led to impaired global DNA methylation and loss of genomic imprinting. Here, we demonstrate that, although re-expression of UHRF1 in Uhrf1−/− ES cells restored DNA methylation for the bulk genome but not for most of the imprinted genes, it did rescue DNA methylation for the imprinted H19, Nnat, and Dlk1 genes. Analysis of histone modifications at the differential methylated regions of the imprinted genes by ChIP assays revealed that for the imprinted genes whose DNA methylation could be restored upon re-expression of UHRF1, the active histone markers (especially H3K4me3) were maintained at considerably low levels, and low levels were maintained even in Uhrf1−/− ES cells. In contrast, for the imprinted genes whose DNA methylation could not be restored upon UHRF1 re-expression, the active histone markers (especially H3K4me3) were relatively high and became even higher in Uhrf1−/− ES cells. Our study thus supports a role for histone modifications in determining the establishment of imprinting-related DNA methylation and demonstrates that mouse ES cells can be a valuable model for mechanistic study of the establishment and maintenance of differential DNA methylation in imprinted genes.  相似文献   

9.
The effects of water stress on pressure differences and 14C-assimilate translocation in sieve tubes of squirting cucumber Ecballium elaterium A. Rich were studied. Water stress was induced by transfer of plants from culture solution to a polyethylene glycol 6,000 solution having an osmotic potential of −18.2 atm. Sieve tube turgor, turgor differences between source and sink, and translocation rate were decreased. After 260 minutes of translocation, only 19% of the total fixed 14CO2 had moved out of the leaf, compared to the control value of 62% after the same period of time. The results suggest that water stress slows translocation by lowering sieve tube turgor differences, which are essential for the pressure flow mechanism of conduction.  相似文献   

10.
The assessment of the status of eelgrass (Zostera marina) beds at the bay-scale in turbid, shallow estuaries is problematic. The bay-scale assessment (i.e., tens of km) of eelgrass beds usually involves remote sensing methods such as aerial photography or satellite imagery. These methods can fail if the water column is turbid, as is the case for many shallow estuaries on Canada’s eastern seaboard. A novel towfish package was developed for the bay-scale assessment of eelgrass beds irrespective of water column turbidity. The towfish consisted of an underwater video camera with scaling lasers, sidescan sonar and a transponder-based positioning system. The towfish was deployed along predetermined transects in three northern New Brunswick estuaries. Maps were created of eelgrass cover and health (epiphyte load) and ancillary bottom features such as benthic algal growth, bacterial mats (Beggiatoa) and oysters. All three estuaries had accumulations of material reminiscent of the oomycete Leptomitus, although it was not positively identified in our study. Tabusintac held the most extensive eelgrass beds of the best health. Cocagne had the lowest scores for eelgrass health, while Bouctouche was slightly better. The towfish method proved to be cost effective and useful for the bay-scale assessment of eelgrass beds to sub-meter precision in real time.  相似文献   

11.

Background

CXCL14 is a chemoattractant for macrophages and immature dendritic cells. We recently reported that CXCL14-deficient (CXCL14 −/−) female mice in the mixed background are protected from obesity-induced hyperglycemia and insulin resistance. The decreased macrophage infiltration into visceral adipose tissues and the increased insulin sensitivity of skeletal muscle contributed to these phenotypes.

Methodology/Principal Findings

In this study, we performed a comprehensive study for the body weight control of CXCL14 −/− mice in the C57BL/6 background. We show that both male and female CXCL14 −/− mice have a 7–11% lower body weight compared to CXCL14 +/− and CXCL14 +/+ mice in adulthood. This is mainly caused by decreased food intake, and not by increased energy expenditure or locomotor activity. Reduced body weight resulting from the CXCL14 deficiency was more pronounced in double mutant CXCL14−/− ob/ob and CXCL14 −/−Ay mice. In the case of CXCL14 −/−Ay mice, oxygen consumption was increased compared to CXCL14 +/−Ay mice, in addition to the reduced food intake. In CXCL14 −/− mice, fasting-induced up-regulation of Npy and Agrp mRNAs in the hypothalamus was blunted. As intracerebroventricular injection of recombinant CXCL14 did not change the food intake of CXCL14 −/− mice, CXCL14 could indirectly regulate appetite. Intriguingly, the food intake of CXCL14 −/− mice was significantly repressed when mice were transferred to a novel environment.

Conclusions/Significance

We demonstrated that CXCL14 is involved in the body weight control leading to the fully obese phenotype in leptin-deficient or Ay mutant mice. In addition, we obtained evidence indicating that CXCL14 may play an important role in central nervous system regulation of feeding behavior.  相似文献   

12.
We have used gene disruption to isolate two talin (−/−) ES cell mutants that contain no intact talin. The undifferentiated cells (a) were unable to spread on gelatin or laminin and grew as rounded colonies, although they were able to spread on fibronectin (b) showed reduced adhesion to laminin, but not fibronectin (c) expressed much reduced levels of β1 integrin, although levels of α5 and αV were wild-type (d) were less polarized with increased membrane protrusions compared with a vinculin (−/−) ES cell mutant (e) were unable to assemble vinculin or paxillin-containing focal adhesions or actin stress fibers on fibronectin, whereas vinculin (−/−) ES cells were able to assemble talin-containing focal adhesions. Both talin (−/−) ES cell mutants formed embryoid bodies, but differentiation was restricted to two morphologically distinct cell types. Interestingly, these differentiated talin (−/−) ES cells were able to spread and form focal adhesion-like structures containing vinculin and paxillin on fibronectin. Moreover, the levels of the β1 integrin subunit were comparable to those in wild-type ES cells. We conclude that talin is essential for β1 integrin expression and focal adhesion assembly in undifferentiated ES cells, but that a subset of differentiated cells are talin independent for both characteristics.  相似文献   

13.
Eelgrass beds in coastal waters of China have declined substantially over the past 30 years. In this study, a simple new transplanting technique was developed for eelgrass (Zostera marina L.) restoration. To assist in anchoring single shoots, several rhizomes of rooted shoots were bound to a small elongate stone (50–150 g) with biodegradable thread (cotton or hemp), and then the bound packet was buried at an angle in the sediments at a depth of 2–4 cm. This stone anchoring method was used to transplant eelgrass in early November 2009 and late May 2010 in Huiquan Bay, Qingdao. The method led to high success. Three month survivorship of the transplanted shoots at the two transplant sites was >95%. From April 20 to November 19, 2012, the following characteristics of the 2009 and 2010 transplanted eelgrass beds were monitored: morphological changes, shoot density, shoot height, leaf biomass, and sediment particle size. Results showed that the sexual reproduction period of the planted eelgrass was from April to August, and vegetative reproduction reached its peak in autumn. Maximum shoot height and biomass were observed in June and July. After becoming established, the transplanted eelgrass beds were statistically equal to natural eelgrass beds nearby in terms of shoot height, biomass, and seasonal variations. This indicates that the transplant technique is effective for eelgrass restoration in coastal waters.  相似文献   

14.
The reestablishment of seagrass vegetation is a vital part of recovering coastal marine ecosystem services. Historically the Hinase area was a famous for the fishing by coastal pound netting in eelgrass beds, but this practice was progressively displaced with oyster farming due to an enormous decline in seagrass vegetation. For several decades, the local fishers' cooperative has worked to restore eelgrass beds by a seeding method. Through these efforts, seagrass vegetation in their fishing area has increased to about half of their previous area. This study examined the effect of long-term seeding by fishers on the recovery of eelgrass beds in the Hinase area, based on analysis of eelgrass genetic structure using microsatellite markers. Specimens for the DNA analysis were collected from each of all eelgrass meadows that the fishers conducted sowing eelgrass seeds as well as from the source sites where they collected the seeds. The results found that restored beds in the study area have high genetic diversity comparable to natural ones. The multiple regression analysis revealed that a combined model of seedling intensity and geographic distance (R2 = .457) better explained genetic structure across our sampling sites than models of seedling intensity (R2 = .092) or geographic distance only (R2 = .344). This supports that the eelgrass seeds they sowed did not disturb the genetic structure but rather supplemented natural dispersal, suggesting that the fishers' seeding did not develop nonnatural seagrass meadows but certainly contributed to the recovery of natural seagrass meadows.  相似文献   

15.

Background

Perinatal common mental disorders (PCMDs) are a major cause of disability among women. Psychosocial interventions are one approach to reduce the burden of PCMDs. Working with care providers who are not mental health specialists, in the community or in antenatal health care facilities, can expand access to these interventions in low-resource settings. We assessed effects of such interventions compared to usual perinatal care, as well as effects of interventions based on intervention type, delivery method, and timing.

Methods and Findings

We conducted a systematic review, meta-analysis, and meta-regression. We searched databases including Embase and the Global Health Library (up to 7 July 2013) for randomized and non-randomized trials of psychosocial interventions delivered by non-specialist mental health care providers in community settings and antenatal health care facilities in low- and middle-income countries. We pooled outcomes from ten trials for 18,738 participants. Interventions led to an overall reduction in PCMDs compared to usual care when using continuous data for PCMD symptomatology (effect size [ES] −0.34; 95% CI −0.53, −0.16) and binary categorizations for presence or absence of PCMDs (odds ratio 0.59; 95% CI 0.26, 0.92). We found a significantly larger ES for psychological interventions (three studies; ES −0.46; 95% CI −0.58, −0.33) than for health promotion interventions (seven studies; ES −0.15; 95% CI −0.27, −0.02). Both individual (five studies; ES −0.18; 95% CI −0.34, −0.01) and group (three studies; ES −0.48; 95% CI −0.85, −0.11) interventions were effective compared to usual care, though delivery method was not associated with ES (meta-regression β coefficient −0.11; 95% CI −0.36, 0.14). Combined group and individual interventions (based on two studies) had no benefit compared to usual care, nor did interventions restricted to pregnancy (three studies). Intervention timing was not associated with ES (β 0.16; 95% CI −0.16, 0.49). The small number of trials and heterogeneity of interventions limit our findings.

Conclusions

Psychosocial interventions delivered by non-specialists are beneficial for PCMDs, especially psychological interventions. Research is needed on interventions in low-income countries, treatment versus preventive approaches, and cost-effectiveness. Please see later in the article for the Editors'' Summary  相似文献   

16.
A total of 343 larval and juvenile Lateolabrax latus (9.2–27.0 mm TL) was collected with a small seine in surf zones of Tosa Bay. They are very similar in general morphology to those of the closely related L. japonicus, but can be distinguished from them by the distribution pattern of melanophores on the tail, head spination, proportion of head length to standard length and the 15 or 16 dorsal fin soft-rays. They occurred in surf zones of Tosa Bay from early January to middle May, being most abundant in middle April. Temperatures and salinities of waters where any number of them were collected ranged from 12.2 to 24.0°C and from 23.7 to 34.5%, respectively. Larval and juvenile L. latus have not been reported so far in coastal and shallow waters, and eelgrass beds of southern Japan. It may be possible that they have been confounded with those of L. japonicus. Their occurrence seems to be limited in extremely shallow waters such as surf zones.  相似文献   

17.
18.
A total of 54 postlarval, 12 juvenile and six young Lates japonicus were collected in the Shimanto estuary from August 1985 to January 1987. The larvae (4.3–7.6 mm SL) and juveniles (8.1–28.0 mm SL) occurred only in areas with eelgrass beds from late July to middle August. Temperatures and salinities at waters where any number of them were collected ranged from 27.8 to 31.9°C and from 2.8 to 18.2%, respectively. The larvae are very similar in general morphology to those of Mugilidae and some of Gobiidae, but are distinguished from others by the spines of preopercle, position of the anus and pigmentation patterns in the posterior part of body.  相似文献   

19.
Environmental studies of the human-pathogenic bacterium Campylobacter jejuni have focused on linking distributions with potential sources. However, in aquatic ecosystems, the abundance of C. jejuni may also be regulated by predation. We examine the potential for grazing by the freshwater planktonic crustacean Daphnia carinata to reduce the survival of C. jejuni. We use a system for measuring grazing and clearance rates of D. carinata on bacteria and demonstrate that D. carinata can graze C. jejuni cells at a rate of 7% individual−1 h−1 under simulated natural conditions in the presence of an algal food source. We show that passage of C. jejuni through the Daphnia gut and incorporation into fecal material effectively reduces survival of C. jejuni. This is the first evidence to suggest that grazing by planktonic organisms can reduce the abundance of C. jejuni in natural waters. Biomanipulation of planktonic food webs to enhance Daphnia densities offers potential for reducing microbial pathogen densities in drinking water reservoirs and recreational water bodies, thereby reducing the risk of contracting water-borne disease.  相似文献   

20.
Submicronic particles released from fungal cultures have been suggested to be additional sources of personal exposure in mold-contaminated buildings. In vitro generation of these particles has been studied with particle counters, eventually supplemented by autofluorescence, that recognize fragments by size and discriminate biotic from abiotic particles. However, the fungal origin of submicronic particles remains unclear. In this study, submicronic fungal particles derived from Aspergillus fumigatus, A. versicolor, and Penicillium chrysogenum cultures grown on agar and gypsum board were aerosolized and enumerated using field emission scanning electron microscopy (FESEM). A novel bioaerosol generator and a fungal spores source strength tester were compared at 12 and 20 liters min−1 airflow. The overall median numbers of aerosolized submicronic particles were 2 × 105 cm−2, 2.6 × 103 cm−2, and 0.9 × 103 cm−2 for A. fumigatus, A. versicolor, and P. chrysogenum, respectively. A. fumigatus released significantly (P < 0.001) more particles than A. versicolor and P. chrysogenum. The ratios of submicronic fragments to larger particles, regardless of media type, were 1:3, 5:1, and 1:2 for A. fumigatus, A. versicolor, and P. chrysogenum, respectively. Spore fragments identified by the presence of rodlets amounted to 13%, 2%, and 0% of the submicronic particles released from A. fumigatus, A. versicolor, and P. chrysogenum, respectively. Submicronic particles with and without rodlets were also aerosolized from cultures grown on cellophane-covered media, indirectly confirming their fungal origin. Both hyphae and conidia could fragment into submicronic particles and aerosolize in vitro. These findings further highlight the potential contribution of fungal fragments to personal fungal exposure.  相似文献   

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