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1.
研究了转mtlD/gutD双价基因稻米对大鼠的性腺毒性。通过对大鼠90 d喂养观察及对各组动物的睾丸和卵巢进行组织切片检查,未见有意义的病理改变。比较雌性大鼠的性成熟、雄性大鼠的精子畸变率及雌雄大鼠的性激素水平,各实验组与对照组均无显著差异(P＞0.05)。结果初步表明用转mtlD/gutD双价基因水稻秀水11品系T18 7 8 1稻米喂养大鼠90 d对大鼠性腺器官的结构和功能无明显影响。  相似文献   

2.
Molecular Genetics of Rice Root Development   总被引：1，自引：0，他引：1  
Plant roots have a large range of functions, including acquisition of water and nutrients, as well as structural support. Dissecting the genetic and molecular mechanisms controlling rice root development is critical for the development of new rice ideotypes that are better adapted to adverse conditions and for the production of sustainably achieved rice yield potential. Most knowledge regarding the gene networks involved in root development has been accumulated in the model dicotyledon plant species Arabidopsis thaliana. Rice, the model monocotyledon species, presents several singularities compared to A. thaliana, including a root architecture characterized by a fibrous root system comprising five types of embryonic and postembryonic roots. The anatomy and morphology of the rice root system, which is typical for a cereal, differs from that of A. thaliana, for instance, by the presence of a lysigenous cortex and additional cell layers compared to the dicotyledon model. Moreover, the structure and functions of the root apical meristem (RAM) of rice are distinct from those of A. thaliana. Recently, several rice root mutants have been identified via forward or reverse genetics, and these will aid in forming hypothesis to characterize either the divergence or conservation of genetic pathways relative to A. thaliana. Furthermore, these mutants will help to identify key genes in rice roots that may be missing in A. thaliana. This review summarizes both classical and recent data concerning the molecular genetics of rice root development, including root anatomy and morphology, RAM structure, RAM patterning, and root mutants.  相似文献   

3.
The testicular histology of the lizard, Uromastyx aegyptius microlepis were varied considerably during hibernation and activity periods, reaching maximum values in summer. The onset of winter induces testicular regression, reduced testis size, testis diameter, diameter and epithelial height of the seminiferous tubules and epididymal epithelial height. Animals exhibit testicular recrudescence during late winter (February and March) and maximum testicular volume occurred during June. The period of maximal testicular volume was positively correlated with increasing ambient temperature. The summer season induces the testicular activity in contrast with the winter season in which the activity decreased and the testes were collapsed. Spermatocytogenesis is active in early spring and the major portion of the seminiferous epithelium comprises spermatids in various stages of maturation and their luminae were filled with spermatozoa. The size of the interstitial cells is direct correlated with changes occurring in epididymis and seminiferous epithelium. Most interstitial cell nuclei show clear regression when spermatocytogenesis were diminishes.  相似文献   

4.

Background

Parasites that manipulate host behavior can provide prominent examples of extended phenotypes: parasite genomes controlling host behavior. Here we focus on one of the most dramatic examples of behavioral manipulation, the death grip of ants infected by Ophiocordyceps fungi. We studied the interaction between O. unilateralis s.l. and its host ant Camponotus leonardi in a Thai rainforest, where infected ants descend from their canopy nests down to understory vegetation to bite into abaxial leaf veins before dying. Host mortality is concentrated in patches (graveyards) where ants die on sapling leaves ca. 25 cm above the soil surface where conditions for parasite development are optimal. Here we address whether the sequence of ant behaviors leading to the final death grip can also be interpreted as parasite adaptations and describe some of the morphological changes inside the heads of infected workers that mediate the expression of the death grip phenotype.

Results

We found that infected ants behave as zombies and display predictable stereotypical behaviors of random rather than directional walking, and of repeated convulsions that make them fall down and thus precludes returning to the canopy. Transitions from erratic wandering to death grips on a leaf vein were abrupt and synchronized around solar noon. We show that the mandibles of ants penetrate deeply into vein tissue and that this is accompanied by extensive atrophy of the mandibular muscles. This lock-jaw means the ant will remain attached to the leaf after death. We further present histological data to show that a high density of single celled stages of the parasite within the head capsule of dying ants are likely to be responsible for this muscular atrophy.

Conclusions

Extended phenotypes in ants induced by fungal infections are a complex example of behavioral manipulation requiring coordinated changes of host behavior and morphology. Future work should address the genetic basis of such extended phenotypes.  相似文献   

5.

Objective

To describe clinical and histological features observed in the setting of an unusual complex translocation involving three autosomes (9, 13, and 14) identified in an otherwise healthy male referred for infertility consultation.

Materials and methods

The patient was age 30 and no family history was available (adopted). Total azoospermia was confirmed on multiple semen analyses. Peripheral karyotype showed a 46,XY t(9;13;14)(p22:q21.2;p13) genotype; no Y-chromosome microdeletions were identified. Cystic fibrosis screening was negative. Bilateral testis biopsy revealed uniform maturation arrest and peritubular fibrosis.

Results

Formal genetic counseling was obtained and the extant literature reviewed with the couple. Given the low probability of obtaining sperm on testicular biopsy, as well as the high risk of any retrieved sperm having an unbalanced genetic rearrangement, the couple elected to proceed with fertility treatment using anonymous donor sperm for insemination.

Conclusion

Although genes mapped to the Y-chromosome have been established as critical to normal testicular development and spermatogenesis, certain autosomal genes are now also recognized as important in these processes. Here we present clinical evidence to support the Luciani-Guo hypothesis (first advanced in 1984 and refined in 2002), which predicts severe spermatogenic impairment with aberrations involving chromosomes 9, 13, and/or 14, independent of Y-chromosome status. Additional study including fluorescent in situ hybridization and molecular analysis of specific chromosomal regions is needed to characterize more fully the contribution(s) of these autosomes to male testicular development and spermatogenesis.
  相似文献   

6.
黄意欢 《茶叶科学》1991,11(1):29-34
本文以鳛水大树茶和福鼎大白茶为材料,对茶树茎的阶段发育异质性问题,从植物解剖学角度进行了较系统的研究,并对共外部形态特征、特性进行了观察测定。结果表明,茶树茎的异质性现象是普遍存在的,两个品种不同部位的芽和茎的解剖结构是有差异的,低位枝上的顶端分生组织、伸长区及茎成熟区组织的分化程度均较高位枝的发达,为典型的“幼年型”。但不同部位间的差异显著水平有别。本文还对茎的阶段发育及生产中的有关问题进行了讨论。  相似文献   

7.
切除顶芽和叶片的油菜带节枝段,在含BA1mg/l和NAA0.1mg/l的MS培养基上,其腋生分生组织通常发育成三种类型腋生枝:正常的、半透明的或玻璃化的。顶芽和叶片的存在抑制玻璃腋生枝形成,叶片对腋生分生组织的正常发育也具有一定的作用。玻璃腋生枝的形成与培养基中的细胞分裂素有关。腋生分生组织发育成一定大小的正常腋芽后,不能形成玻璃腋生枝。  相似文献   

8.
Exploration into reproductive quality in honey bees (Apis mellifera Linneaus (Hymenoptera: Apidae) largely focuses on factors that affect queens, with drones primarily being considered insofar as they pass on effects of environmental stressors to the queen and subsequent offspring. In those studies that consider drone quality explicitly, a primary focus has been on the dimorphic nature of drones laid in worker cells (either through rare queen error or worker reproduction) as compared to drones laid by the queen in the slightly larger drone cells. The implication from these studies is that that there exists a bimodality of drone morphological quality that is related to reproductive quality and competitive ability during mating. Our study quantifies the presence of such small drones in commercial populations, finding that rates of ‘low-quality’ drones are far higher than theoretically predicted under optimum conditions. Observations from commercial colonies also show significant inter-colony variation among the size and fecundity of drones produced, prompting speculation as to the mechanisms inducing such variation and the potential use of drone-quality variation for the colony- or apiary-level exposure to nutrition, agrichemical, or parasitic stressors.  相似文献   

9.
Marine-derived sulfated polysaccharides have been shown to possess certain anti-virus, anti-tumor, anti-inflammatory and anti-coagulant activities. However, the in vivo immunomodulatory effects of marine-derived pure compounds have been less well characterized. In this study, we investigated the effect of ascophyllan, a sulfated polysaccharide purified from Ascophyllum nodosum, on the maturation of mouse dendritic cells (DCs) in vitro and in vivo. Ascophyllan induced up-regulation of co-stimulatory molecules and production of pro-inflammatory cytokines in bone marrow-derived DCs (BMDCs). Moreover, in vivo administration of ascophyllan promotes up-regulation of CD40, CD80, CD86, MHC class I and MHC class II and production of IL-6, IL-12 and TNF-α in spleen cDCs. Interestingly, ascophyllan induced a higher degree of co-stimulatory molecule up-regulation and pro-inflammatory cytokine production than fucoidan, a marine-derived polysaccharide with well-defined effect for promoting DC maturation. Ascophyllan also promoted the generation of IFN-γ-producing Th1 and Tc1 cells in the presence of DCs in an IL-12-dependent manner. Finally, myeloid differentiation primary response 88 (MyD88) signaling pathway was essential for DC maturation induced by ascophyllan. Taken together, these results demonstrate that ascophyllan induces DC maturation, and consequently enhances Th1 and Tc1 responses in vivo. This knowledge could facilitate the development of novel therapeutic strategies to combat infectious diseases and cancer.  相似文献   

10.
Acid invertase plays an important role in plants by hydrolyzing sucrose. Compounds exhibiting cytokinin activity were examined for their effects on acid invertase activity at three tuberization stages of potato,Solanum tuberosum L. Single nodal segments from the cultivar Atlantic were cultured on Murashige and Skoog (MS) medium with 6% sucrose and maintained under a 16-hr photoperiod. Media were supplemented with either 2 mg kinetin/1, 0.1 mg thidiazuron/1,1.0 mg AC243, 654/1 (a benzyl nitroguanidine), or 0.1 mg AC239, 604/1 (a phenyl nitroguanidine). Basal acid invertase activity was measured in stolon segments at three morphologically distinct tuberization stages: (1) “hook,” (2) “swelling,” and (3) “initiation.” The onset of tuber initiation was significantly advanced by kinetin and thidiazuron compared to controls. Stolons elongated during the hook and swelling stages until tubers were initiated. Basal acid invertase activity in stolons cultured on control medium significantly increased from hook stage to swelling stage and then decreased slightly when tubers were initiated. At the hook stage, highest basal acid invertase activity occurred when the segments were treated with kinetin and thidiazuron. Kinetin and thidiazuron induced basal acid invertase activity significantly decreased following the hook stage to tuber initiation. Basal acid invertase activity were significantly lower in stolons treated with nitroguanidines than the control activity following the hook stage of development. During the swelling and tuber initiation stages, nitroguanidines-treated segments showed reduction in basal acid invertase activity similar to segments treated with kinetin and thidiazuron treatments. Tuber initiation was preceded by a stimulation of basal acid invertase activity followed by a decrease prior to tuber initiation. Kinetin and thidiazuron stimulated enzyme activity early in the growth of stolons which may have resulted in faster stolon growth and in earlier tuber initiation. The two nitroguanidines, although able to mimic many cytokinin effects in bioassays, did not seem to act in the same way as kinetin.  相似文献   

11.
Gibberellins (GAs) are involved in internode elongation and other important processes such as seed germination, flowering, maturation, tuberization, and tuber dormancy. The discovery of GA-deficient mutants enabled further study of the role of these hormones in many plant processes. GA-deficient mutants lack the ability to produce adequate amounts of gibberellin for normal growth, resulting in a rosette type growth and short internodes. Thega 1 mutant allele was introduced into various genetic backgrounds including differentSolanum species and ploidies. Diploid GA-deficient genotypes were obtained by crossing haploidSolanum tuberosum ssp.andigena withSolanum chacoense. The progeny was then bulked and intermated to produce F2 individuals. Tetraploid GA-deficient genotypes were obtained by crossingS. tuberosum ssp.andigena withSolanum sucrense and withSolanum gourlayi. The two resulting progenies were then bulked and intermated. Diploid and tetraploid GA-deficient genotypes were grown on MS media containing different levels of gibberellin (GA3). Plant height and visual observations were made as a way to assess the response of these genotypes to GA3. Concentration of 0.1 µM GA3 and lower failed to restore normal plant height in both diploid and tetraploid genotypes. Normal plant height was restored in most of the GA-deficient genotypes when concentrations between 0.8 and 1.2 µM GA3 were used. We found some important differences between these genotypes: (1) the level of GA3 to restore normal plant height varies among the GA-deficient genotypes, some needed more GA3 than others to grow normally; (2) the time to respond to the presence of GA3 in the media differs between the GA-deficient genotypes, (3) tetraploid genotypes exhibited normal growth and internode length in response to GA3, while diploid genotypes tended to show a rosette-type growth at the apical end. These results suggest thatga 1 mutants can be affected by a series of modifier genes and/or iso-alleles. The importance of variable response to GA among dwarf individuals is two fold: (1) experiments measuring GA response should choose and clonally multiply one genotype to ensure uniform optimal response to GA application; and (2) variation betweenga 1 mutant phenotypes could be used to characterize GA-response modifier genes.  相似文献   

12.
The maturation of potato (Solanum tuberosum L.) tuber native periderm and wound periderm, which develops to replace the native periderm when it is damaged, are agriculturally important processes that are poorly understood. While both types of periderm form from a phellogen layer that serves as a lateral meristem, there has been little research done on comparing the biochemical processes and steps involved in the maturation of the two types of periderm. Here, we use immunological techniques to compare some of the cell wall changes during wound and native periderm maturation. Consistent with our recent work on native periderm, we demonstrate that toluidine blue O is also useful for distinguishing between suberized and non-suberized cells in wound periderm. More importantly, we use the immunological probes JIM5 and JIM7 to show that there is no increase in either un-esterified or esterified homogalacturonan pectin epitopes in phellogen walls accompanying wound periderm maturation. In contrast, as we previously described, native periderm maturation and resistance to excoriation (skinning) is accompanied by an increase in relatively un-esterified and esterified homogalacturonan pectin epitopes in the walls of phellogen cells. These results demonstrate that the biochemical processes responsible for maturation and resistance to excoriation differ between native and wound periderm. This dissimilarity between wound and native periderm maturation demonstrates the potential limitations in applying the wound periderm model to research on native periderm.  相似文献   

13.
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14.
The high growth-stimulating effect of plant extract has urged the plant biotechnologists to use natural supplements in the culture media instead of synthetic phytohormones. We advocated the effect of sprouted sorghum extract(SSE) on emergence, in vitro acclimatization, and genetic fidelity in coleoptile derived callus of indica rice variety ADT36. The use of SSE with Murashige Skoog medium efficiently acclimatized the root and shoot apical systems. A higher mat and seminal roots(3.4 g biomass) with an efficient shoot primordium elongation were observed with an increase in the concentration of SSE. Seeds treated with SSE medium showed higher germination and earlier coleoptile maturation about 48 h compared to untreated seeds, and there was a higher expression of e EF-1α with an increase in coleoptile length. B5 medium was effective on inducing embryogenic and nodular callus from 3-day-old coleoptile with 3.0 mg/L 2,4-dichlorophenoxyacetic acid and further proliferated effectively with 0.8 mg/L kinetin with a fresh weight of 180 mg. Highly significant regeneration was observed with combination of 2.5 mg/L 6-benzylamino purine and 3.0 mg/L α-naphthaleneacetic acid. The metabolic and genetic profiles of in vitro and directly cultivated plants were the same, examined through Fourier-transform infrared spectroscopy, random amplified polymorphic DNA(RAPD), inter-simple sequence repeat(ISSR) and R-ISSR(combination of RAPD and ISSR) markers, respectively, and thus confirming the significant efficacy of the SSE incorporated medium. Disarmed T-DNA was transformed to coleoptile derived callus through Agrobacterium tumefaciens LBA4404 and confirmed by GUS assay. The T-DNA integration was confirmed by DNA blot analysis using DNA from transient GUS-expressed explants. Thus, SSE can be used as a natural and organic supplement for organogenesis and efficient acclimatizations of shoot and root apical meristems in regenerated plants.  相似文献   

15.
The main aim of this study was to determine the changes in free sulphydryl content during postharvest wheat and flour maturation. The content of free sulphydryl groups was determined from wet gluten over 50 days of wheat postharvest maturation and over 14 days of flour maturation by varying incubation temperatures (30 and 37 °C) and incubation times (0, 45, 90 and 135 min). The amount of free sulphydryl groups increased during postharvest wheat and flour maturation as well as with the increase in temperature and gluten incubation time. The additional aim of this study was to find the interrelation between the content of free sulphydryl groups and selected parameters of technological quality by means of Principal Component Analysis. During wheat/flour maturation, the strengthening of protein structure was observed manifested by the increase in gluten index and Mixolab protein network weakening (C2), and changes in dough resistance as well. The incubation temperature of 37 °C affected the weakening of protein structure manifested by the decrease in gluten index and resistance, and increase in extensibility. Strong differentiation of examined varieties in terms of selected quality indicators was observed upon pre-defined maturation period, probably due to the expression of their intrinsic properties.  相似文献   

16.
Roots on potato tubers and stolons displayed the normal root anatomy which consisted of a central vascular cylinder surrounded by endodermis with Casparian strips, the cortex and epidermis. Tuber roots appear to initiate from the parenchyma cells adjacent to the vascular tissue. Shoot tips were similar to normal apical meristems. These observations support our research demonstrating the growth of functional roots from potato tubers and stolons.  相似文献   

17.
The main aim of this study was to determine the changes in free sulphydryl content during postharvest wheat and flour maturation. The content of free sulphydryl groups was determined from wet gluten over 50 days of wheat postharvest maturation and over 14 days of flour maturation by varying incubation temperatures (30 and 37 °C) and incubation times (0, 45, 90 and 135 min). The amount of free sulphydryl groups increased during postharvest wheat and flour maturation as well as with the increase in temperature and gluten incubation time. The additional aim of this study was to find the interrelation between the content of free sulphydryl groups and selected parameters of technological quality by means of Principal Component Analysis. During wheat/flour maturation, the strengthening of protein structure was observed manifested by the increase in gluten index and Mixolab protein network weakening (C2), and changes in dough resistance as well. The incubation temperature of 37 °C affected the weakening of protein structure manifested by the decrease in gluten index and resistance, and increase in extensibility. Strong differentiation of examined varieties in terms of selected quality indicators was observed upon pre-defined maturation period, probably due to the expression of their intrinsic properties.  相似文献   

18.
Wild evening primrose species (Oenothera spp.) native to Argentina, have been suggested as a new crop for irrigated valleys of semi-arid Patagonia. This paper describes patterns of biomass allocation, morphological traits related to stress-tolerance and seed-yield in four species of Oenothera grown in a common garden at three plant densities. Wild and domesticated species are compared. The effect of resource availability on those traits during three phenological stages (vegetative, reproductive and maturity) is described. Native species were characterized by traits related to stress-tolerance (high root allocation and low specific leaf area) during the vegetative stage. This suite of traits resulted in low biomass accumulation and low seed-yield. The domesticated O. biennis was characterized by a combination of traits related to stress-tolerance (low specific leaf area) and high productivity (high leaf allocation and leaf area ratio and low root allocation). Domesticated species accumulated more biomass than natives. Total biomass and total non-structural carbohydrates present in roots were positively correlated to seed-yield.Oenothera biennis showed the highest seed-yield, although this species showed yield instability in response to changes in the environmental quality. No changes in seed-yield in response to plant density were recorded for either O. lamarckiana or native species. Oenothera biennis showed an optimum density of 20 plants m−2 and yielded 260 g m−2, a seed-yield similar to that reported in other countries. Low seed-yield of native species is major drawback that must be overcome. Improving seed-yield in these species could be possible by selection oriented to increase total biomass. Since no detrimental effect of density was found in O. lamarckiana and natives, a higher plant density might increase yield production per unit area.  相似文献   

19.
Summary Locally grown seed tubers of nine varieties developing in spring or in autumn in a semi-arid region were examined for length of dormancy and for sprouting response. In spring, high temperatures during the last part of tuber development markedly shortened the dormant periods of tubers in comparison with tubers of the same varieties developing in autumn. The sprouting behaviour of tubers indicated that it is a varietal characteristic influenced by the change in environmental conditions during tuber development and storage. On tubers developing in spring and stored at high temperatures, three sprouting patterns were defined: a) apical dominance, characterized by the evident development of the apical sprout and less than 10% sprouting of the non-apical buds; b) apical influence, the apical sprout well developed and 10–20% sprouting of the non-apical buds; and c) simultaneous sprouting of 3 or 4 sprouts of similar size per tuber. It is suggested that apical dominance is a relative rather than an absolute phenomenon. The extent of dominance depends upon the variety's response to the high temperatures during tuber growth and storage. Contribution from the Agricultural Research Organization, Beit Dagan, Israel, 1979 Series, No 301.  相似文献   

20.
Monomer of acryloyl tri(1,1,2,2-tetrahydroperfluoro-octyl) citrate (FOC) and β-acryloyloxy 1,1,2,2-tetrahydroperfluoro-octyl propionate (FOP) were successfully synthesized and copolymerized with n-butyl acrylate by continuous process emulsion copolymerization. Thermal properties of resulting fluorinated copolymers were characterized by TGA. The water and oil repellency of the polymers used as textile finishing agent on cotton fabrics were investigated, and the surface energies were calculated. The X-ray photoelectron spectrometer (XPS) measurement showed strong surface enrichment of fluorinated segments.  相似文献   

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