排序方式: 共有38条查询结果,搜索用时 15 毫秒
1.
Shirin Moradi Mostafa Arab Kourosh Vahdati 《The Journal of Horticultural Science and Biotechnology》2017,92(1):88-97
Most temperate terrestrial orchids are endangered species. Attempts to produce plantlets from plants of the genus Epipactis by asexual methods have totally failed. This study was conducted using somatic embryogenesis as a rapid vegetative propagation technique for conservation of E. veratrifolia. For these purposes, effects of different types of plant growth regulators (PGRs), different types of explants, light and dark conditions, and the effect of gibberellic acid (GA3) and Paclobutrazol (PBZ) were investigated on somatic embryogenesis induction. Abscisic acid (ABA) pre-treatment effectiveness on inducting somatic embryogenesis and increasing the number of embryos per explant were investigated. Subsequently, 16 media were tested to find the best medium for plant regeneration and shoot and root proliferation. BA (3 mg L?1) resulted in a better response than the other PGRs by supporting the development of 17 embryos per protocorm. PBZ, which resulted in 11 embryos per explant, was better than GA3. FAST medium supplemented with organic substances was recognized as the best medium for plant regeneration and shoot and root proliferation. ABA pre-treatment had positive effect on somatic embryogenesis initiation. This study, for the first time, succeeded in finding a rapid and suitable protocol for propagation and genetic resource conservation of E. veratrifolia. 相似文献
2.
Abstract – Topeka shiners ( Notropis topeka ), an endangered minnow species, typically spawn on or around breeding Lepomis sunfish (Centrarchidae) nests. Why spawning Topeka shiners are attracted to these nests is unclear, but having the nesting sunfish provide shiner eggs with improved aeration, a lessening of siltation, and protection from egg predators are possibilities. We tested the substrate utilisation of Topeka shiners in outdoor tanks in the absence of sunfish to determine the shiner's fundamental choice. Shiners were provided with substrate patches of cleaned sand, small gravel, large gravel, and small cobble, and the bare floor of the tank. The substrate above which a male shiner established his territory was used as evidence of choice. A statistically significant choice for sand substrates was demonstrated. This fundamental choice might influence which sunfish nests Topeka shiners use, given that nest substrate characteristics differ both between sunfish species and within species by spawning site location. 相似文献
3.
M. R. Arab 《The Journal of Horticultural Science and Biotechnology》2016,91(3):236-242
Adventitious shoot regeneration from mature cotyledons of GF677 rootstock (Prunus persica × Prunus amygdalus) was achieved in vitro. Thidiazuron (N-phenyl-N-1,2,3-thidiazol-5-yl-urea; TDZ) at 32 µM gave the highest percentage of cotyledons forming adventitious shoots (68.8%) and the highest number of shoots per cotyledon (4.8) on Quoirin and Lepoivre (QL) medium. On QL medium containing 32 µM TDZ, exposure of the proximal segments of cotyledons to darkness at the start of culture increased the percentage of cotyledons forming adventitious shoots (62.5%) when compared with those kept under light conditions (15%). A combination of 0.72 µM gibberellic acid and dark treatment resulted in at least 2.7-fold more elongated shoots than non-treated shoots. The highest rooting percentage (100%) occurred on 0.5× Murashige and Skoog medium supplemented with Gamborg (B5) vitamins and 2 mg l?1 indole-3-butyric acid. Rooted plantlets were acclimatised under greenhouse conditions with a 70% survival rate. 相似文献
4.
Predictors of pregnancy and postpartum haemoglobin concentrations in low-income women 总被引:1,自引:0,他引:1
OBJECTIVE: Pregnancy and postpartum iron status is of great public health importance, yet few studies have examined predictors of haemoglobin (Hb) concentration during this time. We identified predictors of Hb from 24 weeks' gestation until delivery and from 4 to 25 weeks postpartum. DESIGN: Blood was drawn as many as four times during care: at the initial visit, at 24-29 weeks' gestation, at delivery and postpartum. A longitudinal, multivariable linear regression model was used to predict Hb concentration. SETTING: A public health clinic in Raleigh, North Carolina.Subjects: n=520 women who participated in the Iron Supplementation Study. RESULTS: Hb concentration at the previous blood draw, short stature, non-Hispanic white ethnicity/race, >12 years of education and smoking were positive predictors of pregnancy and postpartum Hb concentrations. Iron supplement use was a positive predictor, while inadequate weight gain and severe nausea/vomiting were negative predictors of gestational Hb. A high infant birth weight and postpartum haemorrhage were negative predictors of postpartum Hb. Pre-pregnancy body mass index had a slight positive relationship with gestational Hb, but had a strong negative relationship with postpartum Hb. The longitudinal model also confirmed the typical pattern of gestational Hb concentration. As the number of weeks between the initial visit and the 24- to 29-week visit increased, Hb at 24-29 weeks' gestation decreased. As gestational age increased from 24 weeks until delivery, Hb concentration increased as well. CONCLUSIONS: The predictors identified here could be used in clinical settings to target high-risk women for intervention. 相似文献
5.
Maryam Ahmadi Narges Damavandi Mohammad Reza Akbari Fatemeh Davami 《Iranian Biomedical Journal》2016,20(2):68-76
Mammalian expression systems, due to their capacity in post-translational modification, are preferred systems for biopharmaceutical protein production. Several recombinant protein systems have been introduced to the market, most of which are under clinical development. In spite of significant improvements such as cell line engineering, introducing novel expression methods, gene silencing and process development, expression level is unpredictable and unstable because of the random location of integration in the genome. Site-specific recombination techniques are capable of producing stable and high producer clonal cells; therefore, they are gaining more importance in the biopharmaceutical production. Site-specific recombination methods increase the recombinant protein production by specifically inserting a vector at a locus with specific expression trait. The present review focused on the latest developments in site-specific recombination techniques, their specific features and comparisons. 相似文献
6.
Shahbazfar AA Mardjanmehr SH Arab HA Rassouli A Abdollahi M 《Tropical animal health and production》2011,43(4):843-849
Artemisinin has been used for centuries to treat malaria, intestinal tract helminthosis, diarrhea, and used as an antipyretic
and sedative agent, but the usage in veterinary medicine is a new field. Recently, it has been used successfully to control
experimental poultry coccidiosis. The present study aimed to determine the effects of different doses of artemisinin in broiler
chickens with chronic usage. Sixty birds divided into one control and four treatment groups that fed rations mixed with artemisinin
at doses of 17, 34, 68, and 136 ppm for 36 days. During the experiment, birds showed no clinical signs except anemia. In microscopic
examinations, heart, lung, and spleen had no lesion, but liver, kidney, and brain showed various lesions. Degenerative lesions
like intracytoplasmic eosinophilic inclusions were seen in both kidney and liver but fatty change was seen only in liver.
There was no relationship between severity of the liver lesions and drug dosage. Central chromatolysis, scattered neuronal
necrosis, and mild spongy changes were observed in five regions of the brain that were chosen for sectioning (motor cortex,
cerebellar nuclei, midbrain nuclei, and hindbrain nuclei at two separate levels). Severity of lesions in brain was dose-dependent,
and cerebral cortex was the most vulnerable area. Haematologic tests showed lower values for hematocrit and red blood cell
count dose-dependently. In conclusion, artemisinin is a promising drug for prevention and control of coccidiosis in broiler
chickens and its side effects are not too much serious especially at therapeutic doses. 相似文献
7.
Moslemizade N Rafiei A Yazdani F Hosseini-khah Z Yusefnezhad K 《Pakistan journal of biological sciences: PJBS》2011,14(2):106-111
Preeclampsia is a disease regarding with altered vascular reactivity leading to hypertension of the mother and metabolic alterations in the fetus. This study aimed to assess nitric oxide and bleeding time following administration of magnesium sulfate to preeclamtic patients compared to normotensive pregnant women. A total of 112 subjects (56 preeclamtic patients and 56 normotensive pregnant controls) were enrolled in this case-control study. Cases and controls were matched for age, BMI, gestational age, parity and gravidity. Total concentration of nitrite and nitrate (NOx) was measured before and during magnesium sulfate (MgSO4) treatment using a modified Griess-based method. RESULTS: Systolic and diastolic blood pressures were significantly decreased during MgSO4 treatment in preeclamtic patients (p < 0.0001). NOx levels were significantly increased in preeclamtic women after MgSO4 administration (33.7 +/- 18.5 vs. 50.2 +/- 21.6, p < 0.0001) but it was not seen in normotensive parturients (52.4 +/- 28.9 vs. 57.3 +/- 21.7, p = 0.362). The bleeding time was scarcely increased following magnesium sulfate treatment in preeclamptic patients compared to normotensive pregnant women but it was not significant (p = 0.18). In addition, there was only a significantly reverse correlation between NOx levels and systolic or diastolic blood pressure in preeclamtic parturients after MgSO4 treatment (r = -0384; p = 0.003 and r = -0.29; p = 0.03, respectively). This study demonstrates that administrating MgSO4 to preeclamtic patients induced significant changes in NOx production which had a major role in modulating vasculature changes in preeclamsia. 相似文献
8.
Firouznia K Amirmohseni S Guiti M Amanpour S Baitollahi A Kharadmand AA Mohagheghi MA Oghabian MA 《Pakistan journal of biological sciences: PJBS》2008,11(4):607-612
The aim of this study was to assess the T1, T2 and T2* relaxivity of Ultrasmall Super Paramagnetic Iron Oxide (USPIO) nano-particles in vitro and in vivo in rat models with magnetic resonance imaging at 1.5T. First, relaxation properties of USPIO nano-particles at different doses were measured using related SE and GRE MR imaging protocols. The relation between dose and relaxation were observed which is linear; Higher dose of the nano-particles means higher relaxivity. Based on this relation, an optimum protocol can be proposed for obtaining the best image contrast at each situation. Then detection ability of MRI protocols was studied for USPIO nano-particles with injection of the particles in the rat. The optimum MR protocols were used to observe the signal change of lymph nodes in rat. 相似文献
9.
Arab HA Rahbari S Rassouli A Moslemi MH Khosravirad F 《Tropical animal health and production》2006,38(6):497-503
Artemisinin has received much attention in the treatment of malaria in recent years, and it is now considered as a potential
candidate to reduce coccidial infection in chickens. It is a sesquiterpene compound which has been isolated from Aretemisia annua for the first time. The present study aimed to investigate the occurrence of artemisinin in A. sieberi (AS) and to test the anticoccidial effects of plant extract in broiler chickens. The aerial parts of the plant were collected
during different seasons from Yazd Province, in the centre of Iran. The artemisinin content of the AS was extracted with petrol
ether and analysed by high-performance liquid chromatography using UV detection. Anticoccidial effects of the plant extract
were tested on chicks challenged with various species of Eimeria. The infected chickens were treated with doses of 1 or 2.5 mg/kg per day artemisinin via oral administration of plant extract.
The analytical results showed that the level of artemisinin in AS was 0.2% and 0.14% of dried weight (DW) of plant materials
in summer and autumn, respectively. Treatment of experimentally infected chickens with AS extracts showed that artemisinin
was able to reduce the severity of coccidial infection induced by Eimeria tenella and E. acervulina, but not E. maxima. The anticoccidial effects of artemisinin were shown by significant decrease in output of number of oocysts per gram of faeces
in chickens challenged with different species of Eimeria. This study showed that the levels of artemisinin in AS were comparable with those in other species including A. annua, and that the extract of this plant can reduce coccidial infection in broiler chickens. 相似文献
10.
Abo-Shehada MN Jebreen E Arab B Mukbel R Torgerson PR 《Preventive veterinary medicine》2002,55(3):201-207
From March 1996 to February 1997, slaughtered-sheeps' heads were examined for the metacestode of Taenia multiceps. Out of 451 sheep heads, only 12 (3%) were infested. All cysts but one were in the age group 0.5-2.5 years old, with prevalence of 10% (11 of 108). Eleven of 12 infested heads were found during the spring and autumn seasons. Out of 95 flocks involved in questionnaire survey unrelated to the abattoir survey, all the farmers reported the existence of the clinical signs known for coenurosis and described it in locally known names and diseases. Twenty-five of them had recent cases that were diagnosed by the veterinarian as coenurosis cases. Each flock reported one or two cases at the time of survey. A variety of clinical signs were reported from these cases (n = 42). These included circling (86%), head pressing (52%), blindness (29%) and paresis (40%). Coenurosis is a sheep-health problem and an important cause of sheep culling in Jordan. 相似文献