东疆沙蜥和密点麻蜥的食性研究

本文对东疆沙蜥和密点麻蜥的食性特征进行了调查研究。结果表明：（１） 这两种蜥蜴的食物组成是小昆虫,主要是鞘翅目、膜翅目和半翅目等对人类有害的昆虫。（２） 食物的充塞度和活动个体数在春季有一个高峰,而在夏季有两个高峰。（３）在食物成分上有季节性变化,在春季主要猎食象鼻虫而夏季主要猎食蚜虫。（４） 它们的有益系数大于其它的两栖类和爬行类动物。     

Diagnostic value of molecular markers for <Emphasis Type="Italic">Lr</Emphasis> genes and characterization of leaf rust resistance of German winter wheat cultivars with regard to the stability of vertical resistance

Breeding for resistance is an efficient strategy to manage wheat leaf rust caused by Puccinia triticina f. sp. tritici. However, a prerequisite for the directed use of Lr genes in breeding and the detection of new races virulent to these Lr genes is a detailed knowledge on Lr genes present in wheat cultivars. Therefore, respective molecular markers for 18 Lr genes were tested for specificity and used to determine Lr genes in 115 wheat cultivars. Results obtained were compared to available pedigree data. Using respective molecular markers, genes Lr1, Lr10, Lr26, Lr34 and Lr37 were detected, but data were not always in accordance with pedigree data. However, leaf rust scoring data of field trials confirmed the reliability of DNA markers. These reliable marker data facilitated the analyses of the development of virulent leaf rust races from 2002 to 2009 based on released cultivars. A sudden change from low infection rates to susceptibility was observed for Lr1, Lr3, Lr10, Lr13, Lr14, Lr16, Lr26 and Lr37 since 2006. Cultivars carrying several leaf rust resistance genes showed no significant shift to susceptibility except one cultivar which revealed an increasing infection rate at a low level. In summary, it turned out that pedigree data are often not reliable and a detection of Lr genes by diagnostic markers is fundamental to combine Lr genes in cultivars for a durable resistance against leaf rust, and to conduct reliable surveys based on released cultivars, instead of ‘Thatcher’ NILs.     

Trace metals and chlorinated hydrocarbons in sewage sludges of Kuwait

Levels of trace metals and chlorinated hydrocarbons were determined in sludge produced at the three main wastewater treatment plants in Kuwait (Ardhiya, Jahra, and Reqqa). Over the 6 mo study period (October 1984 to March 1985) levels at the three plants showed the following ranges (μg g^?1 dry weight); Cd, 0.5 to 5.0; Cu, 90 to 270; Zn, 1100 to 3000; Pb, 80 to 300; Ni, 25 to 60; Hg, 1.8 to 3.6; Ag, 1 to 35; PCBs, 0.1 to 3.6; lindane, 0.4 to 7.4; EDDT (i.e., DDT + DDD + DDE), 0.07 to 0.20; aldrin, below detection to 0.07; endrin, below detection to 0.27; dieldrin, 0.005 to 0.04). Mean levels were generally close or lower than mean concentrations reported in the United Kingdom and the United States. They were also lower than suggested concentration limits for application of sludge on agricultural land, which is one of the most cost-effective and attractive techniques for sludge disposal. For Kuwait to adopt this application, however, the characteristics of the local soil and prevailing environmental conditions, notably the frequent occurrence of severe dust storms, should be considered.     

Optimization of light/dark cycle in an extended photoperiod-based speed breeding protocol for grain legumes

The use of high-performing varieties could contribute to increase food legume production and meet the population demand. However, the long process of conventional breeding is a serious limitation that needs further acceleration of genetic improvement. Speed breeding based on extended photoperiod is one of the techniques that allows rapid generation turnover by accelerating the plant life cycle. The present study focused on optimizing the duration of extended photoperiod for lentil, chickpea and faba bean in a growth chamber with light-emitting diode (LED) light sources. Significant differences in growth rate, biomass production, phenology, physiology, plant injury and yield components were observed depending on light phase durations (22, 18 and 14 h). Twenty-two hours of light resulted in earlier flowering and maturity, but higher stress symptoms than the other two light treatments. However, vegetative development was almost normal with limited stress under 14 h of light, but late flowering and maturity. Interestingly, good plant establishment with limited stress and shorter vegetative cycle was observed under 18 h of light. Therefore, a photoperiod of 18 h of light/6 h of darkness could be advised for a rapid breeding protocol.     

Inhibition of human cAMP-phosphodiesterase as a mechanism of the spasmolytic effect of Matricaria recutita L

Mechanisms underlying the spasmolytic activity of chamomile still remain unclear. Inhibition of cAMP- and cGMP-phosphodiesterases (PDE) is one of the mechanisms operated by spasmolytic drugs. In this study, the effect of chamomile on PDE was investigated. Human platelet cAMP-PDE and recombinant PDE5A1 were assayed in the presence of infusions prepared from sifted flowers and capitula. LC-ESI-MS/MS analysis showed different compositions in infusions made with sifted flowers and capitula. Chamomile inhibited cAMP-PDE activity (IC50 = 17.9-40.5 microg/mL), while cGMP-PDE5 was less affected (-15% at 50 microg/mL). Among the individual compounds tested, only flavonoids showed an inhibitory effect (IC50 = 1.3-14.9 microM), contributing to around 39% of the infusion inhibition; other compounds responsible for cAMP-PDE inhibition still remain unknown. Although experimental evidence supporting the use of chamomile for gastrointestinal minor spasms dates back to the fifties, cAMP-PDE inhibition as a likely mechanism underlying the spasmolytic activity is reported for the first time.     

Identification of bacterial agents causing mortality in postlarvae of giant freshwater prawn (Macrobrachium rosenbergii) in south‐west coastal districts of Bangladesh

Following an incidence of freshwater prawn Macrobrachium rosenbergii postlarvae (PL) mortality in hatcheries in summer 2012, samples from dead PL, rearing water and prawn feed from two south‐west coastal districts of Bangladesh were collected to isolate, identify and characterize the agents causing PL mortality. Antibiogram profile of sixteen randomly selected bacteria, isolated from dead PL, that grew on TCBS, to 20 different antibiotics belonging to 12 major groups revealed that the drug resistance pattern varied from moderate (56% to the drugs: ciprofloxacin, cefotaxime, nitrofurantoin, kanamycin) to complete (to penicillin, ceftazidime and oxacillin) level. To identify the isolates, amplified rDNA restriction analysis (ARDRA) classified them in to four groups, and RAPD (randomly amplified polymorphic DNA) typing yielded nine different types of isolates within these four ARDRA groups. The 16S rDNA gene sequences identified that the groups were genotypically diverse belonging to the bacterial species: Enterobacter cloacae, Klebsiella pneumoniae, Exiguobacterium profundum and Enterococcus casseliflavus, respectively, that all demonstrated their killing potential to PLs in a simulated environment. The study therefore identified four different bacterial pathogens, one of which, Exiguobacterium profundum is reported for the first here in Bangladesh, that demand special consideration for disease management strategy.     

Daily rhythms of cortisol and glucose and the influence of the light/dark cycle on anaesthesia in Nile tilapia (Oreochromis niloticus): Does the timing of anaesthetic administration affect the stress response?

Although daily variations in drug pharmacokinetics have been reported for a variety of teleost species, the influence of this daily variation on the cortisol response following anaesthesia remains poorly understood. To address this, two experiments were performed. The first experiment described the daily patterns of cortisol and glucose secretion in tilapia (Oreochromis niloticus). The second experiment investigated how the timing of anaesthetic administration (specifically at mid‐light [ML] or at mid‐dark [MD]) affects the induction and recovery times and plasma cortisol and glucose levels of juvenile Nile tilapia exposed to benzocaine, clove oil or tricaine methanesulphonate (MS‐222). The results revealed that the effect on the stress response associated with the moment when anaesthesia took place (ML or MD) varied according to the treatment (p < 0.05). Cortisol levels were significantly higher at ML for MS‐222 (ML = 116.23 ± 25.55; MD = 48.25 ± 22.33 ng/dl) (p < 0.05) and clove oil (ML 59.73 ± 14.27; MD 38.26 ± 12.07 ng/dl) (p < 0.05), whereas no significant differences were found between ML and MD cortisol levels for the control treatment (ML = 72.91 ± 18.42; MD = 64.80 ± 10.68 ng/dl) (p > 0.05) or in the benzocaine‐treated group (ML = 38.7 ± 4.90; MD = 38.60 ± 3.69 ng/dl) (p > 0.05). The highest plasma cortisol level in ML was found in the MS‐222‐treated group. All the tested anaesthetics had similar cortisol levels at MD (p > 0.05).     

Milk Yield of Holstein Cows Induced into Lactation Twice Consecutively and Lactation Curve Models Fitted to Artificial Lactations

Nineteen multiparous barren Holstein cows were subjected to an induction of lactation protocol for 21 d administering estradiol cypionate (2 mg kg⁻¹ of body weight (BW) d⁻¹, on day 1 to 14), progesterone (0.10 mg kg⁻¹ of BW, on day 1 to 7), flumethasone (0.03 mg kg⁻¹ of BW, on day 18 to 20) and recombinant bovine somatotropin (rbST; 500 mg per cow, on day 1, 6, 16 and 21). At the end of lactation and with a minimum of a 2-mon dry period, the same cows were again hormonally induced into lactation. Cows in both lactations were not artificially inseminated, they were milked 3 times daily and received rbST throughout lactation. Mean accumulated milk yield at 305 d in milk (DIM) did not differ between the first and second induced lactations ((9 710 ±1 728) vs. (9 309±2 150) kg; mean±SD). Total milk yield ((12 707±3 406) vs. (12 306±4 218) kg; mean±SD) and lactation length ((405±100) vs. (410±91) d; mean±SD) were not different between the first and second induced lactations. In a second study, 15 empirical models including exponential, power law, yield-density, sigmoidal and miscellaneous models were compared for their suitability by modeling 12-mon (n=334), 18-mon (n=164) and 29-mon (n=22) lactation cycles of Holsteins cows induced into lactation and treated with rbST throughout the lactation. Hoerl (Y= ab^1/xx^c), Wood (Y=ax^b exp(cx)) and Dhanoa (Y=ax^(bc)exp(cx)) models were equally suitable to describe 12-mon lactations. An exponential model with five parameters (Y=exp(a+bx+cd²+e/x)) showed the best fit for milk yield for 18-mon lactations. The rational model (Y=a+bx/1+cx+dx²) was found to produce the closest fit for 29-mon lactations. It was concluded that, with the protocol used in the present study, multiparous cows respond favorably to a second cycle of induced lactation, with milk yield similar to that experienced during the first cycle. Thus, dairy producers might be able to lengthen the productive life of infertile high producing cows with a renewal of artificial lactation, which would imply an overall reduction in voluntary culling of cows. Also, various equations used to describe the lactation curves demonstrated the potential for fitting monthly milk records of Holstein cows with prolonged lactations and induced hormonally into lactation.