Micro-scaled high-throughput digestion of plant tissue samples for multi-elemental analysis

Background  

Quantitative multi-elemental analysis by inductively coupled plasma (ICP) spectrometry depends on a complete digestion of solid samples. However, fast and thorough sample digestion is a challenging analytical task which constitutes a bottleneck in modern multi-elemental analysis. Additional obstacles may be that sample quantities are limited and elemental concentrations low. In such cases, digestion in small volumes with minimum dilution and contamination is required in order to obtain high accuracy data.     

Artificial Insemination of Gilts with 1.5 Billion Sperms Stored in Different Periods Associated with Different Pre-ovulatory Intervals

This study evaluated the reproductive performance of gilts inseminated at three intervals before ovulation (0-12, 13-23, 24-30 h) with sperm doses (SD) stored for 0-48 and 96-120 h. A total of 218 PIC Camborough 22 gilts were inseminated once with SD of 1.5 x 10(9) sperms. Pregnant gilts (n = 166) were slaughtered 30.8 +/- 3.7 days after artificial insemination. The number of corpora lutea (CL) and total embryos (TE) was counted. Pregnancy rates (PR) were analysed by chi-square test. TE and embryonic survival (ES), obtained as the ratio between viable embryos and CL, were analysed by GLM procedure (SAS) and mean values were compared by Tukey's test. Pregnancy rate was similar among artificial insemination-ovulation (AIOV) intervals when semen was stored for 0-48 h. However, the lowest PR was observed in the 24-30 h AIOV interval with storage time (ST) of 96-120 h (p < 0.05). There was a significant effect of the interaction between ST and AIOV (p < 0.05) on TE and ES variables. Total embryos and ES did not differ (p > 0.05) among AIOV intervals in ST of 0-48 h. However, gilts inseminated at 24-30 h AIOV interval with ST of 96-120 h showed a reduction of 6.7 embryos (p < 0.05) compared with gilts in the same interval inseminated with semen stored for 0-48 h. ES for the 24-30 h AIOV interval and ST of 96-120 h was lower than that observed in the other groups (p < 0.05).     

Characterization of monoclonal antibodies against avian reovirus S1133 protein sigmaA synthesized in Escherichia coli

Monoclonal antibodies (MAbs) were prepared against avian reovirus S1133 protein sigmaA (esigmaA) synthesized in Escherichia coli. MAbs were characterized and used to develop a diagnostic test. Ten MAbs were selected for competitive binding assay following coupling with horseradish peroxidase. The results indicated that these MAbs delineated two epitopes I and II of esigmaA. An immuno-dot binding assay was used to detect the effect of denaturation on antibody recognition of the epitopes. All MAbs bound to esigmaA in its native form. After denaturation by boiling in SDS and 2-mercaptoethanol, the binding of MAbs recognizing epitope I was fully abolished. However, the reactivity of MAbs recognizing epitope II was not affected. MAbs 31 and 32, recognizing epitopes I and II, respectively, were selected for the cross-reactivity to heterologous reovirus strains. The results suggest that the two epitopes are highly conserved among these virus strains. A MAb capture enzyme-linked immunosorbent assay (ELISA) procedure was developed using MAbs 32 and 31 to detect reovirus protein sigmaA in samples from tendon tissues of infected bird and chicken embryo fibroblast (CEF) cell cultures. Avian reovirus sigmaA antigens in tendon specimens were detected from the inoculated birds as early as 2 days post-inoculation (PI), approximated a peak at 7 days PI, and maintained this until 16 days PI, then decreased gradually. A clear difference in absorbance values between the tendon samples of the avian reovirus- and mock-infected birds is obtained. Positive results were also obtained from avian reovirus-infected CEF and from the tendon tissues of naturally infected broilers. These results indicated that the MAb capture ELISA is a useful methods for the detection of avian reovirus from chickens suspected to have avian reovirus infections.     

大兴安岭林区森林抚育工程系统输出特性和转化特性的研究

为提高大兴安岭林区森林抚育工程作业质量和工程成效,采用系统工程的分析方法,根据大兴安岭林区生态环境、功能和林木的结构特点,对大兴安岭林区最主要的三种抚育类型(透光抚育、生长伐抚育、生态疏伐抚育)的直接输出特性、长效输出特性和转化特性进行了详细分析。在此基础上,利用运行控制和统计学理论,通过调整输出特性偏移量、输出特性标准偏差和输出特性公差要求,提高工程能力,进而优化输出特性,最终实现提高工程作业质量和工程成效的目的。对输出特性和转化特性的分析研究,为大兴安岭林区森林抚育工程技术要求标准的产出提供基础和支撑。     

中国良种推广补贴政策实践及启示

中国加入WTO以来,中国良种补贴政策开始逐步实施。补贴的品种、范围和规模不断扩大,其成效也越来越明显。笔者认为:良种补贴已成为中国农业补贴的重要内容,是一项重要的支农惠民政策。良种补贴符合农业科技发展的实际,有效地推动了科技贡献率的提高,已成为一项提升粮食综合生产能力的重大发展政策。     

The Post‐Cervical Insemination does not Impair the Reproductive Performance of Primiparous Sows

The study evaluated the reproductive performance of primiparous sows submitted to post‐cervical insemination (PCAI) compared with cervical artificial insemination (CAI). Difficulty with catheter introduction, the occurrence of bleeding or semen backflow during insemination, and volume and sperm cell backflow up to 60 min after insemination were also evaluated. Sows were homogenously distributed, according to body weight loss in lactation, lactation length, weaned piglets, weaning‐to‐oestrus interval and total born in previous farrowing, in two treatments: PCAI (n = 165) with 1.5 × 10⁹ sperm cells in 45 ml (2.4 ± 0.04 doses per sow) and CAI (n = 165) with 3 × 10⁹ sperm cells in 90 ml (2.5 ± 0.04 doses per sow). During PCAI, sows were inseminated in the absence of boars. Transabdominal real‐time ultrasonography was performed at oestrus onset, immediately before the first insemination and at 24 h after last insemination. There was no difference (P > 0.05) between treatments in farrowing rate (91.5% × 89.1%) and litter size (12.5 × 11.9 piglets born, respectively for PCAI and CAI sows). Successful passage of the intrauterine catheter in all the inseminations was possible in 86.8% (165/190) of sows initially allocated to PCAI treatment. Difficulty of introducing the catheter in at least one insemination did not affect the reproductive performance of PCAI sows (P > 0.05). Bleeding during insemination did not affect (P > 0.05) the farrowing rate in both treatments, but litter size was reduced in CAI and PCAI sows (P ≤ 0.06). Percentage of spermatozoa present in backflow within 1 h after insemination was greater in CAI than PCAI sows (P < 0.01). More than 85% of primiparous sows can be successfully post‐cervical inseminated with doses containing 1.5 × 10⁹ sperm cells in the absence of the boar during insemination without impairing the reproductive performance.     

Importance of extensional rheological properties on fiber-enriched corn extrudates

Incorporation of insoluble fibers into extruded cereals severely limits their expansion and reduces crispness. The specific objective of this work was to investigate how corn bran and its fractions mixed with cornmeal affect rheology and extrudate expansion. Alkali-treated bran (ATB) and alkaline-soluble bran (ASB) were prepared from unmodified corn bran (UMB). Mixtures of the different corn bran fractions and degermed cornmeal having a 26% (w/w) of total dietary fibers were extruded in a twin screw extruder and expansion of the extrudates was determined. Melt shear rheology of mixtures of cornmeal and different corn bran fractions having a 20% total dietary fiber was determined using a capillary rheometer at 120 °C while the extensional rheology was determined using lubricated squeezing flow. The expansion of extrudates containing ATB was larger than those containing UMB, while extrudates containing ASB showed a greater expansion that was close to that of the control. Addition of UMB to cornmeal increased shear and extensional viscosity significantly as compared to the control. ATB addition increased the shear viscosity of the mixture to a small extent but showed the highest extensional viscosity amongst the samples. Addition of ASB resulted in mixtures having lower shear and extensional viscosities than the control.     

Fiber Types Distribution in the Digastric Muscle of Tufted Capuchin Monkey (Cebus apella)

Fiber types distribution in the diagastric muscle of tufted capuchin monkey was studied by means of NADH-TR, myosin-ATPase, after alkaline and acid preincubations and SDH histochemical reactions. Three different types of fibers were found presenting an equal distribution. The percentage and types of fibers were as follow: 18.2 % SO (Slow Oxydative), 38.4 % FOG (Fast Oxydative Glycolytic) and 43.4 % FG (Fast Glycolytic). FG fibers revealed the largest area. The relatively high concentration of fast twitch (81.2 %) seems to indicate this muscle is involved with the acceleration and fast speed of jaw movements. Aerobic metabolism represented by SO + FOG fibers (56.6 %) suggestes that this muscle possesses an additional role than that related to the lowering of the jaw.