An improved method with a wider applicability to isolate plant mitochondria for mtDNA extraction

Background

Mitochondria perform a principal role in eukaryotic cells. Mutations in mtDNA can cause mitochondrial dysfunction and are frequently associated with various abnormalities during plant development. Extraction of plant mitochondria and mtDNA is the basic requirement for the characterization of mtDNA mutations and other molecular studies. However, currently available methods for mitochondria isolation are either tissue specific or species specific. Extracted mtDNA may contain substantial chloroplast DNA (cpDNA) and nuclear DNA (nDNA) and its end use efficiency can be reduced. Clearly, an effective mitochondria isolation method is warranted with wider applicability and with minimum contamination from cpDNA and nDNA.

Results

Here we reported an improved method for isolating mitochondria from dry wheat seeds and its extension to dead seeds, viable seeds, etiolated leaf tissue and several other plant species: oat, Arabidopsis, flax, and yellow mustard. The isolated mitochondria were successfully used to extract mtDNA with QIAamp DNA mini kit (Qiagen). The extracted mtDNA from the assayed samples of these species was intact in large quantity and showed little contamination from nDNA, cpDNA, RNA, and proteins. The mtDNA extracted from dead wheat seeds was also substantial, but more degraded and less intact when compared to those from viable seeds and other tissues.

Conclusion

The improved method was successfully applied to isolate mitochondria and extract mtDNA from several different tissues and plant species. The major advance in the improvement lies in its wider application with the same mitochondria extraction medium to different tissues and species. The improvement is significant, as it helps to widen the scope of future plant mitochondria research.

     

Characterization of Embryonic Stages through Variations in the Egg＇s Contents in Spodoptera fitura

This paper describes the embryonic development of the common cutworm Spodoptera litura （Fabricius） （Lepidoptera： Noctuidae） which is divided into eight embryonic stages, through variations in the egg＇s contents. Experiments were conducted on the eggs ofS. litura under laboratory conditions. The highest concentration of the protein （min.-max.： 32-! 40 lag/egg） and the lowest of the carbohydrate （min.-max.： 3.0-44.0 lag/egg） were obtained; similarly, the DNA content was smaller （min.-max.： 1.0-38.2 lag/egg） than the RNA （min.-max.： 9.2-360.0 lag/egg） throughout the embryogenesis. Three peaks of ecdysteroid titre were observed which were responsible for appearance of particular events during embryogenesis. The last highest peak of 400_＋33.4 lag/egg was appeared at 84 h after oviposition when larva was ready to hatch. Therefore, it is concluded that eight embryonic stages in S. litura were characterized by fluctuation in the egg＇s contents, which were responsible for gradual-progressive embryonic development. The egg-larval development did not show a normal distribution of embryonic developmental-time.     

不同施氮下双季稻田白天CO2交换与叶面积、生物量的相互影响

研究缓/控释氮肥、氮肥配施硝化抑制剂和微生物菌剂对稻田生态系统白天CO_2净交换、群体叶面积和生物量的影响及其相互关系,有助于进一步了解这几类新型氮肥对稻田碳同化的促进作用及增产效果。为此于2012—2013年在湖北荆州进行大田试验,设置了五种氮肥处理:常规尿素(CK)、树脂包膜控释尿素(CRU)、尿素添加硝化抑制剂氯甲基吡啶(NU)、尿素添加硝化抑制剂二甲基吡唑磷酸盐(DMPP)、尿素配施微生物菌剂(EM)。采用静态箱-气相色谱法连续观测双季稻生态系统白天的CO_2净交换通量,并在各生育期测定水稻群体的叶面积和地上生物量,分析不同氮肥处理下这些指标的变化。结果表明:水稻生长季稻田生态系统白天表现为CO_2的净吸收,净交换通量受气温、降水等气象要素影响较大,在拔节-抽穗阶段出现较高值。相比普通尿素,新型氮肥在不同程度上提高了稻田CO_2净交换,在单个水稻生长季NU提高了13.2%~51.6%的平均CO_2净吸收通量,其次为CRU提高了9.8%~34.1%。在各生育期,新型氮肥对水稻群体叶面积指数和地上生物量表现出更高的促进效果,其中以CRU最为显著,其最大峰值相比CK分别提高了12.4%~18.6%和9.1%~18.8%。通过回归分析发现,水稻群体叶面积指数与CO_2净吸收通量为线性正相关关系,地上生物量与CO_2净吸收通量为抛物线型关系,这在一定程度上说明了水稻群体生长状况与稻田生态系统CO_2同化速率间的关系。包膜控释尿素、添加硝化抑制剂、添加微生物菌剂有助于提高水稻群体叶面积和生物量,促进稻田生态系统CO_2同化,其中树脂包膜控释尿素效果最佳。     

Response to partial replacement of yellow corn with potato processing waste as non-traditional source of energy on the productive performance of Ossimi lambs

Twenty-one male growing lambs aged 6 months with an average weight 27.6 ± 0.24 kg were used to determine the effects of partial replacing yellow corn with potato processing waste (PPW) on performance of Ossimi lambs. Animals divided into three equal groups and assigned for control and two experimental diets containing PPW which was replaced from yellow corn at 0% PPW (R₁), 25% PPW (R₂), and 50% PPW (R₃). The results showed that tested rations were almost isocaloric and isonitrogenous. Dietary treatments had no significant effect on feed intake, while water intake insignificantly decreased. Digestibility coefficients of dry matter, organic matter, and crude protein significantly (P < 0.05) improved. However, dietary treatment had no significant effect on crude fiber and nitrogen-free extract digestibilities. Values of total digestible nutrient and digestible crude protein significantly (P < 0.05) increased. Nitrogen retention was positive for all groups. Dietary treatments had no significant effect on ruminal pH but insignificantly decreased ammonia nitrogen (NH₃–N) concentrations. However, total volatile fatty acid concentration was increased. Dietary treatments increased molar proportion of volatile fatty acids. Final weight, body weight gain, and average daily gain were significantly (P < 0.05) decreased, while feed conversion ratio insignificantly decreased. Inclusion of PPW decreased total daily feeding costs of experimental rations. PPW could be used as a source of energy in lamb rations instead of corn grain. Also, PPW can be successfully fed to lamb without any adverse effect on their performance, and it can be an economical substitute for grain.     

Characteristics of prolactin-releasing response to salsolinol in vivo in cattle

The aims of the present study were to clarify the effect of salsolinol (SAL), a dopamine (DA)-derived endogenous compound, on the secretion of prolactin (PRL) in cattle. The experiments were performed from April to June using calves and cows. A single intravenous (i.v.) injection of SAL (5 mg/kg body weight [BW]) or sulpiride (a DA receptor antagonist, 0.1 mg/kg BW) significantly stimulated the release of PRL in male and female calves (P < 0.05), though the response to SAL was smaller than that to sulpiride. The secretory pattern of PRL in response to SAL or sulpiride in female calves resembled that in male calves. A single i.v. injection of SAL or sulpiride significantly stimulated the release of PRL in cows (P < 0.05). There was no significant difference in the PRL-releasing response between the SAL- and sulpiride-injected groups in cows. A single intracerebroventricular injection of SAL (10 mg/head) also significantly stimulated the release of PRL in castrated calves (P < 0.05). These results show that SAL is involved in the regulatory process for the secretion of PRL, not only in male and female calves, but also in cows. The results also suggest that the potency of the PRL-releasing response to SAL differs with the physiological status of cattle.     

Effect of intercropping, Bradyrhizobium inoculation and N, P fertilizers on yields, physical and chemical quality of cowpea seeds

The present study was aimed to determine the effects of inoculation with Bradyrhizobium strain, intercropping, nitrogen and phosphorus fertilization and their interaction on the yield, physical and chemical properties of cowpea seeds. The results showed that the seed yield of cowpea was significantly (P≤0.05) increased by Bradyrhizobium inoculation, nitrogen and phosphorus fertilizers, but not by intercropping. All treatments of intercropping, P, Bradyrhizobium plus N and Bradyrhizobium plus P treatments significantly (P≤0.05) increased the hydration coefficient and cookability of cowpea seeds compared to untreated plants in both seasons. For chemical composition, all treatments significantly (P≤0.05) increased the dry matter, ash, protein and fiber content of the seeds compared to the untreated plants for the two systems and in both seasons, whereas it significantly (P≤0.05) decreased carbohydrate content of the seeds. Fat content of the seeds was not increased by Bradyrhizobium inoculation and intercropping, but it was significantly increased by nitrogen and phosphorus fertilization. Intercropping, Bradyrhizobium inoculation and nitrogen and phosphorus fertilization significantly (P≤0.05) increased tannin content and in vitro protein digestibility of the seeds compared to untreated plants for both systems and in the two seasons.     

Biochemical and histochemical studies on the digestive gland of Eobania vermiculata snails treated with carbamate pesticides

In this study the land snail (Eobania vermiculata), one of the most abundant gastropod of Egyptian farms, was investigated to determine the lethal toxic action of methomyl and methiocarb and to identify the biochemical and histochemical changes as a function of sublethal dose or concentration on the digestive gland of this snail under laboratory conditions, using topical application and baiting techniques. The results showed that methomyl exhibited greater efficacy than did methiocarb against the snails in both techniques. However, higher mortality rates were obtained in the topical application technique than in the poison bait experiments. Biochemical and histochemical examinations revealed that treatment of the snails with methomyl and methiocarb either by topical application or toxic baits caused significant decrease in carbohydrate, lipid and protein contents. This decrease was also more obvious after topical application than after baiting technique, and methomyl was found to be more toxic than methiocarb.     

ZnO-mediated photocatalytic degradation of Benzopurpurine BP4B in aqueous solution

The photocatalytic degradation of a commercial azo dye Benzopurpurine 4B (BP4B) in aqueous solution was investigated under UV-A light at different operating conditions, including irradiation time, pH solution, initial dye concentration, amount of catalyst, light intensity as well as band gap of other semiconductor groups by UV-spectrophotometric monitoring. The highest decomposition efficiency was obtained at pH 8 as a result of 97.24 % degradation of BP4B for 80 min of irradiation time. Photodecomposition reaction of BP4B dye was correlated with pseudo-first-order kinetic model. The degradation data of BP4B dye were satisfactory described by Langmuir-Hinshelwood (L-H) mechanism.     

Multiple response optimization of rotor yarn for strength,unevenness, hairiness and imperfections

In this study, a multiple response optimization model based on response surface methodology was developed to determine the best rotor speed and yarn twist level for optimum rotor yarn strength and unevenness, and minimum yarn hairiness and imperfections. Cotton yarn of 30 tex, was produced on rotor spinning machine with different twist levels (i.e. 500, 550, 600 and 700 tpm) at different rotor speeds (i.e. 70000, 80000, 90000 and 100000 rpm). Yarn quality characteristics were determined for all the experiments. Based on the results, multiple response optimization model was developed using response surface regression on MINITAB® 16 statistical tool. Optimization results indicate that with the quality of raw material selected for this study, top 50 % quality level, according to USTER® yarn quality benchmarks, can be achieved with 100 % desirability satisfaction for all the selected yarn quality parameters at rotor speed of 77,800 rpm and yarn twist of 700 twists per meter.