The purification and characterization of homologous high molecular weight storage proteins from grain of wheat,rye and barley

Summary Homologous high molecular weight storage prolamins were purified from grain of wheat, rye and barley using combinations of gel filtration, ion-exchange chromatography and preparative isoelectric focusing. Sodium dodecylsulphate polyacrylamide gel electrophoresis showed that the components were single bands with apparent mol.wts. of above 100,000. Molecular weights determined by sedimentation equilibrium ultracentrifugation were considerably lower; 54,700, 67,600 and 69,600 for the components from barley, rye and wheat respectively. Amino acid analysis showed the presence of 13.6 to 16.5 mol% glycine, 29.6 to 34.0 mol% glutamate + glutamine, 11.4 to 13.7 mol% proline and a total of 4.0 to 5.7 mol% basic amino acids. Automated N-terminal amino acid sequencing of the component from wheat showed the presence of cysteine residues at positions 5 and 10, and this is discussed in relation to the possible role of these proteins in the visco-elastic gluten network.     

Modification of the basic subunits of pea legumin on storage

Basic subunits of legumin of Pisum sativum undergo a modification on storage of dry seeds which increases their apparent MW on SDS-polyacrylamide gel electrophoresis and decreases their pI values.     

Isolation of legumin-like protein from Phaseolus aureus and Phaseolus vulgaris

An 11S seed globulin has been isolated from Phaseolus aureus and P. vulgaris by zonal isoelectric precipitation and the MWs of the constituent subunits determined. The protein of P. vulgaris occurs in the protein body fraction and its chemical composition, including the N-terminal amino acids and amino acid composition has been determined. The similarity between the 11S globulin of the two Phaseolus spp. and legumin from other leguines is discussed.     

Freezing and Storing Ditylenchus dipsaci in Liquid Nitrogen

After 18 months of storage at -150 C, some larvae of Ditylenchus dipsaci, which had been treated in a 7.5% solution of dimethyl sulphoxide and cooled to -25 C before storage, were still viable on thawing. Some survivors penetrated and developed normally in stems of alfalfa seedlings. Tests showed that active larvae could be frozen directly, thus eliminating the need to use the quiescent stage of this nematode previously thought necessary for successful storage at cryogenic temperatures. The method described is suitable for long-term storage of D. dipsaci and may, with slight modifications, be used to preserve other plant-parasitic nematodes.     

耕地占补面积时空变化对碳储量的影响测度——以湖北省为例

基于InVEST模型定量评估湖北省2000-2020年耕地占补面积时空变化对陆地生态系统碳储量的影响,在县级行政单元尺度探究由耕地占补导致的碳储量变化量在空间上的集聚程度,并运用PLUS模型模拟区域未来四种发展情景下的土地利用格局及碳储量变化趋势。结果表明：（1）2000年至2020年,湖北省耕地面积净变化率为-3.89%,耕地面积略微下降,基本实现耕地占补数量平衡。（2）2000-2005年、2005-2010年、2010-2015年、2015-2020年耕地占用和补偿导致的碳储量变化值占该时段碳储量变化值的比例分别为68.45%、59.45%、57.86%、55.46%,二十年整体占比为61.38%。耕地碳储量的变化对陆地生态系统碳储量的影响巨大。碳固持的地块面积为1.29×10⁵ hm²,碳损失的地块面积为3.88×10⁵ hm²。（3）2000-2020年,湖北省耕地占补导致的碳储量变化值具有明显的空间集聚性,"高高聚集"区主要分布在西部和西南部山区,"低低聚集"区分布在中南部的江汉平原。（4）2020-2030年,湖北省陆地生态系统碳储量在自然发展情景下减少5.50×10⁶ t,在耕地保护情景下减少1.22×10⁶ t,在城镇开发情景下减少8.89×10⁶ t,在生态保护情景下增加2.43×10⁶ t。与其他三种情景相比,生态保护情景是未来发展的最优情景。研究通过定量评估耕地占补平衡背景下湖北省耕地面积时空变化对区域碳储量的影响为未来的国土空间规划以及增汇政策的制定提供决策依据和科学参考,对于实现土地资源的可持续利用和生态环境保护具有重要意义。     

7年穿透雨减少对锐齿槲栎光合固碳及生物量碳储量的影响

气候变化背景下不断加剧的干旱事件对树木的生长及碳积累产生显著影响。然而,树木光合固碳能力及生物量碳储量对相对长期干旱的连续响应机制的研究仍然有限。选择70年生的天然锐齿槲栎(Quercus aliena var.acuteserrata)林,探究长期模拟穿透雨减少对锐齿槲栎光合固碳潜力和生物量碳储量的影响。研究结果表明,连续7年的穿透雨减少处理显著降低了锐齿槲栎的光合固碳能力,其叶片净光合速率(A)、最大羧化速率(V_cmax)、最大电子传递速率(J_max)、最大光化学效率(F_v/F_m)均明显降低,且穿透雨减少处理增强了A与气孔导度(g_s)、J_max、F_v/F_m之间的相关性。在适应长期干旱过程中,锐齿槲栎通过增加比叶面积(SLA)、叶片栅栏组织与海绵组织的比值、气孔密度等叶片形态及结构特性变化,降低冠层叶面积(LAI)指数和蒸腾水分散失及提高水分利用效率(WUE)缓解和适应干旱胁迫的不利影响。但是,长期穿透雨减少仍...     

基于数字土壤制图技术的土壤有机碳储量估算

精准的土壤属性空间分布信息有助于提升土壤有机碳储量估算的精度.本研究以河南省济源市南山林场为研究区,以地形因子为预测因子,利用模糊C均值(FCM)聚类方法对土壤有机碳含量、土壤容重、土壤厚度和土壤砾石含量进行数字土壤预测制图,基于数字制图结果实现土壤有机碳密度预测制图和土壤有机碳储量估算.结果表明:基于数字土壤制图方法...     

中国国家森林公园碳储量及固碳速率的时空动态

森林生态系统在调节气候变化和维持碳平衡中具有重要作用.国家森林公园是森林保护的主要载体,探明其碳储量和固碳速率的变化对于森林生态系统的固碳能力评估和可持续经营管理具有重要意义.本研究采用生态系统过程模型CEVSA2模型,模拟了1982-2017年中国881处国家森林公园的碳密度、碳储量和固碳速率的空间分布特征.结果 表...     

Crystal structure of a secreted insect ferritin reveals a symmetrical arrangement of heavy and light chains

Ferritins are iron storage proteins made of 24 subunits forming a hollow spherical shell. Vertebrate ferritins contain varying ratios of heavy (H) and light (L) chains; however, known ferritin structures include only one type of chain and have octahedral symmetry. Here, we report the 1.9A structure of a secreted insect ferritin from Trichoplusia ni, which reveals equal numbers of H and L chains arranged with tetrahedral symmetry. The H/L-chain interface includes complementary features responsible for ordered assembly of the subunits. The H chain contains a ferroxidase active site resembling that of vertebrate H chains with an endogenous, bound iron atom. The L chain lacks the residues that form a putative iron core nucleation site in vertebrate L chains. Instead, a possible nucleation site is observed at the L chain 3-fold pore. The structure also reveals inter- and intrasubunit disulfide bonds, mostly in the extended N-terminal regions unique to insect ferritins. The symmetrical arrangement of H and L chains and the disulfide crosslinks reflect adaptations of insect ferritin to its role as a secreted protein.     

Practising Conservation Biology in a Virtual Rainforest World

The interdisciplinary science of conservation biology provides undergraduate biology students with the opportunity to connect the biological sciences with disciplines including economics, social science and philosophy to address challenging conservation issues. Because of its complexity, students do not often have the opportunity to practise conservation biology. To increase exposure to this science, this paper describes a virtual rainforest island on which students collect data related to forest carbon storage, while also confronting ethical issues. Students are asked to independently make decisions, collect data and explore the island before writing a research report with recommendations for the future management of the island’s forests. The ethics of decision-making are addressed in the students’ research reports and are reinforced through guided class discussion. Students will complete this activity with increased ethical awareness, as well as a better understanding of the challenges associated with the practise of conservation biology.