Genetic changes from introgression of highland Mexican germ plasm into a Corn Belt Dent population of maize

Summary A backcross population (NZS1) of maize (Zea mays L.) was produced by crossing a highland Mexican population with the elite Corn Belt Dent synthetic AS3, and then by backcrossing to AS3. S₁ lines, S₂ lines, and S₂ testcrosses with an elite tester were used to compare the means, correlations, genetic variances, and predicted gains from selection of NZS1 and AS3 for grain yield, grain moisture at harvest, root and stalk lodging in a cool, temperate environment in New Zealand. The S₁ and S₂ lines from NZS1 had lower mean grain yields, higher levels of root lodging and higher mean grain moistures than the S₁ and S₂ lines from AS3. Mean grain yields of testcrosses of NZS1 and AS3 were similar, but NZS1 testcrosses had higher levels of root lodging. Genotypic variances estimated from S₁ and S₂ lines were larger for grain yield and root lodging for NZS1, smaller for grain moisture, and similar for stalk lodging. Predicted gains from selection for grain yield using intrapopulation methods based on the additive-genetic variance were larger for NZS1, but predicted gains for testcross selection were similar for the two populations. Lines with high combining ability for grain yield and acceptable grain moisture in combination with the tester occurred in NZS1. Because of the higher additive-genetic variance and the occurrence of lines with high combining ability for grain yield, we concluded that populations including highland Mexican germ plasm should be valuable for recurrent selection programs in New Zealand and in other cool, temperate regions.     

高海拔地区肺结核影像表现65例回顾分析

目的：探讨总结高海拔地区肺结核的影像特点,更好的指导临床早期诊断。方法：回顾分析65例西藏高原肺结核的影像特点,总结分析其征象及价值。结果：原发型肺结核3例（5％）,影像表现边缘清楚、密度均匀的致密影,伴有淋巴结增大;侵润型结核31例（48％）,影像表现成分混杂的致密影,可见钙化及卫星灶;血行播散型结核27例（42％）,影像表现两肺弥漫分布的结节影;纤维空洞肺结核4例（5％）,影像表现空洞、纤维化、支气管播散三大特征。结论：高原地区肺结核以侵润型和血行播散型为主,有特定的影像特点,可以用来进行诊断。     

Genetic analysis of adaptation differences between highland and lowland tropical maize using molecular markers

Molecular-marker loci were used to investigate the adaptation differences between highland and lowland tropical maize. An F₂ population from the cross of two inbred lines independently derived from highland and lowland maize germplasm was developed, and extracted F_3:4 lines were phenotype in replicated field trials at four thermally diverse tropical testing sites, ranging from lowland to extreme highland (mean growing season temperature range 13.2–24.6°C). Traits closely related with adaptation, such as biomass and grain yield, yield components, days from sowing to male and female flowering, total leaf number, plant height and number of primary tassel branches (TBN), were analyzed. A large line × environment interaction was observed for most traits. The genetic basis of this interaction was reflected by significant, but systematic, changes from lowland to highland sites in the correlation between the trait value and genomic composition (designated by the proportion of marker alleles with the same origin). Joint analysis of quantitative trait loci (QTLs) over sites detected 5–8 QTLs for each trait (except disease scores, with data only from one site). With the exception of one QTL for TBN, none of these accounted for more than 15% of the total phenotypic variation. In total, detected QTLs accounted for 24–61% of the variation at each site on average. For yield, yield components and disease scores, alleles generally favored the site of origin. Highland-derived alleles had little effect at lowland sites, while lowland-derived alleles showed relatively broader adaptation. Gradual changes in the estimated QTL effects with increasing mean site temperature were observed, and paralleled the observed patterns of adaptation in highland and lowland germplasm. Several clusters of QTLs for different traits reflected the relative importance in the adaptation differences between the two germplasm types, and pleiotropy is suggested as the main cause for the clustering. Breeding for broad thermal adaptation should be possible by pooling genes showing adaptation to specific thermal regimes, though perhaps at the expense of reduced progress for adaptation to a specific site. Molecular marker-assisted selection would be an ideal tool for this task, since it could greatly reduce the linkage drag caused by the unintentional transfer of undesirable traits. Received: 10 October 1998 / Accepted: 9 April 1999     

Genetic diversity in traditional Ethiopian highland maize accessions assessed by AFLP markers and morphological traits

In the highland regions of Ethiopia the heterogeneity of the land, the climate, and soil favors the presence of a large number of landraces. We analyzed a representative sample of 62 traditional Ethiopian highland maize accessions, using amplified fragment length polymorphism (AFLP^®) markers and morphological traits with the aim to group the accessions based on the their genetic profiles and morphological traits, to study agroecological variation and to assess the level of correlation between phenotypic and genetic distances. Eight EcoRI/MseI primer combinations and 15 morphological traits were used. The accessions varied significantly for all of the measured morphological traits. Of a total of 650 AFLP markers that were scored, 89.5% were polymorphic. Pair-wise genetic distance estimates based on AFLP data revealed dissimilarity coefficients ranging from 0.32 to 0.69 (mean of 0.57). Cluster analysis of the AFLP data grouped most accessions collected from the Northern highlands into one major cluster. It, however, failed to separate the Western and Southern accessions into different clusters. Regardless of the large variation in environmental conditions between agroecologies, only 9% of the total genetic variation was found between agroecologies, whereas 91% was found within agroecologies in Ethiopia. This finding may be explained by long distance seed exchange, continuous seed introduction and gene flow between agroecologies. The relationship between morphological and AFLP-based distances was significant and positive. Based on this study, three groups of highland accessions, with distinctive genetic profiles and morphological traits were identified. This information will be useful for further collections and conservation of the unique diversity included in the highland maize landraces of Ethiopia.     

Selectively screen the antibacterial peptide from the hydrolysates of highland barley

Highland barley is one of the most important industrial crops in Tibetan plateau. Previous research indicated that highland barley has many medical functions. In this work, the antibacterial abilities of highland barley were investigated. The protein solutions hydrolyzed by trypsin for 4 h exhibited the highest antibacterial activity. An antibacterial peptide, barleycin, was screened and purified by magnetic liposome extraction combining with the protein profiles of reversed‐phase high‐performance liquid chromatography (RP‐HPLC). Structure, characterization, and safety evaluation of barleycin were further investigated. Amino acids sequence was determined as Lys‐Ile‐Ile‐Ile‐Pro‐Pro‐Leu‐Phe‐His by N‐sequencing. Circular dichroism spectra indicated the a‐helix conformation of barleycin. The activity spectrum included Bacillus subtilis, Staphylcoccus aureus, Listeria innocua and Escherichia coli and the MICs were from 4 to 16 μg/mL. Safety evaluations with cytotoxicity and hemolytic suggested this antibacterial peptide could be considered as safe at MICs. Finally, mode of action of barleycin on sensitive cells was primarily studied. The results suggested the damage of cell membrane.     

New species of Selaginella (Selaginellaceae) from the Guayana Highland of Venezuela

Three new species of Selaginella are described from the Guayana Highland of Venezuela: S. cardiophylla, S. hemicardia and S. pruskiana. They are illustrated and the relationships of each are discussed. Another species, provisionally determined as S. terezoana, is reported for the first time from Guyana.     

Discovery of 2,3′-diindolylmethanes as a novel class of PCSK9 modulators

Proprotein convertase subtilisin/kexin type 9 (PCSK9) promotes the degradation of low density lipoprotein receptor (LDLR). Anti-PCSK9 agents have been approved for the treatment of hypercholesterolemia. We recently discovered a series of small-molecule PCSK9 modulators that contains a relatively small pharmacophore of 2,3′-diindolylmethane with molecular weights around only 250. These molecules can significantly lower the amount of PCSK9 protein in a cell-based phenotypic assay. Our SAR studies yielded compound 16 with a IC₅₀-value of 200 nM. No obvious cytotoxicity was observed at concentrations below 50 µM.     

Conservation with a Gun: Understanding Landowner Attitudes to Deer Hunting in the Scottish Highlands

Conservation conflicts are often difficult to resolve due to a combination of poorly defined property rights, inadequate funding, high transaction costs, and contrasting value systems among stakeholders. This paper explores these barriers to collaboration in the context of the emerging deer crisis in the Scottish Highlands, where deer numbers are now higher than at any time in recorded history. In particular we explore the potential role of recreational hunting in the government’s strategy to contain rising deer numbers from the landowners’ perspective. Using both qualitative and quantitative analysis we find that hunting traditions and personal preferences, reinforced by antipathy to conservationists and their perceptions of land stewardship, are the major barriers to shooting more deer for conservation objectives. We conclude that an expansion of commercial hunting opportunities is the best practical approach to resolving the current conflict over deer, but conservationists and landowners must work together to create a more positive context for hunter-conservation initiatives and activities.