Discrimination between extreme chronotypes using the full and reduced version of the Morningness-Eveningness Questionnaire

The aim of this study was to carry out a comparison of the ability to discriminate between extreme chronotypes, i.e., morning- and evening-types, among the Morningness-Eveningness Questionnaire (MEQ) and its reduced version (rMEQ). To this end a secondary analysis of cohort studies, using two different approaches, was carried out. The first, subjective, relied on the computing of overlap between extreme chronotypes according to their hourly ideal bedtime, get-up time and midpoint of sleep reported at the MEQ and rMEQ, while the second, objective, on the corresponding actual-actigraphic times. At the subjective approach, 2706 participants filled in the MEQ, while 940 the rMEQ (age range of both groups: 18–30 years). The overlap was significantly lower among those who filled the rMEQ than MEQ when considering ideal midpoint of sleep (13.70% and 46.28%, respectively) and get-up time (47.04% and 62.34%, respectively). At the objective approach, 51 participants filled in the MEQ while 52 the rMEQ (age range: 19–30 years in both groups) at the end of one week of actigraphic recording. No significantly different overlap across those who filled the MEQ or rMEQ was observed with reference to the examined actigraphic times. Results of subjective assessment showed as rMEQ more clearly discriminated between extreme chronotypes than MEQ. The attempt to find an objective confirmation did not provide the same results, probably as a consequence of a masking effect by social rhythms.     

利用SNP标记及配合力划分超甜玉米自交系的杂种优势群

划分超甜玉米自交系的杂种优势群,筛选配合力高的甜玉米自交系,构建新的杂种优势更强的甜玉米群体,为优良甜玉米的选育提供依据.本研究选用23个自育超甜玉米自交系,采用NC Ⅱ设计得到60(3×20)个组合,研究它们的产量配合力效应并结合56K SNP标记将供试材料进行杂种优势群的划分.结果表明23个自交系的平均杂合率为2....     

Unraveling the essential role in conjugation of the Tra protein of Streptomyces lividans plasmid pIJ101

Plasmid pIJ101 from Streptomyces lividans encodes a single gene, tra, that is essential for both plasmid transfer and mobilization of chromosomes during mating. The tra gene product (Tra) is a membrane protein, a portion of which shows similarity to transfer proteins of other streptomycete plasmids as well as additional bacterial chromosome partitioning proteins. This paper reviews past and present work that has focused on elucidating the precise role of the Tra protein of pIJ101 in conjugation in Streptomyces.     

Abscess forming ability of streptococcus milleri group: synergistic effect with Fusobacterium nucleatum.

The abscess forming abilities of "Streptococcus milleri" strains (Streptococcus constellatus, Streptococcus anginiosus, and Streptococcus intermedius) isolated from dentoalveolar abscesses and the synergistic effect of Fusobacterium nucleatum co-inoculated with the isolates were examined on a mouse subcutaneous abscess model. Five days after inoculation, all S. milleri strains formed abscesses, which showed less pathological spread to surrounding connective tissues than those formed by Staphylococcus aureus 209P strain and were similar to those by F. nucleatum ATCC25586. When each S. milleri strain and F. nucleatum were co-inoculated, abscess sizes and each bacterial number recovered from abscesses increased in comparison to those treated by bacterial mono-inoculation of each S. milleri strain or F. nucleatum alone. The strongest synergistic effect was observed in the combination of S. constellatus and F. nucleatum. In a time course experiment with this combination, the recovery of S. constellatus subsequently decreased after the decrement of F. nucleatum, and it appeared that the association with F. nucleatum maintained the bacterial number of S. constellatus in the abscess. The cell-free supernatant of F. nucleatum had a tendency to increase the abscess size caused by S. constellatus in this model. When S. constellatus was cultured with F. nucleatum culture supernatant in vitro, growth enhancement in the early phase was observed. Furthermore, the phagocytic killing of S. constellatus by human polymorphonuclear leukocytes (PMNs) was significantly suppressed and the PMN membranes appeared to be injured by addition of the F. nucleatum culture supernatant. These results suggest that the pathogenicity of S. milleri strains in odontogenic infections may be enhanced by the co-existence of F. nucleatum.     

The activity of abdominal stretch receptors during non-giant swimming in the crayfish<Emphasis Type="Italic"> Cherax destructor</Emphasis> and their role in hydrodynamic efficiency

Recordings were made from the nerve innervating the stretch receptors of the abdominal muscle receptor organs and slow extensor muscles of tethered crayfish, Cherax destructor, during so-called non-giant swimming. The stretch receptors were active during the flexor phase of swimming but the duration and pattern of activity varied from cycle to cycle. Their pattern of firing was modified by the activity of the large accessory neurons which make direct inhibitory synapses upon them. Neither the stretch receptors nor the accessory neurons were active during the extensor phase of the cycle. The timing and extent of tailfan movements during the period of stretch receptor activity were measured from video records before and after the stretch receptor nerves were cut in the second to fifth segments. The promotion of the tailfan during flexion was significantly delayed and the minimum angle to which the uropods were remoted at the end of flexion significantly larger in denervated animals. We propose that afferent information from the stretch receptors coordinates the timing and extent of tailfan movements according to variations in the positioning and movement of the abdominal segments such that the hydrodynamic efficiency of the tailfan is enhanced on a cycle by cycle basis during non-giant swimming.Abbreviations A# abdominal segment number - Acc accessory neuron - LUU large unidentified unit - MRO muscle receptor organ - NGS non-giant swimming - SEMN slow extensor motor neuron - SR stretch receptor neuron     

Fermentative capacity of baker's yeast exposed to hyperbaric stress

Baker's yeast suspensions were incubated at different pressures (from 1 bar to 6 bar) and different gases [air, O(2) and a mixture of 8% (v/v) CO(2), 21% O(2) and N(2)]. Raising the air pressure from 1 bar to 6 bar stimulated cell growth but had no effect on leavening ability or viability of the cells. A 50% reduction of the CO(2) produced in dough occurred with 6 bar O(2) which also stopped growth. The fermentative capacity of the cells was stimulated by the cells exposure to increased CO(2) partial pressure up to 0.48 bar.     

Cassava breeding: opportunities and challenges

Although cassava is a major food crop, its scientific breeding began only recently compared with other crops. Significant progress has been achieved, particularly in Asia where cassava is used mainly for industrial processes and no major biotic constraints affect its productivity. Cassava breeding faces several limitations that need to be addressed. The heterozygous nature of the crop and parental lines used to generate new segregating progenies makes it difficult to identify parents with good breeding values. Breeding so far has been mainly based on a mass phenotypic recurrent selection. There is very little knowledge on the inheritance of traits of agronomic relevance. Several approaches have been taken to overcome the constraints in the current methodologies for the genetic improvement of cassava. Evaluations at early stages of selection allow for estimates of general combining ability effect or breeding values of parental lines. Inbreeding by sequential self-pollination facilitates the identification of useful recessive traits, either already present in the Manihot gene pool or induced by mutagenesis.     

Comparison of competitive ability between native and introduced salmonids: evidence from pairwise contests

Brown trout, Salmo trutta, and rainbow trout, Oncorhynchus mykiss, have been introduced to freshwaters in Hokkaido, Japan. Today, it is recognized that these introduced salmonids have negative impacts on native salmonids such as white-spotted charr, Salvelinus leucomaenis, and masu salmon, O. masou. In particular, interspecific competition may be an important mechanism that could contribute to the exclusion for native salmonids. In this study, experimental pairwise contests were conducted to compare interference competitive ability between native and introduced salmonids. We demonstrated that brown trout were competitively superior to white-spotted charr and masu salmon whereas rainbow trout were superior to white-spotted charr. We suggest that introduced brown trout negatively impact both white-spotted charr and masu salmon, and introduced rainbow trout negatively impact white-spotted charr.     

Genetic characterization and specific detection of beer-spoilage Lactobacillus sp. LA2 and related strains

AIMS: Lactobacillus sp. LA2 (DSM15502) and related strains (LA2 group) possess strong beer-spoilage ability. The 16S rDNA sequence of LA2 strain is virtually indistinguishable from that of L. collinoides, generally considered to be nonbeer-spoilage bacteria. The aim of this study was to identify the genetic marker to distinguish between Lactobacillus sp. LA2 group and L. collinoides and to provide a rapid means of identifying beer-spoilage strains belonging to Lactobacillus sp. LA2 group. METHODS AND RESULTS: The 16-23S rDNA intergenic spacer (ITS) regions of Lactobacillus sp. LA2 and L. collinoides JCM1123T were sequenced to identify a genetic marker to distinguish between the two groups. As a result, 300 and 500 bp ITS regions of Lactobacillus sp. LA2 were found to be almost identical with those of L. collinoides JCM1123T. Sequence comparison analysis between Lactobacillus sp. LA2 and L. collinoides JCM1123T revealed that the two contiguously located nucleotides are absent in both ITS regions of Lactobacillus sp. LA2. Based on the sequence difference, we have designed specific PCR primers with a minor modification to the primer sequence that can differentiate between beer-spoilage Lactobacillus sp. LA2 group and nonbeer-spoilage L. collinoides. CONCLUSIONS: The PCR-based method has been developed to identify Lactobacillus sp. LA2 group, providing a rapid and sensitive means of determining the beer-spoilage ability of detected bacterial strains. SIGNIFICANCE AND IMPACT OF THE STUDY: The substitution of one nucleotide, located at the third position to the 3'-end in the primer sequence, enhanced the specificity of the PCR method while retaining sufficient sensitivity. The nucleotide gap identified in this study appeared to serve as a useful genetic marker that can differentiate 12 beer-spoilage Lactobacillus sp. LA2 group strains from its close relatives that exhibit no beer-spoilage ability.     

土壤干旱对元宝枫渗透调节能力的影响

采用盆栽控水法和P—V技术研究分析了不同土壤干旱(速度、程度)条件对元宝枫渗透调节能力的影响。结果表明,元宝枫具有很强的渗透调节能力．但该能力受土壤干旱的速度和程度影响,在缓慢干旱条件下,元宝枫叶片的ψw、ψ0、π100、RWC^0、ROWC^0均明显降低．其中与渗透调节能力直接相关的(π100可下调0．52MPa,ψ0下调1．51MPa。在快速干旱条件下π100和ψ0分别仅下凋0．20MPa和0．48MPa。△π100值也表明缓慢干旱条件下元宝枫渗透调节能力是快速干旱下的45倍。在缓慢干旱条件下．由轻度到中度干旱时其渗透调节能力显著增强(增加270％);由中度到严重干旱时．增加不明显(增加了24．5％)。从3种有机渗透调节物质含量与△π100值的动态变化可见,可溶性糖含量增加对渗透调节能力的贡献是第一位的．其次是Pro、游离氨基酸。