Zebrafish β-adrenergic receptor mRNA expression and control of pigmentation

Beta adrenergic receptors (β-ARs) are members of the G-protein-coupled receptor superfamily and mediate various physiological processes in many species. The expression patterns and functions of β-ARs in zebrafish are, however, largely unknown. We have identified zebrafish β-AR orthologs, which we have designated as adrb1, adrb2a, adrb2b, adrb3a and adrb3b. adrb1 was found to be expressed in the heart and brain. Expression of adrb2a predominated in the brain and skin, whereas adrb2b was found to be highly expressed in muscle, pancreas and liver. Both adrb3a and adrb3b were exclusively expressed in blood. Knock-down of these β-ARs by morpholino oligonucleotides revealed a functional importance of adrb2a in pigmentation. Expression of atp5a1 and atp5b, genes that encode subunits of F1F0-ATPase, which is known to be involved in pigmentation, was significantly increased by knock-down of adrb2a. Our data suggest that adrb2a may regulate pigmentation, partly by modulating F1F0-ATPase.     

Fertile heteroallelic combinations of mutant alleles of the otu locus of Drosophila melanogaster

Summary This paper describes the ovarian pathologies observed when 108 different heteroallelic combinations were made involving 17 independent mutations at the ovarian tumor (otu) locus. Most of the mutant phenotypes can be explained as graded responses by individual germ cells to different levels of functionally active otu gene product (OGP) synthesized by the mutant cells themselves. The lowest and highest levels of OGP appear to be produced by otu ¹⁰ and otu ¹⁴, respectively. In most heteroallelic ovaries the alleles have additive effects, and hybrid germ cells reach a developmental stage more advanced than the weaker homozygote but less advanced than the stronger homozygote. However, examples of both positive and negative complementation also have been found, and these suggest that the products encoded by different mutant alleles can combine to form dimers or multimers which may be superior or inferior to the homodimers. In flies homozygous for otu ¹¹ most ovarioles contain tumors, but some germ cells are able to develop further than those in otu ¹⁴ homozygotes. This suggests that, while otu ¹¹ produces intermediate levels of OGP, it also produces a second product (which otu ¹⁴ cannot make) that is utilized at the period in oogenesis when development in cells homozygous for otu ¹⁴ is blocked. When otu ¹¹ is combined with any one of eight specific alleles, it allows oocyte/nurse cell syncytia to differentiate that can complete development and undergo embryogenesis, if fertilized. The endopolyploid nurse cells of these hybrids have giant polytene chromosomes, and the presence of GPCs in functionally active, germ-line derived cells provides an interesting new system for experimental study. Analysis of the characteristic ovarian pathologies produced by flies of different genotypes leads to the conclusion that the products of the otu ⁺ gene are utilized during at least six different periods in Drosophila oogenesis.     

Pollen content study of the lower atmosphere in León (Spain) by use of a tethered balloon

This study was undertaken in order to understand thebehaviour of airborne pollen grains, namely therelationship between their concentrations andconcomitant meteorological parameters, at differentaltitudes (ground level, 200, 400 and 600 m) of thelower atmosphere and its daily variations over onesite (the experimental farm of the University ofLeón). The experimental design involved a tetheredballoon (2.25 m³), an ADAS remote meteorologicalstation and an original radio controlled three headedpollen and spore sampler (called GABIS) using theRotorod design. Each head sampled a differentaltitude, while two control samples were taken atground level. Twenty-one takeoffs could be realized inthe 5 weeks period between end of May and end of June1997. Sampling was done early in the morning and sampling time at each altitudewas of 15 minutes. Results show that 45 differenttypes of pollen grains could be collected at this timeof the year and that significant variations could beobserved in the behaviour of the pollen cloud on a dayto day basis, probably because of differentmeteorological situations. Contrary to what isgenerally believed, pollen was in most cases moreabundant at higher altitude – on average by 30% ascompared to ground level – making evident anaerobiological layer of transport at about 500 m aboveground. This was especially the case for trees (Quercus and Castanea). The atmosphere MixingRatio was the most explicative factor at 200 m, whiletemperature dominated significance analysis at both400 and 600 m.     

Damage and Reproductive Potentials of Pratylenchus brachyurus and P. penetrans on soybean

Damage and reproductive potentials of Pratylenchus brachyurus and P. penetrans on soybean, Glycine max, cvs. Essex, Forrest, and Lee 68, were determined in microplot tests. Cultivar Essex was generally tolerant to P. brachyurus. Yield of Forrest was suppressed linearly with increasing P_i''s in the sandy soil (r = -0.92) and loamy sand soil (r = -0.99). Low to moderate P_i''s in the sandy clay loam gave an increase in yields as compared to plants without nematodes. Yield was not affected by this nematode in muck. Lee 68 was very sensitive to P. penetrans in microplots. Yield vs. P_i was fitted by a quadratic model (r = 0.82) with yield decreasing sharply as P_i''s were increased. The reproduction of both species decreased with increases in P_i. Lee 68 was a good host for P. penetrans, whereas Essex and Forrest were fair to poor hosts for P. brachyurus.     

Physiological mechanism governing slow and fast development in predatory ladybirds

Aphidophagous and coccidophagous ladybirds, similar to their prey, show marked differences in their pace of life (Dixon, 2000), in particular in their rate of development, with all stages of aphidophagous species developing much faster than those of coccidophagous species. Two hypotheses are proposed to account for the large difference in the pace of life of these two groups. These are that differences in the rate of development are a result of differences in lower temperature thresholds for development or the quality of their respective prey as food (Dixon et al., 2011). Analysis of published results on the rates of development of the eggs of ladybirds indicates that the inverse relationships between the number of day‐degrees required for development (K) and the lower temperature threshold for development (td_min) of these two groups are significantly different. In particular, the respective td_min overlap and K of the aphidophagous and coccidophagous species with a similar td_min are, on average, 38 and 117 day‐degrees (D^o). The relationship between the rate of development (R) and temperature (T) for aphids reared on poor‐ or high‐quality foods indicates that, although the value of td_min of a species depends on food quality, K does not, showing that it is unlikely that K is governed by food quality. Thus, there is little support for differences in either the td_min or food quality governing the difference in the pace of life of these two groups of ladybirds. The results indicate that the physiological mechanism that may govern the difference in the pace of life between these two groups is the number of day‐degrees (K) needed to complete their development. The possible evolutionary reason for this is discussed.     

放牧草地健康管理的生理指标

依据草地对席子和牧的生理响应,用牧草生理低限（PLL）,生理上限（PUL）和再生长期（R期）长度/放牧期（G期）长度的比值（R/G）等指标。构建了放牧草地健康评价的生理阈限双因子法,并以光合作用及其相关参数分析了多年生黑麦草轮牧草地的健康指标。维持草地适宜的双因子生理阈限的R/G比值,旨在放牧后草地功能与健康的完全恢复,是放牧草地可持续经营的目标。     

Acid-induced changes in the in vivo wall-yielding properties of hypocotyl sections of Vigna unguiculata

Elongation growth of hypocotyl sections of Vigna unguiculata under xylem perfusion was significantly enhanced when acid was applied by acid-aerosol to an abraded hypocotyl surface in the air. The in vivo wall extensibility (φ) and the effective turgor (Pⁱ– Y), both of which were determined by the pressure-jump method, increased during acid-induced growth as observed in IAA-induced growth. The intracellular pressure (Pⁱ), however, decreased significantly at the beginning of acid-induced growth whereas Pⁱ scarcely changed in IAA-induced growth. This result indicates that protons increase the effective turgor by decreasing the yield threshold as IAA does. There seems to be no essential difference between proton and auxin in the effects on the in vivo mechanical properties of the surface cell wall.     

Studies on evolutionary and selective properties of hypercycles using a Monte Carlo method

Summary The most relevant properties of hypercycles were previously studied mainly from a theoretical point of view. We have developed a Monte Carlo method simulating hypercyclic organization to obtain information about the dynamics of this prebiotic organization. Nucleation, growth, and selective properties have been tested and the results obtained are in good agreement with those of the theoretical predictions. The influence of hypercyclic organization of the error threshold has also been studied. As a consequence of the emergence of a hypercycle, the value of this threshold decreases. The amount of this decrease depends on the population size. Moreover, for some interval of quality factor values, either the hypercycle organization or an error catastrophe can be produced, depending on the initial conditions. The influence of these phenomena on both the dynamic behavior and evolutionary advantages of the hypercycle, as well as their decisive roles on genome size, are discussed.Presented at the FEBS Symposium on Genome Organization and Evolution, held in Crete, Greece, September 1–5, 1986     

大鼠侧脑室注射精氨酸加压素对针刺镇痛的影响

以钾离子透入法引起大鼠甩尾反应为指标,测定动物的痛阈。由侧脑室注射精氮酸加压素(AVP)后,大鼠痛阈升高33.6％～68.5％,针刺镇痛效应明显加强,痛阈提高202.4％～302.7％。脑室注射抗精氨酸加压素血清,动物痛阈虽无明显变化,但针刺镇痛效应明显削弱,痛阈仅增加41.6％～71.0％。注射抗β-内啡肽血清和抗强啡肽A血清并不阻断AVP增强针刺镇痛效应。本工作的结果提示,脑内AVP参与针刺镇痛,这种作用与脑内内源性β-内啡肽和强啡肽的关系不甚密切。     

孤峰组最底部的牙形刺动物群

在孤峰组底部发现了包括Ｍｅｓｏｇｏｎｄｏｌｅｌｌａ ｎａｎｋｉｎｇｅｎｓｉｓ在内的牙形刺动物群。Ｇｏｎｄｏｌｅｌｌａ ｓｅｒｒａｔａ Ｃｌａｒｋ ｅｔ Ｅｔｈｉｎｇｔｏｎ,１９６２是Ｍｅｓｏｇｏｎｄｏｌｅｌｌａ ｎａｎｋｉｎｇｅｎｓｉｓ（Ｊｉｎ,１９６０）的同义名,Ｍｅｓｏｇｏｎｄｏｌｅｌｌａ ｎａｎｋｉｎｇｅｎｓｉｓ已被北美学者推荐为瓜达洛坪统底界的标志化石。因Ｍｅｓｏｇｏｎｄｏｌｅｌｌａ ｎａ