Location along the muscle's length is a determinant of myofibril size

In a previous study of myofibril size in 'Pale' (fast-twitch-glycolytic) fibers of rabbit extraocular muscle (EOM), it was found that individual long Pale fibers demonstrate a substantial increase in the size of myofibril profiles from their proximal to their distal halves (Davidowitz et al., 1996b). That finding raised the question of whether such proximal-to-distal increase of myofibril size in the Pale fibers is determined by: (1) longitudinal position within the individual muscle fibers themselves or (2) location along the length of the muscle as a whole? This question was tested in the present study by comparing the original group of long Pale fibers, which extend the full length of the muscle, with two groups of short Pale fibers, which are respectively confined to the proximal and distal halves of the muscle. It was found that (a) in the proximal half of the muscle, the short fibers and the adjacent portions of the long fibers have the same smaller size of myofibrils, and (b) in the distal half of the muscle, the short fibers and the adjacent portions of the long fibers have the same larger size of myofibrils. This finding indicates that the proximal-to-distal increase of myofibril-profile size in these EOM Pale fibers is determined by location along the length of the muscle as a whole, and is not related to longitudinal position within the individual fibers themselves.     

Environmental drivers of nematode abundance and genus composition at two spatial scales on an estuarine intertidal flat

Hydrobiologia - The dwarf morph of Telmatochromis temporalis uses empty snail shells as shelters and spawning sites. This morph varies in body colour from pale to dark within populations. Pale...     

The social system of the Pale Chanting Goshawk Melierax canorus; monogamy v polyandry and delayed dispersal

The social organization and reproductive strategy of the Pale Chanting Goshawk Melierax canorus were investigated in four southern African study areas. Territories supporting adults additional to the breeding pair were observed in two study areas. Within one of these areas, these additional adults were either non-breeders staying in their natal territory but actively excluded from the nesting area during the breeding season or a male cobreeder participating fully in reproductive activities with the breeding pair. Polyandrous trios were, however, observed in only one vegetation type in this area, Broken Veld. The annual number of offspring fledged per group did not differ significantly between vegetation types nor between polyandrous trios and monogamous pairs within Broken Veld. Pale Chanting Goshawks lay predominantly two-egg clutches. In 2 out of 5 years, breeding groups succeeded in laying, hatching and even fledging a second brood of young after successfully fledging their first brood. Double brooding occurred more frequently in Broken Veld and most frequently in polyandrous trios in this vegetation type. To accommodate their relatively long breeding cycle (>115 days) in this temperate study area with its limiting summer breeding period, double-brooding Pale Chanting Goshawks laid the first clutch in midwinter and the second, on average, 24 days after the offspring from the first brood left the nest.     

Evidence for correlation between mutability of an unstable anthocyanin-governing locus and abundance of anthocyanin

Summary The pal-rec gene of Antirrhinum majus suppresses anthocyanin except in those cell lines where pal-rec has mutated to Pal, so that anthocyanin-coloured flecks appear on whitish petals. Antirrhinum majus families of very high and very low anthocyanin content (Dark and Pale) were obtained and crossed with two pal-rec pal-rec lines, one with consistently high and the other consistently low mutability. Mutable offspring from Dark parents tended to show higher mutability than those from Pale parents in crosses with either mutable line, providing evidence for an association between intense pigmentation and high mutability. Such an association is discussed in the context of relationship between precursor availability for conversion by a gene product and initiation of activity of that gene.     

Pale Rock Sparrow Carpospiza brachydactyla in the Mount Lebanon range: modelling breeding habitat

The Pale Rock Sparrow Carpospiza brachydactyla is a poorly known species with very little documentation of its breeding habitat preferences. Using detailed surveys and habitat modelling for a population in southern Lebanon's Bekaa valley, we have identified aspects of the habitat associated both temporally and spatially with breeding. Static spatial habitat modelling using three fundamentally different statistical techniques (multiple linear regression, regression trees and artificial neural networks) agreed on positive associations of breeding density with 'pebbliness' of ground cover and the quantity of available habitat, and a negative association with trees. Temporal associations were found between breeding and a rise in temperature and peaks in grasshopper and beetle abundance, the two main prey that we observed the birds taking. These findings are discussed in the context of Pale Rock Sparrow conservation and implications for species-directed habitat assessment more generally.     

A phylogenetic analysis of Pseudonaja (Hydrophiinae, Elapidae, Serpentes) based on mitochondrial DNA sequences

A phylogenetic analysis of mitochondrial ND4 and adjacent tRNA sequences for a geographically extensive series of specimens reveals nine major clades within Pseudonaja, of which six are largely coincident with nominal taxa (P. affinis, P. guttata, P. inframacula, P. ingrami, P. modesta, and P. textilis). The remaining three clades are composed of specimens presently referred to P. nuchalis. Two of these clades correspond with the "Darwin" and "Southern" morphs of previous authors, while the third clade incorporates the "Orange with black head" and "Pale head, grey nape" morphs. We are unable to confirm the presence of consistent karyotypic differences between "Orange with black head" and "Pale head, grey nape" specimens, however, P. inframacula, P. textilis, and P. nuchalis "Darwin" are found to exhibit distinctive karyotypes, as previously reported. These results, in conjunction with additional observations of karyotpic and morphological variation, are consistent with nine historically-independent lineages (i.e., species) within Pseudonaja. There is strong support for a clade composed of P. affinis, P. inframacula, P. ingrami, P. textilis, and the three P. nuchalis lineages, and for the relationships (P. inframacula, P. nuchalis "Southern") and (P. nuchalis "Darwin", P. nuchalis "Orange with black head"--"Pale head, grey nape" ).     

Novel media for detection of microbial producers of cellulase and xylanase

Abstract Agar nutrient media containing 0.2% soluble hydroxyethylcellulose covalently dyed with Ostazin Brilliant Red H-3B or soluble beechwood 4-O-methyl- d -glucurono- d -xylan dyed with Remazol Brilliant Blue R were used for sensitive detection of microorganisms producing and secreting into the surrounding medium endo-1,4-β-glucanase and/or endo-1,4-β-xylanase. Pale clearing zones formed around the colonies grown on such media indicated the production of corresponding polysaccharide-hydrolases.     

The relative influence of prey abundance and co-breeders on the reproductive performance of polyandrous Pale Chanting-goshawks

This study investigates if the reproductive performance of polyandrous Pale Chanting-goshawks, Melierax canorus, is governed by the abundance of dominant rodent-prey species or a co-breeding male participating fully in prey being delivered to the female and young. Polyandrous trios in prey-rich habitat, the only habitat where these trios occurred, failed to produce more offspring than monogamous pairs, but attempted more second broods in years of high prey abundance. The higher the prey-delivering rates at the nesting sites by either one monogamous male or two polyandrous males (combined effort), the higher the proportion of time their females spent in close proximity to the nest. Since there were no significant differences between the body masses of nestlings fledged by polyandrous and monogamous groups, higher delivery rates relieved females from away-from-the-nest hunting duties and permitted them to feed on prey not fed to offspring. Although breeding in polyandrous trios held fitness benefits for females, e.g. to accumulate the necessary body reserves for laying a second clutch in years of high prey abundance, it is still not clear how males benefited. The reproductive performance of each group was strongly linked to the abundance of the dominant, otomyine rodent prey (Otomys unisulcatus and Parotomys brantsii) and it was therefore prey abundance, and not the number of males delivering prey to the female and nestlings at each nesting site, that controlled the reproductive performance of cooperative-breeding Pale Chanting-goshawks.     

Negative effect of ayu on the growth of omnivorous pale chub in experimental pools

The growth rate of pale chub Zacco platypus was negatively correlated with the number and biomass of ayu Plecoglossus altivelis in experiment pools regardless of their body weight. Both species were omnivorous, feeding upon both benthic algae and invertebrates; ayu fed principally upon algae whereas pale chub consumed invertebrates. Pale chub shifted their moving tactics from bottom moving to surface moving or sit-and-wait when they coexisted with numerous ayu, presumably due to occasional attack by ayu. It seems likely that the reduced pale chub growth rate was due to interspecific aggression and exploitation of benthic algae and invertebrates by ayu.     

A minor species of a type I casein kinase from yeast phosphorylating threonine residues of protein substrate

Protein kinase of Mr 23 000 was isolated from yeast and purified to apparent homogeneity. The enzyme preferentially phosphorylated casein and phosvitin in the presence of ATP as a phosphoryl donor. Its activity was neither affected by cyclic nucleotides nor by heparin. The kinase displayed practically the same substrate specificity as a typical casein kinase I from yeast (Kudlicki, W., Szyszka, R., Paleń, E. and Gasior, E. (1980) Biochim. Biophys. Acta 633, 376-385) except that it phosphorylated threonine instead of serine residues in protein substrates.     

The pale brown allele in Cepaea nemoralis

The pale brown colour morph in Cepaea nemoralis appears to be determined by an allele at the C (colour) locus ( C ^{P B}). Pale brown is dominant to yellow, codominant with pink and recessive to dark brown. It is linked to the B locus (which controls the presence or absence of banding on the shell), but not to the U locus, which determines whether there is one band or five. In segregations of pale brown and yellow there is a significant deficiency of pale brown, suggesting that there are differences in viability between the morphs.     

Der Chlorophyllgehalt von Tumoren an bleichem und grünem Blattgewebe von Kalanchoe fedtschenkoi

Summary Pale and green leaves of Kalanchoe fedtschenkoi var. variegata were inoculated with Agrobacterium tumefaciens. Six weeks later the chlorophyll contents of the leaves and their tumors were investigated. The tumor tissues possess very similar concentrations of chlorophylls and a low number of chloroplasts per cell. Thereby they differ from each of the initial tissues. The qualitative composition of pigments (chlorophylls and carotenoids) of the 4 tissues is the same.     

北京地区宽鳍鱲的早期发育

作者对分布于北京市怀柔区怀九河的宽鳍鱲(Zacco platypus)的胚胎发育及仔鱼前期发育进行了研究,过程中采用人工干法授精获取受精卵, 观察并描述了宽鳍鱲早期发育过程及其特点。结果显示, 宽鳍鱲成熟卵呈圆球状, 平均卵径1.04 mm, 为沉性卵。在平均23.0℃(17.1-28.0℃)水温条件下, 从受精卵到孵化经历了73h1min, 积温为1682.3 度时; 孵化后6.5d 进入弯曲期仔鱼。仔鱼前期发育速度与出膜前相比明显减慢;弯曲期仔鱼出现大量死亡可能与有限的人工培育条件、混合营养期能量供给不足等原因有关。通过比较发现, 宽鳍鱲与鲤科中其他21 个种相比, 早期发育时间比其中7 个种均长。宽鳍鱲早期发育时间比同域分布、相同发育水温的马口鱼略长, 明显长于同属的纵纹鱲的发育时间。宽鳍鱲南、北方种群仔鱼发育速度存在差异, 北方种群出膜前发育速度比南方种群快, 但出膜后发育速度减慢。       

Pale coloration in Aphis fabae reared on beans treated with the plant growth regulator,ethylene-bis-nitrourethane

Aphis fabae reared on broad bean plants treated with the experimental growth stimulator ethylene-bis-nitrourethane were extremely pale in colour and this persisted for the life of the individual, even when first instar nymphs were transferred from treated to untreated plants. Pale aphids had less than half the amounts of the pigments protoaphin and aphinin that were present in normal aphids. It is concluded that the aphids probably received a compound which inhibited pigment formation from the treated plants; the chelating properties of the metabolite of the compound in plants are consistent with this conclusion.     

The paleobiology of two adult skeletons from Baousso da Torre (Bausu da Ture) (Liguria,Italy): Implications for Gravettian lifestyle

This article presents the main skeletal characteristics of the two largely unpublished Gravettian adult skeletons from Baousso da Torre (Liguria, Italy). BT1 and BT2 were two adult tall males, who died aged respectively between 20 and 50 years, and between 20 and 30 years. Their body proportions fall within the range of variation known for the middle Upper Paleolithic, and their skeletal remains are characterized by considerable osteometric values, which fall consistently in the upper part of the Upper Paleolithic male sample variation. They show a high degree of upper limb lateralization, implying that they were likely involved in strenuous and/or repetitive unimanual tasks. They also exhibit very robust lower limbs, likely related to repeated long-distance travels in mountainous terrains. These results are in total agreement with previous hypotheses on Late Pleistocene population behavioral patterns.     

Varietal Resistance of Flax to Disease

Field experiments, using contaminated seed, have been carried out from 1941 to 1947 to study the reaction of a wide range of both fibre and oil varieties of Linum usitatissimum to attack by Polyspora Lini Laff., Colletotrichum linicola Pethybr. & Laff., Phoma sp. and Melampsora Lini (Ehrenb.) LéV. The tests made with Colletotrichum linicola were supplemented by direct inoculation experiments with young seedlings grown under greenhouse or laboratory conditions.
None of the varieties tested proved to be immune to attack by Polyspora Lini, Colletotrichum linicola or Phoma sp. Herkules, Concurrent, Hindi, La Plata, Saginaw x Ottawa 770 B and Winona x Ottawa 770 B were resistant to the stem-break and browning phases of attack by Polyspora Lini ; Bison, Hindi and La Plata were resistant to attacks by Colletotrichum linicola , while Hindi and La Plata showed some resistance to Phoma sp. Immunity or a 'high' measure of resistance to attack by Melampsora Lini was exhibited by Formosa, Stakhanovets, Textilshchik, U.S.S.R. No. 2 (ex Dugejheshchya), Wada, Argentine Selection (C.I. 112), Baladi, Bolley Golden (C.I. 644), Bombay (C.I. 42), Hindi, Italia Roma (C.I. 1005–2), J.W.S. (C.I. 708–1), Koto (C.I. 872), Kenya (C.I. 709–1), La Plata, Newland (C.I. 188), Ottawa 770B (C.I. 355), Pale Blue Crimped (C.I. 647), Tammes Pale Blue (C.I. 333–1), Williston Golden (C.I. 25–1) and C.I. 836.
All varieties did not show the same reactions to stem-break as to the browning phase of attack by Polyspora Lini and similar differences were noted in the case of the uredospore and teleutospore stages of Melampsora Lini. In certain varieties the stems showed a greater resistance to attack by Polyspora Lini or Melampsora Lini than the leaves.
Seeds of all varieties tested in the field experiments became heavily attacked with Polyspora Lini (except in La Plata), Colletotrichum linicola and Phoma sp.     

A dedicated reserve for conservation of two species of Synemon (Lepidoptera: Castniidae) in Australia

Introductory notes on the family Castniidae are followed by some general information on the Pale Sun-moth, Synemon selene (Klug 1850) and the Golden Sun-moth, Synemon plana (Walker 1854). An account is given of the discovery of an extant population of the Nhill Morph of S. selene. The remainder of this work documents steps that have been taken to establish a 4.5 ha reserve at Nhill in western Victoria, to meet the urgent conservation needs of this taxon and asympatrically occurring population of S. plana. Some management issues that concern these two grassland-dependent Synemon species at Nhill are also discussed.     

Genetic depletion at adaptive but not neutral loci in an endangered bird species

Many endangered species suffer from the loss of genetic diversity, but some populations may be able to thrive even if genetically depleted. To investigate the underlying genetic processes of population bottlenecks, we apply an innovative approach for assessing genetic diversity in the last known population of the endangered Pale‐headed Brushfinch (Atlapetes pallidiceps) in Ecuador. First, we measure genetic diversity at eleven neutral microsatellite loci and adaptive SNP variation in five Toll‐like receptor (TLR) immune system genes. Bottleneck tests confirm genetic drift as the main force shaping genetic diversity in this species and indicate a 99 % reduction in population size dating back several hundred years. Second, we compare contemporary microsatellite diversity with historic museum samples of A. pallidiceps, finding no change in genetic diversity. Third, we compare genetic diversity in the Pale‐headed Brushfinch with two co‐occurring‐related brushfinch species (Atlapetes latinuchus, Buarremon torquatus), finding a reduction of up to 91% diversity in the immune system genes but not in microsatellites. High TLR diversity is linked to decreased survival probabilities in A. pallidiceps. Low TLR diversity is thus probably an adaptation to the specific selection regime within its currently very restricted distribution (approximately 200 ha), but could severely restrict the adaptive potential of the species in the long run. Our study illustrates the importance of investigating both neutral and adaptive markers to assess the effect of population bottlenecks and for recommending specific management plans in endangered species.     

马尾松成熟合子胚的体细胞胚胎发生和植株再生

采用马尾松（Ｐｉｎｕｓｍ ａｓｓｏｎｉａｎａ Ｌａｍ ｂ．）成熟合子胚为起始外植体,在含２,４－Ｄ １０ ｍ ｇ／Ｌ,ＫＴ和ＢＡ 各４ ｍ ｇ／Ｌ的ＤＣＲ培养基上得到胚发生培养物。将白色半透明的愈伤组织（含早期原胚）在含２,４－Ｄ１．０ ｍ ｇ／Ｌ,ＫＴ和ＢＡ 各０．４ ｍ ｇ／Ｌ的ＤＣＲ培养基上保持并增殖。在附加９０００ ｍ ｇ／Ｌ肌醇的ＤＣＲ高渗培养基上得到粗壮的后期原胚。ＡＢＡ 和活性炭同时使用能促进子叶胚的形成,最高频率为３５．１％ 。在无激素培养基上,成熟体细胞胚萌发并进一步形成完整小植株     

Somatic Embryogenesis and Plantlet Regeneration from Callus of Mature Zygotic Embryos of Masson Pine

Embryogenic cultures were initiated from mature zygotic embryos of masson pine (Pinus massoniana Lamb. ) on DCR medium supplemented with 2, 4-D 10 mg/L, KT and BA each at 4 mg/L. Pale and translucent calli with early stage proembryos were maintained and multiplicated on DCR medium supplemented with 2, 4-D 1.0 mg/L KT and BA each at 0.4 mg/L. Robust late-stage proembryos were obtained when the calli were cultured on DCR medium containing 9000 mg/L myo-inositol. Abscisic acid and activated charcoal promoted the formation of cotyledonary embryos at the highest frequency of 35.1 %. Mature somatic embryos could germinate and develop further into plantlets when they were isolated and cultured on a hormone-free DCR medium.