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1.
A new albinistic allele in the cat is described and designated blue-eyed albino (symbol c a ). The coat is completely white. The eyes possess a dull red pupil in reduced light and a pale translucent blue iris. Reasons are given for regarding the allele as less extreme than complete albinism. The inheritance of three members of the albino series in the cat has now been reported. In decreasing order of dominance these are full colour (C), Burmese (c b ), Siamese (c s ) and blue-eyed albino (c a ).  相似文献   

2.
A new class of albino mutant ofCochliobolus heterostrophus was isolated. Its colony color was indistinguishable from that of albino mutants previously reported. Application of the melanin intermediate scytalone induced this mutant to pigment slightly, but not completely. Genetic analyses showed that the mutant had two deficient genes. When only one of these genes was deficient, the colony color was indistinguishable from the wild type, whereas deficiency of both genes resulted in the albino phenotype. These deficiencies lie upstream of scytalone biosynthesis. These genes were designated asCal1 andCal2.  相似文献   

3.
To our knowledge, this paper is the first record/report of a juvenile light-coloured Weddell seal (Leptonychotes weddellii) at Cape Shirreff, Livingston Island in January 1998, determining that it was an albino individual. Based on available literature, three cases of albino seals have been reported exclusively for Harbour seal pups, and no albino has been reported for Antarctic pagophilic true seals. Therefore, this is the first confirmed case of albinism in Antarctic pagophilic true seals species, indicating that this phenomenon is indeed of a rare occurrence.
Daniel TorresEmail:
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4.
In the albino mutant of an Okinawa strain of Locusta migratoria (L.) (Orthoptera: Acrididae), albinism is caused by the absence of the dark‐colour‐inducing neurohormone (DCIN), which is present in the corpora cardiaca (CC) of normally coloured phenotypes. This study tests whether the absence of DCIN is responsible for albinism in an albino mutant of another locust, Schistocerca gregaria (Forsk.) (Orthoptera: Acrididae). This seemed feasible because a single Mendelian unit controls albinism in both species. However, implantation of CC, or injection of an extract of CC, from albino donors of S. gregaria, induce dark coloration in crowded nymph recipients of the Okinawa albino mutant of L. migratoria, as effectively as do implanted CC, or injections of extract of CC, from normal phenotype donors of S. gregaria. Therefore, DCIN is present in the albino mutant of S. gregaria, and consequently, the albinism in this mutant is not caused by its absence. Implantation of CC, or injection of extracts of CC, from albino donors of S. gregaria to conspecific albino nymphs does not induce darkening. Only extremely high doses of synthetic DCIN injected into albino nymphs of S. gregaria are effective, inducing some darkening. The dose to induce such darkening in albino nymphs of S. gregaria is 50 nmol, ≈ 5 × 106 times higher than that (10 femtomol) needed to induce equivalent darkening in nymphs of the Okinawa albinos of L. migratoria. The results are discussed and some possible explanations of the observed effects outlined.  相似文献   

5.
A specimen of the rare squid genus Octopoteuthis (Cephalopoda: Octopoteuthidae) from 1600 m in the Sardinian Channel (central western Mediterranean) is described. Meristic and morphological data are provided. The specimen was a spent female and details of the reproductive system and implanted spermatangia are reported. Genetic analysis of this specimen and comparison with those available for species in this genus were carried out. Due to issues associated with the taxonomy of the genus Octopoteuthis, it was not possible to identify the specimen to the species level. The taxonomy of the genus is discussed.  相似文献   

6.
A report is given of an adult caecilian, Scolecomorphus kirkii, found in the gut of a specimen of the snake Atractaspis aterrima from the Udzungwa Mountains, Tanzania. Both predator and prey are largely fossorial in soil, and their ecology is poorly known, such that this is the first reported predator of any scolecomorphid caecilian. The caecilian was ingested head first and much of the flesh from the anterior of the specimen had been digested. The prey/predator mass ratio is 0.48. This value is substantially higher than reported for A. aterrima from West Africa, and refutes the notion that this species feeds only on small prey. Most reported predators of caecilians are snakes, and a brief review is presented.  相似文献   

7.
In an analysis of 339 independent T 0 transgenic rice lines generated by Agrobacterium-mediated transformation, albino plants appeared in the T 1 generation in two single-copy transgenic lines, O54 and O36 and in one double-copy transgenic line, C18. While the T 0 plants of these three lines were green, albino and green plants emerged in a 1:3 ratio in the T 1 generation. The albino phenotype segregated as a monogenic recessive trait. Southern blot analysis of the green and albino plants in the T 1 generation confirmed that the albino trait and the T-DNA insertion events were unlinked. Segregation of the albino trait from the transgenic trait in the lines O54 and O36 was confirmed in T 2 and T 3 generations, respectively. Homozygous transgenic plants free from the albino trait were also identified. In the double-copy transgenic line C18, we genetically separated the two transgenic loci, out-segregated the albino locus from both transgene loci, and identified homozygous plants for each of the transgenic events by Southern blot analysis in the T 1 generation itself. Thus, we demonstrate that when an albino trait appears in the T 1 generation and is unlinked to a transgene locus, the albino locus can be segregated from the transgene locus and homozygous transgenic lines free from albinos can be established.  相似文献   

8.
Strial melanocytes are required for normal development and correct functioning of the cochlea. Hearing deficits have been reported in albino individuals from different species, although melanin appears to be not essential for normal auditory function. We have analyzed the auditory brainstem responses (ABR) of two transgenic mice: YRT2, carrying the entire mouse tyrosinase (Tyr) gene expression-domain and undistinguishable from wild-type pigmented animals; and TyrTH, non-pigmented but ectopically expressing tyrosine hydroxylase (Th) in melanocytes, which generate the precursor metabolite, L-DOPA, but not melanin. We show that young albino mice present a higher prevalence of profound sensorineural deafness and a poorer recovery of auditory thresholds after noise-exposure than transgenic mice. Hearing loss was associated with absence of cochlear melanin or its precursor metabolites and latencies of the central auditory pathway were unaltered. In summary, albino mice show impaired hearing responses during ageing and after noise damage when compared to YRT2 and TyrTH transgenic mice, which do not show the albino-associated ABR alterations. These results demonstrate that melanin precursors, such as L-DOPA, have a protective role in the mammalian cochlea in age-related and noise-induced hearing loss.  相似文献   

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11.
Genetic studies and quantitative determination of levels of 3-hydroxykynurenine and kynurenine were performed in an albino strain of a terrestrial isopod Armadillidium vulgare. From the results of matings between the albino and the albino, the red, the dark red, or the wild type individuals, the albino A. vulgare seems to be regulated by an autosomal gene(s) recessive to its wild allele. Litter mating of F1 progenies obtained by crossing the albino and the red mutant or the albino and the dark red mutant yielded progenies at a ratio of 3:6:3:4 for the red, the dark red, the wild, and the albino phenotypes, respectively. The albino gene(s) seems not to be allelic but to be epistatic to the red gene(s) with respect to ommochrome biosynthesis. Quantitative determination of 3-hydroxykynurenine carried out by high-performance liquid chromatography with electrochemical detection revealed that the 3-hydroxykynurenine content in the albino was significantly lower than that in the wild or the red type. The whole content of 3-hydroxykynurenine after enzymatic conversion of kynurenine to 3-hydroxykynurenine was still considerably lower than that found in the wild type, even though it increased after the conversion. The albino gene(s) seems to be associated with a blockage at distinct level(s) of ommochrome biosynthesis.  相似文献   

12.
13.
A new specimen of the rare fossil bee Thaumastobombus andreniformis Engel 2001 (Apidae: Apinae: Electrapini) is reported and figured from middle Eocene (Lutetian) Baltic amber. The new specimen, a female of the worker caste, agrees in every respect with the holotype except some morphometric differences. These minor size differences are likely related to the degree of sociality of T andreniformis.  相似文献   

14.
Albinism in the sea cucumber Apostichopus japonicus (Selenka) may be a significant biomarker that can be used to obtain information about behaviors and growth of this species. The goal of this study was to compare the behaviors and growth rate between albino and normal A. japonicus. Total light intensity and specific growth rate were used as statistical indices. Diverse light intensities were tested in the laboratory and in the field to identify ecological characteristics of albino A. japonicus. Experimental results revealed that: (1) both albino and normal specimens had negative phototaxis; (2) normal A. japonicus were more responsive to intense light than albino species, and the latter could withstand longer periods of exposure to intense light; (3) normal A. japonicus grew faster than albino specimens; and (4) both normal and albino A. japonicus grew faster in natural light than in the other light intensities tested.  相似文献   

15.
Some green orchids obtain carbon from their mycorrhizal fungi, as well as from photosynthesis. These partially mycoheterotrophic orchids sometimes produce fully achlorophyllous, leaf‐bearing (albino) variants. Comparing green and albino individuals of these orchids will help to uncover the molecular mechanisms associated with mycoheterotrophy. We compared green and albino Epipactis helleborine by molecular barcoding of mycorrhizal fungi, nutrient sources based on 15N and 13C abundances and gene expression in their mycorrhizae by RNA‐seq and cDNA de novo assembly. Molecular identification of mycorrhizal fungi showed that green and albino E. helleborine harboured similar mycobionts, mainly Wilcoxina. Stable isotope analyses indicated that albino E. helleborine plants were fully mycoheterotrophic, whereas green individuals were partially mycoheterotrophic. Gene expression analyses showed that genes involved in antioxidant metabolism were upregulated in the albino variants, which indicates that these plants experience greater oxidative stress than the green variants, possibly due to a more frequent lysis of intracellular pelotons. It was also found that some genes involved in the transport of some metabolites, including carbon sources from plant to fungus, are higher in albino than in green variants. This result may indicate a bidirectional carbon flow even in the mycoheterotrophic symbiosis. The genes related to mycorrhizal symbiosis in autotrophic orchids and arbuscular mycorrhizal plants were also upregulated in the albino variants, indicating the existence of common molecular mechanisms among the different mycorrhizal types.  相似文献   

16.
朱学泰  杜璠  冶晓燕  范佳馨  蒋长生 《广西植物》2022,42(10):1762-1766
该文通过形态特征研究和基于ITS序列的分子系统学分析,对采自甘肃省连城国家级自然保护区的1份形态特殊的胶瘤菌属标本进行分类学研究。结果表明:该标本是孔生胶瘤菌(新拟)(Carcinomyces polyporina),隶属于担子菌门(Basidiomycota)、银耳纲(Tremellomycetes)、银耳目(Tremellales)、胶瘤菌科(新拟)(Carcinomycetaceae)。该物种代表了中国的1个新记录属、种,是该属在东亚地区的首次报道。孔生胶瘤菌寄生于多孔菌类真菌的子实体上,形成胶质状菌瘿,担子纵裂,担孢子可萌发后形成分生孢子。研究标本保存于中国科学院昆明植物研究所标本馆隐花植物标本室,馆藏号为HKAS 115765。  相似文献   

17.
The nonchlorophyllous (albino) tissue of mature C. blumei leaves is a sink for photoassimilate. Transport from the green to the albino region of the same leaf was inhibited by cold and anoxia. When the green tissue of mature leaves was removed, the remaining albino portion imported labeled translocate from other mature leaves in the phloem. Photoassimilate unloading in the albino region of mature leaves was studied by quantitative autoradiography. The unloading was inhibited by cold but not by anoxia. No labeled photoassimilate could be detected in the free space of mature albino tissue by compartmental efflux analysis as phloem unloading proceeded in a N2 atmosphere, indicating that unloading, may occur by a symplastic pathway as it apparently does in sink leaves of other species. The minor veins of mature albino leaf tissue did not accumulate exogenous [14C]sucrose. Minor veins of green tissue in the same leaves accumulated [14C]sucrose but, in contrast to other species studied to date, this accumulation was insensitive to the inhibitor p-chloromercuribenzensulfonic acid (PCMBS).In its capacity to import and unload photoassimilate, and in the inability, of the minor veins to accumulate exogenous sucrose, the albino region of the mature C. blumei lamina differs from mature albino tobacco leaves and darkened mature leaves of other species. This, together with evidence indicating that phloem loading in C. blumei and other species may occur by different routes and with different sensitivity to PCMBS, indicates that the mechanism of transfer of photoassimilates between veins and surrounding tissues, and the mechanism of the sink-source transition, may not be the same in the leaves of all species. It is speculated that the unusual properties of the C. blumei leaf may be a consequence of the presence, in the minor veins, of intermediary cells, large companion cells connected to the bundle sheath by abundant plasmodesmata.Abbreviation PCMBS p-chloromercuribenzenesulfonic acid  相似文献   

18.
Lysenko V 《Planta》2012,235(5):1023-1033
Residual chlorophyll in chlorophyll-deficient (albino) areas of variegated leaves of Ficus benjamina originates from guard cell chloroplasts. Photosynthetic features of green and albino sectors of F. benjamina were studied by imaging the distribution of the fluorescence decrease ratio Rfd within a leaf calculated from maximum (Fm) and steady-state leaf chlorophyll fluorescence (Fs) at 690 and 740 nm. Local areas of albino sectors demonstrated an abnormally high Rfd740/Rfd690 ratio. Fluorescence transients excited in albino sectors at red (640 and 690 nm) wavelengths showed an abrupt decrease of the Rfd values (0.4 and 0.1, correspondingly) as compared with those excited at blue wavelengths (1.7–2.4). This “Red Drop” was not observed for green sectors. Normal and chlorophyll-deficient leaf sectors of F. benjamina were also tested for linear and cyclic electron transport in thylakoids. The tests have been performed studying fluorescence at a steady-state phase with CO2-excess impulse feeding, photoacoustic signal generated by pulse light source at wavelengths selectively exciting PSI, fluorescence kinetics under anaerobiosis and fluorescence changes observed by dual-wavelength excitation method. The data obtained for albino sectors strongly suggest the possibility of a cyclic electron transport simultaneously occurring in guard cell thylakoids around photosystems I and II under blue light, whereas linear electron transport is absent or insufficient.  相似文献   

19.
Impaired spatial learning is a prominent deficit in fragile X syndrome (FXS). Previous studies using the Fmr1 knockout (KO) mouse model of FXS have not consistently reported a deficit in spatial learning. Fmr1 KO mice bred onto an albino C57BL/6J‐Tyrc‐Brd background showed significant deficits in several primary measures of performance during place navigation and probe trials in the Morris water maze. Fmr1 KO mice were also impaired during a serial reversal version of the water maze task. We examined fear conditioning as an additional cognitive screen. Knockout mice exhibited contextual memory deficits when trained with unsignaled shocks; however, deficits were not found in a separate group of KO mice trained with signaled shocks. No potentially confounding genotypic differences in locomotor activity were observed. A decreased anxiety‐like profile was apparent in the open field, as others have noted, and also in the platform test. Also as previously reported, startle reactivity to loud auditory stimuli was decreased, prepulse inhibition and social interaction increased in KO mice. Female Fmr1 KO mice were tested along with male KO mice in all assays, except for social interaction. The female and male KO exhibited very similar impairments indicating that sex does not generally drive the behavioral symptoms of the disorder. Our results suggest that procedural factors, such as the use of albino mice, may help to reliably detect spatial learning and memory impairments in both sexes of Fmr1 KO mice, making it more useful for understanding FXS and a platform for evaluating potential therapeutics.  相似文献   

20.
通过标本考证和野外研究,证实中国文献记载的纤细蛇根草(Ophiorrhiza gracilis Kurz)实为尾瓣蛇根草(O. caudipetala Deb & Monda)错误鉴定,而后者之前仅被报道分布于印度,因此为中国新记录。尾瓣蛇根草具有明显不等大的对生叶片, 花冠裂片背部具长0.6~1 mm的角状突起,易与中国蛇根草属其它种类区分。  相似文献   

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