Ultra-violet photoreceptors in the animal kingdom: their distribution and function

Until very recently, the role of ultra-violet (UV) colour perception in vertebrate and invertebrate vision has largely been ignored. However, in the past few years, a host of detailed information has become available on the widespread distribution of UV receptors in different species - from insects to mammals - and the important functions they seem to play in navigation, foraging, intraspecies communication and the control of circadian rhythms.     

Comparative chromosome painting between two marsupials: origins of an XX/XY1Y2 sex chromosome system

Cross-species chromosome painting was used to investigate genome rearrangements between tammar wallaby Macropus eugenii (2n = 16) and the swamp wallaby Wallabia bicolor (2n = 10♀/11♂), which diverged about 6 million years ago. The swamp wallaby has an XX female:XY₁Y₂ male sex chromosome system thought to have resulted from a fusion between an autosome and the small original X, not involving the Y. Thus, the small Y₁ should represent the original Y and the large Y₂ the original autosome. DNA paints were prepared from flow-sorted and microdissected chromosomes from the tammar wallaby. Painting swamp wallaby spreads with each tammar chromosome-specific probe gave extremely strong and clear signals in single-, two-, and three-color FISH. These showed that two tammar wallaby autosomes are represented unchanged in the swamp wallaby, two are represented by different centric fusions, and one by a tandem fusion to make the very long arms of swamp wallaby Chromosome (Chr) 1. The large swamp wallaby X comprises the tammar X as its short arm, and a tandemly fused 7 and 2 as the long arm. The acrocentric swamp wallaby Y₂ is a 2/7 fusion, homologous with the long arm of the X. The small swamp wallaby Y₁ is confirmed as the original Y by its painting with the tammar Y. However, the presence of sequences shared between the microdissected tammar Xp and Y on the swamp wallaby Y₂ implies that the formation of the compound sex chromosomes involved addition of autosome(s) to both the original X and Y. We propose that this involved fusion with an ancient pseudoautosomal region followed by fission proximal to this shared region. Received: 16 October 1996/Accepted: 30 January 1997     

Physiologic regulation of mixtalol in rape senescence and its yield effects

Physiologic and yield effects of mixtalol at various concentrations sprayed on rape at the anthesis stage were examined. Foliar sprays of 4 and 2 ppm mixtalol significantly increased the chlorophyll content of rape leaves and pods, reduced the accumulation of malondialdehyde and ethylene production, and delayed the degradation of superoxide dismutase and catalase activities of the rape plant. Mixtalol also increased root oxidizability. Meanwhile, the number of branches and pods per plant was increased, and a 10.7% and 8.2% increase of seed yield over the controls was observed with treatments of 4 and 2 ppm mixtalol, respectively. No significant effects from mixtalol were observed on the maturation of plants or on the seed oil content or the erucic acid and glucosinolate content. Total rape oil production increased with 4 and 2 ppm mixtalol significantly by 12.4% and 10.5%, respectively, over the controls.Abbreviations MTL mixtalol - MDA malondialdehyde - TBA thiobarbituric acid - SOD Superoxide dismutase - CAT catalase - TTC tetrazolium     

Two cDNA clones coding for the legumin protein of Pisum sativum L. contain sequence repeats

The sequence of two cDNA clones coding for the whole of the -subunit and most of the -subunit of legumin are presented together with a considerable amount of protein sequence data to confirm the predicted amino acid sequence. A unique feature shown by these cDNAs is the presence of three 56 base pair tandem repeats in the region encoding the C terminal of the polypeptide. The tandem repeats are also exhibited in the predicted polypeptide sequence as three 18 amino acid repeats which contain extremely high proportions of polar, mainly acidic, residues. The new sequences are compared to the previously published sequence of some shorter legumin cDNAs (Nature 295: 76–79). In the region where the sequences overlap, the previous cDNAs differ from the new ones by only a few base substitutions but most of the repeated region is not present though the sequences on either side are. The possibility that the absence of the repeats may reflect the difference between two types of legumin gene, rather than an artefact of the cloning of the cDNAs, is discussed.     

Pelvic visceral arteries of rabbits (Oryctolagus cuniculus)]

40 pelvic preparations of rabbits (oryctolagus cuniculus) were bilaterally studied by dissection under the stereomicroscope and angiography. The arterial pattern of the pelvis, i.e. origin and branching of the umbilical, urogenital and internal pudendal arteries (visceral branches), is described. The main characteristics observed are as follows: (1) The umbilical artery is permeable in adults and gives origin to the cranial vesical artery and a caudal branch that irrigates the pelvic urogenital organs and, eventually, the rectum, with six patterns of branching in both sexes. (2) Usually, the urogenital artery is the continuation of the visceral branch of the internal iliac artery. In 1 animal, unilaterally, it arises from the median sacral artery. In 12 animals (6 bilaterally and 6 unilaterally) the urogenital artery is absent. When present, it forms two branches, a cranial and a caudal one, that irrigate of the urogenital organs in both sexes. (3) The internal pudendal artery is the direct continuation of the internal iliac artery and gives to rise to some visceral branches that irrigate the penis, bulbourethral gland and rectum (with six patterns of branching) in males, and the vagina, clitoris and rectum (with three patterns of branching) in females.     

Deoxyribonucleic acid synthesis and deoxyribonucleic acid-polymerase activity during early germination of wheat embryos at high and low viability

³H-thymidine incorporation and DNA-polymerase activity during early hours of wheat embryo germination at two viability levels have been studied. The patterns of two biosynthetic activities, as well as the dependence of DNA synthesis on protein synthesis, indicated the presence of a delay in the early phase of imbibition of the aged embryos with respect to viable germs.     

Sialyl-transferase mitochondriale

A sialyl transferase activity is found in purified mitochondria. It is not due to residual contamination and this enzymatic system is located in the outer mitochondrial membrane. This proves mitochondrial autonomy in regard to glycoconjugate sialylation.