Occurrence of rye (Secale cereale) 350-family DNA sequences inAgropyron and otherTriticeae

Evidence is presented that in the R and P genomes (Secale cereale andAgropyron cristatum, respectively) of theTriticeae there exist closely related 350-family DNA sequences in the terminal heterochromatin. This observation is compared to the relationships between these two genomes derived from a comparison of theNor and5 S DNA loci as well as the available data on morphological characters, chromosome pairing, and isozyme studies. It is concluded that the R and P genomes are not closely related and that the common presence of very similar 350-family DNA sequences reflects the parallel amplification of this family of DNA sequences.     

Frequent duplication and deletion events in the 5S RNA genes and the associated spacer regions of theTriticeae

The 5 S DNA units from 15 grasses in theTriticeae were analysed at the DNA sequence level. Four units carried duplications near the 3-end of the 5 S RNA gene with 3 of the duplications centred on the same base pairs as a duplication previously reported byGerlach & Dyer. The fourth duplication was located 3 downstream from the gene, in the spacer region. Apparent deletions were very frequent when units of the different grasses were compared and it was clear that these deletions did not extend into a 75 bp spacer region upstream from the 5 S RNA gene. This 75 bp region also tended to be more conserved between the grasses as compared to the high level of sequence change in the rest of the spacer region. — Phenetic relationships were established between the grasses using the sequence data. The relationships were generally consistent with the data from other parameters and, in addition, showed that two Australian grasses were closely related to the other Northern hemisphere genera examined. The data concerning the Australian grasses is discussed in relation to the isolated nature of Australia.     

Intergeneric relationships ofLolium,Festuca, andVulpia (Poaceae) and their phylogeny

Morphological and seed protein analyses of 26 species of the generaLolium, Festuca andVulpia confirmed their close systematic affinities. Six inflorescence characters readily differentiatedFestuca fromLolium. Protein similarities betweenFestuca of sect.Bovinae and cross-pollinated species ofLolium, coupled with cytogenetic and crossability data, substantiate that they should be united into one genus.Vulpia had phenetic similarities with sect.Scariosae, Montanae andOvinae ofFestuca. Lolium, Festuca, andVulpia are most likely derived from a common ancestral form which was close toFestuca pratensis andLolium perenne.     

Differential regulation of Ultrabithorax in two germ layers of Drosophila

The homeotic gene Ultrabithorax (Ubx) is expressed in specific parts of Drosophila embryos: in a single metamer in the visceral mesoderm and forming a complex pattern limited to a broad domain in the ectoderm and in the somatic mesoderm. Here we use a linked beta-galactosidase gene to identify cis-acting regulatory sequences. In the visceral mesoderm, correct expression of Ubx depends on localized upstream sequences. In the ectoderm, all galactosidase-positive transformants show the same characteristic pattern. The repeated elements of this basal pattern appear to be a sub-pattern of engrailed (en) expression; they depend on en function as well as on sequences in the Ubx RNA leader. We use a mutant (Haltere-mimic) to show that sequences that normally restrict segmental expression of Ubx in the ectoderm are located downstream from the RNA leader.     

Effect of insulin on anabolic processes and growth in hypothyroid rats at various age periods

Studies have been made on a possibility of compensation of growth retardation in hypothyroid rats by insulin. In 30-day rats, compensation is not complete, although hypothyroidism is less significant as compared to that in animals which received merkazolil together with insulin. Further administration of insulin to rats up to the 90th day, resulted in a significant increase in the growth rate of skeletal muscles, body mass, protein content of skeletal muscles, as well as glycogen content of the liver and skeletal muscles. Thyroid insufficiency may be compensated by insulin alone, i.e. without simultaneous administration of thyroid hormones.     

The effect of frontal cortex lesion on the activity of the dopaminergic system in rat striatum

The experiment was carried out on male Wistar rats weighing 180-220 g with lesion in the cortex of the frontal lobe. The activity of the dopaminergic system was studied by means of behavioural tests such as determination of spontaneous motor activity, apomorphine-induced stereotypy, haloperidol-induced catalepsy. Increased intensity of stereotypy was observed reaching a maximum 14 days after frontal lobe damage. Moreover, a slight tendency was observed for inhibition of haloperidol-induced catalepsy without changes in the spontaneous motor activity of the animals. Biochemical investigations demonstrated reduced dopamine content in the striatum on the side of the lesion.     

Synthesis and properties of DNA duplexes containing hydrocarbon bridges instead of a nucleoside residue

DNA duplexes 14 bp long containing an EcoRII and MvaI restriction site in which a nucleoside is substituted by 1,3-diaminopropane or 1,3-propanediol residue have been chemically synthesized. Diaminopropane bridge was introduced by the chemical ligation, whereas the oligonucleotide containing propanediol was prepared by automatic solid phase phosphoroamidite method on "Victoria-4M" synthesizer. As CD and UV spectra show, the modification destabilises the duplex by 18-20 degrees C without essential distortion of the double helix, except for increase of the conformational mobility in the modified site.     

The nucleolar RNA-binding protein B-36 is highly conserved among plants

The nucleolar protein B-36 is an RNA-associated protein which has a number of properties in common with pre-mRNA-binding proteins (hnRNP proteins). Like the hnRNP proteins, B-36 appears to be evolutionarily conserved among various eukaryotes (protists and several animal species). The conservation of B-36 throughout the plant kingdom has been investigated using a panel of nine monoclonal antibodies previously shown to recognize a minimum of four different epitopes in Physarum B-36, the protein used to generate the monoclonal antibodies. Two of the epitopes (I and III) are widely conserved in 34 kDa proteins (presumably B-36 homologues) from the various species tested (Chlamydomonas, moss, fern, oat, onion, carrot, and bean). Using immunofluorescence localization in moss and carrot protoplasts, the cross-reacting proteins were shown to be restricted to the nucleolus, further confirming their probable homology to B-36. Epitopes I and III are also unique to the B-36 homologues as demonstrated by the failure of any other bands to cross-react. Another epitope (IV) was specifically recognized in the plant B-36 homologues but exhibited greatly reduced affinity for the monoclonal antibody relative to Physarum B-36. The remaining epitope (II), unlike the others, exhibited variable conservation in the plant B-36 homologues and, in addition, was present in several other seemingly unrelated proteins. Finally, several of the plant species exhibited two cross-reacting variants at roughly the 34 kDa position and in at least one of these cases a single monoclonal antibody was able to distinguish between the two variants, a result indicating that the variants do have bona fide structural differences.(ABSTRACT TRUNCATED AT 250 WORDS)     

Differentiation of mitotic melanoma cells from G2 cells and their isolation by use of 5-bromo-2'-deoxyuridine and propidium iodide

This report describes a method by which mitotic cells were isolated from nonsynchronized Cloudman melanoma cells that had been pulse labeled with 5-bromo-2'-deoxyuridine (BrdUrd) and double-stained with a fluoresceinated monoclonal antibody to BrdUrd and with propidium iodide (PI). In initial experiments, melanoma cells were first pulse labeled with BrdUrd, treated with prostaglandin E1 (PGE1 10 micrograms/m1) or vehicle (0.1% ethanol) for up to 24 hours, then stained with anti-BrdUrd and PI. PGE1-treated cells monitored at 3-hour intervals were observed to migrate from S phase to G2 phase, then, enigmatically, back into the late S phase region of the distribution. In other experiments, cells treated with PGE1 were pulse labeled with BrdUrd at the end of the treatment period and harvested. In these experiments, there was a small, discrete subpopulation of cells within the late S phase region of the DNA distribution that was negative for anti-BrdUrd. This subpopulation of cells was sorted and examined by light microscopy. We observed that 95% of these BrdUrd-negative "S phase" cells were mitotic cells. Since mitotic cells and G2 cells have equivalent amounts of DNA, the reduced red fluorescence exhibited by these cells may be due to a greater sensitivity to denaturation, which has been described for DNA of mitotic cells, and would account for the phenomenon of cells appearing to move "backwards" in the cell cycle. This report indicates that although the BrdUrd/PI method can further define the cell cycle into four compartments, it can also lead to over-estimation of S phase cells in kinetic studies because of contaminating mitotic cells.     

Ultrastructural alterations in cardiac and skeletal muscles in experimental diabetes mellitus

In 18 alloxan-diabetic and 12 metabolically healthy dogs cardiac and skeletal muscles have been studied electronmicroscopically. Myopathy-like alterations, as widening of Z band material, alterations of mitochondria as well as of collagen fibers were observed in the diabetic myocardium. In skeletal muscle nemalin bodies were found. These latter alterations don't develop in insulin-treated diabetic state.