Galactokinase: evidence for a new racial polymorphism

Activities of galactokinase and galactose-1-phosphate uridyltransferase in red cells were assayed in a mixed racial population of 645 pregnant women. The distribution of individual transferase activities for black subjects was the same as that for whites. In contrast, the distributions of individual galactokinase activities differed significantly in blacks and whites, the mean for the black population being 30 percent lower than the mean for the white population. The same racial difference was found when red cell galactokinase activity was examined in males and in newborns. Because low-, intermediate-, and high-galactokinase activities appear to segregate within several black families, this observed difference suggests a new, racially determined enzyme polymorphism.     

Phanerozoic-cryptozoic and related transitions: new evidence

The fossil Pteridinium, a distinctive component of a worldwide early metazoan (Ediacaran)assemblage, is provisionally recorded from probable early Cambrian strata in eastern California. In context with other evidence, this finding implies a Cambrian age for the Ediacaran fauna and approximate coincidence of limits between Phanerozoic-Cryptozoic, Paleozoic-Precambrian, and Cambrian-Precambrian.     

Evidence for monophyly and arthropod affinity of cambrian giant predators

The Chinese Early Cambrian Chengjiang fauna includes three different anomalocaridids, a globally spread, extinct marine group including the largest known Cambrian animals. Anomalocaridids were active predators, and their presence implies that a complex ecosystem appeared abruptly in the earliest Phanerozoic. Complete specimens display several sets of characters shared only with some other exclusively Cambrian forms. This evidence indicates that anomalocaridids, Opabinia, and Kerygmachela form a monophyletic clade. Certain features indicate arthropod affinities of the lade, and for this group an unnamed (sub)phylum-level taxon within an arthropod (super)phylum is proposed.     

Phosphoglucomutase: evidence for a new locus expressed in human milk

Electrophoretic study of phosphoglucomutase (PGM) in human milk revealed different patterns that can be explained by the existence of a locus distinct from the common PGM1, PGM2, and PGM3. One hundred and forty samples were tested and the results showed four different alleles of PGM4 whose frequencies were under Hardy-Weinberg equilibrium.     

Spreading of the ocean floor: new evidence

It is suggested that the entire history of the ocean basins, in terms of oceanfloor spreading,is contained frozen in the oceanic crust. Variations in the intensity and polarity of Earth's magnetic field are considered to be recorded in the remanent magnetism of the igneous rocks as they solidified and cooled through the Curie temperature at the crest of an oceanic ridge, and subsequently spread away from it at a steady rate. The hypothesis is supported by the extreme linearity and continuity of oceanic magnetic anomalies and their symmetry about the axes of ridges. If the proposed reversal time scale for the last 4 million years is combined with the model, computed anomaly profiles show remarkably good agreement with those observed, and one can deduce rates of spreading for all active parts of the midoceanic ridge system for which magnetic profilesor surveys are available. The rates obtained are in exact agreement with those needed to account for continental drift. An exceptionally high rate of spreading (approximately 4.5 cm/year) in the South Pacific enables one to deduce by extrapolation considerable details of the reversal time scale back to 11.5 million years ago. Again, this scale can be applied to other parts of the ridge system. Thus one isled to the suggestion that the crest of the East Pacific Rise in the northeast Pacific has been overridden and modified by the westward drift of North America, with the production of the anomalous width and unique features of the American cordillera in the western United States. The oceanicmagnetic anomalies also indicate that there was a change in derection of crustal spreading in this region during Pliocene time from eastwest to southeast-northwest. A profile from the crest to the boundary of the East Pacific Rise, and the difference between axial-zone and flank anomalies over ridges, suggest increase in the frequency of reversal of Earth's magnetic field, together, possibly, with decrease in its intensity, approximately 25 million years ago. Within the framework of ocean-floor spreading, it is suggested that magnetic anomaliesmay indicate the nature of oceanic fracture zones and distinguish the parts of the ridge system that are actively spreading. Thus data derived during the past year lend remarkable support to thehypothesis that magnetic anomalies may reveal the history of the ocean basins.     

Early silurian spore tetrads from new york: earliest new world evidence for vascular plants?

Several taxa of abundant cutinized trilete spores from earliest Silurian shale in New York predate by almost an entire period vascular land plant megafossils. Paleoecological evidence suggests that these spores may represent vascular land or semiaquatic plants but a bryophytic origin cannot be precluded on the basis of spore characters. An algal origin is considered unlikely.     

Bacterial rhodopsin: evidence for a new type of phototrophy in the sea

Extremely halophilic archaea contain retinal-binding integral membrane proteins called bacteriorhodopsins that function as light-driven proton pumps. So far, bacteriorhodopsins capable of generating a chemiosmotic membrane potential in response to light have been demonstrated only in halophilic archaea. We describe here a type of rhodopsin derived from bacteria that was discovered through genomic analyses of naturally occuring marine bacterioplankton. The bacterial rhodopsin was encoded in the genome of an uncultivated gamma-proteobacterium and shared highest amino acid sequence similarity with archaeal rhodopsins. The protein was functionally expressed in Escherichia coli and bound retinal to form an active, light-driven proton pump. The new rhodopsin exhibited a photochemical reaction cycle with intermediates and kinetics characteristic of archaeal proton-pumping rhodopsins. Our results demonstrate that archaeal-like rhodopsins are broadly distributed among different taxa, including members of the domain Bacteria. Our data also indicate that a previously unsuspected mode of bacterially mediated light-driven energy generation may commonly occur in oceanic surface waters worldwide.     

Microcracking and healing in granites: new evidence from cathodoluminescence

Quartz grains in granitic rocks usually have blue cathodoluminescence (CL). Within the blue-luminescing grains, there are often red-luminescing domains which are frequently impossible to detect without CL contrast. This finding suggests that the red-luminescing quartz is sealing preexisting mnicrocracks. The presence of these now-healed microcracks has important implications with respect to the role of pore fluid pressure and fluid transfer in metamorphism, the origih of granites, longperiod crustal deformation, earthquake mechanics, physical properties of rocks, and deep-seated geothermal energy.     

Electrophoresis of flexible macromolecules: evidence for a new mode of transport in gels

Movement of macromolecules through low concentration agarose gels was investigated with linear poly(styrenesulfonate), linear DNA, star-shaped poly(styrenesulfonate), and circular DNA. Mobilities of weakly entangled flexible macromolecules were independent of molecular radius; within a homologous chemical sequence, electrophoretic separation at low field strengths depended solely on the degree of polymerization. These observations cannot be explained either by sieving or by reptation mechanisms; transport was apparently controlled by spatial variations of chain configurational entropy. Only when the chain was highly entangled did chain topology affect mobility. Evidence for entropically regulated transport clarifies how gel electrophoresis separates flexible macromolecules.     

Partial reversion in yeast: genetic evidence for a new type of bifunctional protein

Two kinds of phenotypic expression in purine biosynthesis result from recessive mutation to adel2 in baker's yeast. The mutants are adenine-specific, blocked in the conversion of inosine 5'-phosphate to adenylosuccinic acid; their response to inhibition of pathway activity by adenine is considerably reduced. Allelic partial reversions can restore prototrophy without correcting the regulatory defect imparted by the primary mutation. The separation of the two properties of the locus by allelic mutation supports the hypothesis that the locus specifies a protein of two independent functions, enzymatic and regulatory.     

Land clearance in the irish neolithic: new evidence and interpretation

Time scales are derived, from radiocarbon dating of pollen diagrams, for Neolithic land clearance at three Irish sites. Three stages are distinguished beginning in the 4th millennium B.C.: stage A, clearance and farming (possibly arable), 100 to 400 years; stage B, farming (possibly pastoral), 150 to 200 years; and stage C, forest regeneration, 50 to 100 years.     

Density gradients in a rotating stratified fluid: experimental evidence for a new instability

Velocity gradients induced in a rapidly rotaiting, density-stratified saltwater solution by a slowly rotating disk produce sharp vertical gradients of density, which appear as regularly spaced, curved horizontal sheets when the ratio of angular velocities exceeds a critical value. The existence of the sheets is apparently a finite amplitude manifestationl of a recently proposed viscous instability.     

Precambrian age of the Boston basin: new evidence from microfossils

A Vendian (Late Proterozoic Z) age has been determined for the Boston Basin by comparison of a microflora from the Cambridge Argillite with other late Precambrian assemblages. The microfossils, which include Bavlinella cf. faveolata, are preserved as petrifactions in pyrite. This age designation for the sedimentary rocks of the Boston Basin should allow for the reinterpretation of the structure of the basin and its regional correlations.     

Thyroglobulin: evidence for crystallization and association

Crystals of thyroglobulin have been obtained from ammonium sulfate solutions and have been examined by electron microscopy as shadowed carbon replicas. Unit size in the crystal is 228 +/- 9 angstroms, which corresponds to a molecular weight of 5,300,000. Data are in accord with the possibility that this unit represents a polymer of thyroglobulin.     

Plant chemistry and the evolution of host specificity: new evidence from heliconius and passiflora

Larval growth rates of Heliconius butterflies do not closely parallel host plant choice, an indication that factors other than host plant chemistry are important in evolving host specificity. High growth rate in one species is correlated with reduction in number of palatable host species. This suggests a mechanism by which ecologically restricted species become progressively biochemically specialized.     

Chromosome painting of telomeric repeats reveals new evidence for genome evolution in peanut

Interspecific hybridization is an important approach to improve cultivated peanut varieties. Cytological markers such as tandem repeats will facilitate alien gene introgression in peanut. Telomeric repeats have also been frequently used in chromosome research. Most plant telomeric repeats are(TTTAGGG)n that are mainly distributed at the chromosome ends, although interstitial telomeric repeats(ITRs) are also commonly identified. In this study, the telomeric repeat was chromosomally localized in 10 Arachis species through sequential GISH(genomic in situ hybridization) and FISH(fluorescence in situ hybridization) combined with 4',6-diamidino-2-phenylindole(DAPI) staining. Six ITRs were identified such as in the centromeric region of chromosome Bi5 in Arachis ipa?nsis, pericentromeric regions of chromosomes As5 in A. stenosperma, Bho7 in A. hoehnei and Av5 in A. villosa, nucleolar organizer regions of chromosomes As3 in A. stenosperma and Adi3 in A. diogoi, subtelomeric regions of chromosomes Bho9 in A. hoehnei and Adu7 in A. duranensis, and telomeric region of chromosome Es7 in A. stenophylla. The distributions of the telomeric repeat, 5S r DNA, 45 S r DNA and DAPI staining pattern provided not only ways of distinguishing different chromosomes, but also karyotypes with a higher resolution that could be used in evolutionary genome research. The distribution of telomeric repeats, 5S r DNA and 45 S r DNA sites in this study, along with inversions detected on the long arms of chromosomes Kb10 and Bho10, indicated frequent chromosomal rearrangements during evolution of Arachis species.     

Early evolution of avian flight and perching: new evidence from the lower cretaceous of china

Fossil bird skeletons discovered in Lower Cretaceous lake deposits in China shed new light on the early evolution of avian flight and perching. The 135 million-year-old sparrow-sized skeletons represent a new avian, Sinornis santensis, n. gen. n. sp., that preserves striking primitive features such as a flexible manus with unguals, a footed pubis, and stomach ribs (gastralia). In contrast to Archaeoperyx, however, Sinornis exhibits advanced features such as a broad sternum, wing-folding mechanism, pygostyle, and large fully reversed hallux. Modern avian flight function and perching capability, therefore, must have evolved in small-bodied birds in inland habitats not long after Archaeopteryx.     

Structure of 3' terminal region of type II human T lymphotropic virus: evidence for new coding region

The sequence of the 3' terminus of the human T lymphotropic virus type II (HTLV-II) was determined and compared to the corresponding sequence of HTLV-I. The 1557-nucleotide-long sequence can be divided into a 5' region that is not conserved between the two viruses, and a 3', 1011-nucleotide-long region that is highly conserved and that corresponds precisely with a long open reading frame for both HTLV-I and -II. The proteins that could be encoded by these open reading frames have a molecular weight of about 38,000 and are closely related in primary amino acid sequence. The genomic structure in the 3' region of HTLV was found to be similar to that of bovine leukemia virus.     

The theropod ancestry of birds: new evidence from the late cretaceous of madagascar

A partial skeleton of a primitive bird, Rahona ostromi, gen. et sp. nov., has been discovered from the Late Cretaceous of Madagascar. This specimen, although exhibiting avian features such as a reversed hallux and ulnar papillae, retains characteristics that indicate a theropod ancestry, including a pubic foot and hyposphene-hypantra vertebral articulations. Rahona has a robust, hyperextendible second digit on the hind foot that terminates in a sicklelike claw, a unique characteristic of the theropod groups Troodontidae and Dromaeosauridae. A phylogenetic analysis places Rahona with Archaeopteryx, making Rahona one of the most primitive birds yet discovered.