Alkaline phosphatase in cholestatic and cirrhotic rats. A biochemical and histochemical study

Alkaline phosphatase (ALP) was studied by enzyme histochemical methods and by biochemical quantitations in rat livers with chronic bile duct obstruction and experimental cirrhosis. The most evident ALP increase was histochemically found in portal tracts of rats with bile duct obstruction and localized to the walls of proliferating blood vessels. Furthermore, a slight canalicular membrane enzyme increase was histochemically found in both groups, most evident in cirrhosis, whereas the biochemical assay of ALP in serum and liver from both pathological groups showed 3 times higher values compared to controls. The portal tracts did not seem to contribute to the serum increase, since the rise of serum ALP was similar in chronic bile duct obstruction and in experimental cirrhosis without changes of the portal tracts. It is concluded that the increase ALP activity in serum from rats with bile duct obstruction and cirrhosis mainly has a hepatocytic origin.     

Investigation of transport-associated phosphorylation of sugar in yeast mutants (snf3) lacking high-affinity glucose transport and in a mutant (fdp1) showing deficient regulation of initial sugar metabolism

Pool-labeling experiments with 2-deoxyglucose in derepressed cells of the yeastSaccharomyces cerevisiae confirmed the previously reported results pointing to the possible existence of transport-associated phosphorylation of sugar. In yeast mutants containing a disruption or an inactivating point mutation in thesnf3 gene, which codes for the high-affinity glucose carrier, no evidence for transport-associated phosphorylation of 2-deoxyglucose was observed. If transport-associated phosphorylation in yeast exists, it is apparently not mediated by the low-affinity glucose carrier. Mediation by the high-affinity carrier would fit with the known requirement of an active kinase for high-affinity sugar transport. A mixed type of uptake in cells having both carriers would explain many of the problems associated with the 2-deoxyglucose pool-labeling experiments. Since mutants that have only low-affinity glucose transport are not deficient in the glucose-induced RAS-mediated cAMP signal, transport-associated phosphorylation of glucose is not required for or involved in the induction of the signal. The yeastfdp mutant, which dies on media containing fermentable sugars because of overaccumulation of sugar phosphates, also did not show any evidence for the existence of transport-associated phosphorylation. The same was true for the double mutantfdp snf3. The latter also showed the typicalfdp phenotype, indicative that the lethality on media containing fermentable sugar is owing to aberrant regulation of low-affinity transport. The high protein kinase activity in thefdp mutant does not appear to be responsible for the absence of evidence for transport-associated phosphorylation, because another mutant with high protein kinase activity, thebcy mutant, displayed normal transport behavior.     

The Upper Cave at Zhoukoudian and the origins of the Mongoloids

The best evidence for identifying the inhabitants of northeast Asia in the terminal Pleistocene or early Holocene periods is provided by the human burials from the Upper Cave at Zhoukoudian, and in particular the “Old Man”. Apart from the Minatogawa finds on Okinawa, all Late Pleistocene human remains from East Asia that are reasonably well published are poorly preserved and often have equivocal dates. Since the time the Upper Cave was excavated it has been supposed that the human remains were the link between “Peking Man” and the modern Mongoloid complex. We have carried out multivariate analyses of the “Old Man” cranium employing new measurements of Weidenreich's cast of the skull and comparative data from Howells' survey of modern human groups. Despite our expectations the analyses have not shown the “Old Man” to be closely linked with the Mongoloids. Considering all the evidence available we conclude that the common belief of a close biological relationship between the people buried in the Upper Cave and the modern Mongoloids is not yet adequately demonstrated. Of crucial importance in interpreting the Upper Cave burials is their antiquity, which is still commonly thought to be in the order of at least 18 000 years. We believe that recent C-14 dates of about 11 000 years, determined from animal bones, indicate the earliest possible date for the burials. The time span between the Upper Cave burials and the earliest known modern Mongoloids in north China is in the order of about 4–5000 years. It is possible that a major population shift has occurred in north China between the terminal Pleistocene and the mid Holocene, when farming first appears. If this is so, the Upper Cave people may not have been closely allied to the Mongoloid groups that now inhabit East Asia and the Americas.     

The γ-crystallin gene families: Sequence and evolutionary patterns

Summary The -crystallin proteins consist of two topologically equivalent domains, each built up out of two similar motifs. They are encoded by a gene family, which already contained five members before the divergence of rodents and primates. A further gene duplication took place in each lineage. To analyze the pattern of evolution within this gene family, the coding sequences of six human genes, six rat genes, and four mouse genes were compared. Between species, a uniform rate of evolution of all regions of the protein is seen. The ratio of synonymous to nonsynonymous substitution in the human/rat or human/mouse comparison is much lower than the ratio when rat and mouse are compared indicating that the -crystallin proteins are better conserved in the rodent lineage. Within species, the regions encoding the two external motifs I and III of the protein show a greater extent of nonsynonymous substitution than the regions encoding the two internal protein motifs II and IV. The low extent of synonymous substitution between the second exons (encoding motifs I and II) of the rat -crystallin genes suggests the frequent occurrence of gene conversion. In contrast, a high extent of synonymous substitution is found in exon 3 (encoding motifs III and IV) of the rat genes. The same phenomenon is seen within the human gene family. The frequencies of occurrence of the various dinucleotides deviate less from those predicted from the frequencies of occurrence of each individual nucleotide in the second exons than in the third exons. The sequences of the third exons are significantly depleted in CpG, ApA, and GpT and enriched in CpT and GpA.     

Secondary production of an intertidal mussel (Mytilus edulis L.) population in the Eastern Scheldt (S.W. Netherlands)

We monitored an intertidal mussel (Mytilus edulis L.) population between June 1981 and June 1982 in the Eastern Scheldt estuary (S.W. Netherlands). Density and biomass of the population remained relatively constant over the study period. The shell length growth was described by a Gompertz growth curve. The parameters of this equation were estimated from a log-log-modified Ford-Walford plot of the growth-ring data. The slope of the relationship between animal weight and shell length is season-dependent, mainly due to the spawning cycle in larger mussels.Secondary production is estimated with the growth rate method. In the calculated growth rates the change in slope of the length-weight relationship is incorporated, as well as differences in length growth rates between summer and winter. Secondary production amounts to 156 g AFDW m^–2a ^–1 (expressed per m² of mussel bank). P:B is 0.50 a^–1. The mussel productivity is probably a limiting factor for the density of overwintering Oystercatchers (Haematopus ostralegus).     

Effect of glycerol on plasmid transfer in genetically competent Haemophilus influenzae

Summary The small plasmid pAT4 transformed at characteristically low frequencies those competent Haemophilus influenzae Rd strains that had no DNA homology with this plasmid. Transformation was increased up to 100 times, however, when the recipient cells were exposed to 30% glycerol before plating for transformants. Expression of plasmid resistance markers was then immediate. Ultraviolet irradiation experiments indicated that this large increase was due to release by the glycerol of double-stranded plasmid molecules, presumably from transformasomes. Several other plasmids exhibited the same phenomenon. Dimethylsulfoxide also stimulated plasmid transformation but lysolecithin and high concentrations of NaCl or glucose were ineffective. Glycerol did not increase the efficiency of transformation by either chromosomal DNA or linearized plasmid DNA.     

A new dimension to observations in minirhizotrons: A stereoscopic view on root photographs

Summary With a stereoscope, as used for the inspection of aerial photographs, sequential photographs of roots obtained by the endoscope method from minirhizotrons can yield much more information than hitherto. A series of photographs shows that most of the roots seen in a minirhizotron in grassland grew on the surface of the lexan tube, while there was a gap between the roots and the soil. Decay of the extensive root hair zones around the roots may make new root growth in the gap between rhizotron wall and soil invisible. Some consequences of these observations for the endoscope method are discussed.     

The Cladocera and Copepoda of the Alta water-course, Northern Norway

Cladocera and Copepoda fauna, from ten lakes in the Alta water-course,northern Norway, have been collected and investigated. A totalof 42 species (34 Cladocera and 8 Copepoda) were recorded. Thenumber of Cladoceran species is high when compared with thatregistered for other areas of similar latitude, and Cladoceranspecies abundance is also greater than that reported for otherregions of northern and central Scandinavia. In addition, themean number of planktonic species present at any given timein the lakes (4.9 Cladocera and 3.4 Copepoda) was comparativelyhigh. Eight species have never been recorded as existing farthernorth than the Alta water-course, Three other species have beenrecorded at higher latitudes in North America, but not in Eurasia.Several species, of which there are only a few published records,arc rare in northern Scandinavia, and nine species were notconsidered by Illies (1978), as existing in the region of thepresent study.