Adipose Tissue-Derived Stem Cells Reduce Acute and Chronic Kidney Damage in Mice

Acute and chronic kidney injuries (AKI and CKI) constitute syndromes responsible for a large part of renal failures, and are today still associated with high mortality rates. Given the lack of more effective therapies, there has been intense focus on the use stem cells for organ protective and regenerative effects. Mesenchymal stem cells (MSCs) have shown great potential in the treatment of various diseases of immune character, although there is still debate on its mechanism of action. Thus, for a greater understanding of the role of MSCs, we evaluated the effect of adipose tissue-derived stem cells (AdSCs) in an experimental model of nephrotoxicity induced by folic acid (FA) in FVB mice. AdSC-treated animals displayed kidney functional improvement 24h after therapy, represented by reduced serum urea after FA. These data correlated with cell cycle regulation and immune response modulation via reduced chemokine expression and reduced neutrophil infiltrate. Long-term analyses, 4 weeks after FA, indicated that AdSC treatment reduced kidney fibrosis and chronic inflammation. These were demonstrated by reduced interstitial collagen deposition and tissue chemokine and cytokine expression. Thus, we concluded that AdSC treatment played a protective role in the framework of nephrotoxic injury via modulation of inflammation and cell cycle regulation, resulting in reduced kidney damage and functional improvement, inhibiting organ fibrosis and providing long-term immune regulation.     

Recessive Lethal Mutations and the Maintenance of Duplication-Bearing Strains of Dictyostelium discoideum

Recessive lethal mutations have been isolated and used to maintain n + 1 aneuploid strains of Dictyostelium discoideum carrying a duplication of part or all of linkage group VII. The recessive lethal mutations, relA351 and relB352, arose spontaneously in diploids; no mutagenic treatment was used in the isolation of these mutations. The probable gene order on linkage group VII is: centromere, relB couA, bsgB, cobA, relA. Maintenance of aneuploids disomic for linkage group VII was made possible by complementation of a rel mutation on each linkage group VII homologue by the corresponding wild-type allele on the other linkage group VII homologue. The duplication-bearing disomic strains were slow-growing and produced faster-growing sectors on the colony edge. Haploid sectors probably arise by a combination of mitotic recombination and subsequent loss of one homologue, diploid sectors may be formed by chromosome doubling to 2n + 2, followed by chromosome loss to return to 2n, and aneuploid sectors may arise by deletion or new mutation.     

On the carrying behaviour of basic South American primates

InCallithrix, Saguinus, Aotus, andCallicebus other group members than the mother participate in infant care. Differences among these species are obvious in respect to the time of being off any caregiver, and in respect to the carrying position (Aotus andCallicebus). Alloparental care, a basic behaviour pattern in these species, has evolved from the parking behaviour of the prosimians. The infants are «parked» at other group members.     

Linkage analysis of the myosin heavy chain gene in Dictyostelium discoideum using a mutation generated by homologous recombination

Summary A mutation (mhcA1 in strain HMM) created by insertional gene inactivation was used to map the Dictyostelium discoideum myosin heavy chain gene (mhcA) to linkage group IV. Three phenotypic traits associated with this mutation (slow colony growth, inability of the mutant to develop past aggregation, and the presence of five to ten integrated vector copies) cosegregated as expected for the consequences of a single insertional event. This linkage was confirmed using a restriction fragment length polymorphism. The mhcA1 mutation was recessive to wild type and was nonallelic with mutations at the following loci on linkage group IV: aggJ, aggL, couH, minA, phgB and tsgB. This work demonstrates the ability to apply standard techniques developed for D. discoideum parasexual genetic analyses to mutants generated by transformation, which is of particular relevance to analysis of genes for which no classical mutations or restriction fragment length polymorphisms are available.     

Nuclear plasmids in the Dictyostelium slime molds

Cellular slime molds are one of only three types of eukaryotes known to contain circular nuclear plasmids. Unlike the 2-microns circle in Saccharomyces, different strains of Dictyostelium can carry different, nonhomologous plasmids. Covalently closed, circular DNA plasmids have been identified in D. discoideum, D. mucoroides, D. giganteum, and D. purpureum. These plasmids range in size from 1.3-27 kb and in copy number from 50-300 molecules per cell. Plasmids have been identified in approximately one-fifth of all isolates examined. The organization of their DNA in nucleosomes establishes their presence in the nucleus. We have successfully cotransformed endogenous Dictyostelium plasmids into D. discoideum using the G418 resistance shuttle vector B10S. Transformants carrying D. discoideum plasmids are recovered at much higher frequency than those carrying plasmids from the other Dictyostelium species. We have constructed recombinant plasmids based on the D. discoideum plasmid Ddp2 and the G418 resistance gene. With these extrachromosomal vectors, transformed cells are recovered at frequencies of up to 10(-4) per input cell, the vectors are stably maintained at high copy number in the absence of selection, and the vectors can be used to introduce foreign DNA sequences into D. discoideum cells.     

Capture and allocation of nitrogen byQuercus douglasii seedlings in competition with annual and perennial grasses

Summary The spatial overlap of woody plant root systems and that of annual or perennial grasses promotes competition for soil-derived resources. In this study we examined competition for soil nitrogen between blue oak seedlings and either the annual grassBromus mollis or the perennial grassStipa pulchra under controlled outdoor conditions. Short-term nitrogen competition was quantified by injecting¹⁵N at 30 cm depth in a plane horizontal to oak seedling roots and that of their neighbors, and calculating¹⁵N uptake rates, pool sizes and¹⁵N allocation patterns 24 h after labelling. Simultaneously, integrative nitrogen competition was quantified by examining total nitrogen capture, total nitrogen pools and total nitrogen allocation.Stipa neighbors reduced inorganic soil nitrogen content to a greater extent than didBromus plants. Blue oak seedlings responded to lower soil nitrogen content by allocating lower amounts of nitrogen per unit of biomass producing higher root length densities and reducing the nitrogen content of root tissue. In addition, blue oak seedlings growing with the perennial grass exhibited greater rates of¹⁵N uptake, on a root mass basis, compensating for higher soil nitrogen competition inStipa neighborhoods. Our findings suggest that while oak seedlings have lower rates of nitrogen capture than herbaceous neighbors, oak seedlings exhibit significant changes in nitrogen allocation and nitrogen uptake rates which may offset the competitive effect annual or perennial grasses have on soil nitrogen content.     

Selective breeding for variations in patterns of mystacial vibrissae of mice. Bilaterally symmetrical strains derived from ICR stock

The establishment of certain patterns of mystacial vibrissae in mice has been the aim of an extensive breeding program carried on in this laboratory since 1977. In a companion paper we have reported on variations in this pattern in an outbred population of ICR mice. Starting with 21 ICR animals we bred, mostly by brother-sister mating, for 13 bilaterally symmetric patterns of mystacial vibrissae characterized by the presence (or absence) of supernumerary whiskers (SWs). The strains are classified as follows: I, a mouse strain with the standard pattern; II, eight strains bred for the occurrence of SWs at a given site or sites; and III, four mouse strains bred for a maximal number of SWs in different regions of the whiskerpad. Commonly, SWs occur in regions that coincide with the zones of mergence between the three facial processes except for two class II strains in which we bred for SWs in the "straddler" row of vibrissae, and for one class III strain, in which we cultivated the tendency (that appeared late in our program) to have SWs at the crest of a facial process. For classes I and II we analyzed the results for about 18 generations in terms of "improvement," meaning an increase in the percentages of animals with the desired phenotype together with a decreased frequency of undesired SWs. For class III, success in breeding meant the increase of the mean number of the desired SWs. All results led to the same conclusion: there is a genetic basis for the occurrence of SWs. The side preference of a particular SW is not strain dependent. It disappears in those class I and II strains in which almost 100% of animals obtained the desired phenotype. The increase in number of SWs in one zone of mergence does not depend on the presence of SWs in the other. Where tested, we almost always found a representation of an SW in a topologically equivalent location within the "barrelfield" area of the somatosensory cerebral cortex. Except for some diseases early in the breeding program, and some side effects of inbreeding that were eliminated, the population was without obvious defects. Where tested, there was no correlation between the occurrence of SWs and sex. The observed variations in pattern of mystacial vibrissae and their genetic background led us to propose a morphogenetic model for the formation of the pattern of mystacial vibrissae.     

The social structure of primates

A comprehensive comparative study of the social structure of primates revealed: There is no social structure which can be considered typical and discriminative for primates. The varying social structures of the extant primate genera cannot be derived from each other: In contrast it seems that the basic, ancestral condition was that of solitary living animals, loosely aggregated. It can be assumed that the development to a gregarious society took place in two entirely different ways. In terms of primate phylogeny this different development can be shown for the prosimians as well as for the old world and new world monkeys as independently occurring processes. One way of behavioral specialization resulted in close pair bonds or in small family groups, whereas the other led to female groups. The presupposition for the forming of a society based on female groups is the close contact between the individuals and in addition to this, a remarkable social tolerance of females to each other. Social specializations which can be considered transitional from the basic condition are frequently found in prosimians. The kinds of social structures of the particular genera are in close relation to their taxonomic positions in the phylogenetic scala. The number of males in larger social groups of primates is substantially irrelevant as the groups are socially most dependent on the females. The protecting males are socially peripheral. The social units of most of the primate species are matrilocal and endure for several generations. In contrast, the social units of the gibbons and of the pongids are patrilocal and are established anew by the females in each generation. Consequently the social unit disintegrates on the death of the male. In all genera studied, male and female individuals present considerable behavioral differences which can be found even in juveniles. Primates are able to discriminate well known and confident individuals from other less confident; they prefer more confident individuals to less confident ones, and less confident to non-confident. As a consequence of this discriminative ability there is a clear preference for near when compared to distant relatives. The complexity of the social relations is brought about by this ability to discriminate combined with the longevity of primates. This is a characteristic and discriminative feature of the primate order. Dominance relations occur in every social group of primates. Linear hierarchies of dominance have been developed only once in prosimians (Lemur) and also once in simians (Cercopithecinae). Therefore, liner hierarchies are not typical for primates.     

Isolation of a Bacillus stearothermophilus mutant exhibiting increased thermostability in its restriction endonuclease.

A procedure was developed for the selection of spontaneous mutants of Bacillus stearothermophilus NUB31 that are more efficient than the wild type in the restriction of phage at elevated temperatures. Inactivation studies revealed that two mutants contained a more thermostable restriction enzyme and one mutant contained three times more enzyme than the wild type. The restriction endonucleases from the wild type and one of the mutants were purified to apparent homogeneity. The mutant enzyme was more thermostable than the wild-type enzyme. The subunit molecular weight, amino acid composition, N-terminal and C-terminal amino acid residues, tryptic peptide map, and catalytic properties of the two enzymes were determined. The two enzymes have similar catalytic properties, but the molecular size of the mutant enzyme is approximately 6 to 7 kilodaltons larger than that of the wild-type enzyme. The mutant enzyme contains 54 additional amino acid residues, of which 26 to 28 are aspartate/asparagine, 8 to 15 are glutamate/glutamine, and 8 to 9 are tyrosine residues. The two enzymes contained similar amounts of the other amino acids, identical N-terminal residues, and different C-terminal residues. Tryptic peptide analyses revealed a high degree of homology between the two enzymes. The increased thermostability observed in the mutant enzyme appears to have been achieved by a mutation that resulted in the addition of amino acid residues to the wild-type enzyme. A number of mechanisms are discussed that could account for the observed difference between the mutant and wild-type enzymes.     

Inheritance of extrachromosomal ribosomal DNA during the asexual life cycle of Dictyostelium discoideum: examination by use of DNA polymorphisms.

Wild-type isolates of Dictyostelium discoideum exhibited differences in the size of restriction fragments of the extrachromosomal 88-kilobase ribosomal DNA (rDNA) palindrome. Polymorphisms in rDNA also were found among strains derived solely from the NC4 wild-type isolate. These variations involved EcoRI fragments II, III, and V; they included loss of the EcoRI site separating fragments II and V and deletion and insertion of DNA. More than one rDNA form can coexist in the same diploid or haploid cell. However, one or another parental rDNA tended to predominate in diploids constructed, using the parasexual cycle, between haploid NC4-derived strains and haploid wild-type isolates. In some cases, most if not all of the rDNA of such diploids were of one form after ca. 50 generations of growth. Segregant haploids, derived from diploids that possessed predominantly a single rDNA allele, possessed the same allele as the diploid and did not recover the other form. This evidence implies that replication does not proceed from a single chromosomal or extrachromosomal copy of the rDNA during the asexual life cycle of D. discoideum.