A Mutant \u3cem\u3edec-1\u3c/em\u3e Transgene Induces Dominant Female Sterility in \u3cem\u3eDrosophila melanogaster\u3c/em\u3e

The Drosophila dec-1 gene produces three proproteins required for female fertility and eggshell assembly. The three proproteins are distinguished by their C termini. Fc106, the most abundant proprotein, is cleaved within the vitelline membrane to three mature derivatives in a developmentally regulated manner. To define sequences within fc106 that are critical for its function, we created wild-type and mutant versions of an fc106 cDNA transgene. The functional consequences of the mutations were assessed in dec-14, a female-sterile splicing mutant that does not produce the fc106 isoform. The fertility of dec-14 females was restored by the introduction of either a wild-type transgene or a transgene bearing a C-terminal deletion that included fc106-specific sequences. Surprisingly, the removal of internal coding sequences created an aberrant DEC-1 proprotein that induced female sterility when introduced into wild-type flies. Dominant female sterility was not associated with larger deletions that included the fc106 N terminus, suggesting that abnormal juxtaposition of N- and C-terminal sequences in the aberrant proprotein interfered with endogenous DEC-1 proteins. Changes in the fractionation behavior of the endogenous fc106 C-terminal derivative, s60, and morphological changes in the endochorion in response to expression of the aberrant proprotein support this interpretation

fc177, a Minor dec-1 Proprotein, Is Necessary to Prevent Ectopic Aggregation of the Endochorion During Eggshell Assembly in Drosophila

The Drosophila eggshell is a highly specialized extracellular matrix that forms between the oocyte and the surrounding epithelial follicle cells during late oogenesis. The dec-1 gene, which is required for proper eggshell assembly, produces three proproteins that are cleaved within the vitelline membrane layer to multiple derivatives. The different spatial distributions of the cleaved derivatives suggest that they play distinct roles in eggshell assembly. Using extant dec-1 mutations in conjunction with genetically engineered dec-1 transgenes, we show that, although all three dec-1 proproteins, fc106, fc125, and fc177, are required for female fertility, gross morphological abnormalities in the eggshell are observed only in the absence of fc177. The coalescence of the roof, pillar, and floor substructures of the tripartite endochorion suggested that quantitatively minor fc177 derivatives are necessary to prevent ectopic aggregation of endochorion proteins during the assembly process. Expression of a fc177 cDNA in dec-1 null mutants was sufficient to restore spaces within the endochorion layer. Fc177 may function as a scaffolding protein akin to those utilized in viral morphogenesis

\u3cem\u3eDrosophila\u3c/em\u3e Vitelline Membrane Assembly: A Critical Role for an Evolutionarily Conserved Cysteine in the “VM domain” of sV23

The vitelline membrane (VM), the oocyte proximal layer of the Drosophila eggshell, contains four major proteins (VMPs) that possess a highly conserved “VM domain” which includes three precisely spaced, evolutionarily conserved, cysteines (CX7CX8C). Focusing on sV23, this study showed that the three cysteines are not functionally equivalent. While substitution mutations at the first (C123S) or third (C140S) cysteines were tolerated, females with a substitution at the second position (C131S) were sterile. Fractionation studies showed that sV23 incorporates into a large disulfide linked network well after its secretion ceases, suggesting that post-depositional mechanisms are in place to restrict disulfide bond formation until late oogenesis, when the oocyte no longer experiences large volume increases. Affinity chromatography utilizing histidine tagged sV23 alleles revealed small sV23 disulfide linked complexes during the early stages of eggshell formation that included other VMPs, namely sV17 and Vml. The early presence but late loss of these associations in an sV23 double cysteine mutant suggests that reorganization of disulfide bonds may underlie the regulated growth of disulfide linked networks in the vitelline membrane. Found within the context of a putative thioredoxin active site (CXXS) C131, the critical cysteine in sV23, may play an important enzymatic role in isomerizing intermolecular disulfide bonds during eggshell assembly

The Functions of the Multiproduct and Rapidly Evolving \u3cem\u3edec-1\u3c/em\u3e Eggshell Gene Are Conserved Between Evolutionarily Distant Species of Drosophila

The Drosophila dec-1 gene encodes multiple proteins that are required for female fertility and proper eggshell morphogenesis. Genetic and immunolocalization data suggest that the different DEC-1 proteins are functionally distinct. To identify regions within the proteins with potential biological significance, we cloned and sequenced the D. yakuba and D. virilis dec-1 homologs. Interspecies comparisons of the predicted translation products revealed rapidly evolving sequences punctuated by blocks of conserved amino acids. Despite extensive amino acid variability, the proteins produced by the different dec-1 homologs were functionally interchangeable. The introduction of transgenes containing either the D. yakuba or the D. virilis dec-1 open reading frames into a D. melanogaster DEC-1 protein null mutant was sufficient to restore female fertility and wild-type eggshell morphology. Normal expression and extracellular processing of the DEC-1 proteins was correlated with the phenotypic rescue. The nature of the conserved features highlighted by the evolutionary comparison and the molecular resemblance of some of these features to those found in other extracellular proteins suggests functional correlates for some of the multiple DEC-1 derivatives

Chloride waters of Great Britain revisited: from subsea formation waters to onshore geothermal fluids

It has long been known that chloride-dominated saline ground waters occur at depth in the UK, not only beneath the sea but also onshore at depths of a few hundred metres. In a few places in northern England, these saline waters discharge naturally at surface in the form of springs. In recent years, however, these saline ground waters have come to be regarded as resources: as potential geothermal fluids intercepted in deep boreholes. Comparisons of the major ions and stable isotopes (δ2H, δ18O and δ34S) of these saline ground waters with North Sea oilfield formation waters, and with brines encountered in former subsea workings of coastal collieries, reveal that they are quite distinct from those found in North Sea oilfields, in that their as δ2H/δ18O signatures are distinctly “meteoric”. δ34S data preclude a significant input from evaporite dissolution – another contrast with many North Sea brines and some colliery waters. Yet, enigmatically, their total dissolved solids contents are far higher than typical meteoric waters. It is tentatively suggested that these paradoxical hydrogeochemical properties might be explained by recharge during Cenozoic uplift episodes, with high concentrations of solutes being derived by a combination of high-temperature rock–water interaction in the radiothermal granites and/or ‘freeze out’ from overlying permafrost that surely formed in this region during cold periods. Geothermometric calculations suggest these saline waters may well be representative of potentially valuable geothermal reservoirs

The N-terminal Prodomain of sV23 is Essential for the Assembly of a Functional Vitelline Membrane Network in \u3cem\u3eDrosophila\u3c/em\u3e

The vitelline membrane is a specialized extracellular matrix that surrounds and protects the oocyte. Recent studies indicate that it also serves as a storage site for embryonic pattern determinants. sV23, a major vitelline membrane protein, is essential for the morphogenesis of the vitelline membrane as sV23 protein null mutants lay flaccid, infertile eggs. By analyzing a series of sV23 mutant transgenes in the sV23 protein null genetic background, we have shown that sV23 is secreted as a proprotein in functional excess and that C- and N-terminal prodomains are removed successively, following its deposition in the extracellular space. Although a target site for subtilisin-like convertases is essential for N-terminal processing, N-terminal processing is not necessary for the assembly of a functional vitelline membrane layer. While C-terminal truncations were tolerated, the removal of N-terminal sequences lead to the production of flaccid, infertile eggs with a soluble, rather than insoluble, vitelline membrane network. We propose that the hydrophobic N-terminal prodomain plays an early and essential role in aligning molecules within the vitelline membrane network, much like hydrophobic domains within elastin drive the assembly and alignment of molecules within elastin-based extracellular matrices

Age, Race, Life Conditions, Use of Social Welfare Services and the Morale of the Elderly

Although concerned professionals such as Kutner (1956), Cumming (1961), and Lawton (1972), have made strong beginnings in researching the psychological functioning of the elderly, only a few have explored the social and medical conditions of the aged, and especially their use of social welfare services, as these relate to a sense of well-being. Streib (1956) and Maddox (1968) were among the first to relate life-long patterning of social activity to later social activity and life satisfaction. Carp (1966), in a controlled study of housing, reported that housing did not affect the morale of low and middle income elderly. Lawton and Cohen (1974) looked at the reactions of an aged sample to new housing and found that there was only a modest effect on well-being. Adams (1971), in a literature review of correlates of life satisfaction among the elderly, highlighted the regularity with which health as a conditioning variable relates to overall leisure activities. Wolk and Telleen (1976) examined the social and psychological constraints of residence as these affect morale. Cutler (1976) reported that belonging to church-affiliated groups strengthened psychological well-being. Caslin and Calvert (1975) indicated that ethnicity (including race) has an important affect on use of services. Medley (1976) found that the degree of satisfaction with family was indicative of morale. Nevertheless, there is a dearth of studies based upon face-to-face interview derived self-reports from the aged about the social-environmental conditions of their lives and particularly about their utilization of the social services as these relate to morale. The writers believe that such studies can assist helping professions in assessing present social resourcevtse and may offer a sound base for planning social welfare service programs

The Domain of Social Work: What is It

Cast within a framework derived from general systems theory, the authors examine the domain of the social work profession. Domain is first defined as having several components. These are specified and fully expanded as Claimed Domain, Domain Competition, Emerging Domain and Unclaimed Domain. This elaboration is followed by a discussion of some of the constraints that impinge upon the profession\u27s ability to define and to choose its domain

In Heavenly Love Abiding

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