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Summary To investigate physiological processes generated by endogenous circadian rhythms on the molecular level, we have identified clock-controlled genes In the long-day plant Sinapis aiba L. A cDNA library was differentially screened using cDNA probes representing transcripts expressed at either the middle of the light period or the middle of the dark period. Two closely related groups of transcripts, Sagrp1 and Sagrp2, controlled by a circadian rhythm have been isolated. RNA blot analysis verified that transcript levels oscillate in plants grown in light/dark cycles with maxima between ‘Zeitgober’ time (zt)8 and zt12 (8–12 h after onset of illumination) and minima around zt20. Steady-state mRNA levels continue to oscillate in plants shifted from light/dark cycles to constant light. No synchronous mRNA oscillations are found in plants grown from seed in constant light at constant temperature, suggesting that the clock has to be entrained initially. In contrast, when plants grown in constant light are exposed to rhythmic temperature shifts oscillations of steady-state Sagrp mRNA levels are induced, indicating that temperature acts as an alternative external stimulus (zeitgeber) other than light to entrain the oscillator. In situ hybridization reveals that both transcript groups are expressed predominantly in meristematic and growing tissue. Strong expression is observed in the leaf primordia of the shoot apex, the procambial strands, cambium and in all cell layers of young leaves around zt12. In contrast, little or no signal is found on tissue sections isolated at zt20. This indicates that the oscillator(s) regulating Sagrp transcript fluctuations operate(s) synchronously in different organs. For both transcript groups cDNAs were isolated corresponding to unspliced pre-mRNAs or to transcripts generated by the use of a second 5′ splice site. The cDNAs corresponding to the fully spliced transcripts contain open reading frames for polypeptides of 16 kDa, each containing a putative N-terminal RNA recognition motif and a C-terminal region rich in glycine. The predicted proteins show strong homology to an ABA-inducible glycine-rich protein from maize embryos and to the mammalian RNA-binding protein A1 of the heterogeneous nuclear ribonucleoprotein complex involved in pre-mRNA splicing. The SaGRP protein fluctuates with a very low amplitude over light/dark cycles. Immunogold labeling demonstrates the presence of the SaGRP protein within the nucleus of the investigated meristematic cells of young leaves.

Background. The Mammography Quality Standards Act (MQSA) became effective October 1, 1994, and requires all mammography facilities to meet quality standards as promulgated by the Food and Drug Administration (FDA). The FDA undertook an assessment of the MQSA federal certification requirements on the availability of mammography facilities. Methods. A survey of states on mammography facility closures between October 1, 1993, and October 1, 1994, was conducted. MapInfo software was used to link zip codes to demographic databases. The characteristics of closed facilities were compared to certified facilities as of December 15, 1994. Results. A total of 369 facilities (3.5%) had closed. This closure rate was comparable to previous years' rates (2.5–10%). As of December 15, 1994, 10,142 certified facilities were operating. Relative to their distribution in the United States, closures in rural areas were proportional, but there were more facility closures in the minority areas and in poverty areas. However, the relative distributions of facilities to these areas' populations were unchanged. Conclusions. Impact on facility availability has been minimal.

hear his informal remarks. I remember his gentle but commanding six-and-a-half-foot figure, and howexercising the sure instincts of an old actorhe sidled into the most brightly lit spot on the stage. Guthrie talked about his work as director at the Old Vic, at Stratford-on-Avon, in London's West End, at the Metropolitan Opera, on Broadway. He enjoyed working in the United States, he said, but he was disenchanted with what he called "Broadway's tawdry commercialism " and hoped to start a new theater in the tradition of the classic British repertory companies. He had already helped establish one great North American acting ensemble: the Shakespeare Festival in Stratford, Ontario. Now he wanted a theater "in the provinces " as he called everything beyond the Hudsonand his visit to the Midwest was part of an exploratory tour. Guthrie's other concern was the hand-to-mouth financial condition of resident theaters in the U.S. He

it a federation, a merger, a consolidation, or an amalgamation. Whatever the nomenclature, two private institutionsone strictly a school of science and engineering, the other known for its strong liberal arts and professional programs pooled their resources in 1967 in what still stands as one of the most important cooperative moves ever made in American higher education: Case Institute of Technology and Western Reserve University, next-door neighbors in Cleveland, became Case Western Reserve University (CWRU). John S. Millis, president of Reserve for 18 years prior to federation, called it "the first non-shotgun marriage of two educational institutions in the history of America." Other mergers have been prompted by the imminent bankruptcy of one or both institutions. This one was motivated, as the board of trustees at Reserve framed it in a 1966 resolution, by a wish "to bring into being a nationally recognized community of academic excellence." That was during the Golden Age of higher education, when colleges could luxuriate in noble aspirations untainted by fiscal considerations. As it later turned out, though, the Case-Reserve federation was a lifesaver when the financial crunch came. "If we hadn't federated, the hard times of the 1970s would have pushed us over the cliff," says Louis A. Toepfer, CWRU's president since 1970. "I don't see how we could have survived individually." Today CWRU is a unitary institution. On the local level, it is a source of unabashed civic pride in a community beset by such indignities as an attempted mayoral recall and a bankrupt public school system. On the national level, it has a reputation both in the sciences and in the humanities even more solid than its components formerly enjoyed. On a practical level, it is the envy of countless private institutions; it is deficit-free (quite miraculously, considering its stormy fiscal history). It appears to have solved most of the problems stemming from federationapprehension on the part of administrators, faculty, and nonacademic staff who woke up one morning to discover that they were duplicate (and perhaps dispensable) personnel; alumni who bristled at change; and, of course, the massive task of combining finances. A few problems still persist. Some of them are frivolous: What can you do about a university whose name is cumbersome when recited in full and whose acronym students insist upon pronouncing "Screw U "? Others are more profound: Why does everyone still seem embarrassed over the forced resignation of CWRU's first president, who was one of the architects of federation? Western Reserve College, forerunner of Western RUTH FISCHER has written for magazines ranging from Playboy to The New Republic, The Nation, Consumer Reports, and Change. Formerly an associate editor of Change, she now is an editor for Atlas World Press Review.

The effect of chemical stress on the polypeptide composition of the intercellular fluid of barley (Hordeum vulgare L.) and tomato (Lycopersicon esculentum Mill.) leaves has been studied. In some dicotyledonous plant species, including tomato, exposure to chemical stress leads to the denovo synthesis of intercellular proteins known as pathogenesis-related proteins which have been implicated to be part of a defence mechanism. In barley, however, no such changes in the polypeptide composition of the intercellular fluid could be detected. On the other hand, similar stress conditions induce in barley a strong accumulation of mRNA encoding leaf-specific thionins. These barley thionins represent a novel class of cell-wall proteins toxic to phytopathogenic fungi and are possibly involved in the defence mechanism. These proteins could not be detected in tomato plants. In contrast to the pathogenesis-related proteins of dicotyledonous plants, the leaf-specific thionins of barley are not present in the intercellular fluid of leaves. These results indicate that barley may have evolved a different mechanism to cope with the presence of stress.

As part of an attempt to analyze rhythmic phenomena in the long-day plant Sinapis alba L. at the molecular level, we have searched for mRNAs whose concentration varies as a function of time of day. Differential screening of a cDNA library established from mRNAs expressed at the end of the daily light phase with probes representing transcripts expressed predominantly in the morning or evening has identified one major transcript. The cDNA, Saglp, encodes a predicted 22-kD protein with an N-terminal signal sequence. The protein shows homology to germin, a protein expressed in wheat embryos after onset of germination. The Saglp mRNA level undergoes circadian oscillations in light/dark cycles with maxima between 8 and 12 PM (zeitgeber time [zt] 12-zt16) and minima around 8 AM (zt0). In plants grown from seed in constant light, transcript levels are constitutive. In constant light regular temperature shifts function as an alternative “zeitgeber” to initiate Saglp transcript oscillations. At the cellular level, Saglp transcripts are expressed in the epidermis and spongy parenchyma of young leaves, and in distinct regions of the epidermis and the cortex in stems and petioles. Strong signals are observed in these tissues around zt12, whereas little expression is found around zt20, suggesting that the underlying oscillatory mechanism(s) operate(s) synchronously in different plant organs. The SaGLP steady-state protein concentration remains constant over light/dark cycles. Immunogold labeling shows that the SaGLP protein is associated with primary cell walls.