Mid-infrared emissivity of partially dehydrated asteroid (162173) Ryugu shows strong signs of aqueous alteration.

The near-Earth asteroid (162173) Ryugu, the target of Hayabusa2 space mission, was observed via both orbiter and the lander instruments. The infrared radiometer on the MASCOT lander (MARA) is the only instrument providing spectrally resolved mid-infrared (MIR) data, which is crucial for establishing a link between the asteroid material and meteorites found on Earth. Earlier studies revealed that the single boulder investigated by the lander belongs to the most common type found on Ryugu. Here we show the spectral variation of Ryugu's emissivity using the complete set of in-situ MIR data and compare it to those of various carbonaceous chondritic meteorites, revealing similarities to the most aqueously altered ones, as well as to asteroid (101955) Bennu. The results show that Ryugu experienced strong aqueous alteration prior to any dehydration.

Promotion of physical activity by Canadian Registered Dietitians in daily practice.

BACKGROUND: Dietitians are in an opportunistic position to promote healthy eating and active living. The purpose of this study was to determine counselling strategies of dietitians 1 year after attending a workshop designed to strengthen dietitians' self-efficacy for promoting physical activity (PA) as an adjunct to regular nutrition practice. METHODS: A convenience sample of Registered Dietitians (RDs) in Alberta, Canada (n=103) responded to an invitation via an electronic newsletter to complete a web-based survey that asked about counselling practices related to PA. RESULTS: Thirty-seven workshop attendees (n=37) were compared with a group of dietitians (n=66) who completed the survey but who did not attend the workshop. Nearly all (91%) respondents reported promoting PA in daily practice. Those who attended the workshop were more likely to refer clients to PA professionals (chi2=12.68, P<0.05) than those who were not workshop attendees. CONCLUSIONS: Despite a relatively modest response rate, there were clear suggestions that RDs in Alberta, Canada promote PA in daily practice and attending a workshop designed to facilitate the use of specific tools and strategies for promoting PA in daily practice resulted in increased referral of their clients to exercise specialists.

The use of time-series data in the assessment of macrobenthic community change after the cessation of sewage-sludge disposal in Liverpool Bay (UK).

Sewage sludge was disposed of in Liverpool Bay for over 100 years. Annual amounts increased from 0.5 million tonnes per annum in 1900 to approximately 2 million tonnes per annum by 1995. Macrofauna and a suite of environmental variables were collected at a station adjacent to, and a reference station distant from, the disposal site over 13 years, spanning a pre- (1990-1998) and post- (1999-2003) cessation period. Univariate and multivariate analyses of the time-series data showed significant community differences between reference and disposal site stations and multivariate analyses revealed station-specific community development post-disposal. Temporal variability of communities collected at the disposal station post-cessation was higher than during years of disposal, when temporally stable dominance patterns of disturbance-tolerant species had established. Alterations of community structure post-disturbance reflected successional changes possibly driven by facilitation. Subtle faunistic changes at the Liverpool Bay disposal site indicate that the near-field effects of the disposal of sewage sludge were small and therefore could be considered environmentally acceptable.

The Drosophila Dpit47 protein is a nuclear Hsp90 co-chaperone that interacts with DNA polymerase alpha.

Hsp90 is gaining increasing importance as a protein involved in controlling the normal functioning of the cell. To do this it apparently interacts with a battery of co-chaperone proteins that are involved in both substrate recognition and the progression of the Hsp90 catalytic pathway. In this report we have identified the Drosophila Dpit47 protein (DNA polymerase interacting tpr containing protein of 47 kDa) through its interaction with the DNA polymerase alpha. This protein is a predominantly nuclear protein, which forms a tight and stoichiometric interaction with Hsp90 and shows interaction with Hsp70. It also has substantial homology to other known Hsp90 co-chaperones, e.g. CNS1 and hop1, making it likely that this protein also functions as an Hsp90 co-chaperone. The interaction with the DNA polymerase alpha is not related to the special situation in early embryos where there are large amounts of maternal protein stockpiles of the polymerase, as it occurs to the same level in early and late embryos and also in proliferating cell culture. However, it does not occur in quiescent cells, making it likely that the protein is related to proliferation. This is also consistent with Dpit47 expression being higher in proliferating cells. The interaction between the Dpit47 and the polymerase takes place predominantly in the nucleoplasm, and seems to involve several subunits of the polymerase in comparable amounts, making it unlikely that it is solely required for the assembly of the polymerase complex. The polymerase can also be seen to interact with Hsp90, and the interaction between Dpit47 and the polymerase is increased by the specific Hsp90 inhibitor geldanamycin. This suggests that a complex of the Dpit47, Hsp90 and DNA polymerase exists in the cell. The interaction between DNA polymerase alpha and Dpit47 completely inhibits the activity of the polymerase. These results suggest that Hsp90 acts as a chaperone for DNA polymerase alpha and that this interaction is mediated through the novel co-chaperone Dpit47. This provides the first suggestion of a role for chaperones in DNA replication in higher eukaryotes.

Identification and characterisation of the Drosophila homologue of the yeast Uba2 gene.

We have identified the Drosophila uba2 protein (dUba2). Analysis of the amino acid composition reveals similarity with both the mammalian (47% identity) and yeast (31% identity) homologues. dUba2 is present throughout the Drosophila life cycle but is most abundant during stages of proliferation. The protein is nucleoplasmic throughout much of the cell cycle, however it is lost from the nucleus during mitosis. The DUba2 localisation in the nucleoplasm is not uniform but is observed as concentrated patches reminiscent of the staining patterns seen for other proteins from this group. The nature of these sites is not clear, however the failure of dUba2 to localise to the sites of chorion amplification in ovaries suggests that they are not sites of ongoing DNA replication.

Importin-alpha3 is required at multiple stages of Drosophila development and has a role in the completion of oogenesis.

The Drosophila importin-alpha3 gene was isolated through its interaction with the large subunit of the DNA polymerase alpha in a two-hybrid screen. The predicted protein sequence of Importin-alpha3 is 65-66% identical to those of the human and mouse importin-alpha3 and alpha4 and 42.7% identical to that of Importin-alpha2 (Oho31/Pendulin), the previously reported Drosophila homologue. Both Importin-alpha3 and Importin-alpha2 interact with similar subsets of proteins in vitro, one of which is Ketel, the importin-beta homologue of Drosophila. importin-alpha3 is an essential gene, whose encoded protein is expressed throughout development. During early embryogenesis, Importin-alpha3 accumulates at the nuclear membrane of cleavage nuclei, whereas after blastoderm formation it is characteristically found within the interphase nuclei. Nuclear localisation is seen in several tissues throughout subsequent development. During oogenesis its concentration within the nurse cell nuclei increases during stages 7-10, concomitant with a decline in levels in the oocyte nucleus. Mutation of importin-alpha3 results in lethality throughout pupal development. Surviving females are sterile and show arrest of oogenesis at stages 7-10. Thus, Importin-alpha3-mediated nuclear transport is essential for completion of oogenesis and becomes limiting during pupal development. Since they have different expression patterns and subcellular localisation profiles, we suggest that the two importin-alpha homologues are not redundant in the context of normal Drosophila development.

Observations of glistening in the environment and its relationship to stereovision.

The relationship between glistening and stereovision is explored. Glistening is defined as the existence of points of light in the field of view of the observer that are observed substantially in only one eye. We define each glistening point to be essentially a point of stereonoise. A theory of the probability of glistening is developed and shows that a threshold point for 100% glistening should exist. The results of field experiments are presented.

Developmental toxicity evaluation of sodium fluoride administered to rats and rabbits in drinking water.

Sodium fluoride (NaF; Cas No. 7681-49-4) is used in fluoridating municipal water supplies, resulting in chronic exposure of millions of people worldwide. Because of a lack of pertinent developmental toxicity studies in the literature, sodium fluoride was administered ad libitum in deionized/filtered drinking water (to mimic human exposure) to Sprague-Dawley-derived rats (26/group) on Gestation Days (GD) 6 through 15 at levels of 0, 50, 150, or 300 ppm and New Zealand White rabbits (26/group) on GD 6 through 19 at levels of 0, 100, 200, or 400 ppm. Higher concentrations via drinking water were not practicable due to the poor palatability of sodium fluoride. Drinking water (vehicle) contained less than 0.6 ppm sodium fluoride (limit of detection) and sodium fluoride content of the feed was 12.4 ppm fluoride (rats) and 15.6 ppm fluoride (rabbits). Maternal food, water, body weights, and clinical signs were recorded at regular intervals throughout these studies. Animals were killed on GD 20 (rats) or 30 (rabbits) and examined for implant status, fetal weight, sex, and morphological development. In the high-dose group of both studies there was an initial decreased maternal body weight gain which recovered over time and a decreased water consumption--attributed to decreased palatability. No clear clinical signs of toxicity were observed. Maternal exposure to sodium fluoride during organogenesis did not significantly affect the frequency of postimplantation loss, mean fetal body weight/litter, or external, visceral or skeletal malformations in either the rat or the rabbit. The NOAEL for maternal toxicity was 150 ppm sodium fluoride in drinking water (approximately 18 mg/kg/day) for rats, and 200 ppm (approximately 18/mg/kg/day rabbits. The NOAEL for developmental toxicity was > or = 300 ppm sodium fluoride (approximately 27 mg/kg/day) for rats and > or = 400 ppm (approximately 29 mg/kg/day) for rabbits administered during organogenesis in drinking water. The total exposure to fluoride (mg F/kg body weight/day from food and drinking water combined) in the mid- and high-dose groups for both species was > 100-fold higher than the range at 0.014-0.08 mg F/kg/day estimated for a 70-kg person from food and fluoridated (1 ppm) drinking water.

Developmental toxicity of sarin in rats and rabbits.

Sarin (Agent GB, isopropyl methylphosphonofluoridate) is an organophosphate cholinesterase inhibitor. Sarin (Type I or Type II) was administered by gavage to CD rats on d 6-15 of gestation at dose levels of 0, 100, 240, or 380 micrograms/kg/d and to New Zealand White (NZW) rabbits on d 6-19 of gestation at dose levels of 0, 5, 10, or 15 micrograms/kg/d. Females were weighed on gestational days (GD) 0, 6-16 for rats and 6-20 for rabbits, and immediately prior to termination (GD 20 for rats and GD 29 for rabbits). All animals were monitored daily for clinical signs of toxicity throughout dosing and until sacrifice. At necropsy, gravid uteri were weighed and examined for the number and status of implants (live, resorbed, or dead). Individual fetal body weight, malformations, and variations (external, visceral, and skeletal) were recorded. Rat and rabbit dams in the high-dose groups exhibited significant signs of maternal toxicity and increased maternal mortality. Examination of gravid uteri revealed no statistical differences among treatment groups in the incidence of resorptions or of dead or malformed fetuses, or in average body weight of live fetuses per litter. These results show no evidence or developmental toxicity in the CD rat or NZW rabbit following exposure to either Type I or Type II sarin during embryonic differentiation and major organogenesis, even at a dose that produced maternal toxicity.

Behavioral teratology and dominant lethal evaluation of nitrous oxide exposure in rats.

Epidemiological studies have suggested that spontaneous abortion may be increased in medical personnel following the sort of chronic low-level exposure to the anesthetic gas nitrous oxide (N2O) seen in surgical or dental operatories. These results are supported by some, but not all, animal studies, and results are less well established at low exposure levels. Behavioral effects in exposed animal offspring have also been observed, but again not in all studies. To further examine this problem, we conducted the present experiments. Adult male or female rats were exposed to trace concentrations of N2O (0%, 0.1%, 0.5%, or 1.0% in air) for 6 h daily either throughout gestation (females) or for 9 weeks (males). Offspring from treated adults were subjected to an extensive behavioral test battery. There were no clear dose-response effects on any of eight behavioural tests for any offspring. Maternal and offspring weights were normal from conception through adulthood. Additionally, we studied effects of N2O on male fertility by mating treated males with untreated females and examining uterine contents. There was no evidence for a substantial decline in fertility of exposed males, although there was a small dose-related trend for resorptions to increase and live births to decrease with increasing paternal N2O exposure. There results suggest that there is little alteration in male or female fertility following chronic exposure to low levels of N2O. There are also no significant long-term behavioral alterations in offspring exposed gestationally to trace levels of N2O via dam or sire.

Isolation and characterization of an RNA-dependent RNA polymerase from Nicotiana clevelandii plants infected with red clover necrotic mosaic dianthovirus.

A template-bound RNA polymerase was isolated from Nicotiana clevelandii plants infected with red clover necrotic mosaic dianthovirus (RCNMV) by differential centrifugation, solubilization with dodecyl beta-D-maltopyranoside, and chromatography on columns of Sephacryl S-400 and Q-Sepharose. Analysis of the purified polymerase by SDS-polyacrylamide gel electrophoresis, followed by silver staining or immunoblotting, showed that it contained virus-encoded proteins of molecular masses 27 kDa and 88 kDa together with several minor proteins possibly of host origin. After removal of endogenous RNA with micrococcal nuclease, the polymerase became template-dependent. It was also template-specific, being able to utilize as templates RNA of two strains of RCNMV, but not RNAs of three viruses in different taxonomic groups, namely cucumber mosaic cucumovirus, tomato bushy stunt tombusvirus and tomato mosaic tobamovirus. The products of RNA polymerase reactions were double-stranded RNAs corresponding to RCNMV RNAs 1 and 2. The ability of the template-dependent RNA polymerase to synthesize RNA was completely inhibited by antibodies to a peptide containing the GDD motif, whereas the activity of the template-bound enzyme was unaffected by these antibodies.

Developmental neurotoxicity evaluation of orally administered isopropanol in rats.

Isopropanol was administered by gavage to timed-mated rats from Gestation Day (GD) 6 through Postnatal Day (PND) 21. Doses administered were 0, 200, 700, or 1200 mg/kg/day in a volume of 5 ml/kg. The dams were allowed to deliver and body weights and food consumption were recorded during gestation and lactation. Pups were counted, examined, sexed, and weighed on PND 0, 4, 7, 13, 17, 21, 36, 49, and 68. Litters were culled to eight pups (4:4 or 5:3 sex ratio) on PND 4 and litters without acceptable numbers of male and female pups were eliminated from the study. Pups were weaned on PND 22, and two pups from each litter and their dams were killed. Six of these pups from each dose group were perfused in situ for histopathological examination of the central and peripheral nervous system. Brains of the remaining pups were divided into four regions and weighed. Maternal liver and kidney weights were recorded. Weaned pups were assessed for day of testes descent or vaginal opening and for motor activity on PNDs 13, 17, 21, 47, and 58; auditory startle on PNDs 22 and 60; and active avoidance on PNDs 60-64. These pups were euthanized and examined on PND 68. One high-dose dam died on PND 15, but there were no other clinical observations or effects on maternal weight, food consumption, or gestation length. Pup survival, weight, sex ratio, and sexual maturation were unaffected. There were no biologically significant findings in the behavioral tests, no changes in organ weights, and no pathological findings that could be attributed to isopropanol exposure. In conclusion, there was no evidence of developmental neurotoxicity associated with isopropanol exposure as high as 1200 mg/kg/day.

Use of the radiolabeled murine monoclonal antibody, 111In-CYT-103, in the management of colon cancer.

Monoclonal antibodies directed at tumor-associated antigens may be useful adjuncts for the management of patients with colorectal cancer. The murine monoclonal antibody, B72.3, binds Tag-72, a cell-surface antigen, which is expressed by colorectal carcinoma cells. We investigated the benefit of indium-111-labeled B72.3, 111In-CYT-103, in localizing the presence and extent of disease in patients with suspected or biopsy-proven primary colorectal cancer and in patients with apparently localized recurrent colorectal adenocarcinoma. Twenty patients were enrolled in this study. Each patient received 1 mg of B72.3 labeled with 4 to 5 mCi of 111In. Patients then underwent planar and single-photon emission computed tomographic imaging 2 to 5 days after infusion. Fifteen patients underwent surgery 1 to 14 days after scanning. There were 11 true positives, 1 false positive, 2 true negatives, and 1 false negative. The 111In-CYT-103 scan correctly identified the presence or absence of tumor in the 15 patients in whom biopsies were obtained, for an accuracy rate of 87%. Overall, 111In-CYT-103 supplied clinically useful information regarding the extent of disease that was not previously reported by standard techniques in 33% (5 of 15) of patients who underwent surgical exploration. We conclude that 111In-CYT-103 is a promising imaging agent for patients with potentially resectable recurrences and for those patients with a presumed isolated primary tumor requiring preoperative staging.

Effects of reproductive tract glutathione enhancement and depletion on ethyl methanesulfonate-induced dominant lethal mutations in Sprague-Dawley rats.

The effects of altering glutathione (GSH) levels in the male reproductive tract have been studied in an attempt to establish a link between chemical-induced perturbations in glutathione and susceptibility of spermatozoa to chemical insult. Tissue GSH levels were enhanced by a treatment regimen of N-acetylcysteine (NAC) (250 mg/kg, 4 treatments at 2 h intervals). With this treatment, GSH levels in liver, testis, caput epididymis, and cauda epididymis were elevated to 126%, 110%, 178%, and 136% of control values. Sexually mature male rats were then treated with NAC and challenged with a dose of EMS (100 mg/kg) to determine if enhanced tissue GSH would protect against EMS-induced dominant lethal mutations. Pretreatment with NAC significantly decreased the post-implantation loss from 7.05 +/- 0.57 with EMS alone to 5.28 +/- 0.47. Conversely, a dominant lethal assay was conducted using different doses of phorone pretreatment to determine the relative contribution of hepatic versus reproductive tract GSH in protecting against EMS-induced dominant lethal resorptions. Doses of 100 mg/kg and 250 mg/kg phorone significantly lowered both hepatic and reproductive tract GSH while 25 mg/kg lowered only hepatic GSH. These three dose levels were used as pretreatments in a dominant lethal study followed by a challenge administration of EMS (50 mg/kg), which is a threshold dose of EMS for producing dominant lethal mutations. Comparison against controls demonstrated a significant potentiation of fetal resorptions in all groups receiving phorone pretreatment, including the 25 mg/kg pretreatment group which only lowered hepatic GSH prior to EMS challenge. The results of these experiments indicate that GSH reserves in the male reproductive tract are insufficient to protect developing spermatozoa from damage by alkylating agents in the absence of hepatic GSH.

Mutagenic DNA repair in Escherichia coli, XX. Overproduction of UmuD' protein results in suppression of the umuC36 mutation in excision defective bacteria.

Overproduction of Umu+ or UmuD' protein by means of a gene carried on a multicopy plasmid suppressed the umuC36 phenotype and permitted induction of mutations by ultraviolet light. The umuC122::Tn5 phenotype was not suppressed. Suppression of the umuC36 phenotype was only seen when excision repair was blocked by acriflavine or by an uvrA or uvrB mutation. Cleavage of UmuD to UmuD' in SOS-induced cells was not dependent upon the presence of UmuC protein. The results are interpreted in terms of a revised model in which UmuC protein is envisaged as guiding UmuD' to RecA protein which has recognized and become bound to an appropriate DNA lesion. It is suggested that the umuC36 mutation gives rise to a protein with reduced affinity for UmuD' and that the effect of this can be compensated by an excess of UmuD'.

Mutagenic DNA repair in Escherichia coli. XIX. On the roles of RecA protein in ultraviolet light mutagenesis.

An experimental system was used in which His+ mutations induced by ultraviolet light (UV) arise from non-photo-reversible photoproducts whereas lethality is largely determined by photoreversible photoproducts. By exposing a strain with a deletion through recA to light immediately after UV, it was possible to examine mutagenesis under conditions where survival was not significantly different from 100%. No UV mutagenesis was seen in the absence of RecA protein even though the rest of the SOS system was fully expressed due to the presence of a defective LexA repressor and the active carboxy-terminal fragment of UmuD was present as a result of an engineered plasmid-borne gene. We conclude that RecA protein has a third essential function if UV mutagenesis is to be detected in excision-deficient-bacteria. Another experiment showed that in exerting this function RecA protein does not need activation by pyrimidine dimers elsewhere on the genome, in contrast to its protein-cleavage mediation functions with LexA and UmuD proteins. RecA1730 protein blocked UV mutagenesis unless delayed photoreversal was given showing that the third function of RecA protein is not in the misincorporation step. It is therefore most likely to be in the bypass step where UmuD' and UmuC are postulated to act, although the possibility cannot be excluded that RecA protein is required for some other survival function distinct from translesion synthesis.

Cytologic assessment of tumor cell kinetics: applications of monoclonal antibody Ki-67 to fine-needle aspiration smears.

Rates of tumor-cell proliferation often provide prognostic information about a given neoplasm. Previously available methods for accessing cell kinetics are time consuming and expensive, and often require special equipment or radioactive reagents. Monoclonal antibody Ki-67 binds a nuclear antigen expressed in proliferating but not in resting cells. We studied Ki-67 immunostaining of fine-needle aspiration smears from 40 benign and malignant masses. Labeling indices ranged from 0 (thyroid follicular adenoma) to 75 percent (pulmonary oat-cell carcinoma). Frozen section immunostaining (11 cases) and flow cytometric assessment of cell proliferation (8 cases) were in good agreement with Ki-67 labeling indices on smear material. We suggest that this method provides a rapid, inexpensive, and dependable means of assessing tumor-cell kinetics in cytologic preparations.

Developmental toxicity of soman in rats and rabbits.

Soman (GD; phosphonofluoridic acid, methyl-,1,2,2-trimethylpropyl ester) is an organophosphate compound with potent anticholinesterase activity. To determine developmental toxicity, soman was administered orally to CD rats on days 6 through 15 of gestation at dose levels of 0, 37.5, 75, 150, or 165 micrograms/kg/day and to New Zealand White (NZW) rabbits on days 6 through 19 of gestation at dose levels of 0, 2.5, 5, 10, or 15 micrograms/kg/day. At sacrifice, gravid uteri were weighed and examined for number and status of implants. Individual fetal body weights and external, visceral, and skeletal malformations were recorded. Mean maternal weight changes, fetal implantation status/litter, fetal weight, and fetal malformations/litter were compared between dose groups. Monitors for maternal toxicity were net body weight change, treatment weight change, mortality, and clinical signs of toxicity such as lethargy, ataxia, and tremors. Maternal rats and rabbits in the high-dose groups exhibited statistically significant increases in toxicity and mortality when compared to controls. There were no significant dose-related effects among dose groups in the prevalence of postimplantation loss, malformations, or in average body weight of live fetuses per litter. There was no evidence of increased prenatal mortality or fetal toxicity in the CD rat or NZW rabbit following exposure to soman, even at a dose that produced significant maternal toxicity.