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PubMed2006

Effect of fruit and vegetable intake on skin carotenoid detected by non-invasive Raman spectroscopy.

BACKGROUND: Epidemiologic studies found the inverse correlation between fruit and vegetable intake and the risk of cardiovascular disease, various cancers, insulin resistance, and other chronic conditions. Skin carotenoid levels are highly correlated with serum levels; however, the direct measurement of skin carotenoids is difficult to perform. Raman spectroscopy has been described as a highly sensitive, specific and accurate method of skin carotenoid detection. OBJECTIVE: The authors assessed the relation between fruit and vegetable intake and skin carotenoid levels measured by Raman spectroscopy. MATERIAL AND METHOD: Twenty-nine healthy volunteers were enrolled in the present study. Demographic data and fruit and vegetable intake were recorded. Skin carotenoid levels were measured by Raman spectroscopy and were reported as Skin Carotenoid Score (SCS). The data were compared and were reported as 3 groups based on the amounts of fruit and vegetable intake. RESULTS: There were no significant differences of age, body weight, height and body mass index among the groups. Mean skin carotenoid score of low fruit and vegetable intake (25,733 +/- 2,956) was significantly lower than SCS of moderate intake (31,333 +/- 4,792, p = 0.03) and high fruit and vegetable intake (35,125 +/- 6,081, p < 0.01). Mean SCS of underweight participants (29,250 +/- 4,621) was not significantly different from normal (33,384 +/- 6,614) and overweight participants (27,575 +/- 3,811), p = 0.06. CONCLUSION: Using Raman spectroscopy, the authors found that skin carotenoid levels were directly correlated with the degree of fruit and vegetable intakes. We suggest that Raman spectroscopy should be possible to replace the invasive chemical technique for the dermatologic carotenoid measurement.

Adult↗

PubMed1991

[Effect of emissions from the glass factory "Sudety" in Szczytna on the levels of lead and fluorine in selected vegetables and fruit collected in 1989].

The objective of these studies was to examine the lead and flurorine contents in vegetables and apples exposed to emission of these elements by the "Sudety" Glassworks in Szczytna (Wałbrzych voivodeship). After mineralization of plant material, lead was determined by atomic absorption spectrometry (AAS). Fluorine was isolated from plant material samples by microdiffusion and was assayed spectrophotometrically using its complex with alizarin. The results indicate that 68% of the vegetables display lead contents exceeding the polish standard (i.e. 0.3 mg Pb per 1 kg of vegetable wet weight). Lead contents are highest in the overground parts of some plants, e.g. onion, lettuce, sorrel and rhubarb. The standard is exceeded from 23 to 13 times. So high a vegetable contamination is due to objectionable location of the "Podzamcze" employees' plots of gardens in Szczytna, related to the close vicinity of the "Sudety" Glassworks, wind rose and traffic arteries. The fluorine level in the vegetables examined is not very high. Only 4 of the analysed 21 vegetables exhibited fluorine contents exceeding those admitted by the Council for Mutual Economic Aid (2.5 mg F per 1 kg of vegetable wet weight); they included: young beet leaves, parsley tops, lettuce and sorrel.

Air Pollutants↗

PubMed1991

[Values of nitrate and nitrite in selected vegetables and potatoes cultivated in the region of Puław].

Nitrate and nitrite contents were determined in selected vegetables and potatoes from plantations of individuals farmers, situated either in the vicinity of the Nitrogen Plant in Puławy or at a distance from this plant (control). Vegetables and potatoes both newly harvested and stored for 4 months in cellars were analysed. From farms selected by lot, samples of lettuce, cabbage, sauerkraut, beets, carrots and potatoes (all harvested in 1986 and 1987) were collected. Nitrate and nitrite contents were determined in 1215 plant samples. Nitrates were reduced on a cadmium column to nitrites, whereupon they were determined colorimetrically using sulphanilic acid and N-1-naphthylethylenediamine. This results showed that the nitrate contents are higher in the vegetables and potatoes cultivated in the region of the Nitrogen Plant, as compared with those from the Janowiec village distant from this plant (control). Differences in mean nitrate contents per 100 g dry matter were in years 1986 and 1987 for: lettuce 73%, 36%; cabbage 54%, 39%; beets 16%, 20%; carrots 51%, 29%; potatoes 77%, 36%, respectively. Moreover, the vegetables and potatoes grown in the region of the Nitrogen Plant, as compared with the control vegetables from the village located at a distance from this plant, displayed a greater percentage of samples with plants characterized by higher nitrate contents. The greater percentage of samples containing high nitrate levels, as well as the higher mean nitrate contents in vegetables and potatoes testify to the effect of the Nitrogen Plant on nitrate concentrations in the crops. In vegetables from both regions, the nitrite contents did not exceed 1 mg NaNO2/kg.(ABSTRACT TRUNCATED AT 250 WORDS)

Nitrates↗

PubMed1993

[Levels of copper and zinc in vegetables, fruit and cereal from areas differing in the degree of industrial pollution and from greenhouses].

The content of copper and zinc was determined in vegetables, fruit and cereals derived from areas exposed or non-exposed to industrial pollution and from greenhouses. The elements were determined after dry mineralization by atomic absorption spectrometry immediately from mineral solution. Copper and zinc were measured in 506 samples of vegetables, 101 fruit samples and 117 cereal samples. In the vegetables from areas not exposed to industrial pollution the copper content was from 0.10 to 6.69 mg/kg, and zinc content was from 1.10 to 27.90 mg/kg. In the vegetables from areas exposed to this pollution copper was found in amounts from 0.10 to 3.26 mg/kg and zinc from 0.88 to 27.90 mg/kg. In the vegetables from green-houses copper amounted to 0.14-1.20 mg/kg and zinc from 1.00 to 10.60 mg/kh. In fruit samples copper was found in amounts from 0.04 to 7.01 mg/kg and zinc from 0.60 to 17.30 mg/kg. In cereals copper ranged from 1.14 to 11.68 mg/kg and zinc from 7.20 to 72.07 mg/kg. Table I. Copper in vegetables, fruit and cereals from areas differing in the degree of industrial pollution and from greenhouses copper amounted to 0.14-1.20 mg/kg and zinc from 1.00 to 10.60 mg/kh. In fruit samples copper was found in amounts from 0.04 to 7.01 mg/kg and zinc from 0.60 to 17.30 mg/kg. In cereals copper ranged from 1.14 to 11.68 mg/kg and zinc from 7.20 to 72.07 mg/kg. Table I. Copper in vegetables, fruit and cereals from areas differing in the degree of industrial pollution and from greenhouses.

Copper↗

PubMed1996

Fruit and vegetable consumption and cancer mortality in the Caerphilly Study.

We investigated whether the consumption of fruit and vegetables lowered cancer mortality in a cohort of 2112 Welsh men ages 45-69 years (The Caerphilly Study), which was followed-up for 13.8 years. At baseline (between 1979 and 1983), participants completed a 56-item food frequency questionnaire from which the consumption of fruit and vegetables was calculated. Relative risks (RR) were estimated with Cox proportional hazard analysis, with death from various types of cancer as a dependent variable, and fruit, vegetables, vitamin C, beta-carotene, dietary fiber, and potential confounders as independent variables. Mean consumption of vegetables and fruit at baseline was 118 g/day and 83 g/day, respectively. During follow-up 114 men died from cancer, including 51 men who died from respiratory tract cancer and 45 men who died from digestive tract cancer. Fruit consumption and the intake of dietary fiber were inversely related to respiratory tract cancer, but after adjustment for potential confounders including age, smoking, and social class, the association with fruit consumption became nonsignificant. Vegetable and fruit consumption was, independently from other risk factors, inversely related to mortality from cancer of the digestive tract (P for trend = 0.021), mainly due to an inverse association with fruit consumption (RR for the highest quartile versus the lowest was 0.3; 95% CI, 0.1-0.8). Vitamin C, beta-carotene, and dietary fiber were not significantly associated with cancers of the digestive tract. Vegetable and fruit consumption was also inversely related to all-cause cancer mortality, and the strongest association was observed for fruit consumption (RR in the highest versus lowest quartile was 0.5; 95% CI, 0.3-1.0). Consumption of vegetables and particularly the consumption of fruit could considerably lower the risk of dying from cancer in middle-aged men.

Age Factors↗

PubMedDate not supplied

Association between pollen hypersensitivity and edible vegetable allergy: a review.

Over the last three decades several authors have described the existence of an association between sensitivity to different pollens and sensitivity to diverse edible vegetables. An association between ragweed pollinosis and hypersensitivity to Cucurbitaceae vegetables (e.g., watermelon, melon, cucumber) and banana has been reported. Other authors have found a relationship between birch pollinosis and sensitization to hazelnut, apple, carrot, potato, kiwi and other vegetables. Additionally, several papers have shown the association between mugwort pollinosis and sensitization to celery, carrot, spices, nuts, mustard and Leguminoseae vegetables. Later, some studies showed association between grass pollinosis and sensitization to tomato, potato, green- pea, peanut, watermelon, melon, apple, orange and kiwi. Finally, an association between sensitization to plantain pollen and melon hypersensitivity was also described. The association between pollinosis and edible vegetable sensitization has been explained by the combination of different hypotheses, such as the following: 1) presence of lectins in edible vegetables; 2) existence of IgE to carbohydrates of the glycoproteins (cross-reactive carbohydrate determinants); and, 3) existence of common allergens between pollens and edible vegetables. Up to now three allergens have been identified as responsible for cross-reactivity in these associations: profilin, a 14 kd protein that regulates actin; Bet v 1, the 18 kd birch pollen allergen; and a 60-69 kd allergen. It is important to study in depth these associated sensitizations and the common allergens responsible for them in order to improve diagnostic methods and treatment of these syndromes.

Allergens↗

PubMed1997

Multiple positive cis elements regulate the asymmetric expression of the SpHE gene along the sea urchin embryo animal-vegetal axis.

The mechanism that establishes the maternally determined animal-vegetal axis of sea urchin embryos is unknown. We have analyzed the cis-regulatory elements of the SpHE gene of Strongylocentrotus purpuratus, which is asymmetrically expressed along this axis, in an effort to identify components of maternal positional information. Previously, we defined a regulatory region that is sufficient to provide correct nonvegetal expression of a beta-galactosidase reporter gene (Wei, Z., Angerer, L. M., Gagnon, M. L., and Angerer, R. C., Dev. Biol. 171, 195-211, 1995). We have now analyzed this region intensively in order to determine if the spatial pattern is controlled by nonvegetal-positive activities or by vegetal-negative activities. The regulatory sequences, except the basal promoter, were mutated by either deletion or sequence replacement. None of these mutations resulted in ectopic beta-gal expression in vegetal cells, showing that no single negative cis element is responsible for the lack of vegetal SpHE transcription. Surprisingly, even short segments of the regulatory region containing only several identified cis elements also direct nonvegetal expression. Furthermore, the SpHE basal promoter functions effectively in vegetal cells in combination with cis-acting elements derived from the PMC-specific gene, SM50. We conclude that the spatial pattern of SpHE transcription is achieved by multiple positive activities concentrated in nonvegetal cells. The vegetal expression of SM50 also is regulated only by positive activities (Makabe, K. W., Kirchhamer, C. V., Britten, R. J., and Davidson, E. H., Development 121, 1957-1970, 1995). A chimeric promoter containing both SpHE and SM50 regulatory sequences is active ubiquitously, suggesting that these regulators are not reciprocally repressive. These observations suggest a model in which the SpHE and SM50 genes are activated by separate sets of positive maternal activities concentrated, respectively, in nonvegetal and vegetal domains of the early embryo.

Animals↗

PubMed2000

Animal-vegetal axis patterning mechanisms in the early sea urchin embryo.

We discuss recent progress in understanding how cell fates are specified along the animal-vegetal axis of the sea urchin embryo. This process is initiated by cell-autonomous, maternally directed, mechanisms that establish three unique gene-regulatory domains. These domains are defined by distinct sets of vegetalizing (beta-catenin) and animalizing transcription factor (ATF) activities and their region of overlap in the macromeres, which specifies these cells as early mesendoderm. Subsequent signaling among cleavage-stage blastomeres further subdivides fates of macromere progeny to yield major embryonic tissues. Zygotically produced Wnt8 reinforces maternally regulated levels of nuclear beta-catenin in vegetal derivatives to down regulate ATF activity and further promote mesendoderm fates. Signaling through the Notch receptor from the vegetal micromere lineages diverts adjacent mesendoderm to secondary mesenchyme fates. Continued Wnt signaling expands the vegetal domain of beta-catenin's transcriptional regulatory activity and competes with animal signaling factors, including BMP2/4, to specify the endoderm-ectoderm border within veg(1) progeny. This model places new emphasis on the importance of the ratio of maternally regulated vegetal and animal transcription factor activities in initial specification events along the animal-vegetal axis.

Animals↗

PubMed1989

Chronic vegetative state after severe head injury: clinical study; electrophysiological investigations and CT scan in 15 cases.

Fifteen cases of chronic vegetative state (CVS), following severe head injury and lasting for two years or more, are reported. Vegetative state, in most instances after a period of coma, consists of a return of wakefulness accompanied by an apparent total lack of higher mental activity. A protracted period of vegetative state has been chosen to ensure that the possibility of further recovery could virtually be excluded. The term of CVS could therefore be reasonably used to designate these cases. Moreover, cerebral lesions were then thought to be the same as in neuropathological studies. Severe head injury, responsible for CVS, initially affected adults in 11 cases and children in four cases. The range of duration of the vegetative state was 2 to 14 years, with a mean of five years. The data of clinical study and electrophysiological investigations (EEG, brain stem auditory evoked potentials, somatosensory evoked potentials) are reported. A CT scan was carried out in each case to study the impairment of cerebral hemispheres and brain stem, with particular attention to the ventricular size. The results confirm that in the CVS, lesions affect mainly the hemispheres, while brain stem functions are mainly preserved. Vegetative State (VS) is the term proposed by Jennett and Plum (1972) to describe the condition that sometimes emerges after a period of coma, after a severe head injury (SHI). This condition consists of a return of wakefulness accompanied by an apparent total lack of higher mental activity. A practical definition of this state characterised by wakefulness without responsiveness is that the eyes open spontaneously and/or in response to verbal stimuli. Sleep-wake cycles exist. The patients can neither obey simple orders nor locate painful stimuli. They utter no comprehensible words. Blood pressure and breathing remain steady. It is much more difficult to specify exactly how long such a state must persist before it can be confidently declared permanent. Persistent vegetative state, or chronic vegetative state (CVS) is one of the five categories of the Glasgow Outcome Scale (Jennett and Bond, 1975). Bricolo et al (1980) think that the term CVS should never be applied before completion of the first year after the onset of traumatic coma. It actually seems possible to exclude the possibility of any further recovery after unresponsiveness for one year. The term CVS may then be rightfully used to denote this condition. For such protracted periods of VS, we have tried to state in a retrospective study the clinical and electroencephalographic (EEG) course.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗

PubMed2003

Vegetation type conversion in Los Peñasquitos Lagoon, California: an examination of the role of watershed urbanization.

The objective of this study was to examine the role that watershed urbanization has played in changes to the vegetation types within Los Peñasquitos Lagoon, San Diego, California. Aerial photographs taken between 1928 and 1999 were used to examine changes in vegetation types. The aerial photographs were scanned into digital format and incorporated into a geographic information system (GIS). A combination of image classification techniques was used to differentiate the vegetation types. Land use/cover of the Carmel Valley watershed of the Los Peñasquitos Lagoon was mapped for the same dates as the aerial photographs. A temporal geographic analysis was conducted on the conversion of areal extent of lagoon vegetation types compared to areal extent of urban development in the watershed. Soil salinity and dry season (June-September) stream discharge were measured. The results show that approximately 80.3% of the vegetation in the study area has changed types between 1928 and 1999. Increases in the areal extent of urban development within the watershed show a strong positive relationship compared to the areal extent of brackish marsh and riparian vegetation, and a strong negative relationship to the areal extent of salt panne and mudflats. There was no significant relationship between urban development and salt marsh vegetation.Dry season stream discharge has increased by an order of magnitude. The increase in stream discharge supports the hypothesis that increased freshwater has lowered soil salinity, allowing for invasion by glycophytic species. Hydrology and soil salinity appear to be significant factors for maintaining the distribution of the lagoon vegetation types and the biotic communities that rely upon them.

California↗

PubMed2006

Initial adjustments within a new river channel: Interactions between fluvial processes, colonizing vegetation, and bank profile development.

A conceptual model of the morphological development of the riparian margins of newly cut river channels is presented, suggesting early feedbacks between vegetation growth and bank form. To test the model, observations of long and cross profiles, bank sediment and seed deposition, and bank vegetation development were collected over the first 2 years of river flows through a reach of the River Cole, West Midlands, UK. The newly created channel had a sinuous planform and varying asymmetric trapezoidal cross section in sympathy with the planform. No imposed bedforms or bank reseeding were included in the design. Over the 2 years, development of bedforms was rapid, with bed sediment sorting and bank profile adjustment occurring more steadily and progressively. Six classes of bank profile were identified by the end of the study period, illustrating close associations with sediment aggradation, vegetation colonization, and growth patterns. Vegetation colonization of the banks was seeded predominantly from local sources during the summer and from hydrochory (transport by the river) during the winter. Colonizing vegetation on the riverbanks appeared to act as a significant propagule source by the second summer and as an increasingly important roughness element, trapping both propagules and sediment, within the second year and providing early feedback into bank evolution. As a result, the time required for riparian margin development in the conceptual model was found to be considerably longer than observed in the study river. In addition, the role of surface wash/bank failure in modifying the bank profile and transporting seeds onto the upper bank face during the first year of bank development was found to be important in initiating rapid bank vegetation colonization and surface stabilization. This set of processes had not been incorporated in the initial conceptual model. In relation to channel restoration, this research illustrates that in small temperate rivers of modest energy the provision of an initial, sinuous corridor is sufficient to induce rapid development of fluvial features and vegetation cover without the need to construct bed forms or to seed the banks.

Conservation of Natural Resources↗

PubMed2006

Vegetative reproduction and clonal diversity in Rhytidium rugosum (Rhytidiaceae, Bryopsida) inferred by morpho-anatomical and molecular analyses.

Many bryophytes exhibit specific life forms that result in the formation of distinct patches. This is primarily achieved by "consequent vegetative multiplication" through indeterminate growth and vegetative reproduction. Little, however, is known about the underlying mechanisms and genetic patterns. In this study on vegetative multiplication in bryophytes, we apply morpho-anatomical and molecular (AFLP fingerprinting) techniques to analyze the vegetative reproduction system, clonal diversity, and habitat colonization of a pleurocarpous moss, Rhytidium rugosum (Rhytidiaceae). Morpho-anatomically, three types of vegetative diaspores are identified and illustrated: ramets, separated after decay and disintegration of older shoot parts (clonal reproduction); brood branches/branchlets; and caducous shoot apices (both vegetative reproduction s.str.). The AFLP fingerprinting of 35 samples (from two plots in Thuringia, further German populations, and from France, Russia, and Canada) resulted in the identification of three clones from the two plots, each comprising two to 15 samples with identical fingerprints. Samples from one clone occurred in both plots, thus proving dispersal of vegetative diaspores. The AFLP analysis further revealed close relationships of the plot samples, which suggest a clonal rather than generative (sexual) origin of the population.

Bryopsida↗

PubMed2005

Vegetation mapping for change detection on an arid-zone river.

A vegetation mapping system for change detection was tested at the Havasu National Wildlife Refuge (HNWR) on the Lower Colorado River. A low-cost, aerial photomosaic of the 4200 ha, study area was constructed utilizing an automated digital camera system, supplemented with oblique photographs to aid in determining species composition and plant heights. Ground-truth plots showed high accuracy in distinguishing native cottonwood (Populus fremontii) and willow (Salix gooddingii) trees from other vegetation on aerial photos. Marsh vegetation (mainly cattails, Typha domengensis) was also easily identified. However, shrubby terrestrial vegetation, consisting of saltcedar (Tamarix ramosissima), arrowweed (Pluchea sericea), and mesquite trees (Prosopis spp.), could not be accurately distinguished from each other and were combined into a single shrub layer on the final vegetation map. The final map took the form of a base, shrub and marsh layer, which was displayed as a Normalized Difference Vegetation Index map from a Landsat Enhanced Thematic Mapper (ETM+) image to show vegetation intensity. Native willow and cottonwood trees were digitized manually on the photomosaic and overlain on the shrub layer in a GIS. By contrast to present, qualitative mapping systems used on the Lower Colorado River, this mapping system provides quantitative information that can be used for accurate change detection. However, better methods to distinguish between saltcedar, mesquite, and arrowweed are needed to map the shrub layer.

Desert Climate↗

PubMed2005

Assessment of MODIS-EVI, MODIS-NDVI and VEGETATION-NDVI composite data using agricultural measurements: an example at corn fields in western Mexico.

Although several types of satellite data provide temporal information of the land use at no cost, digital satellite data applications for agricultural studies are limited compared to applications for forest management. This study assessed the suitability of vegetation indices derived from the TERRA-Moderate Resolution Imaging Spectroradiometer (MODIS) sensor and SPOT-VEGETATION (VGT) sensor for identifying corn growth in western Mexico. Overall, the Normalized Difference Vegetation Index (NDVI) composites from the VGT sensor based on bi-directional compositing method produced vegetation information most closely resembling actual crop conditions. The NDVI composites from the MODIS sensor exhibited saturated signals starting 30 days after planting, but corresponded to green leaf senescence in April. The temporal NDVI composites from the VGT sensor based on the maximum value method had a maximum plateau for 80 days, which masked the important crop transformation from vegetative stage to reproductive stage. The Enhanced Vegetation Index (EVI) composites from the MODIS sensor reached a maximum plateau 40 days earlier than the occurrence of maximum leaf area index (LAI) and maximum intercepted fraction of photosynthetic active radiation (fPAR) derived from in-situ measurements. The results of this study showed that the 250-m resolution MODIS data did not provide more accurate vegetation information for corn growth description than the 500-m and 1000-m resolution MODIS data.

Crops, Agricultural↗

PubMed1982

Diagnostic accuracy of M-mode echocardiography in active infective endocarditis and prognostic implications of ultrasound-detectable vegetations.

Sensitivity, specificity, diagnostic accuracy, and prognostic implications of the M-mode echocardiographic pattern of vegetations were examined prospectively in consecutive patients referred with potential active infective endocarditis (IE). A pattern of definite echo vegetations was present in 37% of 51 patients diagnosed clinically to have active IE. Specificity in 138 patients without IE was 96%. Diagnostic accuracy of a positive test was 76% and that of a negative test was 80%. Five of six false positive studies involved patients with prior IE or valvular thrombosis. If possible echo vegetations were included, sensitivity increased to 47% and specificity decreased to 89%. Echographic vegetations were significantly correlated with congestive heart failure and need for valve replacement and/or death. Seven of eight patients with definite aortic valve vegetations died or required surgery, compared with 1 of 11 patients with mitral or tricuspid vegetations alone. Prognostic importance of echocardiographically documented vegetations appears to depend upon their site within the heart.

Adult↗

PubMed1980

The demonstration of vegetations by echocardiography in bacterial endocarditis. An indication for early surgical intervention.

The visualization of vegetations by M-mode echocardiography in patients with infective endocarditis has been suggested to imply a poor prognosis regarding the development of major systemic emboli, congestive heart failure and the need for early surgical intervention. The question of using the finding of vegetations by echocardiography as an indication for surgery is controversial. To answer this question, 30 patients with the clinical diagnosis of endocarditis were studied by echocardiography. In 17 of the 30 (57 per cent) vegetations were present (aortic eight, mitral four, both mitral and aortic five), whereas in 13 (43 per cent) no vegetations were visualized. Infecting organisms were similar in each group; Streptococcus viridans being the most common. The patients with echocardiographically demonstrable vegetations had a higher incidence of congestive heart failure compared to the patients without (14 of 17 versus six of 13, p less than 0.05), major emboli (eight of 17 versus two of 13, p = NS) and need for valve surgery (17 of 17 versus two of 13, p less than 0.001). Mortality was not significantly different in the two groups (six of 17 versus three of 13, p = NS). Urgent or emergency surgery was required in 16 of 17 patients with vegetations. Thus, the demonstration of vegetations by echocardiography identified a subset of patients with more severe disease in whom early operative intervention was required.

Adult↗

PubMed1987

Differentiation of the animal-vegetal axis in Xenopus laevis oocytes. I. Polarized intracellular translocation of platelets establishes the yolk gradient.

The animal-vegetal axis of the oocyte of Xenopus laevis is recognizable not only by the pattern of surface pigmentation, but also by the distribution of yolk platelets, with the largest platelets (congruent to 14 microns in diameter) and 70% of the total yolk protein localized in the vegetal hemisphere. We have used fluorescent and radioactive vitellogenins (yolk protein precursors) to study the spatial and temporal patterns of yolk deposition along this axis. We find that the rate of uptake of vitellogenin is nearly uniform over the surface of vitellogenic oocytes of all sizes. Once formed, yolk platelets in the animal hemisphere move inward, around the germinal vesicle, and into the central region of the vegetal hemisphere. Yolk platelets of the vegetal hemisphere do not actively move but are slowly displaced from the surface by successive layers of younger platelets arising and enlarging near the surface. The oldest yolk platelets, which arise circumcortically at the beginning of vitellogenesis in stage II and III oocytes, eventually come to reside in the vegetal hemisphere of stage VI oocytes, in the upper portion of the cup-shaped region of largest platelets. The vegetal hemisphere thus gains the majority of yolk protein by directed intracellular transport from the animal hemisphere adding to the amount directly sequestered by the vegetal hemisphere.

Animals↗

PubMed1978

Mutation induction with UV- and X-radiations in spores and vegetative cells of Bacillus subtilis.

Spores and vegetative cells of Bacillus subtilis strains with various defects in DNA-repair capacities (hcr-, ssp-, hcr-ssp-) were irradiated with UV radiation or X-rays. Induced mutation frequency was determined from the observed frequency of prototrophic reversion of a suppressible auxotrophic mutation. At equal physical dose, after either UV- or X-irradiation, spores were more resistant to mutations as well as to killing than were vegetative cells. However, quantitative comparison revealed that, at equally lethal doses, spores and vegetative cells were almost equally mutable by X-rays whereas spores were considerably less mutable by UV than were vegetative cells. Thus, as judged from their mutagenic efficiency relative to the lethality, X-ray-induced damage in the spore DNA and the vegetative DNA were equally mutagenic, while UV-induced DNA photoproducts in the spore were less mutagenic than those in vegetative cells. Post-treatment of UV-irradiated cells with caffeine decreased the survival and the induced mutation frequency for either spores or vegetative cells for all the strains. In X-irradiated spores, however, a similar suppressing effect of caffeine was observed only for mutability of a strain lacking DNA polymerase I activity.

Bacillus subtilis↗