Cisplatin-induced hyperglycemic hyperosmolar coma

We present a case of severe hyperglycaemic hyperosmolar derangement after treatment with cisplatin in a patient without previous diabetes mellitus. Limited data are available on this adverse reaction, explaining why impaired glucose handling due to cisplatin is not generally recognised.

KINKY POLLEN encodes a SABRE-like protein required for tip growth in Arabidopsis and conserved among eukaryotes

In higher plants, pollen tubes and root hairs share an ancient growth process named tip growth. We have isolated three allelic Arabidopsis mutant lines showing kinky-shaped pollen tubes and, when homozygous, showing shorter and thicker root hairs. The ultrastructure of pollen tubes in these kinky pollen (kip) mutants is similar to that of the wild type; however, time-lapse studies suggest that aberrant pollen tube shape is caused by periodic growth arrests alternated with phases of tube axis reorientation. The KIP gene encodes a protein of 2587 amino acids that is predicted to be targeted to the secretory pathway. KIP mRNA was detected in all organs investigated but was most abundant in pollen and roots. KIP has putative homologues in many eukaryotes, including mammals and yeast, and is similar to the Arabidopsis SABRE gene, whose mutation causes a dwarf phenotype. The phenotype of the kip/sab double mutant suggests related functions for both genes, however, the KIP protein is mostly required for tip-growth.

Ethylene regulates the timing of anther dehiscence in tobacco

We investigated the involvement of ethylene signaling in the development of the reproductive structures in tobacco ( Nicotiana tabacum L.) by studying flowers that were insensitive to ethylene. Ethylene-insensitivity was generated either by expression of the mutant etr1-1 ethylene-receptor allele from Arabidopsis thaliana or by treatment with the ethylene-perception inhibitor 1-methylcyclopropene (MCP). Development of ovaries and ovules was unaffected by ethylene-insensitivity. Anther development was also unaffected, but the final event of dehiscence was delayed and was no longer synchronous with flower opening. We showed that in these anthers degeneration of the stomium cells and dehydration were delayed. In addition, we found that MCP-treatment of detached flowers and isolated, almost mature anthers delayed dehiscence whereas ethylene-treatment accelerated dehiscence. This indicated that ethylene has a direct effect on a process that takes place in the anthers just before dehiscence. Because a similar function has been described for jasmonic acid in Arabidopsis, we suggest that ethylene acts similarly to or perhaps even in concurrence with jasmonic acid as a signaling molecule controlling the processes that lead to anther dehiscence in tobacco.

Characterization and localization of the transmitting tissue-specific PELPIII proteins of Nicotiana tabacum

The class III pistil-specific PELP proteins (PELPIII) of Nicotiana tabacum includes at least two members of highly soluble glycoproteins containing glucan modules that are characteristic for arabinogalactan proteins (AGPs). PELPIII accumulates in the style transmitting tissue (TT) during pistil development and, at flower anthesis, is present in the intercellular matrix (IM) of non-pollinated pistils. After pollination, PELPIII appears to be directly and completely translocated from the IM into the pollen tube callose walls, no significant accumulation was observed in the primary wall in the tip. In the spent parts of the pollen tubes these proteins become detectable against the remnants of the tube cell membrane and in the callose plugs. Different protein extraction procedures of PELPIII from pollinated tobacco pistils showed that these proteins remain in the highly soluble protein fraction and are not modified by the growing pollen tubes. These data concur with a role in IM development and pollen tube growth. In addition, the data show that the PELPIII are able to reach the cell membrane, facilitated by an already present or induced high porosity of the tube wall and an additional, yet unknown, mechanism. The differences in behaviour between the three related classes of style IM glycoproteins of Nicotiana, namely, PELPII, TTS and the 120 kDa glycoprotein, are proposed to connect more to their differences in glycosylation than to major differences in amino acid sequence.

Description of a cellulose-binding domain and a linker sequence from Aspergillus fungi

A family I cellulose-binding domain (CBD) and a serine- and threonine-rich linker peptide were cloned from the fungi Aspergillus japonicus and Aspergillus aculeatus. A glutathione S-transferase (GST) fusion protein comprising GST and a peptide linker with the CBD fused to its C-terminus, was expressed in Escherichia coli. The renatured GST-CBD recovered from inclusion bodies had a molecular mass of 36.5 kDa which agrees with the 29 kDa of the GST plus the calculated 7.5 kDa of the linker with the CBD. The isolated GST-CBD protein adsorbed to both bacterial microcrystalline cellulose and carboxymethyl cellulose. Deletion of the linker peptide caused a decrease in cellulose adsorbance and a higher sensitivity to protease digestion.

Class III pistil-specific extensin-like proteins from tobacco have characteristics of arabinogalactan proteins

Class III pistil-specific extensin-like proteins (PELPIII) are specifically localized in the intercellular matrix of tobacco (Nicotiana tabacum) styles. After pollination the majority of PELPIII are translocated into the callosic layer and the callose plugs of the pollen tubes, which could suggest a function of PELPIII in pollen tube growth. PELPIII may represent one of the chemical and/or physical factors from the female sporophytic tissue that contributes to the difference between in vivo and in vitro pollen tube growth. PELPIII glycoproteins were purified and biochemically characterized. Because of their high proline (Pro) and hydroxy-Pro (Hyp) content, PELPIII proteins belong to the class of Pro/Hyp-rich glycoproteins. The carbohydrate moiety of PELPIII is attached through O-glycosidic linkages and comprises more than one-half the total glycoprotein. Deglycosylation of PELPIII revealed two backbones, both reacting with PELPIII-specific antibodies. N-terminal amino acid sequencing of these backbones showed that PELPIII is encoded by the MG14 and MG15 genes. Two heterogeneous N-terminal sequences of MG14 and MG15, both starting downstream of the predicted signal peptide cleavage site, seem to be present, which indicates a novel N-terminal processing. Monosaccharide analysis showed that the carbohydrate moiety of PELPIII almost completely consists of arabinose and galactose in an equal molar ratio. Carbohydrate linkage analysis showed terminal and 2-linked arabinofuranosyl residues, as well as terminal and 6-, 3-, and 3,6-linked galactopyranosyl residues to be present, indicating the presence of both extensin-like and Type II arabinogalactan oligosaccharide units. The ability of beta-glucosyl Yariv reagent to bind with PELPIII confirmed the arabinogalactan protein-like characteristics of these proteins.

Changes in cell wall polysaccharides of green bean pods during development

The changes in cell wall polysaccharides and selected cell wall-modifying enzymes were studied during the development of green bean (Phaseolus vulgaris L.) pods. An overall increase of cell wall material on a dry-weight basis was observed during pod development. Major changes were detected in the pectic polymers. Young, exponentially growing cell walls contained large amounts of neutral, sugar-rich pectic polymers (rhamnogalacturonan), which were water insoluble and relatively tightly connected to the cell wall. During elongation, more galactose-rich pectic polymers were deposited into the cell wall. In addition, the level of branched rhamnogalacturonan remained constant, while the level of linear homogalacturonan steadily increased. During maturation of the pods, galactose-rich pectic polymers were degraded, while the accumulation of soluble homogalacturonan continued. During senescence there was an increase in the amount of ionically complexed pectins, mainly at the expense of freely soluble pectins. The most abundant of the enzymes tested for was pectin methylesterase. Peroxidase, beta-galactosidase, and alpha-arabinosidase were also detected in appreciable amounts. Polygalacturonase was detected only in very small amounts throughout development. The relationship between endogenous enzyme levels and the properties of cell wall polymers is discussed with respect to cell wall synthesis and degradation.

Rational analyses of organelle trajectories in tobacco pollen tubes reveal characteristics of the actomyosin cytoskeleton

To gain insight into the characteristics of organelle movement and the underlying actomyosin motility system in tobacco pollen tubes, we collected data points representing sequential organelle positions in control and cytochalasin-treated cells, and in a sample of extruded cytoplasm. These data were utilized to reconstruct approximately 900 tracks, representing individual organelle movements, and to produce a quantitative analysis of the movement properties, supported by statistical tests. Each reconstructed track appeared to be unique and to show irregularities in velocity and direction of movement. The regularity quotient was near 2 at the tip and above 3 elsewhere in the cell, indicating that movement is more vectorial in the tube area. Similarly, the progressiveness ratio showed that there were relatively more straight trajectories in the tube region than at the tip. Consistent with these data, arithmetical dissection revealed a high degree of randomlike movement in the apex, lanes with tip-directed movement along the flanks, and grain-directed movement in the center of the tube. Intercalated lanes with bidirectional movement had lower organelle velocity, suggesting that steric hindrance plays a role. The results from the movement analysis indicate that the axial arrangement of the actin filaments and performance of the actomyosin system increases from tip to base, and that the opposite polarity of the actin filaments in the peripheral (+-ends of acting filaments toward the tip) versus the central cytoplasm (+-ends of actin filaments toward to the grain) is installed within a few minutes in these tip-growing cells.

[A diabetic patient with cystitis emphysematosa]

In a woman aged 80 years arriving in the Emergency Room with progressive malaise, anorexia and somnolence, a large resistance was found in the lower abdomen, which proved to be due to cystitis emphysematosa. The patient was known to suffer from non-insulin dependent diabetes mellitus. Imaging revealed a large accumulation of gas in the urinary bladder, which was treated successfully with catheterization and antibiotics. Cystitis emphysematosa is a rare condition, characterized by collection of gas in the bladder and bladder wall and brought about by gas-forming micro-organisms that decompose glucose. In patients with diabetes mellitus optimal regulation of the blood glucose levels, with a view to preventing glycosuria, is a condition of speedy recovery. Although cases with a fatal outcome have been reported, the prognosis in general is favourable.

Interactive computer-assisted position acquisition procedure designed for the analysis of organelle movement in pollen tubes

An interactive computer-assisted video microscopy method has been developed for the acquisition of extensive data on the sequential positions of pollen tube organelles, which cannot be automatically tracked using geometric or motion patterns. The method consists of video microscopy, analog and digital contrast enhancement, digital time-lapsing of the images, and interactive selection of positions in a coordinate system corresponding to the cell shape and real size. Data on 15,000 positions acquired with this method have been used to make quantitative analyses of the movement patterns of the organelles. From these analyses and the reconstruction of 900 trajectories, it appears that movements are random in the tip of the pollen tube but become more directed in distal regions of the cell, indicating an increase in axial arrangement of the actin filaments. (All custom-made software is available from the authors on request.)

Classification of organelle trajectories using region-based curve analysis

A method based on analysis of the region of movement and the functioning of the acto-myosin cytoskeleton has been elaborated to quantify and classify patterns of organelle movement in tobacco pollen tubes. The trajectory was dilated to the region of movement, which was then reduced to give a one-pixel-wide skeleton, represented by a graph structure. The longest line in this skeleton was hypothesized to represent the basic track of the organelle along a single actin filament. Quantitative features were derived from the graph structure, direction of movement on the longest skeletal line, and distance between skeletal line and particle. These features corresponded to biological events like the amount of linear movement or the probability of attachment of an organelle to the actin filament. From 81 analyzed organelle trajectories, 17 had completely linear, 17 had completely non-linear, and 47 had alternating linear and non-linear movement. Selected features were employed for classification and ranking of the movement patterns of a representative sample of the population of organelles moving in the cell tip. The presented methods can be applied to any field where analysis and classification of particle motion are intended.

Carcinoid tumor of the jugulo-tympanic region

Increased levels of 5-hydroxyindole acetic acid (5-HIAA) were found in a patient with a tumor arising in the middle ear. Iodine-123-metaiodobenzylguanidine ([123I]MIBG) scintigraphy and biochemical analysis showed evidence of serotonin production by the tumor. Immunohistochemistry of the tumor showed reactivity with antibodies directed against serotonin, chromogranin, leu-7 and neuron-specific enolase; S-100, met-enkephalin, leu-enkephalin and glial fibrillary acid protein were negative. This case suggests a close relationship between functioning paragangliomas and carcinoid tumors because a strong clinical and endocrinological resemblance exists. The hormonal activity found is discussed in relation to extra-adrenal paragangliomas. We recommend urinary screening not only for detection of increased levels of catecholamines, but also of 5-HIAA in all patients with paragangliomas of the head and neck. When elevated levels are found, [123I]MIBG scintigraphy should be performed to localize the areas of increased uptake in or outside the head and neck region.

A case of 16-ene-synthetase deficiency in male pseudohermaphroditism due to combined 17 alpha-hydroxylase/17,20-lyase deficiency

A 17-year-old phenotypic female with primary hypergonadotropic amenorrhea, absence of secondary sexual development, hypertension and 46 XY karyotype is presented. Hormonal analysis revealed very low levels of testosterone, dehydroepiandrosterone, androstenedione, estrogens, cortisol and high levels of ACTH, progesterone, deoxycorticosterone and corticosterone. Enzyme studies of the testicular tissue after bilateral gonadectomy showed absence of 17 alpha-hydroxylase and 17,20-lyase activity as well as 16-ene-synthetase activity. This enzyme catalyzes the reaction from pregnenolone to 5,16-androstadien-3 beta-ol, a sex pheromone precursor. The other enzyme systems leading from pregnenolone to testosterone were intact. This is the first report of male pseudohermaphroiditism in which the combination of 17 alpha-hydroxylase, 17,20-lyase and 16-ene-synthetase deficiency is described, indicating that all these activities might be associated with the same protein.

Identification of virilizing adrenal tumors in hirsute women

BACKGROUND

Hirsutism in women is usually caused by benign adrenal or ovarian disorders, but it can also be caused by adrenal carcinoma. The most effective way to identify such carcinomas is not known.

METHODS

We measured serum and urinary steroids before and after the administration of 3 mg of dexamethasone per day for five days in 14 hirsute women with histologically proved adrenal tumors (12 adrenal carcinomas and 2 adrenal adenomas) and in 73 women with hirsutism of non-neoplastic origin.

RESULTS

All the women with adrenal tumors had elevated basal serum concentrations of testosterone or dehydroepiandrosterone sulfate, as compared with 36 of the 73 women with non-neoplastic hirsutism (sensitivity, 100 percent; 95 percent confidence interval, 77 to 100; specificity, 50 percent; 95 percent confidence interval, 38 to 62). After the administration of dexamethasone, serum dehydroepiandrosterone sulfate concentrations and urinary 17-ketosteroid excretion decreased to values similar to those in normal women in all the women with non-neoplastic hirsutism, but in none of the 12 with adrenal tumors who were tested. All the women who did not have adrenal tumors had serum cortisol concentrations below 3.3 micrograms per deciliter (90 nmol per liter) after dexamethasone administration, whereas in all 12 patients tested who had tumors the values were higher. The suppression of serum dehydroepiandrosterone sulfate and cortisol and urinary 17-ketosteroid excretion excluded the likelihood of adrenal tumors with a sensitivity of 100 percent (95 percent confidence interval, 74 to 100) and a specificity of 100 percent (95 percent confidence interval, 89 to 100).

CONCLUSIONS

Among women with hirsutism, an adrenal tumor is unlikely if the patient has normal basal serum concentrations of testosterone and dehydroepiandrosterone sulfate. In women in whom these concentrations are elevated, a tumor is unlikely if the serum concentration of dehydroepiandrosterone sulfate and urinary 17-ketosteroid excretion are in the normal basal range and the serum cortisol concentration is less than 3.3 micrograms per deciliter after the administration of dexamethasone.

Dehydroepiandrosterone sulphate (DHEAS) in the oldest old, aged 85 and over

Dehydroepiandrosterone (DHEA) and its sulphonated metabolite DHEAS are the major secretory products of the human adrenal gland. Despite the abundancy of these steroids in the circulation the precise function is uncertain. It has been postulated that they may be involved in the maturing and aging processes in man. An intriguing inverse relation has been described between DHEAS and cardiovascular mortality in men. In women from the same population this was not the case and in fact mortality due to cardiovascular disease was highest in women with the highest levels of DHEAS. Another interesting association is reported between DHEA and DHEAS and the enhancement of memory retention in mice. Reduced plasma concentration of DHEAS have been described in patients with Alzheimer's disease compared with age-matched controls. In the framework of a gerontologic study concerning all 1259 inhabitants aged 85 years and over of the Dutch community of Leiden (population +/- 105,000), DHEAS levels were determined in 138 subjects of this cohort. Of these, 53 were healthy subjects, selected from the population according to the health criteria of the SENIEUR protocol, which is based on clinical, pharmacological and laboratory data. This enabled us to assess reference values for this age group. Additionally DHEAS levels were measured in 64 young controls, 20-40 years of age, who also fulfilled these criteria. Reference values for the oldest old, derived from the healthy group, are 1.7 +/- 1.4 mumol/l for women and 2.2 +/- 1.1 mumol/l for men. DHEAS levels decreased fourfold between the young adults and those aged 85 and over. In men this decrease continued after the age of 85. DHEAS values tended to be higher in men than in women, both in the elderly, in all subgroups of elderly subjects, and in the young control group, but this sex-difference did not reach statistical significance. No difference was found between the DHEAS levels in subgroups according to the health status, the survival rate or the diagnosis of probable Alzheimer's disease. Many uncertainties concerning the role of DHEAS in the neuro-immuno-endocrinological network have yet to be unravelled and the question remains whether the age-related decrease of DHEAS is related to organ-specific failure on the level of the adrenals or the gonads, or whether it is a result of changes in feedback or regulatory mechanisms. DHEAS is one of the few compounds that shows a gradual decrease with advancing age, reaching an asymptotic low at the age of the maximum recorded life span.(ABSTRACT TRUNCATED AT 400 WORDS)

Studies of the role of the propeptides of the Arabidopsis thaliana 2S albumin

To investigate the possible roles of the Arabidopsis thaliana 2S albumin propeptides with respect to sorting, processing, and stability of the protein in plant cells, five gene constructions deleting or modifying the propeptides were made based on one of the genes encoding the Arabidopsis 2S albumin. These constructions were introduced into tobacco (Nicotiana tabacum) plants. Using subcellular fractionation and immunocytochemistry on ripe seeds, it was demonstrated that none of the propeptides was necessary for the sorting of the protein. Detailed protein-chemical analysis of the mature gene products indicated that, for all of the modified 2S albumin precursors made, the proteins were stably folded and correctly processed. However, the latter is less efficient when the internal fragment between the small and the large subunit is missing or when this internal fragment is changed. In an attempt to establish a rapid assay system for modified 2S albumin precursors, yeast cells were transformed with the same gene constructs. It was demonstrated that the processing machinery in yeast cells differs from that in plants, and, in a perhaps related observation, differences in stability of a particular modified protein were observed.

Semiquantitative assessment of hirsutism in Dutch women

Many doctors frequently encounter hirsute patients. Quantification of hair growth may be useful for diagnosis and follow-up. To establish the reference range for distribution and density of hair in females, and to determine the regions yielding the best discrimination between normal and hirsute women, we studied the distribution and density of terminal hair on 12 body regions assessed on a scale of 0-4. Prospectively, 81 healthy female volunteers and 71 hirsute patients of child-bearing age and Dutch ancestry, who were not receiving medication, and who had not had a recent pregnancy were studied. The reference hair pattern was established for each body region, and the threshold value yielding the highest sensitivity and specificity to evaluate hirsutism was calculated. None of the women in the reference population displayed a score of more than 1 for chin, upper back, upper abdomen and upper arm, or more than 2 for upper lip, side-burns, chest, lower back, lower abdomen, thighs or forearm. The best discrimination between the reference and hirsute populations was obtained with the sum of the scores for four regions: upper lip, chin, lower abdomen and thighs. Independent assessment of hair growth by two investigators revealed excellent agreement. We conclude that a score of more than 1 for chin, upper back, upper abdomen and upper arm, or more than 2 for upper lip, side-burns, chest, lower back, lower abdomen, thighs or forearm is abnormal for Dutch women, and that assessment of hair growth on the upper lip, chin, lower abdomen and thighs is the most suitable way to evaluate hirsutism.

Measurement of trunk bending during work by direct observation and continuous measurement

An observational method and a continuous measurement technique were simultaneously applied to record bending of the trunk during work. In a group of 16 workers performing dynamic tasks a significant correlation (r = 0.57) was found between the two methods. A similar result was observed among 14 sedentary workers (r = 0.62). Although significant correlations between direct observation and continuous recording techniques were present, large differences were found between data obtained from individual subjects. The results cast doubt on the validity of assessments of percentage of worktime with bent trunk at an absolute level using only one measurement method. It is suggested that greater consideration has to be given in future studies to the reliability of measurement of postural load due to trunk bending.

Orientation of cellulose microfibrils in cortical cells of tobacco explants : Effects of microtubule-depolymerizing drugs

The deposition of nascent cellulose microfibrils (CMFs) was studied in the walls of cortical cells in explants of Nicotiana tabacum L. flower stalks. In freshly cut explants the CMFs were deposited in two distinct and alternating orientations - all given with respect to the longitudinal axis of the cell -, at 75° and 115°, in a left-handed (S-helix) and right-handed (Z-helix) form, respectively. The CMFs deposited in these orientations did not form uninterrupted layers, but sheets in which both orientations were present. After explantation, the synthesis of CMFs and their deposition in bundles continued. New orientations occurred within 6 h. After 6 h a new sheet was deposited, with orientations of 15° (S-helix) and 165° (Z-helix). The changes could be seen as sudden bends in individual CMFs or in small bundles of CMFs. In the next stage, more CMFs were deposited with these new orientations and the bundles became larger. New orientations arose by a shift towards more longitudinal directions, starting from either the S-helix or the Z-helix form. It was only after an almost longitudinal orientation was reached that the CMFs were deposited in two opposing directions again and a new sheet was formed. Neither colchicine nor cremart influenced the changes in CMF deposition. It is concluded that microtubules do not control CMF deposition in cortical cells of tobacco explants; control of CMF deposition and microtubule orientation occurs by factors related to cell polarity.

Organization of actin filaments in regenerating and outgrowing subprotoplasts from pollen tubes ofNicotiana tabacum L

The dynamics of actin-filament organization in pollen-tube subprotoplasts ofNicotiana tabacum L. cv. Samsun during regeneration and outgrowth was examined using phalloidin probes and a non-fixation method. A succession of actin arrays was examined during subprotoplast regeneration that strongly resembled the actin dynamics described for developing microspores by Van Lammeren et al. (1989, Planta178, 531-539) and activated pollen by Tiwari and Polito (1988, Protoplasma147, 5-15). At the end of the succession the actin filaments often became extended between two opposite polar foci. The ordering of the cortical actin filaments reflected a polarity in the subprotoplasts which determined the plane of outgrowth. The site of outgrowth was often marked by a ring of actin filaments. As growth proceeded and tube-like structures were formed, the arrangement of cortical actin filaments was found to be transverse to the elongation axis. Since the patterns of actin distribution were identical in both caryoplasts and cytoplasts, it was concluded that the pollen-tube cytoplasm has the intrinsic capacity of reorganizing actin filaments and imposing polarity on the spherical subprotoplasts.

Microtubules in root hairs

The microtubules of root hairs of Raphanus sativus, Lepidium sativum, Equisetum hyemale, Limnobium stoloniferum, Ceratopteris thalictroides, Allium sativum and Urtica dioica were investigated using immunofluorescence and electron microscopy. Arrays of cortical microtubules were observed in all hairs. The microtubules in the hairs show net axial orientations, but in Allium and Urtica helical microtubule patterns are also present. Numerical parameters of microtubules in Raphanus, Equisetum and Limnobium were determined from dry-cleave preparations. The results are discussed with respect to cell wall deposition and cell morphogenesis.

Computereinsatz in der praxisbezogenen forensisch-toxikologischen Analytik

For more than 10 years the analytical data gathered on nearly 600 drugs and other potentially poisonous substances that came up in our own investigations, as well as the pertinent bibliography, were stored in card indexes and lists. For immediate and fast recall via terminal we now store this cumulative data collection on magnetic tapes or disks in our clinic host computer. Extensive software was developed in FORTRAN compiler language to achieve rapid coordination of the data measured to that stored and consequently permit positive identification of unknown substances. The data obtained by different analytical methods such as TLC, GC, ultraviolet and infrared spectra, or HPLC can be evaluated by selective or sequential procedures using variable tolerances. That is also possible to enlarge and complete these data files in an easy manner using the same software.

Identification of the heat shock band 2-48B of Drosophila hydei and determination of its haploid DNA content

The heat shock locus 2-48B situated at the tip of the second chromosome of Drosophila hydei has been studied by various cytologic methods. Both from puffing behaviour and in situ hybridization on both wildtype animals and heterozygotes for the mutant chromosome Df(2)e20 the actual site is localized in band 2-48B8. Electron microscopically this band appears to be a medium size, dotted band. From cytophotometric measurements on Feulgen stained chromosomes and electron microscopic observations the DNA content of band 2-48B8 is calculated to be approximately 40 kb on the haploid level, with a compaction of the DNA of about 160 times. The interbands 2-48B7-8 and 2-48B8-9, flanking the heat shock band, were calculated to contain on the haploid level 1.5 kb and 3.0 kb, respectively. The results are discussed also in relation to the present data on the molecular organization of this locus.

The banding pattern of the salivary gland chromosomes of Drosophila hydei

The banding pattern of the salivary gland chromosomes of D. hydei was investigated in the electron microscope. We compared the banding pattern of squashed chromosomes with non-squashed preparations and observed that the fixation and squash procedure we used does not introduce artificial changes in the banding pattern of the chromosome. An electron microscopic map was made of the banding pattern of the distal half of the second salivary gland chromosome. On the basis of the number of bands in this part of the second chromosome we calculated a total of about 3700 bands for the whole set of polytene chromosomes of D. hydei. Our data indicate a similar number of bands in the salivary gland chromosomes of evolutionary remote Drosophila species like D. hydei and D. melanogaster.

The fourth chromosome of Chironomus tentans Malpighian tubules: an ultrastructural study

Morphology and banding pattern of the 4th chromosome in Chironomus tentans Malpighian tubules have been investigated by electron microscopy, using the squash and selection technique. The map we composed from our observations shows a remarkable increase (75%) in band numbers as compared to the map previously presented by Beermann for the 4th chromosome from salivary glands. Extrapolation of this increase to the entire genome would result in a total band number of about 3,500. The mean DNA content of bands can thus be calculated to be about 50 kb. Many bands show a complex structure, including the BR2 band. Some bands seem to result from fusion of smaller components. "Minibands" have also been observed. Some interbands contain RNP particles. In our material the interbands appeared to be made up of fibrils with a diameter of about 120 A. On the basis of these results we estimate the DNA in the interbands as amounting to 2% of the entire genome. The results are discussed with respect to the organization of the polytene chromosomes and the functional significance of the banding pattern.

Identification of the Balbiani ring 2 chromomere and determination of the content and compaction of its DNA

The giänt puff Balbiani ring 2 (BR 2) in the salivary glands of Chironomus tentants is known to contain transcriptionally active 75S RNA genes. The corresponding chromosomal superstructure, the BR 2 chromomere, has been identified and characterized in the present study. It was demonstrated by cytological methods that BR 2 originates from the broad band IV-3B10, since all the bands except the 3B10 band could be detected as intact bands in the vicinity of BR 2. In situ hybridization of BR 2 RNA to squashed Malpighian tubule chromosomes lacking BR 2, showed that all or almost all the DNA sequences complementary to BR 2 RNA are located in the 3B10 band. The DNA amount in the 3B10 band, designated the Br 2 band, was measured in relation to the DNA content of the whole chromosome set by both direct and indirect microspectrophotometry of Feulgen-stained Malpighian tubule chromosomes. From a determination of the haploid DNA content in sperm cells (0.25 pg), the amount of DNA in at BR 2 chromomere could then be calculated to be 5.1 x 10-4 pg DNA or 470 kb DNA. A minimum value of the DNA compaction within the BR 2 chromomere was estimated to 380 from the B-form length of BR 2 DNA (160 mum) and the thickness of the BR 2 band (0.42 mum). Since there are only between 1 and 4 75S RNA genes, 37 kb in size, in a BR 2 chromomere, most of the BR 2 DNA must consist of DNA not coding for 75S RNA. The nature of this DNA is discussed in relation to the high average AT-content of Chironomus DNA. The orgnization of the chromosome fiber in the BR 2 chromomere is considered in relation to the gene activation process in the salivary glands, i.e. the formation of a 75S RNA transcription loop from a protion of the tightly packed chromosome fiber in the BR 2 chromomere.

Cytochemical studies on RNP complexes produced by puff 2-48BC in Drosophila hydei: uranyl acetate and phosphotungstic acid staining

Differential staining of the core and RNP particles of RNP complexes in puff 2--48 BC in salivary gland chromosomes of Drosophila hydei was achieved with aqueous uranyl acetate (UA) at low pH, with UA in acetone, with phosphotungstic acid (PTA) in organic solvents, and with aqueous PTA at pH 5 And 6. A comparison of the results of UA and PTA staining under various conditions indicate that the proteins in the core region and in the RNP particles connected to it differ with respect to their amino-acid composition (arginine and lysine residues).--The staining mechanism of PTA and UA is discussed.

Induced RNP production in different cell types of Drosophila

The typical RNP complexes produced in puff 2-48BC in the salivary gland chromosomes as a consequence of treatments interfering with the cellular respiratory metabolism have been found in various other cell types after treatment with 5-10- minus 2 M vitamin B6 for 4 hr. In Drosophila hydei the typical RNP complexes were present in puff 2-48BC in the nuclei of gastric caeca cells, in nuclei of cells of the imaginal (wing) discs and embryonic cells in primary culture. Similar RNP complexes were observed in a puff in D. virilis salivary gland nuclei, but not in salivary gland nuclei of D. melanogaster.