Flavin excretion from roots of iron-deficient sugar beet (Beta vulgaris L.)

The characteristics of flavin excretion from iron-deficient sugar-beet roots have been studied. Roots from iron-deficient sugar beet excreted flavins when plants were allowed to decrease the pH of the nutrient solution, but not when plants were grown in nutrient solutions buffered at high pH. As shown by reversed-phase high-performance liquid chromatography, the two major flavins whose excretion was induced by iron deficiency were different from riboflavin, FMN and FAD. These flavins have been identified as riboflavin 3′-sulfate and riboflavin 5′-sulfate by electrospray-mass spectrometry, inductively coupled plasma emission spectroscopy, infrared spectrometry and¹H-nuclear magnetic resonance. We have characterized the time courses of accumulation of the different flavins in the nutrient solution and considered several possible roles for flavin excretion in iron acquisition.     

Le syndrome de Klinefelter chez l'enfant

Klinfelter syndrome was first described in adult males with gynecomastia, azoospermia and hypergonadotropic hypogonadism. Children with the 47, XXY karyotype demonstrate few clinical findings so Klinefelter syndrome is rarely diagnosed until adult life. Besides children who have been diagnosed during prenatal genetic testing, in infancy a male with 47, XXY (or variants: 46, XY-47, XXY; 48, XXXY; 48, XXYY, 49, XXXXY) may be found while undergoing evaluation of micropenis, hypospadias, cryptorchidism or facial anomalies. The older child may present with learning disabilities, behavior disorders or tall stature. At the time of puberty, the clinical picture includes small testes, gynecomastia and an eunuchoid habitus. Early diagnosis of Klinefelter syndrome must be performed since it has been demonstrated that early treatment with androgens may ameliorate many aspects of the clinical symptoms and attenuate or prevent behavioral and psychiatric disorders associated with 47, XXY males.     

Techniques and high resolution DNA size markers for pulsed field gel electrophoresis

High resolution DNA size markers are described for pulsed field gel electrophoresis (PFGE). These markers provide resolution of 10–20 kbp over a size range from 10 kbp to more than 400 kbp and are produced by partial restriction digestion of lambda phage DNA concatemers (λ ladder). High resolution markers extending to over 400 kbp are made by partial restriction digestion of λ ladder embedded in agarose. Detailed methods are described for marker production and for DNA separation by contour-clamped homogeneous electric field (CHEF) electrophoresis. These markers and methods are useful for a variety of high resolution DNA mapping by PFGE.     

Indications d’une étude méiotique dans l’infertilité masculine

Meiotic investigation is rare in male infertility. Now, some mutations affecting spermatogenesis exhibit characteristic cytogenetic figures, whereas testicular histology does not show specific aspects of this pathology. In male infertility with abnormal somatic caryotype, the aim of meiotic survey is to find the mechanisms inducing spermatogenic failure, and thus to lead to a better understanding of normal spermatogenesis. In addition to cytogenetic techniques, meiosis is also investigated by electron microscopy and molecular biology. Also, we think that a larger place must be grant to meiotic study in male infertility evaluation when the indication of testicular histopathology was settled.     

Urinary excretion of microelements in endurance-trained volunteers during restriction of muscular activity and chronic rehydration

The objective of this investigation was to determine the effect of daily intake of fluid and salt supplementation (FSS) on increased urinary losses of microelements that developed during hypokinesia (decreased number of walking steps/d). The studies were performed on 30 endurance-trained male volunteers aged 23–26 yr, with an averaged maximum oxygen uptake of 65 mL/kg/min during 364 d of hypokinesia (HK). All volunteers were divided into three equal groups: Ten volunteers were placed continuously under an average of 10,000 running steps/d (14.2 km/d) (control subjects), ten volunteers subjected continuously to HK without the use of FSS (hypokinetic subjects), and ten volunteers were continuously submitted to HK and consumed daily FSS (hyperhydrated subjects). For the simulation of the hypokinetic effect the hypokinetic and hyperhydrated volunteers were kept under an average of 3,000 walking steps/d (2.7 km/d) for 364 d. Prior to their exposure to HK the volunteers were on an average of 10,000 running steps/d (14.2 km/d). During the prehypokinetic period of 60 d and during the hypokinetic period of 364 d were determined renal excretion of microelements responses of endurance-trained volunteers. In the hyperhydrated volunteers urinary excretion of iron, zinc, copper, manganese, cobalt, nickel, lead, tin, chromium, aluminum, molybdenum, and vanadium decreased, whereas in the hypokinetic volunteers it increased significantly. It was concluded that chronic hyperhydration may be used to attenuate urinary excretion of microelements in endurance-trained volunteers during prolonged restriction of muscular activity.     

Techniques de détection du VIH dans les milieux biologiques: Application à la recherche du virus dans le sperme

Growing numbers of HIV seronegative women want to have children with HIV infected partners by artificial insemination. The most sensitive assays for showing the presence of the virus are the coculture method and the DNA-PCR that are able to detect proviral load. HIV is detected from non spermatozoal mononuclear cells, seminal fluid but it was not found in spermatozoa fraction. But we know, by in vitro studies, that HIV can bound to and enter spermatozoa. Thus artificial insemination between HIV seropositive man and seronegative woman lead to a risk of contamination even with purified spermatozoa. Today, any virological assay is able to affirm that specimen is not infectious.     

Effects of inorganic arsenicals on DNA synthesis in unsensitized human blood lymphocytes in vitro

Effects of inorganic arsenicals on DNA synthesis in unsensitized human blood lymphocytes were biphasic: The chemicals at very low concentrations enhanced DNA synthesis, whereas higher concentrations inhibited DNA synthesis. The concentrations of arsenicals at which the maximum stimulating effect was found were 1×10^?5 M, 1×10^?6 or 2×10^?6 M, and 0.8×10^?6 or 1×10^?6 M for sodium arsenite exposure of 1 h, 3 d, and 6 d, respectively; for sodium arsenate, 1× 10^?5 M, 1×10^?5 M, and 2×10^?6 or 5×10^?6 M, respectively. Arsenicals must be present for the entire 6-d culture period to produce maximum stimulation of DNA synthesis in human lymphocytes. The longer exposure of the lymphocytes to arsenicals, the lower the concentrations of arsenicals at which the maximum stimulating effect on DNA synthesis was found. Stimulating effect of trivalent arsenic (sodium arsenite) on DNA synthesis was stronger than pentavalent arsenic (sodium arsenate), and the stronger the effect of trivalent arsenic than pentavalent, the longer exposure of the cells to the chemicals. Both sodium arsenite and sodium arsenate stimulated DNA synthesis in human lymphocytes to a lower degree than phytohemagglutinin (PHA).     

RAPD reactions from crude plant DNA

As opposed to standard polymerase chain reaction (PCR) using specific primers, genome analysis involving short random primers, for example RAPD, may yield inconsistent results if crude plant DNA preparations are used as the template. When RNase A, a thermostable enzyme, was added to such reactions, highly repeatable banding patterns were obtained from crude plant DNA, thus speeding up analyses substantially.     

Altered GABAergic and glutamatergic transmission in audiogenic seizure-susceptible mice

The C57BL/10 SPS/sps mouse mutant are audiogenic seizure-susceptible. The enzymatic activities of glutamate decarboxylase (GAD), GABA aminotransferase (GABA-T), alanine aminotransferase (ALA-T), aspartate aminotransferase (ASP-T), and glutamate dehydrogenase (GDH) of whole brain supernatant are significantly reduced in these epileptic mice. GABA uptake is decreased in cortex, midbrain, and pons medulla. Previous studies showed the presence of two sodium-dependent GLU uptake systems in normal (SPS/SPS) mice. Glutamate U_max by System 1 is significantly decreased in these mice, whereas the U_max value for System 2 is significantly increased in the epileptic mice.     

Characterization of mitochondrial DNA topoisomerase I fromNeurospora crassa

DNA topoisomeraseI isolated from the lower eukaryoteNeurospora crassa mitochondria was characterized. Molar mass of the enzyme in the native state is 120 kDa and 60–65 kDa when denatured. The pH optimum of the enzyme is 7.8 and the KCl optimum concentration is 40 mmol/L. This topoisomerase is independent of ATP and Mg²⁺. N-Ethylmaleimide, 4-chloromercuribenzoate, SDS, guanidinium chloride, polyethylene glycol, heparin and ethidium bromide inhibit its activity, while novobiocin, nalidixic acid, Triton X-100 and chloroquine do not. Polyamines, and histone, H1 stimulate the topoisomerase activity. We classify this DNA topoisomerase as typeI and eukaryotic. Conversion of the topoisomerase to a nonspecific endonuclease at increased temperature is proposed.     

Testicule et sperme dans le Syndrome de Klinefelter chez l'adulte

Klinefelter's syndrome is characterised by azoospermia, gynecomastia and hypogonadotropic hypogonadism. The testes are reduced in volume. Microscopically, seminiferous tubules show a reduced diameter and a thickening of peritubular sheath. The seminiferous epithelium contains Sertoli cells with a clear typical nucleus and a heterogeneous nucleolus. Usually there are no germ cells. When present they degenerate at the spermatocyte stage. Very few achieve a complete maturation until the spermatozoon form. The interstitial gland appears relatively hypertrophied, due to the decrease in volume in the other components of the testis. Sometimes Leydig cells display an adenomatous morphology. Therefore the steroidogenic function is impaired. Azoospermia is a major event in Klinefelter's syndrome but sometimes restricted to severe oligozoospermia. In that cases, fertility may be somewhat preserved, and the caryotype usually reveals a mosaicism, 47,XY/47,XXY with a better prognosis than in pure syndrome.     

Plant radioresistance and DNA repair efficiency inChlamydomonas reinhardtii andPisum sativum

This paper compares the repair of DNA single strand breaks (ssb) induced by γ-radiation in two strains ofChlamydomonas reinhardtii (137C/+/ and UVS-I) and three lines ofPisum sativum (NN 131, 198, 140) differing in the degree of radioresistance. DNA ssb in cells exposed to γ-rays (50, 100, 200, 500 Gy) were measured by electrophoresis and alkaline unwinding method with subsequent chromatography on hydroxyapatite immediately after irradiation and after 30 min of post-irradiation incubation at 25°C. An increase of double-strand DNA (in%) was found in cells after 30 min post-irradiation incubation.C. reinhardtii strains displayed an equal level of DNA degradation and repair efficiency in the DNA single strand breaks. The radioresistant line N 198 ofP. sativum is characterized by a lower level of induced DNA ssb and higher efficiency of repair of these breaks as compared with less radioresistant lines NN 131 and 140.     

Diversity in two candidate malaria vaccine antigens in different Indian strains ofPlasmodium falciparum

Polymorphism in two malarial antigens, merozoite surface antigen-1 (MSA-1) and ring erythrocyte surface antigen (RESA), has been characterized in four different Indian strains ofPlasmodium falciparum. The Indian strains were obtained from two malaria endemic regions of India, viz. Surat (Gujarat) and Delhi, and established in culture. Monoclonal and polyclonal antibodies raised against different domains of these antigens were used in the study. In MSA-1 a novel intragenic crossover was detected in the central conserved domain in two of the Indian strains. The repeat domain of RESA was found to be absent in the two strains ofP. falciparum isolated from Surat. These differences in immunoreactivity have been extended to the DNA level by appropriate PCR studies. MSA-1 and RESA are candidate vaccine antigens and these diversities will have an important bearing on the design of a suitable malaria vaccine.     

Alteration of spermatozoal structure and trace metal profile of testis and epididymis of rat under chronic low-level X-ray irradiation

This study investigates the short-term as well as long-term effects of low-level X-ray irradiation on the Spermatozoal structure and trace metal (Zn, Fe, Cu, and Cd) contents in the testis and epididymis of whole-body irradiated albino rats. Male rats were exposed to 0.675, 1.350, 2.700, and 4.050 cGy of X-ray intermittently in 45, 90 180, and 270 equal fractions (each fraction of 0.015 cGy s^?1), respectively. SEM study had revealed numerous fusiform swelling in sperm tail in most of the x-irradiated groups. Moreover, in 2.700 and 4.050 cGy dose groups, the tail sheath of several sperm were eroded out. In the TEM study, damage in microtubules of sperm tail in 4.050 cGy irradiated group was noted. The AAS study showed a transient increase in Zn content in 0.675 and 1.350 cGy dose groups, but its concentration was decreased in 2.700 and 4.050 cGy dose groups. Fe concentration was increased in all the cases in comparison to that of control group. Nevertheless, Cu and Cd contents were increased mostly in 2.700 and 4.050 cGy doses. Thus present findings probably throw some light regarding mammalian response threshold at low-level X-ray irradiation. Moreover, it raises questions regarding the validity of “safe dose ionizing radiation.”     

Yeast artificial chromosome cloning

Yeast artificial chromosome (YAC) cloning systems enable the cloning of DNA stretches of 50 to well over 2000 kb. This makes it possible to study large intact regions of DNA in detail, by restriction mapping the YAC to produce a physical map and by examining the YAC for coding sequences or genes. YACs are important for their ability to clone the complete sequences of large genes or gene complexes that exceed the size limit for cloning in conventional bacterial cloning vectors like plasmids (up to 10 kb), bacteriophage (15 kb), and cosmids (50 kb). A major advantage of cloning in yeast, a eukaryotc. is that many sequences that are unstable, underrepresented, or absent when cloned into prokaryotic systems, remain stable and intact in YAC clones. It is possible to reinlroduce YACs intact into mammalian cells where the introduced mammalian genes are expressed and used to study the functions of genes in the context of flanking sequences. The correct prolein processing mechanisms are present in the mammalian cells to ensure that a viable protein product is produced.     

Cryptorchidie et cancer du testicule

A history of cryptorchidism is the only risk factor for testicular cancer that can be considered unequivocally established. The rate of cryptorchidism at age 3 months appears to have increased over the 30 years from 1.7% to 3.2%. From a review of the literature, the overall proportion of testicular cancer patients with a history of cryptorchidism is approximately 10%. Case-control studies indicate that the relative risks of testicular cancer associated with a history of cryptorchidism are about 6. Prevalence of testicular cancer in patients with a history of cryptorchidism could range between 2% and 3%, as reported in studies from North European Countries. Orchidopexy itself or age at orchidopexy seem to have no effect on the subsequent risk of testicular cancer; however, data from the literature are somewhat discrepant. But orchidopexy does seem to influence the histologic type of malignancy, with a lower frequency of seminoma. The developement of non invasive techniques is badly needed to allow population screening for testicular cancer.     

Hormone-like product of vascular tissue stimulating starch accumulation in pith explants of kale and endogenous cytokinins

When stem explants of kale (Brassica oleracea L. var.medullosa), containing pith parenchyma and a strip of vascular tissue, were cultured on simple sucrose medium, a hormone-like factor was transported from the vascular tissue to the adjacent pith, where it stimulated accumulation of starch. Similarly, up to a sevenfold increase of starch content in explants could be induced by cytokinins added to the culture medium. The relative stimulatory effect of several cytokinins (5×10^?6 M) and hormone-like product of vascular tissue (HPVT) in a typical experiment were: control (1.0), trans-zeatin (6.7), HPVT (6.2), N⁶-[2-isopentenyl]adenine (5.4), transzeatin riboside (5.2), N⁶-[2-isopentenyl]adenosine (5.4), kinetin (3.6), 6-benzylaminopurine (3.5), and adenine (2.1). Concentration of endogenous cytokinins was determined using ELISA (trans-zeatin, N⁶-[2-isopentenyl]adenine and their ribosides) andAmaranthus bioassay (total cytokinins). No effect of vascular tissue on the level of endogenous cytokinins in explants was found. The results support the conclusions of previous experiments that the HPVT stimulating starch accumulation is not a cytokinin.     

Anomalies des autosomes et infertilité masculine

Spermatogenesis impairment is frequently associated with autosomal rearrangements. A meiotic study was performed on testicular biopsies of men ascertained through primary fertility and found to be heterozygous for reciprocal translocation, Robertsonian translocations, inversions and extra chromosomes. Pairing failure at meiosis as well as intimate associations between rearranged autosomes and the XY bivalent have been discussed as a cause of gametogenic arrest.     

In vitro selection and characterization of a callus line ofVigna radiata resistant to NaCl,KCl and Na2SO4

A salt mixture resistant (SMR) cell line ofVigna radiata (L.) Wilczek was isolated by selection on agar solidified PC-L2 medium supplemented with NaCl, KCl and Na₂SO₄ (8∶1∶1) equimolar to 300 mol m^?3 NaCl, a concentration inhibitory to the wild-type non-selected cells (salt mixture sensitive, SMS). This line retained its resistance after subculture for 3 passages (3 months) on normal medium. The SMR line grew significantly better than SMS line at all the levels of salts, though less in saline medium than the SMR on normal medium. The growth of SMR line was significantly higher than that of SMS line under KCl stress. However, both the lines responded similarly to Na₂SO₄ at a concentration higher than 100 mol m^?3. The SMR line was found to be more sensitive to NaCl than SMS line. The SMR line under salt mixture stress maintained lower levels of Na⁺ and higher levels of K⁺ than SMS line. The SMR line failed to regenerate shoots, although rhizogenesis was observed on PC-L2 medium containing salt mixture (300 mol m^?3).     

The role of seed coats in seed viability

The seed coat is the seed’s primary defense against adverse environmental conditions. A hard seed coat protects the seed not only from mechanical stress but also from microorganism invasion and from temperature and humidity fluctuations during storage. Phenolic compounds in the seed coat contribute to seed hardness and inhibition of microorganism growth. During germination, the seed coat protects the seed from hydration stress and electrolyte leakage.