The biotransformation of methyl ent-15-oxokaur-16-en-19-oate by Rhizopus stolonifer and Mucor plumbeus

Incubation of methyl ent-15-oxokaur-16-en-19-oate with Rhizopus stolonifer and Mucor plumbeus gave methyl ent-7β,11-dihydroxy-15-oxokauran-19-oate and methyl ent-7β,16β-dihydroxy-15-oxokauran-19-oate, respectively.     

Calmodulin in rat enterocyte: an immunogold electron-microscope study

Immunogold labeling of ultrathin sections of the epithelium of rat small intestine has been used to obtain insights into the ultrastructural localization and possible function of calmodulin in the enterocyte. Calmodulin is found mainly overlying the periphery of the microvillous core, in agreement with the location of the 110-kDa calmodulin complex. Extremely small amounts of calmodulin can be detected along the interdigitating basolateral membrane. This immunogold electron-microscope study suggests that calmodulin plays an important role in regulating the mechanochemical activity of myosin I but not in processes associated with the basolateral membrane of rat enterocyte.     

Inherited Interleukin-12 Deficiency: IL12B Genotype and Clinical Phenotype of 13 Patients from Six Kindreds

Interleukin-12 (IL12) is a cytokine that is secreted by activated phagocytes and dendritic cells and that induces interferon-gamma production by natural-killer and T lymphocytes. It consists of two subunits, p35 and p40, which are encoded by IL12A and IL12B, respectively. The first reported patient with a genetic cytokine disorder was a Pakistani child, who was homozygous for a large loss-of-function deletion (g.482+82_856-854del) in IL12B. This IL12-deficient child suffered from infections caused by bacille Calmette-Guérin (BCG) and Salmonella enteritidis. We herein report 12 additional patients from five other kindreds. In one kindred from India, the same large deletion that was described elsewhere (g.482+82_856-854del) was identified. In four kindreds from Saudi Arabia, a recessive loss-of-function frameshift insertion (g.315_316insA) was found. A conserved haplotype encompassing the IL12B gene suggested that a founder effect accounted for the recurrence of each mutation. The two founder mutational events-g.482+82_856-854del and g.315_316insA-were estimated to have occurred approximately 700 and approximately 1,100 years ago, respectively. Among a total of 13 patients with IL12 deficiency, 1 child had salmonellosis only and 12 suffered from clinical disease due to BCG or environmental nontuberculous mycobacteria. One patient also had clinical disease caused by virulent Mycobacterium tuberculosis, five patients had clinical disease caused by Salmonella serotypes, and one patient had clinical disease caused by Nocardia asteroides. The clinical outcome varies from case to case, since five patients (aged 2-11 years) died of overwhelming infection, whereas eight patients (aged 3-12 years) are still in good health and are not currently taking antibiotics. In conclusion, IL12 deficiency is not limited to a single kindred, shows significant variability of outcome, and should be considered in the genetic diagnosis of patients with mycobacteriosis and/or salmonellosis. To date, two founder IL12B mutations have been identified, accounting for the recurrence of a large deletion and a small insertion within populations from the Indian subcontinent and from the Arabian Peninsula, respectively.     

Application of Natural Blends of Phytochemicals Derived from the Root Exudates of Arabidopsis to the Soil Reveal That Phenolic-related Compounds Predominantly Modulate the Soil Microbiome

The roots of plants have the ability to influence its surrounding microbiology, the so-called rhizosphere microbiome, through the creation of specific chemical niches in the soil mediated by the release of phytochemicals. Here we report how these phytochemicals could modulate the microbial composition of a soil in the absence of the plant. For this purpose, root exudates of Arabidopsis were collected and fractionated to obtain natural blends of phytochemicals at various relative concentrations that were characterized by GC-MS and applied repeatedly to a soil. Soil bacterial changes were monitored by amplifying and pyrosequencing the 16 S ribosomal small subunit region. Our analyses reveal that one phytochemical can culture different operational taxonomic units (OTUs), mixtures of phytochemicals synergistically culture groups of OTUs, and the same phytochemical can act as a stimulator or deterrent to different groups of OTUs. Furthermore, phenolic-related compounds showed positive correlation with a higher number of unique OTUs compared with other groups of compounds (i.e. sugars, sugar alcohols, and amino acids). For instance, salicylic acid showed positive correlations with species of Corynebacterineae, Pseudonocardineae and Streptomycineae, and GABA correlated with species of Sphingomonas, Methylobacterium, Frankineae, Variovorax, Micromonosporineae, and Skermanella. These results imply that phenolic compounds act as specific substrates or signaling molecules for a large group of microbial species in the soil.     

Immunohistochemistry of the golden hamster pituitary during chronic administration of diethylstilbestrol: a quantitative analysis using confocal laser scanning microscopy

The aim of this study was to examine by immunohistochemistry the morphologic changes affecting pituitary cell populations in male Syrian hamsters undergoing chronic exposure (3 days to 9 months) to diethylstilbestrol (DES). Cell proliferation in the hypophysis was monitored by the immunohistochemical demonstration of S-phase cells after pulse labeling with 5-bromo-2'-deoxyuridine. Cell proliferation analysis was combined with the identification of different cell populations by immunostaining with antisera raised against hypophyseal hormones. Sections processed for double-label immunofluorescence were examined by confocal microscopy. In the adenohypophysis, the relative surface occupied by gonadotrophs and thyrotrophs decreased rapidly during the first months of treatment while corticotroph and somatotroph populations remained unaffected. Accordingly, the incidence of S-phase cells in these four cell populations was lower than or similar to control values. In contrast, lactotrophs increased gradually during the first month of exposure to DES to reach a maximum value at 2-4 months. At the beginning, this increase was primarily due to hyperplasia but later on it also involved cellular hypertrophy. Somatomammotrophs did not seem to be involved in this model. In the pars intermedia, the labeling index of melanotrophs rose rapidly to reach values 5-6 times higher than controls. After 4 months, neoplasms originating from the pars intermedia were seen invading both the neuro- and the adenohypophysis. At the end of treatment, the pituitary was markedly enlarged resulting from the development of an adenoma of the pars intermedia.     

Tobacco plants epigenetically suppressed in phenylalanine ammonia-lyase expression do not develop systemic acquired resistance in response to infection by tobacco mosaic virus

The response of tobacco (Nicotiana tabacum L. cv. Xanthinc) plants, epigenetically suppressed for phenylalanine ammonia-lyase (PAL) activity, was studied following infection by tobacco mosaic virus (TMV). These plants contain a bean PAL2 transgene in the sense orientation, and have reduced endogenous tobacco PAL mRNA and suppressed production of phenylpropanoid products. Lesions induced by TMV infection of PAL-suppressed plants are markedly different in appearance from those induced on control plants that have lost the bean transgene through segregation, with a reduced deposition of phenofics. However, they develop at the same rate as on control tobacco, and pathogenesis-related (PR) proteins are induced normally upon primary infection. The levels of free salicylic acid (SA) produced in primary inoculated leaves of PAL-suppressed plants are approximately fourfold lower than in control plants after 84 h, and a similar reduction is observed in systemic leaves. PR proteins are not induced in systemic leaves of PAL-suppressed plants, and secondary infection with TMV does not result in the restriction of lesion size and number seen in control plants undergoing systemic acquired resistance (SAR). In grafting experiments between wild-type and PAL-suppressed tobacco, the SAR response can be transmitted from a PAL-suppressed root-stock, but SAR is not observed if the scion is PAL-suppressed. This indicates that, even if SA is the systemic signal for establishment of SAR, the amount of pre-existing phenylpropanoid compounds in systemic leaves, or the ability to synthesize further phenylpropanoids in response to the systemic signal, may be important for the establishment of SAR. Treatment of PAL-suppressed plants with dichloro-isonicotinic acid (INA) induces PR protein expression and SAR against subsequent TMV infection. However, treatment with SA, while inducing PR proteins, only partially restores SAR, further suggesting that de novo synthesis of SA, and/or the presence or synthesis of other phenylpropanoids, is required for expression of resistance in systemic leaves.     

EFFECTS OF IRON AND LIGHT STRESS ON THE BIOCHEMICAL COMPOSITION OF ANTARCTIC PHAEOCYSTIS SP. (PRYMNESIOPHYCEAE). II. PIGMENT COMPOSITION

A strain of Phaeocystis sp., isolated in the Southern Ocean, was cultured under iron- and light-limited conditions. The cellular content of chlorophyll a and accessory light-harvesting (LH) pigments increased under low light intensities. Iron limitation resulted in a decrease of all light-harvesting pigments. However, this decrease was greatly compensated for by a decrease in cell volume. Cellular concentrations of the LH pigments were similar for both iron-replete and iron-deplete cells. Concentrations of chlorophyll a were affected only under low light conditions, wherein concentrations were suppressed by iron limitation. Ratios of the LH pigments to chlorophyll a were highest for iron-deplete cells under both light conditions. The photoprotective cycle of diato/diadinoxanthin was activated under high light conditions, and enhanced by iron stress. The ratio of diatoxanthin to diadinoxanthin was highest under high light, low iron conditions.   Iron limitation induced synthesis of 19'-hexanoyloxyfucoxanthin and 19'-butanoyloxyfucoxanthin at the cost of fucoxanthin. Fucoxanthin formed the main carotenoid in iron-replete Phaeocystis cells, whereas for iron-deplete cells 19'-hexanoyloxyfucoxanthin was found to be the main carotenoid. This shift in carotenoid composition is of importance in view of the marker function of both pigments, especially in areas where Phaeocystis sp. and diatoms occur simultaneously. A hypothesis is presented to explain the transformation of fucoxanthin into 19'-hexanoyloxyfucoxanthin and 19'-butanoyloxyfucoxanthin, referring to their roles as a light-harvesting pigment.