bluuebunny/crossref_metadata_2025 huggingface dataset:
Early Infant Human Immunodeficiency Virus Type 1 Detection Suitable for Resource-Limited Settings with Multiple Circulating Subtypes by Use of Nested Three-Monoplex DNA PCR and Dried Blood Spots
Authors: Zhang Qi , Wang Linhong , Jiang Yan , Fang Liwen , Pan Pinliang , Gong Shuangyan , Yao Jun , Tang Yi-Wei , Vermund Sten H. , Jia Yujiang
Published: December 2007

The early detection of human immunodeficiency virus type 1 (HIV-1) infection in infants is complicated by the persistence of maternal antibodies and by diverse HIV-1 subtypes. We developed a nested, three-monoplex HIV-1 DNA PCR (N3M-PCR) assay to detect diverse HIV-1 subtypes in infants born to infected mothers. We optimized the test for use with dried blood spot (DBS) samples for ease of storage and transport from rural China to central laboratories. Six pairs of primers were designed that targeted
env, gag
, and
pol
genes, and the test was run in three reactions with an analytical sensitivity of 10 copies DNA per reaction to cover nine HIV-1 subtypes, A, B, C, D, F, G, CRF01-AE, CRF08-BC, and CRF07-BC. The assay performance was evaluated on 347 DBS specimens from 151 exposed infants in four diverse provinces of China in which multiple subtypes were circulating. The results of this test were compared to those of HIV antibody enzyme immunoassay and Western blotting confirmation for the infants at ≥18 months of age or to convincing clinical and epidemiologic data for deceased infants. The sensitivity of the N3M-PCR assay was 30.0% (3/10) for infants at 48 h after birth, 91.7% (11/12) at 1 to 2 months of age, and 93.7% (15/16) at 3 to 6 months of age. The specificity was 100% (94/94) at all three time points. The PCR reproducibility in the three DNA regions was 100% for samples at 48 h after birth, 96.7% at 1 to 2 months, and 100% at 3 to 6 months of age. The HIV-1 DNA N3M-PCR assay on DBSs offers a simple and affordable approach for early infant HIV-1 diagnosis in regions with diverse HIV-1 circulating subtypes.
Development of Multiplex Assay for Rapid Characterization ofMycobacterium tuberculosis
Authors: Bergval I. L. , Vijzelaar R. N. C. P. , Dalla Costa E. R. , Schuitema A. R. J. , Oskam L. , Kritski A. L. , Klatser P. R. , Anthony R. M.
Published: December 2007

We have developed a multiplex assay, based on multiplex ligation-dependent probe amplification (MLPA), that allows simultaneous detection of multiple drug resistance mutations and genotype-specific mutations at any location in theMycobacterium tuberculosisgenome. The assay was validated on a reference panel of well-characterized strains, and the results show thatM. tuberculosiscan be accurately characterized by our assay. Eighteen discriminatory markers identifying drug resistance (rpoB,katG,inhA,embB), members of theM. tuberculosiscomplex (16S rRNA, IS6110, TbD1), the principal genotypic group (katG,gyrA), and Haarlem and Beijing strains (ogt,mutT2,mutT4) were targeted. A sequence specificity of 100% was reached for 16 of the 18 selected genetic targets. In addition, a panel of 47 clinicalM. tuberculosisisolates was tested by MLPA in order to determine the correlation between phenotypic drug resistance and MLPA and between spoligotyping and MLPA. Again, all mutations present in these isolates that were targeted by the 16 functional probes were identified. Resistance-associated mutations were detected by MLPA in 71% of the identified rifampin-resistant strains and in 80% of the phenotypically isoniazid-resistant strains. Furthermore, there was a perfect correlation between MLPA results and spoligotypes. When MLPA is used on confirmedM. tuberculosisclinical specimens, it can be a useful and informative instrument to aid in the detection of drug resistance, especially in laboratories where drug susceptibility testing is not common practice and where the rates of multidrug-resistant and extensively drug resistant tuberculosis are high. The flexibility and specificity of MLPA, along with the ability to simultaneously genotype and detect drug resistance mutations, make MLPA a promising tool for pathogen characterization.
Analysis of Echovirus 30 Isolates from Russia and New Independent States Revealing Frequent Recombination and Reemergence of Ancient Lineages
Authors: Lukashev Alexander N. , Ivanova Olga E. , Eremeeva Tatiana P. , Gmyl Larisa V.
Published: December 2007

We studied two genome regions, VP1 and 3D, of 48 echovirus 30 (E30) isolates from Russia and the new independent states. In VP1, most isolates were similar to European strains reported earlier, and frequent change of circulating subgroups was noticed. We also observed, in 2003-2006, the reemergence of a group of E30 strains with a VP1 region very distant from most modern E30 strains and remotely similar to E30 isolates from the 1960s and the 1970s. A study of the 3D genome region detected multiple recombination events among the studied strains. Recombination presumably occurred every few years, and therefore, the study of a single VP1 genome region cannot accurately describe the phylogenetic history of the virus or predict pathogenetic properties of an isolate. In general, a comparison of the VP1 and 3D genome region phylogenies revealed, in some instances, virtually independent circulation of enterovirus genome fragments on a scale of years.
Heat Shock Perturbs TRIM5α Restriction of Human Immunodeficiency Virus Type 1
Authors: Anderson Jenny L. , Campbell Edward M. , Figueiredo Anna , Hope Thomas J.
Published: December 2007

TRIM5α restriction factors protect target cells from retroviruses by blocking infection prior to the accumulation of viral reverse transcription (RT) products. Here, we demonstrate that heat shock perturbed owl monkey TRIMCyp and rhesus TRIM5α-mediated restriction of human immunodeficiency virus type 1 (HIV-1) late RT products and 2-long terminal repeat circles. Heat shock partially rescued HIV-1 infection from TRIMCyp restriction, and this rescue became more profound when combined with the presence of the proteasome inhibitor MG132. This indicates that viral RT products rescued from restriction by either heat shock treatment or the presence of MG132 are on a productive pathway, supporting a model in which TRIM5α proteins restrict retroviruses in multiple phases that are differentially sensitive to heat shock and proteasome inhibitors.
Intracellular Localization Map of Human Herpesvirus 8 Proteins
Authors: Sander Gaby , Konrad Andreas , Thurau Mathias , Wies Effi , Leubert Rene , Kremmer Elisabeth , Dinkel Holger , Schulz Thomas , Neipel Frank , Stürzl Michael
Published: December 2007

Human herpesvirus 8 (HHV-8) is the etiological agent of Kaposi's sarcoma. We present a localization map of 85 HHV-8-encoded proteins in mammalian cells. Viral open reading frames were cloned with a Myc tag in expression plasmids, confirmed by full-length sequencing, and expressed in HeLa cells. Protein localizations were analyzed by immunofluorescence microscopy. Fifty-one percent of all proteins were localized in the cytoplasm, 22% were in the nucleus, and 27% were found in both compartments. Surprisingly, we detected viral FLIP (v-FLIP) in the nucleus and in the cytoplasm, whereas cellular FLIPs are generally localized exclusively in the cytoplasm. This suggested that v-FLIP may exert additional or alternative functions compared to cellular FLIPs. In addition, it has been shown recently that the K10 protein can bind to at least 15 different HHV-8 proteins. We noticed that K10 and only five of its 15 putative binding factors were localized in the nucleus when the proteins were expressed in HeLa cells individually. Interestingly, in coexpression experiments K10 colocalized with 87% (13 of 15) of its putative binding partners. Colocalization was induced by translocation of either K10 alone or both proteins. These results indicate active intracellular translocation processes in virus-infected cells. Specifically in this framework, the localization map may provide a useful reference to further elucidate the function of HHV-8-encoded genes in human diseases.
The Picornavirus Avian Encephalomyelitis Virus Possesses a Hepatitis C Virus-Like Internal Ribosome Entry Site Element
Authors: Bakhshesh Mehran , Groppelli Elisabetta , Willcocks Margaret M. , Royall Elizabeth , Belsham Graham J. , Roberts Lisa O.
Published: December 2007

Avian encephalomyelitis virus (AEV) is a picornavirus that causes disease in poultry worldwide, and flocks must be vaccinated for protection. AEV is currently classified within the hepatovirus genus, since its proteins are most closely related to those of hepatitis A virus (HAV). We now provide evidence that the 494-nucleotide-long 5′ untranslated region of the AEV genome contains an internal ribosome entry site (IRES) element that functions efficiently in vitro and in mammalian cells. Unlike the HAV IRES, the AEV IRES is relatively short and functions in the presence of cleaved eIF4G and it is also resistant to an inhibitor of eIF4A. These properties are reminiscent of the recently discovered class of IRES elements within certain other picornaviruses, such as porcine teschovirus 1 (PTV-1). Like the PTV-1 IRES, the AEV IRES shows significant similarity to the hepatitis C virus (HCV) IRES in sequence, function, and predicted secondary structure. Furthermore, mutational analysis of the predicted pseudoknot structure at the 3′ end of the AEV IRES lends support to the secondary structure we present. AEV is therefore another example of a picornavirus harboring an HCV-like IRES element within its genome, and thus, its classification within the hepatovirus genus may need to be reassessed in light of these findings.
Rescue of Maturation-Defective Flock House Virus Infectivity with Noninfectious, Mature, Viruslike Particles
Authors: Walukiewicz Hanna E. , Banerjee Manidipa , Schneemann Anette , Johnson John E.
Published: December 2007

The infectivity of flock house virus (FHV) requires autocatalytic maturation cleavage of the capsid protein at residue 363, liberating the C-terminal 44-residue γ peptides, which remain associated with the particle. In vitro studies previously demonstrated that the amphipathic, helical portion (amino acids 364 to 385) of γ is membrane active, suggesting a role for γ in RNA membrane translocation during infection. Here we show that the infectivity of a maturation-defective mutant of FHV can be restored by viruslike particles that lack the genome but undergo maturation cleavage. We propose that the colocalization of the two defective particle types in an entry compartment allows the restoration of infectivity by γ.
Synthesis of Methoxy Substituted Centrally Chiral Triynes as Precursors of Functionalised Nonracemic Helicene-Like Compounds
Authors: Krausová Zuzana , Sehnal Petr , Teplý Filip , Stará Irena G. , Starý Ivo , Šaman David , Cvačka Josef , Fiedler Pavel
Published: December 2007

A modular synthesis of a series of methoxy substituted optically pure aromatic triynes (-)-(S)-5-9 and (-)-(R)-10 is presented. It relies on key operations such as substitution of benzylic bromine with an alkoxy group and aryl-alkyne coupling reaction to combine appropriate methoxy substituted benzene/naphthalene building blocks and chiral alkynol synthons such as (-)-(2S)-but-3-yn-2-ol and (-)-(1R)-1-phenylprop-2-yn-1-ol. The triyne molecules comprise a diphenylacetylene, 1-(phenylethynyl)naphthalene or 1,1'-ethyne-1,2-diyldinaphthalene core unit. They are intended to serve as [2+2+2] cyclisation precursors of methoxy substituted nonracemic helicene-like compounds with a penta-, hexa- and heptacyclic helical scaffold.
Synthetic Utility of 1-Hydroxycarbazole-2-carbaldehydes - Syntheses of Furo-, Oxazino- and Pyranocarbazoles
Authors: Martin Arputharaj E. , Rajendra Prasad Karnam J.
Published: December 2007

Reaction of 1-hydroxycarbazole-2-carbaldehydes 1 with phenacyl bromide yielded 2-benzoyl-10H-furo[2,3-a]carbazoles 2, whereas the reaction with ethyl bromoacetate yielded 1-oxo-1,2-dihydro[1,4]oxazino[2,3,4-jk]carbazole-4-carbaldehyde (4). The reaction of 1 with ethyl acetoacetate and also with diethyl malonate yielded the pyranocarbazoles 6 and 7, respectively. All the products were characterized by spectral and analytical means. Plausible mechanisms of product formation are proposed.
Integration of human papillomavirus type-16 and type-18 is a very early event in cervical carcinogenesis
Authors: Huang L-W , Chao S-L , Lee B-H
Published: December 2007

Aim:

Human papillomavirus (HPV) integration is a critical event in cervical carcinogenesis. The aim of this study was to explore the physical status of HPV-16 and HPV-18 during the progression of cervical precancerous lesions.

Methods:

A series of 101 HPV-16 or HPV-18 positive cervical neoplasms (32 cervical intraepithelial neoplasia (CIN) cases and 69 cervical carcinoma (CC) cases) were evaluated. The physical status of both types of HPV was assessed from paraffin-embedded formaldehyde-fixed surgical specimens by real-time PCR.

Results:

For HPV-16, integrated DNA was observed in 5 (83.3%) of 6 CIN I cases, 10 (90.9%) of 11 CIN II/III cases, 29 (82.9%) of 35 FIGO (International Federation of Gynecology and Obstetrics) stage I CC cases and 16 (94.1%) of 17 FIGO stages II∼IV CC cases. For HPV-18, integrated DNA was observed in 3 (50%) of 6 CIN I cases, 5 (55.6%) of 9 CIN II/III cases, 9 (64.3%) of 14 FIGO stage I CC cases, and 1 (33.3%) of 3 FIGO stages II∼IV CC cases. The mixed form of HPV DNA was the most prevalent physical state in HPV-16. There was no significant difference between the physical state of HPV-16 and HPV-18 DNA with regard to the various grades of cervical lesions.

Conclusions:

These data imply that integration of HPV-16 and HPV-18 DNA into the host genome occurs in the very early stage of cervical neoplastic progression. These early events may play an initiating role in the malignant transformation of HPV-16- and HPV-18-related low-grade lesions into high-grade dysplasia and invasive carcinoma.
Omeprazole-associated changes in the gastric mucosa of children
Authors: Drut R , Altamirano E , Rúa E Cueto
Published: December 2007

Aims:

To describe histological findings in gastric mucosa biopsy specimens of children treated with proton-pump inhibitors (PPIs) for different periods of time.

Methods:

Biopsy specimens from 12 children (aged 8 months to 15 years) treated with PPIs and 8 controls were processed for paraffin embedding and stained with H&E as well as inmmunohistochemically for sialyl-Tn antigen.

Results:

The main changes were related to parietal cells which showed brisk cytoplasmic eosinophilia, apical cytoplasmic protrusions to dilated glands, cytoplasmic and nuclear hypertrophy, dilated intracytoplasmic canaliculi, binucleation and multinucleation. The intracellular canaliculi surface showed strong immunohistochemical reaction for sialyl-Tn antigen, apparently a marker for this structure. Some of the patients were biopsied after a short period of oral or intravenously administered omeprazole; the changes may therefore occur rapidly.

Conclusions:

PPIs induce the same changes in the gastric mucosa of children as in adults, but the number of nuclei is increased. These effects have not been reported previously in this age group. It is suggested that the changes result from a combination of effects of PPIs and gastrin release.
Studies on the release of sugar into the vessels of sugar maple (Acer saccharum)
Authors: Sauter Jörg J. , Iten Werner , Zimmermann Martin H.
Published: December 2007

The release of sucrose into the vessel water of sugar maple (Acer saccharum Marsh.) has been investigated with biochemical and enzyme-cytochemical methods. The amount of sucrose released into the vessels in isolated stem segments was found to be temperature-dependent. The release of sucrose also proved to be inhibited when p-chloromercuribenzoate as an inhibitor of respiratory enzymes was present in the vessels. This suggests that the sucrose release is dependent upon the respiratory activity of some cells. In the cytochemical studies much increased activity of respiratory enzymes (succinate, NAD-dependent isocitrate, and alcohol dehydrogenases) and of acid phosphatases could be demonstrated in the contact cells of the ray and axial parenchyma. Phosphatase activity was concentrated on the large pits between contact cells and vessels. These increased enzyme activities in contact cells were restricted to the time when sucrose appeared in the vessels. Since contact cells are the only cells of the ray and axial parenchyma that show peculiar pit connections with the vessels and also show increased respiratory and phosphatase activity, these cells are considered to be the specific sites of a metabolically controlled sucrose release.
Apparent recovery from the field of hyaline-spored strains of Bipolaris sorokiniana 15 years after their introduction
Authors: Harding Howard
Published: December 2007

Isolates of Bipolaris sorokiniana with hyaline conidia were obtained from subcrown internodes of single plants of four Triticum species grown on land which, 15 years previously, had been planted with seed inoculated with two hyaline-spored strains. All isolates were pathogenic and produced a "toxin" in culture. Three distinct colony types were distinguished and representatives of both mating types, "A" and "a," appeared to be present. The new isolates were compared with isolate K3 which was one of the isolates used in 1956. Isolate K3 was equally pathogenic but produced no "toxin" in culture. On autoclaved straw, conidia of the new isolates were somewhat shorter than those of K3 but were otherwise similar. On minimal medium all the new isolates produced abundant small, subspherical conidia with one to two pseudosepta. Germ tubes were produced from one or both terminal cells.
Nitrate reductase activity of dark-grown and light-exposed etiolated field peas (Pisum arvense)
Authors: Jones R. W. , Sheard R. W.
Published: December 2007

The nitrate reductase of etiolated field peas (Pisum arvense L. cv. Century) is described. Enzyme activity is maximally extracted into a cysteine-free solution. Absolute enzyme activities, in dark-grown plants and in plants exposed for a short period to 600 μW∙cm−2 of white light, and the extent of induction by light, were high in the terminal buds and declined rapidly in the basal direction along the shoot. Soluble protein distribution followed nitrate reductase activity in opposite direction to the acropetal decrease in nitrate concentration. Nitrate reductase in dark-grown terminal buds showed adaptation to the supply of nutrient nitrate concentration, and 2 h of white light also elicited an enzyme response that depended on nitrate. The effect of light is demonstrated to be largely independent of photosynthetic light utilization since 5 min of white light, followed by 115 min of darkness, led to activity increases that were about 80% of increases after 2 h of white light. Enzymologically, the nitrate reductase of dark-grown terminal buds appeared to be identical with the light-induced enzyme and also with the enzyme of green plant tissues as characterized in the literature.
A survey of stomatal movements and associated potassium fluxes in the plant kingdom
Authors: Willmer C. M. , Pallas Jr. J. E.
Published: December 2007

Histochemical tests for K+ were carried out on the epidermis of aerial organs from plants which varied in evolutionary development (e.g., clubmosses, ferns, angiosperms) and general morphology (e.g., monocotyledons, succulent dicotyledons, woody dicotyledons). These tests made on epidermal tissue with open or closed stomata suggested that K+ transport is implicated in stomatal movements regardless of the evolutionary level and the stomatal location in the plants investigated. In all species that displayed substantial stomatal opening, K+ was detectable in the guard cells. With small stomatal apertures, K+ was located in guard and subsidiary cells of Commelina communis L. leaves and Glycine max. L. cotyledons. When stomata were closed, K+ was detectable in the subsidiary cells of all the grass species, Kalanchoë pinnata Pers., C. communis, and, occasionally, in the epidermal cells surrounding the stomata of some ferns. A condition was also observed when virtually no K+ was detectable in the guard or subsidiary cells of C. communis leaves or G. max cotyledons. Commonly, when stomata were closed, K+ was not detectable in any cells of the epidermis. Exceptions were the "K+ storage cells," trichomes and epidermal cells of Arachis hypogaea L., and in the more primitive plants from and including the level of the ferns.
Fungi from decomposing Spartina alterniflora
Authors: Gessner Robert V. , Goos R. D.
Published: December 2007

Spartina alterniflora, the dominant plant species of the tidal salt marshes on the east coast of the United States, contributes significantly to estuarine primary productivity. Energy stored by the plant is released through decomposition as detritus or decomposer biomass. The role of fungi in these transformations has not been elucidated and was investigated in the present study. Dried, dead grass was confined in nylon bags, exposed on a salt marsh and in an adjacent tidal creek in southern Rhode Island, and a quantitative and qualitative study made of the fungi found to be associated with the decomposing grass. Twenty-seven species of fungi were isolated. The average number of fungal colonies/g dry wt. of grass was found to be higher in material exposed on the salt marsh and subjected to immersion only at high tide (2436) than from material immersed in an adjacent creek (1021). The grass lost about 50% dry wt. after 6 months of exposure on the marsh.
Some physiological responses of Verticillium albo-atrum to zinc
Authors: Throneberry G. O.
Published: December 2007

Zinc markedly stimulated growth of Verticillium albo-atrum R. & B. in Czapek-Dox broth shake cultures. Minimum zinc concentration producing optimum growth response was 0.15 to 0.2 μg/ml. On a dry weight basis added zinc resulted in increased total nitrogen content and oxygen uptake. Oxygen uptake per unit total nitrogen was essentially unaffected. Cells from 5- and particularly 7-day-old zinc-free cultures showed less response to zinc than did those from 3- and 10-day-old cultures. Zinc response was greatest with L-alanine as the nitrogen source as compared with nitrate, urea, and ammonium nitrate sources.
Two new species of Balladyna from East Africa
Authors: Eboh Dan O. , Cain R. F.
Published: December 2007

Two new species of Balladyna Raciborski are described: B. magna sp. nov. on Paramacrolobium coeruleum (Taub.) J. Leonard in Kenya, and B. tarennae sp. nov. found on Tarenna pavettoides (Harv.) Sim. in Tanzania.
Observations on the morphology, reproduction, and fine structure of Chlamydomonas segnis from Delta Marsh, Manitoba
Authors: Badour S. S. , Tan C. K. , Caeseele L. A. Van , Isaac P. K.
Published: December 2007

Variations in the morphology of Chlamydomonas segnis have been investigated under various cultural conditions. In cultures maintained at 250 ft-c and 15 °C without aeration, this alga assumed the form of a Gloeocystis, whereas in aerated mass-culture grown at 25–30 °C and 1000 ft-c the motile stage showed close similarity to the genus Gloeomonas. Cells of C. segnis growing in synchronous culture under high light intensity (1000 ft-c) and supplied with 5% CO2 in air (v/v) reproduced asexually to form four zoospores, whereas cells provided with air produced only two zoospores. When zoospores developed in light their increase in cell volume was not accompanied by an increase in the length of their flagella. Homothallic anisogamous sexual reproduction could be demonstrated under conditions unfavourable for growth. Ultrathin sections of cells developed in light revealed a lobate, cup-shaped chromatophore. The mitochondria possessed irregular profiles with constrictions and were mainly located on the outer surface of the chloroplast. Intracytoplasmic, convoluted inclusions and interthylakoidal crystals have been observed. Microbody-like organelles, similar to those in plant leaf tissue, occurred in autotrophically grown C. segnis.
Localization of β-glycerophosphatase activity in the myxomycete Perichaena vermicularis
Authors: Cronshaw James , Charvat Iris
Published: December 2007

The myxomycete Perichaena vermicularis has been fixed with formaldehyde–glutaraldehyde at various stages of fruiting and the distribution of β-glycerophosphatase determined at the electron microscope level using a modified Gomori procedure. Specimens from various stages of the developing fruiting body when incubated for 70–105 min at 39 °C in a medium containing β-glycerophosphate showed good localization of reaction product. High β-glycerophosphatase activity was localized in single-membrane-bound vacuoles at all stages of fruiting body formation. These vacuoles are similar to lysosomes of animals, higher plants, and fungi in that they are surrounded by a single membrane, contain cell components at various stages of disintegration, and have a high acid phosphatase activity.Reaction product was also localized in the walls of mature spores and was variably associated with nuclei and mitochondria. Most probably the staining of some nuclei and mitochondria is a lead absorption artifact.
Aspects of metabolic development in an illuminated synchronous culture of Scenedesmus obtusiusculus
Authors: Das Gaurangakumar
Published: December 2007

Developing synchronous cells of Scenedesmus obtusiusculus Chod. were investigated during the 15-h light period of the 24-h life cycle. Measurements were made of photosynthesis and of the chlorophyll, carotene, nucleic acid, and protein content, including intracellular phosphorus.Photosynthetic oxygen evolution (μmol/mg chlorophyll) increased during the early growing stage and declined gradually in the older cells. Chlorophyll, carotene, protein, ribonucleic acid, and ribonucleic acid phosphate of these cells increased during the growth phase (dry weight basis) and declined in the sporulating phase, whereas the deoxyribonucleic acid and deoxyribonucleic phosphate decreased during the growth phase. Deoxyribonucleic acid increased slightly in the sporulating phase, but deoxyribonucleic acid phosphate remained relatively constant during this period. When calculated on a per cell basis, ribonucleic acid and ribonucleic acid phosphate increased steadily throughout the period of observation, whereas deoxyribonucleic acid and deoxyribonucleic acid phosphate remained constant during the first 5 h and then increased gradually. Analysis of the intracellular distribution of phosphorus(dry weight basis) revealed that methanol-soluble (lipid) phosphorus decreased steadily with cell growth, whereas the content of acid-soluble phosphorus and ethanol–ether-soluble (lipid) phosphorus fluctuated markedly. The pH of the culture medium increased concomitantly with cellular development during the light period.
Influence of calcium on the metabolism of chlorophyll, carotene, nucleic acid, and protein in Scenedesmus
Authors: Das Gaurangakumar
Published: December 2007

The influence of calcium supply on the chlorophyll, carotene, nucleic acid, and protein content in Scenedesmus obtusiusculus Chod. was investigated. Evidence showed that upon addition of calcium-starved cells to a culture medium containing calcium, the levels of all these components increased slowly for 15 h. During the next 33 h chlorophyll and carotene content increased more rapidly, and the chlorophyll a:b ratio also increased. During this growth period, both RNA and protein content increased linearly whereas DNA content did not increase on a dry weight basis throughout the period of observation.
Ascocarp development in Mycoarctiutn ciliatum
Authors: Jain K. , Morgan-Jones J. F.
Published: December 2007

Mycoarctium ciliatum, a coprophilic discomycete, was isolated from deer dung and grown on nutrient medium. Single ascospore cultures form ascocarps within 2 weeks. Typically, apothecial formation is associated with two to six well-developed ascogonia; ontogeny of the ascogonium is discussed. Excipulum and paraphyses both originate from the basal cells of the ascogonium and appear before the ascogenous system. The ascogonium also produces septate ascogenous hyphae of two types, primary and secondary. Asci form directly from ascogenous hyphal tips or via croziers, and may or may not be delimited by a septum from the subtending element. Conjugate division in ascogenous hyphae is implied by the presence of nuclear quartets. There is some evidence that asci may occasionally arise from paraphyses.
New Hyphomycetes from South Carolina
Authors: Pirozynski K. A. , Hodges Jr. C. S.
Published: December 2007

Some interesting Hyphomycetes collected on fallen leaves of Persea borbonia (L.) Spreng. in South Carolina include Chaetochalara aspera sp. nov., Circinotrichum fertile sp. nov. and its hyperparasite Scolecobasidium dendroides sp. nov., Menisporopsis profusa sp. nov., Redbia elegans sp. nov., Uberispora simplex (Ichinoe) gen. & comb. nov. (≡ Arachnophora simplex Ichinoe), and Thozetella cristata sp. nov.The genus Thozetella O. Kuntze is broadened further to include T. tocklaiensis (Agnihothrudu) comb.nov. (≡ Thozetellopsis tocklaiensis Agnih.) and T. radicata (Morris) comb. nov. (≡ Neottiosporella radicata Morris).
A quantitative study and multivariate analysis of corticolous lichen communities in the southern boreal forest of Saskatchewan
Authors: Jesberger J. A. , Sheard J. W.
Published: December 2007

Quantitative data on the occurrence of corticolous lichens in 40 forest stands involving a total of 8000 randomly selected quadrats have been gathered and subjected to both ordination by principal-components analysis and agglomerative classification in an attempt to define community relations. The results of these two methods of analysis are in agreement and indicate that variation between communities is essentially discontinuous and related to the host substrate. Effects of a more continuous nature related to moisture levels and age of the trees within each stand are also strongly suggested by the ordinations. The distribution of the different growth forms is related to environmental variables and discussed.
Developmental studies on leafy spurge (Euphorbia esula). Histochemical and autoradiographic studies of the adventitious shoot apices
Authors: Raju M. V. S. , Ho Teresa W. M.
Published: December 2007

Analysis of apices at four different developmental stages (progressively older from I to IV) of adventitious shoots of leafy spurge (Euphorbia esula L.) was carried out. In this study, some selected histochemical and autoradiographic techniques were used to study DNA, histone, and RNA changes during vegetative shoot growth. In the early vegetative phases (stages I to III), the DNA distribution and DNA synthesis based on Feulgen stain and thymidine-H3 incorporation respectively were found to be greater in the peripheral sectors (S1 and S3) than in the midsector (S2) and consequently the apex showed a characteristic cytozonation. The central zone (S2) showed less DNA staining and the rate of DNA synthesis was slower than that in the peripheral sectors. This central zone, which is often considered as méristème d'attente, cannot be interpreted similarly for there was slow DNA synthesis as indicated by the low incorporation of thymidine-H3. It is suggested that the nuclei in S2 in stages II and III had a longer mitotic cycle than those in S1 and S3. The zonal pattern seen in the early stages disappeared in stage IV. This final stage may be considered as the "intermediate phase" during the transformation of the vegetative apex to the floral apex. The distribution of nucleohistones based on results of alkaline fast-green staining procedure was similar to that of Feulgen stain for DNA at all four stages. However, when lysine groups in the histone were blocked by acetylation method, the apices showed that the arginine-rich histone fraction was dominant and uniform in all four stages. This means that in stages II and III, S2 had less lysine-rich histone fraction than S1 and S3. The nuclei in S2 in stages II and III had longer mitotic cycle and this was probably due to less lysine-rich histone content. The cytoplasmic RNA observed by following pyronin Y – methyl green staining method and RNA synthesis based on uridine-H3 incorporation showed no sharp differences among the three sectors of the apex in all four developmental stages. It is interpreted, therefore, that the central zone (S2) in the apex was, although slow, quite active metabolically during the development of the adventitious shoot.
Photoperiodic adaptation in Xanthium strumarium populations introduced to Australia
Authors: McMillan Calvin
Published: December 2007

Seedlings derived from field-collected burs from Australia were tested for photoperiodic adaptation and morphologies. Four morphophysiological types were represented from northern Victoria to southern Queensland. The widespread chinense morphological complex (Noogoora Burr) has a critical dark period of 10.5 h. The italicum morphological complex of eastern central New South Wales has a critical dark period of 10 h. The cavanillesii morphological complex near Sydney has an apparent critical night of 9.5 h and the pensylvanicum morphological complex in northwestern Victoria has an apparent critical night of 9.25–9.5 h. Two populations in the area of sympatry of the chinense and italicum complexes showed diverse photoperiodic adaptation, ripeness-to-flower (maturity) responses and morphologies, suggesting hybridization. Although Xanthium populations have been in Australia for over 100 years, their morphophysiology matches populations in America with relatively narrow distribution.
Comparative embryology of Stipa elmeri (Gramineae)
Authors: Maze Jack , Bohm Lesley R.
Published: December 2007

The ovule of Stipa elmeri is bitegmetic, hemianatropous, and pseudocrassinucellate. The micropyle is formed by the inner integument. The inner integument is two cells thick except at the micropyle. Its inner layer is persistent and safraninophilic, and some of its cells develop secondary walls. A cuticle is also present outside the inner integument. The outer integument is two cells thick except for a bump four or five cells thick at the chalazal end. At later stages of development, the outer integument breaks down except at the chalazal end. As the ovule develops, it undergoes changes in orientation as a result of growth pattern changes in the nucellus. A multiple protoderm is present in some parts of the nucellus.The outer layer of the nucellus persists to later stages of development and is covered by a cuticle. Fruit wall changes during development are (1) formation of a thick, unlignified wall on the protoderm, (2) elongation of cells lining the locule, and (3) decrease in number of cells. Megagametophyte development is normal and the antipodals proliferate. Before fertilization, both synergids undergo cytological change and one decreases in size. The pollen tube appears to enter at the base of the larger synergid. The endosperm is free nuclear at first but then becomes cellular. At later stages of development, the outer layer of the endosperm is meristematic. On the basis of embryological data, the following phenetic series can be constructed: S. elmeri → S. lemmonii – S. hendersonii → S. tortilis → Oryzopsis miliacea. Available embryological data does not indicate a close relationship between the Gramineae and the Juncaceae or Cyperaceae.
Phytogeography and ecology of the lichen family Parmeliaceae in southwestern Alberta
Authors: Bird C. D. , Marsh A. H.
Published: December 2007

Forty-eight species and two varieties of the genera Cetraria, Hypogymnia, Parmelia, Parmeliopsis, and Platismatia in the lichen family Parmeliaceae are reported from a 13 400-km2 area in the mountains and foothills of southwestern Alberta. Twelve of these taxa are new to Alberta. The distribution and habitats occupied by each of the taxa are described. Thirty-four (67%) of the taxa are of Circumpolar distribution and 17 (33%) are endemic to North America. The three best represented distribution elements are Circumpolar, Arctic – Boreal Alpine – Montane (13 taxa, 26%); Circumpolar, Boreal Montane (9 taxa, 18%); and American, Cordilleran (12 taxa, 24%). One new combination, Hypogymnia enteromorpha var. inactiva, is proposed.
Sampling of Nicotiana tabacum leaf lamina to surmount the problem of nonuniform distribution of total alkaloids
Authors: Rosa Nestor
Published: December 2007

Nonuniform distribution of total alkaloids in leaf lamina of Nicotiana tabacum requires precise positioning of the fixed diameter cutter in obtaining leaf disks which provide a reliable estimate of total alkaloids content of the leaf. This is time-consuming. Other methods such as the whole leaf technique yield excessive amounts of tissue to process. Our procedure uses a band technique that overcomes the problems associated with the unequal distribution of total alkaloids in the lamina and increases sampling rate threefold. This procedure is superior to others for sampling the different sizes of leaves on the plant at anyone time until maturity.
Normal and teratological pistillate spikes of Typha angustifolia (Typhaceae): gross aspects of morphology, anatomy, symmetry, and inflorescence dehiscence
Authors: Wilder George J.
Published: December 2007

Normal and teratological pistillate spikes of Typha angustifolia were found at the same locality in Ohio, U.S.A., and the individual spikes exhibited radial, dorsiventral, and mirror-image symmetry, as well as polarity. Dorsiventral symmetry provided a frame of reference for comparing normal and teratological individuals. Both kinds of pistillate spikes were interpreted to have dorsal and ventral surfaces, sagittal and frontal planes, right and left sides, length, width, and height. Present in teratological spikes, but absent from normal ones, were either split(s) within the central stem axis or exceptionally long type-1 furrow(s). Split(s) or type-1 furrow(s) divided a teratological spike longitudinally into two to five subunits. Where two subunits were present, division was solely along the sagittal plane, whereas spikes with three to five subunits were divided along the sagittal plane and along, or parallel to, the frontal plane. In the case of teratological spikes with two to four subunits it was possible to number and compare subunits in a consistent manner. On some teratological spikes after splitting, subunits had become bowed, rotated, and curled or folded. Apparently, in teratological spikes, indentations and type-1 and type-2 furrows along the sagittal plane function, collectively, as a line of dehiscence. Key words: Typha, morphology, anatomy, symmetry, inflorescence, dehiscence.
Duration of the juvenile period in diffuse knapweed (Centaurea diffusa)
Authors: Thompson D. J. , Stout D. G.
Published: December 2007

In three controlled-environment experiments, diffuse knapweed plants were vernalized at leaf numbers ranging from 1 to 20. Five weeks after return to 16 h light: 8 h dark cycle at 25:20 °C (light:dark), bolting (elongation of flower stalks) was recorded. In a separate field experiment we marked 200 rosettes with leaf numbers ranging from 4 to 26 in November, and on June 30 we recorded which of these had bolted. Probit analysis was used to derive an LN50 (leaf number at which 50% bolting is expected) for each trial. Vernalizing conditions strongly affected the LN50 values derived, mainly through their influence on leaf development. The lowest value of LN50 (5.9 leaves) was obtained with vernalization at 7 °C and 460 μmol m−2 s−1 light intensity, an intermediate value (LN50 = 8.9 leaves) with vernalization at 8 °C and 164 μmol m−2 s−1 intensity, and the highest value (LN50 = 12.6 leaves) with vernalization at 4 °C and 164 μmol m−2 s−1. These experimental conditions allowed an average of 6.5, 4.2, and 1.7 leaves to form during vernalization, respectively. Presumably the vernalizing treatment that allowed the least leaf formation (lowest temperature and light intensity) gave the most reliable estimate of the end of the juvenile period, ending at the formation of the 13th leaf (LN50 = 12.6). Key words: knapweed, vernalization, juvenility, leaf number, bolting.
Endophytic fungi of red alder (Alnus rubra) leaves and twigs in British Columbia
Authors: Sieber T. N. , Sieber-Canavesi F. , Dorworth C. E.
Published: December 2007

A study was designed to isolate potentially pathogenic, endophytic fungi of red alder (Alnus rubra). Apparently healthy leaves and 2- to 3-year-old twigs were collected at three and eight sites, respectively, surface sterilized, cut into small pieces, and incubated on 2% malt extract agar. Ninety percent of the leaves and more than 80% of the twigs were colonized by endophytic fungi; 40 different fungi were isolated and identified. Fungi previously recorded as plant pathogens dominated the endophyte community of leaves (Gnomonia setacea, Gnomoniella tubaeformis, and Septoria alni) but were only minor components of the fungal population of twigs (Melanconis alni and a Nectria species). Abundance of each fungus species and the species composition depended on the plant organ sampled and collection site. In twigs, three main types of endophyte associations occurred among sites: the first was dominated by the unidentified "Black Mycelium 2," the second by Phomopsis sp. 2, and the third by Ophiovalsa suffusa, Pezicula livida, and Phloeosporella sp. The endophyte community of leaves was dominated by G. setacea except at one site where G. tubaeformis was the predominant fungus. Key words: endophytic fungi, fungal community, Alnus rubra, mycoherbicide.
The ecology of Paecilomyces farinosus in two balsam fir forests infested with spruce budworm
Authors: Harney Sharon , Widden Paul
Published: December 2007

The occurrence of Paecilomyces farinosus and other microfungi on litter was monitored in two balsam fir forests infested with spruce budworm to determine the possible role of this fungus as a saprophyte in these forests. The microfungi on the fir litter were similar to those found on other conifers. Paecilomyces farinosus, however, was very abundant, and its abundance increased on the litter after it fell to the ground. An apparent correlation between the abundance of the fungus and the population of spruce budworm suggests that opportunistic parasitism may positively affect the abundance of P. farinosus. Key words: Paecilomyces farinosus, entomopathogens, balsam fir, litter, microfungi.
Effects of light and temperature on germination of heteromorphic achenes of Bidens odorata (Asteraceae)
Authors: Corkidi Lea , Rincon Emmanuel , Vazquez-Yanes Carlos
Published: December 2007

Bidens odorata Cav. (Asteraceae) is an annual weed with heteromorphic achenes that differ in size, weight, and shape within each capitulum. To investigate if the variability of the achene size was correlated with differences in the germination response, achenes were classified in three categories based on size (4, 5–6, and 7 mm), and laboratory experiments were conducted with freshly harvested and dry-stored seeds under several light and temperature conditions. For all conditions tested with fresh seeds, 7-mm achenes germinated faster and with a higher final germination percentage than 4-mm achenes. Germination was inhibited by darkness and far-red light conditions. Experiments conducted with different times of exposure to white light (1 min, 10 min, and 12 h) showed that 4-mm achenes required longer time of exposure to light to maximize their percent germination. However, 7-mm achenes reached similar total percent germination without regard to the period of illumination. Dry storage increased the percent germination significantly in the shorter achenes and altered the light requirement for germination differentially among the morphs. The results suggest a physiological basis of achene heteromorphism that might be related to colonization of different microenvironments. Key words: Bidens odorata, germination, heteromorphism, light, temperature.
The development and zoospore ultrastructure of a polycentric chytridiomycete gut fungus, Orpinomyces joyonii comb.nov.
Authors: Li Jinliang , Heath I. Brent , Cheng K.-J.
Published: December 2007

Orpinomyces bovis, a polycentric gut fungus isolated from a steer, was examined with both light and electron microscopy and renamed Orpinomyces joyonii comb.nov. on the basis of its general morphology and zoospore ultrastructure. The multinucleate rhizomycelium is extensively branched, and sporangia form exogenously on branched or unbranched sporangiophores. The organelles in the zoospores have a distribution pattern typical of other gut fungi, i.e., anterior ribosomal aggregates, central nuclei, and posterior presumptive hydrogenosomes. The perikinetosomal apparatus in O. joyonii is comparable to that in monocentric gut fungi but with minor variations. New details of the posterior dome are described. It contains highly ordered specialized lamellae, peripheral granules, and megatubules. Microtubules intersect the dome predominantly at approximately right angles to its surface; this differs from monocentric gut fungi, in which microtubules form a posterior fan running parallel to the dome. We suggest that both monocentric and polycentric gut fungi are monophyletic, since both have a similar, distinctive perikinetosomal apparatus, posterior dome, and organelle distribution pattern. Key words: Orpinomyces joyonii, gut fungi, ultrastructure, posterior dome, perikinetosomal apparatus.
Clonal architecture of Salix setchelliana (gravel bar willow) in Alaska
Authors: Douglas D. A.
Published: December 2007

Clones of Salix setchelliana were excavated to describe the architecture of this prostrate clonal species and to determine if there are architectural parameters or clonal growth forms that vary with clonal age. The species' gravel-bar habitat, a mosaic of previous river channels, is unpredictable in time and variable in space. Clones are composed of vertical shoots connected by horizontal roots. Because clones expand by peripheral growth of their root systems, the six studied clones could be placed in order of apparent increasing age, primarily on the basis of size. Substrate was removed by hand and the horizontal root systems mapped. Data on shoots, root branch angles, and root peripheral growing points were recorded. Several density parameters were calculated and examined for trends along the sequence of apparent increasing clonal age. Most measures of shoot density increased along this sequence, as did horizontal root system density and the linear density of horizontal root system branching points. Clones appear to change in time from a "guerrilla" growth form of environmental exploration to more of a "battalion" growth form with increased branching of the underground system. Key words: willow, clonal, architecture, Alaska, Salix.
Vascular system of the fertile spikelet of Sorghum (Gramineae: Panicoideae)
Authors: Pizzolato Thompson Demetrio
Published: December 2007

The vascular system of the sessile, fertile spikelet of Sorghum was reconstructed from serial transverse sections. The vascular system is a composite of the basipetal extensions of the traces from the appendages on the rachilla. The rachilla immediately above the glumes consists of an outer and an inner series of these vascular extensions. The basipetal continuations of the median traces of the sterile and fertile lemmas, and of the traces from the stamens comprise the inner series. The outer series consists of the continuations of the many lodicule traces and of vascular bundles descending from the posterior of the pistil. The component of the vascular system related to the pistil is a plexus of xylem and phloem in the form of a hollow cylinder traversed by a large vascular bundle that is the basipetal continuation of the stylar bundles. Bundles from the anterior of the pistil merge with the hollow cylinder at its anterior. Several collateral bundles from the placenta merge with the hollow cylinder at its posterior. Distal portions of these placental bundles supply the short chalaza of the ovule but do not enter it. The vascular system of the fertile spikelet of Sorghum is typical of the Panicoideae, and is useful in distinguishing the Panicoideae from the other subfamilies of grasses. Key words: Sorghum, spikelet, floret, vascular system.