The molecular phylogenetics of the genus Oligoryzomys (Rodentia: Cricetidae) clarifies rodent host–hantavirus associations

Several species of the genus Oligoryzomys are natural hosts of different hantavirus genotypes affecting humans. The systematics of the genus is confusing, which complicates the identification of the rodent host and hence the potential endemic areas of hantavirus pulmonary syndrome. In this study, we analyse molecular data to infer phylogenetic relationships among Central and South American specimens of Oligoryzomys, and compare our results with previously published data on karyotypic, geographic distribution and host–virus associations to solve contradictory taxonomic reports. We identified 25 clades, each one corresponding to a different putative species. The phylogenetic trees show that Oligoryzomys longicaudatus is strongly related to the Oligoryzomys flavescens complex, which comprises four clades; Oligoryzomys nigripes is related to Oligoryzomys stramineus, Oligoryzomys vegetus is related to Oligoryzomys fulvescens from Central America, and Oligoryzomys brendae is the sister species of Oligoryzomys aff. destructor. We identified the following rodent host–hantavirus genotype relationships: O. longicaudatus–Andes; O. flavescens ‘West'–Bermejo; O. flavescens ‘East'–Lechiguanas; O. nigripes–Juquitiba; Oligoryzomys microtis–Rio Mamore and Rio Mamore‐3; Oligoryzomys chacoensis–Oran; Oligoryzomys costaricencis–Choclo; Oligoryzomys delicatus–Maporal; Oligoryzomys utiaritensis–Castelo dos Sonhos; Oligoryzomys sp. RT2012–Rio Mamore‐4; Oligoryzomys sp. (and not Oligoryzomys fornesi)–Anajatuba. This work, besides contributing to the development of prevention programmes for hantavirus epidemiology in Latin America, represents a comprehensive update of the systematics of the genus Oligoryzomys. © 2014 The Linnean Society of London     

Mutations in the fumarate hydratase gene cause hereditary leiomyomatosis and renal cell cancer in families in North America

Hereditary leiomyomatosis and renal cell cancer (HLRCC) is an autosomal dominant disorder characterized by smooth-muscle tumors of the skin and uterus and/or renal cancer. Although the identification of germline mutations in the fumarate hydratase (FH) gene in European families supports it as the susceptibility gene for HLRCC, its role in families in North America has not been studied. We screened for germline mutations in FH in 35 families with cutaneous leiomyomas. Sequence analysis revealed mutations in FH in 31 families (89%). Twenty different mutations in FH were identified, of which 18 were novel. Of these 20 mutations, 2 were insertions, 5 were small deletions that caused frameshifts leading to premature truncation of the protein, and 13 were missense mutations. Eleven unrelated families shared a common mutation: R190H. Eighty-one individuals (47 women and 34 men) had cutaneous leiomyomas. Ninety-eight percent (46/47) of women with cutaneous leiomyomas also had uterine leiomyomas. Eighty-nine percent (41/46) of women with cutaneous and uterine leiomyomas had a total hysterectomy, 44% at age < or =30 years. We identified 13 individuals in 5 families with unilateral and solitary renal tumors. Seven individuals from four families had papillary type II renal cell carcinoma, and another individual from one of these families had collecting duct carcinoma of the kidney. The present study shows that mutations in FH are associated with HLRCC in North America. HLRCC is associated with clinically significant uterine fibroids and aggressive renal tumors. The present study also expands the histologic spectrum of renal tumors and FH mutations associated with HLRCC.     

Relationship Between Escherichia coli B Titer and the Level of Deoxycytidylate Deaminase Activity Induced on Bacteriophage T2r+ Infection

The activities of six bacteriophage T2r(+)-induced enzymes (thymidylate synthetase, deoxycytidylate deaminase, thymidylate kinase, deoxycytidylate hydroxymethylase, deoxycytidine pyrophosphatase, and dihydrofolate reductase) were measured after dilution of phage-infected Escherichia coli B from 8 x 10(8) to 2 x 10(8) cells per ml. The only enzyme activity altered was that of deoxycytidylate deaminase, which increased three- to fourfold. Conversely, the rapid concentration of cells from 2 x 10(8) to 8 x 10(8) per ml did not result in a reduction in deaminase activity. Although an enhancement in aeration reduced the response of deoxycytidylate deaminase to cellular dilution, the influence of potential metabolic inhibitors or activators could not be shown. The change in deoxycytidylate deaminase activity appeared to be associated with an altered translational event, since the increase could not be prevented by rifampin but was blocked effectively by chloramphenicol and hydroxylamine. In addition, antibody to the T2 phage-induced deoxycytidylate deaminase demonstrated that the increase in enzyme activity was associated with a corresponding increase in radioactive leucine incorporated into the enzyme antigen.     

Ophirasterol, a new C31 sterol from the marine sponge Topsentia ophiraphidites

Analysis of the sterol fraction obtained from the Colombian Caribbean sponge Topsentia ophiraphidites revealed that this sponge is a rich source of C30 and C31 sterols. Among them, a new C31 sterol, named ophirasterol, was isolated, and its structure was established as (22E,24R)-24-(1-buten-2-yl)cholesta-5,22-dien-3beta-ol (1) by spectral means and comparison with synthetic C-24 epimers with known configuration. Other isolated C30 and C31 sterols were the known 24-ethyl-24-methyl-22-dehydrocholesterol (2), 24-isopropyl-22-dehydrocholesterol (3), 24-isopropylcholesterol (4), 24-ethyl-24-methylcholesterol (5), 24-isopropenyl-25-methyl-22-dehydrocholesterol (6) and 24-isopropenyl-25-methylcholesterol (7), and 24-isopropenyl-22-dehydrocholesterol (8).     

Induction of c-fos and c-jun mRNA at the M/G1 border is required for cell cycle progression

The proto-oncogenes c-fos and c-jun have been shown in numerous model systems to be induced within minutes of growth factor stimulation, during the G₀/G₁ transition. In this report we use the mitotic shake-off procedure to generate a population of highly synchronized Swiss 3T3 cells. We show that both of these immediate-early, competence genes are also induced during the M/G₁ transition, immediately after completion of mitosis. While c-fos mRNA levels drop to undetectable levels within 2 hr after division, c-jun mRNA levels are maintained at a basal level which is ～ 30% maximum throughout the remainder of G₁. In order to access the functional significance of these patterns of c-fos and c-jun expression, antisense oligodeoxynucleotides specific to c-fos or c-jun were added to either actively growing Swiss 3T3 cells or mitotically synchronized cells, and their ability to inhibit DNA synthesis and cell division determined. Our results show that treatment of Swiss 3T3 cells with either c-fos or c-jun antisense oligodeoxynucleotides, while actively growing, during mitosis, or in early G₁, results in a reduction in ability to enter S and subsequently divide. This was also true if Swiss 3T3 cells were treated during mid-G₁ with c-jun antisense oligodeoxynucleotides. These results demonstrate that the regulation of G₁ progression following mitosis is dependent upon the expression and function of the immediate-early, competence proto-oncogenes c-fos and c-jun. © 1994 Wiley-Liss, Inc.     

Characterization and risk assessment of the invasive papaya mealybug,Paracoccus marginatus,in Kenya under changing climate

The present study was conducted to characterize the newly invasive papaya mealybug Paracoccus marginatus Williams and Granara de Willink in Kenya using molecular techniques and to establish the potential risk of spread of the pest. Although abundant literature of P. marginatus outbreaks exists in other parts of the world, studies from Africa are rare. Our results revealed significant similarity between Kenyan samples with GenBank accession number KP692333.1 of P. marginatus. Phylogenetic analyses generated a tree that was paraphyletic with two clusters showing low genetic distance values for the P. marginatus sequences, which diverged from that of Planococcus citri. Our models displayed an optimal performance with mean area under the curve value of 0.82 and 0.98 for Genetic Algorithm for Rule-Set Production (GARP) and maximum entropy modelling (MaxEnt), respectively. Isothermality was the most influential variable in determining the potential distribution of P. marginatus with a 69% contribution to the models. Other variables included temperature mean diurnal range temperature seasonality, temperature annual range and annual precipitation in decreasing order of contribution. Current prediction by both models exceeded the existing range of P. marginatus, exacerbating the potential threat of the pest. GARP was more conservative in predicting suitable areas for P. marginatus, while MaxEnt showed further expansion by the year 2050. Our findings provide important information to guide biosecurity agencies in decision-making to prevent the spread and enhance control efforts of P. marginatus.     

Stereotaxic Administration of 1-Methyl-4-Phenylpyridinium Ion (MPP+) Decreases Striatal Fructose 2,6-Bisphosphate in Rats

Abstract: The Stereotaxic administration of 1-methyl-4-phenylpyridinium ion (MPP⁺) into the neostriatum of male rats caused a lesion that resulted in a large dose-dependent loss of striatal fructose 2,6-bisphosphate; initial values were restored 5 days after the treatment. This effect was not protected by systemic administration of MK-801 or by nitroarginine. The content of hexose 6-phosphates and ATP was also reduced by MPP⁺ treatment, whereas lactate was increased. Biochemical and histological results suggested that MPP⁺ caused a nonselective cell death, followed by a pronounced astroglial response, parallel to fructose 2, 6-bisphosphate recovery. The Stereotaxic administration of rotenone showed a different time effect on fructose 2,6-bisphosphate cerebral content, with a significantly faster recovery. These results indicate that cerebral fructose 2,6-bisphosphate may be a sensitive metabolite related to brain damage caused by potent neurotoxins such as MPP⁺. On the other hand, they show that MPP⁺ acts in the brain through a quick, strong cytotoxic mechanism, which probably involves mechanisms other than mitochondria! chain blockage     

Population dynamics of a motile and a non-motile Azospirillum lipoferum strain during rice root colonization and motility variation in the rhizosphere

Abstract: Azospirillum lipoferum 4B and non-motile A. lipoferum 4T have been simultaneously isolated from rice rhizosphere at the same frequency. A. lipoferum 4T showed stable morphological and metabolic traits which are atypical for A. lipoferum species such as lack of motility, carbohydrate metabolism and laccase activity. Inoculation experiments showed that A. lipoferum 4T, but not A. lipoferum 4B, needed rice roots to stabilize in sterile soil. Both strains were able to colonize efficiently rice roots (10⁸ cfu g⁻¹ fresh roots) but motile form 4B remained dominant. In spite of their phenotypical differences, A. lipoferum 4B and 4T co-existed without exclusion in sterile soil (planted or not) and rice rhizosphere. Inoculation of rice roots with A. lipoferum 4B showed that rice rhizosphere enhanced the frequency of appearance of stable non-motile forms (40%). This percentage was weaker in plantlet growth medium (4%). However, these non-motile bacteria kept the same biochemical traits than the motile parental strain 4B (carbohydrates metabolism, laccase activity).