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Meiosis is a modified cell division that produces four haploid nuclei from a single diploid cell in two rounds of chromosome segregation. Here, we analyze the role of Arabidopsis thaliana SUPPRESSOR WITH MORPHOGENETIC EFFECTS ON GENITALIA7 (SMG7), THREE DIVISION MUTANT1 (TDM1), and TARDY ASYNCHRONOUS MEIOSIS (TAM) in meiotic progression. SMG7 is a conserved nonsense-mediated mRNA decay factor that is also, in Arabidopsis , essential for completion of meiosis. Examination of activating CYCLIN DEPENDENT KINASE A;1 phosophorylation at Thr-161 suggests that the meiotic arrest observed in smg7 mutants is likely caused by a failure to downregulate cyclin-dependent kinase (CDK) activity at the end of the second meiotic division. Genetic analysis indicates that SMG7 and TDM1 act in the same pathway to facilitate exit from meiosis. We further demonstrate that the cyclin TAM is specifically expressed in meiosis I and has both stimulatory and inhibitory effects on progression to meiosis II. TAM knockouts skip the second meiotic division producing unreduced gametes, but inactivation of SMG7 or TDM1 alleviates TAM's requirement for entry into meiosis II. We propose a model that meiotic progression in Arabidopsis pollen mother cells is driven by a yet to be identified cyclin-CDK activity that is modulated by regulatory interactions between TDM1, SMG7, and TAM. [ABSTRACT FROM AUTHOR]

Earthquake-related groundwater level changes have been recorded by a dense network of monitoring well stations in Taiwan. At most multiple-well stations, the direction and magnitude of coseismic water level changes vary in wells of different depths. Comprehensive water level data recorded in 209 wells in the vicinity of the seismogenic fault during the 1999 ML7.3 earthquake demonstrate a preliminary 3-D distribution of coseismic changes. The largest coseismic rise at a station observed typically in a confined gravel aquifer indicates the association of the magnitude of coseismic change with characteristics, rather than depth, of the aquifer. The variation of coseismic changes in the vertical direction implies possible inconsistency between the observed water level changes and the volumetric strains calculated from simple dislocation models. At a given hypocentral distance, the coseismic change in the footwall of the ruptured segment of the fault was much greater than that of the unruptured segment. This phenomenon suggests that fault displacement plays an important role in the generation of coseismic changes. While hypocentral distance correlates well with coseismic rise or fall in the vicinity of the ruptured seismogenic fault, poor correlation is found for coseismic change further from the earthquake epicentre. [ABSTRACT FROM AUTHOR]

A 16 year old Chinese female with puerperal ovarian vein thrombophlebitis following uneventful vaginal delivery is reported. This infrequent, but potentially fatal, complication in the febrile postpartum patient may present as a surgical emergency. Non-invasive diagnostic procedures and conservative treatment with heparinization and antibiotics have been suggested. However, early exploratory laparotomy for ovarian vein or caval ligation may be life-saving if the diagnosis is in doubt or the response to conservative treatment is unsuccessful. [ABSTRACT FROM PUBLISHER]