Hyphal tip growth in fungi is important because of the economic and medical importance of fungi, and because it may be a useful model for polarized growth in other organisms. We have investigated the central questions of the roles of cytoskeletal elements and of the precise sites of exocytosis and endocytosis at the growing hyphal tip by using the model fungus Aspergillus nidulans. Time-lapse imaging of fluorescent fusion proteins reveals a remarkably dynamic, but highly structured, tip growth apparatus. Live imaging of SYNA, a synaptobrevin homologue, and SECC, an exocyst component, reveals that vesicles accumulate in the Spitzenkö rper (apical body) and fuse with the plasma membrane at the extreme apex of the hypha. SYNA is recycled from the plasma membrane by endocytosis at a collar of endocytic patches, 1-2 m behind the apex of the hypha, that moves forward as the tip grows. Exocytosis and endocytosis are thus spatially coupled. Inhibitor studies, in combination with observations of fluorescent fusion proteins, reveal that actin functions in exocytosis and endocytosis at the tip and in holding the tip growth apparatus together. Microtubules are important for delivering vesicles to the tip area and for holding the tip growth apparatus in position. INTRODUCTIONPolarized cell growth occurs in most eukaryotic phyla, and it includes a plethora of important phenomena, such as neuronal growth cone extension in animals and pollen tube extension in vascular plants. It is particularly important in filamentous fungi where nearly all growth occurs by hyphal tip extension (reviewed by Momany, 2002). Given that some filamentous fungi are important fermentation organisms, the growth of which is of considerable economic importance, whereas others are serious plant, animal, and human pathogens, there is considerable interest in the mechanisms of tip growth in these organisms.A great deal of progress has been made in understanding fungal tip growth (summarized by Harris et al., 2005; Steinberg, 2007a,b;Riquelme et al., 2007), but key questions remain unanswered. There is general agreement that fungal tip growth involves the synthesis of cell wall components in the cell body, the incorporation of these components into vesicles, the transport of these vesicles to the cell tip, the fusion of these vesicles with the plasma membrane in the area of the cell tip (exocytosis) to release their contents, and the cross-linking of the components after release. It is clear that both microtubules and actin microfilaments play important roles in fungal tip growth, but their exact functions are not yet defined. The exact sites of exocytosis and endocytosis also remain to be determined. The positions of the site(s) of exocytosis are particularly important because fungal walls are relatively stiff structures, and once they have formed the shape of the hypha is established. Hyphal shape is thus determined to a very significant extent by where the wall precursors are released from the cytoplasm, i.e., by the positioning of the site(s) of exocyto...

A method to rapidly generate gene replacement constructs by fusion PCR is described for Aspergillus nidulans. The utility of the approach is demonstrated by green fluorescent protein (GFP) tagging of A. nidulans ndc80 to visualize centromeres through the cell cycle. The methodology makes possible large-scale GFP tagging, promoter swapping, and deletion analysis of A. nidulans.

SummaryAlthough age‐related ovarian failure in female mammals cannot be reversed, recent strategies have focused on improving reproductive capacity with age, and rapamycin is one such intervention that has shown a potential for preserving the ovarian follicle pool and preventing premature ovarian failure. However, the application is limited because of its detrimental effects on follicular development and ovulation during long‐term treatment. Herein, we shortened the rapamycin administration to 2 weeks and applied the protocol to both young (8 weeks) and middle‐aged (8 months) mouse models. Results showed disturbances in ovarian function during and shortly after treatment; however, all the treated animals returned to normal fertility 2 months later. Following natural mating, we observed prolongation of ovarian lifespan in both mouse models, with the most prominent effect occurring in mice older than 12 months. The effects of transient rapamycin treatment on ovarian lifespan were reflected in the preservation of primordial follicles, increases in oocyte quality, and improvement in the ovarian microenvironment. These data indicate that short‐term rapamycin treatment exhibits persistent effects on prolonging ovarian lifespan no matter the age at initiation of treatment. In order not to disturb fertility in young adults, investigators should in the future consider applying the protocol later in life so as to delay menopause in women, and at the same time increase ovarian lifespan.

ethyl alcohol ͉ fetal alcohol spectrum disorders ͉ photolabel

No abstract

Falling like dominos: The first direct organocatalytic asymmetric cyclopropanation reaction of oxindole was developed, in which oxindoles were employed as a dinucleophilic C1 synthon and bromonitroolefins with a dielectrophilic center were used as a C2 synthon (see scheme). An amino acid based multifunctional catalyst promoted the [2+1] reaction, giving the products in high yields and excellent enantioselectivities. A divergent synthesis of different stereoisomers of 3‐spirocyclopropyl‐2‐oxindoles was achieved.

f Highly drug-resistant Salmonella enterica serovar Indiana became the most common serovar in broilers with diarrhea in China over the course of this study (15% in 2010 to 70% in 2014). While most S. Indiana isolates (87%, 384/440) were resistant to 13 to 16 of the 16 antibiotics tested, 89% of non-S. Indiana isolates (528/595) were resistant to 0 to 6 antibiotics. Class 1 integrons and IncHI2-type plasmids were detected in all S. Indiana isolates, but only in 39% and 1% of non-S. Indiana isolates.

Phthalides were used for the first time in the allylic alkylation reactions with MBH carbonates for the creation of chiral 3,3-disubstituted phthalides. Highly enantioselective regiodivergent synthesis of γ-selective or β-selective allylic alkylation products was achieved by employing bifunctional chiral phosphines or multifunctional tertiary amine-thioureas as the catalyst, respectively. It was demonstrated that proper selection of catalysts and reaction conditions would differentiate an S(N)2'-S(N)2' pathway and an addition-elimination process, yielding different regioisomers of the allylic alkylation products in a highly enantiomerically pure form.