Coronin plays a major role in the organization and dynamics of actin in yeast. To investigate the role of coronin in a filamentous fungus (Neurospora crassa), we examined its subcellular localization ...using fluorescent proteins and the phenotypic consequences of coronin gene (crn-1) deletion in hyphal morphogenesis, Spitzenkörper behavior and endocytosis. Coronin-GFP was localized in patches, forming a subapical collar near the hyphal apex; significantly, it was absent from the apex. The subapical patches of coronin colocalized with fimbrin, Arp2/3 complex, and actin, altogether comprising the endocytic collar. Deletion of crn-1 resulted in reduced hyphal growth rates, distorted hyphal morphology, uneven wall thickness, and delayed establishment of polarity during germination; it also affected growth directionality and increased branching. The Spitzenkörper of Δcrn-1 mutant was unstable; it appeared and disappeared intermittently giving rise to periods of hyphoid-like and isotropic growth respectively. Uptake of FM4-64 in Δcrn-1 mutant indicated a partial disruption in endocytosis. These observations underscore coronin as an important component of F-actin remodeling in N. crassa. Although coronin is not essential in this fungus, its deletion influenced negatively the operation of the actin cytoskeleton involved in the orderly deployment of the apical growth apparatus, thus preventing normal hyphal growth and morphogenesis.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Begomovirus ssDNA plant virus (family Geminiviridae) replication within the Bemisia tabaci vector is controversial. Transovarial transmission, alteration to whitefly biology, or detection of viral ...transcripts in the vector are proposed as indirect evidence of replication of tomato yellow leaf curl virus (TYLCV). Recently, contrasting direct evidence has been reported regarding the capacity of TYLCV to replicate within individuals of B. tabaci based on quantitave PCR approaches. Time-course experiments to quantify complementary and virion sense viral nucleic acid accumulation within B. tabaci using a recently implemented two step qPCR procedure revealed that viral DNA quantities did not increase for time points up to 96 hours after acquisition of the virus. Our findings do not support a recent report claiming TYLCV replication in individuals of B. tabaci.
Circular single-stranded DNA (ssDNA) viruses are the smallest viruses known to infect eukaryotes. High recombination and mutation rates have conferred these viruses with an evolutionary potential ...that has facilitated their emergence. Their damaging effects on livestock (circoviruses) and crops (geminiviruses and nanoviruses), and the ubiquity of anelloviruses in human populations and other mammalian species, have resulted in increased interest in better understanding their epidemiology and infection mechanisms. Circular ssDNA viral replication involves the synthesis of dsDNA intermediates containing complementary-sense (CS) and virion-sense (VS) strands. Precise quantification of VS and CS accumulation during viral infections can provide insights into the molecular mechanisms underlying viral replication and the host invasion process. Although qPCR protocols for quantifying viral molecules exist, none of them discriminate VS and CS strands. Here, using a two-step qPCR protocol we have quantified VS and CS molecule accumulation during the infection process of Tomato yellow leaf curl virus (TYLCV) and Tomato yellow leaf curl Sardinia virus (TYLCSV) (genus Begomovirus, family Geminiviridae). Our results show that the VS/CS strand ratio and overall dsDNA amounts vary throughout the infection process. Moreover, we show that these values depend on the virus-host combination, and that most CS strands are present as double-stranded molecules.
It is broadly accepted that CO is a reliable tracer of H2 in massive IR (L
IR
≳ 10
9
L
⊙
) galaxies, and that there are clear correlations between L
IR
and L’
CO
that are qualitatively independent of ...environment and even redshift. We present two tales on the search for
12
CO emission from dusty star-forming galaxies in both field (Lockman Hole, z < 0.1) and cluster (Zw Cl0024.1+1652, z ∼ 0.4) environments, according to the capabilities of the EMIR receiver at the IRAM-30m telescope. The observed galaxies are part of two follow-up programs in the millimetre regime of the spectroscopic Lockman-SpReSO and GLACE surveys in the optical (OSIRIS / 10.4m GTC). From these data we derived L
IR
and L’
CO
estimations and put them in the framework of the historic records according to the literature for each environmental case. We provide insights about some practical limits of the current facilities (IRAM observatories, ALMA, LMT) to get reliable estimations for IR at low and intermediate redshifts. Our results suggest that the amount of cold gas and the star formation efficiency increase with the cluster-centric distance, hence pointing to an environmental dependency.
The microtubule (MT) "plus end" constitutes the platform for the accumulation of a structurally and functionally diverse group of proteins, collectively called "MT plus-end tracking proteins" ...(+TIPs). +TIPs control MT dynamics and link MTs to diverse sub-cellular structures. Neurospora crassaMicroTubule Binding protein-3 (MTB-3) is the homolog of yeast EB1, a highly conserved +TIP. To address the function of MTB-3, we examined strains with mtb-3 deletions, and we tagged MTB-3 with GFP to assess its dynamic behavior. MTB-3-GFP was present as comet-like structures distributed more or less homogeneously within the hyphal cytoplasm, and moving mainly towards the apex at speeds up to 4× faster than the normal hyphal elongation rates. MTB-3-GFP comets were present in all developmental stages, but were most abundant in mature hyphae. MTB-3-GFP comets were observed moving in anterograde and retrograde direction along the hypha. Retrograde movement was also observed as originating from the apical dome. The integrity of the microtubular cytoskeleton affects the presence and dynamics of MTB-3-GFP comets, while actin does not seem to play a role. The size of MTB-3-GFP comets is affected by the absence of dynactin and conventional kinesin. We detected no obvious morphological phenotypes in Δmtb-3 mutants but there were fewer MTs in Δmtb-3, MTs were less bundled and less organized. Compared to WT, both MT polymerization and depolymerization rates were significantly decreased in Δmtb-3. In summary, the lack of MTB-3 affects overall growth and morphological phenotypes of N. crassa only slightly, but deletion of mtb-3 has strong effect on MT dynamics.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The separation of a mixture of C5–C9 n-paraffins was achieved by Inverse Gas Chromatography (IGC) by using boehmite; AlO(OH), in a packed column with short exposure times and temperatures; from 45 °C ...to 52 °C. The boehmite was characterized by XRD; ATG; SEM; IR spectroscopy and N2 adsorption. The material exhibited a low crystalline boehmite (AlOOH) structure and presented high hydration (pseudoboehmite). The reverse gas chromatography measurements showed that the elution temperatures of the C5–C9 n-paraffins were low compared with those obtained for other adsorbents. The differential heat of adsorption values ensures the satisfactory separation of the components in the C5–C9 mixture under suitable chromatographic conditions.
•RHO-3 is essential for normal development of N. crassa.•RHO-3 displays a dynamic ring-shaped structure surrounding the inner core of the Spk.•The Δrho-3 strain is unable to produce ascospores.•The ...Δrho-3 strain showed a disaggregated and unstable Spk.
The Rho family of monomeric GTPases act as signaling proteins to establish and maintain cell polarity and other essential cellular processes. Rho3 is a GTPase of the Rho family that is exclusive of fungi that regulate cell polarity in yeast. However, studies have yet to explore its function in filamentous fungi. In this work, we investigated the role of RHO-3 in the model organism Neurospora crassa. Confocal microscopy analysis revealed that RHO-3 localizes in the outer region of the Spitzenkörper (Spk), in the plasma membrane from region II to the beginning of region III, and in the septa of mature hyphae. The phenotypic effect of the rho-3 deletion was analyzed. The results revealed that the rho-3 null strain showed severe defects in growth rate, aerial hyphae length, and conidia production. The organization of the Spk is also affected in the absence of RHO-3. Co-expression analysis of GFP-RHO-3 with glucan synthase 1 (GS-1-mChFP) and chitin synthase 1 (CHS-1-mChFP) revealed that RHO-3 localizes in the external region of the Spk in the macrovesicles zone. In summary, our results suggest that RHO-3 is not essential for the polarized growth of hyphae but plays a significant role in hyphal extension rate, conidiation, sexual reproduction and the integrity of the Spk, possibly regulating the delivery of macrovesicles to the apical dome.