Mechanisms of Egg Yolk Formation and Implications on Early Life History of White Perch (Morone americana).

The three white perch (Morone americana) vitellogenins (VtgAa, VtgAb, VtgC) were quantified accurately and precisely in the liver, plasma, and ovary during pre-, early-, mid-, and post-vitellogenic oocyte growth using protein cleavage-isotope dilution mass spectrometry (PC-IDMS). Western blotting generally mirrored the PC-IDMS results. By PC-IDMS, VtgC was quantifiable in pre-vitellogenic ovary tissues and VtgAb was quantifiable in pre-vitellogenic liver tissues however, neither protein was detected by western blotting in these respective tissues at this time point. Immunohistochemistry indicated that VtgC was present within pre-vitellogenic oocytes and localized to lipid droplets within vitellogenic oocytes. Affinity purification coupled to tandem mass spectrometry using highly purified VtgC as a bait protein revealed a single specific interacting protein (Y-box binding protein 2a-like [Ybx2a-like]) that eluted with suramin buffer and confirmed that VtgC does not bind the ovary vitellogenin receptors (LR8 and Lrp13). Western blotting for LR8 and Lrp13 showed that both receptors were expressed during vitellogenesis with LR8 and Lrp13 expression highest in early- and mid-vitellogenesis, respectively. The VtgAa within the ovary peaked during post-vitellogenesis, while VtgAb peaked during early-vitellogenesis in both white perch and the closely related striped bass (M. saxatilis). The VtgC was steadily accumulated by oocytes beginning during pre-vitellogenesis and continued until post-vitellogenesis and its composition varies widely between striped bass and white perch. In striped bass, the VtgC accounted for 26% of the vitellogenin-derived egg yolk, however in the white perch it comprised only 4%. Striped bass larvae have an extended developmental window and these larvae have yolk stores that may enable them to survive in the absence of food for twice as long as white perch after hatch. Thus, the VtgC may play an integral role in providing nutrients to late stage fish larvae prior to the onset of exogenous feeding and its composition in the egg yolk may relate to different early life histories among this diverse group of animals

Label-free quantitative proteomics of enriched nuclei from sugarcane (saccharum ssp) stems in response to drought stress

Drought is considered the major abiotic stress limiting crop productivity. This study seeks to identify proteins involved in the drought response in sugarcane stems submitted to drought stress. The integration of nuclei enrichment sample preparation with the shotgun proteomic approach results in great coverage of the sugarcane stem proteome with 5381 protein groups identified. A total of 1204 differentially accumulated proteins are detected in response to drought, among which 586 and 618 are increased and reduced in abundance, respectively. A total of 115 exclusive proteins are detected, being 41 exclusives of drought-stressed plants and 74 exclusives of control plants. In the control plants, most of these proteins are related to cell wall metabolism, indicating that drought affects negatively the cell wall metabolism. Also, 37 transcription factors (TFs) are identified, which are low abundant nuclear proteins and are differentially accumulated in response to drought stress. These TFs are associated to protein domains such as leucine-rich (bZIP), C2H2, NAC, C3H, LIM, Myb-related, heat shock factor (HSF) and auxin response factor (ARF). Increased abundance of chromatin remodeling and RNA processing proteins are also observed. It is suggested that these variations result from an imbalance of protein synthesis and degradation processes induced by drought1914CNPQ - Conselho Nacional de Desenvolvimento Científico e TecnológicoFAPESP – Fundação de Amparo à Pesquisa Do Estado De São Paulo008/58035-6; 2013/10779-5; 14/25994-1; 2016/06236sem informaçã

Quantitative proteomic analysis of tomato genotypes with differential cadmium tolerance

This is a report on comprehensive characterization of cadmium (Cd)-exposed root proteomes in tomato using label-free quantitative proteomic approach. Two genotypes differing in Cd tolerance, Pusa Ruby (Cd-tolerant) and Calabash Rouge (Cd-sensitive), were exposed during 4 days to assess the Cd-induced effects on root proteome. The overall changes in both genotypes in terms of differentially accumulated proteins (DAPs) were mainly associated to cell wall, redox, and stress responses. The proteome of the sensitive genotype was more responsive to Cd excess, once it presented higher number of DAPs. Contrasting protein accumulation in cellular component was observed: Cd-sensitive enhanced intracellular components, while the Cd-tolerant increased proteins of extracellular and envelope regions. Protective and regulatory mechanisms were different between genotypes, once the tolerant showed alterations of various protein groups that lead to a more efficient system to cope with Cd challenge. These findings could shed some light on the molecular basis underlying the Cd stress response in tomato, providing fundamental insights for the development of Cd-safe cultivars26252603926051CAPES - Coordenação de Aperfeiçoamento de Pessoal e Nível SuperiorCNPQ - Conselho Nacional de Desenvolvimento Científico e TecnológicoFAPESP – Fundação de Amparo à Pesquisa Do Estado De São Paulonão tem303749/2016-42009/54676-0; 2016/14349-

Hematoxylin and eosin staining of representative white perch ovary tissue sections.

<p>Ovary tissues were sampled at four key time points across one reproductive year during (A) pre-vitellogenesis (PreVG), (B) early-vitellogenesis (EVG), (C) mid-vitellogenesis (MVG), and (D) post-vitellogenesis (PostVG). Scale bar is 500 microns.</p

Average survival duration of food-restricted white perch and striped bass larvae.

<p>Dashed boxes indicate approximate time of hatching (~2 days) and onset of first feeding (~4 days in white perch, ~8 days in striped bass). [Mansuetti, 1964; Eldridge, et al., 1981; North & Houde, 2003].</p

Confocal microscopy of anti-VtgC coupled to DyLight633.

<p>Confocal microscopy images of immunohistochemistry of mature female white perch ovary tissues across one reproductive year stained with anti-VtgC coupled to DyLight633: (A) pre-vitellogenic (PreVG), (B) early-vitellogenic (EVG), (C) mid-vitellogenic (MVG), and (D) post-vitellogenic (PostVG) ovary sections.</p

Sexually mature female white perch sampling statistics.

<p>Sexually mature female white perch sampling statistics.</p

Vitellogenin composition in white perch and striped bass egg yolk.

<p>In white perch (<i>M</i>. <i>americana</i>), yolk proteins derived from VtgC are minor components of the total egg yolk (< 5%), whereas in striped bass (<i>M</i>. <i>saxatilis</i>) they are major components of the egg yolk (~ 25%). [Williams et al., 2014 (J Exp Zool Part A); Schilling et al., 2014 (J Proteome Res)].</p