Structure and function of a novel GH8 endoglucanase from the bacterial cellulose synthase complex of Raoultella ornithinolytica.

Cellulose synthesis in bacteria is a complex process involving the concerted action of several enzymes whose genes are often organized in operons. This process influences many fundamental physiological aspects such as bacteria and host interaction, biofilm formation, among others. Although it might sound contradictory, the participation of cellulose-degrading enzymes is critical to this process.

Comprehensive analysis of the cellulolytic system reveals its potential for deconstruction of lignocellulosic biomass in a novel Streptomyces sp.

The giant snail Achatina fulica is considered an invasive species in most territories in which it was introduced, due to its ability to process a large amount of lignocellulose as a consequence of the presence of a cellulolytic-associated microflora. Streptomyces are well known as crucial agents in the decomposition of complex polymers in soil environments and also as cellulolytic symbionts commonly associated with herbivore insects. Here, we employed a combination of genomic and biochemical tools for a detailed evaluation of the cellulolytic potential of Streptomyces sp.

Isolation of aerobic cultivable cellulolytic bacteria from different regions of the gastrointestinal tract of giant land snail Achatina fulica.

The enzymatic hydrolysis of cellulose by cellulases is one of the major limiting steps in the conversion of lignocellulosic biomass to yield bioethanol. To overcome this hindrance, significant efforts are underway to identify novel cellulases. The snail Achatina fulica is a gastropod with high cellulolytic activity, mainly due to the abundance of glycoside hydrolases produced by both the animal and its resident microbiota.

The NAC domain-containing protein, GmNAC6, is a downstream component of the ER stress- and osmotic stress-induced NRP-mediated cell-death signaling pathway.

Background: The endoplasmic reticulum (ER) is a major signaling organelle, which integrates a variety of responses against physiological stresses. In plants, one such stress-integrating response is the N-rich protein (NRP)-mediated cell death signaling pathway, which is synergistically activated by combined ER stress and osmotic stress signals. Despite the potential of this integrated signaling to protect plant cells against different stress conditions, mechanistic knowledge of the pathway is lacking, and downstream components have yet to be identified.

Complete inventory of soybean NAC transcription factors: sequence conservation and expression analysis uncover their distinct roles in stress response.

We performed an inventory of soybean NAC transcription factors, in which 101 NAC domain-containing proteins were annotated into 15 different subgroups, showing a clear relationship between structure and function. The six previously described GmNAC proteins (GmNAC1 to GmNAC6) were located in the nucleus and a transactivation assay in yeast confirmed that GmNAC2, GmNAC3, GmNAC4 and GmNAC5 function as transactivators. We also analyzed the expression of the six NAC genes in response to a variety of stress conditions.

The ER luminal binding protein (BiP) mediates an increase in drought tolerance in soybean and delays drought-induced leaf senescence in soybean and tobacco.

The ER-resident molecular chaperone BiP (binding protein) was overexpressed in soybean. When plants growing in soil were exposed to drought (by reducing or completely withholding watering) the wild-type lines showed a large decrease in leaf water potential and leaf wilting, but the leaves in the transgenic lines did not wilt and exhibited only a small decrease in water potential. During exposure to drought the stomata of the transgenic lines did not close as much as in the wild type, and the rates of photosynthesis and transpiration became less inhibited than in the wild type.

A PERK-like receptor kinase interacts with the geminivirus nuclear shuttle protein and potentiates viral infection.

The nuclear shuttle protein (NSP) from bipartite geminiviruses facilitates the intracellular transport of viral DNA from the nucleus to the cytoplasm and acts in concert with the movement protein (MP) to promote the cell-to-cell spread of the viral DNA. A proline-rich extensin-like receptor protein kinase (PERK) was found to interact specifically with NSP of Cabbage leaf curl virus (CaLCuV) and of tomato-infecting geminiviruses through a yeast two-hybrid screening. The PERK-like protein, which we designated NsAK (for NSP-associated kinase), is structurally organized into a proline-rich N-terminal domain, followed by a transmembrane segment and a C-terminal serine/threonine kinase domain.