Long-term exposure of Mytilus galloprovincialis to temperatures beyond 26oC triggers mussels' mortality. The present study aimed to integratively illustrate the correlation between intermediary metabolism, Hsp gene expression and oxidative stress related proteins in long-term thermally stressed Mytilus galloprovincialis and whether they are affected by thermal stress' magnitude and duration. We accordingly evaluated the gene expression profiles, in the posterior adductor muscle (PAM) and the mantle, concerning hsp70 and hsp90, and the antioxidant defense indicators Mn-SOD, Cu/Zn-SOD, catalase, glutathione S-transferase, and the metallothioneins mt-10 and mt-20. Moreover, we determined antioxidant enzymes' activities, oxidative stress through lipid peroxidation and activities of intermediary metabolism enzymes. The pattern of changes in relative mRNA expression levels indicate that mussels are able to sense thermal stress even when exposed to 22oC and before mussels' mortality is initiated. Data indicates a close correlation between the magnitude and duration of thermal stress with lipid peroxidation levels, changes in the activity of antioxidant enzymes and the enzymes of intermediary metabolism. The gene expression and increase in the activities of antioxidant enzymes support a scenario, according to which exposure to 24oC might trigger ROS production, which is closely correlated with anaerobic metabolism under hypometabolic conditions. Increase and maintenance of oxidative stress in conjunction with energy balance disturbance seems to trigger mussels' mortality after long term exposure at temperatures beyond 26oC. Eventually, in the context of preparation for oxidative stress, certain hypotheses and models are suggested, integrating the several steps of cellular stress response.

This paper is the first of a two part series devoted to describing relations between congruence and crystallographic braid groups. We recall and introduce some elements belonging to congruence braid groups and we establish some (iso)-morphisms between crystallographic braid groups and corresponding quotients of congruence braid groups.

Let U V Bn and U V Pn be the unrestricted virtual braid group and the unrestricted virtual pure braid group on n strands respectively. We study the groups U V Bn and U V Pn, and our main results are as follows: for n ≥ 5, we give a complete description, up to conjugation, to all possible homomorphisms from U V Bn to the symmetric group Sn. For n ≥ 3, we characterise all possible images of U V Bn, under a group homomorphism, to any finite group G. For n ≥ 5, we prove that U V Pn is a characteristic subgroup of U V Bn. In addition, we determine the automorphism group of U V Pn and we prove that Z 2 × Z 2 is a subgroup of the outer automorphism group of U V Bn. Lastly, we show that U V Bn and U V Pn are residually finite and Hopfian but not co-Hopfian. We also remark that some of these results hold accordingly for the welded braid group W Bn and we discuss about its automorphism group.

We show that the crystallographic braid group Bn/ [Pn, Pn] embeds naturally in the group of unrestricted virtual braids U V Bn, we give new proofs of known results about the torsion elements of Bn/ [Pn, Pn], and we characterise the torsion elements of U V Bn.

Let [Formula: see text] and [Formula: see text] be the unrestricted virtual braid group and the unrestricted virtual pure braid group on n strands, respectively. We study the groups [Formula: see text] and [Formula: see text], and our main results are as follows: for [Formula: see text], we give a complete description, up to conjugation, to all possible homomorphisms from [Formula: see text] to the symmetric group [Formula: see text]. For [Formula: see text], we characterize all possible images of [Formula: see text], under a group homomorphism, to any finite group [Formula: see text]. For [Formula: see text], we prove that [Formula: see text] is a characteristic subgroup of [Formula: see text]. In addition, we determine the automorphism group of [Formula: see text] and we prove that [Formula: see text] is a subgroup of the outer automorphism group of [Formula: see text]. Lastly, we show that [Formula: see text] and [Formula: see text] are residually finite and Hopfian but not co-Hopfian. We also remark that some of these results hold accordingly for the welded braid group [Formula: see text] and we discuss about its automorphism group.