The endochitinase gene chiA74 from Bacillus thuringiensis serovar kenyae strain LBIT-82 was cloned in Escherichia coli DH5␣F. A sequence of 676 amino acids was deduced when the gene was completely sequenced. A molecular mass of 74 kDa was estimated for the preprotein, which includes a putative 4-kDa signal sequence located at the N terminus. The deduced amino acid sequence showed high degree of identity with other chitinases such as ChiB from Bacillus cereus (98%) and ChiA71 from Bacillus thuringiensis serovar pakistani (70%). Additionally, ChiA74 showed a modular structure comprised of three domains: a catalytic domain, a fibronectin-like domain, and a chitin-binding domain. All three domains showed conserved sequences when compared to other bacterial chitinase sequences. A ca. 70-kDa mature protein expressed by the cloned gene was detected in zymograms, comigrating with a chitinase produced by the LBIT-82 wild-type strain. ChiA74 is active within a wide pH range (4 to 9), although a bimodal activity was shown at pH 4.79 and 6.34. The optimal temperature was estimated at 57.2°C when tested at pH 6. The potential use of ChiA74 as a synergistic agent, along with the B. thuringiensis insecticidal Cry proteins, is discussed.Bacillus thuringiensis is an insecticidal bacterium whose activity is based on the effect of single or mixed Cry or Cyt proteins, acting additively or synergistically, although antagonism has also been reported (9). Despite reports of more than 3,000 insect species, within 16 orders and susceptible to different B. thuringiensis toxins, important pests are highly susceptible to only a few toxins (14). Additionally, development of resistance to Cry proteins, their slow mode of action, and the requirement of ingestion, along with some other limitations, justify the search for new approaches to improve the conventional use of B. thuringiensis.The insect midgut is internally coated by the peritrophic membrane, whose structure is basically composed of proteins and reinforced with chitin fibers. This is a physical barrier to bacterial or viral infections but allows the flow of digested nutrients, minerals, and water towards the midgut epithelium. It is known that the approach of ␦-endotoxins of B. thuringiensis to the microvillus receptor is highly facilitated when the peritrophic membrane is damaged or degraded, causing an increase in its insecticidal activity (25). Factors that damage the peritrophic membrane, such as the enhancin of granuloviruses, promote the insecticidal activity of commercial formulations of B. thuringiensis, especially on those pests with relatively low natural susceptibility, such as Helicoverpa zea (Boddie) and Spodoptera exigua (Hübner) (16). Likewise, the same effect is observed when Cry proteins are tested along with wild-type (31) or recombinant (11) chitinolytic bacteria, as well as with unpurified chitinase (Chi) (25,40).On the other hand, chitinases from B. thuringiensis are poorly studied (2, 7, 15), although interest has slowly increased due to their potential role as...

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Nowadays, overweight and obesity are increasing in young people, resulting in several health problems. New scientific evidence shows that consuming too much fructose, a basic type of sugar, can cause some of these problems. Sugary foods such as soft drinks are sweetened with syrups that have very high fructose content. Drinking too much of these beverages results in weight gain from the accumulation of body fat. Scientists have also found that, in children, consuming excessive amounts of fructose can harm the liver, lungs, and heart. This article will explain how fructose in sweetened beverages leads to overweight and obesity in children and adolescents, highlighting the alarming number of young people all over the world who suffer from these diseases and what can be done to prevent this situation.

The purpose of this paper was to evaluate the effect of thermal treatment (TT: 121 ± 2 °C, 15 min) on the composition of commercial sweeteners diluted in water (10 °Brix). Additionally, we evaluated the impact of this TT on metabolic responses in C57BL/6 mice during a 24-week treatment. The sweeteners included in this study were sucrose (SC), glucose-63 (GLU63), agave syrup (AS), sucralose (SUC), and steviol glycosides (STG). HPLC analysis showed changes in the concentration of simple sugars of GLU63 and AS after TT. Importantly, in all sweeteners, TT modulated metabolic responses in mice. The mice drinking thermally treated sweetener solution showed an increase of 10–13% (p < 0.05) in food intake (AS, SUC, and STG), beverage intake (2–21%; SC and GLU63), weight gain (38%; SUC), energy (10–13%; AS, SUC, and STG), glucose levels (11–17%; SC and STG), GLP-1 (30%; SC) and insulin (88%; AS) release, and the generation of protein carbonyl (SC) and malondialdehyde (all sweeteners tested) compared to mice drinking solution without TT. In conclusion, TT of sweetener solutions accentuates the metabolic responses of healthy mice, which can be related to overweight and its comorbidities.