The structure and properties of different types of starch exposed to UV radiation: A comparative study

The effect of UV-irradiation on four different types of native starch (corn, waxy corn, wheat and potato) have been investigated. Although the changes in the chemical structure of starch specimens were small, indicating good photostability, the samples lost adsorbed water and their crystallinity degree decreased after irradiation. Moreover, a drop in average molecular weight occurred in samples (with the exception of potato starch) as a result of main chain scission. The variations in the properties of investigated specimens of various origin were related to the differences in their structure and macromolecular arrangement. The lowest photostability among the four starches was exhibited by potato starch.     

The SARS-CoV-2 Spike protein has a broad tropism for mammalian ACE2 proteins

SARS Coronavirus 2 (SARS-CoV-2) emerged in late 2019, leading to the Coronavirus Disease 2019 (COVID-19) pandemic that continues to cause significant global mortality in human populations. Given its sequence similarity to SARS-CoV, as well as related coronaviruses circulating in bats, SARS-CoV-2 is thought to have originated in Chiroptera species in China. However, whether the virus spread directly to humans or through an intermediate host is currently unclear, as is the potential for this virus to infect companion animals, livestock, and wildlife that could act as viral reservoirs. Using a combination of surrogate entry assays and live virus, we demonstrate that, in addition to human angiotensin-converting enzyme 2 (ACE2), the Spike glycoprotein of SARS-CoV-2 has a broad host tropism for mammalian ACE2 receptors, despite divergence in the amino acids at the Spike receptor binding site on these proteins. Of the 22 different hosts we investigated, ACE2 proteins from dog, cat, and cattle were the most permissive to SARS-CoV-2, while bat and bird ACE2 proteins were the least efficiently used receptors. The absence of a significant tropism for any of the 3 genetically distinct bat ACE2 proteins we examined indicates that SARS-CoV-2 receptor usage likely shifted during zoonotic transmission from bats into people, possibly in an intermediate reservoir. Comparison of SARS-CoV-2 receptor usage to the related coronaviruses SARS-CoV and RaTG13 identified distinct tropisms, with the 2 human viruses being more closely aligned. Finally, using bioinformatics, structural data, and targeted mutagenesis, we identified amino acid residues within the Spike–ACE2 interface, which may have played a pivotal role in the emergence of SARS-CoV-2 in humans. The apparently broad tropism of SARS-CoV-2 at the point of viral entry confirms the potential risk of infection to a wide range of companion animals, livestock, and wildlife.

A study using a combination of surrogate entry assays and live virus suggests that SARS-CoV-2 may have a broad host-range, revealing that the virus''s spike protein can use a broad range of host ACE2 receptors to enter cells and that the sequence of this protein might have changed during the zoonotic jump into humans.     

Interaction between the predator Xylocoris sordidus and Bacillus thuringiensis bioinsecticides

Xylocoris species (Hemiptera: Anthocoridae) are known to occur in various habitats and attack a diversity of agriculturally important prey. Other groups of organisms, such as strains of Bacillus thuringiensis Berliner (Bt) bacteria, also have been extensively studied and applied as biological control agents. The use of these Bt-bioinsecticides in association with predators may be a good strategy in integrated pest management. This work had the objective to study predator behaviour, predatory capacity, and functional response of fifth-instar nymphs of Xylocoris sordidus (Reuter) to eggs of Plutella xylostella (L.) (Lepidoptera: Plutellidae) and Corcyra cephalonica (Stainton) (Lepidoptera: Pyralidae) treated with one of three commercial Bt-bioinsecticides. The predator presented a type II functional response to untreated P. xylostella eggs (control) and to eggs treated with Agree, whereas the response was type III to P. xylostella eggs treated with Xentari and Dipel. However, on a diet of C. cephalonica eggs the predator displayed a type II response curve on eggs treated with each of the three bioinsecticides, and a type III response on untreated eggs. Bioinsecticides based on B. thuringiensis may be used in association with X. sordidus predators to control lepidopterous pest species.