Phytochemical screening and anti-oxidant activity of Sargassum wightii enhances the anti-bacterial activity against Pseudomonas aeruginosa

In this study, the phytochemical, phenolic, flavonoid and bioactive compounds were successfully screened from crude extract of Sargassum wightii by LC-MS analysis after NIST interpretation. Bacterial growth inhibition study result was shown with 24 mm zone inhibition at 200 µg/mL concentration against P. aeruginosa. The increased phenolic content was much closed to gallic acid and the range was observed at 250 μg/mL concentration. In addition, flavonoid contents of the algae extract was indicated more significant with rutin at 200 μg/mL. In result, both the phenolic and flavonoid contents of the extract were more correlated with gallic acid and rutin. Further, the total anti-oxidant and DPPH radical scavenging activities were shown increased activity at 200 μg/mL concentrations. Furthermore, the excellent anti-bacterial alteration result was observed at 200 μg/mL concentration by minimum inhibition concentration. Therefore, the result was revealed that the marine algae Sargassum wightii has excellent phytochemical and anti-oxidant activities, and it has improved anti-bacterial activity against P. aeruginosa.     

Enhanced decolorization of Solar brilliant red 80 textile dye by an indigenous white rot fungus Schizophyllum commune IBL-06

An indigenously isolated white rot fungus, Schizophyllum commune IBL-06 was used to decolorize Solar brilliant red 80 direct dye in Kirk’s basal salts medium. In initial screening study, the maximum decolorization (84.8%) of Solar brilliant red 80 was achieved in 7 days shaking incubation period at pH 4.5 and 30 °C. Different physical and nutritional factors including pH, temperature and fungal inoculum density were statistically optimized through Completely Randomized Design (CRD), to enhance the efficiency of S. commune IBL-06 for maximum decolorization of Solar brilliant red 80 dye. The effects of inexpensive carbon and nitrogen sources were also investigated. Percent dye decolorization was determined by a reduction in optical density at the wavelength of maximum absorbance (λ_max, 590 nm). Under optimum conditions, the S. commune IBL-06 completely decolorized (100%) the Solar brilliant red 80 dye using maltose and ammonium sulfate as inexpensive carbon and nitrogen sources, respectively in 3 days. S. commune IBL-06 produced the three major ligninolytic enzymes lignin peroxidase (LiP), manganase peroxidase (MnP) and lacaase (Lac) during the decolorization of Solar brilliant red 80. LiP was the major enzyme (944 U/mL) secreted by S. commune IBL-06 along with comparatively lower activities of MnP and Laccase.     

3D Vertically Aligned and Interconnected Porous Carbon Nanosheets as Sulfur Immobilizers for High Performance Lithium‐Sulfur Batteries

A unique nanostructure of 3D and vertically aligned and interconnected porous carbon nanosheets (3D‐VCNs) is demonstrated by a simple carbonization of agar. The key feature of 3D‐VCNs is that they possess numerous 3D channels with macrovoids and mesopores, leading to high surface area of 1750 m² g^?1, which play an important role in loading large amount of sulfur, while vertically aligned microporous carbon nanosheets act as the multilayered physical barrier against polysulfides anions and prevent their dissolution in the electrolyte due to strong adsorption during cycling process. As a result, the 3D hybrid (3D‐S‐VCNs) infiltered with 68.3 wt% sulfur exhibits a high and stable reversible capacity of 844 mAh g^?1 at the current density of 837 mA g^?1 with excellent Coulombic efficiency ≈100%, capacity retention of ≈80.3% over 300 cycles, and good rate ability (the reversible capacity of 738 mAh g^?1 at the high current density of 3340 mA g^?1). The present work highlights the vital role of the introduction of 3D carbon nanosheets with macrovoids and mesopores in enhancing the performance of LSBs.     

A Novel MAPKK Involved in Cell Death and Defense Signaling

A high-throughput in planta overexpression screen of a Nicotiana benthamiana cDNA library identified a mitogen activated protein kinase kinase (MAPKK), NbMKK1, as a potent inducer of hypersensitive response (HR)-like cell death. NbMKK1-mediated cell death was attenuated in plants whereby expression of NbSIPK, an ortholog of tobacco SIPK and Arabidopsis AtMPK6, was knocked down by virus-induced gene silencing (VIGS), suggesting that NbMKK1 functions upstream of NbSIPK. In accordance with this result, NbMKK1 phosphorylated NbSIPK in vitro, and furthermore NbMKK1 and NbSIPK physically interacted in yeast two-hybrid assay. VIGS of NbMKK1 in N. benthamiana resulted in a delay of Phytophthora infestans INF1 elicitin-mediated HR as well as in the reduction of resistance against a non-host pathogen Pseudomonas cichorii. Our data of NbMKK1, together with that of LeMKK4,¹ demonstrate the presence of a novel defense signaling pathway involving NbMKK1/LeMKK4 and SIPK.Key Words: MAPK, defense, cell death, in planta screenMitogen activated protein kinase (MAPK) cascades are highly conserved signaling pathways in eukaryotes, comprising three tiered classes of protein kinase, MAPKKK (MAPKK kinase), MAPKK and MAPK, that sequentially relay phosphorylation signals.² The Arabidopsis genome carries genes for 20 MAPKs, 10 MAPKKs³ and more than 25 MAPKKKs.⁴ In plants, MAPK signaling is known to function in various biotic^4,5 and abiotic⁶ stress responses and cytokinesis.⁷ In defense signaling, extensive research has been carried out for two tobacco MAPKs, SIPK⁸ (salicylic-acid-induced protein kinase; hereafter designated as NtSIPK) and WIPK⁹ (wound-induced protein kinase = NtWIPK), and their orthologs in Arabidopsis¹⁰ (AtMPK6 and ATMPK3, respectively), partly because kinase activities of these two MAPKs are easy to detect by an in gel kinase assay using myeline basic protein (MBP) as substrate.¹¹ Both NtSIPK and NtWIPK are activated by the interaction between host resistance (R)- gene and cognate avirulence gene of pathogen^11,12 and elicitor perception by host cells.^13,14 Shuqun Zhang and his group showed that an upstream kinase of both NtSIPK and NtWIPK is NtMEK2.¹⁵ Transient overexpression of constitutively active NtMEK2 caused phosphorylation of NtSIPK and NtWIPK, resulting in rapid HR-like cell death in tobacco leaves.¹⁵ Later, the same lab showed that overexpression of NtSIPK alone also caused HR-like cell death.¹⁶ The downstream target proteins of NtSIPK and AtMPK6 are being identified and include 1-aminocyclopropane-1-carboxylic acid sythase-6 (ACS-6).^17,18 Although recent studies identified another MAPK cascade (NtMEK1 → Ntf6) involved in defense responses^19,20 we can still say that the current research focus of MAPK defense signaling centers around the cascade comprising [NtMEK2→ NtSIPK/NtWIPK→ target proteins] of tobacco and its orthologous pathways in other plant species.In an effort to search for plant genes involved in HR-like cell death, we have been employing a high-throughput in planta expression screen of N. benthamiana cDNA libraries. In this experimental system, a cDNA library was made in a binary potato virus X (PVX)-based expression vector pSfinx.²¹ The cDNA library was transferred to Agrobacterium tumefaciens, and 40,000 of the bacterial colonies were individually inoculated by toothpicks onto leaf blades of N. benthamiana leaves. The phenotype around the inoculated site was observed 1–2 weeks following the inoculation. This rapid screen identified 30 cDNAs that caused cell death after overexpression, including genes coding for ubiquitin proteins, RNA recognition motif (RRM) containing proteins, a class II ethylene-responsive element binding factor (EREBP)-like protein²² and a MAPKK protein (this work). Such an in planta screening technique has been used before for the isolation of fungal²¹ and oomycete^23,24 elicitors and necrosis inducing genes, but not for isolation of plant genes. Overexpression screening of cDNA libraries is a common practice in prokaryotes, yeast and amimal cells,^25,26 so it is a surprise that this approach has not been systematically applied in plants. Given its throughput, we propose that this virus-based transient overexpression system is a highly efficient way to isolate novel plant genes by functional screen.²⁷ Since overexpression frequently causes non-specific perturbation of signaling, genes identified by overexpression should be further validated by loss-of-function assays, for instance, VIGS.²⁸Overexpression of the identified MAPKK gene, NbMKK1, triggered a rapid generation of H₂O₂, followed by HR-like cell death in N. benthamiana leaves (this work). NbMKK1-GFP fusion protein overexpression also caused cell death, and curiously NbMKK1-GFP was shown to localize consistently in the nucleus. Sequence comparison classified NbMKK1 to the Group D of MAPKKs about which little information is available. So far, a MAPKK, LeMKK4, from tomato belonging to the Group D MAPKKs, was shown to cause cell death after overexpression.¹ Based on amino acid sequence similarity and phylogenetic analyses, LeMKK4 and NbMKK1 seem to be orthologs. To see whether NbMKK1 transduces signals through SIPK and WIPK, we performed NbMKK1 overexpression in N. benthamiana plants whereby the expression of either NbSIPK or NbWIPK (WIPK ortholog in N. benthamiana) was silenced by VIGS. NbMKK1 did not induce cell death in NbSIPK-silenced plants, suggesting that the NbMKK1 cell death signal is transmitted through NbSIPK. Indeed, NbMKK1 phosphorylated NbSIPK in vitro, and NbMKK1 and NbSIPK physically interacted in yeast two-hybrid assay. These results suggest that NbMKK1 interacts with NbSIPK, most probably with its N-terminal docking domain, and phosphorylates NbSIPK in vivo to transduce the cell death signal downstream.NbMKK1 exhibits constitutive expression in leaves. To determine the function of NbMKK1 in defense, we silenced NbMKK1 by VIGS, and such plants were challenged with Phytophthora infestans INF1 elicitin²⁹ and Pseudomonas cichorii, a non-host pathogen. INF1-mediated HR cell death was remarkably delayed in NbMKK1-silenced plants. Likewise, plant defense against P. cichorii was compromised in NbMKK1-silenced plants. These results indicate that NbMKK1 is an important component of signaling of INF1-mediated HR and non-host resistance to P. cichorii.Together, our analyses of NbMKK1 and independent work from Greg Martin''s lab on LeMKK4¹ suggest that a Group D MAPKK, NbMKK1/LeMKK4, functions upstream of SIPK and transduces defense signals in these solanaceous plants (Fig. 1). In plants as well as in other eukaryotes, it is common that kinases have multiple partners. The work on these kinases fits this concept. A single MAPK (e.g., SIPK) is phosphorylated by multiple MAPKKs (e.g., NtMEK2 and NbMKK1), and a single MAPKK (e.g., NtMEK2) can phosphorylate multiple MAPKs (e.g., NtSIPK and NtWIPK).Open in a separate windowFigure 1Defense signaling through NbMKK1/LeMKK4. Two defense signal pathways involving NtMEK2 (indicated as MEK2) → WIPK/SIPK and NtMEK1(indicated as MEK1) → Ntf6 are well documented. By our and Pedley and Martin''s¹ works, another novel MAPKK, NbMKK1/LeMKK4 was demonstrated to participate in defense signaling by phosphorylation of SIPK.     

Nasal Staphylococcus aureus and S. pseudintermedius carriage in healthy dogs and cats: a systematic review of their antibiotic resistance,virulence and genetic lineages of zoonotic relevance

The molecular ecology of Staphylococcus aureus, Staphylococcus pseudintermedius and their methicillin-resistant strains in healthy dogs and cats could serve as good models to understand the concept of bacterial zoonosis due to animal companionship. This study aims to provide insights into pooled prevalence, genetic lineages, virulence and antimicrobial resistance (AMR) among healthy dogs and cats. Original research and brief communication articles published from 2001 to 2021 that reported the nasal detection of S. aureus and S. pseudintermedius in healthy dogs and cats in the community, homes and outside veterinary clinics were examined and analysed. Forty-nine studies were eligible and included in this systematic review. The pooled prevalence of nasal carriage of S. aureus/methicillin-resistant S. aureus (MRSA) in healthy dogs and cats were 10.9% (95% CI: 10.1–11.9)/2.8% (95% CI: 2.4–3.2) and 3.2% (95% CI: 1.9–4.8)/0.5% (95% CI: 0.0–1.1), respectively. Conversely, the pooled prevalence of S. pseudintermedius/methicillin-resistant S. pseudintermedius (MRSP) in healthy dogs and cats were 18.3% (95% CI: 17.1–19.7)/3.1% (95% CI: 2.5–3.7) and 1.3% (95% CI: 0.6–2.4)/1.2% (95% CI: 0.6–2.3), respectively. Although highly diverse genetic lineages of S. aureus were detected in healthy dogs and cats, MSSA-CC1/CC5/CC22/CC45/CC121/CC398 and MRSA-CC5/CC93/CC22/CC30 were mostly reported in dogs; and MSSA-CC5/CC8/CC15/CC48 and MRSA-CC22/CC30/CC80 in cats. Of note, MSSA-CC398 isolates (spa-types t034 and t5883) were detected in dogs. Genetic lineages often associated with MSSP/MRSP were ST20/ST71, highlighting the frequent detection of the epidemic European MRSP-ST71 clone in dogs. S. aureus isolates carrying the luk-S/F-PV, tst, eta, etb and etd genes were seldomly detected in dogs, and luk-S/F-PV was the unique virulence factor reported in isolates of cats. S. pseudintermedius isolates harbouring the luk-S/F-I, seint and expA genes were frequently found, especially in dogs. High and diverse rates of AMR were noted, especially among MRSA/MRSP isolates. There is a need for additional studies on the molecular characterization of isolates from countries with under-studied nasal staphylococci isolates.     

Telomere loss in relation to age and early environment in long-lived birds

Shortening of telomeres, specific nucleotide repeats that cap eukaryotic chromosomes, is thought to play an important role in cellular and organismal senescence. We examined telomere dynamics in two long-lived seabirds, the European shag and the wandering albatross. Telomere length in blood cells declines between the chick stage and adulthood in both species. However, among adults, telomere length is not related to age. This is consistent with reports of most telomere loss occurring early in life in other vertebrates. Thus, caution must be used in estimating annual rates of telomere loss, as these are probably not constant with age. We also measured changes within individuals in the wild, using repeat samples taken from individual shags as chicks and adults. We found high inter-individual variation in the magnitude of telomere loss, much of which was explained by circumstances during growth. Individuals laying down high tissue mass for their size showed greater telomere shortening. Independently of this, individuals born late in the season showed more telomere loss. Early conditions, possibly through their effects on oxidative stress, appear to play an important role in telomere attrition and thus potentially in the longevity of individuals.     

Human prorenin has "gate and handle" regions for its non-proteolytic activation

We investigated the mechanism for non-proteolytic activation of human prorenin using five kinds of antibodies. Each of the antigens, L1PPTDTTTFKRI11P, T7PFKRIFLKRMP17P, I11PFLKRMPSIRESLKER26P, M16PPSIRESLKER26P, and G27PVDMARLGPEWSQPM41P, was designed from the tertiary structure of predicted prorenin. These antibodies were labeled anti-01/06, anti-07/10, anti-11/26, anti-16/26, and anti-27/41, respectively, for their binding specificities. Inactive recombinant human prorenin (0.1 nM) bound to various concentrations of anti-01/06, anti-11/26, and anti-27/41 antibodies at 4 degrees C with equilibrium dissociation constants of 138, 41, and 22 nM, respectively. However, intact prorenin (0.1 nM) did not show significant binding to 200 nM anti-07/10 and anti-16/26 antibodies for 20 h. Ninety percent of prorenin (0.1 nM) was found to be non-proteolytically activated by incubation with anti-11/26 antibodies (200 nM) at 4 degrees C for 20 h. Prorenin was not active even under complex with either anti-01/06 or anti-27/41 antibodies. Prorenin was also reversibly activated at pH 3.3 and 4 degrees C for 25 h. The acid-activated prorenin bound to anti-07/10 and anti-16/26 antibodies as well as to anti-01/06, anti-11/15, and anti-27/41 antibodies at neutral pH and 4 degrees C in 2 h. Their dissociation constants were 13, 40, 8.6, 3.6, and 14 nM, respectively. The acid-activated prorenin was re-inactivated by incubation at pH 7.4 and 4 degrees C in 50 h. Anti-07/10 and anti-11/26 antibodies inhibited such re-inactivation at 25 degrees C by more than 90% and 50%, respectively, whereas other kinds of antibodies did not prevent the re-inactivation at 25 degrees C. These results indicate that prorenin has "gate" (T7PFKR10P) and "handle" (I11PFLKR15P) regions critical for its non-proteolytic activation.