Photosynthetic organisms, such as higher plants and algae, require light to survive. However, an excessive amount of light can be harmful due to the production of reactive oxygen species (ROS), which cause cell damage and, if it is not effectively regulated, cell death. The study of plants’ responses to light can aid in the development of methods to improve plants’ growth and productivity. Due to the multicellular nature of plants, there may be variations in the results based on plant age and tissue type. Chlamydomonas reinhardtii, a unicellular green alga, has also been used as a model organism to study photosynthesis and photoprotection. Nonetheless, the majority of the research has been conducted with strains that have been consistently utilized in laboratories and originated from the same source. Despite the availability of many field isolates of this species, very few studies have compared the light responses of field isolates. This study examined the responses of two field isolates of Chlamydomonas to high light stress. The light-tolerant strain, CC-4414, managed reactive oxygen species (ROS) slightly better than the sensitive strain, CC-2344, did. The proteomic data of cells subjected to high light revealed cellular modifications of the light-tolerant strain toward membrane proteins. The morphology of cells under light stress revealed that this strain utilized the formation of palmelloid structures and cell aggregation to shield cells from excessive light. As indicated by proteome data, morphological modifications occur simultaneously with the increase in protein degradation and autophagy. By protecting cells from stress, cells are able to continue to upregulate ROS management mechanisms and prevent cell death. This is the first report of palmelloid formation in Chlamydomonas under high light stress.

Nonedible materials such as agricultural wastes can serve as sources of antimicrobial peptides (AMPs) effective against bacterial plant pathogens. In this study, thirteen agricultural samples were collected and their protein hydrolysates obtained using pepsin. Peptides smaller than 3 kDa were purified by reverse-phase chromatography, cation exchange chromatography, and pI-based fractionation and tested for activity against plant pathogenic bacteria at each step. Active peptides were then analyzed for putative mechanisms using nanoLC–MS/MS and the Mascot program. Ultimately, eight candidate peptides originating from bagasse were selected and chemically synthesized for a comparative study of growth inhibition in plant pathogenic bacteria and plant growth-promoting rhizobacteria (PGPRs). Three synthesized peptides exhibited a potent activity against plant pathogenic bacteria while also supporting the growth of PGPRs. Proteomics analysis revealed the peptides PQLAVF (Pro-Gln-Leu-Ala-Val-Phe) and MDRFL (Met-Asp-Arg-Phe-Leu) to act against Xanthomonas oryzae pv. oryzae via membrane-active mechanisms, while peptide VQLMNSL (Val-Gln-Leu-Met-Asn-Ser-Leu) acted against Pectobacterium carotovorum and Agrobacterium rhizogenes through intracellular-active mechanisms. Further study remains necessary to customize peptides by amino acid substitution not only for a higher effective activity against these and other critical pathogens, but also for a higher stability of peptides in critical condition when applied in industrial processes in the future.

Sepsis is a crucial public health problem with a high mortality rate caused by a dysregulated host immune response to infection. Vascular endothelial cell injury is an important hallmark of sepsis, which leads to multiple organ failure and death. Early biomarkers to diagnose sepsis may provide early intervention and reduce risk of death. Damage-associated molecular patterns (DAMPs) are host nuclear or cytoplasmic molecules released from cells following tissue damage. We postulated that DAMPs could potentially be a novel sepsis biomarker. We used an in vitro model to determine suitable protein–DAMPs biomarkers for early sepsis diagnosis. Low and high lipopolysaccharide (LPS) doses were used to stimulate the human umbilical vein endothelial cell line EA.hy926 for 24, 48, and 72 h. Results showed that cell viability was reduced in both dose-dependent and time-dependent manners. Cell injury was corroborated by a significant increase in lactate dehydrogenase (LDH) activity within 24 h in cell-conditioned medium. Secreted protein–DAMPs in the supernatant, collected at different time points within 24 h, were characterized using shotgun proteomics LC-MS/MS analysis. Results showed that there were 2233 proteins. Among these, 181 proteins from the LPS-stimulated EA.hy926 at 1, 12, and 24 h were significantly different from those of the control. Twelve proteins were up-regulated at all three time points. Furthermore, a potential interaction analysis of predominant DAMPs-related proteins using STITCH 5.0 revealed the following associations with pathways: response to stress; bacterium; and LPS (GO:0080134; 0009617; 0032496). Markedly, alpha-2-HS-glycoprotein (AHSG or fetuin-A) and lactotransferrin (LTF) potentially presented since the first hour of LPS stimulation, and were highly up-regulated at 24 h. Taken together, we reported proteomic profiling of vascular endothelial cell-specific DAMPs in response to early an in vitro LPS stimulation, suggesting that these early damage-response protein candidates could be novel early biomarkers associated with sepsis.

The occurrence of Cryptococcus neoformans, the human fungal pathogen that primarily infects immunocompromised individuals, has been progressing at an alarming rate. The increased incidence of infection of C. neoformans with antifungal drugs resistance has become a global concern. Potential antifungal agents with extremely low toxicity are urgently needed. Herein, the biological activities of recombinant javanicin (r-javanicin) against C. neoformans were evaluated. A time-killing assay was performed and both concentration- and time-dependent antifungal activity of r-javanicin were indicated. The inhibitory effect of the peptide was initially observed at 4 h post-treatment and ultimately eradicated within 36 to 48 h. Fungal outer surface alteration was characterized by the scanning electron microscope (SEM) whereas a negligible change with slight shrinkage of external morphology was observed in r-javanicin treated cells. Confocal laser scanning microscopic analysis implied that the target(s) of r-javanicin is conceivably resided in the cell thereby allowing the peptide to penetrate across the membrane and accumulate throughout the fungal body. Finally, cryptococcal cells coped with r-javanicin were preliminarily investigated using label-free mass spectrometry-based proteomics. Combined with microscopic and proteomics analysis, it was clearly elucidated the peptide localized in the intracellular compartment where carbohydrate metabolism and energy production associated with glycolysis pathway and mitochondrial respiration, respectively, were principally interfered. Overall, r-javanicin would be an alternative candidate for further development of antifungal agents.

This study investigated the anticancer efficacy of <3 kDa fractions derived from native peptides and protein hydrolysate of Varanus saltator serum. The inhibitory effects of these fractions were evaluated against a panel of cancer cell lines (A375, CaCO2, CAL27, NCI-H460, HeLa, HCT8, HT29, HepG2, KATO III, MCF-7, MDA-MB-231, Raw264.7, SKOV-3, SW620, T47D, and U937) and normal cell lines (HaCaT, MRC5, and Vero). Native peptides demonstrated higher anticancer activity compared to protein hydrolysates, inhibiting 16 cell lines and exhibiting high efficacy (≥70% inhibition) against CaCO2, CAL27, HaCaT, HT29, HepG2, MCF-7, MRC5, and U937. These native peptides were further fractionated by stepwise reverse-phase column chromatography. The hydrophilic (C18 unbound) peptide fraction exhibited greater anticancer activity than the hydrophobic (C18 bound) fraction. In addition, by LC-MS analysis, the peptide sequences were screening in silico. The predictions showed that 159 of the 432 Varanus peptides had the potential to be anticancer peptides (ACPs), of which the top twenty had a probability of more than 75%. The anticancer mechanism of peptides may be explained by the mechanism of cell entry or action. Further peptide synthesis and modification should be the next step to enhance the anticancer efficacy of these peptides with less toxicity to Vero cells. This finding sets the way for the development of new anticancer drugs originating from Varanus salvator serum peptides.

Background: The flowering transition is a critical process determining the onset of reproductive development and fruit production. The molecular mechanisms underlying this process in coconuts are poorly understood; however, recent studies have identified CnHd3a as a potential regulator of the floral transition in coconuts. Methods: In this study, we characterized the molecular structure of CnHd3a and analyzed its alternative splicing forms in tall and dwarf varieties of coconut palms during the flowering transition. We used qRT-PCR to measure the expression levels of CnHd3a at different developmental stages. Results: CnHd3a was expressed in leaves and the shoot apical meristem (SAM) during the flowering transition in both coconut varieties and flower tissues during flower development. Interestingly, the expression levels of complex isoforms of CnHd3a were higher in the leaves of dwarf coconuts than in those of tall coconuts, suggesting their involvement in shortening the vegetative growth phase of dwarf coconuts. The gene structure of CnHd3a was found to be conserved across different plant species, indicating the evolutionary conservation of the floral transition process. Conclusions: Our findings provide insight into the molecular mechanisms underlying the floral transition and flower development processes in coconut palm. The tissue-specific expression patterns of CnHd3a isoforms show their potential roles in growth and development. Further investigations focusing on the functional characterization of CnHd3a isoforms will have practical implications for coconut breeding and cultivation strategies.