Biomass Dry Weight Research Articles

Effects of Major Fungal Pathogens on Growth and Yield of Improved and Local Sorghum Genotypes under Field Trials in Lower Eastern Kenya

Sorghum is a climate resilient cereal that offers food and nutrition security for the arid and semi-arid lands (ASALs). Its production potential is however limited by fungal diseases. A study on the effects of major fungal diseases on sorghum growth and yield and identification of tolerant genotypes is critical for sustainable sorghum production. A total of 14 germplasms were analyzed under a two-seasonal field trial laid out in Randomized Complete Block Design with four replications at two different agro-ecological zones within Kenya’s ASALs. A spreader row technique using a highly susceptible variety and natural infections was used for fungal inoculation. Ten plants randomly sampled and tagged from two inner rows in each plot, were used to asses plant growth, yield, and diseases. Diseases were identified using identification keys, visual symptoms, and signs and effects scored through disease severity (DS) and disease incidence (DI). Identified diseases included anthracnose, leaf blight, rust, gray leaf spot, ladder leaf spot, oval leaf spot, downy mildew, and covered kernel smut. Higher DS (>7.0) and DI (>50%) were recorded in anthracnose, leaf blight, and leaf rust across most genotypes. The significant (P≤0.01) negative correlations between DS and days to 50% flowering, number of green leaves, leaf area and panicle width indicated potential disease inhibition of sorghum growth. Correlations between DS and dry biomass, grain yield and grain weight were also negative but insignificant (P>0.05) implying no disease effects on sorghum yield. Improved genotypes had the least foliar and panicle infections and produced significantly higher grain yield (>2.0 t/ha) compared to local varieties with lower yield (<1.5t/ha) and higher foliar and panicle symptoms. The improved genotypes were thus classified as tolerant to fungal diseases and could be used to support resistance breeding programs as a sustainable management strategy for improved sorghum production in ASALs of Kenya.

Effect of varieties and applications of clove oil on growth, productivity, and pest and disease resilience of soybean

Efforts to increase soybean productivity are carried out in various ways, including improving cultivation technology and applying pest and disease control technologies for soybeans. In addition to chemical pesticides, pest and disease control can use botanical pesticides or biopesticides, including those made from clove oil. This study aimed to determine the effect of varieties and clove oil on the growth, production, and pest-disease resilience of soybean. The study was conducted at Majalengka Regency, West Java, Indonesia from April to July 2021. The research used a factorial randomized complete block design with four replications. The first factor was soybean genotypes: Dena 1, Dega 1, and Anjasmoro. The second factor was the concentration and interval of application of clove oil: control, 3 mL L-1 with an interval of 10 days, 3 mL L-1 with an interval of 15 days, 5 mL L-1 with an interval of 10 days, and 5 mL L-1 with an interval of 15 days. The results showed that the Dena 1 variety had the highest plant height, number of branches, number of pods per plant, and dry weight per plant. The Dega 1 variety produced the highest weight of plant dry mass, dry pod shell weight, and 100-grain. Anjasmoro variety had the highest root length and number of nodules per plant. The Anjasmoro was more resistant to leaf caterpillar attacks, while the Dena 1 was more resistant to leaf rust disease. Botanical pesticides derived from clove oil affected various aspects of soybean growth including plant height at 60 days after planting, weight of dry biomass, root length and number of root nodules per plant, dry pod shell weight, dry seed weight, and 100-grains weight.
 Keywords: botanical pesticide; clove oil; Glycine max; root nodulation; variety

Application of humic acid supplemented with micronutrient increase rice production

Fertilizer is one of the crucial inputs to maximize nutrients needed by plants, especially rice. However, insufficient ameliorant application may affect the fertilizers' effectiveness. Humic acid is believed as one of the ameliorants to improve soil conditions resulting in higher nutrient availability. The study aimed to evaluate the effect of combining humic acid and micronutrients on growth, production, and nutrient contents in rice. Three treatments were applied, i.e., control (without humic acid), humic acid, and humic acid + micronutrients. The result showed that both humic acid treatments produced the highest number of tillers, humic acid application solely stimulated the highest root length, and humic acid + micronutrients stimulated the highest plant height, and fresh and dry biomass weight. Grain weight was not affected by treatments, but humic acid + micronutrients gave a higher weight of milled grain and number of filled grains. Humic acid application solely resulted in plant biomass and grains having higher N, P, and K contents. Overall, the application of humic acid + micronutrients is recommended to increase rice production.
 Keywords: ameliorant; fertilizer; nutrient availability; nutrient uptake

Potencial of Rice Bran Extract as a Basic Ingridient in Candida albicans Culture Media

Rice bran is a natural material that contains nutrients that serves as a fungal growth factor, can be used as an alternative media base for fungal growth. The aim of this research is to determine the potential of rice bran as an alternative medium for the growth of Candida albicans. The research design employed an experiment that compared the growth of Candida albicans on rice bran extract media and Sabouraud Dextrose Agar (SDA) media. The sample is rice bran powder obtained from rice mills and rice bran extract was made using a multi-stage pretreatment method. The rice bran extract was used to create Rice bran Agar (RBA) and Rice bran Liquid (RBC) media, while SDA dan (SDB) media were also prepared. The media were inoculated with Candida albicans, incubated, and observed for 5 days. Data analysis included the measurement of fungal colony diameter using One Way Anova and Candida albicans biomass using an independent t-test. The research findings indicate that the average diameter of fungal colonies on RBA extract media was 10.4 mm, whereas it was 12.3 mm on SDA media. The Anova and Post Hoc Tukey HSD results demonstrated significant daily differences in colony diameter on RBA media, indicating notable Candida albicans growth. Conversely, there was no significant difference in colony diameter on SDA media. The biomass average of Candida albicans on RBC media was 0.82 g, compared to 0.45 g on SDB media. The Mann-Whitney test (p < 0.05) indicated a significant contrast in the average dry weight of Candida albicans biomass, with RBC media being heavier than SDB media. The conclusion is RBA and RBC media have the ability to grow Candida albicans which can be used as an alternative to SDA and SDB media.

Uji Kombinasi Pupuk Anorganik Dan Pupuk Bio-Organik P Terhadap Ketersediaan P Dalam Tanah, Serapan P Tanaman, Dan Populasi Bakteri Pelarut Fosfat Pada Tanaman Kedelai (Glycine Max L. Merrill)

The application of bio-organic P fertilizer alongside inorganic fertilizers plays a crucial role in increasing available phosphorus (P) for plants while also aiming to reduce and optimize the use of inorganic fertilizers. This combination is expected to enhance crop yields, balance nutrient availability, and improve soil structure. The objective of this research was to investigate the impact of the combination of inorganic and bio-organic P fertilizers on soil P availability, P uptake in soybean plants, and the population of Phosphate-Solubilizing Bacteria (PSB) during the vegetative phase. The research utilized an experimental approach with four treatments. Each treatment involved five randomly selected samples, resulting in a total of 20 experimental units. The study was conducted from March to July 2019 in paddy fields in Semoyang Village, Praya Timur Subdistrict, Central Lombok Regency. The treatments used were as follows: P1 (50% of the recommended inorganic fertilizer + 10 g of bio-organic P fertilizer per plant), P2 (75% of the recommended inorganic fertilizer + 10 g of bio-organic P fertilizer per plant), P3 (100% of the recommended inorganic fertilizer), and the control group (without any treatment). The parameters analyzed in this study were the available P content in the soil, soil pH, dry weight of biomass, P uptake in plants, and the population of Phosphate-Solubilizing Bacteria. The results demonstrated that the treatments involving the combination of inorganic and bio-organic P fertilizers showed improvements in all tested parameters compared to using only inorganic fertilizers. The soil pH ranged from 6.56 to 6.64, available soil P ranged from 13.2 to 17.33 ppm, dry weight of biomass ranged from 8.2 to 11.01 grams, P uptake in plants ranged from 10.69 to 16.76 mg per plant, and the population of PSB ranged from 1.14×106 cfu/g to 4.56×107 cfu/g.

Duckweed-associated bacteria as plant growth-promotor to enhance growth of Spirodela polyrhiza in wastewater effluent from a poultry farm.

Duckweed has been highlighted as an invaluable resource because of its abilities to remove nitrogen and phosphorus from wastewater coupling with the production of high starch/protein-containing plant biomass. Duckweed recruits microbes and particularly forms a stable "core" bacterial microbiota, which greatly reduces the colonization efficiency of plant growth-promoting bacteria (PGPB). In this study, natural duckweeds were enriched in a sterilized-partially treated wastewater effluent from a poultry farm. After 24days of cultivation, the duckweed-associated bacteria (DAB) were isolated and evaluated for their plant growth-promoting (PGP) potentials by co-cultivation with axenic Spirodela polyrhiza. Ten species were found in more than one location and could be considered candidates for the stable "core" DAB. Among them, all isolates of Acinetobacter soli, Acidovorax kalamii, Brevundimonas vesicularis, Pseudomonas toyotomiensis, and Shinella curvata increased duckweed growth in Hoagland medium. The highest PGP ability was observed in Sh. curvata W12-8 (with EPG value of 208.72%), followed by Paracoccus marcusii W7-16 (171.31%), Novosphingobium subterraneum W5-13 (156.96%), and Ac. kalamii W7-18 (156.96%). However, the highest growth promotion in the wastewater was observed when co-cultured with W7-16, which was able to increase biomass dry weight and root length of duckweed by 3.17 and 2.26 folds, respectively.

Estimates of Phenotypic and Genotypic Variance and Heritability in Eighty-Nine Bambara Groundnut [Vigna subterranea (L.) Verdcourt] Accessions Collected from Six Regions of Niger

The bambara groundnut [Vigna subterranea (L.) Verdc. (Fabaceae)] is a legume mainly cultivated by women, for the nutritional quality of these seeds. It is a so-called minor culture and the improvement of the plant and its popularization remains to be promoted. The objective of this present work is to evaluate the genetic variability of bambara groundnut accessions. The experiment was carried out according to a completely randomized block device with four replications. Twenty-two (22) characters including four (4) phenological, four (4) morphological and fourteen (14) related to yield were evaluated for accessions characterization. Descriptive analysis showed significant differences. The coefficients of variation ranged from 3.51% (maturity date) to 38.87% (shell weight). Significantly high values (CV˃20%) for 8 of the metric parameters were observed. Pod weight per plant and seed weight per plant (r=0.943), yield in kg/ha (r=0.943); seed weight per plant and yield in kg/ha (r=0.999) showed the strongest correlations. The phenotypic and genotypic coefficients of variation were high for dry biomass weight (PCV=42.23%; GCV=28.40%), shell weight (PCV=63.46%; GCV=22.46%) and 100-seed weight (PCV=25.57%; GCV=25.25%). Maturity date (95.77%) and 100-seed weight (99.84%) had high heritabilities. Broad-sense heritability and genetic gain are high for 100-seed weight (H2=99.84%; GA=52.58%). The Ascending hierarchical classification produced four groups of which group 4 is the most efficient in yield with short (20.58cm) early accessions (80.32 days). Groups 1 and 2 include, late accessions (~22cm) with respectively maturity dates (DM=85.67 days and DM=86.53 days.

Ameliorating Effects of Graphene Oxide on Cadmium Accumulation and Eco-Physiological Characteristics in a Greening Hyperaccumulator (Lonicera japonica Thunb.).

Graphene oxide (GO), as a novel carbon-based nanomaterial (CBN), has been widely applied to every respect of social life due to its unique composite properties. The widespread use of GO inevitably promotes its interaction with heavy metal cadmium (Cd), and influences its functional behavior. However, little information is available on the effects of GO on greening hyperaccumulators under co-occurring Cd. In this study, we chose a typical greening hyperaccumulator (Lonicera japonica Thunb.) to show the effect of GO on Cd accumulation, growth, net photosynthesis rate (Pn), carbon sequestration and oxygen release functions of the plant under Cd stress. The different GO-Cd treatments were set up by (0, 10, 50 and 100 mg L-1) GO and (0, 5 and 25 mg L-1) Cd in solution culture. The maximum rate of Cd accumulation in the roots and shoots of the plant were increased by 10 mg L-1 GO (exposed to 5 mg L-1 Cd), indicating that low-concentration GO (10 mg L-1) combined with low-concentration Cd (5 mg L-1) might stimulate the absorption of Cd by L. japonica. Under GO treatments without Cd, the dry weight of root and shoot biomass, Pn value, carbon sequestration per unit leaf area and oxygen release per unit leaf area all increased in various degrees, especially under 10 mg L-1 GO, were 20.67%, 12.04%, 35% and 28.73% higher than the control. Under GO-Cd treatments, it is observed that the cooperation of low-concentration GO (10 mg L-1) and low-concentration Cd (5 mg L-1) could significantly stimulate Cd accumulation, growth, photosynthesis, carbon sequestration and oxygen release functions of the plant. These results indicated that suitable concentrations of GO could significantly alleviate the effects of Cd on L. japonica, which is helpful for expanding the phytoremediation application of greening hyperaccumulators faced with coexistence with environment of nanomaterials and heavy metals.

Enhancing salinity stress tolerance in chickpea (Cicer arietinum L.) genotypes through foliar application of spermidine

Chickpea (Cicer arietinum), the 2nd most important legume after dry beans, known for its protein content, is an important crop agronomically as well as economically. The present study aimed to determine the effect of foliar application of spermidine (spd) on various aspects of chickpea genotypes under salt stress. The chickpea genotypes were cultivated under 4 and 8 dSm-1 Cl- dominated salinity followed by the spermidine application of 0.5 and 1.0 mM. Salinity stress inhibited the plant height and root length, reducing plant biomass (fresh and dry weight). Furthermore, it also decreased the chlorophyll and nitrogen content of the plant. Results obtained from spermidine (spd) application indicated that both concentrations of spermidine are good in enhancing the tolerance in chickpea genotypes against salt stress. Spermidine application increased the plant's height as well as biomass. It also enhanced the chlorophyll content (32.93%), increasing the Nitrogen Balance Index (77.37%) at 1.0 mM.It further increased the flavonoid and anthocyanin content in plant leaf. In addition, the application of spermidine retained more moisture (25.81%) and increased seed fiber (13.30%) in all chickpea genotypes at 1.0 mM. It reduces the Cl- ion accumulation and maintains the ionic balance in chickpea seeds. The effect of spermidine application (0.5 and 1.0mM) was more pronounced, but 1.0 mM had a more positive effect in salt-sensitive chickpea genotypes.

Comparing Vegetation and Substrate Performances on Nutrient Removal and Biomass Establishment Using a Natural Swimming Pool Experiment

Natural swimming pools (NSPs) rely on the interaction of bog vegetation, bacteria, and substrate to maintain water quality. Nitrogen (N) and phosphorus (P) levels in NSPs are critical because of their involvement in eutrophication. We conducted a 15-week greenhouse study to address the significant literature gap regarding nutrient removal capabilities of substrates and vegetation in the low-nutrient environment of NSPs. We used mass balance analyses to compare the performances of four substrates [river gravel (control), recycled glass, expanded clay, expanded shale] and two plant species [blue flag iris (Iris versicolor) and lizard’s tail (Saururus cernuus)] under two flow conditions: free water surface and subsurface flow. At the end of the experiment, except for the recycled glass group, all other substrate groups reduced water nitrate (NO3) levels to less than 30 mg⋅L−1, the standard of the 2011 Forschungsgesellschaft Landschaftsentwicklung Landschaftsbau (FLL) guidelines. However, only the expanded clay group closely approached the P standard (≤0.01 mg⋅L−1). Expanded clay and expanded shale demonstrated potential as substrates for NSP bogs. The final aboveground biomass dry weight was strongly negatively correlated with the final NO3 and P water concentrations. However, direct plant uptake proved insufficient to remove all nutrient inputs, especially for P. Except for the recycled glass group (34%), a significant portion of N (79%–90%) from total N added was removed by aboveground biomass. However, P uptake by biomass was substantially lower (18%–37%). With acceptable vigor and biomass accumulation, blue flag iris may be a suitable species for vegetated NSPs, whereas lizard’s tail is not because of uncertain establishment. Compared with controlling N, managing P for FLL standards in NSPs will be more challenging. Our work begins to fill the essential gap in the NSP literature regarding nutrient removal capabilities of substrates and vegetation. Future work should continue to study alternative substrates and plant species for P removal, particularly in field conditions and over longer periods.

Polyethylene microplastics alter soil microbial community assembly and ecosystem multifunctionality

Although pervasive microplastics (MPs) pollution in terrestrial ecosystems invites increasing global concern, impact of MPs on soil microbial community assembly and ecosystem multifunctionality received relatively little attention. Here, we manipulated a mesocosm experiment to investigate how polyethylene MPs (PE MPs; 0, 1%, and 5%, w/w) influence ecosystem functions including plant production, soil quality, microbial community diversity and assembly, enzyme activities in carbon (C), nitrogen (N) and phosphorus (P) cycling, and multifunctionality in the maize–soil continuum. Results showed that PE MPs exerted negligible effect on plant biomass (dry weight). The treatment of 5% PE MPs caused declines in the availability of soil water, C and P, whereas enhanced soil pH and C storage. The activity of C-cycling enzymes (α/β-1, 4-glucosidase and β-D-cellobiohydrolase) was promoted by 1% PE MPs, while that of β-1, 4-glucosidase was inhibited by 5% PE MPs. The 5% PE MPs reduced the activity of N-cycling enzymes (protease and urease), whereas increased that of the P-cycling enzyme (alkaline phosphatase). The 5% PE MPs shifted soil microbial community composition, and increased the number of specialist species, microbial community stability and networks resistance. Moreover, PE MPs altered microbial community assembly, with 5% treatment decreasing dispersal limitation proportion (from 13.66% to 9.96%). Overall, ecosystem multifunctionality was improved by 1% concentration, while reduced by 5% concentration of PE MPs. The activity of α/β-1, 4-glucosidase, urease and protease, and ammonium-N content were the most important predictors of ecosystem multifunctionality. These results underscore that PE MPs can alter soil microbial community assembly and ecosystem multifunctionality, and thus development and implementation of practicable solutions to control soil MPs pollution become increasingly imperative in sustainable agricultural production.

Rhizoglomus variabile and Nanoglomus plukenetiae, Native to Peru, Promote Coffee Growth in Western Amazonia.

Coffee (Coffea arabica) is among the world's most economically important crops. Coffee was shown to be highly dependent on arbuscular mycorrhizal fungi (AMF) in traditionally managed coffee plantations in the tropics. The objective of this study was to assess AMF species richness in coffee plantations of four provinces in Perú, to isolate AMF isolates native to these provinces, and to test the effects of selected indigenous AMF strains on coffee growth. AMF species were identified by morphological tools on the genus level, and if possible further to the species level. Two native species, Rhizoglomus variabile and Nanoglomus plukenetiae, recently described from the Peruvian mountain ranges, were successfully cultured in the greenhouse on host plants. In two independent experiments, both species were assessed for their ability to colonize coffee seedlings and improve coffee growth over 135 days. A total of 35 AMF morphospecies were identified from 12 plantations. The two inoculated species effectively colonized coffee roots, which resulted in 3.0-8.6 times higher shoot, root and total biomass, when compared to the non-mycorrhizal controls. R. variabile was superior to N. plukenetiae in all measured parameters, increasing shoot, root, and total biomass dry weight by 4.7, 8.6 and 5.5 times, respectively. The dual inoculation of both species, however, did not further improve plant growth, when compared to single-species inoculations. The colonization of coffee by either R. variabile or N. plukenetiae strongly enhances coffee plant growth. R. variabile, in particular, offers enormous potential for improving coffee establishment and productivity. Assessment of further AMF species, including species from other AMF families should be considered for optimization of coffee growth promotion, both alone and in combination with R. variabile.

Vigna unguiculata: a productive option in the face of climate change?

Faced with the challenges of extreme climatic events and increasing food demand, cowpea farming offers a viable option for generating grains and foliage while aiding soil preservation. This research aimed to evaluate the impact of diverse organic fertilizers and plastic mulches on cowpea yields and soil macrofauna. A completely randomized block design was employed, with a factorial arrangement of 3 × 3 + 1, encompassing plastic mulch (3.5 mm) color (white, black, and blue), organic fertilizer (compost of chicken manure-agricultural soil-dolomite, island guano, and cattle manure compost), as well as a control (without synthetic mulch and organic fertilization). The study evaluated soil temperature, plant height, area biomass, foliar macronutrients, yield, and soil macrofauna. The findings demonstrate that soil temperature varies based on the color of the plastic mulch. It was observed that using organic fertilizers resulted in significantly taller plants than the control group, with fresh and dry biomass weight also being significantly greater (p<0.05) for cattle manure compost compared to the other treatments. Furthermore, the use of plastic mulches had an impact on soil macrofauna. Cowpea displayed resistance to low soil fertility and fluctuations in soil temperature ranging from <35°C to >40°C. However, high precipitation during the fruiting and harvesting seasons significantly impacted grain yields. Organic fertilizers produced noticeable variances (p<0.05) in the aerial biomass weight of cowpeas, particularly cattle manure compost. The data, indicates that soil macrofauna, like the earthworm Pontoscolex corethrurus, improved the availability of N, P, and K to the plant during the reproductive stage. Plastic mulches and organic fertilizers were linked to an increase in earthworm weights, specifically P. corethrurus. Additionally, plastic mulches served as a physical barrier against ants and bugs.

Элементы технологии производства микробиопрепаратов на основе перспективных бактериальных штаммов антагонистов возбудителя сухой гнили подсолнечника

The elements of production technologies of microbiopreparations in a preparative form wetting powder at a stationary surface cultivation of promising bacterial antagonist strains of a dry rot pathogen on sunflower. The optimal sources of nitrogen and carbon-based and compound nutrient media for cultivation of three promising bacterial strains from the genera Bacillus and Pseudomonas. An excellent source of nitrogen for a strain 5B-1 Bacillus subtilis is corn steep liquor, and of carbon – glycerin and molasses. The highest weight of dry bacterial biomass of a strain D 1-1 Bacillus sp. was on a nutrient medium where sodium nitrogen was used as a nitrogen source and sucrose and molasses – as a carbon-based source. For both bacterial strains of a genus Bacillus the optimal were such compound nutrient media as Chapek’s for bacteria and Tylon-3. For cultivation of a strain 14-4 Pseudomonas sp. the best nitrogen sources were corn steep liquor and sodium nitrogen, and carbon-based – sucrose. The most optimal compound nutrient medium for these strains were King B and Chapek’s for bacteria.

RL-WG26 mediated salt stress tolerance in rice seedlings: A new insight into molecular mechanisms

Soil salinization has significant deleterious impacts on arable lands and crop productivity worldwide. Plant growth–promoting rhizobacteria (PGPR) have the capability to establish mutualistic associations with plants, resulting in the increase of plant growth under abiotic stress. PGPR strain RL-WG26 was previously isolated from the rhizosphere of rice Sea Rice 86 (SR86). In this study, by genome-based average nucleotide identity (ANI) calculation, RL-WG26 was re-identified as Pseudomonas promysalinigenes here instead of Pseudomonas putida. SR86 seedlings inoculated with RL-WG26 possessed significant increases in plant biomass (fresh weight and dry weight), root surface area and length, and chlorophyll content under either normal or saline conditions, when compared with those without RL-WG26 inoculation. Ion content analysis demonstrated that seedlings inoculated with RL-WG26 contained lower Na+ and Cl– accumulation but higher K+ and Ca2+ uptake under saline condition, which finally alleviated the salt ion toxic in the RL-WG26 inoculated seedlings, when compared with those without RL-WG26 inoculation. In addition, SR86 seedlings inoculated with RL-WG26 also exhibited higher antioxidant activity and higher concentration of osmoregulation factor proline than those without RL-WG26 inoculation. At last, genomic analysis of strain RL-WG26 identified several genes and gene clusters encoding 1-aminocyclopropane-1-carboxylic acid (ACC)-deaminase, the tryptophan-dependent indole-3-acetic acid (IAA) synthesis pathway, and the synthesis of betaine. Taken together, PGPR strain RL-WG26 could enhance the growth and salt stress tolerance in SR86 seedlings through various pathways, which provide a foundation for deciphering the molecular mechanisms of strain RL-WG26-mediated plant salt tolerance and promote the application of this strain.

Analysis of the growth profile, biochemical composition and nutrient removal efficacy of Spirulina sp. NCIM 5143

In the present manuscript, the growth profile of the microalgae Spirulina sp. NCIM 5143 was studied. Screening was performed on four commercial media, i.e., blue‒green-11 (BG-11), Bold’s basal medium (BBM), algal culture medium (ACM), Zarrouk’s medium (ZM), and different concentrations (20%, 40%, 60%, 80%, and 100%) of unsterilized dairy effluent (UDE). Characterization of biomass was performed to assess its biochemical composition through various assays. Elemental composition and bioactive compound analysis were accomplished by inductively coupled plasma-atomic emission spectroscopy (ICP‒AES) and gas chromatography‒mass spectrometry (GC‒MS), respectively. The results revealed that maximum values of most of the parameters, i.e., optical density (0.21), chlorophyll (2.00 mg/l), proteins (119.17 mg/l), and wet (4.06 g/l) and dry biomass weight (0.28 g/l), were found on ZM. For UDE, maximum growth parameters and the highest nutrient removal efficiency were obtained at 100% concentration. Biochemical analysis revealed that total Kjeldahl nitrogen (7.14±0.49%), crude protein (48.23± 3.34%), total antioxidant activity (3.07±0.03 mg AAE/g), and total phenols (8.88±1.93 mg GAE/g) were present in the biomass. Elemental and GC‒MS analysis detected essential micronutrients and many bioactive compounds, respectively. Hence, this study proved that Spirulina sp. NCIM 5143 has the potential for the management of waste dairy effluent. This study also showed its cost-effectiveness, as the dairy effluent analyzed is used without any kind of sterilization. In addition, its biomass is rich in several essential elements, antioxidants, and bioactive compounds of therapeutic and nutraceutical importance.

A multi-objective optimization approach for the production of polyhydroxybutyrate via Chlorogloea fritschii under diurnal light with single-stage cultivation

The present study aims to optimize the nutrients for maximization of cyanobacterial biomass with high content of polyhydroxybutyrate (PHB), a bioplastic, and recovery of biomass by auto-sedimentation under diurnal light mimic to sunlight. The multi-objective optimization with desirability approach was used to improve dry cell weight (DCW), PHB content (% w/w), and auto-sedimentation concentration factor (SCF) of biomass. Initially, NaNO3, K2HPO4, TRACE (micronutrient solution), Na2EDTA, and MgSO4.7H2O were screened as important media compositions. Screening was followed by the application of response surface methodology for the development of a model used in multi-objective optimization. The optimized media selected from many optimal solutions, a set of Pareto solutions generated by multi-objective optimization was validated in a flat panel photobioreactor. Using a single-stage cultivation strategy under diurnal light, Chlorogloea fritschii TISTR 8527 has shown capability to produce DCW of 1.23 g/l with PHB content of 31.78 % and SCF of 93.63 with optimal media. This leads to the enhancement of both PHB content (2.72 fold) and SCF (1.64 fold) were observed when compared to the non-optimal medium. This is the first multi-objective optimization study for media optimization using cyanobacteria reported till now under diurnal light mimic to sunlight for bioplastic production.

COI metabarcoding better reveals the seasonal variations in the zooplankton community in the western Pacific Warm Pool

The environment of the western Pacific Warm Pool is considered to be pronouncedly uniform and stable compared with other tropical ocean environments. Knowledge of the seasonal variations in the zooplankton community structure in this region with a high plankton species diversity remains limited. In this study, three methods, including identification using microscopy, ZooScan digital imaging, and DNA metabarcoding, were used to analyze zooplankton samples collected in three seasons, and to detect the seasonal variations in the community. The results show that the metabarcoding method based on the mitochondrial cytochrome c oxidase I (COI) marker detected up to 2.3 times more zooplankton taxa than identification using microscopy. In contrast, the small subunit ribosomal RNA (18S) marker revealed fewer taxa than microscopy. Significantly positive correlations were observed between the sequence counts and three types of quantitative data, including the biovolume, dry weight biomass, and carbon biomass in all three seasons. The COI sequence counts exhibited a stronger correlation with the dry weight biomass than the biovolume and carbon biomass. Although both the microscopic and molecular methods detected seasonal variability of the zooplankton community, the COI metabarcoding method was more sensitive in detecting seasonal variations in the community, which was positively correlated with the taxonomic resolution of the different methods. In summary, the results of this study suggest that COI metabarcoding is an ideal tool for monitoring the seasonal variations in the diversity and community structure of zooplankton in the tropical open ocean regions with a stable environment all year round.

In-vitro polymicrobial oral biofilm model represents clinical microbial profile and disease progression during implant-related infections.

Clinically relevant in-vitro biofilm models are essential and valuable tools for mechanistically dissecting the etiopathogenesis of infectious diseases and test new antimicrobial therapies. Thus, the aim of this study was to develop and test a clinically relevant in-vitro oral polymicrobial biofilm model that mimics implant-related infections in terms of microbial profile. For this purpose, 24-well plate system was used to model oral biofilms, using three different microbial inoculums to grow in-vitro biofilms: (1) human saliva from periodontally healthy patients; (2) saliva as in inoculum 1+Porphyromonas gingivalis strain; and (3) supra and subgingival biofilm collected from peri-implant sites of patients diagnosed with peri-implantitis. Biofilms were grown to represent the dynamic transition from an aerobic to anaerobic community profile. Subsequently, biofilms were collected after each phase and evaluated for microbiological composition, microbial counts, biofilm biomass, structure, and susceptibility to chlorhexidine (CHX). Results showed higher live cell count (P<.05) for biofilms developed from patients' biofilm inoculum, but biomass volume, dry weight, and microbiological composition were similar among groups (P>.05). Interestingly, according to the checkerboard DNA-DNA hybridization results, the biofilm developed from stimulated human saliva exhibited a microbial composition more similar to the clinical subgingival biofilm of patients with peri-implantitis, with proportions of the main pathogens closer to those found in the disease. In addition, biofilm developed using saliva as inoculum was shown to be susceptible to CHX with significant reduction in bacteria compared with biofilms without exposure to CHX (P<.05). The findings suggested that the in-vitro polymicrobial biofilm developed from human saliva as inoculum is a suitable model and clinically relevant tool for mimicking the microbial composition of implant-related infections.

Temporal changes in zooplankton indicators highlight a bottom-up process in the Bay of Marseille (NW Mediterranean Sea).

Sixteen years (2005-2020) of zooplankton monitoring in the Bay of Marseille (N-W Mediterranean Sea) are analyzed in relation to physical, meteorological, climatic and biotic data. Samples were collected every two weeks by a vertical haul (0-55 m) of a 200 μm plankton net. Different indices characterizing the mesozooplankton are compared: biomass dry weight of four size fractions between 200 and 2000 μm; abundances of the whole of the mesozooplankton and of 13 main taxonomic groups defined from plankton imagery; seasonal onset timing of each zooplankton group; and two other types of indices: the first characterized diversity based on abundance data, and the second was derived from zooplankton size spectra shape. The clearest pattern in the environmental compartment was an overall decreasing trend in nutrients, shifts in phytoplankton metrics (i.e. size structure and particulate organic matter), and changes in winter conditions (i.e. increasing temperatures, precipitation and NAO). Interannual patterns in the mesozooplankton community were: (i) a decrease of total abundance (ii) a decrease in biomass for the four size fractions, with an earlier decrease for the 1000-2000 μm size fraction (in 2008); (iii) a reduced dominance of copepods (calanoids and oithonoids) and a concomitant increase in abundance of other taxonomic groups (crustaceans, pteropods, chaetognaths, salps) which induced higher diversity; (iv) a first shift in size spectra towards smaller sizes in 2009, when the 1000-2000 μm size fraction biomass decreased, and a second shift towards larger sizes in 2013 along with increased diversity; and (iv) a later onset in the phenology for some zooplankton variables and earlier onset for salps. Concomitant changes in the phytoplankton compartment, winter environmental conditions, zooplankton community structure (in size and diversity) and zooplankton phenology marked by a shift in 2013 suggest bottom-up control of the pelagic ecosystem.