Bumblebee Foraging Dynamics and Pollination Outcomes for Cherry Tomato and Pear Varieties in Northern China

Bumblebees (Bombus terrestris) have strong environmental adaptability and high pollen transfer efficiency, making them well-suited pollinators of economic crops. However, bumblebee pollination is still not widely applied in northern China due to the lack of data on foraging behavior and pollination effects. We conducted a three-year experiment involving cherry tomatoes (Solanum lycopersicum L.) and pears (Pyrus spp.) treated with bumblebee pollination to evaluate the foraging behavior and pollination effects on these two crops. Results showed that B. terrestris had enhanced foraging activities as daytime temperatures rose from 18 °C to 26 °C, as indicated by the increased number of bees leaving the hive and returning bees carrying pollen in greenhouses in winter. There were two peaks in the foraging activity of bumblebees in pear orchards in early spring, which was closely related to the temperature change in the daytime. Undoubtedly, cherry tomatoes treated with B. terrestris had higher fruit setting rate, weight, seed number, and fruit yields compared to those with hormone 2,4-dichlorophenoxyacetic acid treatments, as well as a lower rate of deformed fruits. B. terrestris pollination can significantly increase the fruit setting rate and fruit yield of pears, compared with open pollination, and can fully achieve the effect of hand pollination. B. terrestris pollination can improve cultivation efficiency, increase yield, and produce more economic benefits. Moreover, it can also contribute to reducing hormone residues and ensure the safety of agricultural products. We recommend its application to cherry tomatoes in greenhouses in winter and potential application to pears in orchards in early spring in northern China. However, the risk to local bumblebee species of introducing commercially available bumblebees into orchards should be considered and evaluated in future research. This study provides both empirical support and a theoretical basis for the selection of bumblebees as pollinators in the production of economically important crops and the improvement of crop cultivation management in northern China.

Environmental conditions during glycerol bioconversion affect 3-hydroxypropionic acid bioproduction by Limosilactobacillus reuteri DSM 17938

3-Hydroxypropionic acid (3-HP) is a platform molecule whose biological production was carried out by the bacterium Limosilactobacillus reuteri according to a two-step process: first, a growth phase in batch mode on glucose, then a glycerol bioconversion into 3-HP in fed-batch mode. With the objective of improving 3-HP bioproduction, this study aimed at defining the operating conditions during the bioconversion phase that increases the bioproduction performance. A central composite rotatable design allowed testing various pH levels and specific glycerol feeding rates. By establishing response surfaces, optimal conditions have been identified that were different depending on the considered output variable (final 3-HP quantity, 3-HP production yield and production rate). Of them, 3-HP final quantity and 3-HP production yield were maximized at pH 6.0 and at specific glycerol feeding rates of 60 and 55 mg_gly  g_CDW ^-1  h^-1 , respectively. The specific 3-HP production rate was the highest at the upper limit of the specific substrate feeding rate (80 mg_gly  g_CDW ^-1  h^-1 ) but was not affected by the pH. An additional experiment was carried out at pH 6.0 and a specific glycerol feeding rate of 80 mg_gly  g_CDW ^-1  h^-1 to validate the previous observations. In conclusion, the results showed a significant improvement of 3-HP concentration by 13%, of specific production rate by 34% and of 3-HP volumetric productivity by 39%, as compared to the initial values.

Carrageenan From Kappaphycus alvarezii (Rhodophyta, Solieriaceae): Metabolism, Structure, Production, and Application

Carrageenan is a polysaccharide derived from red algae (seaweed) with enormous economic potential in a wide range of industries, including pharmaceuticals, food, cosmetics, printing, and textiles. Carrageenan is primarily produced through aquaculture-based seaweed farming, with Eucheuma and Kappaphycus species accounting for more than 90% of global output. There are three major types of carrageenan found in red algae: kappa (κ)-, iota (ι)-, and lambda (λ)-carrageenan. Kappaphycus alvarezii is the most common kappa-carrageenan source, and it is primarily farmed in Asian countries such as Indonesia, the Philippines, Vietnam, and Malaysia. Carrageenan extracted from K. alvarezii has recently received a lot of attention due to its economic potential in a wide range of applications. This review will discuss K. alvarezii carrageenan in terms of metabolic and physicochemical structure, extraction methods and factors affecting production yield, as well as current and future applications.

[Development of a purification tag to produce thermostable fused protein]

Self-assembling amphipathic peptides (SAPs) have alternating hydrophilic and hydrophobic residues and can affect the thermal stabilities and catalytic properties of the fused enzymes. In this study, a novel multifunctional tag, S1vw (HNANARARHNANARARHNANARARHNARARAR) was developed to modify fused enzymes. After fusing S1vw at the enzymes/proteins N-terminus through a PT-linker, the crude enzymatic activities of polygalacturonate lyase and lipoxygenase were enhanced 3.1- and 1.89-fold, respectively, compared to the wild-type proteins. The relative fluorescence intensity of the green fluorescent protein was enhanced 16.22-fold. All the three S1vw fusions could be purified by nickel column with high purities and acceptable recovery rates. Moreover, S1vw also induced the thermostabilities enhancement of the fusions, with polygalacturonate lyase and lipoxygenase fusions exhibiting 2.16- and 3.2-fold increase compared with the corresponding wild-type, respectively. In addition, S1vw could enhance the production yield of green fluorescent protein in Escherichia coli and Bacillus subtilis while the production of GFP and its S1vw fusion changed slightly in Pichia pastoris. These results indicated that S1vw could be used as a multifunctional tag to benefit the production, thermal stability and purification of the fusion protein in prokaryotic expression system.

Swelling, mechanical strength, and release properties of probucol microcapsules with and without a bile acid, and their potential oral delivery in diabetes

We have demonstrated a permeation-enhancing effect of deoxycholic acid (DCA), the bile acid, in diabetic rats. In this study, we designed DCA-based microcapsules for the oral delivery of the antilipidemic drug probucol (PB), which has potential antidiabetic effects. We aimed to further characterize these microcapsules and examine their pH-dependent release properties, as well as the effects of DCA on their stability and mechanical strength at various pH and temperature values. Using the polymer sodium alginate (SA), we prepared PB-SA (control) and PB-DCA-SA (test) microcapsules. The microcapsules were examined for drug content, size, surface composition, release, Micro-CT cross-sectional imaging, stability, Zeta potential, mechanical strength, and swelling characteristics at different pH and temperature values. The microencapsulation efficiency and production yield were also examined. The addition of DCA resulted in microcapsules with a greater density and with reduced swelling at a pH of 7.8 and at temperatures of 25°C and 37°C (p < 0.01). The size, surface composition, production yield, and microencapsulation efficiency of the microcapsules remained similar after DCA addition. PB-SA microcapsules produced multiphasic PB release, while PB-DCA-SA microcapsules produced monophasic PB release, suggesting more controlled PB release in the presence of DCA. The PB-DCA-SA microcapsules showed good stability and a pH-sensitive uniphasic release pattern, which may suggest potential applications in the oral delivery of PB in diabetes.