Volatile compounds produced in smoked bacon inoculated with potential spoilage bacteria.

BACKGROUND: Volatile organic compounds (VOCs) produced during meat storage are mainly derived from the decomposition of meat components and the metabolism of spoilage bacteria. VOCs produced in sterile bacon model substrate inoculated or un-inoculated with spoilage bacteria, Staphylococcus xylosus (P2), Leuconostoc mesenteroides (P6), Carnobacterium maltaromaticum (P9), Leuconostoc gelidum (P16) and Serratia liquefaciens (P20), previously isolated, were identified by headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS). Furthermore, combinations of the strains (Pm) were also obtained. RESULTS: In total, 54 volatile compounds, including aldehydes, alcohols, phenols, ketones, alkanes, alkanes, organic acids, esters and so forth, were determined after 45 days of storage in bacon inoculated with potential spoilage bacteria using the HS-SPME/GC-MS method. VOC concentrations of alcohols and organic acids in groups inoculated with bacteria were remarkably higher (P < 0.05) compared to that in control samples. Specifically, some VOCs are closely related to the metabolic activity of the inoculated bacterial strains; for example, 2,3-butanediol was associated with P2, P16 and P20, and acetic acid was mainly related to P6 and P9. CONCLUSION: The results of partial least squares regression indicated that there was a high correlation between the electronic nose sensors and VOCs of smoked inoculated potential spoilage bacteria. These compounds are potentially important for predicting deterioration of smoked bacon. © 2023 Society of Chemical Industry.

Comparisons of lymphocytes profiles and inflammatory cytokines levels in blood of patients with differed severity of infection by human adenovirus type 7.

BACKGROUND: Human adenovirus (HAdV) infection outbreak causes community-acquired pneumonia. Cellular immune dysfunction and hypercytokinemia play important roles in the pathogenesis of adenovirus respiratory infection. Some soluble factors in peripheral blood can assist in judging the virus-induced disease severity. The expression levels of inflammatory cytokines differ among patients with different disease severity. However, whether and how HAdV-7 infection influences the composition of blood immune cells and serum cytokine levels in patients at different disease stages, as well as the diagnosis values of these parameters, have rarely been intensively studied. We aimed to investigate lymphocytes profiles and cytokines levels in blood of patients at different disease stages upon human adenovirus type 7 (HAdV-7) infections, and explored the diagnosis values of the investigated parameters. METHODS: Patients from two outbreaks of HAdV-7 in military of China were categorized into upper respiratory infection (URI) group, common pneumonia (CP) group and severe pneumonia (SP) group according to disease severity. Peripheral blood samples were subjected to routine laboratory tests, while flow cytometry and ELISA were used to measure the lymphocyte subsets and cytokines in blood, respectively. The receiver operating characteristic (ROC) curves were performed to examine the diagnostic of these blood parameters. RESULTS: Signs of imbalanced lymphocytes composition and hypercytokinemia were observed in HAdV-7-infected patients. The percentages of CD3+ T cells and NK cells were significantly decreased along with the aggravation of the disease, particularly for NK cells and CD4+ T cells. The neutrophil to lymphocyte ratio (NLR) increased significantly in patients with more severe disease. In addition, the levels of serum CXCL10, IL-2 and TNF-α were positively correlated with disease severity, while reduced levels of IFN-γ and IL-10 were found in SP patients. Furthermore, analysis of ROC showed that multiple parameters including the percentage of blood CD3+ cells and serum CXCL10 level could predict the progression of HAdV-7 infection. CONCLUSION: Imbalance of immune state with hypercytokinemia occurred during HAdV-7 infection. The percentages of blood immune cells such as CD3+ T cells and the levels of serum cytokines such as CXCL10 showed potential diagnosis values in HAdV-7 infection.

Multi-Step Structure Image Inpainting Model with Attention Mechanism.

The proliferation of deep learning has propelled image inpainting to an important research field. Although the current image inpainting model has made remarkable achievements, the two-stage image inpainting method is easy to produce structural errors in the rough stage because of insufficient treatment of the rough inpainting stage. To address this problem, we propose a multi-step structured image inpainting model combining attention mechanisms. Different from the previous two-stage inpainting model, we divide the damaged area into four sub-areas, calculate the priority of each area according to the priority, specify the inpainting order, and complete the rough inpainting stage several times. The stability of the model is enhanced by the multi-step method. The structural attention mechanism strengthens the expression of structural features and improves the quality of structure and contour reconstruction. Experimental evaluation of benchmark data sets shows that our method effectively reduces structural errors and improves the effect of image inpainting.

Microbial Inactivation Property of Pulsed Corona Discharge Plasma and Its Effect on Chilled Pork Preservation.

Although plasma, especially atmospheric plasma generated by corona discharge, has been proven to be effective in sterilization and food preservation, its disinfection mechanism on chilled pork is poorly understood. In this research, the bactericidal and preservation effect of corona discharge plasma (CDP) was investigated. The maximum bactericidal effect was found after 20 kV 4 kHz CDP treatment, with 2.77 log (colony-forming unit [CFU]/g), 2.41 log (CFU/g), and 1.36 log (CFU/g) reduction for Pantoea agglomerans, Serratia liquefaciens, and Kurthia zopfii, respectively, after 10 min of exposure. The efficiency of microbial inactivation was attributed to the increase of ozone, hydrogen peroxide and morphological changes. It was observed that the microbial level and total volatile binding nitrogen value of CDP-treated chilled pork samples were suppressed during storage, whereas the increase of thiobarbituric acid reactive substances value and the changes of color were still worthy of attention. The aim of this study was to explore the effect of pulsed CDP on the inactivation of spoilage microorganism inoculated on the surface of fresh pork. The prospect of this technology in meat preservation industry was also investigated.

Changes in the microbial communities in vacuum-packaged smoked bacon during storage.

This study aimed to gain deeper insights into the microbiota composition and population dynamics, monitor the dominant bacterial populations and identify the specific spoilage microorganisms (SSOs) of vacuum-packed bacon during refrigerated storage using both culture-independent and dependent methods. High-throughout sequencing (HTS) showed that the microbial composition changed greatly with the prolongation of storage time. The diversity of microbiota was abundant at the initial stage then experienced a continuous decrease. Lactic acid bacteria (LAB) mainly Leuconostoc and Lactobacillus dominated the microbial population after seven days of storage. A total of 26 isolates were identified from different growth media using traditional cultivation isolation and identification method. Leuconostoc mesenteroides and Leuconostoc carnosum were the most prevalent species since day 15, while Lactobacillus sakei and Lactobacillus curvatus were only found on day 45, suggesting that they could be responsible for the spoilage of bacon. Serratia, Rahnella, Fusobacterium and Lactococcus underwent a dramatic increase at some point in individual batchs which may be considered as potential contributors to the spoilage.

Evolution of Volatile Compounds and Spoilage Bacteria in Smoked Bacon during Refrigeration Using an E-Nose and GC-MS Combined with Partial Least Squares Regression.

The changes in the concentration of volatile organic compounds (VOCs) and biogenic amines (BAs) in smoked bacon during 45-day refrigerated storage is investigated using solid-phase micro-extraction coupled with gas chromatography-mass spectrometry and high-performance liquid chromatography. In total, 56 VOCs and 6 BAs were identified and quantified. The possible pathways leading to their formation are analyzed and considered as the potential signs of microbial activity, especially by specific spoilage microorganisms (SSOs). Leuconostoc and Lactobacillus, which levels increased markedly with the extension of storage time, were recognized as SSOs. An electronic nose (e-nose) was employed to determine the changes in concentration of the odor components per sample present within half an hour. Partial least squares regression was then carried out to analyze the correlation between SSO growth, metabolite concentration, BA accumulation, and e-nose response. The results show that ten VOCs (ethanol, 2-furanmethanol, 1-hexanol, 1-propanol, phenol, 2-methoxyphenol, acetic acid, 3-ethyl-2-cyclopenten-1-one, furfural, and ethyl hexanoate) and three BAs (putrescine, cadaverine, and tyramine) can be associated with the growth of SSOs. Thus, they can be adopted as potential indicators to evaluate and monitor the quality of the bacon and develop appropriate detection methods. E-noses can used to recognize odors and diagnose quality of bacon.

A randomized, double-blind, and placebo-controlled multicenter clinical trial of a novel cytotoxic T-lymphocyte antigen-4 fusion protein, Leining, in Chinese active rheumatoid arthritis patients with an inadequate response to methotrexate.

To assess the clinical efficacy as well as safety profiles of Leining, a novel cytotoxic T-lymphocyte antigen-4 fusion protein, versus placebo in the treatment of Chinese active rheumatoid arthritis (RA) patients with an inadequate clinical response to methotrexate (MTX). In this 24-week, randomized, double-blind, placebo-controlled multicenter study, a total of 440 Chinese patients with active RA with an inadequate response to MTX were randomly assigned to receive Leining (10 mg/kg) or placebo. Clinical response was assessed using the American College of Rheumatology 20 % improvement criteria ACR20, ACR50, and ACR70, with ACR20 as the primary major endpoints. Disease activity scores in 28 joints with erythrocyte sedimentation rate assessment (DAS28-ESR) were used to evaluate disease activity. After 24 weeks of treatment, significantly more patients in Leining group achieved ACR20 response than those in placebo group (70.61 vs. 46.36 %; p < 0.001). Similarly, ACR50 and ACR70 responses of Leining group were significantly higher than those of placebo group (40.30 vs. 22.73 %; p < 0.001 and 16.67 vs. 7.27 %; p < 0.05, respectively). DAS28-ESR in Leining group was significantly reduced compared to that in placebo group, with greater clinically meaningful (>1.2 unit) improvement (54.85 vs. 29.09 %, p < 0.05). Both the rates of remission (DAS28-ESR < 2.6) and low disease activity (DAS28-ESR < 3.2) were greater in the Leining group than those in the placebo group (12.42 vs. 2.73 %; p < 0.05 and 15.45 vs. 2.73 %; p < 0.05 respectively). The overall incidence of adverse events was similar in both Leining and placebo groups. No neutralizing antibodies were detected. Leining demonstrated clinically meaningful efficacy compared with placebo in Chinese patients with active RA despite MTX therapy. Administration of Leining in combination with MTX for 24 weeks was well tolerated.

The Combination of Corona Discharge Plasma and ε-Polylysine for the Inactivation of Serratia liquefaciens.

The purpose of the study was to investigate the mechanism of inactivation of Serratia liquefaciens by different treatments, namely corona discharge plasma (CDP), ε-polylysine (ε-PL), and corona discharge plasma combined with ε-polylysine (CDP plus ε-PL). The results showed that the combined treatment of CDP and ε-PL exhibited significant antibacterial effects. The total number of colonies of S. liquefaciens dropped by 0.49 log CFU/mL following 4 min of CDP treatment, 4MIC ε-PL treatment for 6 h alone decreased the amounts of colonies by 2.11 log CFU/mL, and 6 h of treatment with 4MIC ε-PL after the bacterium was treated with CDP could decrease the number of colonies by 6.77 log CFU/mL. Scanning electron microscopy images showed that the combined treatment of CDP and ε-PL caused the most serious damage to the cell morphology. Electrical conductivity, nucleic acid, and PI staining indicated that the combined treatment dramatically enhanced the permeability of the cell membrane. In addition, the combined treatment led to a significant decrease in SOD and POD enzyme activities in S. liquefaciens, which prevented energy metabolism. Finally, the determination of free and intracellular ε-PL concentrations confirmed that the treatment of CDP could cause the bacteria to bind more ε-PL and exert more significant bacterial inhibition. Therefore, CDP and ε-PL had a synergistic effect in the inhibition of S. liquefaciens.

Pulsed electric field using the needle-needle electrodes for improving the salt diffusion of pork brine salting.

Pulsed electric field (PEF), as an emerging nonthermal processing technology, has attracted extensive attention and research in food processing. In the present study, PEF has been approved that has the potential to enhance salt diffusion in pork. In this study, pork lions were pretreated with PEF before being immersed in the brine (5% NaCl [w/w]) at 4°C to investigate the effect of needle-needle PEF pretreatment on pork brine salting. The changes in the weight, moisture, and salt content were detected during the salting process. The effective diffusion coefficient (De) and mass transfer kinetics were calculated. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) were subsequently used to analyze the microstructure of the pork and the secondary structure of myofibrillar proteins (MPs). The outcomes demonstrated that after brining for 8 h with PEF pretreatment, the weight, moisture, and salt changes increased significantly. The central salt content achieved by 12 h brining after PEF treatment (4.5 kV) is equivalent to that achieved by brining for 20 h without any treatment. The De was raised to 4.0 × 10-10 (PEF) from 3.1 × 10-10 (control). SEM and FTIR results revealed that PEF altered the microstructure of pork and the secondary structure of MP. Our study demonstrated that PEF generated by needle-needle electrodes could effectively promote salt diffusion and shorten salting processing.

Analysis of Microbial Diversity and Dynamics During Bacon Storage Inoculated With Potential Spoilage Bacteria by High-Throughput Sequencing.

Staphylococcus xylosus, Leuconostoc mesenteroides, Carnobacterium maltaromaticum, Leuconostoc gelidum, and Serratia liquefaciens were investigated for their roles in in the spoilage of sterilized smoked bacon. These five strains, individually and in combination, were applied as starters on sliced bacon at 4-5 log10 CFU/g using a hand-operated spraying bottle and stored for 45 days at 0-4°C. Dynamics, diversity, and succession of microbial community during storage of samples were studied by high-throughput sequencing (HTS) of the V3-V4 region of the 16S rRNA gene. A total of 367 bacterial genera belonging to 21 phyla were identified. Bacterial counts in all the inoculated specimens increased significantly within the first 15 days while the microbiota developed into more similar communities with increasing storage time. At the end of the storage time, the highest abundance of Serratia (96.46%) was found in samples inoculated with S. liquefaciens. Similarly, for samples inoculated with C. maltaromaticum and L. mesenteroides, a sharp increase in Carnobacterium and Leuconostoc abundance was observed as they reached a maximum relative abundance of 97.95 and 81.6%, respectively. Hence, these species were not only the predominant ones but could also have been the more competitive ones, potentially inhibiting the growth of other microorganisms. By analyzing the bacterial load of meat products using the SSO model, the relationships between the microbial communities involved in spoilage can be understood to assist further research.

Directional Changes in the Intestinal Bacterial Community in Black Soldier Fly (Hermetia illucens) Larvae.

Black soldier fly (BSF) larvae, Hermetia illucens (Diptera: Stratiomyidae) have emerged as an efficient system for the bioconversion of organic waste. Intestinal microorganisms are involved in several insect functions, including the development, nutrition, and physiology of the host. In order to transform the intestinal bacterial community of BSF directionally, six different potential functional strains (Lysinibacillus sphaericus, Proteus mirabilis, Citrobacter freundii, Pseudocitrobacter faecalis, Pseudocitrobacter anthropi, and Enterococcus faecalis) were added to aseptic food waste, and aseptic food waste was used without inoculants as a blank control to evaluate the changes in the intestinal microbiota of BSF under artificial intervention conditions. These six strains (which were isolated from the larval intestinal tract in selective media and then identified and screened) may be considered responsible for the functional characteristics of larvae. The results imply that the increase in the abundance of Lysinibacillus in the experimental group that was exposed to Lysinibacillus sphaericus was significantly different to the other groups (p < 0.05). The results revealed that it is feasible to transform the intestinal microbiota of BSF directionally; there are differences in the proliferation of different strains in the intestine of BSF.

Conversion of Mixtures of Soybean Curd Residue and Kitchen Waste by Black Soldier Fly Larvae (Hermetia illucens L.).

The production of insect biomass from organic waste is a major challenge in terms of reducing the environmental impacts of waste and maintaining feed and food security. The feasibility of the co-conversion of soybean curd residue (SCR) and kitchen waste (KW) to breed black soldier fly (BSF, Hermetia illucens) larvae was evaluated so as to enhance biomass conversion efficiency and supply animal feed and allow it to be used in biodiesel production. Co-digestion was found to significantly increase larval yield, bioconversion rate, and bioaccumulation of lipid. Partial least squares regression showed that the conversion of 30% SCR with 70% KW is an appropriate proportion. The appropriate performance parameters of BSF were: survival rate (98.75%), prepupal rate (88.61%), larval biomass (30.32 g fresh and 11.38 g dry mass), bioconversion rate (18.45%), efficiency conversion of ingested food (ECI) (28.30%), and FCR (2.51). Our results show that conversion of mixtures (e.g., SCR with KW) by BSF larvae (BSFL) could play an important role in various organic materials management.

Bacterial community dynamics during different stages of processing of smoked bacon using the 16S rRNA gene amplicon analysis.

To identify the microbial community and origin of the spoilage flora of bacon, the changes in microbial population numbers and community structure were followed along the processing line, using culture-independent and culture-dependent methods. 16S rRNA gene amplicon sequencing (16S-seq) analysis showed that community complexity and structure significantly differed at different processing stages. Some 428 bacterial groups were ascertained at genus level, and Acinetobacter, Pseudomonas, Psychrobacter, and Brochothrix were the predominant bacteria on raw meats. After curing specimens dominated by Psychrobacter, Weissella, Vibrio, Leuconostoc, Myroides, Acinetobacter, and Lactobacillus, a total of 33 species were identified by traditional microbiological analyses and direct sequence determination methods. Our results indicated that curing should be considered one of the primary factors during various processing steps, presumably contaminating the products directly or indirectly.

Changes in the phospholipid molecular species in water-boiled salted duck during processing based on shotgun lipidomics.

Knowledge of the changes in the phospholipid molecular species during processing is helpful to understanding the complicated mechanisms of lipid degradation and transformation. The shotgun lipidomics strategy was utilized to analyze the phospholipid (PL) molecular species in raw Pekin duck and the subsequent dynamic changes that occur during the processing of water-boiled salted duck (WSD). Only 110 PL molecular species have been identified in raw duck meat, while a total of 119 PL molecular species were identified during processing, including 33 phosphatidylcholines, 22 phosphatidylethanolamines, 13 phosphatidylglycerols, 18 phosphatidylinositols and 33 phosphatidylserines. Most of the content of PL molecular species gradually decreased during processing, while the content of most of the lysophospholipids (LPLs) increased. After reaching a maximum, the LPLs were obviously reduced during the 3 d of dry-ripening. The results showed that processing techniques, such as dry-curing, dry-ripening and boiling, had a significant effect on the changes in the PLs in WSD. We further screened 10 PL molecular markers, which can be used to distinguish different operating units.

Influence of Salt Content Used for Dry-Curing on Lipidomic Profiles during the Processing of Water-Boiled Salted Duck.

This paper focuses on the effect of dry-cured salt content on lipidomic profiles during the processing of water-boiled salted duck (WSD). The composition of the molecular species of individual phospholipids (PLs) in raw duck meat was identified by shotgun lipidomics, and the changes in the PLs during processing were analyzed with different contents of dry-cured salt (a 4% low-salt group, a 6% medium-salt group, and an 8% high-salt group). In total, 100 molecular species of phospholipids were determined in raw meat, while 122 species were identified during manufacturing processing. We further found that the amount of dry-cured salt had a great influence on 12 phospholipid molecular species, which could be used as markers to distinguish the treatment groups with different amounts of dry-cured salt. A lower dry-cured salt content (less than 6%) not only had a significant effect on the total PL content but also promoted the degradation of individual PLs (especially those containing unsaturated fatty acids).

Effects of different thermal temperatures on the shelf life and microbial diversity of Dezhou-braised chicken.

This work investigated the effects of different thermal temperatures (84 °C for 35 min, 95 °C for 30 min, and 121 °C for 20 min) on the shelf life and microbial diversity of Dezhou-braised chicken. During refrigerated storage at 4 °C, the increase rate of total viable counts, pH and TVB-N value, was lower in 95 °C-treated and 121 °C-sterilized groups, when compared with 84 °C-treated group. Electronic nose revealed that the fresh odor of Dezhou-braised chicken treated by 84 °C and 95 °C could be maintained during storage. Additionally, 95 °C contributed to the maintenance of good texture of chicken. High throughput sequencing showed that Bacillus and Clostridium were only very active in 84 °C-treated samples, but not in 95 °C-treated and 121 °C-sterilized samples. Taken together, 95 °C can be developed as one potential thermal treatment temperature for Dezhou-braised chicken, due to its positive effects on maintaining fresh odor and texture together with extending shelf life while also protecting food safety.

[Expression levels of Cdc2 and Cdc25A mRNA in cattle, yak, and cattle-yak testis].

The infertility of cattle-yak, which is the hybrid offspring of cattle and yak, is a difficult problem in crossbreeding and improvement of yak. Cdc2 and Cdc25A are the key genes of meiosis. The decline of their expression levels will cause the spermatogenesis failure and lead to infertility. Therefore, this study was conducted to study the relationship between the infertility of cattle-yak and the expression levels of Cdc2/Cdc25A genes. The expression profiles were obtained by RT-PCR. Cdc2 and Cdc25A genes were widely expressed in many tissues, which confirmed their important role in cell division and the progression of cell cycle. Real-time quantitative PCR analysis indicated that the expression levels of Cdc2 and Cdc25A in cattle and yak testis were higher than those in cattle-yak (P<0.05). Therefore, low expression levels of Cdc2 and Cdc25A genes may have a relationship with the infertility of cattle-yak.

An allopurinol-controlled, multicenter, randomized, double-blind, parallel between-group, comparative study of febuxostat in Chinese patients with gout and hyperuricemia.

AIM: Febuxostat, a novel non-purine selective inhibitor of xanthine oxidase, has been identified as a potential alternative to allopurinol in patients with hyperuricemia. The purpose of this study was to compare the urate-lowering (UL) efficacy and safety of daily febuxostat and allopurinol in Chinese gout patients with hyperuricemia. METHODS: Gout patients (n = 512) with serum uric acid (sUA) concentrations of at least 8.0 mg/dL were randomized to receive daily febuxostat 40 mg or 80 mg or allopurinol 300 mg for 28 weeks. Prophylaxis against gout flares with meloxicam or colchicine was provided during weeks 1 through 8. The primary endpoint was the percentage of subjects achieving a sUA concentration of <6.0 mg/dL at the last three monthly measurements. RESULTS: The primary endpoint was reached in 44.77% of patients receiving 80 mg of febuxostat, 27.33% of those receiving 40 mg of febuxostat, and 23.84% of those receiving allopurinol. The UL efficacy in the febuxostat 80 mg group was higher than in the allopurinol (P < 0.0001) and febuxostat 40 mg (P = 0.0008) groups. The UL efficacy of the febuxostat 40 mg group was statistically non-inferior to that of the allopurinol group. No significant change in the number of tophi was observed during the final visit relative to baseline in each treatment group. The rate of gout flares requiring treatment from weeks 9 through 28 and the incidence of adverse events was similar among treatment groups. CONCLUSIONS: The UL efficacy of daily febuxostat 80 mg was greater than that of febuxostat 40 mg and allopurinol 300 mg, which exhibited comparable UL efficacy. Safety of febuxostat and allopurinol was comparable at the doses tested.

Early clinical diagnosis of synchronous multiple primary lung cancer.

The diagnosis of synchronous multiple primary lung cancer (SMPLC) remains a formidable challenge. The aim of the present study was to identify useful clues for the clinical diagnosis of SMPLC, in particular for the early stages. The medical records of 10 patients diagnosed with SMPLC with different histological types were analyzed retrospectively. Chest computed tomography (CT) findings showed two pulmonary lesions in all patients. The two lesions displayed malignant characteristics of primary lung cancer. The levels of a number of tumor markers, including carcinoembryonic antigen, neuron-specific enolase, cytokeratin fragment 21-1, squamous cell carcinoma and CA125 increased in 2 patients. Auxiliary examinations of other physical sites in these patients did not show signs of neoplasm metastasis. Two tumors were separately staged and appropriate treatment was carried out based on the revised stage, which provided more benefits for SMPLC patients. The diagnosis of SMPLC might be delayed or mistaken owing to its similarity to neoplasm metastasis. A high index of awareness is required for the early diagnosis of this disease. The malignant characteristics of primary lung cancer in various lesions may be valuable clues for the diagnosis of SMPLC. Alterations in the levels of tumor markers may be a poor diagnostic tool for the detection of SMPLC. Separate biopsies for different pulmonary masses should be performed for clinical staging as soon as possible and reasonable treatment based on the stage should also be selected.

Cloning and characterization of the gene encoding the bovine BOULE protein.

The Deleted in Azoospermia (DAZ) genes encode potential RNA-binding proteins that are expressed exclusively in the germ-line. The bovine Deleted in Azoospermia-like gene is a strong candidate for male cattle-yak infertility. In this work, with the goe goal to further reveal the genetic cause of male cattle-yak sterility, another bovine DAZ family gene, b-boule, was isolated and characterized. The b-boule gene is predicted to encode a polypeptide of 295 amino acids with an RNP-type RNA recognition domain. Tertiary structure analysis shows that b-boule binds specifically to polypyrimidine RNAs and might act as a nuclear ribonucleoprotein particle auxiliary factor during germ cell formation and morphological changes of germ cells. RT-PCR assays revealed that b-boule was expressed specifically in the adult testis. However, an extremely low level of expression was detected in the testis of sterile male cattle-yaks. Microstructure of the testes from sterile males showed that type A spermatogonia were the only germ cells present and that few germ cells developed further than the stage of pachytene spermatocytes. These results suggest that b-boule may function in bovine spermatogenesis, and that low levels of b-boule expression might lead to male sterility in cattle-yaks.