Pasteur, oxygen and the anaerobes revisited

As a biochemist, Louis Pasteur focused on fermentation, demonstrating that it was a vital process. In 1860, he discovered anaerobic life and the strict anaerobes, particularly those responsible for butyric fermentation. Then, in spite of his lack of medical background, Pasteur turned to investigating the role of bacteria in human and animal diseases. In 1877, Pasteur and Joubert described for the first time a pathogenic anaerobe, the 'septic vibrio' (now Clostridium septicum). Not only was the bacterium cultivated, but the disease symptoms described and the disease experimentally reproduced. Pasteur also described what are now known as mixed anaerobic infections. A historical review of Pasteur's work is made in the light of our present knowledge of this field.     

Highlights of the 3rd international BCG symposium: 100th anniversary of the first administration of BCG

2021 was the year of the 100th anniversary of the first administration of the Bacillus Calmette-Guérin (BCG) to a human being. It was the start of a long journey of the world's most widely used vaccine and the oldest vaccine still in use. More than 4 billion children have been vaccinated with BCG for protection against tuberculosis. However, over the years it became apparent that BCG also has beneficial non-specific effects. As such, it provides protection against various heterologous infectious and non-infectious diseases and is used to treat non-muscle-invasive bladder cancer. As BCG was developed at the Institut Pasteur de Lille by Albert Calmette and Camille Guérin, the Institute has celebrated this important anniversary with an international scientific symposium on all aspects of BCG, held from November 17 to 19, 2021 at the Institut Pasteur de Lille. It covered BCG against tuberculosis and described novel vaccine approaches, the effect of BCG against heterologous infections, including BCG and COVID-19, the effect of BCG against cancer, and BCG against auto-immune and inflammatory diseases. To discuss these areas, the symposium gathered close to 200 participants from all five continents, 2/3 on-line. This article presents the highlights of this 3rd International Symposium on BCG.     

Charles Nicolle and the accomplishments of his scientific thought

The author presents in this study the achievements of the scientific thought of Charles Nicolle, chiefly on the basis of two notions: the asymptomatic diseases and the destiny of infectious diseases. Recalling the factors which prevailing about the career of Charles Nicolle, he shows that the asymptomatic diseases became a fundamental notion in infectious pathology as human, animal, viral, bacterial and parasitic diseases. The notion allowed him to open the study of pathogen agents on the fields of the environment, so enriching the epidemiology, the prophylaxis and the medical ecology. After the notion of specificity of microbes pointed out by Pasteur, Charles Nicolle enlarged their implications and conceived the infinite complexity of microbes. The first he introduced in microbiology the notion of mutation and foresaw the birth, the evolution and the death of the infectious diseases. Not so long time after and now these anticipations has been proved.     

Appropriation and commercialization of the Pasteur anthrax vaccine

Whereas Pasteur patented the biotechnological processes that he invented between 1857 and 1873 in the agro-food domain, he did not file any patents on the artificial vaccine preparation processes that he subsequently developed. This absence of patents can probably be explained by the 1844 patent law in France that established the non-patentable status of pharmaceutical preparations and remedies, including those for use in veterinary medicine. Despite the absence of patents, the commercial exploitation of the anthrax vaccine in the 1880s and 1890s led to a technical and commercial monopoly by Pasteur's laboratory as well as the founding of a commercial company to diffuse the vaccine abroad. Pasteur repeatedly refused to transfer his know-how and anthrax vaccine production methods to foreign laboratories, on the grounds that he wished to control the quality of the vaccines produced. Indeed, it was relatively difficult to transfer a method that was not yet perfectly stabilized in the early 1880s. Pasteur also wanted to maintain the monopoly of his commercial company and to increase the profits from vaccine sales so that the Institut Pasteur could be financially independent. The 'Pasteur anthrax vaccine' operating licences are described and analysed in detail in this article.     

Louis Pasteur: the first experimental aerobiologist

Summary Pasteur is a well known scientific giant. However, it is not generally known that in less than a year, in 1860, he founded on precise scientific ground a new science: «micrography» (called Aerobiology since Meier's times (1930's). Not only did he definitely made the spontaneous generation theory disappear for ever, he also presented the true nature of the air spora: a limited cloud of solid dust dispersed by air movements and emptied by gravity. In order to prove the discontinuity of the supposely continuous spontaneous generation, he studied different localities at different seasons, and travelled at different heights. By doing so, he discovered most of Aerobiology's principles: 1) the absolute necessity of volumetric sampling; 2) the heterogeneity of the air spora; and 3) the aerobiological pathway (take-off, dispersal, deposition).Quoi! Je suis engagé depuis vingt années dans un sujet et ne dois pas avoir d'opinion, et le droit de verifier, de contrôler, de discuter et d'interroger appartiendra surtout à celui qui ne fait plus rien pour s'éclairer, à celui qui vient de lire, plus on moins attentivement mes travaux, les pieds sur les chenêts de la cheminée de son cabinet! Louis Pasteur, réponse à Poggiale     

家蚕病原菌LZ10-1的分离鉴定及对鳞翅目害虫的致病性研究

家蚕是一种重要的经济昆虫,家蚕病原细菌造成的蚕病为蚕业生产带来巨大损失。本研究从自然感染病蚕组织中分离得到高致病力的家蚕病原细菌LZ10-1,结合16SrDNA分析和形态学观察结果,菌株LZ10-1为蜡样芽胞杆菌(Bacillus cereus)。对鳞翅目害虫棉铃虫和粘虫添食LZ10-1芽胞原液72h,供试昆虫的矫正死亡率分别为100%和95.7%,表明家蚕病原细菌具有防治农林害虫的潜力,作为杀虫资源具有开发利用的价值。发掘家蚕病原细菌的生防潜力,能提高蚕桑行业现有资源利用,是拓展行业发展新方向的有益探索。     

Parasitology in France: some aspects of the present

Numerous organizations participate and cooperate on parasitological research in France including the Institut national de la Santé et de la Recherche Médicale (INSERM), the Centre national de la Recherche Scientifique (CNRS), the Institut Pasteur, the Institut Fran?ais de Recherche Scientifique pour le Développement en Coopération (ORSTOMM), the Institut national de la Recherche Agronomique (INRA), the Muséum national d'Histoire naturelle (MNHN), the Universities, the Collège de France, the Ecole Pratique des Hautes Etudes (EPHE) as well as various commercial firms. Exchanges and collaborations with foreign workers are continuous and essential to the success of research on tropical diseases. Here, in their own words, Odile Bain, Daniel Camus and Jacques Prod'hon highlight some aspects of current parasitological research in France.     

Pierre Miquel: the first professional aerobiologist

Pierre Miquel (1850–1922) was one of the fathers of Aerobiology, which he called Atmospheric Micrography. After studying both Pharmacy and Medicine, he decided to investigate, under strict protocols, the living organisms of the atmosphere, brought to light by Pasteur some 20 years earlier. All his aerobiological work was done at Paris Montsouris Observatory where he was ‘chief micrographer’ for 34 years. He was an active promoter of using only volumetric methods, and an early believer in ‘micrography statistics’. His most important works dealing with aerobiology were related to weather influences on atmospheric bioaerosols and on their impacts on epidemic diseases.     

In the autophagy trenches: The early research career of Russell L. Deter

Christian de Duve is considered to be one of the founding fathers of autophagy. After all, he coined the term, and he played an instrumental role in the discovery of the lysosome, for which he received the Nobel Prize. There is no question that de Duve is a stellar scientist, but who was the person in the trenches, doing the actual laboratory work in the lab that led to the initial papers on autophagy? Dr. Russell L. Deter wrote the first papers from the de Duve lab that deal with this topic. To get some insight into the origins of this field, I interviewed Dr. Deter, as detailed in this perspective.     

Allelic Variability in the Intronic Region of the Fibroin Heavy-Chain Gene in Silkworm Bombyx mori L. Strains of Brazilian Germplasm Bank

The domesticated silkworm Bombyx mori L. is currently found only in germplasm banks. Therefore, characterization and conservation of this genetic resource is crucial. Based on previous studies that revealed nucleotide differences in silkworm strains, the intron of the fibroin heavy chain gene (H-fib) can be used for molecular silkworm characterization. The H-fib gene has two exons and a unique intron, and encodes the principal component of the silk fiber, the fibroin heavy chain. Therefore, this study aimed to identify the genetic variability of the unique intron of H-fib gene of 20 silkworm strains maintained at the Universidade Estadual de Maringá Brazilian Germplasm Bank (UBGB) by conformation-sensitive gel electrophoresis (CSGE) and nucleotide sequencing. Genomic DNA extracted from silkworm moths was PCR amplified. CSGE revealed that most of the analyzed silkworm strains had only homoduplex molecules. However, DNA from the Japanese strains B106, B82, and M12-2 had two extra DNA fragments produced by heteroduplex molecules, revealing variation between alleles. Sequencing of the H-fib intron was used to confirm the variation previously detected by CSGE and detected a significant polymorphism characterized by a 17-base pair (bp) deletion, a 2-bp insertion, and eight nucleotide substitutions. Although genetic and allelic variability was detected in some silkworm strains, the intron of the H-fib gene revealed not to be the best molecular marker for the characterization of B. mori strains from UBGB.     

Baculoviral infection reduces the expression of four allergen proteins of silkworm pupa

Silkworm (Bombyx mori) larvae are widely used to express exogenous proteins. Moreover, some silkworm pupal proteins can be used as drug‐loading materials for selfexpressed oral tolerance drugs. However, several proteins expressed in silkworm pupae cause severe allergic reactions in humans and animals. Interestingly, some baculovirus vectors have been shown to alter the host gene and its expression in insect cells, but this has not been confirmed in silkworm. Here, we analyzed the effects of infection with an empty B. mori baculovirus (BmNPV) vector on silkworm pupal protein expression. Using a proteomics approach, the allergens thiol peroxiredoxin (Jafrac1), 27‐kDa glycoprotein (p27k), arginine kinase, and paramyosin as well as 32 additional differentially expressed proteins were identified. Downregulation of the messenger RNA expression of the four known allergens was observed after BmNPV infection; subsequent changes in protein expression were confirmed by the western blot analysis using polyclonal antibodies prepared with recombinant proteins of the four allergens. Collectively, these data indicate that the four known allergens of silkworm pupae can be reduced by infection ith an empty BmNPV vector to increase the safety of silkworm pupa‐based exogenous protein expression and drug delivery of oral pharmaceuticals. In addition, the four recombinant allergen proteins may contribute to the diagnosis of allergic diseases of silkworm pupa.     

Description and identification of two new diseases of guariroba palm (Syagrus oleraceae) in Brazil

Guariroba is a palm species native to central Brazil. Seedlings of guariroba with leaf spots of unknown aetiology were found in Patos de Minas, Minas Gerais, Brazil. The leaf spots were manifest as two different symptom types: the first lesion type consisted of necrotic spots with a rounded to elongate shape, with a light colour and dark edges; the second lesion type had a rounded shape, was dark brown in colour with a light brown edge. The objective of this study was to elucidate the aetiology of both diseases. The likely causal agents were isolated and Koch's postulate fulfilled. Subsequently, the ITS region of rDNA from both micro‐organisms were amplified and sequenced. According to the morphological characteristics and molecular analyses, the fungal species were identified as Pestalotiopsis adusta (causing necrotic spots with a rounded to elongate shape, with a light colour and dark edges), and Alternaria tenuissima (causing lesions with a rounded shape, dark brown in colour with a light brown edge). Identification of the causal organisms of these two diseases will help guide management approaches that might be tested to reduce impact of the disease on Guariroba, including the use of fungicides and cultural approaches.     

When did Louis Pasteur present his memoir on the discovery of molecular chirality to the Académie des sciences? Analysis of a discrepancy

Louis Pasteur presented his historic memoir on the discovery of molecular chirality to the Académie des sciences in Paris on May 22nd, 1848. The literature, however, nearly completely ignores this date, widely claiming instead May 15th, 1848, which first surfaced in 1922 in Pasteur's collected works edited by his grandson Louis Pasteur Vallery-Radot. On May 21st, 1848, i.e., one day before Pasteur's presentation in Paris, his mother died in Arbois, eastern France. Informed at an unknown point in time that she was "very ill," Pasteur left for Arbois only after his presentation. Biographies of Pasteur by his son-in-law René Vallery-Radot or the grandson, and Pasteur's collected correspondence edited by the grandson are incomprehensibly laconic or silent about the historic presentation. While no definite conclusions are possible, the evidence strongly suggests a deliberate alteration of the record by the biographer relatives, presumably for fear of adverse public judgment of Pasteur for a real or perceived insensitivity to a grave family medical emergency. Such fear would have been in accord with their hagiographic portrayal of Pasteur, and the findings raise questions concerning the extent of their zeal in protecting his "demigod" image. Universal recognition of the true date of Pasteur's announcement of molecular chirality is long overdue.     

Effect of Cordyceps, Paecillomyces sp., Cordyceps pruinosa and Paecillomyces japonica, on the Development of Domestic Silkworm, Bombyx mori

ABSTRACT This study was carried out to investigate pathogenicity of cordyceps on the silkworm larva, Bombyx mori . For experiment, Cordyceps, Pacillomyces sp. strain collected from Chiak mountain area in Gangwon Province and Pacillomyces japonica collected from dead silkworm larva at the rearing room in Sangju National University were used. Spores of cordyceps were propagated on sterile PDA (potato dextrose agar 39g, water 1,000mL) at 25°C for 21 days. Spores of cordyceps isolated from media were inoculated on integuments of 3rd instar newly exuviated silkworm for pathogenicity on the silkworm larvae. The cordyceps used in this study was highly infectious to the silkworms. Virulence of cordyceps was different depending on species. Pacillomyces japonica was the most efficacious with 70% mortality on silkworm larvae. Cordyceps had adverse effect on the overall rearing from larval period to mounting of matured silkworm larvae, cocoon making, pupation and moth emergence. The result suggests that cordyceps used in this study may be useful for the tracking of biocontrol.     

Phylogeny and evolutionary history of the silkworm

The silkworm, Bombyx mori, played an important role in the old Silk Road that connected ancient Asia and Europe. However, to date, there have been few studies of the origins and domestication of this species using molecular methods. In this study, DNA sequences of mitochondrial and nuclear loci were used to infer the phylogeny and evolutionary history of the domesticated silkworm and its relatives. All of the phylogenetic analyses indicated a close relationship between the domesticated silkworm and the Chinese wild silkworm. Domestication was estimated to have occurred about 4100 years ago (ya), and the radiation of the different geographic strains of B. mori about 2000 ya. The Chinese wild silkworm and the Japanese wild silkworm split about 23600 ya. These estimates are in good agreement with the fossil evidence and historical records. In addition, we show that the domesticated silkworm experienced a population expansion around 1000 ya. The divergence times and the population dynamics of silkworms presented in this study will be useful for studies of lepidopteran phylogenetics, in the genetic analysis of domestic animals, and for understanding the spread of human civilizations.     

Overexpression of recombinant infectious bursal disease virus (IBDV) capsid protein VP2 in the middle silk gland of transgenic silkworm

Infectious bursal disease virus (IBDV) is the causative agent of a highly contagious disease affecting young chickens and causes serious economic losses to the poultry industry worldwide. Development of subunit vaccine using its major caspid protein, VP2, is one of the promising strategies to protect against IBDV. This study aim to test the feasibility of using silkworm to produce recombinant VP2 protein (rVP2) derived from a very virulent strain of IBDV (vvIBDV). A total of 16 transgenic silkworm lines harboring a codon-optimized VP2 gene driven by the sericin1 promoter were generated and analyzed. The results showed that the rVP2 was synthesized in the middle silk gland of all lines and secreted into their cocoons. The content of rVP2 in the cocoon of each line was ranged from 0.07 to 16.10 % of the total soluble proteins. The rVP2 was purified from 30 g cocoon powders with a yield of 3.33 mg and a purity >90 %. Further analysis indicated that the rVP2 was able to tolerate high temperatures up to 80 °C, and exhibited specific immunogenic activity in mice. To our knowledge, this is the first report of overexpressing rVP2 in the middle silk gland of transgenic silkworm, which demonstrates the capability of silkworm as an efficient tool to produce recombinant immunogens for use in new vaccines against animal diseases.     

SWATH‐based quantitative proteomics reveals the mechanism of enhanced Bombyx mori nucleopolyhedrovirus‐resistance in silkworm reared on UV‐B treated mulberry leaves

Bombyx mori nucleopolyhedrovirus (BmNPV) is one of the most acute infectious diseases in silkworm, which has led to great economic loss in sericulture. Previous study showed that the content of secondary metabolites in mulberry leaves, particularly for moracin N, was increased after UV‐B irradiation. In this study, the BmNPV resistance of silkworms reared on UV‐B treated and moracin N spread mulberry leaves was improved. To uncover the mechanism of enhanced BmNPV resistance, silkworm midguts from UV‐B treated mulberry leaves (BUM) and moracin N (BNM) groups were analyzed by SWATH‐based proteomic technique. Of note, the abundance of ribosomal proteins in BUM and BNM groups was significantly changed to maintain the synthesis of total protein levels and cell survival. While, cytochrome c oxidase subunit II, calcium ATPase and programmed cell death 4 involved in apoptotic process were up‐regulated in BNM group. Expressions of lipase‐1, serine protease precursor, Rab1 protein, and histone genes were increased significantly in BNM group. These results suggest that moracin N might be the main active component in UV‐B treated mulberry leaves which could improve the BmNPV‐resistance of silkworm through promoting apoptotic cell death, enhancing the organism immunity, and regulating the intercellular environment of cells in silkworm. It also presents an innovative process to reduce the mortality rate of silkworms infected with BmNPV.     

Transcriptome analysis of the response of silkworm to drastic changes in ambient temperature

Bombyx mori is a poikilothermic insect and is economically important for silk production. Drastic changes in the ambient temperature have a negative impact on sericulture. However, the reason as to why high temperature is associated with the occurrence of diseases in silkworm and the response of silkworm to low temperature remain unclear and were the focus of the present study. Dazao silkworm exposed to 13 °C (DZ-13), 25 °C (DZ-25), and 37 °C (DZ-37) were used for RNA-seq analysis. There were 478 and 194 upregulated differentially expressed genes (DEGs) in DZ-13 and DZ-37 while 49 and 273 downregulated DEGs in DZ-13 and DZ-37, respectively. Eight DEGs were co-upregulated, in which seven genes were for heat shock proteins (Hsps), implying that Hsps play important roles in the tolerance of silkworm to high and low temperature. Gene ontology analysis revealed that the developmental process was downregulated in DZ-13. All the DEGs in the oxidative phosphorylation and insulin signaling pathways were upregulated in DZ-13. Several cuticular proteins and ATP synthesis-related genes were upregulated in DZ-13, suggesting that thickening of the cuticle and increase in the ATPase expression would help silkworms to protect themselves from low temperature-induced stress. Several immune-related genes, such as BmRel and BmSerpin-2, were downregulated in DZ-37, revealing that the resistance of silkworm is decreased under high temperature shock resulting in susceptibility to pathogens. Thus, the increase in the thermo-tolerance of silkworm should be related to the enhancement in the pathogen resistance.

     

Pasteur, Pastorians, and the dawn of immunology: the importance of specificity

Throughout his career, the problems that attracted Louis Pasteur almost invariably involved considerations of specificity of structure and/or of action. Thus, his work on asymmetric crystals showed that chemical form not only specifies crystalline structure, but affects the affinity of ferments as well. In his studies of diseases of silkworms, of beer, and of wine, he could unerringly distinguish with the microscope the specific agents of disease. From this emerged his concept of the specificity of species and against the nonspecificity of spontaneous generation, whence the germ theory of disease. It was in the new field of immunology, however, where the manifestations of an exquisite specificity were most clearly seen. Here, Pasteur's vaccines worked because he chose the specific pathogen in order to induce a specific immunity, and he succeeded each time. But the two most prominent Pastorian successors in immunology, Elie Metchnikoff and Jules Bordet, were not equally successful. Although each contributed significantly to the birth of immunology, each advanced a theory that neglected the principle of specificity and paid a price in consequence. Metchnikoff's phagocytic theory of immunity could not survive the demonstrable specificity of humoral antibodies, while Bordet's physical adsorptive concept of the antibody-cell interaction quickly fell to Paul Ehrlich's demonstration of the stereochemical determination of immunological specificity.     

Bioaccumulation of cobalt in silkworm (Bombyx mori L.) in relation to mulberry, soil and wastewater metal concentrations

The present study was planned to evaluate Co(II) toxicity in silkworm population. The soil was irrigated using synthetic wastewater to determine the effects of pH and initial cobalt concentration in its bioaccumulation in silkworm (Bombyx mori L.) food chain. The amount of cobalt in wastewater, soil, mulberry and silkworm was determined by atomic absorption spectrophotometer (AAS) analysis. The obtained results clearly indicate that silkworm can be used as template to indicate local cobalt pollution as its body length, body weight and mortality rate was found to be strongly related to cobalt concentration. Higher the cobalt amount in mulberry leaves more the toxicity to silkworm population. At 400 mg/L Co concentration and pH 4 there was maximum deposition of Co in the soil from the synthetic effluent. However, in plants and silk worm the accumulation of Co was maximum at pH 4.5 at an initial Co concentration of 400 mg/L in the synthetic effluent. The maximum cobalt found in wastewater, soil, mulberry and silkworm was 400 ± 0.01, 273.5 ± 0.04, 42.85 ± 0.01, 36.62 ± 0.22 mg/kg, respectively.